Increase in Intraoperative Urine Output During Tympanoplasty: A Retrospective Cohort Study

We sometimes encounter cases with unexpected increase in intraoperative urine output during tympanoplasty. However, no previous study has evaluated whether intraoperative urine output during tympanoplasty is higher than that during other surgeries. Thus, this study aimed to evaluate the association between tympanoplasty and intraoperative urine output.

This single-center retrospective cohort study was conducted by assessing the records of patients who underwent tympanoplasty, sinus surgery, or thyroidectomy under general anesthesia between April 2013 and March 2017. We defined intraoperative polyuria as a urine output rate of ≥ 2.5 mL/kg/h. The factors associated with high urine output were investigated using multivariable analysis. The influence of tympanoplasty on intraoperative urine output was evaluated after propensity score matching that excluded confounding factors, except the surgical procedure.

Intraoperative polyuria occurred in 48 of 173 patients (27.7%) who underwent tympanoplasty. Multivariable analysis revealed that tympanoplasty (p = 0.001), operative time of ≥ 3 h (p = 0.010), and fluid infusion volume of ≥ 5 mL/kg/h (p = 0.029) were risk factors for polyuria. Among the study patients, 100 who underwent tympanoplasty (tympanoplasty group) and 100 who underwent sinus surgery or thyroidectomy (control group) were matched by propensity score analysis. The intraoperative urine output rate was significantly higher in the tympanoplasty group than in the control group (1.2 [0.51-2.20] mL/kg/h vs. 0.70 [0.32-1.60] mL/kg/h, p = 0.010).

Our findings indicate that intraoperative urine output is higher during tympanoplasty than that during other otologic surgeries.