Canadian Anaesthetists' Society journal
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Comparative Study
Neuromuscular blockade for rapid tracheal intubation in children: comparison of succinylcholine and pancuronium.
To compare the effectiveness of succinylcholine and pancuronium for rapid intubation in children, 49 healthy children ages two to eight years were studied. After induction of anaesthesia with thiopentone and atropine, and administration of droperidol, fentanyl, nitrous oxide, and oxygen, each child received one of the following muscle relaxants: succinylcholine 1.5 mg X kg-1 (n = 12), succinylcholine 1.0 mg X kg-1 (n = 13), pancuronium 0.15 mg X kg-1 (n = 11), or pancuronium 0.10 mg X kg-1 (n = 13). The force of thumb adduction was measured by stimulating the ulnar nerve with repetitive supramaximal single twitches (0.15 Hz). ⋯ The intubating conditions were excellent in 100% of the children who received succinylcholine 1.5 and 1.0 mg X kg-1, and pancuronium 0.15 mg X kg-1, but were excellent in only 69 per cent of those who received pancuronium 0.10 mg X kg-1. We conclude that succinylcholine 1.5 mg X kg-1 produces the most rapid onset of excellent intubating conditions in children. In children in whom succinylcholine is contra-indicated, pancuronium 0.15 mg X kg-1 provides excellent intubating conditions within 80 seconds.
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The hypothesis that administration of neostigmine in divided doses might accelerate the antagonism of neuromuscular blockade was investigated. Neostigmine 0.05 mg X kg-1 was administered either in a single bolus dose (Group I, n = 16) or in an initial dose of 0.01 mg X kg-1 followed three minutes later by 0.04 mg X kg-1 (Group II, n = 16) for antagonism of atracurium-induced blockade. ⋯ The rate of TOF ratio recovery was 2.5 times faster after neostigmine administration in divided doses. It is concluded that administration of neostigmine in divided doses, as described in this study, produced a significantly faster reversal of residual atracurium-induced neuromuscular blockade as compared to a single bolus administration.
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Transcutaneous oxygen tension (PtcO2) was measured in 30 patients scheduled for elective pulmonary resection requiring one-lung ventilation during anaesthesia. Simultaneous PtcO2 and arterial oxygen tension (PaO2) measurements were taken preoperatively (preop), intraoperatively during two-lung endotracheal (ET) and one-lung endobronchial ventilation (EB), and postoperatively (postop). There was a significant correlation (r) between PtcO2 and PaO2 at all time periods: 0.97 (preop); 0.91 (ET); 0.83 (EB); 0.81 (postop). ⋯ In three, this was associated with arterial hypoxaemia and in one, haemodynamic compromise. In all four cases the PtcO2 was the first monitored parameter to change. As there is a substantial risk of developing hypoxaemia during thoracic anaesthesia, PtcO2 monitoring provides valuable early warning of impending hypoxaemia or haemodynamic compromise, thereby facilitating early therapeutic intervention.
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We studied the relationship between arterial carbon dioxide tension (PaCO2) and fresh gas flow (FGF) during use of the Bain breathing circuit for Caesarean section anaesthesia. Thirty-one patients undergoing Caesarean section were anaesthetised using the Bain circuit with intermittent positive pressure ventilation. ⋯ This is probably because the total FGF determined by body weight and given during Caesarean section anaesthesia is 15-20 per cent higher than nonpregnant levels, due to the weight gain associated with pregnancy. A FGF of 100 ml X kg-1 of pregnant weight/min maintains PaCO2 of 4.44 kPa predelivery, which is in the desirable range of PaCO2 during Caesarean section.
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The commonly used vasodilators sodium nitroprusside and nitroglycerin increase intracranial pressure (ICP) and cause tachycardia. Since diltiazem is also a vasodilator, we designed this experiment in cats to study its effect on intracranial pressure and heart rate (HR). Twelve cats were assigned to two equal groups. ⋯ Both groups received an infusion of diltiazem to decrease the mean blood pressure (BP), which was maintained 30 per cent below the baseline value for 15 minutes. Diltiazem caused no significant change in ICP (5.7 +/- 1 to 6.7 +/- 1.5 mmHg, p less than 0.01) in cats with N-ICP while in cats with AR-ICP, the increase from 26.9 +/- 0.5 to 34.0 +/- 1.9 mmHg was significant (p less than 0.006). HR decreased significantly during the diltiazem infusion in both groups.