Pain assessment in turning procedures for patients with invasive mechanical ventilation

The assessment of pain is particularly difficult in critical patients unable to self-report or with cognitive impairment. In such cases, the use of scales which evaluate pain through patient behaviour is important.

To compare the behavioural responses to pain, measured on the Critical-Care Pain Observation Tool (CPOT) scale, and the physiological responses prior to, during and after the positioning procedure in patients with invasive mechanical ventilation. We also sought to analyse whether there are differences in the CPOT scores between medical and surgical patients, and between conscious and unconscious patients.

Pain scores were evaluated in 96 patients. The data gathering was carried out 1 min before, during and 10 min after the turning by means of the CPOT scale which includes four behavioural indicators, each indicator scored from 0 to 2. Likewise, mean arterial pressure (MAP), heart rate (HR), respiratory rate (RR) and arterial oxygen saturation (SpO(2)) were recorded.

The total mean score on the CPOT scale prior to the positioning procedure was 0·27; during turning it was 1·93 and 0·10 after the procedure (p < 0·05). Facial expression was the indicator that increased most with reference to the baseline situation, followed by body movements; compliance with the ventilator, and finally, muscle tension. There were also slight variations in these physiological variables during the turning procedure (p < 0·05). The total mean score on the CPOT scale during the turning of surgical patients was 2·02 and 1·80 for medical patients (p = 0·162).

The observation of the patient's behaviour during the turning and the physiological changes produced allow professionals to objectify pain in critical patients with verbal communication difficulties. Moreover, our results also highlight the need to administer of additional analgesia before a painful procedure, particularly in post-surgical patients.

The good measurement qualities of the CPOT scale obtained during a painful procedure recommend its use in intensive care units (ICUs) for adult patients with artificial ventilation.