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