The effect of low molecular weight heparin (enoxaparin) on enhanced coagulation induced by crystalloid haemodilution.

The purpose of this study was to establish whether a low molecular weight heparin (enoxaparin) attenuated or abolished the enhanced coagulation induced by crystalloid fluid therapy. Twenty young, healthy male volunteers were injected subcutaneously with either enoxaparin 40 mg or saline on two separate occasions one week apart, in a randomised, blinded study. Twelve hours later, a blood sample was taken for thrombelastography analysis and haematocrit. Saline 14 ml.kg⁻¹ was then infused over thirty minutes and thrombelastography and haematocrit measurements repeated. There was a significant post-dilutional difference in the alpha angle (p = 0.002) and k-time (p = 0.001) between the two groups. There was a trend towards reduced shortening of r-time in the enoxaparin group compared to the saline control (p = 0.18). The findings suggest that enoxaparin diminished acceleration of clot formation due to haemodilution.

Drug administration errors: a prospective survey from three South African teaching hospitals.

This prospective study was undertaken to determine the incidence of drug administration errors by anaesthetists at three tertiary South African hospitals. Hospitals A and C treat adults predominantly, whereas Hospital B is a paediatric hospital. Anaesthetists completed an anonymous study form for every anaesthetic performed over a six-month period. They were asked to indicate whether or not an error or near-miss had occurred and if so, the details thereof. A total of 30,412 anaesthetics were administered during the study period. The response rate and combined incidence of errors and near-misses was as follows: Hospital A 48.8% (1:320), B 81.3% (1:252) and C 48.1% (1:250). The overall response rate was 53% and the combined incidence was 1:274. Neither the experience of the anaesthetist nor emergency surgery influenced whether an error occurred or not. Most errors occurred during the maintenance phase of anaesthesia. The most common errors were those of substitution. At the paediatric hospital, incorrect dose was as frequent an error as substitution. Of all errors, 36.9% were due to drug ampoule misidentification; of these the majority (64.4%) were due to similar looking ampoules. Another 21.3% were due to syringe identification errors. No major complication attributable to a drug administration error was reported. Despite an increasing awareness of the problem together with suggestions in the literature to reduce the incidence, drug administration errors remain fairly common in South Africa. Failure to institute suggested solutions will continue to compromise patient safety.

Drug administration errors by South African anaesthetists--a survey.

OBJECTIVES: To investigate the incidence, nature of and factors contributing towards wrong drug administrations by South African anaesthetists. DESIGN: A confidential, self-reporting survey was sent out to the 720 anaesthetists on the database of the South African Society of Anaesthesiologists. RESULTS: A total of 133 questionnaires were returned for analysis (18.5% response rate). Of the respondents, 125 (94%) admitted to having inadvertently administered a wrong drug. Thirty respondents (22.6%) said they had made errors on at least four occasions. A total of 303 specific wrong drug administrations were described. Nearly 50% involved muscle relaxants. A further 43 incidents (14%) involved the erroneous administration of vasoactive drugs. Five deaths and 3 nonfatal cardiac arrests were reported. In 9.9% of incidents the anaesthetic time was prolonged by more than 30 minutes. Contributory causes identified included syringe swaps (40%), misidentification of drugs (27.1%), fatigue (14.1%), distractions (4.7%), and mislabelling of syringes (4.7%). Only 19% of respondents regularly use colour-coded syringe labels complying with the national standard. CONCLUSIONS: Most anaesthetists experienced at least one drug error. The incidence of wrong drug administrations by South African anaesthetists appears to be similar to that in Australasia and Canada. The commonest error was a 'syringe swap' involving muscle relaxants. Most drug errors are inconsequential. An important minority of incidents result in severe morbidity or death. The study supports efforts to improve ampoule labelling, to encourage the use of syringe labels based on the international colour code and to develop a national reporting system for such incidents.

The effect of eltanolone on pulmonary vascular resistance in landrace swine.

This paper reports on the haemodynamic effects of eltanolone observed in Landrace swine during the investigation of the drug with respect to safety in malignant hyperthermia-susceptible individuals. Pigs were sedated with intramuscular ketamine, followed by induction of anaesthesia employing thiopentone administered via an ear-vein. After intubation, anaesthesia was maintained using nitrous oxide in oxygen. A total of eight pigs were then further anaesthetised on two separate occasions using one of two dose schedules. A bolus of 1.5 mg kg(-1) of eltanolone was administered, followed by a continuous infusion at either 2 or 10 mg kg(-1) h(-1). There were no significant changes in heart rate, mean arterial pressure, cardiac output or systemic vascular resistance following eltanolone. In all cases eltanolone induced marked rises in pulmonary artery pressure and pulmonary vascular resistance (P<0.01) at all measuring points and in right ventricular stroke work at 6-10 min after drug exposure. We conclude that the selective influence of eltanolone on the pulmonary vasculature is probably species-specific, but may have clinical significance in patients with pulmonary hypertension.

Eltanolone (5-beta-pregnanolone) does not trigger, and attenuates halothane triggering of, malignant hyperthermia in malignant hyperthermia susceptible swine.

Eltanolone is the lipid emulsion formulation, for intravenous use, of the steroid anaesthetic 5-beta-pregnanolone. We have screened this agent in malignant hyperthermia susceptible (MHS) Landrace swine to assess its potential to trigger the Malignant Hyperthermia (MH) syndrome in MHS subjects or to influence halothane triggering of MH in such patients. Administered in anaesthetic concentration, eltanolone did not trigger the MH syndrome in MHS swine. When co-administered in low dosage with halothane, the drug prevented initiation of the MH syndrome in four of eight pigs and attenuated its progress in the remainder.

Total i.v. anaesthesia with propofol and the laryngeal mask for orthopaedic surgery.

One hundred ASA I orthopaedic surgical patients (four randomized groups) were anaesthetized using continuous propofol and intermittent fentanyl (TIVA), with controlled ventilation via a tracheal tube in groups 1 and 2, and a laryngeal mask airway (LMA) in groups 3 and 4. Neuromuscular blockers were used in groups 1 and 3 only. There were no significant differences between groups in total anaesthetic requirements, as assessed by cardiovascular variables and movement. Coughing interfered with surgery and made controlled ventilation difficult to manage. In contrast, movement not associated with coughing did not impair surgery or ventilation. Patients in group 2 (tracheal tube, no neuromuscular blocker) required more interventions for coughing than the other groups, while patients in group 4 (LMA, no neuromuscular blocker) needed more boluses for movement than groups 1 and 3. Groups 1 and 2 (tracheal tube) had significantly higher heart rates and mean arterial pressures than groups 3 and 4 for varying periods up to 5 min after insertion of the airway management device. There was no correlation between mean arterial pressure and plasma concentrations of catecholamines related to insertion of either the tracheal tube or LMA. The LMA was found to be a highly effective device for controlled ventilation in TIVA and easier to manage than the tracheal tube in the absence of neuromuscular blockers.