[Postoperative pain: patient's self-report versus observer's rating.]

In 60 women undergoing vaginal hysterectomy, a total of 420 pain evaluations of postoperative pain intensity were performed by an observer and the patients. Pain intensity was rated by the observer on a visual analogue scale. The patients themselves evaluated their pain on a visual analogue scale and on a 101-point numerical rating scale. There was good agreement between pain intensity on the visual analogue scale and the 101-point numerical rating scale in the patients' self-assessment (r (2)=0.74;y=0.81x+11.4). The pain intensities determined by the observer on the visual analogue scale were markedly lower, on average than the patients' self-report (P<0.0001). The pain intensities rated by the observer on the visual analogue scale were on averange 37.7% of the patients' self-assessments on the visual analogue scale. The correlation between patients' self-assessments and observers' ratings was poor (r (2)=0.28;y=0.66x+31.3). There was also no clear correlation between pain intensity and heart rate or arterial blood pressure. A reliable assessment of pain intensity can only be performed by patients' self-assessment and not by observers' ratings.