British journal of anaesthesia
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Clinical Trial Controlled Clinical Trial
Extradural pain relief in labour: bupivacaine sparing by extradural fentanyl is dose dependent.
The minimum local analgesic concentration (MLAC) of bupivacaine in labour is defined as the effective concentration in 50% of subjects (EC50). We have used the technique of double-blinded sequential allocation to quantify the bupivacaine sparing effect of the addition of four different doses of extradural fentanyl in 223 labouring women. There were five groups: (1) plain bupivacaine (control); (2) bupivacaine with fentanyl 1 microgram ml-1; (3) bupivacaine with fentanyl 2 micrograms ml-1; (4) bupivacaine with fentanyl 3 micrograms ml-1; and (5) bupivacaine with fentanyl 4 micrograms ml-1. ⋯ We observed a reduction in MLAC of 18%, 31% (P = 0.03%), 55% (P < 0.0001) and 72% (P < 0.0001) with fentanyl 1, 2, 3 and 4 micrograms ml-1, respectively, demonstrating a significant negative linear trend (P < 0.0001) with increasing fentanyl dose. The incidence of pruritus was increased significantly with fentanyl 4 micrograms ml-1 (P = 0.0015). Because of this, fentanyl 3 micrograms ml-1 may be the optimal dose when the aim is bupivacaine sparing extradural analgesia during labour.
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Comparative Study Clinical Trial Controlled Clinical Trial
Combined spinal-extradural anaesthesia for preterm and term caesarean section: is there a difference in local anaesthetic requirements?
In a non-blinded observational study, we have tested the null hypothesis that there is no difference in local anaesthetic requirements for subarachnoid anaesthesia between women presenting for Caesarean section at term or preterm (38-42 and 28-35 weeks' gestation, respectively). Using a combined spinal-extradural technique, 2.25 ml of 0.5% hyperbaric bupivacaine was given, in the sitting position, to 50 women presenting for Caesarean section. ⋯ All women in the term group developed adequate anaesthesia with the subarachnoid dose alone. Onset of anaesthesia was slower in the preterm group (median 15 vs 5 min) with a lower incidence of hypotension (P = 0.0005).
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Major surgery is still associated with undesirable sequelae such as pain, cardiopulmonary, infective and thromboembolic complications, cerebral dysfunction, nausea and gastrointestinal paralysis, fatigue and prolonged convalescence. The key pathogenic factor in postoperative morbidity, excluding failures of surgical and anaesthetic technique, is the surgical stress response with subsequent increased demands on organ function. ⋯ To understand postoperative morbidity it is therefore necessary to understand the pathophysiological role of the various components of the surgical stress response and to determine if modification of such responses may improve surgical outcome. While no single technique or drug regimen has been shown to eliminate postoperative morbidity and mortality, multimodal interventions may lead to a major reduction in the undesirable sequelae of surgical injury with improved recovery and reduction in postoperative morbidity and overall costs.
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Clinical Trial
Assessment of cardiovascular changes during laparoscopic hernia repair using oesophageal Doppler.
We have used an oesophageal Doppler to measure aortic blood flow velocity before, during and after induction of carbon dioxide pneumoperitoneum in 10 consecutive patients, mean age 58 yr, undergoing laparoscopic hernia repair. Derived values for stroke distance, minute distance and systemic vascular resistance showed considerable interpatient variation indicating unpredictable haemodynamic responses. ⋯ There was a corresponding increase in the index of systemic vascular resistance from 1092 (747) to 2079 (400) (P < 0.05) which persisted after deflation of the abdomen. Oesophageal Doppler can provide continuous online haemodynamic data with a rapid response to acute changes and may have a role in non-invasive haemodynamic monitoring during laparoscopic procedures in older patients with cardiovascular disease.