Clinical aspects of continuous epidural blockade for postoperative pain relief

Urinary function during epidural analgesia with methadone and morphine in post-cesarean section patients

Urinary function was assessed in 120 women after cesarean section under epidural anesthesia. Postoperative analgesia was obtained by means of epidurally administered methadone (40 patients) or morphine (40 patients). In the remaining 40 women, no narcotic drugs were given and postoperative pain was treated with intramuscular or oral non-opiate analgesics and sedatives. Both methadone and morphine provided potent postoperative pain relief. Following epidural methadone, mean urine volumes of the first two postoperative voidings were increased (543 +/- 38 ml and 571 +/- 31 ml) as compared with those after epidural morphine (219 +/- 25 ml and 218 +/- 18 ml) and with those of patients receiving non-opiate analgesics (319 +/- 28 ml and 414 +/- 30 ml). The mean time interval between the end of surgery and first voiding following methadone analgesia was shorter (336 +/- 27 min) than after morphine (582 +/- 18 min) or after non-opiate (448 +/- 28 min) analgesic drugs. Difficulty in micturition and the need for bladder catheterization were also decreased in the group with epidural methadone (2.5%) in comparison with the groups receiving morphine (57.5%) or non-opiate analgesic medicaments (12.5%). The use of epidural methadone for postoperative pain relief is advocated, both in view of its analgesic potency and of the low incidence of urinary disturbances.

Epidural analgesia following thoracic surgery. A review of two years' experience

The use of thoracic epidurals for postoperative pain relief in 58 patients following thoracic surgery is reviewed. Epidural catheters were inserted at the end of the operative procedure and it was planned that analgesia was to be maintained with a continuous infusion of bupivacaine. In those patients with evidence of successful neurological blockade there was a high incidence of adverse effects. Hypotension occurred in nearly 80% of patients and inadequate analgesia necessitating intramuscular opiates in 30%. The results suggest that the method adopted is unsuitable for some patients who have undergone major pulmonary surgery, although it has proved a useful adjuvant for pain relief in patients who have had other intrathoracic operations.

Postoperative pain prevention by continuous epidural infusion. A study of the clinical effects and the plasma concentrations obtained

A method for postoperative pain prevention is described using epidural bupivacaine infused by means of a variable rate peristaltic pump. High plasma concentrations of bupivacaine were found but no serious signs of bupivacaine toxicity were observed and the method proved satisfactory in practice. Theoretical and practical considerations and aspects of clinical management are discussed.

Thoracic epidural analgesia-II: prolongation in the early postoperative period by continuous injection of 1.0% bupivacaine

Sixteen patients were given thoracic epidural analgesia at the T5-T6 level with 2 ml of 1.0% bupivacaine solution plain for pain relief after upper abdominal surgery. In 13 cases the analgesia was prolonged by continuous injection of 1.0% bupivacaine for 24 or 48 h. Onset time and segmental spread of the analgesia are presented as well as segmental spread, intensity of the blockade, and peak expiratory flow rates during prolongation. Signs of tachyphylaxis were noticed, and also signs of accumulation of bupivacaine in plasma. A high incidence of urinary retention occurred. The method is not considered to be ideal for pain relief after upper abdominal surgery.

Thoracic epidural analgesia I-a double-blind study between bupivacaine and etidocaine

A double-blind comparison was made in 40 patients undergoing thoracic epidural analgesia with either bupivacaine 0.5% or etidocaine 1.0%, both with adrenaline 5 mug/ml. All patients were undergoing elective upper abdominal surgery. They were studied both pre- and postoperatively. The parameters measured were: onset time, segmental spread and duration of analgesia; and also systolic blood pressure, heart rate and peak expiratory flow rate. In respect of these parameters, no major differences were found between the two solutions under the conditions of the study. The overall results, however, differ in many respects to those found when these agents are used in lumbar epidural analgesia.