⚠️ When Silence Strikes: Stepwise Management and Prevention of Perioperative Laryngospasm🤔

2025年11月6日

👉👉　🇺🇸 All Posts 🇬🇧 / 🇯🇵 記事一覧 🇯🇵　👈👈

Contents

♦️ Introduction

🚨 Why this matters:

Laryngospasm can escalate from stridor to cardiac arrest within minutes, with an incidence of 0.8–5% in general anesthesia (≈0.9% in elective pediatric cases).
Complications include bradycardia, negative-pressure pulmonary edema (NPPE), aspiration, and rare cardiac arrest. Early recognition and a standardized algorithm are critical for safe resolution.

💡 What you’ll gain:

Pathophysiology primer, actionable risk-factor assessment, a four-step management algorithm (maneuvers → CPAP → deepen anesthesia → neuromuscular blockade ± intubation), prevention tactics, and simulation-proven strategies that improve both technical and non-technical performance.

♦️ Definition and Pathophysiology

🔷 What is laryngospasm?

Laryngospasm is a sustained, reflexive adduction of the vocal cords that partially or completely blocks airflow. It begins as a protective response to supraglottic irritation (e.g., secretions, blood, suction) but can persist after the stimulus and cause life-threatening obstruction.
Afferents arise from the internal branch of the superior laryngeal nerve, with efferent activation of intrinsic laryngeal adductors via the recurrent laryngeal nerve. Autonomic co-activation (vagal) explains associated bradycardia and hemodynamic changes.

🔷 Clinical presentations:

Partial closure: inspiratory stridor, paradoxical breathing, falling SpO₂
Complete closure: “silent chest,” no bag movement, absent capnogram, precipitous desaturation

🎓 Exam Focus:
Neural pathway = superior laryngeal (afferent) → NTS → recurrent laryngeal (efferent).

♦️ Epidemiology and Risk Factors

📊 Incidence and timing

Ranges 0.8–5% overall; ≈0.9% pediatric elective. Peaks occur at induction and emergence (esp. extubation).

🔍 Patient-related risks

Age <1 yr, recent URI, asthma, smoking, OSA, GERD, obesity.

🔧 Surgical/anesthetic risks

Upper airway surgery (tonsillectomy/adenoidectomy), bronchoscopy, GI endoscopy; light anesthesia; desflurane or irritants; suction; extubation during light plane.

🏥 Clinical Pearl:

UK APRICOT sub-analysis shows lower severe respiratory event rates in centers with pediatric anesthesia expertise—supporting structured care pathways.

Section 3. Clinical Presentation and Diagnosis

🔍 Early signs:

Inspiratory stridor
suprasternal retraction
paradoxical breathing
desaturation

❗ Complete obstruction:

No capnogram
no bag movement
exaggerated effort without ventilation.

⚠️ Complications:

Bradycardia (~6%)
NPPE (~4%)
aspiration (~3%)
cardiac arrest (~0.5%)

🎓 Exam Focus:
Differentiate from bronchospasm (wheezing, capnogram present) and supraglottic obstruction (changes with position).

♦️ Stepwise Management Algorithm

✅ Step 1 — Remove stimulus & basic maneuvers

Stop stimulation
Jaw thrust, head extension; ensure tight mask
Deliver 100% O₂ with CPAP
Consider oropharyngeal airway
Optional: bilateral Larson’s maneuver (digital pressure behind ear lobule)

🏥 Pearl: Jaw thrust + CPAP + stop stimulus often breaks partial spasm.

✅ Step 2 — Deepen anesthesia

Propofol 0.25–0.8 mg/kg IV is first-line to suppress reflexes. Continue gentle PPV.

🎓 Exam: Propofol is first-line for reflex laryngospasm due to light anesthesia.

✅ Step 3 — Neuromuscular blockade

Succinylcholine 0.1 mg/kg IV (range 0.1–0.5)
Alternative: rocuronium if succinylcholine contraindicated
Caution: MH, hyperkalemia, neuromuscular disorders, major burns, prolonged immobility

🏥 Pearl: Always prepare for PPV/intubation after relaxant.

✅ Step 4 — Advanced airway

If unresolved: intubate under direct laryngoscopy.
If can’t intubate/can’t oxygenate → front-of-neck access per institutional CICO protocol.

📋 Post-resolution monitoring:

Observe 2–3 h in PACU for NPPE. Reassess lungs, gas exchange, diuresis/PEEP if needed.

♦️ Prevention Strategies

💊 Pharmacologic

IV lidocaine 1–2 mg/kg ~2 min pre-extubation (blunts reflexes)
Magnesium 15 mg/kg IV intraop or near extubation reduces cough
Propofol induction preferred in airway hyperreactivity

🛠️ Technique and timing

Clear secretions/blood meticulously
Extubate deep or fully awake, avoid light plane
Extubation with lung inflation may reduce adductor excitability

🏥 Pearl:
After URI, reactivity persists weeks → postpone or minimize irritation (LMA, experienced provider, propofol induction, careful suction).

♦️ Simulation & Evidence

📚 Simulation trials confirm algorithm benefit: improved technical (median 8.5 vs 5, p<0.0001) and ANTS scores (BMJ Stel 2019).

🎓 Exam:
Sequence = stop stimulus → jaw thrust + CPAP → propofol → muscle relaxant → intubate → PACU surveillance.

Frequently Asked Questions

Q1: What is the first-line treatment for suspected laryngospasm?

A: Stop the stimulus, apply jaw thrust, deliver 100% O₂ with CPAP, and ensure mask/airway adjuncts are correct. If not resolving, deepen anesthesia with propofol (0.25–0.8 mg/kg IV) before proceeding to neuromuscular blockade.

Q2: When should I give a muscle relaxant?

A: If jaw thrust + CPAP + propofol fail or the patient is rapidly desaturating, give succinylcholine 0.1 mg/kg IV (or rocuronium if succinylcholine is contraindicated) and prepare for intubation.

Q3: Which patients are highest risk?

A: Infants (<1 yr), recent URI, asthma, smokers, OSA/GERD, and those undergoing upper airway surgery or managed in a light anesthetic plane.

Q4: How do I prevent laryngospasm at extubation?

A: Suction thoroughly, consider IV lidocaine 1–2 mg/kg or MgSO₄ 15 mg/kg, and extubate deep or fully awake with a no-touch approach—not in between.

Q5: Does simulation or algorithm training really help?

A: Yes. A randomized study showed better technical and ANTS scores with a simple algorithm (median 8.5 vs 5, p<0.0001), advocating for cognitive aids and regular simulation.

♦️ Summary

Laryngospasm is a time-critical airway emergency. Incidence ≈ 0.8 – 5 % overall (≈ 0.9 % pediatric elective), peaking at induction and emergence.
Risk factors include age < 1 yr, recent URI, asthma, smoking, OSA/GERD, and airway irritation in light anesthesia.
Prevent by controlling depth, clearing secretions, and considering lidocaine 1–2 mg/kg IV, MgSO₄ 15 mg/kg, and propofol induction.

When laryngospasm occurs:

1️⃣ Stop stimulus → jaw thrust + CPAP with 100 % O₂
2️⃣ Deepen with propofol 0.25 – 0.8 mg/kg IV
3️⃣ Give succinylcholine 0.1 mg/kg IV (or rocuronium)
4️⃣ Intubate if needed → PACU observe 2–3 h for NPPE

Simulation data and system-level analyses (APRICOT UK) confirm that algorithmic training and experienced teams reduce critical events.
Embed this algorithm in your airway SOP and rehearse it regularly—because when silence strikes, seconds matter.

📝 Take Home Massages

🔑 Key Points

🧠 Recognize fast: stridor → paradoxical breathing → silent chest = complete closure
✅ Act early: Stop stimulus, jaw thrust, CPAP, 100 % O₂
💊 Deepen promptly: Propofol 0.25 – 0.8 mg/kg IV
🧷 Commit decisively: Succinylcholine 0.1 mg/kg IV (or rocuronium) then intubate
🧽 Prevent smartly: clear secretions, lidocaine 1–2 mg/kg IV, MgSO₄ 15 mg/kg, extubate deep or awake (no “in-between”)
🏥 Aftercare: Observe 2–3 h for NPPE and debrief the team