Objective: To evaluate whether Surgical Apgar Scores measure the relationship between intraoperative care and surgical outcomes.
Summary background data: With preoperative risk-adjustment now well-developed, the role of intraoperative performance in surgical outcomes may be considered. We previously derived and validated a 10-point Surgical Apgar Score--based on intraoperative blood loss, heart rate, and blood pressure--that effectively predicts major postoperative complications within 30 days of general and vascular surgery. This study evaluates whether the predictive value of this score comes solely from patients' preoperative risk or also measures care in the operating room.
Methods: Among a systematic sample of 4119 general and vascular surgery patients at a major academic hospital, we constructed a detailed risk-prediction model including 27 patient-comorbidity and procedure-complexity variables, and computed patients' propensity to suffer a major postoperative complication. We evaluated the prognostic value of patients' Surgical Apgar Scores before and after adjustment for this preoperative risk.
Results: After risk-adjustment, the Surgical Apgar Score remained strongly correlated with postoperative outcomes (P < 0.0001). Odds of major complications among average-scoring patients (scores 7-8) were equivalent to preoperative predictions (likelihood ratio (LR) 1.05, 95% CI 0.78-1.41), significantly decreased for those who achieved the best scores of 9-10 (LR 0.52, 95% CI 0.35-0.78), and were significantly poorer for those with low scores--LRs 1.60 (1.12-2.28) for scores 5-6, and 2.80 (1.50-5.21) for scores 0-4.
Conclusions: Even after accounting for fixed preoperative risk--due to patients' acute condition, comorbidities and/or operative complexity--the Surgical Apgar Score appears to detect differences in intraoperative management that reduce odds of major complications by half or increase them by nearly 3-fold.