Non-heart-beating organ donation.
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Brain Death↗
Biomedical subjects
J H Devitt
Publications and source records attributed to J H Devitt.
Inadequate preanesthesia equipment checks in a simulator.
PURPOSE: To assess how completely anesthesiologists check their machinery and equipment before use, and to determine what influence seniority, age and type of practice may have on checking practices. METHODS: One hundred and twenty anesthesiologists were videotaped during a simulated anesthesia session. Each participant was scored by an assessor according to the number of items checked prior to the induction of anesthesia. A checklist of 20 items derived from well-publicized, international standards was used. RESULTS: Participants were grouped according to their type of practice. Overall, mean scores were low. The ideal score was 20. There were no differences among university anesthesiologists (mean score 10.1, standard deviation 4.3), community anesthesiologists (7.5 +/- 4.3) and anesthesia residents (9.0 +/- 3.8). Each of these groups scored, on average, better than medical students (3.6 +/- 3.7) (P < 0.05). Neither age (r = 0.15, P > 0.1) nor number of years in practice (r = -0.18, P > 0.1) correlated with score. CONCLUSIONS: Our study suggests that the equipment-checking practices of anesthesiologists require considerable improvement when compared with national and international standards. Possible reasons for this are discussed and some remedial suggestions are made.
Anesthesiology↗
The anesthetic record: accuracy and completeness.
PURPOSE: To evaluate if anesthesia training and experience influenced chart completion and accuracy. METHODS: One hundred and twenty-four subjects, including medical students, anesthesia residents and community and university based clinical anesthesiologists, were given a standardized patient in a simulator environment and asked to conduct induction and maintenance of anaesthesia. Three critical events were introduced resulting in changes in BP, HR, PETCO2 and SpO2. Subjects were instructed to manage the patient and the anesthetic chart, as was their customary practice. Discrepancy, calculated as the difference between the actual and charted values divided by the actual physiological value was compared by level of training with a two-way repeated measures analysis of variance (ANOVA) for all four physiological variables. The completeness of charting, defined as at least one data point recorded for each of the four physiological variables of the three critical events, was compared across level of training, age of participants and number of years in practice. RESULTS: The overall completeness of charting remained low (< 37%) with no relationship based on the anesthesiologist's age, level of training or number of years in practice. There was discrepancy in charting for all physiological variables (HR, BP, PETCO2 and SpO2, P < 0.0001), with a marked difference in the degree of discrepancy within each level of training. Training resulted in no differences in charting discrepancy. CONCLUSION: Charting of data to the anesthetic record remained incomplete and inaccurate in all groups based on level of training, age and number of years in practice.
Adult↗
Gas leak and gastric insufflation during controlled ventilation: face mask versus laryngeal mask airway.
PURPOSE: To compare two airway management techniques, face mask (FM) with oropharyngeal airway and laryngeal mask airway (LMA), with respect to the effectiveness of positive pressure ventilation and airway maintenance. METHODS: After induction of anaesthesia, two airway management techniques (FM or LMA) and three peak pressures (20, 25 and 30 cm H2O) were randomly applied during controlled ventilation in 60 patients. Data collected included inspiratory and expiratory volumes and presence of gastro-oesophageal insufflation. Leak was calculated by subtracting the expiratory from the inspiratory volume, expressed as a fraction of the inspiratory volume. RESULTS: Expiratory volumes (mean +/- SD) at 20, 25 and 30 cm H2O for LMA ventilation were 893 +/- 260, 986 +/- 276 and 1006 +/- 262 respectively, and for FM ventilation 964 +/- 264, 1100 +/- 268 and 1116 +/- 261. Leak fractions at 20, 25 and 30 cm H2O for LMA ventilation were 0.21 +/- 0.15, 0.24 +/- 0.18 and 0.26 +/- 0.18 respectively, and for FM ventilation 0.14 +/- 0.09, 0.14 +/- 0.09 and 0.12 +/- 0.08. The frequency of gastro-oesophageal insufflation was 1.6%, 5% and 5% for the LMA and 5%, 15% and 26.6% for the FM for ventilation pressures of 20, 25 and 30 cm H2O respectively which was greater with LMA use. CONCLUSION: Ventilation was adequate in all patients using both techniques. Leak was pressure dependent and greater with LMA use. Most of the leak was vented to the atmosphere via the pharynx. Gastro-oesophageal insufflation was more frequent with ventilation using the face mask. LMA use with positive pressure ventilation would appear to be a better airway management method than the face mask.
Adult↗
Cardiac arrest in the OR: how are our ACLS skills?
PURPOSE: While advanced cardiac life support (ACLS) training is widely available, it is not mandatory for all anaesthetists. We hypothesised that adherence to ACLS guidelines during resuscitation of ventricular fibrillation (VFib) as assessed in a simulator environment would be poor by anaesthetists not trained in ACLS compared with those who had received training. METHODS: With approval by the ethics review board, 89 subjects participated in the study. The simulation system consisted of a computer controlled mannequin with lifelike qualities set in a mock operating room. Each subject was given a test scenario that contained several standard anaesthetic problems. A VFib cardiac arrest occurred after approximately one hour into the simulation. A perfect score (score = A) defined complete compliance with the ACLS guidelines, whereas minor deviations (score = B) included changes in energy levels, drug doses or treatment order. The failure to discontinue the anaesthetic, defibrillate or administer epinephrine were considered major deviations (score = C). RESULTS: Eight subjects followed the ACLS guidelines (9%, score = A), while 27 subjects showed minor (30%, score = B) and 54 subjects major deviations (61%, score = C). Sixty-two of the 89 participants (70%) had taken the ACLS course and achieved higher scores than did anaesthetists without such training (P < 0.05). Forty-two participants (47%) did not discontinue the anaesthetic, 10 (11%) never gave epinephrine and 5 (6%) never used the defibrillator. CONCLUSION: Adherence to ACLS guidelines was poor. A greater proportion of subjects without previous ACLS training had deviations from protocol than did subjects who had received training. We need to consider ways to ensure that anaesthetists obtain and retain resuscitation skills according to ACLS guidelines.
Adult↗
Testing internal consistency and construct validity during evaluation of performance in a patient simulator.
UNLABELLED: The primary goal of this study was to test the items in a rating system developed to evaluate anesthesiologists' performance in a simulated patient environment. A secondary goal was to determine whether the test scores could discriminate between resident and staff anesthesiologists. Two 5-item clinical scenarios included patient evaluation and induction and maintenance of anesthesia. Rating scales were no response to the problem (score = 0), compensating intervention (score = 1), and corrective treatment (score = 2). Internal consistency was estimated using Cronbach's coefficient alpha. Scores between groups were compared using the Cochran-Mantel-Haenszel test. Subjects consisted of 8 anesthesiology residents and 17 university clinical faculty. The Cronbach's coefficient alpha was 0.27 for Scenario A and 0.28 for Scenario B. Two items in each scenario markedly decreased internal consistency. When these four items were eliminated, Cronbach's coefficient alpha for the remaining six items was 0.66. Faculty anesthesiologists scored higher than residents on all six items (P < 0.001). A patient simulator-based evaluation process with acceptable reliability was developed. IMPLICATIONS: The reliability of anesthesia clinical performance in a patient simulation environment was assessed in this study. Of 10 items, 4 were poor in the evaluation process. When these items were removed, the reliability of the instrument improved to a level consistent with other studies. Because faculty scored higher than resident anesthesiologists, the instrument also showed discriminant validity.
Adult↗
Testing the raters: inter-rater reliability of standardized anaesthesia simulator performance.
PURPOSE: Assessment of physician performance has been a subjective process. An anaesthesia simulator could be used for a more structured and standardized evaluation but its reliability for this purpose is not known. We sought to determine if observers witnessing the same event in an anaesthesia simulator would agree on their rating of anaesthetist performance. METHODS: The study had the approval of the research ethics board. Two one-hour clinical scenarios were developed, each containing five anaesthetic problems. For each problem, a rating scale defined the appropriate score (no response to the situation: score = 0; compensating intervention defined as physiological correction: score = 1; corrective treatment: defined as definitive therapy score = 2). Video tape recordings, for assessment of inter-rater reliability, were generated through role-playing with recording of the two scenarios three times each resulting in a total of 30 events to be evaluated. Two clinical anaesthetists, uninvolved in the development of the study and the clinical scenarios, reviewed and scored each of the 30 problems independently. The scores produced by the two observers were compared using the kappa statistic of agreement. RESULTS: The raters were in complete agreement on 29 of the 30 items. There was excellent inter-rater reliability (= 0.96, P < 0.001). CONCLUSIONS: The use of videotapes allowed the scenarios to be scored by reproducing the same event for each observer. There was excellent inter-rater agreement within the confines of the study. Rating of video recordings of anaesthetist performance in a simulation setting can be used for scoring of performance. The validity of the scenarios and the scoring system for assessing clinician performance have yet to be determined.
Anesthesia, General↗
The cost for construction and operation of a simulation centre.
PURPOSE: Lack of financial information results in planning difficulties and may delay the introduction of simulator based education. We collected data from an existing simulation centre and describe a construction and operating budget to facilitate planning and construction for interested institutions. METHODS: After obtaining approval from the managing board, the plans and financial statements of the Canadian Simulation Centre, Sunnybrook Health Science Centre, University of Toronto were reviewed from the period from July 1994 through June 1996. Costs were calculated from the financial reports and separated into construction and operation phases. A list of the ongoing educational and research activities was compiled. RESULTS: All dollar figures are expressed in 1996 Canadian Dollars. The planning and construction took place from July 1994 through June 1995. Construction costs for the simulation centre totalled $665,000, of which 85% was related to capital equipment purchases and 15% for salary support. The net costs of ongoing education and research activities (3.35 days/week) were $167,250 from July 1995 through June 1996. About 65% of this consisted of salary support and was absorbed by the existing educational resources of the University of Toronto Department of Anaesthesia. CONCLUSION: Substantial resources are required for the construction of a simulation centre ($665,000) primarily use of capital equipment purchases. However, there is also a considerable operating cost per year ($167,250) which consists mostly of salary support.
Anesthesiology↗
Simulated anaesthetic emergencies.
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Anesthesiology↗
Lower airway injuries and anaesthesia.
PURPOSE: The perioperative management of lower airway injuries is a difficult clinical problem. Since few reviews present the management of this injury from an anaesthetic perspective, we undertook a literature review of this topic. SOURCES: A computerized search of the National Library of Medicine database using tracheal or bronchial injury as key words produced 140 English language citations. An eight-year chart review outlining our experience in an urban Canadian setting is also presented. FINDINGS: The most frequent findings in patients with injury to the lower airway are dyspnoea and surgical emphysema. Other findings include cough, haemoptysis, sucking neck or chest wounds, mediastinal emphysema or pneumothorax. Endoscopy with a fiberoptic scope is the technique of choice for diagnosis, airway management and as a preparatory step in planning of the surgical repair. An airway technique employing direct vision is preferable to blind attempts during tracheal intubation. The use of a double lumen endobronchial tube or selective endobronchial intubation may be needed to achieve adequate pulmonary ventilation. A number of prospective randomized clinical trials comparing conventional mechanical ventilation with high frequency jet ventilation in patients with acute lung injury have demonstrated no difference in effectiveness of ventilation or oxygenation. CONCLUSIONS: Patients with lower airway injuries usually present when they are least expected and are a challenge to manage. The clinical presentation of a lower airway injury may be overt or subtle. Resuscitation and anaesthetic management are directed towards control of the airway, maintenance of adequate pulmonary ventilation and management of blood loss.
Anesthesia↗
Anaesthesia simulators.
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Anesthesiology↗
Mask lung ventilation by ambulance personnel: a performance assessment.
We evaluated the ability of basic life support ambulance officers and anaesthetists to perform lung ventilation with a face mask. After induction of anaesthesia and institution of standardized airway conditions the ambulance officer or anaesthetist placed a mask on the patient's face and lung ventilation was commenced. The order of hand grip (one vs two hands) was randomized. The mask was connected to a ventilator which had flow and pressure transducers in the inspiratory and expiratory breathing circuits. The output of these devices was sent to an electronic integrator to determine volumes. Calibration of the flow transducers was made against a spirometer while ventilating a test lung. Oesophageal insufflation was determined by listening over the epigastrium with a stethoscope. Data collected included presence of gastro-oesophageal insufflation, inspiratory and expiratory volumes. Expiratory volumes for ambulance officers and anaesthetists at 30 cm H2O were greater than that of ambulance officers at 20 cm H2O (P < 0.001) but profession of the mask holder or hand grip had no effect on expiratory volume. There was no difference in the mask leak when the professions were compared but ambulance officers had a lower mask leak with a two-handed grip at 20 cm H2O (P < 0.001). Anaesthetists had a greater incidence of gastro-oesophageal insufflation when a two-handed mask grip was utilized (P < 0.05). In healthy relaxed patients there appeared to be little difference between the ambulance officers and qualified anaesthetists in airway maintenance or mask-holding ability.
Adolescent↗
Unsuspected tracheal rupture in blunt thoracic trauma.
The purpose of this report is to describe the discovery and management of an unanticipated injury during fibreoptic tracheal intubation. A 23-yr-old man sustained blunt cervical, thoracic and abdominal trauma in a motor vehicle accident. He was brought to the operating room for urgent management of his abdominal and cervical spine injuries. Examination of his airway during awake fibreoptic tracheal intubation revealed an unexpected tracheal injury. Surgical repair of the trachea was uneventful. The diagnosis and airway management of tracheal rupture are discussed. This case illustrates the importance of a full diagnostic examination during invasive anaesthetic procedures such as tracheal intubation.
Abdominal Injuries↗
The laryngeal mask airway and positive-pressure ventilation.
BACKGROUND: The utility of the laryngeal mask airway during positive-pressure ventilation has yet to be determined. Our study was designed to assess whether significant leaks occurred with positive-pressure ventilation and if leaks were associated with gastroesophageal insufflation. METHODS: Forty-eight patients undergoing elective surgery were studied. After induction of anesthesia and paralysis, controlled ventilation was used with four different peak pressure settings in each patient (15, 20, 25, and 30 cmH2O). The order of ventilator pressure settings was assigned from a randomized block schedule. Data collected included inspiratory and expiratory volumes, qualitative assessments of gastroesophageal insufflation, and leak at the neck. After data collection during laryngeal mask use, the anesthesiologist intubated the trachea and measurements were repeated for tracheal tube ventilation. Leak was calculated by subtracting the expiratory from the inspiratory volume and expressed as a fraction of the inspiratory volume. RESULTS: Ventilation with the laryngeal mask airway was adequate at all ventilation pressures and comparable with tracheal tube ventilation. Leak fraction (mean +/- SD) at 15, 20, 25, and 30 cmH2O for laryngeal mask ventilation were 0.13 +/- 0.15, 0.21 +/- 0.18, 0.25 +/- 0.16 and 0.27 +/- 0.17, respectively, and 0.03 +/- 0.03, 0.05 +/- 0.03, 0.05 +/- 0.03 and 0.04 +/- 0.03, respectively, for tracheal tube ventilation. Leak fractions for ventilation with the laryngeal mask were consistently greater than those measured for tracheal tube ventilation at similar ventilation pressures. Leak fraction with laryngeal mask ventilation increased with increasing airway pressures, whereas leak with tracheal tube ventilation remained unchanged. The frequency of gastroesophageal insufflation ranged from 2.1% at a ventilation pressure of 15 cmH2O to 35.4% at 30 cmH2O. CONCLUSIONS: Ventilation using the laryngeal mask appears to be adequate if airway resistance and pulmonary compliance are normal. Gastroesophageal insufflation of air will become a problem in the presence increased ventilation pressure.
Adolescent↗
Blunt cardiac injury and intraoperative hypoxaemia.
A 28-yr-old man sustained blunt chest trauma in a motor vehicle accident. Severe intraoperative hypoxaemia occurred, unresponsive to oxygen and positive expiratory pressure therapy. Trans-oesophageal echocardiography revealed myocardial contusion and tricuspid valve rupture. Dobutamine improved left ventricular function and ejection fraction resulting in an immediate improvement in arterial oxygenation and saturation. Tricuspid injury and the diagnosis of myocardial contusion are discussed. The case highlights the importance of a non-pulmonary mechanism of hypoxaemia.
Accidents, Traffic↗
Recall of intraoperative events after general anaesthesia and cardiopulmonary bypass.
We wished to identify patients able to recall intraoperative events after general anaesthesia involving cardiopulmonary bypass (CPB). A balanced anaesthetic technique consisting of benzodiazepines, low dose fentanyl (15.9 +/- 8.5 micrograms.kg-1) and a volatile agent was employed. Perioperative recall was sought utilizing a structured interview on the fourth or fifth postoperative day. During 20 mo 837 patients underwent CPB. Seven hundred patients (84%) were able to respond to a structured postoperative interview. A detailed chart review was performed in patients with recall and in 60 randomly selected patients without recall. Eight patients (1.14%) reported recall of intraoperative events. We were unable to identify any differences between the two groups with respect to narcotic, benzodiazepine dosage or usage of inhalational agents. The incidence of recall in patients undergoing cardiac surgery was less in our group than previously reported. It is, however, higher than the 0.2% incidence recently reported in patients undergoing non-cardiac surgery. This is probably due to patient characteristics and intraoperative factors which make it difficult to avoid periods of relatively light anaesthesia during cardiac surgery.
Adult↗
Blunt thoracic trauma: anaesthesia, assessment and management.
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Anesthesia↗
Perioperative cardiovascular complications associated with blunt thoracic trauma.
The purpose of this study was to examine the frequency and importance of intraoperative mortality, arrhythmias and hypotension in the presence of thoracic trauma and to determine the effect of myocardial contusion on these perioperative complications. Over a two-year period patients with evidence of blunt thoracic injury who required surgery within 24 hr of admission were studied. The anaesthetist filled in a questionnaire on intraoperative events. Patients were also studied for the presence of myocardial injury with radionuclide angiography (RNA), at autopsy or at thoracotomy. Two hundred and one patients were studied. The intraoperative and overall mortality was 7.9% and 22.9% respectively. Of the operating room survivors the incidence of intraoperative arrhythmias and hypotension was 3.8% and 26.5% respectively. Only 5.9% of patients had a suspected or confirmed myocardial contusion. Patients were divided into two groups, those without myocardial injury were designated Group I, while those with myocardial contusion were designated Group II. The Group II patients had a greater severity of injury and intraoperative mortality (54.4%) than those in Group I (4.6%) P < 0.05. Intraoperative deaths were attributed to, with one exception, non-cardiac causes. There were no differences in the incidences of arrhythmias and hypotension between patients with-or without myocardial injury surviving the operating room. All patients with blunt thoracic injury may develop intraoperative arrhythmias or hypotension.
Adult↗