HYDROMORPHONE PATIENT-CONTROLLED ANALGESIA (PCA) AFTER CORONARY-ARTERY BYPASS-SURGERY

We conducted a study to compare the effectiveness of patient-controlle d analgesia (PCA) technique to conventional analgesic therapy (CAT) af ter coronary artery bypass graft (CABG). The PCA group received hydrom orphone 0.1 mg.hr(-1) basal infusion and bolus doses of 0.2 mg Q 5 min (maximum 1.2 mg.hr(-1)) while the CAT group received morphine 2.5 mg iv Q 30 min pm until extubation followed by pm meperidine 1 mg.kg(-1) im Q 4 hr or acetaminophen 325 mg with codeine 30 mg po (1 or 2 tablet s) when oral intake was possible. The degree of pain was assessed usin g a Visual Analogue Scale (VAS) starting after extubation and every 6- 8 hr for the next 60 hr. Holter monitoring was initiated one hour afte r patient arrival in the Intensive Care Unit (ICU) and continued for 7 2 hr. Other measured variables were pulmonary function, sedation, side effects and total opioid requirements. Results show that the day-to-d ay VAS pain score decreased in the PCA group (P < 0.001) while it rema ined unchanged in CAT patients. The PCA patients had lower VAS pain sc ores at extubation (P < 0.05). During the third postoperative day, the PCA group had a lower YRS pain score, a lower incidence of severe pai n defined as a score > 5 on the VAS scale, and a reduced incidence of myocardial ischaemia (P < 0.01). However there was no difference in th e duration severity area under the curve (AUC), or heart rate during i schaemic events. Postoperative pulmonary function was abnormal in both groups (NS) with minimal recovery by the fourth day Opioid requiremen ts, incidence of side effects and the degree of sedation Mare similar. We conclude that the PCA technique for analgesia provided slightly be tter results. The finding of a reduced incidence of myocardial ischaem ia in the PCA group warrants further clinical investigation.