Laryngospasm

Take home messages

• Laryngospasm is common, preventable and treatable
• It's also potentially life-threatening
• Leave the airway alone during emergence

What is it?

Our favourite guardians of the glottis - the vocal cords - hold the keys to the most sensitive reflex of the human body, the cough reflex.

It is not hard to see how this evolved to become so effective, as it is the most immediately life-saving function the body has.

When tickled, touched or troubled, the tetchy twosome trigger and slam shut to protect the trachea and respiratory tree below, which is of mixed benefit depending on the situation.

• Piece of food attempting to go cave diving - good
• Anaesthetist trying to remove ET tube - bad

Unsurprisingly, laryngospasm is most frequently encountered during airway manipulation, usually extubation, when the patient is spending a longer period of time in a shallower plane of anaesthesia.

What does it look like?

The patient is trying to breathe with a closed glottis, and depending on how closed, the signs and symptoms may include:

• Stridor (or silence)
• See-saw breathing
• Suprasternal, intercostal and subcostal recession
• Hypoxia
• Cyanosis
• Increasing distress
• Loss of ETCO2 trace
• High ventilatory pressures (if using a supraglottic airway)

Clearly if you've got the above with a well-sited endotracheal tube, it's time to start thinking of other diagnoses.

What can we do about it?

Radical Cancellectomy

The look of disappointment on the parent's face as you tell them on the morning of the operation that their starved child's tonsillectomy is going to be delayed again for at least four weeks - just because they had a bit of a cold - is never easy to bear.

But they generally understand when you explain that a child with a recent upper respiratory tract infection, for a tonsillectomy, is over ten times more likely to have problems such as laryngospasm, and are equally keen to avoid that unnecessary risk for an elective procedure, however frustrating it may be.

Larson's Manoeuvre

Larson's manoeuvre is awesome - it has helped me out several times.

You stick your fingers behind angle of the jaw and in front of the mastoid process (over the styloid process) and push hard.

Like a stubborn jam jar, the vocal cords usually pop right open.

Here's Larson's original paper

Laryngospasm-The Best Treatment

Professor Emeritus; Anaesthesia and Neurosurgery; Stanford University; Professor of Clinical Anesthesiology; UCLA School of Medicine;plarson@ucla.eduTo the Editor:-When considering the treatment of laryngospasm, standard textbooks of anesthesiology suggest virtually the same sequence: namely jaw thrust at the angle of the mandible while applying positive-pressure ventillation with oxygen, 100%, by bag and mask and, if that fails, administering succinylcholine, the recommended dose varying from 0.25 to 1 mg/kg intravenously or 4 mg/kg intramuscularly. [1-8]In addition, some texts recommend suctioning foreign material from the oropharynx, administering lidocaine, 1 to 1.5 mg/kg, and removing or avoiding any painful stimulus. One author recommended digital elevation of the tongue by inserting an index finger deep into the pharynx, a treatment of substantial risk to the therapist. [9]Almost 40 years ago, Dr. N. P. Guadagni showed me a technique for prompt termination of laryngospasm, which I have used countless times with complete success. Because I have used the techniques so often myself and have taught it to hundreds of residents and nurses, I presumed that it was common knowledge and well documented in the literature. However, a thorough literature search has not revealed any mention of it. The technique involves placing the middle finger of each hand in what I term the laryngospasm notch. This notch is behind the lobule of the pinna of each ear. It is bounded anteriorly by the ascending ramus of the mandible adjacent to the condyle, posteriorly by the mastoid process of the temporal bone, and cephalad by the base of the skull (Figure 1). The therapist presses very firmly inward toward the base of the skull with both fingers, while at the same time lifting the mandible at a right angle to the plane of the body (i.e., forward displacement of the mandible or “jaw thrust”). Properly performed, it will convert laryngospasm within one or two breaths to laryngeal stridor and in another few breaths to unobstructed respirations.The most common mistake made by those learning the technique is to place the fingers lower on the ramus of the mandible or at the angle of the jaw. Pressure and forward displacement of the mandible at these locations will elevate the tongue from the posterior pharyngeal wall but will not correct laryngospasm. To be effective for laryngospasm, the pressure must be firm and must be applied at the most cephalad portion of the laryngospasm notch. It is desirable to administer oxygen while performing the technique. This is easily performed by holding a mask over the patient’s face with the thumb and index fingers of each hand while using the middle fingers for applying pressure and forward displacement. The technique is effective in infants, children, and adults. Because the patient is making respiratory efforts at the time of treatment, there is no need to apply positive pressure on the reservoir bag of the anesthetic machine, although an assistant can do so if the anesthesiologist wishes. I believe this technique for treatment of laryngospasm is far superior to those recommended herein because it is absolutely reliable, it resolves the spasm more rapidly than positive pressure ventilation, and it is much quicker and safer than administering succinylcholine or lidocaine. The technique also may be used to maintain a patent airway during mask anesthesia.The obvious question is, Why does it work? Unfortunately, a sound, scientific answer cannot be provided. It works in part because forward displacement of the mandible corrects airway obstruction caused by the tongue falling back against the posterior pharyngeal wall. However, contrary to the recommendation that painful stimulation be avoided, an essential component of the treatment is the severe pain that the patient experiences because of the firm pressure that is applied to the ramus of the mandible, the facial nerve, and perhaps the deep lobe of the parotid gland. The parotid gland is innervated in part by the glossopharyngeal nerve, which in turn has connections with the vagus nerve and the superior cervical sympathetic ganglion by way of the petrosal ganglion. [10]The interconnections of the nerves at this location are complex and specific functions are not completely understood. It is likely that the painful stimulus relaxes the vocal folds and vocal cords by way of either the parasympathetic or sympathetic nervous systems.The thanks Helen Cambron, R.N., for the illustration.C. Philip Larson, Jr., M.D.Professor Emritus; Anesthesia and Neurosurgery; Stanford University; Professor of Clinical Anesthesiology; UCLA School of Medicine;plarson@ucla.edu(Accepted for publication June 11, 1998.)

American Society of AnesthesiologistsPhilip C. Larson, MD

Deep vs Awake

Some patients need to be wide awake before you remove the tube - think your bowel obstructions, your emergency unfasted surgeries etc - but for many elective intubations, you can consider a deep extubation if you feel so inclined.

The benefits are:

• More comfortable for the patient
• Less coughing
• Less haemodynamic, intraocular and intracranial pressure silliness
• You can wheel them round to recovery sooner

With regards to laryngospasm, it doesn't seem to matter a whole lot whether you extubate deep or awake, so long as you leave them alone when they're in a shallow plane of anaesthesia.

Negative pressure pulmonary oedema

If you attempt to suck a deep breath in against a closed glottis, you significantly reduce the intrathoracic pressure.

This produces a hydrostatic pressure gradient from the pulmonary capillaries into the alveoli, effectively sucking plasma into the lungs, and producing pulmonary oedema.

Fortunately this doesn't tend to happen during the usually brief periods of laryngospasm that are more commonly encountered, but if it goes on for long enough, the patient is likely to try and take a breath in sooner or later.

The treatment is largely supportive, with intubation and ventilation as required and PEEP or CPAP to help the oedema resolve.

Suction vs PEEP

When I extubate a patient, I set my APL valve to around 10-20cmH2O of PEEP right up until the tube is out, for the following reasons:

• It helps keep the lungs recruited
• It fills the FRC with 100% oxygen
• When the cuff is deflated, the positive pressure blows any secretions up and out of the trachea
• If the patient flops into laryngospasm, they've hopefully got at least a moderately decent reservoir of oxygen to use while I faff about fixing it
• It might reduce the incidence of negative pressure pulmonary oedema by briefly inhibiting inspiration via the Hering-Breuer reflex but this is entirely guesswork by yours truly

Most of the anaesthetists I've spoken to do something similar to this, but there is a cohort of consultants that I've worked with who actively suction down the ET tube while pulling the tube out.

I do not understand this.

I feel this is a very good way to irritate the vocal cords, empty the FRC, derecruit the lungs and invite laryngospasm to play.

But they are consultants and I am not, so here's something a bit more official to back up my bold claims.

Positive Airway Pressure at Extubation Minimizes Subglottic Secretion Leak In Vitro - PubMed

Accumulated secretion above the endotracheal tube cuff can be aspirated during extubation after deflation. The possible techniques for minimizing pulmonary aspiration from subglottic secretion during extubation have not been well explored. This study aimed to determine the effect of different extuba …

PubMedTzu-Pei Wang

Positive versus negative pressure during removal of endotracheal-tube on prevention of post-extubation atelectasis in ventilated neonates: A randomized controlled trial - PubMed

The use of positive pressure during removal of the endotracheal tube in newborn infants reduced the rate of PEA compared with the negative pressure so extubation by a positive pressure is recommended in neonates.

PubMedRoya Farhadi

As with everything in anaesthesia - you are allowed to make up your own mind about the best way to do things.

Useful Tweets

References and Further Reading

Laryngospasm in anaesthesia

Laryngospasm is the sustained closure of the vocal cords resulting in the partial or complete loss of the patient’s airway. Although described in the consc

OUP Academicrobert.walkercmft.nhs.uk

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