A suspected case of malignant hyperthermia that was successfully treated with dantrolene administration via nasogastric tube

Corresponding author: Jaegyok Song, M.D., Ph.D., Department of Anesthesiology and Pain Medicine, College of Medicine, Dankook University, 16-5, Anseo-dong, Dongnam-gu, Cheonan 330-715, Korea. Tel: 82-41-550-6819, Fax: 82-41-550-6819, E-mail: [email protected] This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http:// creativecommons.org/licenses/by-nc/3.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. CC We report a suspected case of malignant hyperthermia (MH) during sevoflurane anesthesia which was treated with dantrolene ingestion via nasogastric tube. We obtained a written, informed consent from the patient about using the information of the patient. A 19-yr-old male patient, 75 kg, ASA class I, was scheduled for orbit reconstruction. The patient’s medical history and laboratory findings were unremarkable. There was no familial history of MH, neuromuscular disorder. After applying standard monitoring, anesthesia was induced with fentanyl, lidocaine, propofol, and rocuronium. After tracheal intubation, anesthesia was maintained with oxygen, medical air, sevoflurane, and rocuronium. Baseline data included the following: arterial blood pressure (BP) 120/80 mmHg, heart rate (HR) 90 beats per minute (bpm), SpO2 100%, axillary temperature 35.1C. The vital signs were stable during the surgery. Approximately two hours after the induction of anesthesia, the surgery was expected to end within 30 minutes, and sevo flurane was changed to desflurane in order to facilitate recovery. After 10 minutes, end tidal CO2 (EtCO2) suddenly began to increase from 37 to 72 mmHg, and vital signs were also changed (axillary temperature; 36.1C to 37.4C, BP; 130/70 mmHg to 160/100 mmHg, HR; 80 bpm to 155 bpm). Desflurane was discontinued, 100% oxygen (flow rate 10 L/min) was given, corrugate circuit and CO2 canister were changed, and the ventilatory rate was doubled. Midazolam 5 mg was intravenously injected, and propofol infusion was started. An arterial catheter was inserted, and arterial blood gas analysis (ABGA) showed the followings: pH 7.15, PaCO2 58 mmHg, PaO2 229 mmHg, base excess -9.6 mmol/L (Table 1). The surgery was completed at 2 hours and 35 minutes after the induction of anesthesia. After completion of surgery, a Foley catheter and nasogastric tube were inserted, and the body temperature (BT) of tympanic membrane was 38.4C. Therapy for MH was initiated and included external cooling with cooling pad, cold intravenous (IV) fluids, forced diuresis, and bladder irrigation with cold saline. Since we did not have IV dantrolene, we tried to contact the hospital that stored dantrolene for the hospitals in our province, but they did not have any available dantrolene. Since there was no other choice, we created a dantrolene suspension by mixing 12 dantrolene capsules for oral medication (4 mg/kg, total 300 mg) in 50 ml of warm sterile water and injected it via nasogastric tube 5 minutes after the end of surgery. After 30 minutes, another dose of dantrolene suspension 100 mg was injected. Thirty minutes after the first dose of dantrolene ingestion, the patient’s condition was gradually stabilized: EtCO2 34 mmHg, BT 37.4C, BP 130/80 mmHg, and heart rate 94 bpm. ABGA was normalized (Table 1). One hour after the last dose of dantrolene, we confirmed the patient’s condition as stable and stopped propofol infusion. The patient recovered from general anesthesia and transferred to the intensive care unit (ICU) after extubation. One hour after ICU admission, BT elevated to 38.2C again and cooling was continued with additional