Volume 1 Supplement 1

17th International Symposium on Intensive Care and Emergency Medicine

Open Access

APACHE II score is better than weaning indices in predicting prolonged mechanical ventilator dependence

  • B Afessa1,
  • L Hogans1,
  • R Murphy1,
  • P Kubilis1 and
  • B Meyers1
Critical Care19971(Suppl 1):P066

DOI: 10.1186/cc64

Published: 1 March 1997

Introduction

Spontaneous minute ventilation (VE), peak inspiratory airway pressure (Plmax), rapid shallow breathing index (f/vT), relative inspiratory effect (RIE), and the P(A-a)O2, blood urea nitrogen and gender score (A + B + G) are used in predicting weaning success. Some patients are transferred from intensive care to subacute care facilities when prolonged mechanical ventilation (MV) is anticipated. This prospective. observational study compares the role of weaning indices versus APACHE II score in identifying patients requiring prolonged MV.

Methods

The study included 84 patients referred for weaning assessment, when their underlying acute conditions had stabilized but immediate successful extubation was not expected. Plmax, VE and respiratory rate were measured. APACHE II score. f/VT, RIE, and A + B + G were calculated. Prolonged and successful weaning were defined as dependance on MV for ≥ 7 and < 7 days respectively from the day of weaning assessment. Weaning outcome was categorized into three: death, prolonged weaning, and successful weaning. Student's t-test was used to compare differences in means. P value < 0.05 was considered significant.

Results

Patients' mean age was 55.9 ± 13.8 years: 42 were male; 42 were black, 41 white and 1 Hispanic. The main causes of the respiratory failure were pneumonia (25) and COPD (17). The patients had been on MV for a median of 9 days before weaning assessment. Eleven (13%) patients died: 22 (26%) had prolonged weaning: 51 (61%) were successfully weaned. The mean APACHE II score and weaning indices are listed in the table.

Conclusions

This study suggests that patients' overall physiologic condition, measured by APACHE II score, is a better predictor of prolonged mechanical ventilator dependence than weaning indices.

Table

  

Prolonged

Successful

P value

 

Dead

weaning

weaning

P1

P2

APACHE II

21.2

17.3

12.6

0.0410

0.0010

VE (l/min)

9.5

9.6

10.3

0.9575

0.4480

PImax (cm H2O)

53

44

59

0.2491

0.0169

f/VT

120

95

87

0.2955

0.5532

RIE

0.406

0.605

0.507

0.1588

0.2877

A+B+G

39

56

54

0.0077

0.6062

P1 comparing dead versus prolonged weaning; P2 comparing prolonged weaning versus successful weaning

Authors’ Affiliations

(1)
University of Florida Health Science Center

Copyright

© Current Science Ltd 1997

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