Predicting successful weaning in a cohort of elderly patients

Introduction

Aging causes structural and functional modifications in the respiratory system. The evidence that these changes could impair weaning in elderly patients, until now, was not clear. We designed a protocol to study possible differences between an adult group (AG, up to 60 years) and an elderly group (EG, >60 years) in a daily screening trial.

Methods

One hundred and forty-four patients (79 EG and 65 AG) were studied. The primary outcome was weaning success (48 hours of spontaneous ventilation after extubation). The secondary outcome was differences in the conventional weaning predictors. Parameters studied included: respiratory rate (f), tidal volume (VT), frequency–tidal volume ratio (f/VT), gasometric and ventilatory parameters. The weaning method was a spontaneous breathing trial. Measurements were performed twice: just before the spontaneous breathing trial (T1) and 30 minutes after (T2). The chi-square test, analysis of variance and t test were used in the analysis.

Results

Weaning success was 86% both in EG and AG (P = 0.989). There were no differences in gasometric and in ventilatory parameters between groups. Comparisons in TI and T2 in AG and EG are presented in Table 1. Sensitivities of f/VT in T1/T2 were: for EG, 94 (86–98)/96 (89–98); for AG, 95 (86–99)/100 (94.8–100).

Table 1 (abstract P173)

Conclusion

The weaning success in our study is similar to that described in other trials. Older patients showed differences in f, VT and f/VT when compared with adults. However, there were no differences in weaning success.