Association between diastolic dysfunction and fluid balance in critically ill patients during weaning from mechanical ventilation.

OBJECTIVE

To assess the role of diastolic dysfunction and fluid balance in weaning failure.

DESIGN

Prospective, observational, single center.

SETTING

Intensive care unit of a university hospital.

PATIENTS: Adult patients on mechanical ventilation for more than 48 h who underwent a spontaneous breathing trial (SBT).

INTERVENTIONS: Echocardiography was performed immediately before and at the end of SBT. Patients were classified into two groups according to weaning outcome.

MAIN VARIABLE OF INTEREST: Weaning failure.

RESULTS

Among 89 patients included, weaning failure occurred in 33 patients (37%). Isolated diastolic dysfunction at the end of the SBT was more frequent in the failure group (39.3% vs. 17.8%, p = 0.025). Average daily fluid balance from ICU admission until first SBT was less negative in patients who failed than in those who succeed in the weaning (-648 mL [-884 to -138] vs. -893 mL [-1284 to -501], p = 0.007). Average daily fluid balance from the first SBT until the ICU discharge was more negative in the weaning failure than in the success group (-973 mL [-1493 to -201] vs. -425 mL [-1065 to 12], p = 0.034). Cox regression analysis showed that diastolic dysfunction was not an independent factor related to weaning failure but needed the association of positive fluid balance and age.

CONCLUSIONS

Weaning failure due to diastolic dysfunction is highly related to fluid balance, and the deleterious effect of fluid balance on diastolic function is associated with age The timing of fluid removal could play a key role in this scenario.