British journal of anaesthesia
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We have developed a computer program that estimates venous admixture (intra-pulmonary shunt) from four measurements: haemoglobin concentration, end-tidal carbon dioxide tension (PE'CO2), fractional inspired oxygen concentration (FIO2) and pulse oximetry (SpO2). The formula was tested on patients in an intensive therapy unit by using it to estimate shunt while it was measured simultaneously by a standard, invasive method. ⋯ The limits of agreement were then +/- 16% shunt overall (+/- 13% within patients). When SaO2 was used instead of SpO2, the limits were +/- 11% (+/- 8% within patients).
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Randomized Controlled Trial Comparative Study Clinical Trial
Extradural anaesthesia for caesarean section: a double-blind comparison of 0.5% ropivacaine with 0.5% bupivacaine.
Seventy-three parturients for elective Caesarean section were allocated randomly to receive extradural block with 20 ml of either 0.5% ropivacaine or 0.5% bupivacaine. If the block did not reach T6 within 30 min, another 5 ml of solution was given. If needed, a further 5 ml was given 45 min after the main dose. ⋯ There was no significant difference between the groups in the profile of sensory block produced. There was no significant difference in the time of onset, or intensity of motor block between the groups but the duration of motor block was significantly shorter in the ropivacaine group. There was no significant difference in neonatal outcome, as assessed by Apgar score, umbilical cord blood-gas tensions at delivery or the neurological and adaptive capacity score 2 and 24 h after delivery.
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Randomized Controlled Trial Clinical Trial
Intra-vas deferens bupivacaine for prevention of acute pain and chronic discomfort after vasectomy.
We have studied the use of intra-vas deferens local anaesthesia in 70 patients undergoing vasectomy as day-case patients. Patients were allocated randomly to either a control or treatment group. In the treatment group, 0.5% bupivacaine 1 ml or 0.9% saline 1 ml was injected into the lumen of the right or left vas deferens in a randomized blinded design. ⋯ One year after the procedure a second questionnaire was sent out asking about the presence or absence of chronic testicular discomfort, its duration and any surgical intervention required to relieve it. There were no differences between the control group and the saline side of the treatment group in VAS scores on both day 1 and day 7 after operation or in the incidence and duration of chronic testicular discomfort (mean 30 (SD 53) and 34 (50) days, respectively). The VAS scores were, however, significantly less (P < 0.005) and testicular discomfort was absent on the bupivacaine-treated side.
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Infraorbital nerve block in neonates is not well described although it has been suggested that bilateral infraorbital nerve block is the local analgesic technique of choice for early repair of cleft lip. The purpose of this study was to determine the location of the infraorbital nerve in neonatal cadavers and to identify clinically useful landmarks. Thirty infraorbital nerves were identified in 15 neonatal cadavers with a mean weight of 2.85 (SD 0.32) kg (range 2.45-3.5 kg) via an upper buccal sulcus incision. ⋯ A line drawn from the angle of the mouth to the midpoint of the palpebral fissure measured 30.6 (1.9) mm (left) and 30.7 (1.8) mm (right). The nerve was situated approximately halfway along this line at a point 15.5 (1.5) mm (left) and 15.2 (1.4) mm (right) from the angle of the mouth. These measurements were used to perform bilateral infraorbital nerve blocks in four neonates undergoing cleft lip surgery under general anaesthesia, thereby providing analgesia with minimal risk of respiratory depression.