Early selective trans-nasal cooling during CPR improves success of resuscitation in a porcine model of prolonged pulseless electrical activity cardiac arrest

AIM OF STUDY: In the present study, we investigated trans-nasal cooling in settings of pulseless electrical activity (PEA). We hypothesized that early trans-nasal cooling during CPR improves outcomes when cardiac arrest is associated with PEA. METHODS: Ventricular fibrillation (VF) was electrically induced in 16 domestic male pigs weighing 40±3 kg. After 14 min of untreated VF, PEA was induced following delivery of one or more electrical shocks. One min after onset of PEA, CPR was started, including chest compression and ventilation. Each animal received 5 min of CPR prior to defibrillation attempt. CPR and resuscitation efforts were discontinued at 15 min unless return to spontaneous circulation was achieved. In 8 animals, selective trans-nasal cooling was begun coincident with start of CPR and 8 randomized controls were identically treated except for trans-nasal cooling. Mean aortic pressure was continuously measured together with aortic and right atrial pressure and nasal, body and right jugular vein temperatures. Coronary perfusion pressure (CPP) was computed from measured data. RESULTS: Six of eight animals were resuscitated after early trans-nasal cooling, while only one untreated control was resuscitated (p=0.012). Nasal, body and jugular vein temperatures decreased after cooling. At PC (precordial compression) 5 min, the cooled group recorded a higher CPP (25±5 mmHg) than the non-cooled group (15±4 mmHg, p=0.001). CONCLUSION: When selective trans-nasal cooling was initiated during CPR in the animal model of prolonged cardiac arrest with PEA, CPP was higher and the likelihood of return of spontaneous circulation was improved.