Differences in Clinical Outcomes According to Weaning Classifications in Medical Intensive Care Units

Abstract

BackgroundAlthough the weaning classification based on the difficulty and duration of the weaning process has been evaluated in the different type of intensive care units (ICUs), little is known about clinical outcomes and validity among the three groups in medical ICU. The objectives of this study were to evaluate the clinical relevance of weaning classification and its association with hospital mortality in a medical ICU with a protocol-based weaning program.MethodsAll consecutive patients admitted to the medical ICU and requiring mechanical ventilation (MV) for more than 24 hours were prospectively registered and screened for weaning readiness by a standardized weaning program between July 2010 and June 2013. Baseline characteristics and outcomes were compared across weaning classifications.ResultsDuring the study period, a total of 680 patients were weaned according to the standardized weaning protocol. Of these, 457 (67%) were classified as simple weaning, 136 (20%) as difficult weaning, and 87 (13%) as prolonged weaning. Ventilator-free days within 28 days decreased significantly from simple to difficult to prolonged weaning groups (P < 0.001, test for trends). In addition, reintubation within 48 hours after extubation (P < 0.001) and need for tracheostomy during the weaning process (P < 0.001) increased significantly across weaning groups. Finally, ICU (P < 0.001), post-ICU (P = 0.001), and hospital (P < 0.001) mortalities significantly increased across weaning groups. In a multiple logistic regression model, prolonged weaning but not difficult weaning was still independently associated with ICU (adjusted OR 8.265, 95% CI 3.484–19.605, P < 0.001), and post-ICU (adjusted OR 3.180, 95% CI 1.349–7.497, P = 0.005), and hospital (adjusted OR 5.528, 95% CI 2.801–10.910, P < 0.001) mortalities.ConclusionsWeaning classification based on the difficulty and duration of the weaning process may provide prognostic information for mechanically ventilated patients who undergo the weaning process.

Variation in Definition of Prolonged Mechanical Ventilation

“…Better understanding of the relationship between the duration of mechanical ventilation and important patient outcomes such as weaning success and mortality may be useful to guide discussions of prognosis with patients and their families, facilitate clinical decision making, and to set goals of care 1,2 . Many studies have attempted to identify predictors of prolonged mechanical ventilation (PMV) [3][4][5] as well as development of mortality risk prediction models for patients requiring 21 6 and 14 days of mechanical ventilation 7 .…”

Differences between prolonged weaning patients from medical and surgical intensive care units

“…This is highlighted by the fact that although patients from medical ICUs tended to have more underlying pulmonary diseases, blood gases at the time of referral to the weaning unit were not different between the patient groups. 18 However, comparison of data seems difficult as patient groups are only small and, although the described studies used weaning strategies according to recommended criteria, 7 local, structural opportunities, and patient mix might be different. show that once common problems that impact on the ability to wean patients from mechanical ventilation 7 (e.g., respiratory and cardiac load, neuromuscular, neuropsychological, metabolic, nutrition, anemia) are positively addressed by a specialized multidisciplinary team, the mortality rate is not affected by the reason for which patients were initially admitted to an ICU.…”

The Process of Weaning from Mechanical Ventilation

“…A number of studies [57][58][59][60][61][62] have evaluated this classification. In these studies, the incidence of the simple weaning group was 30-67% of all patients in whom an SBT was attempted (Fig.…”

“…A summary of these studies [57][58][59][60][61][62] indicates that simple and difficult weaning groups are similar in terms of mortality, re-intubation, tracheostomy, and ICU stay ( Table 2). The prolonged weaning group, however, has been associated with worse outcomes and higher mortality (Table 2).…”