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Critical Care

Open Access

Predicting successful weaning in a cohort of elderly patients

  • C Corbellini1,
  • A Guntzel1,
  • C Trevisan1 and
  • S Vieira1
Critical Care200711(Suppl 2):P173

Published: 22 March 2007


Public HealthElderly PatientPrimary OutcomeVolume RatioRespiratory Rate


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.


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.


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)

Weaning criteria

T1 AG (n = 65)

T2 AG (n = 65)

T1 EG (n = 79)

T2 EG (n = 79)

f (breaths/min)

22 ± 59*

22 ± 5.2*

24 ± 5.5*

24 ± 5.4*

VT (ml)

560 ± 200*

550 ± 180*

470 ± 170*

480 ± 150*


47 ± 24*

46 ± 19*

59 ± 28*

56 ± 24*

*P < 0.05 comparing AG and EG.


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.

Authors’ Affiliations

Hospital de Clinicas de Porto Alegre, Brazil


© BioMed Central Ltd. 2007