Validation of Dysfunctional Ventilatory Weaning Response

Abstract

PURPOSETo further clinically validate the defining characteristics of dysfunctional ventilatory weaning response (DVWR) in patients requiring long‐term mechanical ventilation.METHODSThe Weaning Readiness Assessment Scale (WRAS), a 28‐item, 60‐point scale used to assess patients' readiness to wean from mechanical ventilation, was used to collect data on a large data set of 533 patients who were on mechanical ventilation >4 days. Data were collected every other day until the patient was weaned, discharged, or expired. The WRAS is comprised of two subscales: the physiological/behavioral (PPBB) subscale and ventilatory subscale (VVV).FINDINGSA content validity index of 0.88 indicated that the variables and their scoring ranges were appropriate for the study population. Interrater and test‐retest reliability measures were 0.93 and 0.92, respectively. Internal consistency (Cronbach's alpha, p<0.05) for the PPBB and VVV subscales were .69 and .76, respectively. Data were available on 533 subjects and analyzed by principal component extraction with varimax rotation, resulting in a two‐factor solution with strong loadings for 17 variables. In addition, preliminary one‐way analysis of variance showed statistical significance (p<0.05) on these 17 variables. Where statistical significance was not present, the trend was in the expected direction.DISCUSSIONThese data imply that 10 of the 17 variables alone and in combination affect weaning from mechanical ventilation and lend support to the existing defining characteristics of DVWR. In addition, data revealed 7 statistically significant symptom variables affecting weaning from mechanical ventilation that are currently not listed as defining characteristics for DVWR: need for multiple vasopressors, fluid overload, multiple antibiotic use, bronchodilator use, need for high FiO2, and high PEEP levels.CONCLUSIONSFor most patients, weaning from mechanical ventilation is a smooth transition. Patients who require >3 days of mechanical ventilation are an expensive patient population for acute care hospitals. Forty percent to 42% of mechanically ventilated patients either fail the initial spontaneous breathing trial (24%) or are extubated and require reintubation (16%–18%). The weaning process for long‐term mechanically ventilated patients has fiscal and psychosocial ramifications for the patient, family and friends, and healthcare providers.