The PAC (Post-operative Airway Compromise) score – First steps to Develop a Post-Surgery Tool for the Assessment of Upper Airway-related Complications following Anterior Cervical Spine Surgery

Background Acute upper airway compromise is a rare but catastrophic complication after anterior cervical discectomy and fusion (ACDF). This study aims to develop a score to identify patients at risk for acute postoperative airway compromise (PAC). Methods Potential risk factors for acute PAC were selected by a modified Delphi process. Ten patients with acute PAC were identified out of 1,466 patients who underwent elective ACDF between July 2014 - May 2019. A comparison group was created by a randomized selection process (non-PAC group). Associated factors with PAC and a p-value <.10 were entered into a logistic regression model and coefficients contributed each risk factor's overall score. Calibration of the model was evaluated by Hosmer-Lemeshow (H-L) goodness-of-fit test. Quantitative discrimination was calculated and the final model was internally validated with bootstrap sampling. Results We identified 18 potential risk factors from our Delphi process, of which 6 factors demonstrated a significant association with airway compromise: age >65 years, current smoking status, ASA >2, history of a bleeding disorder, surgery of upper subaxial cervical spine (>C4), and duration of surgery >179 min. The final prediction model included five predictors with very strong performance characteristics. These five factors formed the PAC-Score (PACS) which had a range from 0 to 100. A score of 20 yielded the greatest balance of sensitivity (80%) and specificity (88%). Conclusions The acute Postoperative Airway Compromise Score (PACS) demonstrates strong performance characteristics. The PAC score may help identify patients at risk for upper airway compromise caused by surgical site abnormalities.