Validation of the withdrawal assessment tool-1 (WAT-1) in pediatric cardiovascular patients on an inpatient unit

Purpose: Sedation and analgesia are administered to critically ill patients, which may result in physical dependence and subsequent iatrogenic withdrawal. The Withdrawal Assessment Tool-1 (WAT-1) was developed and validated as an objective measurement of pediatric iatrogenic withdrawal in intensive care units (ICUs), with a WAT-1 score ≥ 3 indicative of withdrawal. This study's objectives were to test interrater reliability and validity of the WAT-1 in pediatric cardiovascular patients in a non-ICU setting.

Design and methods: This prospective observational cohort study was conducted on a pediatric cardiac inpatient unit. WAT-1 assessments were performed by the patient's nurse and a blinded expert nurse rater. Intra-class correlation coefficients were calculated, and Kappa statistics were estimated. A two-sample, one-sided test of proportions of weaning (n = 30) and nonweaning (n = 30) patients with a WAT-1 ≥3 were compared.

Results: Interrater reliability was low (K = 0.132). The WAT-1 area under the receiver operating curve was 0.764 (95% confidence interval; ± 0.123). There was a significantly higher proportion (50%, p = 0.009) of weaning patients with WAT-1 scores ≥3 compared to the nonweaning patients (10%). The WAT-1 elements of moderate/severe uncoordinated/repetitive movement and loose, watery stools were significantly higher in the weaning population.

Practice implications: Methods to improve interrater reliability warrant further examination. The WAT-1 had good discrimination at identifying withdrawal in cardiovascular patients on an acute cardiac care unit. Frequent nurse re-education may increase accurate tool use. The WAT-1 tool may be used in the management of iatrogenic withdrawal in pediatric cardiovascular patients in a non-ICU setting.