Incidence and Risk of Adverse Perioperative Events among Surgical Patients Taking Traditional Chinese Herbal Medicines

Abstract

Background The use of traditional Chinese herbal medicines (TCHMs) among the presurgical population is widespread, but their impact on perioperative patient care is unclear. The authors estimated the incidence and risk of TCHM-related perioperative events. Methods In a Hong Kong cohort study, 601 patients undergoing major elective surgery were asked about their Western medicine and TCHM use in the 2 weeks before surgery. Unanticipated perioperative events were noted by attending anesthesiologists, blinded to patients' use of specific TCHMs. Modified Poisson regression models were used to obtain the relative risk of combined endpoints of perioperative events associated with TCHM use. Results Of the 601 patients, 483 patients (80%) took self-prescribed TCHM, and 47 (8%) took TCHM by prescription (with or without self-prescribed TCHM) in the 2 weeks before surgery. The crude incidences of any combined endpoints of preoperative, intraoperative, and postoperative events were 23% (95% confidence interval, 19-26%), 74% (95% confidence interval, 71-78%), and 63% (95% confidence interval, 59-66%), respectively. Compared with nonusers, patients who took TCHM by prescription were more likely to have a preoperative event (adjusted relative risk, 2.21; 95% confidence interval, 1.14-4.29). The authors present four case reports to highlight the effect of TCHM by prescription on prolonged activated partial thromboplastin time and hypokalemia in the preoperative period. In contrast, there was no significant association between the use of any type of TCHM and the occurrence of either intraoperative or postoperative events. Conclusions The use of TCHM by prescription near the time of surgery should be discouraged because of the increased risk of adverse events in the preoperative period.