Arterial blood gas changes during cardiac arrest and cardiopulmonary resuscitation combined with passive oxygenation/ventilation: a METI HPS study

OBJECTIVE: High-fidelity simulators can simulate physiological responses to medical interventions. The dynamics of the partial arterial pressure of oxygen (P(a)O(2)), partial arterial pressure of carbon dioxide (P(a)CO(2)), and oxygen pulse saturation (SpO(2)) during simulated cardiopulmonary resuscitation (CPR) were observed and compared with the results from the literature. METHODS: Three periods of cardiac arrest were simulated using the METI Human Patient Simulator™ (Medical Education Technologies, Inc., Sarasota, FL, USA): cardiac arrest, chest compression-only CPR, and chest compression-only CPR with continuous flow insufflation of oxygen (CFIO). RESULTS: In the first period, the observed values remained constant. In the second period, P(a)CO(2) started to rise and peaked at 63.5 mmHg. In the CFIO period, P(a)CO(2) slightly fell. P(a)O(2) and S(p)O(2) declined only in the second period, reaching their lowest values of 44 mmHg and 70%, respectively. In the CFIO period, P(a)O(2) began to rise and peaked at 614 mmHg. S(p)O(2) exceeded 94% after 2 minutes of CFIO. CONCLUSIONS: The METI Human Patient Simulator™ accurately simulated the dynamics of changes in P(a)CO(2). Use of this METI oxygenation model has some limitations because the simulated levels of P(a)O(2) and S(p)O(2) during cardiac arrest correlate poorly with the results from published studies.