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 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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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
Prophylactic i.m. ephedrine in bupivacaine spinal anaesthesia.
In a double-blind, placebo-controlled, randomized study, we have investigated the efficacy of i.m. ephedrine in 98 elderly patients undergoing hip arthroplasty under spinal anaesthesia with plain bupivacaine. Fifty patients received ephedrine 0.6 mg kg-1 body weight, deep in the paravertebral muscles immediately after injection of bupivacaine, and 48 received an equal volume of saline. ⋯ An increase in heart rate or systolic pressure of > or = 20% from baseline was found in two patients in the ephedrine group and in one patient in the placebo group. We conclude that ephedrine 0.6 mg kg-1 body weight administered in the paravertebral muscles immediately after plain bupivacaine spinal anaesthesia is a simple and effective means of reducing the incidence of hypotensive episodes in the elderly patient.
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Randomized Controlled Trial Clinical Trial
Tranexamic acid (Cyklokapron) reduces perioperative blood loss associated with total knee arthroplasty.
In this prospective, randomized, double-blind study, we have investigated the effect of an antifibrinolytic agent, tranexamic acid (Cyklokapron), on blood loss and transfusion requirements associated with total knee arthroplasty. Twenty-nine patients were allocated randomly to receive either tranexamic acid 15 mg kg-1 or an equal volume of placebo a few minutes before a tourniquet was deflated. Blood loss during surgery, in the recovery room and on the surgical ward was recorded, together with the number of units of blood transfused in hospital. ⋯ During the hospital stay the treatment group received 1.5 (1.3) units of blood compared with 3.3 (1.8) in the control group (P < 0.005). Two patients in the placebo group experienced a thrombotic complication compared with none in the treatment group. We conclude that tranexamic acid reduced perioperative blood loss and transfusion requirements associated with total knee arthroplasty.