A Device for Sampling Earlobe Arterialized Blood in Space and Other Austere Environments

*Thais Russomano*

## **Abstract**

The coming decades will see a large increase in the numbers of people who will have the opportunity to go into space, whether on traditional Earth-orbiting space stations, tourist spaceflights or proposed space hotels. In addition, humans are likely to be spending longer periods of time in the microgravity of space and the reduced gravity environments found on the moon and Mars, with plans for long-duration spaceflight to reach the red planet and habitation of a moon colony. The anatomy, physiology and psychology of humankind are shaped by the gravity we are subject to on Earth, and it is known that the removal or reduction of this force can have a detrimental effect on our health and wellbeing. Therefore, all steps must be taken to monitor these aspects. Currently, there is no safe and acceptable method to collect arterial blood in space, which can be used to obtain valuable blood gas and blood component variables. This chapter will outline the development of a method for safely collecting arterialized blood in space, the research and steps taken to ensure its suitability and applicability, in preparation for this growing presence of humans in space.

**Keywords:** space medicine, space physiology, medical emergencies, arterial blood, arterialized blood, blood collector, parabolic flight

## **1. Introduction**

There is an increased need to accurately monitor and medically evaluate human beings in a variety of clinical and research situations in space, with plans for longduration manned spaceflight, the proposed return to the moon and potential moon and Mars colonies in the future. In addition, greater flexibility in the selection process of astronauts and the advent of space tourism increases the need for adequate health and medical monitoring and evaluation in space, requiring improvements in currently available space medical monitoring systems.

The accurate measurement of arterial blood gas tensions, as opposed to venous, in medical practice and physiological studies on Earth and in space is of particular importance, as these can better reflect alterations in performance of the cardiopulmonary system and related diseases. However, there is currently no suitable method to access arterial blood in microgravity, and consequently, values for blood gas tensions are usually derived from measurements of respiratory gas partial pressures. Nonetheless, the measurements of oxygen saturation by oximetry are not considered comprehensive or accurate enough for detailed research or clinical practice.

The utility of finding a solution to this problem is not in doubt. Physiological findings could be confirmed with greater accuracy and more detailed studies conducted in the future. Clinical emergencies could also be managed with greater facility, resulting in increased safety for all crew involved in space missions. To this end, the arterialized earlobe blood collection technique for evaluating blood gas tensions has been considered for use in space, as analyses of the blood obtained could provide valuable information regarding the diagnosis of a number of medical conditions. This technique was first developed in 1944 and adopted under certain circumstances as an alternative to arterial puncture and arterial cannulation [1]. Nonetheless, the current earlobe arterialized blood collection technique is untested in microgravity, as is the risk of contamination of the environment with blood droplets. Therefore, a series of researches and tests have taken place to validate the suitability of the arterialized blood as an analogue of arterial blood and its suitability for use in microgravity, the creation of an easy-to-use and safe device for collecting arterialized blood from the earlobe, validating its use in ground-based studies on Earth and in microgravity, and determining the space preparedness of the device for surviving the stresses caused by a space rocket launch.

## **2. Validation of the arterialized blood technique**

## **2.1 Arterialized versus arterial blood**

Arterial gas analyses are essential for the clinical evaluation of astronauts, since they provide important physiologic information and can be an important tool for performing disease diagnoses during a space mission. However, currently available devices and methods, such as puncture and cannulation of an artery, are considered unsuitable for use in this scenario.

Arterial cannulation, the positioning of an intra-arterial catheter, is a technique which allows continuous and direct monitorization of blood pressure and frequent sample withdrawal for blood analyses. Arterial blood by means of puncture is usually collected from the wrist or from the inner part of the elbow or other arteries, through the insertion of a needle in a previously cleaned area. The blood then flows into a heparinized syringe, and the needle is removed as soon as enough blood is collected [2].

Both arterial cannulation and puncture are known to be difficult techniques to perform, requiring specialist training, causing pain to the patient and having the possibility of contamination of the environment with blood droplets. Moreover, although low, there is an increased risk of serious complications, such as haematoma, excessive bleeding and infection. Therefore, it is well accepted that the direct sampling of arterial blood is unsuitable for use in many austere environments, such as in space missions [2].

The earlobe arterialized blood technique makes use of the fact that the capillary blood taken from the arterialized earlobe originates from the arterioles and thus has the composition of arterial blood. The technique has been available as a substitute for arterial puncture for more than 60 years in clinical medicine and physiological research. The success of the technique depends upon careful preparation of the earlobe, which is arterialized by rendering it hyperaemic. This can be executed by heating the earlobe or massaging it with a rubefacient cream, thus ensuring free flow of blood from any incision made. The time of preparation varies from study to study, though conventionally it ranges from 3 to 10 minutes, with the standard being around 4 minutes. Ensuring adequate vasodilatation is of primary

**159**

**Table 1.**

*earlobe.*

Level of discomfort

Potential complications

*A Device for Sampling Earlobe Arterialized Blood in Space and Other Austere Environments*

importance; therefore, if the earlobe is not hyperaemic after 4 minutes of preparation, massage or heating should continue. Conventionally, the skin of the earlobe is cleaned with alcohol, and a puncture, 2–4 mm deep, is made with a sterile blade. The blood is collected in a heparinized capillary tube or cartridge, which is held in such a way that the blood enters anaerobically by capillary action. This blood can

**Table 1** summarizes the differences between the two techniques of blood collection via arterial puncture and blood collection from an arterialized earlobe.

**2.2 Earlobe arterialized blood technique in microgravity simulation studies**

A series of studies were conducted at King's College London, as part of the PhD thesis entitled 'The effect of 3h of 6-degree Head-Down Tilt (HDT) with and without hypoxia and light exercise on lung function' [7], with the aim of evaluating

There was first the need to establish whether the lower to upper body redistribution of blood that occurs during microgravity exposure, with the subsequent venous congestion of the face and neck of astronauts, could cause contamination of the arterial blood from venous blood, thereby affecting results. The arterialized capillary blood sample technique had not been used previously during groundbased microgravity simulations, parabolic flights or space missions, and therefore, a preliminary study was designed to evaluate the possible effect of the head congestion on the gas tensions of earlobe arterialized blood samples. In order to avoid the cardiopulmonary changes associated with tilting to the 6° head-down position, the ground-based microgravity simulation used, the increase in venous pressure in the earlobe associated with this position was reproduced by inflating a cuff around

The venous pressure at the earlobe was calculated as the change in the vertical height of the ear relative to the heart on transition from supine to 6° head-down. Assuming a 30 cm distance between the earlobe and the right atrium, the increase

Potentially painful Virtually pain-free

• Hemorrhage—from the earlobe, and therefore easily controlled with direct

• Cutaneous infection at incision site

Potential for many spheres of use: **Terrestrial:** hospitals, private clinics,

Very easy technique to learn and carry out by non-medically qualified personnel

pressure

(superficial)

rural health centres **Aeronautic:** patient transport **Space:** space station, extraterrestrial bases for research and medical use

**Characteristic Radial artery Arterialized earlobe**

• Potential for reduced wrist mobility

physicians and specialist nurses are able

Use in research circumstances is limited by the need for a physician to be available to carry out the technique

*Comparison between the characteristics of radial artery puncture and blood collection from the arterialized* 

*DOI: http://dx.doi.org/10.5772/intechopen.93469*

then be analyzed using a standard blood analyzer [1, 3–6].

the feasibility of performing this technique in space missions.

the neck, with the volunteer in the supine position.

• Haematoma formation

to carry out this procedure

only by trained personnel

• Hemorrhage • Infection

• Nerve damage

Potential usages Currently used in hospital setting but

Ease of use Requires training: currently only

## *A Device for Sampling Earlobe Arterialized Blood in Space and Other Austere Environments DOI: http://dx.doi.org/10.5772/intechopen.93469*

importance; therefore, if the earlobe is not hyperaemic after 4 minutes of preparation, massage or heating should continue. Conventionally, the skin of the earlobe is cleaned with alcohol, and a puncture, 2–4 mm deep, is made with a sterile blade. The blood is collected in a heparinized capillary tube or cartridge, which is held in such a way that the blood enters anaerobically by capillary action. This blood can then be analyzed using a standard blood analyzer [1, 3–6].

**Table 1** summarizes the differences between the two techniques of blood collection via arterial puncture and blood collection from an arterialized earlobe.

## **2.2 Earlobe arterialized blood technique in microgravity simulation studies**

A series of studies were conducted at King's College London, as part of the PhD thesis entitled 'The effect of 3h of 6-degree Head-Down Tilt (HDT) with and without hypoxia and light exercise on lung function' [7], with the aim of evaluating the feasibility of performing this technique in space missions.

There was first the need to establish whether the lower to upper body redistribution of blood that occurs during microgravity exposure, with the subsequent venous congestion of the face and neck of astronauts, could cause contamination of the arterial blood from venous blood, thereby affecting results. The arterialized capillary blood sample technique had not been used previously during groundbased microgravity simulations, parabolic flights or space missions, and therefore, a preliminary study was designed to evaluate the possible effect of the head congestion on the gas tensions of earlobe arterialized blood samples. In order to avoid the cardiopulmonary changes associated with tilting to the 6° head-down position, the ground-based microgravity simulation used, the increase in venous pressure in the earlobe associated with this position was reproduced by inflating a cuff around the neck, with the volunteer in the supine position.

The venous pressure at the earlobe was calculated as the change in the vertical height of the ear relative to the heart on transition from supine to 6° head-down. Assuming a 30 cm distance between the earlobe and the right atrium, the increase


#### **Table 1.**

*Preparation of Space Experiments*

surviving the stresses caused by a space rocket launch.

**2. Validation of the arterialized blood technique**

**2.1 Arterialized versus arterial blood**

unsuitable for use in this scenario.

blood is collected [2].

as in space missions [2].

The utility of finding a solution to this problem is not in doubt. Physiological findings could be confirmed with greater accuracy and more detailed studies conducted in the future. Clinical emergencies could also be managed with greater facility, resulting in increased safety for all crew involved in space missions. To this end, the arterialized earlobe blood collection technique for evaluating blood gas tensions has been considered for use in space, as analyses of the blood obtained could provide valuable information regarding the diagnosis of a number of medical conditions. This technique was first developed in 1944 and adopted under certain circumstances as an alternative to arterial puncture and arterial cannulation [1]. Nonetheless, the current earlobe arterialized blood collection technique is untested in microgravity, as is the risk of contamination of the environment with blood droplets. Therefore, a series of researches and tests have taken place to validate the suitability of the arterialized blood as an analogue of arterial blood and its suitability for use in microgravity, the creation of an easy-to-use and safe device for collecting arterialized blood from the earlobe, validating its use in ground-based studies on Earth and in microgravity, and determining the space preparedness of the device for

Arterial gas analyses are essential for the clinical evaluation of astronauts, since they provide important physiologic information and can be an important tool for performing disease diagnoses during a space mission. However, currently available devices and methods, such as puncture and cannulation of an artery, are considered

Arterial cannulation, the positioning of an intra-arterial catheter, is a technique which allows continuous and direct monitorization of blood pressure and frequent sample withdrawal for blood analyses. Arterial blood by means of puncture is usually collected from the wrist or from the inner part of the elbow or other arteries, through the insertion of a needle in a previously cleaned area. The blood then flows into a heparinized syringe, and the needle is removed as soon as enough

Both arterial cannulation and puncture are known to be difficult techniques to perform, requiring specialist training, causing pain to the patient and having the possibility of contamination of the environment with blood droplets. Moreover, although low, there is an increased risk of serious complications, such as haematoma, excessive bleeding and infection. Therefore, it is well accepted that the direct sampling of arterial blood is unsuitable for use in many austere environments, such

The earlobe arterialized blood technique makes use of the fact that the capillary blood taken from the arterialized earlobe originates from the arterioles and thus has the composition of arterial blood. The technique has been available as a substitute for arterial puncture for more than 60 years in clinical medicine and physiological research. The success of the technique depends upon careful preparation of the earlobe, which is arterialized by rendering it hyperaemic. This can be executed by heating the earlobe or massaging it with a rubefacient cream, thus ensuring free flow of blood from any incision made. The time of preparation varies from study to study, though conventionally it ranges from 3 to 10 minutes, with the standard being around 4 minutes. Ensuring adequate vasodilatation is of primary

**158**

*Comparison between the characteristics of radial artery puncture and blood collection from the arterialized earlobe.*

in hydrostatic pressure at the ear was 2.3 mmHg.1 The increase in central venous pressure secondary to the headward shift of the blood during head-down tilt was of the order of 3 [8] to 5 mmHg [9], resulting in a total increase in venous pressure on moving from the horizontal to 6° HDT ranging from 5.3 to 8.3 mmHg. Therefore, a neck cuff pressure of 10 mmHg was adopted for the study, which would produce a slightly greater degree of venous congestion of the ear.

The research evaluated seven healthy volunteers, aged 21–36 years. Each volunteer laid supine on a couch and completed three phases of 10 min each, divided into baseline (neck cuff deflated, control), test (neck cuff inflated) and recovery (neck cuff deflated, recovery). During each phase, the respired gases at the lips were sampled continuously, using O2 and CO2 rapid response gas analysers, from which their outputs were recorded and used to calculate respiratory frequency, end-tidal PO2 (partial pressure of O2) and PCO2 (partial pressure of CO2). Two earlobe arterialized blood samples were collected during the last 2 min of each phase, and the PO2 and PCO2 were determined using the pH/blood gas analyser. During the performance of the earlobe blood collection, no participant showed apprehension or distress, and there were no reports of complication (skin infection or bleeding) after the completion of the experiment. The healing of the incision was well advanced 72 h following the procedures. These findings are in accordance with those of Spiro and Dowdeswell [10], who found the arterialized earlobe technique to have no morbidity and to be virtually pain-free.

The means (±standard deviation, SD) of the respiratory frequency, end-tidal PO2 and PCO2, earlobe arterialized blood PO2 and PCO2 and the end-tidal minus earlobe arterialized blood PO2 and PCO2 differences before, during (test phase) and after inflation of the neck cuff are presented in **Table 2**.

The findings of this study showed no significant differences in the mean values of respiratory frequency, end-tidal PO2 and PCO2 and earlobe arterialized blood PO2 and PCO2 between the three phases. During the baseline, test and recovery phases, the end-tidal minus earlobe arterialized blood PO2 and PCO2 differences were 7.4 (±2.8) and 1.0 (±0.9), 7.7 (±4.3) and −0.5 (±1.4) and 7.7 (±3.3) and −0.6 (±1.0), respectively. The mean values of the differences found in this study are very similar to those reported in the literature for healthy volunteers breathing air at rest [11, 12].

The findings of this study were very important, as it demonstrated that congestion of the head did not affect the PO2 and PCO2 of the arterialized blood taken from the earlobe and the end-tidal arterialized blood differences. Therefore, it is possible to state that raising the venous pressure in the head by 10 mmHg, used to simulate the venous congestion encountered during microgravity exposure, did not cause any deleterious effect on the relationship between the PO2 and PCO2 of the arterialized blood sampled from the earlobe and the PO2 and PCO2 of the systemic arterial blood [7, 13, 14].

A second experiment was then designed within the scope of the same PhD thesis [7] to further understand the effects of HDT on the earlobe arterialized blood method. Therefore, hypoxia was added to the ground-based microgravity simulation in order to create an extra stressor. The differences between the tensions of oxygen and carbon dioxide in the end-tidal gas and earlobe arterialized blood were examined under two experimental conditions: breathing air (normoxia) and breathing a mixture of 10.7% O2 in N2, which is equivalent to breathing air at an altitude of 16,000 feet2 (hypoxia).

**161**

*A Device for Sampling Earlobe Arterialized Blood in Space and Other Austere Environments*

RF (br/min) 13.1 ± 2.1 13.0 ± 2.2 13.0 ± 2.2 PETO2 (mmHg) 103.6 ± 3.3 107.2 ± 8.7 101.6 ± 5.0 PabO2 (mmHg) 96.2 ± 2.5 99.7 ± 7.1 93.9 ± 3.7 PETCO2 (mmHg) 38.2 ± 4.0 37.8 ± 4.1 38.2 ± 4.1 PabCO2 (mmHg) 38.0 ± 4.0 38.5 ± 4.0 38.8 ± 3.7 PET-ab O2 (mmHg) 7.4 ± 2.8 7.7 ± 4.3 7.7 ± 3.3 PET-ab CO2 (mmHg) 1.0 ± 0.9 −0.5 ± 1.4 −0.6 ± 1.0

**Baseline mean (±SD) Test mean (±SD) Recovery mean (±SD)**

A system was designed for this experiment permitting volunteers to breathe the inspired gas mixture through an oronasal mask. The normoxic gas (air) was supplied to the volunteer from a compressed air cylinder, and the hypoxic gas mixture was produced by mixing appropriate flows of air and nitrogen. The gases were mixed in a 100 L Douglas bag, before being delivered to the participant. The concentration of oxygen in the bag was monitored at 1 min intervals throughout the experiment. The following safety procedures were put in place: a source of 100% O2 was connected to the gas supply, and the concentration of oxygen in the inspired gas was monitored with an oxygen rapid response gas analyser (alarm set to operate at 10.2% O2). Arterial oxygen saturation (alarm set to operate at 65%) by means of pulse oximeter and blood pressure and heart rate were continuously monitored with a Finapres device. The ability of the volunteer to respond to simple commands was assessed every 2 min in order to identify any deleterious effect of hypoxia on

*The effect of inflation of a neck cuff (test) on respiratory frequency (RF, breath/minute), end-tidal PO2 (PETO2) and PCO2 (PETCO2), earlobe arterialized blood PO2 (PabO2) and PCO2 (PabCO2) and end-tidal* 

*minus earlobe arterialized blood PO2 (PET-ab O2) and PCO2 (PET-ab CO2) differences.*

Six healthy volunteers, aged 21–26 years, participated in the experiment and were not informed as to whether they were breathing air or the hypoxic mixture until the study was complete. The experiment began with the tilt table placed horizontally, and the individual was asked to lie in the supine position for 30 min (rest period). They were then placed into the required position (either supine or 6° HDT), wearing an oronasal mask and breathing the gas supply (either 20.9% O2 or 10.7% O2) for 20 min. For the final 10 min, the oronasal mask was replaced with a mouthpiece, a valve box and a nose clip, the earlobe was arterialized using massage and a vasodilating cream, and two earlobe blood samples were collected. The PO2 and PCO2 of the blood samples were immediately determined by means of the pH/ blood gas analyser. End-tidal PO2 and PCO2 were continuously analyzed via the gas

All volunteers completed the study without any untoward effects. The means of the end-tidal PO2 and PCO2, the earlobe arterialized blood PO2 and PCO2 and the end-tidal minus earlobe arterialized blood PO2 and PCO2 differences for each body

End-tidal PO2 and earlobe arterialized blood PO2 decreased, as expected, from approximately 103 and 94 mmHg during normoxia to 40 and 36 mmHg during hypoxia, respectively, for both positions together (p < 0.05). The PET-abO2, consequently, also decreased from a combined mean of 9.6 mmHg during normoxia to a mean of 3.4 mmHg during hypoxia (p < 0.05). The mean end-tidal and earlobe arterialized capillary PCO2 decreased (p < 0.05) during hypoxia in comparison

*DOI: http://dx.doi.org/10.5772/intechopen.93469*

**Table 2.**

mental performance and cognition.

analysers and recorded during the last 10 minutes.

position during normoxia and hypoxia are presented in **Table 3**.

<sup>1</sup> A pressure of 1 mmHg corresponds approximately to 1.33 mbar.

<sup>2</sup> Equivalent to 4876.8 m


*A Device for Sampling Earlobe Arterialized Blood in Space and Other Austere Environments DOI: http://dx.doi.org/10.5772/intechopen.93469*

#### **Table 2.**

*Preparation of Space Experiments*

in hydrostatic pressure at the ear was 2.3 mmHg.1

slightly greater degree of venous congestion of the ear.

to have no morbidity and to be virtually pain-free.

after inflation of the neck cuff are presented in **Table 2**.

(hypoxia).

<sup>1</sup> A pressure of 1 mmHg corresponds approximately to 1.33 mbar.

pressure secondary to the headward shift of the blood during head-down tilt was of the order of 3 [8] to 5 mmHg [9], resulting in a total increase in venous pressure on moving from the horizontal to 6° HDT ranging from 5.3 to 8.3 mmHg. Therefore, a neck cuff pressure of 10 mmHg was adopted for the study, which would produce a

The research evaluated seven healthy volunteers, aged 21–36 years. Each volunteer laid supine on a couch and completed three phases of 10 min each, divided into baseline (neck cuff deflated, control), test (neck cuff inflated) and recovery (neck cuff deflated, recovery). During each phase, the respired gases at the lips were sampled continuously, using O2 and CO2 rapid response gas analysers, from which their outputs were recorded and used to calculate respiratory frequency, end-tidal PO2 (partial pressure of O2) and PCO2 (partial pressure of CO2). Two earlobe arterialized blood samples were collected during the last 2 min of each phase, and the PO2 and PCO2 were determined using the pH/blood gas analyser. During the performance of the earlobe blood collection, no participant showed apprehension or distress, and there were no reports of complication (skin infection or bleeding) after the completion of the experiment. The healing of the incision was well advanced 72 h following the procedures. These findings are in accordance with those of Spiro and Dowdeswell [10], who found the arterialized earlobe technique

The means (±standard deviation, SD) of the respiratory frequency, end-tidal PO2 and PCO2, earlobe arterialized blood PO2 and PCO2 and the end-tidal minus earlobe arterialized blood PO2 and PCO2 differences before, during (test phase) and

The findings of this study showed no significant differences in the mean values of respiratory frequency, end-tidal PO2 and PCO2 and earlobe arterialized blood PO2 and PCO2 between the three phases. During the baseline, test and recovery phases, the end-tidal minus earlobe arterialized blood PO2 and PCO2 differences were 7.4 (±2.8) and 1.0 (±0.9), 7.7 (±4.3) and −0.5 (±1.4) and 7.7 (±3.3) and −0.6 (±1.0), respectively. The mean values of the differences found in this study are very similar to those reported in the literature for healthy volunteers breathing air

The findings of this study were very important, as it demonstrated that congestion of the head did not affect the PO2 and PCO2 of the arterialized blood taken from the earlobe and the end-tidal arterialized blood differences. Therefore, it is possible to state that raising the venous pressure in the head by 10 mmHg, used to simulate the venous congestion encountered during microgravity exposure, did not cause any deleterious effect on the relationship between the PO2 and PCO2 of the arterialized blood sampled from the earlobe and the PO2 and PCO2 of the systemic

A second experiment was then designed within the scope of the same PhD thesis [7] to further understand the effects of HDT on the earlobe arterialized blood method. Therefore, hypoxia was added to the ground-based microgravity simulation in order to create an extra stressor. The differences between the tensions of oxygen and carbon dioxide in the end-tidal gas and earlobe arterialized blood were examined under two experimental conditions: breathing air (normoxia) and breathing a mixture of 10.7% O2 in N2, which is equivalent to breathing air at an

The increase in central venous

**160**

at rest [11, 12].

arterial blood [7, 13, 14].

altitude of 16,000 feet2

<sup>2</sup> Equivalent to 4876.8 m

*The effect of inflation of a neck cuff (test) on respiratory frequency (RF, breath/minute), end-tidal PO2 (PETO2) and PCO2 (PETCO2), earlobe arterialized blood PO2 (PabO2) and PCO2 (PabCO2) and end-tidal minus earlobe arterialized blood PO2 (PET-ab O2) and PCO2 (PET-ab CO2) differences.*

A system was designed for this experiment permitting volunteers to breathe the inspired gas mixture through an oronasal mask. The normoxic gas (air) was supplied to the volunteer from a compressed air cylinder, and the hypoxic gas mixture was produced by mixing appropriate flows of air and nitrogen. The gases were mixed in a 100 L Douglas bag, before being delivered to the participant. The concentration of oxygen in the bag was monitored at 1 min intervals throughout the experiment. The following safety procedures were put in place: a source of 100% O2 was connected to the gas supply, and the concentration of oxygen in the inspired gas was monitored with an oxygen rapid response gas analyser (alarm set to operate at 10.2% O2). Arterial oxygen saturation (alarm set to operate at 65%) by means of pulse oximeter and blood pressure and heart rate were continuously monitored with a Finapres device. The ability of the volunteer to respond to simple commands was assessed every 2 min in order to identify any deleterious effect of hypoxia on mental performance and cognition.

Six healthy volunteers, aged 21–26 years, participated in the experiment and were not informed as to whether they were breathing air or the hypoxic mixture until the study was complete. The experiment began with the tilt table placed horizontally, and the individual was asked to lie in the supine position for 30 min (rest period). They were then placed into the required position (either supine or 6° HDT), wearing an oronasal mask and breathing the gas supply (either 20.9% O2 or 10.7% O2) for 20 min. For the final 10 min, the oronasal mask was replaced with a mouthpiece, a valve box and a nose clip, the earlobe was arterialized using massage and a vasodilating cream, and two earlobe blood samples were collected. The PO2 and PCO2 of the blood samples were immediately determined by means of the pH/ blood gas analyser. End-tidal PO2 and PCO2 were continuously analyzed via the gas analysers and recorded during the last 10 minutes.

All volunteers completed the study without any untoward effects. The means of the end-tidal PO2 and PCO2, the earlobe arterialized blood PO2 and PCO2 and the end-tidal minus earlobe arterialized blood PO2 and PCO2 differences for each body position during normoxia and hypoxia are presented in **Table 3**.

End-tidal PO2 and earlobe arterialized blood PO2 decreased, as expected, from approximately 103 and 94 mmHg during normoxia to 40 and 36 mmHg during hypoxia, respectively, for both positions together (p < 0.05). The PET-abO2, consequently, also decreased from a combined mean of 9.6 mmHg during normoxia to a mean of 3.4 mmHg during hypoxia (p < 0.05). The mean end-tidal and earlobe arterialized capillary PCO2 decreased (p < 0.05) during hypoxia in comparison


#### **Table 3.**

*Mean end-tidal PO2 and PCO2 (PET), earlobe arterialized blood PO2 and PCO2 (Pab) and end-tidal minus earlobe arterialized blood PO2 and PCO2 differences (PET-ab) during normoxia (N) and hypoxia (H) for 6° HDT and supine positions.*

with normoxia in both positions, due to hyperventilation secondary to the low arterial PO2. There were no significant differences between the values of end-tidal, arterialized blood and end-tidal minus earlobe arterialized blood differences for PO2 and PCO2 when the two positions were compared during either normoxia or hypoxia.

These findings led to the conclusion that the 6° HDT position did not alter the end-tidal minus earlobe arterialized blood PO2 and PCO2 differences from those obtained in the supine position during either normoxia or hypoxia, which reinforces the belief that this technique is suitable for use in either ground-based microgravity studies or in space missions.

## **3. Development and validation of an earlobe arterialized blood collector (EABC) device**

The previously presented two studies were pioneering, as they were the first to be conducted during HDT using the earlobe arterialized blood collection technique. It was demonstrated that this technique is feasible for application in space missions or for physiological studies during microgravity simulation on Earth; however, the technique has the possibility of causing contamination of the environment to take place. This could be of major concern, especially in a spacecraft or space station, as blood droplets in microgravity would float with the potential to contaminate fellow astronauts or equipment. Taking this into consideration, a self-contained device was developed that would permit a standardized sampling of earlobe arterialized blood to be safely collected in a microgravity environment by non-medical personnel and without discomfort to the volunteer. The device was developed by the Microgravity Centre in collaboration with IDEIA Institute, both from the Pontifical Catholic University of Rio Grande do Sul, Brazil.

### **3.1 Evolution of the earlobe arterialized blood collector**

The vision for the design of the earlobe arterialized blood collector was to develop a device with the following properties:

• Able to produce a suitable incision in the earlobe, such that sufficient flow of blood ensues to allow rapid and easy blood collection.

**163**

**Figure 1.**

*A Device for Sampling Earlobe Arterialized Blood in Space and Other Austere Environments*

• The incision should be relatively pain-free and as accurate in depth and

• Capillary tubes or cartridges should provide anaerobic blood collection, through being positioned easily, quickly and precisely over the incision made and reducing the potential for contamination of the environment or any other

• The device itself should be easy to use in terrestrial, aviation and extraterres-

• The device must be easy to apply and remove from the earlobe, allowing quick application of gauze or a similar material to the incision to promote

The first prototype was constructed in 1999, being 583 g in weight, 102 mm in length and 40 mm in diameter. This first prototype was mainly used to test the concept, and some earlobe arterialized blood collections were performed to evaluate the ability of the EABC to perform the cut and collect blood anaerobically, provid-

The proof-of-concept success of this first EABC design led to its continued development, with a series of seven devices evolving over a 10-year period, leading to changes and improvements in shape, size, weight and used proce-

**Figure 2** illustrates the first four generations in the developmental process of the

The technique of blood collection is demonstrated in the sequence of six pictures in **Figure 3**, which shows the earlobe arterialization procedure with massage and a vasodilating cream, cleaning of the earlobe skin, placement of the EABC with a cartridge, blood collection and analysis in an i-STAT blood analyser device (Abbott

trial environments, with minimal training (user-friendly).

• The device must be small, lightweight, disposable and low-cost.

ing expected arterial gases results from a healthy volunteer (**Figure 1**).

position as possible (in as far as these two variables should be predictable and

*DOI: http://dx.doi.org/10.5772/intechopen.93469*

easily adjustable).

part of the device.

rapid hemostasis.

dures (**Table 4**).

EABC and the final EABC device.

*First earlobe arterialized blood result using the first version EABC.*

Point of Care Inc., Brazil).

*A Device for Sampling Earlobe Arterialized Blood in Space and Other Austere Environments DOI: http://dx.doi.org/10.5772/intechopen.93469*


The first prototype was constructed in 1999, being 583 g in weight, 102 mm in length and 40 mm in diameter. This first prototype was mainly used to test the concept, and some earlobe arterialized blood collections were performed to evaluate the ability of the EABC to perform the cut and collect blood anaerobically, providing expected arterial gases results from a healthy volunteer (**Figure 1**).

The proof-of-concept success of this first EABC design led to its continued development, with a series of seven devices evolving over a 10-year period, leading to changes and improvements in shape, size, weight and used procedures (**Table 4**).

**Figure 2** illustrates the first four generations in the developmental process of the EABC and the final EABC device.

The technique of blood collection is demonstrated in the sequence of six pictures in **Figure 3**, which shows the earlobe arterialization procedure with massage and a vasodilating cream, cleaning of the earlobe skin, placement of the EABC with a cartridge, blood collection and analysis in an i-STAT blood analyser device (Abbott Point of Care Inc., Brazil).

**Figure 1.** *First earlobe arterialized blood result using the first version EABC.*

*Preparation of Space Experiments*

**PETO2 mean (±SD)**

*Different from normoxia; p < 0.05. All pressures in mmHg.*

**PabO2 mean (±SD)**

**PET-abO2 mean (±SD)**

Supine, N 101.6 ± 8.8 92.7 ± 8.9 8.9 ± 2.9 43.6 ± 2.9 42.8 ± 3.2 0.77 ± 2.4 6° HDT, N 105.6 ± 4.0 95.4 ± 4.5 10.3 ± 4.0 42.1 ± 2.5 41.9 ± 3.7 0.13 ± 2.4 Supine, H 40.9 ± 4.5\* 36.5 ± 3.3\* 4.7 ± 1.8\* 37.7 ± 3.3\* 35.7 ± 3.0\* 2.1 ± 3.4\* 6° HDT, H 40.8 ± 3.8\* 36.9 ± 4.6\* 2.1 ± 3.4\* 35.8 ± 3.8\* 34.3 ± 5.2\* 1.4 ± 3.0\*

**PETCO2 mean (±SD)**

**PabCO2 mean (±SD)**

**PET-abCO2 mean (±SD)**

hypoxia.

*\**

**Table 3.**

*HDT and supine positions.*

microgravity studies or in space missions.

**(EABC) device**

Grande do Sul, Brazil.

**3.1 Evolution of the earlobe arterialized blood collector**

blood ensues to allow rapid and easy blood collection.

develop a device with the following properties:

with normoxia in both positions, due to hyperventilation secondary to the low arterial PO2. There were no significant differences between the values of end-tidal, arterialized blood and end-tidal minus earlobe arterialized blood differences for PO2 and PCO2 when the two positions were compared during either normoxia or

*Mean end-tidal PO2 and PCO2 (PET), earlobe arterialized blood PO2 and PCO2 (Pab) and end-tidal minus earlobe arterialized blood PO2 and PCO2 differences (PET-ab) during normoxia (N) and hypoxia (H) for 6°* 

These findings led to the conclusion that the 6° HDT position did not alter the end-tidal minus earlobe arterialized blood PO2 and PCO2 differences from those obtained in the supine position during either normoxia or hypoxia, which reinforces the belief that this technique is suitable for use in either ground-based

**3. Development and validation of an earlobe arterialized blood collector** 

The previously presented two studies were pioneering, as they were the first to be conducted during HDT using the earlobe arterialized blood collection technique. It was demonstrated that this technique is feasible for application in space missions or for physiological studies during microgravity simulation on Earth; however, the technique has the possibility of causing contamination of the environment to take place. This could be of major concern, especially in a spacecraft or space station, as blood droplets in microgravity would float with the potential to contaminate fellow astronauts or equipment. Taking this into consideration, a self-contained device was developed that would permit a standardized sampling of earlobe arterialized blood to be safely collected in a microgravity environment by non-medical personnel and without discomfort to the volunteer. The device was developed by the Microgravity Centre in collaboration with IDEIA Institute, both from the Pontifical Catholic University of Rio

The vision for the design of the earlobe arterialized blood collector was to

• Able to produce a suitable incision in the earlobe, such that sufficient flow of

**162**

#### *Preparation of Space Experiments*


#### **Table 4.**

*Main characteristics of the seven versions of the EABC.*

**Figure 2.** *Evolution of the EABC—First four generations on the left and the seventh EABC device on the right.*

## **3.2 Preliminary EABC validation study**

An initial EABC validation research was conducted involving six healthy volunteer students from King's College London, using the second EABC prototype (**Figure 4**) [15, 16].

An 8° HDT was used as a microgravity simulator in combination with hypoxia, equivalent to breathing air at 12,000 ft.3 Blood samples were collected from the radial artery of volunteers and simultaneously from their arterialized earlobe, after being in the HDT position and breathing a 12.8% O2 in N2 mix for 15 min (**Figures 5** and **6**).

The arterialization procedure involved first rendering the earlobe hyperaemic by the application of a rubefacient cream, massaged into the earlobe for a period of 5 minutes. The skin was then cleaned using an alcohol swab and dried with sterile gauze and the second version of the EABC attached to the earlobe. An incision was made in the earlobe and samples of blood collected in the two capillary tubes of the second version of the EABC, simultaneously with the drawing of a 2 mL sample of blood from the radial artery into a syringe lubricated with heparin solution (5000 IU/mL4 ).

The PO2, PCO2 and pH of the blood samples were determined immediately using a blood gas analyser (Ciba Corning 238 pH/blood gas analyser, Ciba Corning

**165**

**Figure 3.**

the results of the blood analyses.

*EG7 cartridge in the i-STAT device.*

*A Device for Sampling Earlobe Arterialized Blood in Space and Other Austere Environments*

Diagnostics Ltd., Halstead, Essex). The mean differences (±SD) in PO2 between earlobe arterialized and radial artery blood samples were 0.25 ± 1.25 mmHg for PO2 and 1.0 ± 0.75 mmHg for CO2; neither difference was significant. There was no difference between the pH values obtained by the two techniques. **Table 5** summarizes

*Sequence of six pictures showing the earlobe arterialized blood collection and subsequent analysis, placing the* 

All EABC clinical studies were funded by the European Space Agency via the Medical Projects and Technology Unit from the Crew Medical Support Office,

The physiological studies performed during microgravity simulation suggested that the arterialized blood sampled from the earlobe using the EABC may provide sufficiently accurate measurements of the PO2, PCO2 and pH of the arterial blood

**3.3 Clinical evaluation of the EABC in haemodialysis patients**

European Astronaut Centre, Cologne, Germany.

*DOI: http://dx.doi.org/10.5772/intechopen.93469*

<sup>3</sup> Equivalent to 3657.6 m

<sup>4</sup> Heparin is a medication used as an anticoagulant (blood thinner). One unit of heparin is an amount approximately equivalent to 0.002 mg of pure heparin, which is the quantity required to keep 1 ml of cat's blood fluid for 24 hours at 0°C.

*A Device for Sampling Earlobe Arterialized Blood in Space and Other Austere Environments DOI: http://dx.doi.org/10.5772/intechopen.93469*

*Preparation of Space Experiments*

**164**

**Figure 2.**

**Table 4.**

(**Figure 4**) [15, 16].

<sup>3</sup> Equivalent to 3657.6 m

cat's blood fluid for 24 hours at 0°C.

**3.2 Preliminary EABC validation study**

*Main characteristics of the seven versions of the EABC.*

equivalent to breathing air at 12,000 ft.3

*Evolution of the EABC—First four generations on the left and the seventh EABC device on the right.*

An initial EABC validation research was conducted involving six healthy volunteer students from King's College London, using the second EABC prototype

An 8° HDT was used as a microgravity simulator in combination with hypoxia,

**Version Dimensions L × Ø (mm) Weight (g) Blade model Blood recipient** 102 × 94 583 No 11 Capillary tube 138 × 40 228 No 11 Capillary tube 107 × 27 85 Adapted No 11 Capillary tube 104 × 26 42 Adapted No 15° Capillary tube 90 × 23 18 Ophthalmic blade Without cartridge 57 × 26 (55 including cartridge) 29.5 Ophthalmic blade I-STAT cartridge 73 × 26 (55 including cartridge) 28.2 Ophthalmic blade I-STAT cartridge

artery of volunteers and simultaneously from their arterialized earlobe, after being in the HDT position and breathing a 12.8% O2 in N2 mix for 15 min (**Figures 5** and **6**). The arterialization procedure involved first rendering the earlobe hyperaemic by the application of a rubefacient cream, massaged into the earlobe for a period of 5 minutes. The skin was then cleaned using an alcohol swab and dried with sterile gauze and the second version of the EABC attached to the earlobe. An incision was made in the earlobe and samples of blood collected in the two capillary tubes of the second version of the EABC, simultaneously with the drawing of a 2 mL sample of blood from the

radial artery into a syringe lubricated with heparin solution (5000 IU/mL4

The PO2, PCO2 and pH of the blood samples were determined immediately using a blood gas analyser (Ciba Corning 238 pH/blood gas analyser, Ciba Corning

<sup>4</sup> Heparin is a medication used as an anticoagulant (blood thinner). One unit of heparin is an amount approximately equivalent to 0.002 mg of pure heparin, which is the quantity required to keep 1 ml of

Blood samples were collected from the radial

).

#### **Figure 3.**

*Sequence of six pictures showing the earlobe arterialized blood collection and subsequent analysis, placing the EG7 cartridge in the i-STAT device.*

Diagnostics Ltd., Halstead, Essex). The mean differences (±SD) in PO2 between earlobe arterialized and radial artery blood samples were 0.25 ± 1.25 mmHg for PO2 and 1.0 ± 0.75 mmHg for CO2; neither difference was significant. There was no difference between the pH values obtained by the two techniques. **Table 5** summarizes the results of the blood analyses.

## **3.3 Clinical evaluation of the EABC in haemodialysis patients**

All EABC clinical studies were funded by the European Space Agency via the Medical Projects and Technology Unit from the Crew Medical Support Office, European Astronaut Centre, Cologne, Germany.

The physiological studies performed during microgravity simulation suggested that the arterialized blood sampled from the earlobe using the EABC may provide sufficiently accurate measurements of the PO2, PCO2 and pH of the arterial blood

**167**

**Figure 7.**

*being performed with a caliper.*

*A Device for Sampling Earlobe Arterialized Blood in Space and Other Austere Environments*

**Radial artery Mean ± SD (range)**

pH 7.43 ± 0.02 (7.4–7.46) 7.43 ± 0.02 (7.4–7.46) PO2 (mmHg) 42.1 ± 3.66 (38–47) 42.9 ± 3.88 (37–50) PCO2 (mmHg) 34.1 ± 1.88 (31–37) 33.12 ± 2.38 (29–37) SaO2 (%) 79 ± 3.85 (75–84.5) 79.9 ± 3.29 (74–85.6)

for clinical or research use in extreme environments, such as space. However, another important step would be to also evaluate the use of the EABC in a clinical setting on Earth, as technology transfer from space to terrestrial application was

*Blood gas data for simultaneous radial artery and earlobe arterialized blood samples collected using the EABC.*

With this in mind, a first clinical study was conducted involving 12 patients from a hemodialysis clinic, meaning these individuals already had a medically determined need for measurement of arterial blood parameters, including arterial blood gas tensions and acid–base variables, and access to arterial blood was easily provided by an already existing fistula. The main goal was to compare arterial blood variables taken from the arterial side of the arterial–venous fistula with those obtained from the earlobe arterialized blood collected using the seventh version of the EABC. Blood collection was achieved simultaneously from the fistula and the arterialized earlobe in an i-STAT EC8+ cartridge, and the two samples were analyzed using a portable

one of the aims for the use of this pioneering technology.

i-STAT blood analyser device (Abbott Point-of-care Inc., Brazil) [17].

samples ranged from 0.006 (for pH) to 2.8 mg/dL (for glucose). The R<sup>2</sup>

ence, whilst the 4 that were significantly different (BUN, Cl<sup>−</sup>, K<sup>+</sup>

or above 0.93 in 10 of the 13 blood variables measured, and the lowest R<sup>2</sup>

PCO2 (0.68). Of the 13 blood measurements, 9 presented no significant differ-

their values within normality, presented no clinical implication and did not affect

*Schematic view of the difference between cut length and blade movement profile (left) and cut measurement* 

In addition to blood parameters, earlobe incision length and subject pain perception were also evaluated. Incision length (mm) was measured with a caliper immediately after blood collection, and the patient pain perception was assessed, using a scale from 0 (no pain) to 10 (maximum perceived pain). **Figure 7** shows a schematic view of the earlobe cut and its measurement during the experiment.

The mean of the differences obtained from the earlobe arterialized and arterial

was equal

was for

, anion gap) had

**Arterialized earlobe Mean ± SD (range)**

*DOI: http://dx.doi.org/10.5772/intechopen.93469*

**Table 5.**

**Figure 4.** *Characteristics of the second EABC version.*

**Figure 5.** *Volunteer in HDT whilst breathing the hypoxic mixture.*

#### **Figure 6.**

*Example of data being recorded during the beginning of hypoxic exposure (12.8% O2 in N2, equivalent to breathing air at 12,000 ft3 ).*

*A Device for Sampling Earlobe Arterialized Blood in Space and Other Austere Environments DOI: http://dx.doi.org/10.5772/intechopen.93469*


**Table 5.**

*Preparation of Space Experiments*

*Characteristics of the second EABC version.*

**Figure 4.**

**166**

**Figure 6.**

**Figure 5.**

*breathing air at 12,000 ft3*

*).*

*Volunteer in HDT whilst breathing the hypoxic mixture.*

*Example of data being recorded during the beginning of hypoxic exposure (12.8% O2 in N2, equivalent to* 

*Blood gas data for simultaneous radial artery and earlobe arterialized blood samples collected using the EABC.*

for clinical or research use in extreme environments, such as space. However, another important step would be to also evaluate the use of the EABC in a clinical setting on Earth, as technology transfer from space to terrestrial application was one of the aims for the use of this pioneering technology.

With this in mind, a first clinical study was conducted involving 12 patients from a hemodialysis clinic, meaning these individuals already had a medically determined need for measurement of arterial blood parameters, including arterial blood gas tensions and acid–base variables, and access to arterial blood was easily provided by an already existing fistula. The main goal was to compare arterial blood variables taken from the arterial side of the arterial–venous fistula with those obtained from the earlobe arterialized blood collected using the seventh version of the EABC. Blood collection was achieved simultaneously from the fistula and the arterialized earlobe in an i-STAT EC8+ cartridge, and the two samples were analyzed using a portable i-STAT blood analyser device (Abbott Point-of-care Inc., Brazil) [17].

In addition to blood parameters, earlobe incision length and subject pain perception were also evaluated. Incision length (mm) was measured with a caliper immediately after blood collection, and the patient pain perception was assessed, using a scale from 0 (no pain) to 10 (maximum perceived pain). **Figure 7** shows a schematic view of the earlobe cut and its measurement during the experiment.

The mean of the differences obtained from the earlobe arterialized and arterial samples ranged from 0.006 (for pH) to 2.8 mg/dL (for glucose). The R<sup>2</sup> was equal or above 0.93 in 10 of the 13 blood variables measured, and the lowest R<sup>2</sup> was for PCO2 (0.68). Of the 13 blood measurements, 9 presented no significant difference, whilst the 4 that were significantly different (BUN, Cl<sup>−</sup>, K<sup>+</sup> , anion gap) had their values within normality, presented no clinical implication and did not affect

#### **Figure 7.**

*Schematic view of the difference between cut length and blade movement profile (left) and cut measurement being performed with a caliper.*

treatment or diagnosis. The mean (±SD) of the earlobe cut length was 4.4 (±1.3) mm, and the patient perceived pain was classified as minor with a mean of 2.7 points out of 10 points.

These findings were very motivating, as they indicated for the first time that the EABC works in a clinical setting and therefore could be considered a method for safe and easy access to arterialized blood sampling for medical diagnoses, not only in space missions but also on Earth. It led to two further studies, which assessed the use of the EABC in more gravely ill hospitalized patients.

#### **3.4 Clinical evaluation of the EABC in critically ill patients**

Two studies were conducted involving critically ill adult patients in intensive care units, aiming to assess the diagnostic and operational capability of the EABC.

A pilot study was first conducted, evaluating the use of the EABC on a cohort of mechanically ventilated adult critically ill patients admitted to an intensive care unit [18]. A comparison was made between the collected arterial blood and earlobe arterialized blood parameters, and the EABC was evaluated for its ability to diagnose acute respiratory distress syndrome (ARDS) in a total of 55 patients.

The results showed a high precision of earlobe arterialized blood samples. The measures of PO2 demonstrated insufficient agreement levels; however, better agreement was seen for PCO2 and pH measurements. The findings of this experiment showed a sensitivity of 100% and specificity of 92.3% for diagnosing ARDS using earlobe arterialized blood gasometric measures.

Sampling with the EABC proved to be unsuccessful in 43.6% of cases, due to insufficient blood flow, although this is not a surprising result given the circumstances of the patients and some important factors must be taken into account. The haemodynamic conditions of critically ill individuals and the use of medications that can cause vasoconstriction can negatively impact on the production of adequate peripheral blood flow. Therefore, the earlobe arterialized blood technique, with or without the use of the EABC, would not seem to be the best alternative for the management of patients in an intensive care unit, though it may prove useful in several clinical conditions and other critical care scenarios, such as emergency rooms, advanced medical transportation and pre-hospital care.

A second study was conceived to perform an operational evaluation of the EABC in critically ill patients [19], looking at aspects such as the number of cuts and cartridges required, ratio of sampling failure and success, bleeding complications and storage requirements. Fifty-five ventilated patients hospitalized in an intensive care unit participated in the study. The findings revealed that researchers took 26 min to obtain blood analysis, broken down into 15 min of patient preparation and 11 min for earlobe arterialized blood sampling and analysis. An average of 1.3 cartridges was required to achieve a successful cut of the earlobe. The results also demonstrated that researchers faced difficulties in performing blood collection in 59% of cases, but only 10% of these problems were reported to be linked to the EABC itself, such as superficial cut, blood leak, collector misalignment and vision obstruction. After the cut was performed, homoeostasis appeared to occur quickly, and no major complications were reported. The study results suggest that the EABC is quick and safe to use and user-friendly.

## **4. Validation of the EABC for space use**

It is critically important that any device to potentially be launched into space must be able to withstand the launch process and spaceflight, remaining

**169**

*A Device for Sampling Earlobe Arterialized Blood in Space and Other Austere Environments*

undamaged. To be considered for use on the International Space Station (ISS) as part of a space mission, the EABC must demonstrate that it can meet the specifications of spaceflight conditions through being submitted to a series of electromechanical tests. The purpose of testing is to expose the EABC to the same circumstances as those encountered during launch onboard a Soyuz rocket and the

The required tests are shock and vibration tests, measurements and mass proprieties, low and high pressure and temperature tests, humidity test and offgassing evaluation [20]. To confirm its suitability for space use, the following tests

• Shock and vibration tests were conducted to check the functionality of the EABC after being launched to the ISS onboard the Soyuz. Two EABCs were placed inside a padded container and attached to a shaker and then submitted

• Measurements and mass proprieties must be known to determine precisely the

• Low- and high-pressure and low- and high-temperature tests were performed to verify the physical and chemical stability of the EABC during variations of

• Humidity test was applied to check the EABC functionality after the changes

• Off-gassing levels were determined as different materials can contaminate the spacecraft ambient air and affect air filters, operation of other equipment and

These tests were conducted at the National Institute for Space Research (INPE), in São José dos Campos, São Paulo, Brazil, with a successful evaluation of the variables tested. The final conclusion of the INPE experts was that the EABC was ready

Having validated the EABC through studies performed in simulated microgravity,

it was important to further validate the earlobe arterialized blood collection technique and device in an actual microgravity scenario. A study was conceived using the fifth EABC prototype (**Figure 8**, this was the prototype available when the proposal was submitted to ESA) to determine if it could effectively be used in the microgravity environment achieved during the free-fall phase of a parabolic flight (42nd ESA Parabolic Flight Campaign in 2006) [21], without contaminating the aircraft envi-

A total of eight healthy participants took part in the ESA parabolic flight campaign, acting as both volunteers and researchers. The blood collections took place inside a hood, especially designed by the Microgravity Centre/PUCRS, Brazil, in order to prevent any possible escape of blood to the aircraft environment. The hood had two openings on three sides for the insertion of two gloved hands each side and a larger opening in the front plastic wall for the volunteer to place their face and

**5. Validation of the earlobe arterialized blood collector for use** 

*DOI: http://dx.doi.org/10.5772/intechopen.93469*

microgravity environment on the ISS.

to different shock and vibration protocols.

mass and centre of gravity of the EABC.

were applied:

such conditions.

in relative humidity.

even astronaut health.

**in microgravity**

ronment with blood products.

to fly in a space mission, as it is space-proof.

## *A Device for Sampling Earlobe Arterialized Blood in Space and Other Austere Environments DOI: http://dx.doi.org/10.5772/intechopen.93469*

undamaged. To be considered for use on the International Space Station (ISS) as part of a space mission, the EABC must demonstrate that it can meet the specifications of spaceflight conditions through being submitted to a series of electromechanical tests. The purpose of testing is to expose the EABC to the same circumstances as those encountered during launch onboard a Soyuz rocket and the microgravity environment on the ISS.

The required tests are shock and vibration tests, measurements and mass proprieties, low and high pressure and temperature tests, humidity test and offgassing evaluation [20]. To confirm its suitability for space use, the following tests were applied:


These tests were conducted at the National Institute for Space Research (INPE), in São José dos Campos, São Paulo, Brazil, with a successful evaluation of the variables tested. The final conclusion of the INPE experts was that the EABC was ready to fly in a space mission, as it is space-proof.

## **5. Validation of the earlobe arterialized blood collector for use in microgravity**

Having validated the EABC through studies performed in simulated microgravity, it was important to further validate the earlobe arterialized blood collection technique and device in an actual microgravity scenario. A study was conceived using the fifth EABC prototype (**Figure 8**, this was the prototype available when the proposal was submitted to ESA) to determine if it could effectively be used in the microgravity environment achieved during the free-fall phase of a parabolic flight (42nd ESA Parabolic Flight Campaign in 2006) [21], without contaminating the aircraft environment with blood products.

A total of eight healthy participants took part in the ESA parabolic flight campaign, acting as both volunteers and researchers. The blood collections took place inside a hood, especially designed by the Microgravity Centre/PUCRS, Brazil, in order to prevent any possible escape of blood to the aircraft environment. The hood had two openings on three sides for the insertion of two gloved hands each side and a larger opening in the front plastic wall for the volunteer to place their face and

*Preparation of Space Experiments*

points out of 10 points.

treatment or diagnosis. The mean (±SD) of the earlobe cut length was 4.4 (±1.3) mm, and the patient perceived pain was classified as minor with a mean of 2.7

use of the EABC in more gravely ill hospitalized patients.

earlobe arterialized blood gasometric measures.

is quick and safe to use and user-friendly.

**4. Validation of the EABC for space use**

rooms, advanced medical transportation and pre-hospital care.

**3.4 Clinical evaluation of the EABC in critically ill patients**

These findings were very motivating, as they indicated for the first time that the EABC works in a clinical setting and therefore could be considered a method for safe and easy access to arterialized blood sampling for medical diagnoses, not only in space missions but also on Earth. It led to two further studies, which assessed the

Two studies were conducted involving critically ill adult patients in intensive care units, aiming to assess the diagnostic and operational capability of the EABC. A pilot study was first conducted, evaluating the use of the EABC on a cohort of mechanically ventilated adult critically ill patients admitted to an intensive care unit [18]. A comparison was made between the collected arterial blood and earlobe arterialized blood parameters, and the EABC was evaluated for its ability to diag-

The results showed a high precision of earlobe arterialized blood samples. The measures of PO2 demonstrated insufficient agreement levels; however, better agreement was seen for PCO2 and pH measurements. The findings of this experiment showed a sensitivity of 100% and specificity of 92.3% for diagnosing ARDS using

Sampling with the EABC proved to be unsuccessful in 43.6% of cases, due to insufficient blood flow, although this is not a surprising result given the circumstances of the patients and some important factors must be taken into account. The haemodynamic conditions of critically ill individuals and the use of medications that can cause vasoconstriction can negatively impact on the production of adequate peripheral blood flow. Therefore, the earlobe arterialized blood technique, with or without the use of the EABC, would not seem to be the best alternative for the management of patients in an intensive care unit, though it may prove useful in several clinical conditions and other critical care scenarios, such as emergency

A second study was conceived to perform an operational evaluation of the EABC in critically ill patients [19], looking at aspects such as the number of cuts and cartridges required, ratio of sampling failure and success, bleeding complications and storage requirements. Fifty-five ventilated patients hospitalized in an intensive care unit participated in the study. The findings revealed that researchers took 26 min to obtain blood analysis, broken down into 15 min of patient preparation and 11 min for earlobe arterialized blood sampling and analysis. An average of 1.3 cartridges was required to achieve a successful cut of the earlobe. The results also demonstrated that researchers faced difficulties in performing blood collection in 59% of cases, but only 10% of these problems were reported to be linked to the EABC itself, such as superficial cut, blood leak, collector misalignment and vision obstruction. After the cut was performed, homoeostasis appeared to occur quickly, and no major complications were reported. The study results suggest that the EABC

It is critically important that any device to potentially be launched into space must be able to withstand the launch process and spaceflight, remaining

nose acute respiratory distress syndrome (ARDS) in a total of 55 patients.

**168**

**Figure 8.** *Fifth version of the EABC.*

be able to breathe, see and talk well. After blood collection, the capillary tube and blood were placed in a hard, human tissue disposal container placed inside the hood at the back (**Figure 9**).

An EABC device was assigned to each of the volunteers, and one or two samples were taken from their earlobes during the 20 s period of microgravity provided by the parabolas. This provided a final study sample of 25 successful earlobe arterialized blood collections in the capillary tubes with a volume of 75 mL (**Figure 10**). Each collection of blood was timed.

The mean (±SD) time for the collection of the arterialized blood from the earlobe during the microgravity phase of the parabolas was 18.9 ± 7.23 s, which was very similar to the time required for the same group of researchers to collect on the ground (mean of 15 s). Researchers reported no difficulties in their ability to handle the EABC under microgravity conditions. It was also observed that no blood products emanated from the EABC, suggesting that the device seals were secure against blood leakage.

The data from this parabolic flight experiment strongly suggests that the arterialized blood from the earlobe can be as effectively sampled using the EABC in microgravity, in much the same way as the blood collections successfully occurred on the ground. Although this first study demonstrated the ability of the EABC to adequately acquire blood in microgravity, the next step required will be to assess the physiological blood variables in the weightlessness phase of a parabolic flight or during the sustained microgravity offered during space missions to ascertain whether this environment will affect such results [22].

**171**

**Author details**

**6. Conclusion**

**Figure 10.**

Thais Russomano1,2

1 InnovaSpace, UK

*A Device for Sampling Earlobe Arterialized Blood in Space and Other Austere Environments*

2 Centre for Human and Applied Physiological Sciences, School of Basic and Medical Biosciences, Faculty of Life Sciences and Medicine, King's College London, UK

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

The earlobe arterialized blood collection was considered for use in space and extreme environments by the author, due to the advantages of the technique, and researches were conducted to evaluate this possibility, with results suggesting it could be applied but at the same time highlighting the chance of blood contamination of the environment. Consequently, a device was developed to prevent this possibility, the earlobe arterialized blood collector, which subsequently underwent a series of tests in simulated microgravity on healthy volunteers and then in clinical practice to also evaluate its potential terrestrial use. Further evaluation was conducted in the microgravity provided by an ESA parabolic flight campaign, and the 'space readiness' of the EABC was assessed through a series of electromechanical tests. In summary, research results suggest the EABC device to be space-proof, easyto-use and low-cost, enabling the collection of arterialized blood as an alternative possibility to arterial puncture/cannulation in the austere environment of space.

\*Address all correspondence to: thais@innovaspace.org

provided the original work is properly cited.

*DOI: http://dx.doi.org/10.5772/intechopen.93469*

*Arterialized blood being collected during parabolic flight.*

*A Device for Sampling Earlobe Arterialized Blood in Space and Other Austere Environments DOI: http://dx.doi.org/10.5772/intechopen.93469*

**Figure 10.** *Arterialized blood being collected during parabolic flight.*

## **6. Conclusion**

*Preparation of Space Experiments*

at the back (**Figure 9**).

*Fifth version of the EABC.*

**Figure 8.**

against blood leakage.

Each collection of blood was timed.

whether this environment will affect such results [22].

be able to breathe, see and talk well. After blood collection, the capillary tube and blood were placed in a hard, human tissue disposal container placed inside the hood

The mean (±SD) time for the collection of the arterialized blood from the earlobe during the microgravity phase of the parabolas was 18.9 ± 7.23 s, which was very similar to the time required for the same group of researchers to collect on the ground (mean of 15 s). Researchers reported no difficulties in their ability to handle the EABC under microgravity conditions. It was also observed that no blood products emanated from the EABC, suggesting that the device seals were secure

The data from this parabolic flight experiment strongly suggests that the arterialized blood from the earlobe can be as effectively sampled using the EABC in microgravity, in much the same way as the blood collections successfully occurred on the ground. Although this first study demonstrated the ability of the EABC to adequately acquire blood in microgravity, the next step required will be to assess the physiological blood variables in the weightlessness phase of a parabolic flight or during the sustained microgravity offered during space missions to ascertain

*Hood system designed to avoid any possible blood contamination of the A300 cabin during the experiment.*

An EABC device was assigned to each of the volunteers, and one or two samples were taken from their earlobes during the 20 s period of microgravity provided by the parabolas. This provided a final study sample of 25 successful earlobe arterialized blood collections in the capillary tubes with a volume of 75 mL (**Figure 10**).

**170**

**Figure 9.**

The earlobe arterialized blood collection was considered for use in space and extreme environments by the author, due to the advantages of the technique, and researches were conducted to evaluate this possibility, with results suggesting it could be applied but at the same time highlighting the chance of blood contamination of the environment. Consequently, a device was developed to prevent this possibility, the earlobe arterialized blood collector, which subsequently underwent a series of tests in simulated microgravity on healthy volunteers and then in clinical practice to also evaluate its potential terrestrial use. Further evaluation was conducted in the microgravity provided by an ESA parabolic flight campaign, and the 'space readiness' of the EABC was assessed through a series of electromechanical tests. In summary, research results suggest the EABC device to be space-proof, easyto-use and low-cost, enabling the collection of arterialized blood as an alternative possibility to arterial puncture/cannulation in the austere environment of space.

## **Author details**

Thais Russomano1,2

1 InnovaSpace, UK

2 Centre for Human and Applied Physiological Sciences, School of Basic and Medical Biosciences, Faculty of Life Sciences and Medicine, King's College London, UK

\*Address all correspondence to: thais@innovaspace.org

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

## **References**

[1] Lilienthal JL, Riley RL. On the determination of arterial oxygen saturations from samples of 'capillary blood. The Journal of Clinical Investigation. 1944;**23**:904-906

[2] Arterial puncture and cannulation. Available from: https://clinicalgate.com/ arterial-puncture-and-cannulation/ [Accessed: 02 January 2020]

[3] Godfrey S, Wosniak ER, Courtenay ERJ, Samuels CS. Earlobe samples for blood gas analysis at rest and during exercise. British Journal of Diseases of the Chest. 1971;**65**:68-72

[4] Koch G. The validity of PO2 measurement in capillary blood as a substitute for arterial PO2. Scandinavian Journal of Clinical and Laboratory Investigation. 1958;**21**:10-13

[5] Langlands JHM, Wallace WFM. Small blood samples from ear-lobe punctures. Lancet. 1965;**14**:315-317

[6] McIntyre J, Norman JN, Smith G. Use of capillary blood in measurement of arterial PO2. The BMJ. 1968;**3**:640-643

[7] Russomano T. The effects of 3 h of 6-degree head-down tilt with and without hypoxia and light exercise on lung function [Ph. D. Thesis]. London, UK: King's College London, University of London; 1998

[8] Lollengen H, Gebhardt U, Beier J, Hardinsky J, Borger H, Sarrasch V, et al. Central haemodynamics during zero gravity simulated by head down bed rest. Aviation, Space, and Environmental Medicine. 1984;**55**: 887-892

[9] Nixon JV, Murray RG, Bryant C, Johnson RL, Mitchell JH, Holland OB, et al. Early cardiovascular adaptation to simulated zero gravity. Journal of Applied Physiology. 1979;**46**:541-548

[10] Raine JM, Bishop JM. A-a difference in O2 tension and physiological dead space in Normal man. Journal of Applied Physiology. 1963;**18**(2):284-288

[11] Riley RL, Cournand A. Analysis of factors affecting partial pressures of oxygen and carbon dioxide in gas and blood of lungs: Theory. Journal of Applied Physiology. 1951;**4**:77-101

[12] Spiro S, Dowdeswell IRG. Arterialized earlobe blood samples for blood gas tensions. British Journal of Diseases of the Chest. 1976;**70**:263-268

[13] Russomano T, Ernsting J. The arterialized earlobe blood samples for blood gas tensions. A technique for medical emergencies in microgravity. In: 47th International Astronautical Congress, Book of Abstracts IAF/IAA – 96-G.1.12; Beijing, China; 1996. p. 23

[14] Russomano T, Doxey S, Ernsting J. Arterialized earlobe sample for arterial blood gas tensions with and without hypoxia during 6-degree headdown tilt. In: 68th Annual Scientific Meeting Program, Aerospace Medical Association, Book of Abstracts ASMA 192; Chicago, USA; 1997. p. A33

[15] Russomano T, Evetts S, Castro J, dos Santos MA, Gavillon J, de Azevedo DFG, et al. A device for sampling arterialized earlobe blood in austere environments. Aviation, Space, and Environmental Medicine. 2006;**77**:453-455

[16] Sides M, Vernikos J, Convertino V, Stepanek J, Tripp L, Draeger J, et al. The Bellagio report: Cardiovascular risks for space flight: Implications for the future of space travel. Aviation, Space, and Environmental Medicine. 2005;**76**:877-895

[17] Falcao F, Russomano T. Clinical validation of the earlobe arterialized blood collector. Aviation, Space,

**173**

*A Device for Sampling Earlobe Arterialized Blood in Space and Other Austere Environments*

*DOI: http://dx.doi.org/10.5772/intechopen.93469*

[18] Vaquer S, Masip J, Gili G, Gomà G, Oliva JC, Frechette A, et al. Earlobe arterialized capillary blood gas analysis in the intensive care unit: A pilot study. Annals of Intensive Care. 2014;**4**:11

[19] Vaquer S, Masip J, Gili G, Gomà G, Oliva JC, Frechette A, et al. Operational evaluation of the earlobe arterialized blood collector in critically ill patients. Extreme Physiology & Medicine. 2015;**4**:5

[20] Russomano T, Whittle J, Evetts J, Coats E, Vian M, Cardoso R, et al. Assessment of an earlobe arterialized blood collector in microgravity. Aviation, Space, and Environmental Medicine.

[21] Project Van Gogh - An Assessment of an Arterialised Blood Collecting Device for Use in Microgravity, Experiment Record N° 8568, ESA website, Erasmus Experiment Archive. Available from: http://eea.spaceflight. esa.int/portal/exp/?id=8568 [Accessed:

[22] NASA Systems Engineering Handbook. Available from: www.nasa. gov/sites/default/files/atoms/files/ nasa\_systems\_engineering\_handbook. pdf [Accessed: 02 January 2020]

and Environmental Medicine.

2010;**81**:1053-1054

2009;**80**:989-990

11 March 2020]

*A Device for Sampling Earlobe Arterialized Blood in Space and Other Austere Environments DOI: http://dx.doi.org/10.5772/intechopen.93469*

and Environmental Medicine. 2010;**81**:1053-1054

[18] Vaquer S, Masip J, Gili G, Gomà G, Oliva JC, Frechette A, et al. Earlobe arterialized capillary blood gas analysis in the intensive care unit: A pilot study. Annals of Intensive Care. 2014;**4**:11

[19] Vaquer S, Masip J, Gili G, Gomà G, Oliva JC, Frechette A, et al. Operational evaluation of the earlobe arterialized blood collector in critically ill patients. Extreme Physiology & Medicine. 2015;**4**:5

[20] Russomano T, Whittle J, Evetts J, Coats E, Vian M, Cardoso R, et al. Assessment of an earlobe arterialized blood collector in microgravity. Aviation, Space, and Environmental Medicine. 2009;**80**:989-990

[21] Project Van Gogh - An Assessment of an Arterialised Blood Collecting Device for Use in Microgravity, Experiment Record N° 8568, ESA website, Erasmus Experiment Archive. Available from: http://eea.spaceflight. esa.int/portal/exp/?id=8568 [Accessed: 11 March 2020]

[22] NASA Systems Engineering Handbook. Available from: www.nasa. gov/sites/default/files/atoms/files/ nasa\_systems\_engineering\_handbook. pdf [Accessed: 02 January 2020]

**172**

887-892

*Preparation of Space Experiments*

**References**

[1] Lilienthal JL, Riley RL. On the determination of arterial oxygen saturations from samples of 'capillary [10] Raine JM, Bishop JM. A-a difference in O2 tension and physiological dead space in Normal man. Journal of Applied Physiology. 1963;**18**(2):284-288

[11] Riley RL, Cournand A. Analysis of factors affecting partial pressures of oxygen and carbon dioxide in gas and blood of lungs: Theory. Journal of Applied Physiology. 1951;**4**:77-101

[12] Spiro S, Dowdeswell IRG.

Arterialized earlobe blood samples for blood gas tensions. British Journal of Diseases of the Chest. 1976;**70**:263-268

[14] Russomano T, Doxey S, Ernsting J. Arterialized earlobe sample for arterial blood gas tensions with and without hypoxia during 6-degree headdown tilt. In: 68th Annual Scientific Meeting Program, Aerospace Medical Association, Book of Abstracts ASMA 192; Chicago, USA; 1997. p. A33

[15] Russomano T, Evetts S, Castro J, dos Santos MA, Gavillon J, de Azevedo DFG, et al. A device for sampling arterialized earlobe blood in austere environments. Aviation, Space, and Environmental Medicine.

[16] Sides M, Vernikos J, Convertino V, Stepanek J, Tripp L, Draeger J, et al. The Bellagio report: Cardiovascular risks for space flight: Implications for the future of space travel. Aviation, Space, and Environmental Medicine.

[17] Falcao F, Russomano T. Clinical validation of the earlobe arterialized blood collector. Aviation, Space,

2006;**77**:453-455

2005;**76**:877-895

[13] Russomano T, Ernsting J. The arterialized earlobe blood samples for blood gas tensions. A technique for medical emergencies in microgravity. In: 47th International Astronautical Congress, Book of Abstracts IAF/IAA – 96-G.1.12; Beijing, China; 1996. p. 23

[2] Arterial puncture and cannulation. Available from: https://clinicalgate.com/ arterial-puncture-and-cannulation/

Courtenay ERJ, Samuels CS. Earlobe samples for blood gas analysis at rest and during exercise. British Journal of Diseases of the Chest. 1971;**65**:68-72

blood. The Journal of Clinical Investigation. 1944;**23**:904-906

[Accessed: 02 January 2020]

[3] Godfrey S, Wosniak ER,

[4] Koch G. The validity of PO2 measurement in capillary blood as a substitute for arterial PO2. Scandinavian Journal of Clinical and Laboratory Investigation. 1958;**21**:10-13

[5] Langlands JHM, Wallace WFM. Small blood samples from ear-lobe punctures. Lancet. 1965;**14**:315-317

[7] Russomano T. The effects of 3 h of 6-degree head-down tilt with and without hypoxia and light exercise on lung function [Ph. D. Thesis]. London, UK: King's College London, University

[8] Lollengen H, Gebhardt U, Beier J, Hardinsky J, Borger H, Sarrasch V, et al.

Central haemodynamics during zero gravity simulated by head down bed rest. Aviation, Space, and Environmental Medicine. 1984;**55**:

[9] Nixon JV, Murray RG, Bryant C, Johnson RL, Mitchell JH, Holland OB, et al. Early cardiovascular adaptation to simulated zero gravity. Journal of Applied Physiology. 1979;**46**:541-548

of London; 1998

[6] McIntyre J, Norman JN, Smith G. Use of capillary blood in measurement of arterial PO2. The BMJ. 1968;**3**:640-643

**175**

**Chapter 9**

**Abstract**

Space Station (ISS).

**1. Introduction**

cognitive, human, brain

**1.1 Project background**

GRIP: Dexterous Manipulation of

*Jean-Louis Thonnard, Laurent Opsomer, Philippe Lefèvre,* 

The aim of the GRIP experiment is to investigate how gravity impacts the kinematics and dynamics of the upper limb during dexterous manipulation of objects and how the central nervous system adapts to long-term exposure to microgravity and subsequently back to Earth gravity. Hence, we proposed to conduct a set of experiments on healthy human subjects, involving the manipulation of an instrumented object during exposure to normal and microgravity, and to study how the central nervous system adapts motor control in order to cope with the new physical environment. More particularly, the coordination between the grasping force (or grip force, GF) and the load force (LF) is studied, as well as the adaptation of the movement dynamics and kinematics and the interaction between cognitive and sensory cues that establish a reference frame for the human brain. Here we describe the background motivation, the parabolic flight tests that initiated the scientific hypotheses and the technical and scientific process that led to the implementation of the GRIP experiment currently on board the International

**Keywords:** manipulation, grip, weightlessness, gravity, force, kinematics, space,

A stable grip on handheld objects is of primary importance to lifting and moving actions particularly when such objects are used as tools. During object manipulation, predicting the consequences of one's own movements is necessary to avoid unwittingly dropping the object. Studies of the forces employed in the dexterous handling of objects have found that the grip forces are tuned to prevent accidental slips and yet are not so excessive as to crush a fragile object or to cause muscle fatigue [1]. Flanagan and Wing [2, 3] examined grip force modulation as subjects performed either point-to-point or cyclic arm movements with a handheld load. They found that variations in inertial forces caused by the subjects' own arm movements over a range of accelerations produced synchronous changes in grip forces that rose and fell with the changes in the tangential load forces on the fingers while also taking into account the friction between the fingers and the object. A tight temporal coupling between the grip force (GF) and the load force (LF) has

Objects in Weightlessness

*Vladimir Pletser and Joseph McIntyre*

**Chapter 9**
