Association between intraoperative hypotension and postoperative nausea and vomiting: a retrospective analysis of 247 thyroidectomy cases

BACKGROUND: Postoperative nausea and vomiting (PONV) are major complications after general anesthesia. Although various pathways are involved in triggering PONV, hypotension plays an important role. We hypothesized that intraoperative hypotension during general anesthesia might be responsible for the incidence of PONV. METHODS: We retrospectively investigated patients who underwent thyroidectomy. The initial blood pressure measured before induction of anesthesia was used as the baseline value. The systolic blood pressure measured during the operation from the start to the end of anesthesia was extracted from anesthetic records. The time integral value when the measured systolic blood pressure fell below the baseline value was calculated as area under the curve (AUC) of s100%. RESULTS: There were 247 eligible cases. Eighty-eight patients (35.6%) had PONV. There was no difference in patient background between the patients with or without PONV. Univariate analysis showed that the total intravenous anesthesia (TIVA) (p = 0.02), smoking history (p = 0.02), and AUC-s100% (p = 0.006) were significantly associated with PONV. Multiple logistic regression analysis revealed that TIVA (OR: 0.54, 95% CI: 0.29...0.99), smoking history (OR: 0.60, 95% CI: 0.37...0.96), and AUC-s100% (OR: 1.006, 95% CI: 1.0...1.01) were significantly associated with PONV. CONCLUSION: Intraoperative hypotension evaluated by AUC-s100% was related to PONV in thyroidectomy.