**8.1 End-tidal carbon dioxide monitoring**

ETCO2 is an indirect measure of the cardiac output and pulmonary blood flow. The right side of the heart receives CO2 containing venous blood which is pumped to lungs for exhalation. Over 35 clinical studies have been conducted to explore the association and prognostication of end-tidal carbon dioxide with ROSC and survival of the patients [76, 77]. Low values of ETCO2 reflect low cardiac output state during chest compressions. Clinical significance of end-tidal carbon dioxide during CPR is varied with wide applications. It is well known that a low ETCO2 values (<10 mm Hg) have been associated with very high mortality [78]. It has been observed that a higher ETCO2 value during CPR has been associated with higher chances of ROSC. The American Heart Association also recommends ETCO2 level of greater than 20 mm Hg as an indicator of good chest compressions. There are some limitations of ETCO2 monitoring during CPR. There can be a significantly higher level of ETCO2 in asphyxia related cardiac arrest during the initial few minutes of CPR [79]. Similarly, epinephrine administration can reduce ETCO2 levels due to pulmonary vasoconstriction. Despite these limitations, ETCO2 remains one of the most important physiological parameters guiding resuscitation due to its availability, simplicity, and non-invasive technique.

## **8.2 Cerebral oximetry**

Neurological injuries are common during cardiac arrest. Maintaining cerebral perfusion during CPR is crucial for survival and good neurological outcome. Cerebral oximetry is a newer technique to measure regional cerebral oxygenation using near-infrared spectroscopy (NIRS) devices. The device emits continuous near-infrared light from a source probe and received by a detector probe on the forehead. The light penetrates the cranial cavity (few centimeters) depending on the water and lipid content [80]. Change in light intensities due to differential absorption by oxygenated and deoxygenated blood in the cranial cavity detects rSO2. There is no RCT comparing the use of commercially available NIRS devices during CPR. A multicenter observational prospective study with cerebral oximetry during cardiac arrest in an adult cohort population showed a lower percentage of IHCA patients with ROSC who had lower values of rSO2 [81]. There are certain limitations to this technological advancement of the non-invasive method of measuring regional cerebral oxygenation. There are no defined values of rSO2 derived from RCTs and meta-analysis during CPR. There is a logistics issue in placing of NIRS monitors during CPR with commercially available monitors. Prospective studies are required to validate these devices and define values of rSO2 for target approach during CPR.

#### **8.3 Focused cardiac ultrasound**

Use of point of care cardiac ultrasound during a cardiac arrest has been implemented to find the cause of cardiac arrest (5Hs and 5Ts) rather than guiding the resuscitations. However, some imaging studies have revealed the intrathoracic

**11**

*Cardiopulmonary Resuscitation: Recent Advances DOI: http://dx.doi.org/10.5772/intechopen.91866*

programs can be used to mitigate this problem.

**9. Cardiac arrest in special circumstances**

the possible reversible causes of traumatic cardiac arrest [93].

**9.1 Traumatic cardiac arrest**

thorax, and cardiac tamponade.

tation (crystalloids) [99].

*9.1.2 Tension pneumothorax*

*9.1.1 Hypovolemia and rapid fluid resuscitation*

structures beneath the described rescuer's hand position (lower half of sternum) during chest compression may be aorta or left ventricle outflow tract (LVOT) which would obstruct the blood outflow [82, 83]. A prospective study by Hwang et al. using transesophageal cardiac ultrasound identified compressions of aorta and LVOT in all the cases of chest compressions during CPR with variable degrees. The authors suggested that LV stroke volume increased by improving the precisions of compressions proximal to left ventricle guided by cardiac ultrasound [84]. However, no RCT has been done to explore the use of cardiac ultrasound during CPR. Moreover, there may be a risk of the potential harm of distracting the rescuers from high-quality CPR while focusing on cardiac ultrasound [85]. Simulation-based

The traumatic arrest is one of the etiologies of cardiac arrest with a very poor outcome [86–92]. To improve its outcome, there is a need to draw our attention to

Recent data has clarified that traumatic cardiac arrest patients have no worse outcome than that of the medical causes of cardiac arrest [94]. Some of the reversible causes of cardiac arrest in traumatic patients are hypovolemia, tension pneumo-

In-depth analysis of traumatic cardiac arrest patients has demonstrated that the majority of the survivable traumatic cardiac arrest patients have pulseless electrical activity (PEA) [95]. This implies that the heart is beating, but the peripheral pulse is not palpable. It is often seen that this is a low output state rather than a true cardiac arrest. This is supported by the fact that such patients often have multiple wounds and suffer significant blood loss. Chest compressions are more effective in euvolemic patients as compared to suspected hypovolemic patients of traumatic cardiac arrest, rather they can worsen coronary perfusion [96]. Considering the etiology, the treatment algorithm must also be modified in these cases. Treatment must involve external compression to stop further loss, gaining access to wide-bore cannula, and initiate rapid transfusion of blood and blood products along with the attempts of CPR. In contrast to the traditional teaching, blood and blood products are preferred over the crystalloid transfusion [97, 98]. Although supportive evidence has demonstrated improved survival in patients receiving more fluid resusci-

Tension pneumothorax may be suspected when there is decreased air entry even after checking the position of the endotracheal tube. It is one of the reversible causes of cardiac arrest, it is stated that chest compression should not delay the treatment of the reversible cause. It can either be achieved by immediate needle decompression or thoracotomy. In the case of positive pressure ventilation, thoracostomy is a preferred technique as it is more effective than needle decompression and less time-consuming that chest tube insertion [86]. Whereas, in the case of needle decompression, there can be technical difficulties like kinking, dislodgment, *Cardiopulmonary Resuscitation: Recent Advances DOI: http://dx.doi.org/10.5772/intechopen.91866*

*Sudden Cardiac Death*

situations. This mandates the development of newer strategies to target physiological parameters to guide resuscitation. Recent literature has reviewed the applications of various basic and advance physiological monitoring to improve precision during CPR and improve survival of the patients. Various strategies of monitoring include ETCO2 monitoring, coronary perfusion pressure monitoring, cardiac

ETCO2 is an indirect measure of the cardiac output and pulmonary blood flow. The right side of the heart receives CO2 containing venous blood which is pumped to lungs for exhalation. Over 35 clinical studies have been conducted to explore the association and prognostication of end-tidal carbon dioxide with ROSC and survival of the patients [76, 77]. Low values of ETCO2 reflect low cardiac output state during chest compressions. Clinical significance of end-tidal carbon dioxide during CPR is varied with wide applications. It is well known that a low ETCO2 values (<10 mm Hg) have been associated with very high mortality [78]. It has been observed that a higher ETCO2 value during CPR has been associated with higher chances of ROSC. The American Heart Association also recommends ETCO2 level of greater than 20 mm Hg as an indicator of good chest compressions. There are some limitations of ETCO2 monitoring during CPR. There can be a significantly higher level of ETCO2 in asphyxia related cardiac arrest during the initial few minutes of CPR [79]. Similarly, epinephrine administration can reduce ETCO2 levels due to pulmonary vasoconstriction. Despite these limitations, ETCO2 remains one of the most important physiological parameters guiding resuscitation due to its

Neurological injuries are common during cardiac arrest. Maintaining cerebral

Use of point of care cardiac ultrasound during a cardiac arrest has been implemented to find the cause of cardiac arrest (5Hs and 5Ts) rather than guiding the resuscitations. However, some imaging studies have revealed the intrathoracic

perfusion during CPR is crucial for survival and good neurological outcome. Cerebral oximetry is a newer technique to measure regional cerebral oxygenation using near-infrared spectroscopy (NIRS) devices. The device emits continuous near-infrared light from a source probe and received by a detector probe on the forehead. The light penetrates the cranial cavity (few centimeters) depending on the water and lipid content [80]. Change in light intensities due to differential absorption by oxygenated and deoxygenated blood in the cranial cavity detects rSO2. There is no RCT comparing the use of commercially available NIRS devices during CPR. A multicenter observational prospective study with cerebral oximetry during cardiac arrest in an adult cohort population showed a lower percentage of IHCA patients with ROSC who had lower values of rSO2 [81]. There are certain limitations to this technological advancement of the non-invasive method of measuring regional cerebral oxygenation. There are no defined values of rSO2 derived from RCTs and meta-analysis during CPR. There is a logistics issue in placing of NIRS monitors during CPR with commercially available monitors. Prospective studies are required to validate these devices and define values of rSO2 for target

ultrasound and regional cerebral oxygen monitoring.

availability, simplicity, and non-invasive technique.

**8.2 Cerebral oximetry**

approach during CPR.

**8.3 Focused cardiac ultrasound**

**8.1 End-tidal carbon dioxide monitoring**

**10**

structures beneath the described rescuer's hand position (lower half of sternum) during chest compression may be aorta or left ventricle outflow tract (LVOT) which would obstruct the blood outflow [82, 83]. A prospective study by Hwang et al. using transesophageal cardiac ultrasound identified compressions of aorta and LVOT in all the cases of chest compressions during CPR with variable degrees. The authors suggested that LV stroke volume increased by improving the precisions of compressions proximal to left ventricle guided by cardiac ultrasound [84]. However, no RCT has been done to explore the use of cardiac ultrasound during CPR. Moreover, there may be a risk of the potential harm of distracting the rescuers from high-quality CPR while focusing on cardiac ultrasound [85]. Simulation-based programs can be used to mitigate this problem.
