[Clinical study of weaning predictors in COPD patients with prolonged mechanical ventilation].
OBJECTIVE
To evaluate the combined pulmonary function test at bedside as a predicting parameter of weaning in prolonged mechanically ventilated (MV) patients with chronic obstructive pulmonary disease (COPD).


METHODS
58 patients [mean duration of MV (18.4 +/- 9.2) d] who were divided into two groups were enrolled in this study. Group I included 43 patients [male 30, female 13, mean age (65 +/- 12) y] were successful in weaning, group II included 15 patients [male 10, female 5, mean age (64 +/- 10) y] were failed. ABGs, APACHEII, pulmonary function test and respiratory mechanics were measured in both groups after 30 minutes stable spontaneous breathing.


RESULTS
There were no significant difference in ABGs, APACHEII, oxygenation index (OI), dynamic compliance (Cdyn) and airway resistance (Raw) between two groups (all P values > 0.05). There were significant differences in the following parameters between two groups: vital capacity/tidal volume (VC/VT, 2.10 +/- 0.20 vs. 1.30 +/- 0.20), maximal inspiratory pressure (Pimax), (-21 +/- 4) vs. (-13 +/- 3) cm H2O, rapid shallow breath index (RSBI), f/VT, (74 +/- 30) vs. (115 +/- 20) times.min-1.L-1, all P values < 0.05. By the use of VC/VT(> 1.8), Pimax(< -18 cm H2O) and f/VT(< 105 times.min-1.L-1) as the criteria of weaning, the specificity (90%) was significantly higher than each of the above three parameters.


CONCLUSIONS
The bedside combined pulmonary function test (VC/VT, Pimax and f/VT) was a valuable weaning predictor in prolonged mechanically ventilated COPD patients.
Li
Y
Y
Guangzhou Institute of Respiratory Disease, Guangzhou 510120, China.
He
G
G
Chen
R
R
D000368:Aged; D000403:Airway Resistance / Q000502:physiology; D001784:Blood Gas Analysis; D005260:Female; D006801:Humans; D008170:Lung Compliance / Q000502:physiology; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D011237:Predictive Value of Tests; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood / Q000503:physiopathology / Q000628:therapy*; D012121:Respiration, Artificial / Q000379:methods*; D012129:Respiratory Function Tests; D013990:Tidal Volume / Q000502:physiology; D013997:Time Factors; D015300:Ventilator Weaning / Q000379:methods*; D014797:Vital Capacity / Q000502:physiology