Cristiane Brenner Eilert Trevisan

Noninvasive mechanical ventilation may be useful in treating patients who fail weaning from invasive mechanical ventilation: a randomized clinical trial

IntroductionThe use of noninvasive positive-pressure mechanical ventilation (NPPV) has been investigated in several acute respiratory failure situations. Questions remain about its benefits when used in weaning patients from invasive mechanical ventilation (IMV). The objective of this study was to evaluate the use of bi-level NPPV for patients who fail weaning from IMV.MethodsThis experimental randomized clinical trial followed up patients undergoing IMV weaning, under ventilation for more than 48 hours, and who failed a spontaneous breathing T-piece trial. Patients with contraindications to NPPV were excluded. Before T-piece placement, arterial gases, maximal inspiratory pressure, and other parameters of IMV support were measured. During the trial, respiratory rate, tidal volume, minute volume, rapid shallow breathing index, heart rate, arterial blood pressure, and peripheral oxygen saturation were measured at 1 and 30 minutes. After failing a T-piece trial, patients were randomly divided in two groups: (a) those who were extubated and placed on NPPV and (b) those who were returned to IMV. Group results were compared using the Student t test and the chi-square test.ResultsOf 65 patients who failed T-piece trials, 28 were placed on NPPV and 37 were placed on IMV. The ages of patients in the NPPV and IMV groups were 67.6 ± 15.5 and 59.7 ± 17.6 years, respectively. Heart disease, post-surgery respiratory failure, and chronic pulmonary disease aggravation were the most frequent causes of IMV use. In both groups, ventilation time before T-piece trial was 7.3 ± 4.1 days. Heart and respiratory parameters were similar for the two groups at 1 and 30 minutes of T-piece trial. The percentage of complications in the NPPV group was lower (28.6% versus 75.7%), with lower incidences of pneumonia and tracheotomy. Length of stay in the intensive care unit and mortality were not statistically different when comparing the groups.ConclusionThe results suggest that NPPV is a good alternative for ventilation of patients who fail initial weaning attempts. NPPV reduces the incidence of pneumonia associated with mechanical ventilation and the need for tracheotomy.Trial registrationCEP HCPA (02–114).

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.

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.