CASE REPORT
Malignant hyperthermia in a trauma patient Valerie Carpenter; Brenton LaRiccia, MS, RPA-C; Peter J. Papadakos, MD, FCCM, FAARC
ABSTRACT Malignant hyperthermia is a life-threatening disorder caused by exposure to certain anesthetics. Prompt recognition and intervention is crucial. This article focuses on preoperative patient screening as well as perioperative and postoperative recognition and management. Keywords: malignant hyperthermia, volatile, anesthesia, neuromuscular blockers, end-tidal carbon dioxide, dantrolene
CASE A 28-year-old woman was brought by ambulance to a level I trauma center after a motor vehicle accident. She had a left hip dislocation with acetabular fracture, midshaft femur fracture, bilateral rib fractures, nondisplaced fracture of L1-L3 transverse processes, bilateral pneumothorax and pulmonary contusions, severe liver laceration, contusions of the kidney, and multiple lacerations. The patient was admitted to the burn/trauma ICU for resuscitation and close hemodynamic monitoring. The next day, she underwent repair of the lower extremity fracture; desflurane was administered with no complications. Subsequently, the patient underwent additional orthopedic surgery using desflurane with no anesthesiarelated complications. After several days in the ICU, the patient returned to the OR for open reduction and internal fixation of the left acetabulum. She was anesthetized with desflurane and placed in the prone position. Her preoperative arterial blood gas (ABG) analysis indicated a potassium level of 4.4 mEq/L and a pH of 7.39. During the procedure, the patient acutely developed hyperkalemia with a mixed metabolic and respiratory acidosis. A repeat ABG analysis revealed potassium of 6.7 mEq/L and pH of 7.30. Her urine output was noted to be decreasing in quantity and amber-colored. Valerie Carpenter is a student in the PA program at Daemen College in Amherst, N.Y. Brenton LaRiccia is lead PA in the Kessler Family Burn/Trauma ICU at the University of Rochester (N.Y.) Medical Center. Peter J. Papadakos is director of critical care medicine and a professor of anesthesiology, surgery, neurosurgery, and neurology at the University of Rochester Medical Center. The authors have disclosed no potential conflicts of interest, financial or otherwise. DOI: 10.1097/01.JAA.0000453862.54700.78 Copyright © 2015 American Academy of Physician Assistants
JAAPA Journal of the American Academy of Physician Assistants
Key points Malignant hyperthermia is a result of genetic mutations affecting the regulation of calcium release and muscle contractility. Known triggering agents include inhaled halogenated volatile anesthetics and neuromuscular blocking agents. The gold standard diagnostic test is the skeletal muscle contracture test. Complications include acidosis, hyperthermia, electrolyte imbalances, DIC, renal failure, and rhabdomyolysis.
She was treated for hyperkalemia, started on an insulin infusion, and administered bicarbonate and calcium. About 40 minutes after hyperkalemia treatment was initiated, the patient experienced an abrupt onset of narrow-complex bradycardia with a heart rate of 27 beats per minute and peaked T waves on the cardiac monitor. An OR STAT condition was called and the procedure was aborted due to hyperkalemic cardiac arrest. The patient was turned supine and given IV epinephrine and additional doses of bicarbonate and calcium. A repeat ABG analysis, drawn after the patient returned to baseline heart rate, indicated a severe mixed acidosis with a pH level of 6.89, Paco2 of 121 mm Hg, and potassium level of 9.1 mEq/L. The situation was determined to be an evolving malignant hyperthermia crisis and a malignant hyperthermia protocol was initiated. The patient received an initial dose of 240 mg of dantrolene, based on a 2.5 mg/kg dose, and a second dantrolene dose of 60 mg before transfer from the OR to the burn/trauma ICU. She also was given dextrose and 4 units of packed red blood cells. Active cooling was initiated with full body exposure, decreased room temperature, a temperature-regulating blanket, and ice bags packed in the axillae and over the femoral vessels. In the burn/trauma ICU, the patient received IV resuscitation and continued dantrolene therapy according to the malignant hyperthermia protocol. She was hemodynamically unstable, which prevented hemodialysis, so emergent continuous veno-venous hemofiltration (CVVH) therapy was started to manage her hyperkalemia and new-onset acute kidney injury. The massive transfusion protocol was initiated for lower extremity hemorrhage with associated disseminated intravascular coagulation (DIC). www.JAAPA.com
Copyright © 2015 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
45
CASE REPORT
DISCUSSION Since the first report of malignant hyperthermia by Denborough in 1960, understanding of this life-threatening disorder has greatly increased.1 As a result, mortality has decreased from 70% in the 1970s to less than 5% per episode.1-4 Malignant hyperthermia is reported as frequently as 1 in 2,000 to 1 in 150,000 administrations of general anesthesia, with a 2.5 to 4.5 times higher incidence in men than in women.2-5 Pathophysiology Malignant hyperthermia is a rare, autosomal-dominant myopathytriggered reaction to inhaled halogenated volatile anesthetics such as halothane or depolarizing neuromuscular blocking agents such as succinylcholine.1-3,6,7 Malignant hyperthermia results from disordered calcium regulation by the sarcoplasmic reticulum of skeletal muscle. Mutations FIGURE 1. Excitation-contraction coupling and malignant hyperthermia. (ATP, adenosine triphosphate; FA, fatty acids; TG, triglycerides.) linked to malignant hyperthermia have A rise in the patient’s end-tidal carbon dioxide (Etco2) been identified within the calcium release channel of the sarcoplasmic reticulum (ryanodine receptor type 1 [RYR1]) concentration is often the earliest indication of malignant and CACNA1S, a subunit of the dihydropyridine receptor hyperthermia.1 Other early clinical manifestations include associated with calcium channel activation.2,6-8 During a generalized muscle rigidity, tachypnea, tachycardia, carmalignant hyperthermia crisis, these mutations cause diac dysrhythmias, and cutaneous changes such as genuncontrolled release of calcium from the sarcoplasmic eralized flushing, cyanosis, or skin mottling. Masseter reticulum, leading to prolonged muscle fiber contraction; muscle spasm is an early sign of malignant hyperthermia rapid depletion of adenosine triphosphate; and concomitant after succinylcholine administration, although mild masoxygen consumption, heat production, and cellular break- seter spasm can be a normal response to succinylcholine.10 down. This series of events leads to a hypermetabolic During malignant hyperthermia, patients develop a mixed emergency including acidosis, electrolyte imbalances, metabolic and respiratory acidosis with associated hyperhyperthermia, DIC, and cardiac dysrhythmias.2 kalemia, hyperphosphatemia, and hypocalcemia due to Diagnostic testing The gold standard test for identify- skeletal muscle cell breakdown. Rhabdomyolysis may ing susceptibility to malignant hyperthermia is the in vitro result in myoglobinemia, myoglobinuria, elevated serum skeletal muscle contracture test. This test assesses the creatine phosphokinase levels, and subsequent renal failmuscular contractility of live thigh muscle from biopsy ure.1,2,5 Severe, rapidly progressing hyperthermia often in response to halothane and caffeine exposure. Exposure occurs late in the development of malignant hyperthermia. to halothane and caffeine increases the skeletal muscle Elevated core body temperature is associated with increased contractility in patients susceptible to malignant hyper- oxygen consumption (to two to three times the normal thermia.1,2,6,8 Genetic testing for the mutations associated rate) and DIC.2 Shock, ventricular fibrillation, severe aciwith malignant hyperthermia is available, but has a low dosis, or cardiac arrest may occur as quickly as 20 minutes detection rate.2,4 Increased susceptibility has also been after the onset of hyperthermia.2,5 Any combination of the identified in patients with heat stroke and exercise-induced manifestations of malignant hyperthermia can result in rhabdomyolysis.3 sudden, unexplained cardiac arrest.1,2 Clinical presentation The clinical manifestations of Differential diagnosis of malignant hyperthermia malignant hyperthermia usually present within several includes neuroleptic malignant syndrome, thyroid storm, minutes to a few hours of the patient’s initial exposure to pheochromocytoma, heat stroke, serotonin syndrome, the triggering agent. However, about 50% of patients septicemia, and cocaine or ecstasy (3,4-methylenedioxysusceptible to malignant hyperthermia had at least one methamphetamine or MDMA) overdose.1,2,5 2,9 previous unremarkable exposure to general anesthetics. This may be due to variations in the concentration of the TREATMENT anesthetic, the duration of exposure, and the patient’s Initial treatment of malignant hyperthermia consists degree of susceptibility.1 of discontinuing the triggering agent; administering 46
www.JAAPA.com
Volume 28 • Number 1 • January 2015
Copyright © 2015 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Malignant hyperthermia in a trauma patient
dantrolene; hyperventilating the patient; regulating body temperature; and controlling hyperkalemia, acidosis, and cardiac dysrhythmias. Dantrolene, originally synthesized as a possible antibiotic, is a skeletal muscle relaxant that inhibits the excitation-contraction in skeletal muscle without affecting muscle electrical properties.1 Administer dantrolene (2.5 mg/kg) rapidly, preferably through a large-bore IV device, to prevent further destruction by contracture of susceptible muscle. Dantrolene doses may be repeated every 5 minutes, and should be titrated to tachycardia and hypercarbia, with a suggested maximum dose of 10 mg/kg. Start hyperventilation at two to three times the normal minute ventilation with 100% oxygen to lower Etco2 concentration, and assist in managing acidosis and hyperkalemia. Administer IV bicarbonate, insulin, dextrose, and calcium to control metabolic acidosis and hyperkalemia. Cardiac dysrhythmias associated with malignant hyperthermia usually respond well to the management of acidosis and hyperkalemia. Persistent dysrhythmias may require administration of antiarrhythmic drugs such as amiodarone and lidocaine.4,5,10 Do not administer calcium channel blockers to patients susceptible to malignant hyperthermia because these drugs can cause increased calcium release and interact with dantrolene, causing hyperkalemia and cardiac arrest.2,7 Use aggressive cooling techniques, such as use of cold IV fluids, nasogastric lavage with iced solutions, and placement of ice packs on the neck, groin, and axillae to achieve a core body temperature of 38° C (100.4° F). Controlling core body temperature helps prevent DIC, which most frequently occurs when body temperature exceeds 41° C (105.8° F).4 Treat acute rhabdomyolysis with crystalloid fluid resuscitation and diuretics (such as furosemide and mannitol) to maintain a urine output greater than 2 mL/kg/hour.5 In some patients with rhabdomyolysis, myoglobin accumulation in the renal tubules may lead to acute renal failure requiring renal replacement therapy. Closely monitor the patient for myoglobinuria. Also monitor the patient’s core temperature and arterial or venous blood gases, electrolytes, coagulation factors, serum myoglobin, and creatine kinase levels.2 After a malignant hyperthermia crisis, the patient should be admitted to an ICU to continue treatment and monitoring for at least 36 hours. Dantrolene therapy should be continued as a 1 mg/kg bolus every 4 hours or as a 0.25 mg/kg/hour continuous infusion for 24 to 48 hours. Report episodes of malignant hyperthermia to registry of the Malignant Hyperthermia Association of the United States (MHAUS, http://www.mhaus.org). MHAUS also offers educational resources and a 24-hour crisis hotline for malignant hyperthermia management guidance.10 JAAPA Journal of the American Academy of Physician Assistants
PREVENTION A thorough preoperative anesthetic history to determine the possibility of malignant hyperthermia susceptibility in the patient or a family member is essential to preventing malignant hyperthermia. In patients with known or suspected susceptibility, avoid general anesthesia and sedation and use alternate anesthetic techniques, such as epidural, regional, or local anesthesia. If general anesthesia is required, avoid drugs known to trigger malignant hyperthermia (halothane, desflurane, enflurane, isoflurane, sevoflurane, methoxyflurane, ether, and succinylcholine) and administer anesthesia through an anesthesia machine absent of all volatile anesthetic residue.10 CONCLUSION During the postoperative period, the patient remained hemodynamically unstable, requiring aggressive fluid and blood resuscitation and multiple vasopressors. The patient was critically ill in fulminant liver failure, DIC, acidosis, and acute kidney injury despite ongoing CVVH therapy. The patient experienced several episodes of bradycardia and oxygen desaturation requiring epinephrine, atropine, and CPR. On the fourth postoperative day, the patient became acutely bradycardic with complete loss of pulses, and multiple rounds of advanced cardiovascular life support were unsuccessful in returning circulation. JAAPA REFERENCES 1. Denborough M. Malignant hyperthermia. Lancet. 1998;352 (9134):1131-1136. 2. Stratman RC, Flynn JD, Hatton KW. Malignant hyperthermia: a pharmacogenetic disorder. Orthopedics. 2009;32(11):835-838. 3. Brady JE, Sun LS, Rosenberg H, Li G. Prevalence of malignant hyperthermia due to anesthesia in New York State, 2001-2005. Anesth Analg. 2009;109(4):1162-1166. 4. Rosenberg H, Davis M, James D, et al. Malignant hyperthermia. Orphanet J Rare Dis. 2007;2:21. 5. Glahn KP, Ellis FR, Halsall PJ, et al. Recognizing and managing a malignant hyperthermia crisis: guidelines from the European Malignant Hyperthermia Group. Br J Anaesth. 2010;105(4): 417-420. 6. O’Sullivan GH, McIntosh JM, Heffron JJ. Abnormal uptake and release of Ca2+ ions from human malignant hyperthermia-susceptible sarcoplasmic reticulum. Biochem Pharmacol. 2001;61(12): 1479-1485. 7. Migita T, Mukaida K, Yasuda T, et al. Calcium channel blockers are inadequate for malignant hyperthermia crisis. J Anesth. 2012;26(4):579-584. 8. Carpenter D, Ringrose C, Leo V, et al. The role of CACNA1S in predisposition to malignant hyperthermia. BMC Med Genet. 2009;10:104. 9. Larach MG, Gronert GA, Allen GC, et al. Clinical presentation, treatment, and complications of malignant hyperthermia in North America from 1987 to 2006. Anesth Analg. 2010;110(2): 498-507. 10. Managing an MH crisis. Malignant Hyperthermia Association of the United States. http://www.mhaus.org. Accessed December 3, 2013. www.JAAPA.com
Copyright © 2015 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
47
Malignant hyperthermia in a trauma patient Valerie Carpenter; Brenton LaRiccia, MS, RPA-C; Peter J. Papadakos, MD, FCCM, FAARC
ABSTRACT Malignant hyperthermia is a life-threatening disorder caused by exposure to certain anesthetics. Prompt recognition and intervention is crucial. This article focuses on preoperative patient screening as well as perioperative and postoperative recognition and management. Keywords: malignant hyperthermia, volatile, anesthesia, neuromuscular blockers, end-tidal carbon dioxide, dantrolene
CASE A 28-year-old woman was brought by ambulance to a level I trauma center after a motor vehicle accident. She had a left hip dislocation with acetabular fracture, midshaft femur fracture, bilateral rib fractures, nondisplaced fracture of L1-L3 transverse processes, bilateral pneumothorax and pulmonary contusions, severe liver laceration, contusions of the kidney, and multiple lacerations. The patient was admitted to the burn/trauma ICU for resuscitation and close hemodynamic monitoring. The next day, she underwent repair of the lower extremity fracture; desflurane was administered with no complications. Subsequently, the patient underwent additional orthopedic surgery using desflurane with no anesthesiarelated complications. After several days in the ICU, the patient returned to the OR for open reduction and internal fixation of the left acetabulum. She was anesthetized with desflurane and placed in the prone position. Her preoperative arterial blood gas (ABG) analysis indicated a potassium level of 4.4 mEq/L and a pH of 7.39. During the procedure, the patient acutely developed hyperkalemia with a mixed metabolic and respiratory acidosis. A repeat ABG analysis revealed potassium of 6.7 mEq/L and pH of 7.30. Her urine output was noted to be decreasing in quantity and amber-colored. Valerie Carpenter is a student in the PA program at Daemen College in Amherst, N.Y. Brenton LaRiccia is lead PA in the Kessler Family Burn/Trauma ICU at the University of Rochester (N.Y.) Medical Center. Peter J. Papadakos is director of critical care medicine and a professor of anesthesiology, surgery, neurosurgery, and neurology at the University of Rochester Medical Center. The authors have disclosed no potential conflicts of interest, financial or otherwise. DOI: 10.1097/01.JAA.0000453862.54700.78 Copyright © 2015 American Academy of Physician Assistants
JAAPA Journal of the American Academy of Physician Assistants
Key points Malignant hyperthermia is a result of genetic mutations affecting the regulation of calcium release and muscle contractility. Known triggering agents include inhaled halogenated volatile anesthetics and neuromuscular blocking agents. The gold standard diagnostic test is the skeletal muscle contracture test. Complications include acidosis, hyperthermia, electrolyte imbalances, DIC, renal failure, and rhabdomyolysis.
She was treated for hyperkalemia, started on an insulin infusion, and administered bicarbonate and calcium. About 40 minutes after hyperkalemia treatment was initiated, the patient experienced an abrupt onset of narrow-complex bradycardia with a heart rate of 27 beats per minute and peaked T waves on the cardiac monitor. An OR STAT condition was called and the procedure was aborted due to hyperkalemic cardiac arrest. The patient was turned supine and given IV epinephrine and additional doses of bicarbonate and calcium. A repeat ABG analysis, drawn after the patient returned to baseline heart rate, indicated a severe mixed acidosis with a pH level of 6.89, Paco2 of 121 mm Hg, and potassium level of 9.1 mEq/L. The situation was determined to be an evolving malignant hyperthermia crisis and a malignant hyperthermia protocol was initiated. The patient received an initial dose of 240 mg of dantrolene, based on a 2.5 mg/kg dose, and a second dantrolene dose of 60 mg before transfer from the OR to the burn/trauma ICU. She also was given dextrose and 4 units of packed red blood cells. Active cooling was initiated with full body exposure, decreased room temperature, a temperature-regulating blanket, and ice bags packed in the axillae and over the femoral vessels. In the burn/trauma ICU, the patient received IV resuscitation and continued dantrolene therapy according to the malignant hyperthermia protocol. She was hemodynamically unstable, which prevented hemodialysis, so emergent continuous veno-venous hemofiltration (CVVH) therapy was started to manage her hyperkalemia and new-onset acute kidney injury. The massive transfusion protocol was initiated for lower extremity hemorrhage with associated disseminated intravascular coagulation (DIC). www.JAAPA.com
Copyright © 2015 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
45
CASE REPORT
DISCUSSION Since the first report of malignant hyperthermia by Denborough in 1960, understanding of this life-threatening disorder has greatly increased.1 As a result, mortality has decreased from 70% in the 1970s to less than 5% per episode.1-4 Malignant hyperthermia is reported as frequently as 1 in 2,000 to 1 in 150,000 administrations of general anesthesia, with a 2.5 to 4.5 times higher incidence in men than in women.2-5 Pathophysiology Malignant hyperthermia is a rare, autosomal-dominant myopathytriggered reaction to inhaled halogenated volatile anesthetics such as halothane or depolarizing neuromuscular blocking agents such as succinylcholine.1-3,6,7 Malignant hyperthermia results from disordered calcium regulation by the sarcoplasmic reticulum of skeletal muscle. Mutations FIGURE 1. Excitation-contraction coupling and malignant hyperthermia. (ATP, adenosine triphosphate; FA, fatty acids; TG, triglycerides.) linked to malignant hyperthermia have A rise in the patient’s end-tidal carbon dioxide (Etco2) been identified within the calcium release channel of the sarcoplasmic reticulum (ryanodine receptor type 1 [RYR1]) concentration is often the earliest indication of malignant and CACNA1S, a subunit of the dihydropyridine receptor hyperthermia.1 Other early clinical manifestations include associated with calcium channel activation.2,6-8 During a generalized muscle rigidity, tachypnea, tachycardia, carmalignant hyperthermia crisis, these mutations cause diac dysrhythmias, and cutaneous changes such as genuncontrolled release of calcium from the sarcoplasmic eralized flushing, cyanosis, or skin mottling. Masseter reticulum, leading to prolonged muscle fiber contraction; muscle spasm is an early sign of malignant hyperthermia rapid depletion of adenosine triphosphate; and concomitant after succinylcholine administration, although mild masoxygen consumption, heat production, and cellular break- seter spasm can be a normal response to succinylcholine.10 down. This series of events leads to a hypermetabolic During malignant hyperthermia, patients develop a mixed emergency including acidosis, electrolyte imbalances, metabolic and respiratory acidosis with associated hyperhyperthermia, DIC, and cardiac dysrhythmias.2 kalemia, hyperphosphatemia, and hypocalcemia due to Diagnostic testing The gold standard test for identify- skeletal muscle cell breakdown. Rhabdomyolysis may ing susceptibility to malignant hyperthermia is the in vitro result in myoglobinemia, myoglobinuria, elevated serum skeletal muscle contracture test. This test assesses the creatine phosphokinase levels, and subsequent renal failmuscular contractility of live thigh muscle from biopsy ure.1,2,5 Severe, rapidly progressing hyperthermia often in response to halothane and caffeine exposure. Exposure occurs late in the development of malignant hyperthermia. to halothane and caffeine increases the skeletal muscle Elevated core body temperature is associated with increased contractility in patients susceptible to malignant hyper- oxygen consumption (to two to three times the normal thermia.1,2,6,8 Genetic testing for the mutations associated rate) and DIC.2 Shock, ventricular fibrillation, severe aciwith malignant hyperthermia is available, but has a low dosis, or cardiac arrest may occur as quickly as 20 minutes detection rate.2,4 Increased susceptibility has also been after the onset of hyperthermia.2,5 Any combination of the identified in patients with heat stroke and exercise-induced manifestations of malignant hyperthermia can result in rhabdomyolysis.3 sudden, unexplained cardiac arrest.1,2 Clinical presentation The clinical manifestations of Differential diagnosis of malignant hyperthermia malignant hyperthermia usually present within several includes neuroleptic malignant syndrome, thyroid storm, minutes to a few hours of the patient’s initial exposure to pheochromocytoma, heat stroke, serotonin syndrome, the triggering agent. However, about 50% of patients septicemia, and cocaine or ecstasy (3,4-methylenedioxysusceptible to malignant hyperthermia had at least one methamphetamine or MDMA) overdose.1,2,5 2,9 previous unremarkable exposure to general anesthetics. This may be due to variations in the concentration of the TREATMENT anesthetic, the duration of exposure, and the patient’s Initial treatment of malignant hyperthermia consists degree of susceptibility.1 of discontinuing the triggering agent; administering 46
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Volume 28 • Number 1 • January 2015
Copyright © 2015 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Malignant hyperthermia in a trauma patient
dantrolene; hyperventilating the patient; regulating body temperature; and controlling hyperkalemia, acidosis, and cardiac dysrhythmias. Dantrolene, originally synthesized as a possible antibiotic, is a skeletal muscle relaxant that inhibits the excitation-contraction in skeletal muscle without affecting muscle electrical properties.1 Administer dantrolene (2.5 mg/kg) rapidly, preferably through a large-bore IV device, to prevent further destruction by contracture of susceptible muscle. Dantrolene doses may be repeated every 5 minutes, and should be titrated to tachycardia and hypercarbia, with a suggested maximum dose of 10 mg/kg. Start hyperventilation at two to three times the normal minute ventilation with 100% oxygen to lower Etco2 concentration, and assist in managing acidosis and hyperkalemia. Administer IV bicarbonate, insulin, dextrose, and calcium to control metabolic acidosis and hyperkalemia. Cardiac dysrhythmias associated with malignant hyperthermia usually respond well to the management of acidosis and hyperkalemia. Persistent dysrhythmias may require administration of antiarrhythmic drugs such as amiodarone and lidocaine.4,5,10 Do not administer calcium channel blockers to patients susceptible to malignant hyperthermia because these drugs can cause increased calcium release and interact with dantrolene, causing hyperkalemia and cardiac arrest.2,7 Use aggressive cooling techniques, such as use of cold IV fluids, nasogastric lavage with iced solutions, and placement of ice packs on the neck, groin, and axillae to achieve a core body temperature of 38° C (100.4° F). Controlling core body temperature helps prevent DIC, which most frequently occurs when body temperature exceeds 41° C (105.8° F).4 Treat acute rhabdomyolysis with crystalloid fluid resuscitation and diuretics (such as furosemide and mannitol) to maintain a urine output greater than 2 mL/kg/hour.5 In some patients with rhabdomyolysis, myoglobin accumulation in the renal tubules may lead to acute renal failure requiring renal replacement therapy. Closely monitor the patient for myoglobinuria. Also monitor the patient’s core temperature and arterial or venous blood gases, electrolytes, coagulation factors, serum myoglobin, and creatine kinase levels.2 After a malignant hyperthermia crisis, the patient should be admitted to an ICU to continue treatment and monitoring for at least 36 hours. Dantrolene therapy should be continued as a 1 mg/kg bolus every 4 hours or as a 0.25 mg/kg/hour continuous infusion for 24 to 48 hours. Report episodes of malignant hyperthermia to registry of the Malignant Hyperthermia Association of the United States (MHAUS, http://www.mhaus.org). MHAUS also offers educational resources and a 24-hour crisis hotline for malignant hyperthermia management guidance.10 JAAPA Journal of the American Academy of Physician Assistants
PREVENTION A thorough preoperative anesthetic history to determine the possibility of malignant hyperthermia susceptibility in the patient or a family member is essential to preventing malignant hyperthermia. In patients with known or suspected susceptibility, avoid general anesthesia and sedation and use alternate anesthetic techniques, such as epidural, regional, or local anesthesia. If general anesthesia is required, avoid drugs known to trigger malignant hyperthermia (halothane, desflurane, enflurane, isoflurane, sevoflurane, methoxyflurane, ether, and succinylcholine) and administer anesthesia through an anesthesia machine absent of all volatile anesthetic residue.10 CONCLUSION During the postoperative period, the patient remained hemodynamically unstable, requiring aggressive fluid and blood resuscitation and multiple vasopressors. The patient was critically ill in fulminant liver failure, DIC, acidosis, and acute kidney injury despite ongoing CVVH therapy. The patient experienced several episodes of bradycardia and oxygen desaturation requiring epinephrine, atropine, and CPR. On the fourth postoperative day, the patient became acutely bradycardic with complete loss of pulses, and multiple rounds of advanced cardiovascular life support were unsuccessful in returning circulation. JAAPA REFERENCES 1. Denborough M. Malignant hyperthermia. Lancet. 1998;352 (9134):1131-1136. 2. Stratman RC, Flynn JD, Hatton KW. Malignant hyperthermia: a pharmacogenetic disorder. Orthopedics. 2009;32(11):835-838. 3. Brady JE, Sun LS, Rosenberg H, Li G. Prevalence of malignant hyperthermia due to anesthesia in New York State, 2001-2005. Anesth Analg. 2009;109(4):1162-1166. 4. Rosenberg H, Davis M, James D, et al. Malignant hyperthermia. Orphanet J Rare Dis. 2007;2:21. 5. Glahn KP, Ellis FR, Halsall PJ, et al. Recognizing and managing a malignant hyperthermia crisis: guidelines from the European Malignant Hyperthermia Group. Br J Anaesth. 2010;105(4): 417-420. 6. O’Sullivan GH, McIntosh JM, Heffron JJ. Abnormal uptake and release of Ca2+ ions from human malignant hyperthermia-susceptible sarcoplasmic reticulum. Biochem Pharmacol. 2001;61(12): 1479-1485. 7. Migita T, Mukaida K, Yasuda T, et al. Calcium channel blockers are inadequate for malignant hyperthermia crisis. J Anesth. 2012;26(4):579-584. 8. Carpenter D, Ringrose C, Leo V, et al. The role of CACNA1S in predisposition to malignant hyperthermia. BMC Med Genet. 2009;10:104. 9. Larach MG, Gronert GA, Allen GC, et al. Clinical presentation, treatment, and complications of malignant hyperthermia in North America from 1987 to 2006. Anesth Analg. 2010;110(2): 498-507. 10. Managing an MH crisis. Malignant Hyperthermia Association of the United States. http://www.mhaus.org. Accessed December 3, 2013. www.JAAPA.com
Copyright © 2015 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
47
