The CAPS Study: incidence, management and outcomes of cardiac arrest in pregnancy in the UK: a prospective, descriptive study

Objective To describe the incidence, risks, management and outcomes of cardiac arrest in pregnancy in the UK population, with specific focus on the use of perimortem caesarean section (PMCS). Design A prospective, descriptive study using the UK Obstetric Surveillance System (UKOSS). Setting All UK hospitals with maternity units. Population All women who received basic life support in pregnancy in the UK between 1 July 2011 and 30 June 2014 (n = 66). Methods Prospective case identification through UKOSS monthly mailing. Main outcome measures Cardiac arrest in pregnancy, PMCS, maternal death. Results There were 66 cardiac arrests in pregnancy, resulting in an incidence of 2.78 per 100 000 maternities (1: 36 000; 95% CI 2.23.6). In all, 28 women died (case fatality rate 42%); 16 women arrested solely as a consequence of obstetric anaesthesia, 12 of whom were obese. Basic and advanced life support were rapidly delivered. Those who died were more likely to have collapsed at home. Perimortem caesarean section was performed in 49 women, 11 in the emergency department. The time from collapse to PMCS was significantly shorter in women who survived (median interval 3 versus 12 minutes, P = 0.001). Forty-six of 58 babies were born alive; 32 babies to surviving mothers and 14 to women who died. Conclusion Cardiac arrest is rare in the pregnant UK population, however, nearly a quarter of cases are precipitated by obstetric anaesthesia, suggesting an opportunity to reduce the incidence further. Maternal survival rates of 58% were achieved with timely resuscitation, including PMCS, delay in which was associated with maternal death. Inpatient arrests were associated with higher survival rates than arrests that occurred outside the hospital setting.