Canadian Anaesthetists' Society journal最新文献

The effects of succinylcholine (1.5 mg X kg-1 IV) administered five minutes after a defasciculating dose of curare (0.05 mg X kg-1 IV), were compared with the effects of atracurium (0.5 mg X kg-1 IV) on intracranial pressure (ICP) in 13 cynomolgus monkeys with intracranial hypertension (ICP approximately 25 mmHg). Neither succinylcholine nor atracurium increased ICP during general anaesthesia with 60 per cent N2O/O2, 0.5-1 per cent halothane. During a rapid sequence induction and intubation with thiopentone 5 mg X kg-1 IV, ICP increased equally with intubation following both atracurium (25 +/- 1 to 32 +/- 2 mmHg) and succinylcholine (25 +/- 1 to 31 +/- 2 mmHg) (p less than 0.05). Intubation was also associated with significant increases in PaCO2, CVP and MAP. We conclude that in this primate model of intracranial hypertension, neither atracurium nor succinylcholine (when given following a defasciculating dose of curare) elevates ICP. In terms of the elevation of ICP associated with intubation, atracurium was found to offer no advantage over succinylcholine.

The effects of halothane and isoflurane anaesthesia on myocardial injury in rabbits subjected to coronary artery ligation and subsequent reperfusion were analyzed. Although halothane and isoflurane (at inspired concentrations of 1.0 and 1.5 per cent, respectively) exerted comparable effects on cardiovascular status during ischaemic and reperfusion phases, greater preservation of subcellular integrity (as assessed by mitochondrial and sarcoplasmic reticular ATPase activities and myocardial ionic alterations) and a lower incidence of ventricular fibrillation and severe hypotension occurred with halothane. Our results indicate that in studies of experimental myocardial ischaemia anaesthetics may, independently of cardiovascular actions, influence the nature and extent of resulting injury, possibly by virtue of their differing effects on subcellular membrane systems.

The case histories are presented including the anaesthetic and postoperative management, of two children, a two-year-old with undiagnosed Duchenne muscular dystrophy (DMD) and a three-year-old with known DMD. The child with undiagnosed DMD had no symptoms of DMD and had received halothane twice before, without succinylcholine, with no apparent difficulty. Following an uneventful induction of anaesthesia with halothane, nitrous oxide and O2, succinylcholine resulted in bilateral masseter muscle spasm and then, in rapid sequence, ventricular tachycardia and cardiac arrest. Resuscitation was difficult, prolonged and associated with hyperkalaemia (K+ = 12.57 mEq X L-1), severe metabolic and respiratory acidosis, high peripheral venous pressure and massive hepatosplenomegaly, but not hyperthermia. The patient was finally resuscitated but died two days later. Skeletal muscle biopsy results were consistent with malignant hyperthermia. The second patient was known to have DMD but did not receive prophylactic or intraoperative dantrolene nor have his anaesthetic machine flushed with oxygen for an extended period prior to induction of anaesthesia. This child was anaesthetized with fentanyl and N2O and, with the exception of a high intraoperative heart rate (155-160 beats X min-1), had an uncomplicated anaesthetic and operation (intraoperative axillary temperatures ranged between 36.8-37.9 degrees C). Postoperatively his temperature rapidly increased to 38.8 degrees C and then 40.3 degrees C and he became metabolically acidotic. Intravenous administration of dantrolene for 48 hours reduced the temperature and allowed normal recovery and discharge. A postoperative muscle biopsy was consistent with DMD.(ABSTRACT TRUNCATED AT 250 WORDS)

A case report is presented describing the clinical usefulness of transcutaneous oxygen (PtcO2) monitoring in an infant undergoing tracheoesophageal fistula repair. Its use allowed early and precise recognition of hypoxaemia during periods of surgical manipulation. During periods of hypoxaemia, there were no associated cardiovascular changes or changes in routine monitoring modalities. Clinical use of PtcO2 may detect early hypoxaemia and thus allow for correction before the appearance of changes in vital signs.

Patterns of blood transfusion practice over an eight-year-period (1977-1984) are described. Use of blood and blood products increased annually as did the number of patients crossmatched and transfused. Programs such as the "Blood Group & Antibody Screen" and the "Maximum Surgical Blood Order Schedule" were important in improving transfusion practices. There was improvement in blood use by all subspecialties; the overall C:T (crossmatched:transfused blood) ratio declined from 4.4 to 2.8. Approximately a quarter of both crossmatches performed and transfusions of red cells were associated with cardiac surgery. Incidence of outdated units of blood declined markedly (2.6 per cent in 1984), as did requests for and administration of single unit transfusions. Seven per cent of patients received one unit of blood during hospitalization; since 85 per cent of these were associated with surgery (57 per cent cardiac surgery), it is suggested that single unit transfusions may sometimes be more appropriate than inappropriate. Two per cent of patients had clinically significant alloantibodies. About two per cent of patients had positive direct antiglobulin tests; nine per cent of the sera of these patients contained both auto and alloantibodies. Such data are important for transfusion quality assurance as well as for optimal logistical use of facilities both at hospital Blood Bank and blood collection agency levels.

A four year-old boy born without limbs (amelia) presented for dental restorations under general anaesthesia as an outpatient. Following intramuscular atropine administration anaesthesia was induced using halothane, oxygen and nitrous oxide inhaled by mask. Next, intravenous access was secured by external jugular vein catheterization. Because of his small mouth, hypognathic mandible, arched palate and anterior-superiorly located larynx, oral intubation under deep anaesthesia during spontaneous ventilation was difficult. The epiglottis was noted to be inverted on subsequent laryngoscopic inspection after intubation but was reduced mechanically to anatomic position. Despite being unable to accurately monitor the blood pressure the intraoperative period was uneventful. Postoperatively the patient was extubated and was able to return home the same day.

An episode of malignant hyperthermia occurring in a two-year-old child undergoing cardiac surgery is reported. The coincidental usage of hypothermic cardiopulmonary bypass obscured the classical presenting signs and symptoms of the syndrome. Once the clinical diagnosis was confirmed, rapid reversal was achieved with the administration of dantrolene sodium.

This study compared the haemodynamic and arginine vasopressin responses of patients to fentanyl or sufentanil anaesthesia for coronary artery bypass surgery. Fourteen normotensive patients with normal left ventricular function were studied. Patients were induced with fentanyl (N = 7) 37.5 micrograms X kg-1 or sufentanil (N = 7) 7.5 micrograms X kg-1 by intravenous infusion over three minutes. Clinically important chest wall rigidity, bradycardia and recall of intraoperative events did not occur. All of the fentanyl patients became hypertensive after induction and five required vasodilator therapy since they did not respond to boluses of fentanyl (12.5 micrograms X kg-1). Two of these five patients had S-T depression greater than 1 mm. Five patients in the sufentanil group became hypertensive after induction. Four of these patients responded to additional sufentanil (3.75 micrograms X kg-1) while one required vasodilator therapy for concomitant S-T depression. Sufentanil attenuated the increase of arginine vasopressin during cardiopulmonary bypass. Levels of arginine vasopressin in the fentanyl group were significantly higher than those of the sufentanil group during bypass. Levels of AVP after bypass were higher in the sufentanil group. The incidence of hypertension was similar in both groups. The hypertension was more easily treated with sufentanil but concomitant vasodilators (nitroglycerine) were required in both patient groups. Neither fentanyl in doses up to 128 +/- 8.7 micrograms X kg-1 nor sufentanil in doses up to 23 +/- 1.4 micrograms X kg-1 can be used as sole agents for anaesthesia in adult coronary artery bypass patients with good ventricular function when induction times are three minutes and bolus top-up doses are used.

The effects of atracurium 0.5 mg X kg-1 or succinylcholine 1.0 mg X kg-1 on intraocular pressure (IOP) were studied in ten patients during steady state nitrous oxide-oxygen-fentanyl anaesthesia. IOP was unchanged following atracurium but, one minute after succinylcholine, it had increased significantly (p less than 0.025) from 5.6 mmHg to 13.2 mmHg and remained significantly above control for 3 min. Twenty additional patients received either atracurium 0.75 mg X kg-1 or succinylcholine 1.0 mg X kg-1 as part of a rapid sequence induction, atracurium being administered prior to, and succinylcholine after, thiopentone. Intubating conditions were acceptable in all patients in both groups. Administration of thiopentone was associated with a significant (p less than 0.025) decrease in IOP. Although IOP increased in both groups as a result of laryngoscopy and intubation (from 8.0 mmHg to 12.1 mmHg in the atracurium Group and from 7.5 mmHg to 14.5 mmHg in the succinylcholine group) it did not exceed pre-induction IOP in the former. In the succinylcholine group, IOP after intubation exceeded pre-induction values for 2 min, although this increase was significant (p less than 0.05) only at the immediate post-intubation reading. It is concluded that atracurium in a dose of 0.75 mg X kg-1 is a suitable relaxant for use in rapid sequence induction.

To determine the optimal priming dose for administration in divided doses, atracurium was given to 77 patients either in a single dose of 0.5 mg X kg-1 or in an initial dose of 0.04, 0.05, 0.06, 0.07, 0.08 or 0.09 mg X kg-1, followed three minutes later by the remainder of the 0.5 mg X kg-1 dose. Patients were anaesthetized throughout the study. When atracurium was given as a single bolus of 0.5 mg X kg-1, the mean time to complete neuromuscular block was 141.5 seconds. Administration in divided doses accelerated the onset time (p less than 0.01), that is the time from the intubating dose to the complete suppression of train-of-four (TOF) response. The TOF ratio decreased slightly but statistically significantly following the priming doses. When the priming dose was 0.05 mg X kg-1, the mean onset time was 70.9 seconds and priming with larger doses did not add any further advantage. It is concluded that 0.05 mg X kg-1 appears to be the optimal priming dose for the administration of atracurium in divided doses. When 0.05 mg X kg-1 is given three minutes before the intubating dose, tracheal intubation can be accomplished in less than 90 seconds.