Associations between body size and outcomes of adult in-hospital cardiac arrest: A retrospective cohort study

Aim: Animal studies have demonstrated that hemodynamic-directed cardiopulmonary resuscitation (CPR) improves outcomes following cardiac arrest compared with the "one-size-fits-all" algorithm. We investigated whether body size of patients is correlated with outcomes of in-hospital cardiac arrest (IHCA). Methods: A retrospective study in a single centre was conducted. Adult patients experiencing IHCA between 2006 and 2015 were screened. Body mass index (BMI) was calculated using body weight and height measured at hospital admission. Thoracic anteroposterior diameter (APD) was measured by analysing computed tomography images. Multivariate logistic regression analysis was used to study the associations between independent variables and outcomes. Generalised additive models were used to identify cut-off points for continuous variables. Results: A total of 766 patients were included, and 60.4% were male. Their mean age was 62.8 years. Mean BMI was 22.9 kg/m(2), and the mean thoracic APD was 21.4 cm. BMI > 23.2 kg/m(2) was inversely associated with a favourable neurological outcome (odds ratio [OR]: 0.30, 95% confidence interval [CI]: 0.13-0.68; p-value=0.004), while thoracic APD was not. When the interaction term was analysed, BMI > 23.2 (kg/m(2)) xthoracic APD > 18.5 (cm) was inversely associated with both a favourable neurological outcome (OR: 0.33, 95% CI: 0.16-0.69; p-value=0.003) and survival to hospital discharge (OR: 0.46, 95% CI: 0.26-0.81; p-value=0.007). Conclusion: Higher BMI and thoracic APD was correlated with worse outcomes following IHCA. For those patients, it might be better to perform CPR under guidance of physiological parameters rather than a "one-size-fitsall" resuscitation algorithm to improve outcomes.