The Science Journal of the American Association for Respiratory Care

1999 OPEN FORUM Abstracts

THE ENDOTRACHEAL TUBE AIR LEAK TEST: IS IT A PREDICTOR OF POST-EXTUBATION STRIDOR?

Kim, H.W., M.D. Assistant Professor, Dept of Pediatrics & Pediatric Critical Care Loma Linda University Children's Hospital, Loma Linda, CA Mink, R., M.D. Assistant Professor, Dept of Pediatrics & Pediatric Critical Care Harbor-UCLA Medical Center, Torrance, CA

BACKGROUND: The endotracheal tube air leak test (ALT) is currently used in many PICUs to predict the success of extubation. We conducted a prospective study in two tertiary PICUs to evaluate whether the ALT is a predictor of post-extubation stridor or the need for reintubation.

Methods: The ALT was performed by one investigator within 24 hours prior to extubation, as follows; 1) endotracheal tube was attached to an ambu-bag with pressure manometer and breathing gas circuit 2) stethoscope was placed over the larynx 3) pressure in the ambu-bag was slowly increased until air leak was auscultated 4) pressure on manometer was recorded 5) if no air leak was auscultated at 40 cm H2O, the ALT was terminated. Cuffed tubes (n=4) were deflated prior to the ALT. Air leak was defined as presence of an auscultated air leak below 20 cm H2O. Other data collected were duration of intubation, use of steroids prior to extubation, post-extubation stridor and reintubation. Statistical analysis used were t-Test and Chi-Square. Data are presented as mean ± SEM and p<0.05 was considered statistically significant.

Results: A total of 34 patients were evaluated (27<4 yrs of age, 7³4 yrs of age), 18 with air leak (AL) and 16 with no air leak (NAL). More patients in the NAL group had stridor (n=10) compared with the AL group (n=3, p=0.02). Evaluating all patients, the mean air leak pressure was higher (p=0.01) in patients with stridor (27.6±3.1) versus those without stridor (18.2±2.1). In the NAL group alone, the mean air leak pressure was not different in patients with (29.3±2.9) or without stridor (29.0±3.5). 16 patients received steroids, but no difference (p>0.05) was observed with the distribution of steroids used in groups (10/18 in AL, 6/16 in NAL). There was no association (p>0.05) between the use of steroids or the duration of intubation with stridor. All patients with stridor were treated with racemic epinephrine and one NAL patient failed extubation requiring reintubation.

CONCLUSION: The air leak test is a good predictor of post-extubation stridor. The likelihood of having post-extubation stridor is increased if there is no air leak below 20 cm H2O (predictive value 62%). However, since extubation failure is rare despite post-extubation stridor, physicians must carefully examine the benefits of prolonging intubation while awaiting the air leak pressure to fall below 20 cm H2O versus extubating patients and treating post-extubation stridor medically.

OF-99-188

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