Do physiological changes in pregnancy change defibrillation energy requirements?

Abstract

Resuscitation during pregnancy is uncommon, with approximately 70 deaths occurring during pregancy in the UK per annum. Physiological changes during pregnancy may affect transthoracic impedance (TTI), which determines transmyocardial current. Increased blood volume, cardiomegaly, haemodilution, changes in lung volume and changes in thoracic volume may alter impedance in ways that are difficult to predict. We measured TTI at term and after delivery once physiological changes had resolved. Mean (SD) TTI was 91.3 (15.8) Ω at term and 91.6 (11.8) Ω 6-8 weeks after delivery; the difference was not statistically significant. We conclude that current energy requirements for adult defibrillation are appropriate for use during pregnancy.