Risk Factors for Post-Tonsillectomy Hemorrhage: A 10-Year Retrospective Cohort Study at a Tertiary Military Hospital in Thailand.

Objective: Tonsillectomy is one of the most frequently performed surgical procedures worldwide, and several patient-and procedure-related factors have been associated with post-tonsillectomy hemorrhage (PTH). Severe hemorrhage may require reoperation under general anesthesia to achieve hemostasis. The aim of this retrospective cohort study was to identify pre-, intra-, and postoperative factors associated with PTH.

Methods: Records of 549 patients who underwent tonsillectomy at a tertiary military hospital in Thailand between 2010 and 2020 were reviewed, with PTH ascertained by detailed manual chart review.

Results: The mean age was 26.89±15.69 years. PTH occurred in 56 patients (10.2%), most commonly on postoperative day 6. Multivariate logistic regression identified the following independent risk factors: male sex [p=0.039; adjusted odds ratio (aOR) 2.11, 95% confidence interval (CI) 1.04-4.30], age<19 years (p=0.016; aOR 7.96, 95% CI 1.46-43.27), age 19-45 years (p=0.024; aOR 5.74, 95% CI 1.26-26.11), surgeon experience <15 years (p=0.023; aOR 2.85, 95% CI 1.16-7.01), elevated mean arterial pressure (MAP) (p=0.002; aOR 1.04 per mmHg, 95% CI 1.02-1.07), intravenous (IV) antibiotic prescription (p=0.036; aOR 2.03, 95% CI 1.05-3.92), and a day-1 pain score >5 (p=0.037; aOR 2.25, 95% CI 1.05-4.81). As the >45-year reference group had few events, the age odds ratios were imprecise; a Firth-penalized pediatric estimate was 6.33 (95% CI 1.52-37.37), and a pooled age <45 versus ≥45 contrast gave aOR 5.07 (95% CI 1.56-26.00).

Conclusion: Male sex, age under 45 years, and surgeon experience less than 15 years were the principal independent predictors of PTH; elevated postoperative MAP, a day-1 pain score above 5, and IV antibiotic prescription further characterized higher-risk patients.