Evaluation of obstetrical pain by a questionnaire of adjectives. Comparison of 2 epidural analgesia protocols

A French version of the McGill pain questionnaire, the "Questionnaire Douleur Saint Antoine" (QDSA), was assessed prospectively by comparing two epidural analgesia protocols using bupivacaine. One hundred women in labour who asked for epidural analgesia were randomly allocated to two groups and received either 0.25% or 0.5% bupivacaine (mean initial doses 32.5 and 50 mg respectively) with adrenaline 1 in 200,000. All the patients were then instructed to trigger a patient controlled analgesia (PCA) device for top-up doses of 0.25% bupivacaine with adrenaline 1 in 400,000 once they became aware of pain returning. This PCA device was preset to give on-demand injections of 12.5 mg with a lockout interval of 20 min, together with a continuous infusion rate of 10 mg.h-1. Pain was evaluated using four rating scales: QDSA, visual analogue scale (VAS), verbal rating scale (VRS) and behavioural scale (BS). Pain was measured at least four times: before analgesia (T0), 20 min after the initial injection (T20), before starting PCA (TRe), and immediately after delivery of the newborn (TEx). In addition, the level of anxiety was ranked at the beginning of labour with the Spielberger state trait anxiety inventory (STAI). In the 396 questionnaires completed by the patients, there was a significant correlation between the QDSA and the other scales (p less than or equal to 0.05), but at T0, BS was mostly correlated with the affective index of QDSA (p = 0.01), as well as with the STAI (p = 0.0001). At T20, in the group of women who had been given 0.5% bupivacaine initially, the decrease in QDSA score was significantly greater for the sensory index (p = 0.04); the first re-injection interval was longer than in the other group of women (p = 0.05). At TRe, the total QDSA score of all the patients was half that at T0, indicating the good sensitivity of this score. These results are in agreement with those reported by Melzack with the McGill pain questionnaire. The QDSA varies in the same direction as the other scales. On the other hand, the affective part of the score was only correlated with the level of anxiety and behaviour. The sensory part of this score was the only one to show a difference between the different initial doses given to the patients. The results obtained with this series of patients underline the value of a multidimensional assessment of labour pain.