Critically High Carboxyhemoglobin Level following Extensive Hysteroscopic Myomectomy

Studies have demonstrated that during hysteroscopic myomectomy with bipolar diathermy, carbon monoxide is produced and enters the patient's circulation. However, little is known regarding the immediate or long-term sequelae of transient rises in carboxyhemoglobin levels during hysteroscopic surgery. This paper aims to suggest recommendations for acute evaluation, management, patient counseling, and future research. We present a case of a 36-year-old woman (Gravida 0, Para 0) with abnormal uterine bleeding-leiomyoma and resultant anemia, undergoing hysteroscopic resection of a large submucous myoma. During surgery, the patient was found to have a critically elevated level of carboxyhemoglobin and accompanying electrocardiogram derangements. She was managed with prolonged intubation, 100% O₂, and trending of her carboxyhemoglobin levels before extubation. This demonstrates the importance of being cognizant of the potentially toxic gaseous byproducts of bipolar resection and of including intravasation of these byproducts in one's consideration of patient safety during extensive resections. Bipolar hysteroscopic resection of large leiomyomas may result in critically high carboxyhemoglobin levels, which can impair end-organ oxygen delivery with resultant ischemia; the risks of myocardial ischemia should be discussed with the anesthesia team before attempting an extensive resection. Electrocardiogram changes indicative of ischemia should prompt discontinuation of the case. Finally, carboxyhemoglobin poisoning should be included in the differential diagnosis of patients who demonstrate longer-than-expected anesthesia recovery times after bipolar resection of large submucous leiomyomas, and they should be managed with repeat evaluation of carboxyhemoglobin levels, supplemental oxygen, and cardiac monitoring.