LUNG COMPLIANCE FOLLOWING CARDIAC-ARREST

Objective: To determine lung compliance in patients who had out-of-hos pital cardiac arrests. Methods: A prospective, observational study of patients suffering nontraumatic cardiopulmonary arrest and requiring C PR at one university hospital ED. Following termination of resuscitati on efforts, lung compliance was measured, Measurements were made while inflating the lung from 250 mt to 2,000 mt (in 250-mL increments) usi ng a calibrated supersyringe. Airway flow and pressure were measured a t the endotracheal tube with a pneumotachograph and a pressure transdu cer. Flow and pressure signals were recorded by a respiratory monitor and used to construct pressure-volume curves for calculation of lung c ompliance. Results: The 25 cardiac arrest patients (17 men, eight wome n) had a mean (+/-SD) age of 65 +/- 7 years. Mean lung compliance was 0.051 +/- 0.011 L/cm H2O. Lung compliance was smaller at low lung volu mes, suggesting the presence of alveolar collapse. Compliance values f rom 500 mt to 1,500 mt were similar. Compliance also diminished with i ncreasing duration of CPR. Conclusions: One previous publication sugge sted that lung compliance following resuscitation is 0.022 L/cm H2O. T he results of this study, using the accepted standard measurements of static lung compliance, suggest that true compliance is twice this val ue. This finding has important ramifications for future research on ve ntilation during resuscitation and current ventilation standards.