Background: The evaluation of pain in patients, unable of oral communication, often relies on behavioral assessment. However, some critically ill patients, while non-verbal, are awake and have some potential for self-reporting. The objective was to compare the results of a behavioral pain assessment with self-reporting in awake, non-verbal, critically ill patients unable to use low-tech augmentative and alternative communication tools.

Methods: Prospective cohort study of intubated or tracheotomized adult, ventilated patients with a RASS (Richmond Agitation Sedation Scale) of -1 to + 1 and inadequate non-verbal communication skills in a surgical intensive care unit of a tertiary care university hospital. For pain assessment, the Behavioral Pain Scale (BPS) was used. Self-reporting of pain was achieved by using an eye tracking device to evaluate the Numeric Rating Scale (NRS) and the pain/discomfort item of the EuroQol EQ-5D-5 L (EQ-Pain). All measurements were taken at rest.

Results: Data was collected from 75 patients. Neither the NRS nor the EQ-Pain (r < .15) correlated with the BPS. However, NRS and EQ-Pain were significantly correlated (r = .78, p = < 0.001), indicating the reliability of the self-reporting by these patients. Neither the duration of intubation/tracheostomy, nor cause for ICU treatment, nor BPS subcategories had an influence on these results.

Conclusions: Behavioral pain assessment tools in non-verbal patients who are awake and not in delirium appear unreliable in estimating pain during rest. Before a behavioral assessment tool such as the BPS is used, the application of high-tech AACs should be strongly considered.