title: Rapid shallow breathing (frequency-tidal volume ratio) did not predict extubation outcome.
abstract: This was a prospective study of 52 patients that were extubated in our medical intensive care unit. Rapid shallow breathing, represented by a ratio of frequency to tidal volume (f/VT) of more than 105, was evaluated either on continuous positive airway pressure or pressure support prior to extubation as a marker of extubation outcome. Twelve out of 13 patients (92 percent) with rapid shallow breathing (f/VT ratio > 105) were successfully extubated. Out of 9 extubation failures only 1 patient had a f/VT ratio more than 105 (11 percent). A measured f/VT ratio of less than 105 had a sensitivity and specificity of 72 and 11 percent, respectively, for extubation success. Patients who had unsuccessful outcomes were ventilated for a significantly more prolonged period (9.6 +/- 6.8 d vs 4.6 +/- 3.9 d, unpaired t test, p = 0.004). We conclude that the presence of rapid shallow breathing during a weaning trial with the patient on partial ventilatory support does not necessarily preclude successful extubation.
authors.affiliation: Department of Medicine, National University Hospital, Singapore.
authors.forename: K H
authors.initials: KH
authors.lastname: Lee
authors.forename: K P
authors.initials: KP
authors.lastname: Hui
authors.forename: T B
authors.initials: TB
authors.lastname: Chan
authors.forename: W C
authors.initials: WC
authors.lastname: Tan
authors.forename: T K
authors.initials: TK
authors.lastname: Lim
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005544:Forecasting; D006801:Humans; D007442:Intubation, Intratracheal; D008171:Lung Diseases / Q000503:physiopathology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D011175:Positive-Pressure Respiration / Q000295:instrumentation; D011446:Prospective Studies; D012119:Respiration / Q000502:physiology*; D012121:Respiration, Artificial / Q000295:instrumentation; D012680:Sensitivity and Specificity; D015996:Survival Rate; D013990:Tidal Volume / Q000502:physiology*; D017211:Treatment Failure; D016896:Treatment Outcome; D015300:Ventilator Weaning