Austin Peay State University
Clinical Pathway: Malignant Hyperthermia
Mr. F, a healthy 34-year-old man, is admitted to a local hospital for a routine cholecystectomy. A preoperative assessment by the nurse anesthetist reveals no complications with prior surgeries and a familial history of anesthetic complications, but Mr. F is unsure of what the complications were called. During surgery, no adverse effects are noted by the surgical team. After successful removal of the gallbladder and an unremarkable anesthetic reversal, Mr. F is transported to the post anesthesia care unit (PACU) and monitored before being transferred to medical-surgical unit. Vital signs are as follows: heart rate, 75/min; blood pressure, 127/82 mm Hg; respiratory rate, 16/min; oxygen saturation, 100% on 2L of O² via nasal cannula; body temperature, 36.9°C. When Mr. F arrives to the PACU, the receiving nurse notices an increase in his heart rate to 91/min and an increase in respirations to 21/min. After administering a 3-mg IV bolus of morphine sulfate for pain and increasing oxygen delivery to 4L/min via nasal cannula, the nurse continues to see a gradual increase in heart rate and respirations as well as an increase in blood pressure and body temperature. Ten minutes later, Mr. F’s vital signs are now as follows: heart rate, 114/min; blood pressure 147/92 mm Hg; respirations, 25/min; oxygen saturation, 98% on 4L of oxygen via nasal cannula; and body temperature, 38.8°C. The nurse again treats with a 3-mg IV bolus of morphine sulfate and increases his oxygen to 5L by mask. During the nurse’s assessment, she notices Mr. F’s body temperature is increasing. As the surgeon and the certified registered nurse anesthetist are called to report Mr. F’s condition, the patient begins to experience muscle rigidity of the trunk. At this point, vital signs are as follows: heart rate, 127/min; blood pressure, 167/101 mm Hg; respirations, 31/min; oxygen saturation, 89% on 5L oxygen via mask; and body temperature, 39.5°C. Mr. F’s EKG begins to show ventricular ectopy.
II. Precipitating Factors:
A. Past medical history – The patient reports a benign medical history. Individuals that have not been identified as susceptible to malignant hyperthermia or had a past episode of the disorder will likely not be identified during a routine, thorough preoperative assessment (Denborough, 1998). B. Past surgical history- The patient reports no complications with prior surgical procedures. Individuals susceptible to malignant hyperthermia (MH) who have undergone a previously uncomplicated general anesthetic procedure with an inhaled volatile anesthetic or muscle relaxant, such as succinylcholine, may develop malignant hyperthermia during a subsequent anesthetic procedure (Denborough, 1998). C. Family history – Mr. F reported a family member had experienced complications with anesthesia, but was unable to provide any further information. Susceptibility to malignant hyperthermia is an inherited genetic disorder manifested as an autosomal dominant trait. The disorder is manifested by exposure of susceptible individuals to triggering medications. Without such exposure, it is usually impossible to identify MH-susceptible patients unless there is a personal or family history suggestive of MH (McCance, Huether, Brashers, & Rote, 2010).
III. History of Present Illness
A possible diagnosis of malignant hyperthermia is made by the nurse anesthetist, the malignant hyperthermia cart is brought to the bedside, and Mr. F is immediately treated with 2.5 mg/kg of dantrolene IV and 2 mEq/kg of bicarbonate and is reintubated. Serial blood gas analyses are ordered, along with coagulation studies, a complete blood cell count and measurements of electrolytes, creatine kinase, lactate, and myoglobin levels. Sequential samples are also...