Effectiveness of a spontaneous breathing trial with a low-pressure support protocol for liberation from the mechanical ventilator in a general surgical ICU

Introduction

Discontinuing patients from mechanical ventilation is an important problem in ICUs. The aim of this study is to compare the effectiveness between a spontaneous breathing trial with a low-pressure support protocol and a liberal or nonprotocol-directed method.

Methods

We conducted a retrospective cohort study involving 577 patients who were arranged and appropriate for weaning from mechanical ventilation on a general surgical ICU in an academic university-affiliated hospital between 1 July 2003 and 30 June 2007. Two hundred and twenty-two patients (Liberal group) had weaning process orders that depended on their physicians. Three hundred and fifty-five patients underwent a once-daily spontaneous breathing trial with a low-pressure support protocol. Patients assigned to this protocol had the pressure support level decreased to 5–7 cmH₂O for up to 2 hours each day. If signs of intolerance occurred, assisted control ventilation was reinstituted for 24 hours. Patients who tolerated a 2-hour trial without signs of distress were extubated. We collected demographic data, cause of ICU admission, APACHE II score at arranged time of weaning, the weaning process time, ventilator days and ICU length of stay.

Results

There were no statistical differences between liberal and protocol groups in age (59.2 ± 19.3 vs 55.6 ± 19.8 years; P = 0.03), gender (male 74.3 vs 67.9%; P = 0.2) and APACHE II score at arranged time of weaning (14.7 ± 7.4 vs 15.3 ± 6.3; P = 0.2). The mean duration of the weaning process was 72.1 ± 101.3 hours in the liberal group and 7.7 ± 16.8 hours in the protocol group (P < 0.01). The mean ventilator days and length of ICU stay were statistically different between the liberal and protocol groups (5.7 ± 2.8 vs 2.7 ± 2.3; and 7.3 ± 7.1 vs 4.4 ± 3.4 days, respectively; P < 0.01) (Figure 1).

Figure 1

Conclusion

The spontaneous breathing trial with a low-pressure support protocol for liberation from the mechanical ventilator was effective in the general surgical ICU.