Factors associated with 30-day mortality after perioperative cardiac arrest in adults undergoing non-cardiac surgery: a seven-year observational study from Siriraj Hospital.

Background: Perioperative cardiac arrest (PCA) in non-cardiac surgery patients is a rare but potentially catastrophic event with high mortality. Several studies highlighted factors contributing to PCA within the surgical population, but information on its outcomes remains limited. This study sought to identify independent factors associated with 30-day mortality after PCA in adults undergoing non-cardiac surgery. Methods: A retrospective cohort study was performed to identify these factors, PCA incidence, and incidence of 30-day mortality in non-cardiac surgery patients between 2015 to 2021 at Siriraj Hospital. Data collection entailed patient characteristics, surgical and anesthetic procedures, cardiac arrest details, and outcomes. Univariable and multivariable logistic regression analyses were performed to identify risk factors. Results: One hundred and five PCA cases from the Siriraj Hospital database were assessed from 259,372 anesthesia cases. Independent risk factors significantly associated with 30-day mortality included: preoperative vasopressor use [adjusted relative risk (aRR) 1.90, 95% CI: 1.08-3.32, P=0.025], cardiopulmonary resuscitation (CPR) outside a monitored setting (aRR 1.85, 95% CI: 1.08-3.17, P=0.025), and administering CPR for >15 minutes (aRR 1.97, 95% CI: 1.08-3.57, P=0.027). Univariable analysis found that a physical status classification of four to five by the American Society of Anesthesiologists and use of emergency procedures were also associated with 30-day mortality after PCA. Subgroup analysis revealed that in the emergency group, CPR durations >15 minutes were significantly associated with increased 30-day mortality (aRR 2.05, 95% CI: 1.29-3.28, P=0.003). Overall incidences of PCA and 30-day mortality after PCA were 4.31 per 10,000 and 2.00 per 10,000 cases, respectively. The one-year mortality rate for patients who experienced PCA was 67.6%. The most common cause was hypovolemia (18.1%), followed by acute coronary syndrome (13.3%). Conclusions: Preoperative vasopressor use was a pre-arrest contributing factor to 30-day mortality after PCA. Performing CPR outside a monitored setting and administering CPR for >15 minutes were two intra-arrest factors strongly linked to decreased survivability. While these factors are difficult to modify, vigilant monitoring of high-risk patients before PCA occurs and early detection of PCA, along with prompt and aggressive intervention, may improve patient outcomes.