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.

Standardized protocols for photocarcinogenesis safety testing.

Solar ultraviolet radiation (UVR) is recognized as a major cause of non-melanoma skin cancer in man. Skin cancer occurs most frequently in the most heavily exposed areas and correlates with degree of outdoor exposure. The incidence of skin cancer is also increased by contact with photosensitizing drugs and chemicals such as psoralens, coal tars and petroleum stocks. Other substances which do not act as photosensitizers, such as immunosuppressants taken by organ transplant recipients, also increase the risk of skin cancer. The U.S. Food and Drug Administration requests, on a case-by-case basis, that risk of enhanced photocarcinogenesis is assessed for many classes of drugs. Health Canada's Therapeutic Products Programme has issued a Notice of Intent to regulate pharmaceutical products which may enhance carcinogenicity of the skin induced by ultraviolet radiation. Other national regulatory agencies review such data when they exist, but their own requirements emphasize batteries of short-term in vitro and in vivo tests. While they may support drug development strategies, short-term tests have yet to be validated as predictors of the ability of drugs or chemicals to enhance photocarcinogenesis. Published protocols now describe study designs and procedures capable of determining whether test agents enhance the rate of formation of UVR-induced skin tumors.