2008april/20080422.ppt" classpediatric laryngospasm

Pediatric laryngospasm

R4: 曾揚旗

Pediatric laryngospasm

Laryngospasm: review of different prevention and treatment modalities

Pediatric Anesthesia 2008 18: 281–288

Pediatric laryngospasm Pediatric Anesthesia 2008 18: 303–307

Risk factors for laryngospasm in children during general anesthesia

Pediatric Anesthesia 2008 18: 289-296

Introduction

Laryngospasm is mainly seen in children.

A reflex closure of the upper airway as a result of the glottic musculature spasm prevent foreign material entering the tracheobronchial tree.

This leads to hypoxia and hypercapnea.

Introduction

Prolong hypoxia and hypercapnea abolishes the spastic reflex and the problem is self-limited.

Cardiac arrest, arrhythmia, pulmonary edema, bronchospasm or gastric aspiration may occur.

Definition

Laryngospasm can be defined as glottic closure due to reflex constriction of the laryngeal muscles.

Complete laryngospasm – chest movement but silent with no bag movement and no ventilation possible.

Partial laryngospasm – chest movement but stridulous noise with a mismatch between the patients’ respiratory effort and the small amount of bag movement.

Epidemiology

The overall incidence of laryngospasm is 0.87%.

The incidence in children in the first 9 years of age is 1.74%.

A higher incidence of 2.82% in infants between 1 and 3 months

Mechanism

Most laryngeal reflexes are elicited by stimulation of the afferent fibers contained in the internal branch of the superior laryngeal nerve.

These reflexes control the laryngeal muscle contractions which protect the airway during swallowing.

Clinical manifestation

Signs in both partial and complete laryngospasm : airway obstruction (tracheal tug, paradoxical movement of the chest and abdomen).

Late signs: oxyhemoglobin desaturation, bradycardia and central cyanosis.

Differential diagnosis

Complete laryngospasm Partial laryngospasm Supraglottic obstruction Psychogenic laryngospasm

Risk factors

Anesthesia-related factorsPatient-related factorsSurgery-related factors

Anesthesia-related factors

During anesthesia and emergence: (1) including tracheal intubation, (2) laryngospasm tends to occur after extub

ation (3) spontaneous breathing using a face or la

ryngeal mask.

Anesthesia-related factors

Intravenous (i.v.) induction agents induce laryngospasm

Incidence : Barbiturates (thiopentone) > Ketamine > Propofol

Anesthesia-related factors

Volatile anesthetics Incidence : desflurane > Isoflurane > se

vofluraneLaryngospasm occur in children which

are supervised by less experienced anesthesiologists

Patient-related factors

Incidence of laryngospasm following GA is inversely correlated with age.

Upper respiratory tract infection and airway anomaly (10-fold more prone to develop laryngospasm).

‘passive smoking”, gastroesophageal reflux, patients with elongated uvula and those with history of choking during sleep

Surgery-related factors

Tonsillectomy and adenoidectomy have the highest incidence of laryngospasm (21–26%).

Appendicectomy, cervical dilation, hypospadias surgery, skin transplant and esophageal procedures.

Surgery-related factors

Prevention

Anesthesia induction

Identify the risk factor

Premedication with anticholinergics and benzodiazepine

Insert IV line 2 min after sevoflurance induction ( loss of lid reflex)

Tracheal intubation after ensuring adequate level of anesthesia

PreventionPreventionEmergence

Gentle suctioning of the blood and sections

Put the patient on lateral position

Discontinue inhalation anesthetics

Give lidocaine 1mg/kg iv or propofol 0.25-0.5 mg/kg iv

Wait for the patient to open the eyes and spontaneuosly wake up

Extubate the trachea using the “artificial cough” technique

PreventionPreventionEmergence

Gentle suctioning of the blood and sections

Premedication with anticholinergics and benzodiazepine

Discontinue inhalation anesthetics

Give lidocaine 1mg/kg iv or propofol 0.25-0.5 mg/kg iv

Wait for the patient to open the eyes and spontaneuosly wake up

Extubate the trachea using the “artificial cough” technique

TreatmentIdentification and removal of the offending stimulus such as secretion,

mucus or blood

Inserting an oral or nasal airway if possible

Apply jaw thrust maneuver while firmly pressing on the “laryngospasm notch”

Intermitent positive pressure ventilation with face mask

If laryngospasm is not relieved, deepen the lavel of anesthesia by propofol iv 0.25-0.8 mg/kg

If laryngospasm is not relieved, inject suxamethonium iv 0.1-3 mg/kg or im 3-4 mg/kg followed by mask ventilation and /or tracheal intubation

Treatment

Identification and removal of the offending stimulus such as secretion, mucus or blood

Inserting an oral or nasal airway if possible

Apply jaw thrust maneuver while firmly pressing on the “laryngospasm notch”

Intermitent positive pressure ventilation with face mask

If laryngospasm is not relieved, deepen the lavel of anesthesia by propofol iv 0.25-0.8 mg/kg

If laryngospasm is not relieved, inject suxamethonium iv 0.1-3 mg/kg or im 3-4 mg/kg followed by mask ventilation and /or tracheal intubation

Treatment

The question of whether to use propofol or suxamethonium is a matter of timing.

Propofol should be used prior to suxamethonium.

It is successful in treating laryngospasm in 76.9% of cases and free of cardiovascular events.

Treatment

First, is the lack of interaction of a depolarizing drug with a previously administered nondepolarizing muscle relaxant.

Second, avoiding suxamethonium will eliminate the possibility of prolonged paralysis in patients with pseudocholinesterase deficiency.

Finally, propofol can be used when suxamethonium is contraindicated

Treatment

Suxamethonium still has a crucial role when propofol is unsuccessful.

Its administration should not be delayed until the patient becomes severely desaturated (SpO2 < 85%) severe bradycardia and even cardiac arrest.

It is highly recommended to give atropine at 0.02 mg/kg) i.v. prior to administration of suxamethonium to treat laryngospasm

Treatment

Chung and Rowbottom showed that the use of 0.1 mgAkg)1 i.v. of suxamethonium was successful in treating laryngospasm

Maintenance of spontaneous breathing thus avoiding further hypoxia and the avoidance of bradycardia.

Treatment

When laryngospasm occurs during inhalational induction without previous i.v. access several options can be used.

Warner recommends that i.m. suxamethonium can be administered at 4 mg/kg) followed by tracheal intubation

Treatment

Donati et al. Advise against the use of i.m. suxamethonium for intubation without i.v. access.

They suggest establishing an i.v. access for the administration of drugs to treat laryngospasm

Weiss et al. recommend using the I.O. route as an efficient and quick access to give neuromuscular blocking drugs with faster central circulation times.

Conclusions