What anesthetics should be used for a patient with Duchenne Muscular Dystrophy (DMD) and Polymyositis undergoing a tendon lengthening procedure?

Anesthetic Management for Tendon Lengthening in Duchenne Muscular Dystrophy with Polymyositis

Use total intravenous anesthesia (TIVA) with propofol and short-acting opioids (remifentanil or fentanyl) without any depolarizing muscle relaxants, as succinylcholine is absolutely contraindicated due to risk of fatal hyperkalemic cardiac arrest. 1

Critical Contraindications

Absolutely Avoid Succinylcholine

• Succinylcholine causes acute rhabdomyolysis, massive potassium release, and hyperkalemic cardiac arrest within minutes in DMD patients 1, 2
• Cardiac arrest can occur immediately after injection, even in previously undiagnosed cases 2, 3
• The mechanism involves disruption of unstable dystrophic muscle cell membranes with massive potassium efflux 1, 2

Avoid or Use Extreme Caution with Volatile Anesthetics

• Inhaled agents (halothane, isoflurane, sevoflurane) are associated with extreme hyperthermic events, rhabdomyolysis, and sudden death in DMD patients 1
• These reactions mimic malignant hyperthermia but represent a distinct genetic disease process 1

Recommended Anesthetic Technique

Primary Approach: Total Intravenous Anesthesia (TIVA)

• Propofol for induction and maintenance combined with remifentanil or fentanyl for analgesia 1
• This technique has been validated in multiple case series with 232 patients showing no severe complications 4, 5, 6
• Successful tracheal intubation can be achieved without muscle relaxants using adequate propofol and opioid dosing 4, 5

If Muscle Relaxation Required

• Use non-depolarizing agents only: rocuronium (≥0.9 mg/kg) or other non-depolarizing relaxants 2, 7
• Rocuronium provides rapid sequence intubation capability with dramatically superior safety profile compared to succinylcholine 2
• Have sugammadex immediately available for reversal if rocuronium is used 7
• Employ neuromuscular monitoring as DMD patients show increased sensitivity to all muscle relaxants 2, 6

Essential Perioperative Monitoring

Intraoperative Requirements

• Continuous SpO₂ monitoring (maintain ≥95%) 1
• Blood or end-tidal CO₂ monitoring whenever possible 1
• Have ICU bed available for postoperative care 1
• Experienced anesthesiologist and respiratory therapist skilled in noninvasive positive pressure ventilation (NPPV) should be present 1

Respiratory Support Strategy

• Patients with FVC <50% predicted require assisted ventilation during induction, maintenance, and recovery 1
• Patients with FVC <30% predicted are at high risk and strongly require ventilatory support throughout 1
• Consider extubation directly to NPPV for patients with baseline FVC <50% predicted 1
• Multiple respiratory support options available: endotracheal intubation, laryngeal mask airway, or face mask with bilevel positive pressure ventilation 1

Critical Preoperative Assessment

Pulmonary Evaluation

• Measure FVC, maximum inspiratory pressure (MIP), maximum expiratory pressure (MEP), and peak cough flow (PCF) 1
• Measure SpO₂ in room air; if ≤95%, obtain blood or end-tidal CO₂ levels 1
• For patients at high risk (PCF <270 L/min or MEP <60 cm H₂O), provide preoperative training in mechanically assisted cough 1

Cardiac Assessment

• Mandatory cardiology consultation before any anesthetic as DMD causes dilated cardiomyopathy 1
• Normal preoperative ECG and echocardiogram do not exclude postoperative cardiac complications 1
• Intravascular fluid shifts can precipitate congestive heart failure 1

Nutritional and Metabolic Optimization

• Assess serum albumin and prealbumin to identify poor healing risk 1
• Optimize nutritional status preoperatively as malnutrition profoundly affects respiratory muscle strength 1
• Evaluate and manage dysphagia to prevent postoperative nutritional complications 1

Postoperative Management

Immediate Recovery Period

• Continuous SpO₂ monitoring for minimum 24 hours postoperatively 8
• Use supplemental oxygen cautiously as excessive oxygen masks hypoventilation 8
• Continue NPPV postoperatively for patients with baseline FVC <50% predicted 1
• Admit to ICU or high-dependency unit for continuous monitoring 8

Common Pitfalls to Avoid

• Never assume brief procedures are low-risk - even short anesthetics carry significant complications in DMD 1
• Do not transport unstable patients from operating room to ICU; consider extubating in ICU setting for high-risk patients 1
• Delayed respiratory insufficiency can occur hours after apparently successful extubation, requiring extended monitoring 3
• Cardiac arrest may occur despite adequate respiratory support if metabolic derangements develop 3

Special Considerations for Polymyositis

While the evidence focuses primarily on DMD, the coexistence of polymyositis adds inflammatory muscle disease to the dystrophic process, potentially increasing anesthetic sensitivity. The same principles apply with even greater vigilance regarding:

• Avoiding all depolarizing muscle relaxants 1
• Using minimal doses of non-depolarizing agents if absolutely required 2
• Maintaining aggressive respiratory support throughout the perioperative period 1