British journal of anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Effects of fenoterol and ipratropium on respiratory resistance of asthmatics after tracheal intubation.
We have studied the effects of a beta-agonist, fenoterol, and a cholinergic antagonist, ipratropium, on post-intubation total respiratory system resistance (Rrs) in asthmatics who developed increased Rrs after tracheal intubation. Sixteen stable asthmatics in whom Rrs increased after intubation were allocated randomly to receive either 10 puffs of fenoterol (group F) or 10 puffs of ipratropium (group IB) via a metered dose inhaler 5 min after intubation. Anaesthesia was induced and maintained with propofol i.v. ⋯ At all times after treatment, patients in the fenoterol group had significantly lower Rrs values than those in the ipratropium group. We conclude that increased Rrs after tracheal intubation in asthmatics can be reduced effectively by treatment with fenoterol. A secondary finding of our study was that even after induction of anaesthesia with propofol, patients with a history of asthma may develop high Rrs.
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Randomized Controlled Trial Clinical Trial
S(+)-ketamine for caudal block in paediatric anaesthesia.
We have evaluated the intra- and postoperative analgesic efficacy of preservative-free S(+)-ketamine compared with bupivacaine for caudal block in paediatric hernia repair. After induction of general anaesthesia, 49 children undergoing hernia repair were given a caudal injection (0.75 ml kg-1) of S(+)-ketamine 0.5 mg kg-1 (group K1), S(+)-ketamine 1.0 mg kg-1 (group K2) or 0.25% bupivacaine with epinephrine 1:200,000 (group B). No additional analgesic drugs were required during operation in any of the groups. ⋯ Groups B and K2 required less analgesics in the postoperative period compared with group K1 (30% and 33% vs 72%; P < 0.05). Postoperative sedation scores were comparable between the three groups. We conclude that S(+)-ketamine 1.0 mg kg-1 for caudal block in children produced surgical and postoperative analgesia equivalent to that of bupivacaine.
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Randomized Controlled Trial Clinical Trial
Oral preanaesthetic medication for children: double-blind randomized study of a combination of midazolam and ketamine vs midazolam or ketamine alone.
Anxiolysis and sedation with oral midazolam are common practice in paediatric anaesthesia. However, good or excellent results are seen in only 50-80% of cases. For this reason, we investigated if addition of a low dose of oral ketamine (MIKE: ketamine 3 mg kg-1, midazolam 0.5 mg kg-1) resulted in better premedication compared with oral midazolam 0.5 mg kg-1 or ketamine 6 mg kg-1 alone, in a prospective, randomized, double-blind study. ⋯ In summary, significantly better anxiolysis and separation were observed with a combination of ketamine and midazolam, even in awake children (sedation was not successful according to the preset criteria), than with midazolam or ketamine alone. Duration of action and side effects of the combination were similar to those of midazolam. The combination of both drugs in strawberry flavoured glucose syrup (pH 4.5 approximately) is chemically stable for 8 weeks.
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To understand the sequential response of the autonomic nervous system to pregnancy, we studied heart rate variability in 23 first trimester, 23 second trimester and 21 third trimester pregnant women. Twenty non-pregnant women were recruited as controls. Time and frequency domain measures of heart rate variability in three recumbent positions were compared. ⋯ When the position was changed from the supine to the right lateral decubitus, the percentage change in normalized high-frequency power correlated significantly and negatively with normalized high-frequency power in the supine position in non-pregnant controls (r = -0.56, P = 0.01) and in pregnant women in the first (r = -0.44, P = 0.034), second (r = -0.68, P < 0.001) and third (r = -0.68, P < 0.001) trimesters. These results indicate that autonomic nervous activity shifted towards a lower sympathetic and higher vagal modulation in the first trimester, and changed towards a higher sympathetic and lower vagal modulation in the third trimester as gestational age increased. The balance between the haemodynamic changes of pregnancy and aortocaval compression caused by the enlarging gravid uterus may be responsible for the biphasic changes in autonomic nervous activity during pregnancy.