Canadian journal of anaesthesia = Journal canadien d'anesthésie
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The anaesthetic management of two patients with uncontrolled hyperthyroidism requiring Caesarean section is described. The first patient was diagnosed as hyperthyroid during pregnancy but was resistant to medical management with propylthiouracil (PTU). At 38 weeks' gestation, after optimizing her heart rate with intravenous propranolol, she received an epidural anaesthetic for the Caesarean section. ⋯ Preoperative control of hyperthyroidism, bearing in mind pregnancy and time constraints, is essential. The use of PTU, propranolol, iodine, and glucocorticoids is described in the preparation of the parturient. Fetal and neonatal effects of these drugs are discussed.
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Randomized Controlled Trial Clinical Trial
Atropine-neostigmine mixture: a dose-response study.
The dose-response relationship and the doses of atropine required to prevent neostigmine from lowering heart rates below baseline in 50 per cent (ED50) and 95 percent (ED95) of patients after antagonism of pancuronium-induced neuromuscular blockade were determined in 70 patients with neostigmine-atropine mixtures. Neostigmine 0.04 mg.kg-1 (group A, n = 35) or 0.06 mg.kg-1 (group B, n = 35) was randomly mixed with one of seven doses of atropine (ranging from 0.014 to 0.04 mg.kg-1) in group A and from 0.02 to 0.04 mg.kg-1 in group B), with dose-response curves for atropine being constructed for both groups 5 and 10 min after injection of the mixture. These dose-response curves were found to be parallel in both groups. ⋯ The estimated ED50 doses of atropine in groups A and B at 5 min were 0.031 and 0.033 mg.kg-1 respectively, and at 10 min the ED50 doses were 0.037 and 0.037 mg.kg-1 respectively. The calculated ED95 doses of atropine in groups A and B at 5 min were 0.05 and 0.046 mg.kg-1, and at 10 min the ED95 doses were also similar, being 0.06 and 0.055 mg.kg-1 respectively. Under the conditions employed in this study it would seem that in order to prevent late reductions in heart rates, the appropriate doses of atropine when used with neostigmine should be greater than that commonly used.
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Comparative Study Clinical Trial Controlled Clinical Trial
Comparison of perioperative mental function after general anaesthesia and spinal anaesthesia with intravenous sedation.
This study compared the postoperative mental function in 44 elderly patients following general anaesthesia (GA) or spinal anaesthesia (SA) with sedation for transurethral resection of prostate. The Mini-Mental State (MMS) was done preoperatively and postoperatively at six hours, one day, three days, five days and one month. The geriatric mental status examination was performed preoperatively and one month after the anaesthetic. ⋯ In the GA group, the significant decrease in MMS score occurred at 6 h postoperatively (P less than 0.002) whereas in the SA group with sedation, MMS score also decreased significantly at 6 h (P less than 0.005). In conclusion, there was no significant difference in perioperative mental function between the general and spinal anaesthetic groups when supplemental IV sedation was given. In both groups, perioperative mental function decreased significantly at 6 h postoperatively.
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The haemodynamic responses to laryngoscopy and intubation after induction of anaesthesia with thiopentone alone or in combination with 1.5 mg.kg-1 lidocaine and/or 1.5 or 3.0 microgram.kg-1 fentanyl were measured in 150 patients over 64 years of age to determine whether lidocaine, fentanyl or both lidocaine and fentanyl attenuated the pressor response. Fentanyl reduced the rises in systolic, diastolic and mean arterial pressures, heart rate, and rate pressure product and lidocaine decreased the rises in arterial blood pressure and rate pressure product (P less than 0.05). Fentanyl decreased the incidence of marked fluctuations in haemodynamic variables, often seen in geriatric patients (P less than 0.05). ⋯ Fentanyl-treated patients had a higher incidence of hypotension (P less than 0.05). Respiratory depression developed in only one per cent of the fentanyl-treated patients. Both lidocaine and fentanyl are recommended adjuncts to induction of anaesthesia with thiopentone in geriatric patients.
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Case Reports
Failure of a lidocaine test dose to identify subdural placement of an epidural catheter.
We report the failure of a test dose of 3 ml lidocaine 1.5 per cent with 15 micrograms epinephrine to identify subdural placement of an epidural catheter in a parturient. Thirty-five minutes after injection of 13 ml lidocaine 1.5 per cent, intended to provide epidural analgesia, the patient developed an extensive sensory neural blockade. Some motor control was maintained and sympathetic block was incomplete. ⋯ Subdural injections are uncommon and unpredictable in their occurrence. Test doses do not consistently identify misplaced catheters. A negative response to a test dose does not guarantee that extensive neural blockade will not occur during epidural analgesia.