What are the anesthetic implications for patients with COL6A+ (Collagen Type VI Alpha) Bethlem/Ullrich Myopathy?

Anesthetic Management of COL6A+ Bethlem/Ullrich Myopathy

Critical First Principle

Patients with COL6A+ Bethlem/Ullrich myopathy require trigger-free anesthesia with absolute avoidance of succinylcholine and cautious use of non-depolarizing muscle relaxants, combined with meticulous respiratory monitoring due to progressive restrictive lung disease and potential cardiac involvement. 1, 2

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Preoperative Assessment

Respiratory Evaluation

• Obtain baseline pulmonary function tests including FVC, MEP, and peak cough flow (PCF) to quantify respiratory muscle weakness, as these patients develop progressive restrictive lung disease that may not manifest until adulthood 1, 2
• Patients with FVC <50% of predicted require heightened vigilance and planning for postoperative ventilatory support 3
• Measure baseline train-of-four (TOF) ratio before any muscle relaxant administration—if TOF <0.9 at baseline, sensitivity to non-depolarizing agents is significantly greater 4

Cardiac Assessment

• Mandatory cardiology consultation with echocardiography and ECG to detect right-sided heart disease, pulmonary hypertension, or conduction abnormalities secondary to chronic restrictive lung disease 3, 1, 2
• These cardiovascular complications can develop silently as the myopathy progresses 1

Airway Evaluation

• Assess for high-arched palate and fixed flexion deformities of the cervical spine/temporomandibular joint that may predict difficult intubation 1, 2
• Prepare difficult airway equipment in advance 1

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Intraoperative Management

Anesthetic Technique Selection

Regional anesthesia (spinal, epidural, peripheral nerve blocks) or local anesthesia is the preferred approach when surgically feasible, completely avoiding risks associated with general anesthesia and muscle relaxants 3, 4

If general anesthesia is required:

Muscle Relaxant Management

Succinylcholine is absolutely contraindicated due to risk of hyperkalemic cardiac arrest and rhabdomyolysis in all myopathic patients 3, 5, 2

For non-depolarizing muscle relaxants:

• Use rocuronium, atracurium, or cisatracurium at 50-75% of standard doses due to increased sensitivity and prolonged duration of action 4, 2
• Avoid atracurium and mivacurium if possible due to histamine release that may trigger hemodynamic instability 5
• Quantitative neuromuscular monitoring with TOF is mandatory throughout the case 4, 2

Anesthetic Agent Selection

Total intravenous anesthesia (TIVA) with propofol and remifentanil is the safest approach for most myopathies to avoid anesthesia-associated rhabdomyolysis 5, 2

• Propofol is preferred for induction due to short duration allowing rapid respiratory assessment 4
• Volatile anesthetics (sevoflurane, isoflurane) may be used cautiously in non-MH-linked myopathies, though TIVA remains safer 4, 2
• Prepare anesthesia workstation as trigger-free: remove vaporizers, change breathing circuit, flush with oxygen at maximum flow, or use activated charcoal filters 3

Intraoperative Monitoring

• Five-lead ECG with continuous ST-segment monitoring 3
• Invasive arterial blood pressure monitoring if cardiac disease is advanced 3
• Continuous core temperature monitoring to detect malignant hyperthermia, though COL6A+ myopathies are not clearly associated with MH 3, 2
• Quantitative neuromuscular monitoring (TOF) if any muscle relaxant is used 4, 2

Positioning Precautions

Extreme care in patient positioning is essential due to joint contractures and connective tissue abnormalities that increase risk of pressure injuries and joint dislocations 1, 2

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Postoperative Management

Reversal Strategy

Sugammadex is the preferred reversal agent for rocuronium-induced neuromuscular blockade, not neostigmine, due to rapid and predictable reversal 4, 1

Extubation Criteria

• Ensure TOF ratio >0.9 before extubation to confirm complete reversal of neuromuscular blockade 3, 4
• Delay extubation until respiratory secretions are well controlled and SpO2 is normal or baseline in room air 3
• For patients with FVC <50% predicted, consider extubating directly to noninvasive positive pressure ventilation (NPPV) 3

Respiratory Support

• Use supplemental oxygen cautiously—monitor SpO2 continuously and assess if hypoxemia is due to hypoventilation, atelectasis, or airway secretions 3
• Monitor blood or end-tidal CO2 levels whenever possible 3
• Use manually assisted cough and mechanical insufflation-exsufflation (MI-E) postoperatively in patients with impaired cough (PCF <270 L/min or MEP <60 cm H2O) 3

Monitoring Duration

Admit to ICU or high-dependency unit for continuous cardiopulmonary monitoring for at least 24-48 hours, even after seemingly uncomplicated procedures, due to respiratory sensitivity and potential cardiac complications 5, 1, 2

Pain Management

• Prioritize non-opioid analgesics (acetaminophen, NSAIDs) 5
• If opioids are required, use reduced doses with extended monitoring due to increased sensitivity to respiratory depression 3, 5
• Avoid morphine due to histamine release 5

Gastrointestinal Management

• Initiate bowel regimens to prevent constipation 3
• Consider gastric decompression with nasogastric tube if GI dysmotility is present 3

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Critical Pitfalls to Avoid

• Never discharge to regular ward settings—these patients require extended monitoring even after routine procedures 5, 1, 2
• Never use succinylcholine under any circumstances 3, 5, 2
• Never assume normal respiratory function based on clinical appearance—progressive restrictive lung disease may not be clinically apparent until advanced 1, 2
• Never rely on clinical assessment alone for neuromuscular blockade reversal—quantitative TOF monitoring is mandatory 4, 2
• Avoid aminoglycosides and fluoroquinolones perioperatively as they worsen neuromuscular transmission 4