Malignant Hyperthermia in a Living Organ Donor

Abstract

Living donors are an important source of organs for transplantation. Despite the best efforts of transplant programs to protect donor safety, unpredictable and unpreventable life-threatening issues may arise in the perioperative period. Herein, we provide the first report of a living donor developing malignant hyperthermia (MH) and discuss the unique implications of incidents such as this for living donor programs. A 34-year-old woman volunteered to donate a kidney to her husband. She had previously undergone appendectomy, Caesarean-section, and tubal ligation under general anesthesia without complication. Her medications were omeprazole for mild dyspepsia and iron supplements for anemia related to vegetarian diet. She reported no allergies. Physical examination was normal. Standard laboratory and radiological evaluations were normal. The patient presented for left nephrectomy. General anesthesia was induced with intravenous midazolam, fentanyl, propofol, and rocuronium and maintained with sevoflurane. Initial temperature was 35.8°C through esophageal probe. Surgery proceeded for approximately 2 hours, during which the left renal vessels, ureter, and kidney were fully mobilized using a pure laparoscopic technique. While completing the kidney mobilization, the end-tidal CO2 gradually increased to 60 mm Hg despite increasing the minute ventilation and releasing the pneumoperitoneum. The patient then developed a rise in temperature to 38.5°C, a drop in systolic blood pressure to 60 mm Hg, and ST segment depression on electrocardiogram. Arterial blood gases revealed pH of 6.90 and potassium of 6.83 mmol/L. With a presumptive diagnosis of MH, the nephrectomy was abandoned. Sevoflurane was discontinued, and propofol was initiated. Dantrolene sodium (2.5 mg/kg) was administered, and standard measures were used to treat hypotension, acidosis, and hyperkalemia. Active cooling was performed. The patient stabilized and was transferred to the intensive care unit where dantrolene (2.5 mg/kg every 6 hours) was continued for 24 hours. The patient remained in hospital for 6 days, during which she developed a wound infection, Clostridium difficile diarrhea, and deep vein thrombosis, all of which responded to appropriate therapy. The patient has subsequently been well for 1 year. Application of an MH clinical grading scale to this scenario results in a score of 63, classifying the clinical episode as almost certain MH (1). Genetic testing identified a novel mutation in a skeletal muscle L-type calcium channel, other mutations of which are associated with MH (2). The patient declined open muscle biopsy for definitive diagnosis using the caffeine halothane contracture test. This case emphasizes the variable presentation of MH. Although the syndrome classically manifests soon after first exposure to a triggering agent, departures from this pattern can occur (3, 4). This patient had presumably been exposed to volatile anesthetic agents without complications previously, and the manifestations of MH in this case became apparent 2 hours after exposure to sevoflurane. This case also serves to reinforce a number of important considerations for living donor programs. Despite best efforts to minimize donor complications, it is inevitable that unpredictable and unpreventable life-threatening scenarios will occur, including MH, anaphy-laxis, or acute respiratory distress syndrome. Although the risks of these extremely rare adverse events occurring in ill patients undergoing needed surgery are heavily outweighed by the benefits of a proposed intervention, such an argument is not relevant in the case of living donors. We place great emphasis on fully apprising potential donors about all potential risks involved in donation. In light of cases such as this one, we believe that the informed consent process should include a discussion of potentially catastrophic events however rare they may be. The successful salvage of this patient reflects the importance of prompt recognition and treatment of MH by a multidisciplinary team once the syndrome was suspected. Despite resolution of the acute crisis, a number of secondary complications followed, illustrating the aphorism that “complications beget complications.” For otherwise healthy living donors, in whom the desired outcome is full and normal resumption of preoperative activities, the morbidity associated with numerous minor complications may equal that of an isolated major complication. Although prevention of complications is an important component of patient safety, the ability to “rescue” patients from adverse events is a significant predictor of patient outcomes (5). In reporting the first case of MH developing in a living organ donor, this case highlights the need for transplant programs offering surgery to living donors to actively maintain the resources and expertise necessary to recognize and respond to both common and unusual complications, such that the chance of donor survival is maximized should adverse events occur. Anand Ghanekar1 Robert M. Richardson2 W. Scott Beattie3 1 Department of Surgery Toronto General Hospital University Health Network Toronto, ON, Canada 2 Department of Medicine Toronto General Hospital University Health Network Toronto, ON, Canada 3 Department of Anesthesia Toronto General Hospital University Health Network Toronto, ON, Canada