Laryngospasm

Description

Laryngospasm is a protective reflex closure of the glottis as a result of abnormal stimulus (1)[B].
Perioperatively this can result in airway obstruction with resultant desaturation.

Epidemiology

Incidence

The overall incidence of laryngospasm is 0.87% (2)[C].
The incidence ranges from 1.74% in children aged 9 years old to 2.82% in infants (2)[C].

Prevalence

Increased in children
More frequent during emergence from anesthesia
Tonsillectomies and adenoidectomies have the highest incidence of post-extubation laryngospasm.

Morbidity

Oxygen desaturation
Anoxic brain injury
Negative pressure pulmonary edema
Bradycardia
Pulmonary aspiration
Cardiac arrest

Mortality

Although laryngospasm has been quoted as a preceding cause of airway obstruction and ultimately death, the exact incidence of mortality is unknown.

Etiology/Risk Factors

Insufficient depth of anesthesia
Young age
Airway irritation (blood/secretions, regurgitation)
Airway manipulation
Upper respiratory tract infections
Smokers
Passive smoke exposure
Type of surgery (e.g., tonsillectomy and adenoidectomy)

Physiology/Pathophysiology

Afferent fibers of the superior laryngeal nerve control laryngeal muscle contractions which protect the airway during swallowing.
Laryngospasm occurs when there is loss of inhibition of the laryngeal closure reflex as a result of abnormal excitation (3)[A]. This commonly occurs during induction and upon emergence from anesthesia. The patient is particularly vulnerable during the second stage of anesthesia. The presence of saliva, mucus secretions, and airway devices (endotracheal tube, trumpets) can elicit abnormal excitation and can lead to laryngospasm.
It is important to note that laryngospasm is mediated by skeletal muscle while bronchospasm is smooth muscle mediated.
Laryngospasm is characterized by the prolonged interruption of respiration due to a ball valve mechanism of the vocal cords, false cords, and supraglottic tissue.

Prevantative Measures

Topical lidocaine can blunt the airway response to irritation and instrumentation.
If mask induction is performed, sevoflurane or halothane should be used as these 2 agents are the least irritating to the airway.
Desflurane is very irritating to the unprotected airway and should be avoided during mask inductions.
If IV line insertion is performed after a mask induction, it should be done after deep anesthesia has been achieved.
The use of an adequate dose of muscle relaxants will minimize the chances of laryngospasm during intubation. An appropriate amount of time should be allowed for full onset.
Suctioning of the oropharynx before emergence (stage 2) from anesthesia
Antisialagogues (to reduce secretions) may be considered.
Avoid painful stimulation during emergence.

Diagnosis ⬆ ⬇

Laryngospasm can be characterized as partial or complete.
Partial laryngospasm is generally associated with an audible inspiratory or expiratory sound of airway obstruction.
As the obstruction becomes worse, tracheal tug and paradoxical respiratory movements of the chest and abdomen will develop.
Should laryngospasm progress from partial to complete, the audible signs cease, leaving only visible signs of airway obstruction.
Oxyhemoglobin desaturation, cyanosis, bradycardia, and subsequently cardiac arrest may follow if the symptoms are not treated promptly.

Differential Diagnosis

Supraglottic obstruction: This is usually relieved by performing a jaw thrust, chin lift, and insertion of an oropharyngeal airway (2)[C].
Bronchospasm: This is characterized by wheezing on auscultation and diminished breath sounds (2)[C].

Treatment ⬆ ⬇

Partial laryngospasm
- CPAP with 100% oxygen and a tight-fitting mask can help facilitate ventilation and/or deepen the level of anesthesia
Complete laryngospasm
- CPAP will not break complete laryngospasm because forced inflation of the pharynx distends the piriform fossa on either side of the larynx and presses the aryepiglottic folds more firmly against each other. Oxygen will fill the stomach instead of the lungs.
- In the absence of an IV line, perform continuous positive airway pressure (CPAP) with 100% oxygen, optimize airway with a jaw thrust and chin lift, and deepen anesthesia with an inhalational agent (preferably sevoflurane or halothane). If these measures fail, administer succinylcholine 4 mg/kg intramuscularly.
- In addition to IV propofol, airway optimization should be performed. This should be done by performing a jaw thrust and chin lift maneuver. This will stretch the geniohyoid muscle to partially open the larynx and allow for ventilation and further deepening of anesthesia with inhalational agents.
- If the above measures fail a muscle relaxant may be given to relax the vocal cords. Succinylcholine 0.1 mg/kg allows for quick onset and recovery.
- Emergence even after treatment with succinylcholine. It is therefore important to eliminate contributing noxious stimuli before attempting another emergence.
- In the presence of an IV line, complete laryngospasm should be treated by deepening anesthesia with propofol (0.25–0.8 mg/kg) (1)[B].

Pediatric Considerations

Succinylcholine administration in children may be associated with severe bradycardia and cardiac arrest; thus, it is highly recommended to give atropine (0.02 mg/kg) with succinylcholine.

Gentle chest compression with 100% oxygen in children. 3 theories for efficacy:

Vocal cord spasm prevents entrance of air into the lung, but not its exit; thus, chest compression "pushes" air in the lung directly on the vocal cords to relieve the spasm. It functions to deliver positive pressure, but from the "opposite" direction of CPAP.
Second, chest compression stimulates fast, shallow breathing with or without increases in minute ventilation. This results in an increased respiratory drive.
Third, the Hering–Breuer deflation reflex mediated via the vagus nerve is activated by stimulation of stretch receptors or stimulation of proprioceptors activated by lung deflation. Thus, vocal cord relaxation may result from vagal nerve impulses.
Benefits over CPAP include not distending the stomach or splinting of the diaphragm (4)[A].

Magnesium: Doses of 15 mg/kg over 20 minutes appeared to significantly decrease the incidence of laryngospasm in pediatric patients (5).

Follow-Up ⬆ ⬇

Patients without immediate, apparent complications should be observed for 2–3 hours and then discharged.
Negative pressure pulmonary edema can occur after laryngospasm. This is the result of decreased intrathoracic pressure generated by an attempted inspiration against a closed glottis. This creates a mean negative transpulmonary pressure, leading to transudation of fluid from the pulmonary capillaries into the interstitial space.
- The clinical signs are oxygen desaturation, pink frothy sputum in the airway, or signs of alveolar infiltration on CXR.
- Treatment is directed at supplementation of oxygen and diuretics. Occasionally, patients may require reintubation to facilitate adequate oxygenation.
Patients who develop cardiopulmonary complications including negative pressure pulmonary edema should be admitted for further care.

Closed Claims Data

A review of the malpractice database from 1973 to 2000 revealed that airway obstruction including laryngospasm (n = 8) was the most common respiratory event.
Another review of the Pediatric Perioperative Cardiac Arrest Registry from 1998 to 2004 determined that causes accounted for 27% of all cardiac arrest episodes and that airway obstruction from laryngospasm was the most common cause (6%).

References ⬆ ⬇

Al-alami AA , Zestos MM , Baraka AS. Pediatric laryngospasm: Prevention and treatment. Curr Opin Anaesthesiol. 2009;22(3):388–395.
Alalami AA , Ayoub CM , Baraka AS. Laryngospasm: Review of different prevention and treatment modalities. Paediatr Anaesth. 2008;18(4):281–288.
Burgoyne LL , Anghelescu DL. Intervention steps for treating laryngospasm in pediatric patients. Paediatr Anaesth. 2008;18(4):297–302.
Al-Metwalli RR , Mowafi HA , Ismail SA. Gentle chest compression relieves extubation laryngospasm in children. J Anesth. 2010;24:854–857.
Gulhas N , Durmus M , Demirbilek S , et al. The use of magnesium to prevent laryngospasm after tonsillectomy and adenoidectomy: A preliminary study. Paediatr Anaesth. 2003;13(1):43–47.

section name header

Basics ⬇

Incidence

Prevalence

Morbidity

Mortality

Diagnosis ⬆ ⬇

Treatment ⬆ ⬇

Pediatric Considerations

Follow-Up ⬆ ⬇

References ⬆ ⬇

Additional Reading ⬆ ⬇

Codes ⬆ ⬇

Clinical Pearls ⬆ ⬇

Author(s) ⬆