Weaning from mechanical ventilation: a cross-sectional study of reference values and the discriminative validity of aging.

[Purpose] To evaluate pre-extubation variables and check the discriminative validity of age as well as its correlation with weaning failure in elderly patients. [Subjects and Methods] Two hundred thirty-nine consecutive patients (48% female) who were on mechanical ventilation and had undergone orotracheal intubation were divided into four subgroups according to their age: <59 years, 60-69 years, 70-79 years, and >80 years old. The expiratory volume (VE), respiratory frequency (f), tidal volume (VT), and respiratory frequency/tidal volume ratio (f/VT) were used to examine differences in weaning parameters between the four subgroups, and age was correlated with weaning failure. [Results] The rate of weaning failure was 27.8% in patients aged >80 years and 22.1% in patients aged <60 years old. Elderly patients presented higher f/VT and f values and lower VT values. The areas under the receiver operating characteristic curves for f/VT ratio were smaller than those published previously. [Conclusion] Our results indicate that aging influences weaning criteria without causing an increase in weaning failure.

Weaning predictors do not predict extubation failure in simple-to-wean patients.

BACKGROUND: Predictor indexes are often included in weaning protocols and may help the intensive care unit (ICU) staff to reach expected weaning outcome in patients on mechanical ventilation. OBJECTIVE: The objective of this study is to evaluate the potential of weaning predictors during extubation. DESIGN: This is a prospective clinical study. SETTINGS: The study was conducted in 3 medical-surgical ICUs. PATIENTS: Five hundred consecutive unselected patients ventilated for more than 48 hours were included. METHODS AND MEASUREMENTS: All patients were extubated after 30 minutes of successful spontaneous breathing trial and followed up for 48 hours. The protocol evaluated hemodynamics, ventilation parameters, arterial blood gases, and the weaning indexes frequency to tidal volume ratio; compliance, respiratory rate, oxygenation, and pressure; maximal inspiratory pressure; maximal expiratory pressure; Pao(2)/fraction of inspired oxygen; respiratory frequency; and tidal volume during mechanical ventilation and in the 1st and 30th minute of spontaneous breathing trial. RESULTS: Reintubation rate was 22.8%, and intensive care mortality was higher in the reintubation group (10% vs 31%; P < .0001). The areas under the receiver operating characteristic curve showed that tests did not discriminate which patients could tolerate extubation. CONCLUSION: Usual weaning indexes are poor predictors for extubation outcome in the overall ICU population.