Hemodynamic directed CPR improves cerebral perfusion pressure and brain tissue oxygenation

Abstract

Aim: Advances in cardiopulmonary resuscitation (CPR) have focused on the generation and maintenance of adequate myocardial blood flow to optimize the return of spontaneous circulation and survival. Much of the morbidity associated with cardiac arrest survivors can be attributed to global brain hypoxic ischemic injury. The objective of this study was to compare cerebral physiological variables using a hemodynamic directed resuscitation strategy versus an absolute depth-guided approach in a porcine model of ventricular fibrillation (VF) cardiac arrest.

Methods: Intracranial pressure and brain tissue oxygen tension probes were placed in the frontal cortex prior to induction of VF in 21 female 3-month-old swine. After 7 min of VF, animals were randomized to receive one of three resuscitation strategies: (1) hemodynamic directed care (CPP-20): chest compressions (CCs) with depth titrated to a target systolic blood pressure of 100 mmHg and titration of vasopressors to maintain coronary perfusion pressure (CPP)>20 mmHg; (2) depth 33 mm (D33): target CC depth of 33 mm with standard American Heart Association (AHA) epinephrine dosing; or (3) depth 51 mm (D51): target CC depth of 51 mm with standard AHA epinephrine dosing.

Results: Cerebral perfusion pressures (CerePP) were significantly higher in the CPP-20 group compared to both D33 (p<0.01) and D51 (p=0.046), and higher in survivors compared to non-survivors irrespective of treatment group (p<0.01). Brain tissue oxygen tension was also higher in the CPP-20 group compared to both D33 (p<0.01) and D51 (p=0.013), and higher in survivors compared to non-survivors irrespective of treatment group (p<0.01). Subjects with a CPP>20 mmHg were 2.7 times more likely to have a CerePP>30 mmHg (p<0.001).

Conclusions: Hemodynamic directed resuscitation strategy targeting coronary perfusion pressure>20 mmHg following VF arrest was associated with higher cerebral perfusion pressures and brain tissue oxygen tensions during CPR.

Keywords: Brain tissue oxygen tension; Cardiopulmonary resuscitation; Cerebral perfusion pressure; Coronary perfusion pressure; Intracranial pressure; Ventricular fibrillation.

Figure 1

A) Mean cerebral perfusion pressure (CerePP) during each minute of cardiopulmonary resuscitation (CPR) across treatment groups. B) Mean coronary perfusion pressure (CPP) during each minute of cardiopulmonary resuscitation (CPR) across treatment groups. Error bars represent SEM. Depth 33 and Depth 51 refer to depth-guided CPR at 33 mm and 51 mm, respectively. CPP-20 = CPR directed to attain coronary perfusion pressure > 20 mm Hg.

Figure 2

A) Mean cerebral perfusion pressure (CerePP) during each minute of cardiopulmonary resuscitation (CPR) between survivors and non-survivors. B) Mean coronary perfusion pressure (CPP) during each minute of cardiopulmonary resuscitation (CPR) between survivors and non-survivors. Error bars represent SEM.

Figure 3

Mean brain tissue oxygenation as a percentage of baseline during each minute of cardiopulmonary resuscitation (CPR) across treatment groups. Error bars represent SEM. Depth 33 and Depth 51 refer to depth-guided CPR at 33 mm and 51 mm, respectively. CPP-20 = CPR directed to attain coronary perfusion pressure > 20 mm Hg.

Figure 4

Mean brain tissue oxygenation as a percentage of baseline during each minute of cardiopulmonary resuscitation (CPR) between survivors and non-survivors. Error bars represent SEM.

Figure 5

Scatterplot of coronary perfusion pressure (CPP) and cerebral perfusion pressure (CerePP) residuals calculated utilizing a linear regression model for each variable adjusted for time; r = 0.76, P<0.001. Smoothing spline (bold line) demonstrates strong positive correlation between CPP and CerePP.