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Can immediate opioid requirements in the post-anaesthesia care unit be used to determine analgesic requirements on the ward?


The aim of this prospective study was to evaluate the efficacy of two dosage regimens of (im) morphine calculated from an initial (iv) titrated dose in the early postoperative period. Seventy ASA I–III patients who underwent general anaesthesia (GA) (n = 58), regional anaesthesia (RA) (n = 10) or GA + RA (n = 2) for orthopaedic (n = 54), urological (n = 11) or abdominal surgery (n = 5) received iv titrated morphine in the post-anaesthesia care unit (PACU). Titration consisted of 3 mg morphine iv every ten minutes until patients had a visual analogue pain scale (VAS) <3, without marked sedation. Seventeen patients did not complain at all or had good analgesia with an initial iv dose ≤6 mg of morphine followed by paracetamol only. Patients who needed more than 6 mg iv morphine were randomly assigned to a “high-dose” or a “low-dose” group and received a systematic im morphine regimen calculated from the initial titrated dose. Pain was assessed by VAS before each im injection and the next morning. One patient had respiratory depression and one marked sedation in the PACU. These patients were excluded from the rest of the study. Only 16 patients had a VAS >3 at least once during the study period and only three needed rescue analgesia which was available on request. We conclude that a systematic im morphine regimen adapted from an initial iv titration in the PACU provides efficacious and relatively inexpensive postoperative analgesia, applicable to a great majority of patients.


Ce travail prospectif avait pour objectif d’évaluer l’efficacité de deux posologies de morphine calculées à partir d’un titrage iv à la période postopératoire immédiate. Chez 70 patients ASA I–III soumis à une chirurgie orthopédique (n = 54), urologique (n = 11) ou abdominale (n = 5) sous anesthésie générale (n = 58), loco-régionale (n = 10) ou les deux (n = 2), on a titré la morphine iv à l’unité des soins postopératoires. Le titrage a consisté à injecter 3 mg de morphine iv toutes les dix minutes jusqu’à l’obtention d’un score <3 sur une échelle visuelle analogue (EVA) sans sédation importante. Dix-sept patients ne se sont plaints d’aucune douleur ou ont rapporté une bonne analgésie avec la dose initiale de morphine ≤6 mg suivie uniquement de paracétamol. Les patients qui ont eu besoin de plus de 6 mg de morphine iv ont été assignés au hasard à un groupe «forte dose» ou à un groupe «faible dose». Ils ont reçu de la morphine im de façon systématique à la posologie calculée selon la dose initiale. La douleur était évaluée sur l’EVA avant chaque injection im et le lendemain matin. A la salle de réveil, un patient a présenté une dépression respiratoire précoce et un autre une sédation importante. Ces patients ont alors été exclus de l’étude. Seuls 16 patients ont révélé un EVA >3 au moins une fois pendant la période de l’étude et seulement trois ont demandé une analgésie supplémentaire. Nous pouvons conclure que la morphine im systématique administrée selon un titrage initial iv procure une analgésie efficace et peu coûteuse, applicable à la majorité des patients.


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Correspondence to Jean Xavier Mazoit.

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This work was supported in part by a grant from INSERM # 91 CN05.

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Butscher, K., Mazoit, J.X. & Samii, K. Can immediate opioid requirements in the post-anaesthesia care unit be used to determine analgesic requirements on the ward?. Can J Anaesth 42, 461–466 (1995).

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Key words

  • analgesia: postoperative pain
  • analgesics: morphine, postoperative, opioids, morphine