Determination of Psychometric Properties of Non-Verbal Pain Scale in Patients Receiving Mechanical Ventilation

Introduction: One of the major barriers to pain management is the lack of adequate scale for the assessment and diagnosis of pain in patients with no verbal response under mechanical ventilation in intensive care units. One of the few pain assessment scales in these patients is the Non-Verbal Pain Scale (NVPS).&nbsp; Objective: This study aimed to determine psychometric properties of Non-Verbal Pain Scale (NVPS) in patients under mechanical ventilation in intensive care units. Materials and Methods: In this methodological study, 60 patients under mechanical ventilation and admission to trauma, internal, neurological and surgical intensive care units were considered. The pain was assessed using NVPS by two nurses at six different times (before, during and after painful and non-painful procedures). Also, 8-12 hours after the initial test, a retest was performed in 37 out of 60 patients (randomly selected). Results: The Cronbach's &alpha; coefficient for the whole scale was obtained as 0.80 while the correlation between the two raters at different times was 0.89-0.96, and the correlation between test and retest was 0.55-0.86. There was a significant difference in the pain score during painful and non-painful procedures (P=0.001) and a higher pain score in those who confirmed the presence of pain (P<0.001), indicating good discriminant and criterion validity of NVPS. Conclusion: NVPS has good psychometric properties and can be used as a valid and reliable scale for assessing pain in patients under mechanical ventilation.