**2. Miniaturised conventional extracorporeal circulation system**

In 1995, our project was to set up a new concept of a miniaturised conventional extracorporeal circulation (McECC) system that is both safe and versatile, which allows to reduce to the maximum console and the circuit of the ECC. A brand-new console of CPB with a holder system that permits the installation of oxygenator and HSVR at the height of the patient's shoulder, together with the five external pumps (**Figures 1** and **2**).

**2.1. Study on the ECC surface reduction**

**Figure 3.** Modified CPB "CAPS"console 1998.

**Figure 2.** Profile view.

In order to be able to confirm the hypothesis stating that the decrease of the ECC system can enhance the postoperative period on patients that have undergone a cardiac surgery, in 1997 we asked the technician of the society (Stöckert®, Müchen, Germany) to carry out some modifications on our CPB console "CAPS "of that time (**Figures 3** and **4**). This action has allowed the positioning of the systemic pump near the oxygenator, and the introduction of a set con-

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The outcome has been a drastic reduction of the length of the lines, dead space and the ECC priming volume. We gave it the name of "Compact ECC" (**Figures 3** and **4**). Regarding the" Compact ECC", we have conducted many studies and research that we have published [6, 7].

sisted of the console, oxygenator and the HSVR as close as possible to the patient.

When I realise the drawing of **Figure 1**, the CPB console of that type did not exist yet, and it was absolutely unthinkable and impossible to place the holder system on the CPB consoles which would have been launched on the market in 1995. For this reason, we put the project regarding the holder system on hold.

**Figure 1.** Top view.

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**Figure 2.** Profile view.

bleeding risks, and eventually to thrombotic, myocardial, renal or pulmonary complications and neurological dysfunctions [2–4]. During the last decade, several improvements have been made on the ECC used within cardiac surgery, especially with the arrival of many systems in the market, such as the mini-ECC and the optimised conventional ECC which are closer to the patient's physiology and having surface treatments capable of improving the hemocompatibility of ECC [5]. These new systems have allowed to reduce the aggressiveness of the ECC on the patients, allowing as a consequence a reduction of the SIRS and its negative effects on them; the final result is a decrease of morbidity and mortality of patients postoperatively.

In 1995, our project was to set up a new concept of a miniaturised conventional extracorporeal circulation (McECC) system that is both safe and versatile, which allows to reduce to the maximum console and the circuit of the ECC. A brand-new console of CPB with a holder system that permits the installation of oxygenator and HSVR at the height of the patient's shoulder,

When I realise the drawing of **Figure 1**, the CPB console of that type did not exist yet, and it was absolutely unthinkable and impossible to place the holder system on the CPB consoles which would have been launched on the market in 1995. For this reason, we put the project

**2. Miniaturised conventional extracorporeal circulation system**

together with the five external pumps (**Figures 1** and **2**).

regarding the holder system on hold.

150 Advances in Extra-corporeal Perfusion Therapies

**Figure 1.** Top view.

#### **2.1. Study on the ECC surface reduction**

In order to be able to confirm the hypothesis stating that the decrease of the ECC system can enhance the postoperative period on patients that have undergone a cardiac surgery, in 1997 we asked the technician of the society (Stöckert®, Müchen, Germany) to carry out some modifications on our CPB console "CAPS "of that time (**Figures 3** and **4**). This action has allowed the positioning of the systemic pump near the oxygenator, and the introduction of a set consisted of the console, oxygenator and the HSVR as close as possible to the patient.

The outcome has been a drastic reduction of the length of the lines, dead space and the ECC priming volume. We gave it the name of "Compact ECC" (**Figures 3** and **4**). Regarding the" Compact ECC", we have conducted many studies and research that we have published [6, 7].

**Figure 3.** Modified CPB "CAPS"console 1998.

We introduced into routine retrograde autologous priming (RAP), including arterial line, arterial filter and antegrade autologous priming of the venous line (VAP) before the start of

In interventions like CABG, during the aortic cross-clamping (closed-heart surgery), discharge of the left heart by aortic root vent is performed for the group 1–2 by gravity and for

root is equal to that applied in the venous reservoir by the VAVD system (**Figures 6** and **7**).

by vacuum-assisted venous drainage (VAVD); the depression exerted in the aortic

oxygenator Avant D903; group 3

Holder System for External Pumps Positioned Remote from the CPB Console: 23 Years' Experience

oxygenator Eos D905 and

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153

CPB. This action has allowed a precise control of the hemodilution of patients.

oxygenator Compact Flow D703; group 2

compatible HSVR with VAVD (Dideco®, Mirandola, Italy).

the group 3

**Figure 6.** Group 1

and group 2

.

**Figure 5.** Group 1

**Figure 4.** Systemic pump near the oxygenator.

In summary, this study has been conducted on three groups of patients which have undergone a coronary artery bypass grafting (CABG), from 1999 to 2004. A total of 50 patients have been analysed for the first group, from 1999 to 2001, and 25 patients in 2001 for the second group, and 25 patients for the third group from 2003 to 2004.

A significant difference among the groups concerning the patient's age, the Parsonnet score, the number of anastomoses performed, the haemoglobin before ECC, the ECC time and the systemic flow of the ECC have not been found. The systemic flow (L/min) has been measured using a flow index of 2.4 l/min/m<sup>2</sup> for each group.

All groups were operated with an open circuit McECC. We have reduced from group 1 up to group 3 the surface of air/blood contact, blood/materials contact, the dead space of the system and the priming.

After the distribution of the new systems (oxygenator and HSVR) and knowing that the surface of contact of oxygenators is the most important of the ECC circuit set, the reduction of the membrane surface area of the oxygenator adapted to the patient (e.g., body surface area, pathologies, etc.) from the group 1 up to the group 3 has been fundamental (**Figure 5**).

For each group, we have used the oxygenator, HSVR and the ECC circuit of the same company (Dideco®, Mirandola, Italy).

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**Figure 5.** Group 1 oxygenator Compact Flow D703; group 2 oxygenator Avant D903; group 3 oxygenator Eos D905 and compatible HSVR with VAVD (Dideco®, Mirandola, Italy).

We introduced into routine retrograde autologous priming (RAP), including arterial line, arterial filter and antegrade autologous priming of the venous line (VAP) before the start of CPB. This action has allowed a precise control of the hemodilution of patients.

In interventions like CABG, during the aortic cross-clamping (closed-heart surgery), discharge of the left heart by aortic root vent is performed for the group 1–2 by gravity and for the group 3 by vacuum-assisted venous drainage (VAVD); the depression exerted in the aortic root is equal to that applied in the venous reservoir by the VAVD system (**Figures 6** and **7**).

**Figure 6.** Group 1 and group 2 .

In summary, this study has been conducted on three groups of patients which have undergone a coronary artery bypass grafting (CABG), from 1999 to 2004. A total of 50 patients have been analysed for the first group, from 1999 to 2001, and 25 patients in 2001 for the second

A significant difference among the groups concerning the patient's age, the Parsonnet score, the number of anastomoses performed, the haemoglobin before ECC, the ECC time and the systemic flow of the ECC have not been found. The systemic flow (L/min) has been measured

the surface of air/blood contact, blood/materials contact, the dead space of the system

has been fundamental (**Figure 5**).

up to

for each group.

All groups were operated with an open circuit McECC. We have reduced from group 1

up to the group 3

After the distribution of the new systems (oxygenator and HSVR) and knowing that the surface of contact of oxygenators is the most important of the ECC circuit set, the reduction of the membrane surface area of the oxygenator adapted to the patient (e.g., body surface area,

For each group, we have used the oxygenator, HSVR and the ECC circuit of the same com-

group, and 25 patients for the third group from 2003 to 2004.

using a flow index of 2.4 l/min/m<sup>2</sup>

**Figure 4.** Systemic pump near the oxygenator.

152 Advances in Extra-corporeal Perfusion Therapies

pathologies, etc.) from the group 1

pany (Dideco®, Mirandola, Italy).

group 3

and the priming.

*2.1.2. Group 2*

• Flow index: 2.4 l/min/m2

• Flow index: 2.4 l/min/m2

• Level detector on the HSVR

to group 3

• Mean systemic flow of ECC 4.3 l/min

(mean 0.4 ± 0.7 vs. 0.1 ± 0.3 units/patient).

• Arterial line 3/8 in

*2.1.3. Group 3*

• Mean systemic flow of ECC 4.4 l/min

• Drainage by gravity and venous line ½ in

• Level detector on the venous reservoir

• Membrane surface area of the oxygenator 1.1 m2

• Maximum blood flow rate of the oxygenator 5 l/min

• VAVD system with the arterial/venous line 3/8 in and the HSVR

• Residual priming or hemodilution of the patient at the start of ECC = 250 ml

• Surface coating" Phosphorylcholine"(Dideco®, Mirandola, Italy) (**Figures 3**–**5**)

The result of this study shows a reduction of postoperative ventilation time from the group 1

duration of stay in intensive care unit (mean 3.6 vs. 1.9 days) and need for blood transfusion

The study also highlights that the systems used in the first two groups were very big in relation to the patients (BSA, pathologies, physiological needs), and the postoperative impact of these systems on the patients can be compared to an artificial increase in ECC time [10–17].

(mean 508 ± 325 vs. 194.6 ± 39.2 min), blood loss (mean 489.2 ± 196.4 vs236 ± 39.6 ml),

• The ECC was performed with an oxygenator Avant D903 (Dideco®, Mirandola, Italy)

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• Residual priming or hemodilution of the patient at the start of ECC = 500 ml

VAVD, system (Maquet® Cardiopulmonary GmbH, Germany) (**Figures 6** and **7**).

The ECC was performed with an oxygenator EOS D905 (Dideco®, Mirandola, Italy)

We have positioned the set of oxygenator and compatible HSVR with VAVD as close as possible to the patient's shoulder, replacing the gravity venous drainage with a ½ in vein line through a 3/8 in vein line and routinely introduced the vacuum-assisted venous drainage,

• Surface coating" Phosphorylcholine"(Dideco®, Mirandola, Italy)

• Membrane surface area of the oxygenator 1.7 m2

• Maximum blood flow rate of the oxygenator 7.5 l/min

**Figure 7.** Group 3 .

In all three groups, ECC was conducted under normothermia with warm intermittent blood cardioplegia based on potassium and magnesium. In order to verify the quality of our cardioplegia protocol, we have realised a series of studies in which one of these has been published in 2003 with the title *Comparison of the troponin i levels during coronary artery bypass graft in cardiac surgery procedures, realised with and without extracorporeal circulation* [8].

The auto transfusion system Electa (Dideco®, Mirandola, Italy) was employed for all the three groups. The volume of red blood cell concentrate re-injected for the three groups at the end of surgery did not exceed 320 ml. In order to optimise the management of the auto transfusion system, in 1998 we realised a study: *Improving the quality of red blood cells recovered with the Stat, perioperative autotransfusion system: Study of residues* [9].

#### *2.1.1. Group 1*


### *2.1.2. Group 2*


#### *2.1.3. Group 3*

In all three groups, ECC was conducted under normothermia with warm intermittent blood cardioplegia based on potassium and magnesium. In order to verify the quality of our cardioplegia protocol, we have realised a series of studies in which one of these has been published in 2003 with the title *Comparison of the troponin i levels during coronary artery bypass graft* 

The auto transfusion system Electa (Dideco®, Mirandola, Italy) was employed for all the three groups. The volume of red blood cell concentrate re-injected for the three groups at the end of surgery did not exceed 320 ml. In order to optimise the management of the auto transfusion system, in 1998 we realised a study: *Improving the quality of red blood cells recovered with the Stat,* 

• The ECC was performed with an oxygenator Compact Flow D703 (Dideco®, Mirandola,

*in cardiac surgery procedures, realised with and without extracorporeal circulation* [8].

• Residual priming or hemodilution of the patient at the start of ECC = 900 ml

*perioperative autotransfusion system: Study of residues* [9].

• Membrane surface area of the oxygenator 2 m2

• Maximum blood flow rate of the oxygenator 7 l/min

*2.1.1. Group 1*

**Figure 7.** Group 3

.

154 Advances in Extra-corporeal Perfusion Therapies

Italy)

• Flow index: 2.4 l/min/m2

• Arterial line 3/8 in

• Mean systemic flow of ECC 4.5 l/min

• Drainage by gravity and venous line ½ in

• Level detector on the venous reservoir

We have positioned the set of oxygenator and compatible HSVR with VAVD as close as possible to the patient's shoulder, replacing the gravity venous drainage with a ½ in vein line through a 3/8 in vein line and routinely introduced the vacuum-assisted venous drainage, VAVD, system (Maquet® Cardiopulmonary GmbH, Germany) (**Figures 6** and **7**).

The ECC was performed with an oxygenator EOS D905 (Dideco®, Mirandola, Italy)


The result of this study shows a reduction of postoperative ventilation time from the group 1 to group 3 (mean 508 ± 325 vs. 194.6 ± 39.2 min), blood loss (mean 489.2 ± 196.4 vs236 ± 39.6 ml), duration of stay in intensive care unit (mean 3.6 vs. 1.9 days) and need for blood transfusion (mean 0.4 ± 0.7 vs. 0.1 ± 0.3 units/patient).

The study also highlights that the systems used in the first two groups were very big in relation to the patients (BSA, pathologies, physiological needs), and the postoperative impact of these systems on the patients can be compared to an artificial increase in ECC time [10–17].
