Criteria abstracted from The Users' Guide to Medical Literature, from the Health Information Research Unit and Clinical Epidemiology and Biostatistics, McMaster University

Highlighted lines and questions below provide links to the pertinent description of criteria in The EBM User's Guide, now available at the Canadian Centres for Health Evidence

Article Reviewed:

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Dexamethasone in the prevention of postextubation stridor in children.

Tellez DW, Galvis AG, Storgion SA, Amer HN, Hoseyni M, Deakers TW.

J Pediatr 1991;118:289-94. [abstract]

Reviewed by Adrienne Randolph

Review posted April 20, 1997

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I. What is being studied?:

The study objective:

To determine whether dexamethasone prevents postextubation airway obstruction in young children.

The patients included:

153 patients admitted to the PICU at Children's Hospital Los Angeles and Phoenix Children's Hospital who were mechanically ventilated and did not have any exclusion criteria.

The patients excluded:

1. Patients admitted for primary pharyngeal or laryngotracheal infection; 2. Patients receiving corticosteroids within 7 days before extubation; 3. Patients with surgical trauma to the upper airway; 4. Patients with a history of previous upper airway obstruction; 5. Patients with a medical condition contraindicating steroid use.

The interventions compared:

Dexamethasone IV 0.5 mg/kg per dose (maximum 10 mg) or normal saline with the first dose 6 to 12 hours before extubation and subsequent doses every 6 hours for a total of six doses.

The outcomes evaluated:

Postextubation stridor defined by symptoms of nasal flaring, prolonged inspiratory phase, and subcostal and sternal retractions or by use of aerosolized racemic epinephrine.

II. Are the results of the study valid?

Primary questions:

1. Was the assignment of patients to treatments randomized?

Yes. Randomization was done using a stratified scheme based on risk factors for postextubation stridor. These risk factors were age, duration of intubation (> or < 72 hours), upper airway trauma (unplanned extubations or > 1 intubation), circulatory compromise (systolic blood pressure < 5th %ile or previous hypotension requiring fluid resuscitation or cardiopulmonary bypass support), tracheal infection (fever with bacteria on gram stain and culture from two tracheal aspirates and white blood count >15,000 and no pulmonary infiltrates).

2. Were all patients who entered the trial properly accounted for and attributed at its conclusion?

Was followup complete?

Yes. All 153 enrolled patients were evaluated postextubation.

Were patients analyzed in the groups to which they were randomized?

Yes. No patients crossed over into the comparison group.

Secondary questions:

3. Were patients, health workers, and study personnel "blind" to treatment?

Yes. The medications were prepared by the pharmacy and the study was double blind; neither the patients nor the providers knew if they received dexamethasone or placebo.

4. Were the groups similar at the start of the trial?

Yes. The two groups were similar in age distribution, duration of endotracheal intubation, airway trauma, circulatory compromise, upper airway infection, and use of cuffed versus uncuffed endotracheal tubes.

5. Aside from the experimental intervention, were the groups treated equally?

Almost. Between trial entry and extubation the airway management was standardized with experienced operators. Neuromuscular blockade was used in patients requiring aggressive ventilator therapy, but its use in each group is not reported. There were more patients in the dexamethasone group who underwent reintubation (11% versus 5% in the saline group), but this was not statistically significant (P = 0.26). The reasons for reintubation are not explicitly stated.

III. What were the results?

1. How large was the treatment effect?

The overall risk of postextubation stridor was 25%. Dexamethasone was associated with a nonsignificant trend towards a reduced risk of postextubation stridor (Relative Risk 0.63; 95% CI 0.30, 1.31) and the results were the same after adjustment for age, duration of intubation and trauma. The study was stopped at 153 patients after this interim trend analysis. The authors state that there were no significant differences between groups in the average number of racemic epinephrine treatments or in the number of patients whose condition was refractory to therapy and who required reintubation. If one infers that the results for patients undergoing reintubation are actually for only patients reintubated for symptoms of postextubation airway obstruction, then dexamethasone was associated with a nonsignificantly higher risk of reintubation with 5% of patients reintubated in the saline group and 11% in the dexamethasone group (Relative Risk 2.28, 95% CI 0.73, 7.09).

2. How precise was the estimate of the treatment effect?

The confidence intervals (CI) reported above show that we can be 95% confident that the relative risk of postextubation stridor with dexamethasone is 70% better or 35% worse than with placebo.

IV. Will the results help me in caring for my patients?

1. Can the results be applied to my patient care?

Yes. The patient population is representative of patients in many PICU's. Management of the airway was done by experienced operators. The incidence of postextubation stridor was fairly high (25%). There was a trend towards a decreased risk of stridor in the dexamethasone group that may have reached significance with a larger sample. However, the results of this study do not support routine use of dexamethasone.

2. Were all clinically important outcomes considered?

Yes, but not clearly reported. The evaluation of significant stridor is clear. However, the reader must infer that the results reported for patients undergoing reintubation are actually for only patients reintubated for symptoms of postextubation airway obstruction. The actual number of patients who required racemic epinephrine treatments in each group is not reported.

3. Are the likely treatment benefits worth the potential harms and costs?

No. There is no proven benefit for use of dexamethasone.

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Related Reviews:

Anene O, Meert KL, Uy H, Simpson P, Sarniak AP. Dexamethasone for the prevention of postextubation airway obstruction: a prospective, randomized, double-blind, placebo-controlled trial. Crit Care Med 1996; 24: 1666-1669.

• Review, by A. Randolph

Harel Y, Vardi A, Quigley R, Brink LW, Manning SC, Carmody TJ, Levin DL. Extubation failure due to post-extubation stridor is better correlated with neurologic impairment than with upper airway lesions in critically ill pediatric patients. Int J Pediatr Otorhynolaryngal 1997; 39: 147-158.

• Review, by B. Markovitz

Comments

May 1, 1997

With respect to the two reviews on papers investigating post-extubation stridor: The review did not address the issue of assessing for ETT leak prior to inclusion in the randomization group. While neither showed tremendous benefit from the use of decadron, it appears to me that the study group was inappropriate. I would be more interested in seeing whether dex. relieves post-extubation stridor in patients whom you are reasonably sure will have it--ie, those who do not have a ETT leak at less than 20 cm H20. I am concerned that these two trials will lead to the assumption that dexamethasone is not useful in treating those those for whom it may actually be a benefit.

Laura Ibsen, MD (LIBSEN@chmca.org)
Children's Hospital Medical Center of Akron
Akron, Ohio

May 2, 1997

Thanks for the interesting assessment of the results of this dexamethasone trial. I would want to know the following: 1) why did the investigators terminate the trial? 2) what was their actual outcome measure and did they power the study appropriately for this measure? and 3) why did the investigators use chi-square analysis in their detemrination of risk? From the epidemiological standpoint, such an analysis is appropropriate mostly for exposure/no exposure studies. A preferable method would have been to determine the odds for stridor using logistic regression and adjusting for appropriate factors in the model. A another creative approach would be to use survival analysis, to determine whether or not the time to development of stridor was different between the groups.

Jay R. Shayevitz, MD (jayshay@umich.edu)
Providence Hospital and Medical Centers
Southfield, MI

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