Weaning from mechanical ventilation: a model for extubation.
OBJECTIVE
To develop a model able to determine the right time for extubation and to validate its performance. paragraph sign


METHODS
A prospective clinical study.


METHODS
14-bed medical intensive care unit in a university hospital.


METHODS
101 patients (37 women/64 men) ventilated over more than 48 h (mean 10.4 +/- 10.3 days) and considered ready to be weaned by the medical team (February 1996-February 1998).


METHODS
This study included two series: a development series with 53 patients and a validation series with 48 patients. Before extubation, a weaning test was performed measuring tidal volume (V(T)), respiratory rate (f), f/V(T) ratio, minute ventilation, vital capacity (VC) and maximum inspiratory and expiratory pressures (MIP and MEP). The success of extubation was assessed after 48 h. Receiver operating characteristic (ROC) curves allowed the analysis of the discriminating power of each parameter. Threshold values were determined using the Youden's index. To create the best predictive model, we performed a multiple logistic regression analysis. To assess the calibration and the discrimination of the model, the Hosmer- Lemeshow goodness-of-fit test and area under ROC curves (AUC) were adopted.


RESULTS
In a development series, 60 tests were carried out with 38 successful extubations and 22 extubation failures. The multivariate analysis found three significant variables: VC (threshold value = 635 ml), f/V(T) ratio (threshold value = 88 breaths/min.l) and MEP (threshold value = 28 cmH(2)O). The validation cohort included 59 tests (38 successes and 21 failures). The validation series shows a good discrimination (AUC = 0.855 +/- 0.059) and calibration (goodness-of-fit test C: p = 0.224) of the model.


CONCLUSIONS
VC together with the f/V(T) ratio and MEP offer accurate prediction of early extubation.
Zeggwagh
A A
AA
Service de Réanimation Médicale, Hôpital Avicenne, B P 1005, 10001 Rabat, Morocco.
Abouqal
R
R
Madani
N
N
Zekraoui
A
A
Kerkeb
O
O
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002138:Calibration; D002985:Clinical Protocols / Q000592:standards*; D016002:Discriminant Analysis; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011446:Prospective Studies; D012123:Pulmonary Ventilation; D015203:Reproducibility of Results; D012119:Respiration; D012131:Respiratory Insufficiency / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D012680:Sensitivity and Specificity; D013990:Tidal Volume; D013997:Time Factors; D015300:Ventilator Weaning / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D014797:Vital Capacity