Patient-controlled epidural analgesia in labour: varying bolus dose and lockout interval.

This double-blind prospective study was designed to determine the best dose variables for patient-controlled epidural analgesia (PCEA) and to compare bolus-only PCEA with continuous infusion epidural analgesia (CIEA) during the first stage of labour. Five groups of parturients self-administered 0.125% bupivacaine with 1:400,000 epinephrine and fentanyl 2.5 micrograms.ml-1 using PCA pumps programmed as follows: Group A, 2 ml bolus/10 min lockout interval (LI); Group B, 3 ml bolus/15 min LI; Group C, 4 ml bolus/20 min LI; Group D, 6 ml bolus/30 min LI; Group E, 8 ml.hr-1 continuous infusion. Hourly assessments included: VAS scores for pain and satisfaction, sensory and motor block, bupivacaine and fentanyl consumption. Blood samples were collected at birth for maternal and fetal fentanyl concentrations. Data from 68 patients showed no differences among groups in pain relief or maternal satisfaction. Most patients received excellent analgesia and those requiring extra epidural supplements were evenly distributed across groups. There was higher consumption of bupivacaine and fentanyl in Group E than in any of the other four groups: bupivacaine mg.hr-1, mean (SD), 9.4 (2.7) in Group E vs 5.2 (1.7) in Groups A-D inclusive (P < 0.0001); fentanyl microgram.hr-1, 19.6 (4.6) in group E vs 12.6 (7.5) in Groups A-D inclusive (P < 0.05). Motor block was minimal, whereas sensory levels were higher at the 3- and 4-hour assessments in Groups D and E than in all other groups (P < 0.05). Plasma fentanyl concentrations were < 0.5 ng.ml-1 in all samples and no sequelae from fentanyl were observed, apart from mild pruritus.(ABSTRACT TRUNCATED AT 250 WORDS)

Epidural anaesthesia for caesarean section: comparison of two injection techniques.

Two techniques of injection for epidural anaesthesia for Caesarean sections were studied. Forty-five patients were randomly divided into two groups. Patients in Group I received 20 ml of lidocaine two per cent with epinephrine via the needle at a rate of 5 ml.30 sec-1 after a 3 ml test dose. Patients in Group II received the same dose of the same solution in increments of 5 ml injected through a catheter after a 3 ml test-dose. Each increment was injected in one minute with a delay of two minutes between injections. Top-up doses were given in both groups to obtain a T4 sensory level. There was no difference between the two groups in the quality of sensory block before delivery. However, the quality was significantly better in Group II after delivery (P = 0.02). The incidence of hypotension was 52.2 per cent in Group I and 13.6 per cent in Group II (P = 0.014). There was no significant difference in maternal and umbilical venous lidocaine concentrations. We conclude that injection in fractional doses is a safer and more efficient technique for epidural anaesthesia for Caesarean section.