British journal of anaesthesia
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Randomized Controlled Trial Clinical Trial
Effect of ketanserin on intraoperative blood loss during total hip arthroplasty in elderly patients under general anaesthesia.
We have studied the effect of ketanserin, a selective serotonin S2-receptor antagonist, on surgical bleeding in a double-blind, placebo-controlled study in elderly patients undergoing total hip arthroplasty. One group of patients (n = 9) received ketanserin 10 mg i.v. followed by an infusion of 0.075 mg kg-1 h-1. The second group (n = 8) received placebo. ⋯ In the ketanserin group, mean arterial pressures tended to be less than in the placebo group. Reductions in central venous pressure were similar in both groups. There were no complications in relation to the use of ketanserin.
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Randomized Controlled Trial Clinical Trial
Influence of the lumbar interspace chosen for injection on the spread of hyperbaric 0.5% bupivacaine.
Forty patients undergoing elective Caesarean section were allocated randomly to receive hyperbaric 0.5% bupivacaine 2.5 ml at either the L2-3 (n = 20) or L4-5 (n = 20) interspace. Spinal injection was performed with a 29-gauge needle in 38 patients and a 25-gauge needle in two. ⋯ One case of post-dural puncture headache was recorded after use of a 29-gauge needle. Overall, the choice of lumbar interspace influenced the rate of onset of analgesia, but not the final dermatomal level (mean and range) of analgesia achieved.
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We have investigated 296 inpatients in a single-blind observer study to determine the incidence, degree and duration of hypoxaemia during anaesthesia. The clinical recognition of hypoxaemia, period of time until recognition and risk factors were studied. Oxygen saturation (Spo2) was monitored continuously with a pulse oximeter (Ohmeda, model 3700). ⋯ After intervention a mean time delay of 57 s was recorded until Spo2 exceeded 90%. Utilizing a stepwise multiple logistic regression analysis, we found that risk factors associated with a greater incidence of hypoxaemia were patient age (P less than 0.005) and anaesthetic technique (P less than 0.00001). We conclude that hypoxaemic episodes in our operating rooms are common during anaesthesia and suggest preoxygenation in all patients in addition to administration of supplementary oxygen during arousal from anaesthesia and during transfer to the recovery room.
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We have studied the effects of anaesthesia on atelectasis formation and gas exchange in 45 patients of both sexes, smokers and nonsmokers, aged 23-69 yr. None of the patients showed clinical signs of pulmonary disease, and preoperative spirometry was normal. In the awake patient, partial pressure of arterial oxygen (PaO2) decreased with increasing age (P less than 0.001) and the alveolar-arterial oxygen partial pressure difference (PAO2-PaO2) increased with age (P less than 0.001). ⋯ Atelectasis and shunt did not increase significantly with age, whereas log SD Q and perfusion of regions with low VA/Q ratios did (r = 0.55, P less than 0.001 and r = 0.35, P less than 0.05, respectively). Awake, the major determinant of PaO2 was perfusion of regions of low VA/Q ratios, which increased with age. During anaesthesia shunt influenced PaO2 most, low VA/Q being a secondary factor which, however, was increasingly important with increasing age, thus explaining the well-known age-dependent deterioration of arterial oxygenation during anaesthesia.
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Randomized Controlled Trial Comparative Study Clinical Trial
Reversal of benzodiazepine sedation with the antagonist flumazenil.
The effectiveness of the benzodiazepine antagonist, flumazenil, was evaluated in a randomized double-blind clinical study in which diazepam 0.2 mg kg-1 or midazolam 0.1 mg kg-1 was used for i.v. sedation. We studied 120 day-case patients undergoing gastroscopy and treated with either flumazenil 0.1-2 mg or placebo after the procedure. Psychometric assessment of four aspects of recovery over a 3-h period showed that flumazenil attenuated the sedative effects of the benzodiazepines, but did not antagonize the sedation completely. ⋯ Flumazenil did not attenuate the subjective experience of sedation as measured by visual analogue scales. These results indicate that sedation is multidimensional, differentially affecting the hierarchy of cognitive functions. In day-cases, antagonism of benzodiazepine sedation with flumazenil would not hasten the safe discharge of patients.