British journal of anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Levobupivacaine vs bupivacaine as infiltration anaesthesia in inguinal herniorrhaphy.
We have compared the anaesthetic and analgesic efficacy of levobupivacaine with that of racemic bupivacaine in 66 male patients undergoing ambulatory primary inguinal herniorrhaphy. Patients were allocated randomly in a double-blind manner to local infiltration anaesthesia (0.25% w/v 50 ml) with either racemic bupivacaine (n = 33) or levobupivacaine (n = 33). Scores for intraoperative pain and satisfaction with anaesthesia were recorded, together with perception of postoperative pain and need for supplementary postoperative analgesic medications in the first 48 h after operation. ⋯ Time averaged postoperative pain scores (48 h) were 8 (levobupivacaine) and 10 (bupivacaine) in the supine position, 13 (levobupivacaine) and 12 (bupivacaine) while rising from the supine position to sitting, and 9 (levobupivacaine) and 13 (bupivacaine) while walking (VAS; 100 mm = worst pain imaginable) (ns). There was no difference in the use of peroral postoperative analgesics between the two groups. We conclude that racemic bupivacaine and its S-enantiomer levobupivacaine had similar efficacy when used as local infiltration anaesthesia in inguinal herniorrhaphy.
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Randomized Controlled Trial Comparative Study Clinical Trial
Comparison of intrathecal and epidural diamorphine for elective caesarean section using a combined spinal-epidural technique.
To assess calculated equivalent doses of intrathecal and epidural opioids for elective Caesarean section in terms of quality and duration of analgesia, and incidence of side effects, we have compared 50 patients, allocated randomly to one of two groups to receive either diamorphine 0.25 mg intrathecally (group 1) or 5 mg epidurally (group 2), in addition to intrathecal bupivacaine 10 mg, using a combined spinal-epidural technique. There was no significant difference in duration of analgesia between groups (group 1 mean 14.6 (SD 5.9) h, group 2 14.2 (6.5) h; mean difference 0.8 h; 95% Cl -2.8-4.5; P = 0.65) or quality of analgesia (VAPS and VRS scores). The degree of pruritus was similar in both groups (80-88%) but the incidence of postoperative nausea and vomiting was significantly higher in the epidural group (24% vs 4%; P < 0.05). Intrathecal diamorphine 0.25 mg produced the same duration and quality of postoperative analgesia as epidural diamorphine 5 mg for elective Caesarean section but with significantly less nausea and vomiting.
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Randomized Controlled Trial Comparative Study Clinical Trial
Respiratory effects of low-dose bupivacaine interscalene block.
In this double-blind study, interscalene brachial plexus (ISBP) block was performed in 11 volunteers using 10 ml of either 0.25% (n = 6) or 0.5% (n = 5) bupivacaine with epinephrine 1:200,000. Diaphragmatic excursion, respiratory function and neural function were assessed for 90 min. ⋯ Sensory anaesthesia in the upper limb was found consistently in both groups, although biceps paralysis occurred earlier after 0.5% bupivacaine. We conclude that ISBP block using 10 ml of 0.25% bupivacaine provided upper limb anaesthesia to pinprick in C5-6 dermatomes with only occasional interference with respiratory function.
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We have examined the response of lumbar dorsal horn cells to a noxious mechanical stimulus during differential delivery of isoflurane to the brain and spinal cord of goats. We hypothesized that isoflurane, acting in the brain, would depress dorsal horn neuronal responses to a noxious mechanical stimulus applied to the hindlimb. Eight goats were anaesthetized with isoflurane and neck dissections performed which allowed cranial bypass. ⋯ When the torso isoflurane concentration was 1.3%, decreasing cranial isoflurane from 1.3% to 0.3% did not significantly affect dorsal horn responses (from mean 325 (SD 262) to 379 (412) impulses min-1; P < 0.05). However, when torso isoflurane was 0.8%, decreasing cranial isoflurane from 1.3% to 0.3% increased mean evoked dorsal horn activity by 42% (388 (359) to 551 (452) impulses min-1; P < 0.05). These data suggest that the major effect of isoflurane on dorsal horn responses to noxious stimuli is direct, but there is an indirect effect occurring via descending projections from supraspinal regions.
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Systolic pressure variation (SPV) and its dDown component have been shown to be sensitive factors in estimating intravascular volume in patients undergoing mechanical ventilation. In this study, ventilation-induced changes in pulse oximeter plethysmographic waveform were evaluated after removal and after reinfusion of 10% estimated blood volume. The plethysmographic waveform variation (SPVplet) was measured as the difference between maximal and minimal peaks of waveform during the ventilatory cycle, and expressed as a percentage of the signal amplitude during apnoea. dUp(plet) and dDown(plet) were measured as the distance between the apnoeic plateau and the maximal or minimal plethysmographic systolic waveform, respectively. ⋯ A 10% decrease in blood volume increased SPVplet from mean 17.0 (SD 11.8)% to 31.6 (28.0)% (P = 0.005) and dDown(plet) from 8.7 (5.1)% to 20.5 (12.9)% (P = 0.0005) compared with baseline. Changes in plethysmographic waveform correlated with changes in arterial SPV and dDown (r = 0.85; P = 0.0009). In the absence of invasive arterial pressure monitoring, ventilation-induced waveform variability of the plethysmographic signal measured from pulse oximetry is a useful tool in the detection of mild hypovolaemia.