Patient-controlled analgesia

In appropriately selected patients, PCA safely provides analgesia superior to that obtained with traditional IM prn opioid administration; however, to date, no compelling evidence shows that PCA is associated with a reduction in morbidity or a more rapid recovery. PCA is deceptively easy to prescribe; however, to use it effectively and safely requires experience, frequent patient assessment, and a skilled and knowledgeable nursing staff.

Continuous epidural ropivacaine 0.2% for analgesia after lower abdominal surgery

The purpose of this study was to determine whether a lumbar epidural infusion of ropivacaine 0.2% would provide effective analgesia with an acceptably low incidence of motor blockade and side effects after lower abdominal surgery. After combined general and epidural anesthesia and surgery, 125 patients were randomly assigned to receive either saline or ropivacaine 0.2% at a rate of 6, 8, 10, 12, or 14 mL/h (Groups R6, R8, R10, R12, and R14, respectively) for 21 h. Supplemental analgesia, if required, was provided with intravenous patient-controlled analgesia with morphine. Data were collected at 4, 8, and 21 h, and included morphine consumption, pain scores at rest and with coughing, motor and sensory block, and adverse events. Cumulative morphine consumption was less in Groups R10, R12, and R14 compared with the saline group. At 4 h analgesia was better among patients receiving ropivacaine, but at 21 h pain scores were identical. Sensory blockade at 8 and 21 h was greater in the ropivacaine groups compared with the saline group. Approximately 30% of R8, R10, and R12 patients, and 63% of R14 patients had demonstrable motor block of the lower limbs at 21 hours. We conclude that lumbar epidural ropivacaine 0.2% reduces parenteral morphine requirements but has little effect on pain scores and may be associated with motor blockade.

Patient-controlled epidural analgesia after thoracotomy: a comparison of meperidine with and without bupivacaine

The purpose of this study was to compare meperidine to meperidine with bupivacaine when used for patient-controlled epidural analgesia (PCEA) after thoracotomy. For 3 days after thoracotomy patients received thoracic PCEA with meperidine 0.1% plain or with added bupivacaine 0.1% or 0.01%. No background infusion was used. All patients received indomethacin postoperatively for the duration of the study. Patients were assessed with respect to meperidine consumption, analgesia, and side effects. Sixty-six patients participated. Patients in all three groups obtained effective analgesia with median meperidine consumption of 5-6 mg/h. There were no significant differences between groups in meperidine consumption or pain scores at rest or with coughing. The addition of bupivacaine 0.1% reduced the incidence of pruritus (P = 0.036), but 5 of 23 patients in this group were with-drawn from the study because of significant hypotension, oliguria, and/or motor or sensory block (P = 0.006). We conclude that the addition of bupivacaine 0.1% or 0.01% to thoracic PCEA meperidine 0.1% does not affect meperidine requirements or analgesia after thoracotomy. The addition of bupivacaine 0.1% may reduce pruritus, but is associated with signs of excessive sensory, motor, or autonomic blockade in a significant number of patients.

Continuous intravenous administration of ketorolac reduces pain and morphine consumption after total hip or knee arthroplasty

The purpose of this study was to determine the analgesic efficacy, opioid-sparing effect, and tolerability of ketorolac administered as an intravenous (i.v.) bolus followed by a continuous infusion after total hip or knee arthroplasty. After general anesthesia, patients received either placebo or ketorolac 30 mg i.v. as a bolus over 15-30 s followed by a continuous i.v. infusion of ketorolac 5 mg/h for 24 h. All patients received patient-controlled i.v. morphine with no background infusion. Patients were assessed at 2, 4, 6, and 24 postoperatively with respect to analgesia, morphine consumption, side effects, and blood loss. Patients receiving ketorolac reported were less sedated and required fewer antiemetics. There was no difference in blood loss. Patients receiving ketorolac reported better analgesia and used less morphine (35% for hips and 44% for knees) than those receiving placebo.

Respiratory depression associated with patient-controlled analgesia: a review of eight cases

Patient-controlled iv delivery of opioids for postoperative pain management is a popular alternative to the traditional im route of administration. However, occasional patients receiving opioids in this manner develop severe respiratory depression. The purpose of this paper is to determine the incidence of, and factors contributing to, the development of this complication. To do this, the Office of Medical Quality Improvement retrospectively searched for reports of respiratory depression in a database compiled from the charts of approximately 1600 patients who had received PCA at the University of Alberta Hospitals in 1992. Eight cases of serious respiratory depression were detected. Factors associated with the occurrence of respiratory depression included the concurrent use of a background infusion, advanced age, concomitant administration of sedative/hypnotic medications, and pre-existing sleep apnoea syndrome. No cases were attributed to operator error or equipment malfunction. In conclusion, the risk of respiratory depression with patient-controlled opioid administration is similar to that observed when opioids are delivered by the traditional im or spinal routes. The safe and effective use of patient-controlled analgesia depends upon knowledgeable medical and nursing staff, clearly defined nursing policy and procedures, and frequent patient follow-up.

A comparison of the analgesic and respiratory effects of epidural nalbuphine or morphine in postthoracotomy patients

This randomized, double-blind study compared the analgesic and respiratory effects of lumbar epidural morphine 5 mg, nalbuphine 10 mg, and nalbuphine 20 mg in repeated doses in patients after thoracotomy; the first dose was administered intraoperatively. Pre-and postoperative monitoring included continuous pulse oximetry, respiratory inductance plethysmography, and repeated arterial blood gas analysis. Postoperatively, visual analogue pain scores, somnolence scores, respiratory rate, and arterial blood gases were determined for 16 h. Preoperatively, episodes of apnea were common during sleep but were not associated with low hemoglobin oxygen saturation or increased arterial carbon dioxide tension (PaCO2). During sleep, some otherwise normal patients had increased PaCO2, and 2 of 15 patients had episodes of hemoglobin oxygen saturation of less than 90%. Postoperatively, 1 and 2 h after arrival in the recovery room, patients who received morphine had lower pain scores than did those who received nalbuphine 10 or 20 mg (P less than 0.05). All 6 patients who received morphine had satisfactory analgesia. Two of 4 patients who received nalbuphine 10 mg and all 5 who received nalbuphine 20 mg were withdrawn from the study because of inadequate analgesia (morphine vs. nalbuphine 10 mg, not significant; morphine vs. nalbuphine 20 mg, P less than 0.01). Two patients who received morphine had persistently increased PaCO2 postoperatively. Two patients who received morphine had episodes of apnea and slow respiratory rate, which were most frequent 6 h after arrival in the recovery room. We conclude that lumbar epidural nalbuphine does not provide adequate analgesia after thoracotomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Respiratory depression and spinal opioids

Administration of epidural and intrathecal opioids may provide excellent postoperative analgesia, but a minority of patients will suffer dangerous respiratory depression. This review discusses the detection and measurement of respiratory depression and summarizes the relevant literature as it pertains to epidural and intrathecal opioid administration. The respiratory depressant effects and pharmacokinetics of spinal opioids are reviewed. The clinical implications and areas of future investigation are discussed.