Anaesthesia for epiglottitis

*notes taken from local master student program

Anaesthesia for epiglottitis

An acute inflammation and swelling of the epiglottis, the aryepiglottic folds and the mucosa over the arytenoid cartilages, usually associated with Haemophilus influenzae type B, but increasingly with beta haemolytic streptococcus.

It occasionally results in complete laryngeal obstruction, and death from hypoxia. Although epiglottitis was considered to be primarily a paediatric disorder, with a peak incidence between the ages of 1 and 4 years, there has been a dramatic decrease in its incidence in children.

This is probably the result of the introduction ofan effective vaccine against H. influenzae type B (Rhine & Roberts 1995, Park et al 1998). By contrast, the adult incidence is now increasing.

The use of antibiotics during childhood may mean that adults have less immunity to H. influenzae; in addition, a significant percentage of adults with the disease are immunocompromised. However, children and adults present with slightly different clinical features.

In children, the treatment of choice is short-term nasotracheal intubation, until the swelling has subsided. 

In adults, nasotracheal intubation may also be required, but the clinical course can be less severe than in children, so that an increasing number of clinicians are adopting a more conservative policy (Wolf et al 1990,Medical disorders and anaesthetic problems Epidermolysis bullosa (EB) Crosby & Reid 1991).

However, sudden death is still reported, even in adults, and such a change is not universally accepted.

Presentation

1. Although, since the Hib vaccine, epiglottitis in children has become rare, it is still worthwhile describing the clinical features. In children, the illness was usually of sudden onset (6–12 h), with high fever, marked constitutional symptoms, stridor, the development of a muffled voice, and the absence of a harsh cough.

The child was agitated and often leaned forward,drooling saliva, because he/she was unable to swallow. Boys were more frequently affected than girls.

Although before the introduction of the Hib vaccine the peak incidence was in the age group 2–4 years, some cases were reported in younger children, in whom the presentation

could be atypical (Emmerson et al 1991).

2. In children, differentiation from laryngotracheobronchitis was sometimes difficult. In a prospective study, three findings on

physical examination were associated with epiglottitis (Mauro et al 1988): drooling, agitation, and the absence of spontaneous cough.

3. The child sometimes presented with increasing respiratory distress and cyanosis. Total airway obstruction could be sudden and without warning. Occasionally, cardiorespiratory arrest occurred before hospital admission.

4. A high leucocyte count, and, in the past,H. influenzae type B was often grown from blood culture or swabs.However, since the

introduction of Hib vaccine, a beta haemolytic streptococcus is now more commonly seen.A lateral X-ray of the neck may show a swollen epiglottis.

However, if epiglottitis is suspected,the patient should only be sent to X-ray accompanied by an experienced member of staff, in case of sudden respiratory obstruction.

5. Adults are more likely to complain of dysphagia and painful swallowing, and one-third presented with shortness of breath (Hebert et al 1998).
However, there is still the risk of sudden airway obstruction.The reported death rates vary, partly because of the small numbers in each study. Of 56 adult cases of epiglottitis, death occurred in four.
Two of these were in hospital under observation, and both died before airway intervention had been undertaken (Mayosmith

et al 1986).
Overall death rates from an 813-patient cohort in Canada were 1.2%, whereas in the detailed review of 51 patients admitted to two tertiary care hospitals there were no deaths (Hebert et al 1998).

6. In adults, epiglottitis is increasingly associated with patients who are immunocompromised, with conditions such as HIV, drug and alcohol abuse.There is a high incidence in smokers (Hebert et al 1998).

Anaesthetic problems

1. Although the distinction between acute epiglottitis and acute laryngotracheobronchitis, the other more common cause of stridor, can frequently be made on clinical grounds, occasionally the diagnosis is difficult.

2. In children, examination of the mouth and throat, or even distress caused by insertion of an iv infusion, may precipitate complete upper airway obstruction.

3. Induction of anaesthesia may abolish accessory respiratory muscle movement, and also cause obstruction.

4. Perioperative complications include cardiorespiratory arrest, accidental extubation, tracheal tube blockage, pulmonary oedema, and pneumothorax.
A report of 161 cases of epiglottitis revealed 45 complications in 34

patients and five deaths (Baines et al 1985). 
Complications included 18 episodes of cardiorespiratory arrest, ten incidents involving accidental extubation, three cases of pneumothorax, and three episodes of pulmonary oedema following relief of the obstruction.

5. Pulmonary oedema has occurred after intubation in 2% of children, usually those with Medical disorders and anaesthetic problems Epiglottitis=severe obstruction progressing to respiratory arrest (Bonadio & Losek 1992). 

In adults, the presence of a cardiac problem may increase the

incidence of this complication. 
Postobstructive pulmonary oedema occurred in a 36 year old

with severe coronary artery disease (Wiesel et al

1993).

6. The appearance of an ampicillin-resistant H. influenzae strain was reported in the early 1990s (Emmerson et al 1991), and the use of a cephalosporin is now more common.

7. In adults, elective intubation carries risks, therefore medical treatment is more often considered.
However, this must only be carried out when there are staff at hand who are experienced at managing the emergency airway.

Management

1. Acute epiglottitis represents a serious emergency that should be attended by an experienced anaesthetist, whenever the diagnosis is suspected.
In any child with stridor a high index of suspicion must be maintained.

Investigation should not be allowed to delay the treatment of life-threatening obstruction.

2. In children, no examination of the throatshould be made, except under an anaesthetic given by an experienced anaesthetist, and preferably with an ENT surgeon present.

3. In adults, in contrast, an accurate diagnosis of moderate to severe epiglottitis is important and a nasoendoscopic view of the larynx, without the application of local anaesthetic,may be obtained by an experienced endoscopist, without the risk of precipitating complete obstruction (Hebert et al 1998).

4. In adults, conservative management is increasingly used. In general, patients are divided into those who need immediate emergency intubation, those who have elective intubation because of a deterioration during observation, and those who require medical treatment only.

However, it is still possible to precipitate complete airway obstruction, therefore should this approach be used, the endoscopist should be experienced, and the facility for emergency tracheostomy immediately available.

5. Although there is no reliable method of predicting those who will obstruct (Park et al 1998), one study in adults found that dyspnoea at the time of admission predicted the need for intubation (Hebert et al 1998).

6. Traditionally, when intubation is required, inhalation anaesthesia with halothane and oxygen, with or without nitrous oxide,was used.

Some authors now consider sevoflurane to be a superior agent (Milligan 1997, Spalding & Ala- Kokko 1998).
However, at high concentrations, sevoflurane may cause respiratory depression and it can be difficult to achieve anaesthesia deep

enough, or for a long enough period.
Young (1999) described an uneventful induction in the sitting position, but when the patient was laid supine, apnoea and obstruction occurred.
These controversies are now more difficult to resolve, because of the small number of patients requiring intervention.

7. Once the patient is sufficiently deep, the airway should be secured, first with an oral tube.

This can be replaced at leisure with a suitably sized nasotracheal tube

8. The tube must be firmly fixed and an intravenous infusion set up to prevent dehydration.
However, it is amazing how rapidly a small child can remove a tracheal tube or cannula that is inadequately secured. 
Firm bandaging of the hands will reduce the risks of self-extubation.
The emergency use of a Seldinger minitracheostomy kit has been reported in two adults (Ala-Kokko et al 1996).

9. In those patients with severe obstruction,

pulmonary oedema may occur after intubation.

Management requires airway patency, oxygen,

and, in about 50% of cases IPPV and PEEP

(Lang et al 1990).

10. One of the most difficult problems is to provide sufficient humidification to prevent crusting of the tube. Examination under anaesthesia at 24 h is advisable. Even if Medical disorders and anaesthetic problems Epiglottitis extubation is not possible at this stage, the tube should be changed. 
In a small child, partial blockage of the tube by secretions is almost invariably found.
The mean duration of intubation in one series was 36 h (Rothstein & Lister 1983). Direct observation of the epiglottis was found to be the only reliable way to determine the stage at which the tube was no longer necessary.

11. Anaesthetists are divided over the best method of managing the patient, once intubated. 
Increasingly, IPPV is used for the period of tracheal intubation, to allow adequate sedation, oxygenation, and humidification.

However, in a study of 349 patients (Butt et aln 1988), 83% received nasotracheal intubation and were allowed to breathe spontaneously through a condenser humidifier. No sedation was given but the patient was restrained. 
Criteria for extubation were: the resolution of fever to <37.5°C, the time of intubation (12–16 h), and general improvement in appearance. 
It was accepted that this scheme of management requires the invariable presence on the ITU of someone experienced in intubation. 
If the patient is allowed to breathe spontaneously, a sedative, but not a respiratory depressant, may be permitted.
Accidental extubation and tracheal tube blockage are the most serious complications, and ones that can prove fatal if respiration is depressed.
Whichever method is employed, facilities should be available for rapid reintubation.

12. Whereas ampicillin used to be the drug of choice, there is increasing evidence of ampicillin resistance. Cephalosporins are now more commonly used.
Antibiotics should be given empirically; the insistence on having

bacteriological specimens before antibiotics are given may be unnecessary and potentially hazardous.

13. Racemic epinephrine administered in a nebulizer (1 mg in 5 ml 0.9% saline) has been reported to improve symptoms in an adult with epiglottitis (MacDonnell et al 1995).

14. The use of steroids is debatable.A retrospective uncontrolled comparison between one area using them routinely and one only using them occasionally, showed no difference in outcome (Welch & Price 1983).
However, in practice, steroids are often given.Those patients who fail the first attempt at extubation may benefit from a course of prednisolone 2mgkg–1day–1 before the second attempt

(Freezer et al 1990).

15. Short-lived pulmonary oedema occasionally occurs after relief of the obstruction, and should be treated with oxygen, or if necessary, IPPV (Lang et al 1990).