Table 1 Experimental studies evaluating effects of high oxygen tensions in the cardiac arrest context
From: Hyperoxia toxicity after cardiac arrest: What is the evidence?
Study (year) | Animal (n=) | Mechanism of arrest | Arrest duration (min) | Inspired oxygen during CPR | Main outcome measure | Follow-up period after ROSC | Inspired oxygen after ROSC | Main result |
|---|---|---|---|---|---|---|---|---|
Zwemer (1994) | Dogs (27) | Electrical | 9 | 21 versus 100 % | Neurological (score) | 24 h | 21 versus 100 % during 1 h then room air during 24 h | Worse neurological outcome after hyperoxia |
Marsala (1992) | Dogs (13) | Intracardial KCl bolus | 15 | 21 versus 100 % | Neurological (histological) | 1 h | 21 versus 100 % | Increased neuron vulnerability after hyperoxia |
Zwemer (1995) | Dogs (17) | Electrical | 9 | 8.5 versus 12 versus 21 % during 15 min | Mortality and neurological (score) | 24 h | Room air 15 min after CPR | Worse neurological outcome and increased mortality after hypoxia |
Liu (1998) | Dogs (20) | Electrical | 10 | 21 versus 100 % | Neurological (score) and oxidative stress (lipid peroxidation) | 24 h | 21–30 versus 100 % | Worse neurological outcome and increased oxidative stress after hyperoxia |
Lipinski (1998) | Rats (22) | Asphyxia | 5–8 | 21 versus 100 % | Neurological (score) | 24, 48, 72 h | 21 versus 100 % during 1 h then room air | No differences |
Rosenthal (2003) | Dogs (9) | Electrical | 10 | Hyperbaric oxygenation versus 21 % | Neurological (score and histological) | 24 h | Hyperbaric oxygenation versus 21 % | Hyperbaric oxygenation improved neurological outcome |
Vereczki (2006) | Dogs (12) | Electrical | 10 | 21 versus 100 % | Neurological (score) and oxidative stress (pyruvate dehydrogenase) | 24 h | 100 % for 1 h versus 21 % then PaO2 [80–100] in both groups | Increased oxidative stress and delayed neuronal death |
Balan (2006) | Dogs (17) | Electrical | 10 | 100 % | Neurological (score and histological) | 24 h | 100 % for 1 h versus 21–30 % with titration | Oxymetry-guided reoxygenation improved neurological score and decreased neuronal death |
Richards (2006) | Dogs (16) | Electrical | 10 | 21 versus 100 % | Antioxidative enzyme (pyruvate dehydrogenase) | 2 h | 100 % for 1 h versus 21–30 % with titration | Hyperoxia impairs oxidative stress metabolism |
Richards (2007) | Dogs (13) | Electrical | 10 | 21 versus 100 % | Oxidative stress (glutamate) | 2 h | 100 % for 1 h versus 21–30 % with titration | Hyperoxia impairs oxidative metabolism |
Yeh (2009) | Rats (23) | Intravenous KCl bolus | 6 | 0 versus 21 versus 100 % | Neurological (score) | 1 h | 0 versus 21 versus 100 % during 2 min then all animals with 100 % | CPR ventilation without oxygen worsen neurological score |
Bruchen (2010) | Pig (15) | Electrical | 8 | 100 % | Neurological (score and histological) | 5 days | 100 % during 10 min versus 60 min | Prolonged hyperoxia aggravated neurological outcome |
Angelos (2011) | Rats (?) | Intravenous KCl bolus | 6.5 | 21 % | Heart mitochondrial respiratory function | 1 h | 40 versus 100 % for 60 min | Hyperoxia impaired heart mitochondrial function |