Editors' note: EPR is an important concept to know for intensivists.
Read basics of EPR here
Objective: The induction of deep cerebral hypothermia via ice-cold saline aortic flush during prolonged ventricular fibrillation cardiac arrest, followed by hypothermic stasis and delayed resuscitation (emergency preservation and resuscitation), improved neurologic outcome after cardiac arrest in pigs, as compared to conventional resuscitation. We hypothesized that emergency preservation and resuscitation with chest compressions would further improve outcome in the same model.
Method: Twenty-four female, large, white breed pigs (27–37 kg). 15 minutes of ventricular fibrillation cardiac arrest were followed by
- 20 mins of resuscitation with chest compressions (control, n = 8),
- deep cerebral hypothermia via 200 mL/kg 4°C saline aortic flush and hypothermic stasis (emergency preservation and resuscitation, n = 8), and
- emergency preservation and resuscitation combined with chest compressions (emergency preservation and resuscitation plus chest compressions, n = 8).
At 35 mins after cardiac arrest, cardiopulmonary bypass was initiated, followed by defibrillation. Mild hypothermia was continued for 20 hrs. Pigs were evaluated after 9 days using a neurologic deficit (neurologic deficit score: 100% = brain dead; 0%–10% = normal) and an overall performance category score (overall performance category score: 1 = normal; 2 = slightly handicapped; 3 = severely handicapped; 4 = comatose; 5 = dead/brain dead.
Results: Brain temperature decreased from 38.5°C to 15.3°C ± 3.3°C in the emergency preservation and resuscitation group, and to 11.3°C ± 1.2°C in the emergency preservation and resuscitation plus chest compressions group.
- In the control group, restoration of spontaneous circulation was achieved in four out of eight pigs, and one survived to 9 days.
- In the emergency preservation and resuscitation group, restoration of spontaneous circulation was achieved in seven out of eight pigs and five survived;
- in the emergency preservation and resuscitation plus chest compressions group, all had restoration of spontaneous circulation and seven survived (restoration of spontaneous circulation, p = .08).
- Neurologic outcome for (median and interquartile range) the control group included overall performance category score of 3, neurologic deficit score of 45%;
- For the emergency preservation and resuscitation group, overall performance category score was 3 (2–5) and neurologic deficit score was 45% (36; 50) and
- in the emergency preservation and resuscitation plus chest compressions group, overall performance category score was 2 (1–3) and neurologic deficit score was 13% (5; 21)
Conclusions: Emergency preservation and resuscitation by deep cerebral hypothermia combined with chest compressions during prolonged cardiac arrest in pigs are feasible and improve neurologic outcome.
