Errors and clinical supervision of intubation attempts by the inexperienced

Background: Tracheal intubation is an essential skill for anaesthetists and other disciplines that require emergency establishment of a secure airway. Early attempts in patients often meet with failure. Existing publications focus mainly on trainees in emergency settings and highlight the role of experience in success; most recommend prior simulation training. Common factors identified as contributing to difficulty have been difficult airways, emergencies and rapid sequence induction. Early intubation skill development in patients with anticipated straightforward airways in a controlled environment has received little attention. Objectives: This qualitative observational study aimed to identify common difficulties associated with a supervised intubation process by inexperienced personnel in the relatively stress-free conditions of elective surgical procedures in the operating theatre. Methods: Following institutional and ethical approval, participants, supervisors, anaesthetic assistants and patients consented to observation and video-recording of supervised intubations in a Durban teaching hospital. Anonymity and confidentiality were assured. Contemporaneous observations were recorded in theatre, and video-recordings were subsequently reviewed for content. Errors, and interactions between supervisor, assistant and participant, and associated outcomes, were identified. Results: Twenty participants (medical interns and medical, paramedical and nursing students) performing 72 intubations were observed. All participants had prior training using manikins or simulators. There were 61 successful intubations and 11 unsuccessful attempts. Factors associated with failure included unfamiliarity with airway, equipment or process. Process errors included inadequate head positioning, laryngoscope handling and tracheal tube manipulation. Anaesthetic assistants contributed to difficulties in some cases. Supervisor support was either verbal, physical or both. Less experienced supervisors tended to intervene earlier. There was a significant trend for success associated with the reported number of prior successful intubations. A successful intubation within the study was, however, no guarantee of subsequent success. Conclusion: Despite prior simulation training, many participants demonstrated lack of familiarity with the airway, intubation process and equipment. While improved simulation training might partly address these issues, supervision of early clinical intubation attempts needs to be redirected from the process of intubation itself to the process of intubation skills acquisition. A first step would be to ensure that all supervisors and assistants are trained for the latter goal, anticipating common errors and providing standardised conditions for success. The use of video-recording of the events is an invaluable aid to observation and interpretation, and is recommended as an adjunct to further studies of mechanical skills transfer

The research component of specialist registration--a question of alligators and swamps? A personal view.

The recent implementation of the research requirement for specialist registration presents difficulties with regard to the provision of research supervision, particularly in those medical schools that previously followed the path of qualification via the Colleges of Medicine of South Africa examinations. The differences between the requirements for research supervision as stated in the Health Professions Council of South Africa memorandum and those of the Committee for Higher Education are causing disparities between medical schools similar to those that led to the memorandum in the first place. While the research component of specialist training can only improve the quality of both patient care and academic endeavour, it requires an enormous investment of time on the part of both the specialist trainees and their supervisors. In order to deal with this, specific issues outlined in the article need to be addressed.

Prevention and treatment of cardiovascular instability during spinal anaesthesia for caesarean section.

Spinal anaesthesia is the method of choice for caesarean section. There is however a significant associated morbidity and mortality in South Africa, particularly in inexperienced hands. This review provides recommendations for safe practice for anaesthetists at all levels of expertise, with particular reference to the management of haemodynamic instability.

Anaesthesia for electroconvulsive therapy: a comparison of sevoflurane with propofol.

This study was a prospective audit of patients receiving either intravenous induction of anaesthesia with propofol 2 mg/kg or inhalational induction using 8% sevoflurane for patients undergoing electroconvulsive therapy (ECT). All patients received inhaled 50% nitrous oxide. The anaesthetic agent was determined by psychiatrist preference. Each psychiatrist nominated only one induction technique for all his or her patients. Seventy treatments were studied in each group. Induction time was longer in the sevoflurane group. The time from commencing induction to loss of verbal contact was [mean (SD)] 64 (29.9) seconds for sevoflurane and 36 (33.6) seconds for propofol (P=0.001). Time to loss of eyelash reflex was 82 (32.6)s for sevoflurane and 44 (17.9)s for propofol (P<0.001). The duration of seizure activity was longer in sevoflurane patients, 35 (17.8)s, compared with 20 (9.8)s in the propofol group (P< 0.001). Discharge times were similar Minor adverse effects occurred in three patients, all in the sevoflurane group (one bradycardia and two episodes of post-procedural nausea). There were no major adverse events in either group. Propofol and sevoflurane both appear to be suitable agents for induction of anaesthesia for ECT.

Anaesthesia and analgesia for the critically ill parturient.

Anaesthetic and analgesic techniques in the critically ill are determined largely by the nature of the presenting illness. The commonest conditions likely to present as life-threatening emergencies are pre-eclampsia, obstetric haemorrhage, cardiac disease and severe sepsis. Issues dictating choice of anaesthetic technique are the patient's ability to maintain her airway, coagulation status, intravascular volume and haemodynamic dependence upon sympathetic drive, and requirements for ventilatory support and intensive care. Fetal well-being is an issue in the antepartum period, uteroplacental blood flow should be maintained and hypotension avoided. Maternal survival takes priority, however, and occasionally general anaesthetic techniques must be used which lead to neonatal respiratory depression and requirement for ventilatory support. Anaesthesia itself is associated with known hazards. The risks of each technique must be balanced against possible benefits in the context of the presenting illness.

Mivacurium for caesarean section in hypertensive parturients receiving magnesium sulphate therapy.

The interaction between mivacurium and magnesium sulphate was investigated in a group of parturients undergoing caesarean section under general anaesthesia. Thirty parturients were studied; 10 normotensive controls (group NT), 10 hypertensive controls (group HT) and 10 hypertensives who received magnesium sulphate (group HTM). At induction group HT received 30 microg/kg of alfentanil and group HTM 10 microg/kg of alfentanil and 30 or 60 mg/kg of magnesium sulphate. Neuromuscular function was monitored by electromyography. Mivacurium 0.15 mg/kg was given after 60% recovery of T1 following succinylcholine. Magnesium concentrations and plasma cholinesterase activity were significantly elevated in group HTM (1.57 +/- 0.53 mmol/1 and 4.60 +/- 1.27 kU/1) compared with group HT (0.71 +/- 0.18 mmol/1 and 3.44 +/- 0.97 kU/1) and group NT (0.60 +/- 0.07 mmol/1 and 2.86 +/- 0.82 kU/1) (P < 0.005). Time to maximal recovery, and time from 25-75% of maximal recovery from mivacurium, were significantly prolonged in group HTM (60.9 +/- 15.3 min and 16.8 +/- 5.6 min) compared with group HT (34.9 +/- 7.6 min and 7.6 +/- 3.6 min) and group NT (37.4 +/- 14.4 min and 8.5 +/- 3.4 min) (P < 0.01). Time to 25% recovery was prolonged in group HTM (35.1 +/- 7.4 min) compared with the other two groups (HT: 21.6 +/- 6.4 min and NT: 22.8 +/- 10.2 min) (P < 0.01). Whilst the duration of action of mivacurium, determined by electromyography, is prolonged by subtherapeutic serum magnesium concentrations, of the available non-depolarizing relaxants mivacurium would seem to be most appropriate for caesarean section.

A laboratory assessment of oxygen delivery from a portable chemical generator.

A simple portable chemical oxygen generator was tested in the laboratory. The device is designed for use by the public as an oxygen supply until an emergency team arrives with appropriate oxygen cylinders. The generator was found to supply a mean (SD) flow of oxygen of 3.6 (0.01) l.min-1 for 12.5 (range 12.4-12.6)min. The mean (SD) total volume of oxygen produced was 47(0.17) l. The supplied oxygen mask was a variable performance type with the problems and limitations inherent in this design; an oxygen flow of 8 l.min-1 is required to provide 40% oxygen and most of the oxygen is wasted and not available to the patient. This poses a serious limitation to any device which has a limited capability (in flow and/or total volume) for producing oxygen.

Use of a mechanical simulator for training in applying cricoid pressure.

Using an airway management training model, we have assessed anaesthesia personnel in their use of correct cricoid force and ability to retain this skill after a short training programme. A perspex device, working on a hydraulic principle, was used to measure cricoid pressure when applied to the model. After initial assessment at two levels of cricoid force (20 and 40 N), participants undertook additional training on 3 consecutive days. Thereafter, available participants underwent reassessment at 14-21 days. Forty-nine anaesthetic assistants and anaesthetists underwent initial assessment and 18 completed the full training and reassessment. Untrained, the majority (63%) of participants applied inadequate cricoid force with a wide variation (mean 16.8 (SD 9.3) (range 4.5-43.0) at 20 N and 32.9 (13.3) (14.9-74) at 40 N). After a single training session there was a marked improvement in application of cricoid force. Two additional training sessions did not provide further improvement. After 14-21 days the ability of participants to apply correct cricoid force was retained by 72% of subjects. Those who applied inadequate cricoid force initially were more likely to do so even after training. Most subjects applied too great a cricoid force in the first 5 s of application followed by a progressive loss of force during the next 20 s. This trend improved after training. We conclude that the majority of untrained personnel apply inadequate cricoid force, placing patients at risk of aspiration of gastric contents. While a simple training programme improved application of cricoid force, retained for up to 3 weeks, there was often a substantial decrease in the force applied to the cricoid during a single application, even after training.

Intravenous administration of the proton pump inhibitor omeprazole reduces the risk of acid aspiration at emergency cesarean section.

This study documented gastric pH and volume, and the number of patients at risk for acid aspiration of gastric contents, in a group of mothers undergoing emergency cesarean section under general anesthesia. Patients were randomized in a double-blind fashion to receive omeprazole 40 mg intravenously or placebo at the time of decision to proceed to cesarean section. In addition, all patients received 10 mg intravenous metoclopramide and 30 mL of 0.3 M sodium citrate. Aspiration of gastric contents was undertaken immediately after endotracheal intubation (PI) and before tracheal extubation (PE). Patients with both pH < 3.5 and volume > 25 mL were deemed to be at risk of acid aspiration should regurgitation occur. Only cases where the study-drug-to-PI-aspiration interval was > 30 min were evaluated. There were 282 patients in the study group and 259 in the control group. PI, 11 patients (4.25%; 95% confidence interval [CI] 1.79-6.71) were at risk in the control group compared with 4 (1.42%; 95% CI 0.04-2.8) in the study group (P = 0.045). The omeprazole-to-PI-aspiration interval in these four cases was < or = 40 min. PE, 19 (7.3%; 95% CI 4.17-10.51) patients were at risk in the control group compared with 2 (0.7%; 95% CI 0-1.69) in the study group (P < 0.0001). Mean pH in patients receiving omeprazole was significantly higher (P < 0.001) than in the control group. Gastric volumes were significantly lower in the omeprazole group compared with the control group at both PI (P = 0.006) and PE (P = 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Laboratory assessment of a user-assembled oxygen generation kit.

A laboratory assessment was made of a user-assembled oxygen generation kit designed for use in medical emergencies in the community. Twenty-five kits were studied at five different water temperatures and the rate of oxygen generation and its concentration were measured. The apparatus produced a mean (SD) oxygen volume of 37 (1.98) l which was not affected by the starting water temperature. The mean (SD) rate of flow varied from 2.2 (0.04) l.min-1 at 16 degrees C to 10.3 (2.74) l.min-1 at 40 degrees C but the duration of flow varied inversely. Oxygenation concentrations ranging from 30-51% were produced at starting water temperatures from 22 degrees C-40 degrees C, respectively.

A reevaluation of the role of crystalloid preload in the prevention of hypotension associated with spinal anesthesia for elective cesarean section.

BACKGROUND: Hypotension after spinal anesthesia for cesarean section remains a common and serious complication despite the use of uterine displacement and volume preloading. The current study revaluated the role of crystalloid volume preloading in this context. METHODS: In a two-stage open sequential design, patients presenting for elective repeat cesarean section were allocated to receive either no preload or 20 ml/kg crystalloid administered over 15-20 min before spinal anesthesia. Hypotension was defined as a decrease in systolic pressure to less than 100 mmHg and to less than 80% of baseline value, and the study was designed to detect a 20% difference in the incidence of hypotension between the groups, with statistical significance at the 10% (alpha = 0.1) level, one-tailed. RESULTS: One hundred forty patients were studied. Hypotension occurred in 43 (55%, 95% CI 43.4-66.4) preloaded and 44 (71%, 95% CI 58-81.8) unpreloaded subjects, a difference in incidence of 16% (95% CI 0.04-31.6), which was statistically significant. There were no significant differences in the severity, timing, or duration of hypotension; the dose requirement for ephedrine; or the clinical and biochemical status of neonates between the groups. The only difference seen was a lower mean base excess (-3.4, SD 2.81 mM-1) in the neonates of hypotensive mothers compared to neonates of nonhypotensive mothers (-2.4, SD 1.99 mM-1). CONCLUSIONS: The study confirms that hypotension associated with spinal anesthesia for cesarean section cannot be eliminated by volume preloading in the supine wedged patient. The relatively small reduction in incidence of hypotension challenges our perception of the value of crystalloid preload. Though volume preload in the elective cesarean section is advocated, the requirement for a mandatory administration of a fixed volume before spinal anesthesia for urgent cases has been abandoned.

Leg elevation and wrapping in the prevention of hypotension following spinal anaesthesia for elective caesarean section.

Ninety-seven parturients undergoing elective Caesarean section were allocated randomly to have their legs elevated to approximately 30 degrees on pillows or elevated and wrapped with elasticated Esmarch bandages or neither (controls) following spinal anaesthesia. All patients received intravenous crystalloid (20 ml.kg-1 over 20 min) prior to spinal injection and were placed in the left lateral tilt position. Significant hypotension was treated with intravenous ephedrine in 5 mg bolus doses. Leg wrapping resulted in a significant reduction in the incidence of postspinal hypotension in comparison to the control group (18% compared to 53%, p = 0.004). This represents a five-fold reduction in the likelihood of postspinal hypotension (odds ratio 5.3, 95% CI 1.7-16.3). Leg elevation alone did not significantly reduce the incidence of hypotension (39%). There was no significant difference in the time of onset of hypotension between the groups. For those patients requiring ephedrine, there was no significant difference in mean dose requirements between the groups. The use of leg compression immediately postspinal provides a simple means of reducing the accompanying hypotension and should be used more widely.

Malignant ventricular arrhythmias in eclampsia: a comparison of labetalol with dihydralazine.

OBJECTIVE: Our aim was to assess the impact of beta-adrenergic blockade during the peripartum period on the previously observed high incidence of ventricular arrhythmias in eclamptic parturients. STUDY DESIGN: An open, randomized comparison of intravenous labetalol versus dihydralazine was conducted in 40 eclamptic subjects in the peripartum period. Cardiac rhythm was assessed by blinded analysis of a 24-hour Holter record by means of the Lown classification of arrhythmias. RESULTS: There was a significantly higher incidence of serious ventricular arrhythmias in patients receiving dihydralazine (81%) than in those receiving labetalol (17%, p < 0.0001). Patients receiving labetalol showed a significant decrease in mean heart rate (p < 0.0001), whereas patients receiving dihydralazine showed a significant increase (p < 0.0001). CONCLUSION: The introduction of beta-adrenergic blockade into peripartum hypertensive management of eclampsia significantly reduced the incidence of dangerous ventricular arrhythmias. Myocardial oxygen supply/demand ratio may be improved by beta-blockade.