What is the recommended management for diaphragmatic spasm?

Management of Diaphragmatic Spasm

The immediate management of diaphragmatic spasm depends on the clinical context: in perioperative laryngospasm (often confused with diaphragmatic spasm), administer propofol 1-2 mg/kg IV followed by suxamethonium 1 mg/kg IV if hypoxia persists; for chronic diaphragmatic spasm presenting with chest pain and dyspnea, small doses of IV sodium amytal can abort acute attacks, while carbamazepine 200-400 mg three times daily is effective for high-frequency diaphragmatic flutter. 1, 2, 3

Acute Management Algorithm

Perioperative Setting (Laryngospasm/Airway Obstruction)

The evidence primarily addresses laryngospasm rather than true diaphragmatic spasm, but the management principles overlap when dealing with respiratory muscle spasm in the perioperative period:

Step 1: Initial Measures

• Call for help immediately 1
• Apply continuous positive airway pressure with 100% oxygen using reservoir bag and facemask while ensuring upper airway patency 1
• Avoid unnecessary upper airway stimulation 1

Step 2: Larson's Manoeuvre

• Place middle finger of each hand in the 'laryngospasm notch' between posterior border of mandible and mastoid process 1
• Simultaneously displace mandible forward in jaw thrust 1
• Apply deep pressure at this point to help relieve spasm 1

Step 3: Pharmacologic Intervention if Spasm Persists

• Propofol 1-2 mg/kg IV: Low doses may be effective in early spasm, but larger doses are needed for severe or total closure 1
• This is effective in 77% of cases 4

Step 4: Muscle Relaxant if Hypoxia Worsens

• Suxamethonium 1 mg/kg IV for worsening hypoxia with continuing severe spasm 1
• Alternative routes if no IV access: intramuscular (2-4 mg/kg), intralingual (2-4 mg/kg), or intra-osseous (1 mg/kg) 1
• Atropine may be required to treat bradycardia, especially in children under 3 years (0.02 mg/kg) 1, 4

Step 5: Surgical Airway in Extremis

• Consider if all other measures fail 1

Non-Operative Diaphragmatic Spasm

Acute Attack Management:

• Small IV injection of sodium amytal can promptly interrupt attacks 2
• Conscious effort at full expiration can abort some episodes 2
• These patients present with chest pain, dyspnea, and inability to get a full breath, with fluoroscopy showing nearly maximally contracted (flat) diaphragm 2

Chronic High-Frequency Diaphragmatic Flutter:

• Carbamazepine 200-400 mg three times daily leads to disappearance or great improvement of flutter and clinical symptoms 3
• This is indicated for patients with repetitive diaphragmatic discharges of 9-15 Hz on EMG 3
• Symptoms include esophageal belching, hiccups, and retching 3

Alternative for Post-Cardiac Surgery Cases:

• Gabapentin has been reported successful in treating severe diaphragmatic spasm after cardiac surgery causing respiratory functional impairment 5

Prevention Strategies (Perioperative Context)

Timing of Extubation:

• Avoid extubation during lighter planes of anesthesia, as this is when risk is greatest 1
• Perform suction under direct vision with patient deeply anesthetized 1
• Avoid further stimulation until patient is awake 1

Pharmacologic Prevention:

• Topical lidocaine sprayed onto vocal cords at induction reduces risk of laryngospasm following short procedures 1
• Choice of anesthetic agent matters: sevoflurane and propofol are least irritant 1
• Other adjuncts include IV lidocaine, doxapram, magnesium, and ketamine 1

Critical Pitfalls to Avoid

Do not delay muscle relaxant administration when hypoxia is worsening—suxamethonium is fast-acting and laryngeal muscles are particularly sensitive to it 4

Be aware of post-obstructive pulmonary edema: Forceful inspiratory efforts against obstructed airway can lead to non-cardiogenic pulmonary edema, occurring in 0.1% of general anesthetics, more common in young muscular adults (male:female ratio 4:1) 1

Ensure immediate availability of suxamethonium and atropine in operating theaters, especially pediatric settings, as this reduces incidence of cardiac arrest and severe airway obstruction accidents by nearly half 4

Recognize that complete obstruction presents with silent inspiration, not the characteristic "crowing" sound of partial obstruction 1

Consider alternative diagnoses: In pediatric settings with ketamine use, laryngospasm may occur most often with rapid infusion or concomitant upper respiratory infection, usually reversible with oxygen, airway repositioning, and brief positive-pressure ventilation 6