Comparison of continuous and intermittent administration of extradural bupivacaine for analgesia after lower abdominal surgery

Abstract

We have compared intermittent bolus and continuous infusion of extradural local anaesthetic for pain relief in a randomized, double-blind study of 48 patients who underwent major abdominal gynaecological surgery. Each patient received 5 ml of 0.375% bupivacaine hourly, either as a bolus over 5 min or as a constant infusion. Patients who received the intermittent administration technique maintained a more extensive sensory block, reported marginally better analgesia and had a lower requirement for rescue medication. The intermittent bolus technique was not associated with an increase in side effects.

Intermittent vs continuous administration of epidural ropivacaine with fentanyl for analgesia during labour †

“…Regression of sensory block over time, need for regular rescue medication and excessive motor block are all well recognized complications of epidural infusions. [1][2][3][4][5] Support for the greater efficacy of bolus injection of local anaesthetics comes from both cadaveric dissection and clinical study. Cryomicrotome sectioning has shown more uniform spread of liquid in the epidural space, through the intervertebral foraminae, and along nerve sheaths when using large volumes of injectate, and a high injection pressure.…”

“…Using data from a previous study comparing regular intermittent bolus to continuous infusion for administration of epidural drug, 2 we calculated that a sample size of 40 patients (20 per group) would give the study a power of >0.9 to detect a statistically significant difference in visual analogue pain scores. This calculation was based on mean (SD) visual analogue pain scores at 4 h of 36 (20) mm in the continuous group and 12 (7) mm in the intermittent group.…”

“…However, more sophisticated devices are now available and have allowed re-evaluation of programmed bolus administration at regular intervals, with confirmation of the earlier observation in postoperative patients. 2 Constant infusion tends to result in progressive regression in the block, with resultant failure of pain control and an increase in anaesthetic workload. 3 4 This may be a particular problem if the analgesic requirements are increasing, as is the case during labour, so a randomized, double-blind study was devised to compare regular intermittent bolus administration with continuous infusion in patients receiving epidural analgesia during labour.…”

Automated regular boluses for epidural analgesia: a comparison with continuous infusion

“…Indeed, the outcome of an earlier study assessing these two different modes of epidural drug delivery in patients after lower abdominal surgery agreed with the findings of our study. 5 Previous studies have shown that quality of labor analgesia was improved when multi-orificed catheters were used instead of single orifice catheters. 6 A differential flow of local anesthetic from the orifices of a multi-orificed catheter occurs with a continuous infusion.…”

“…Institutions where labor epidural analgesia is maintained by manual analgesic boluses (usually undertaken by nursing staff) will inevitably increase their workload, especially if epidural boluses are to be administered regularly. 5,11 The use of an automated regular bolusing device would, in principle, be a welcome improvement. Even when similar doses were used, regular boluses were associated with a longer duration of labor analgesia than continuous epidural infusion of local anesthetic.…”