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Biomedical subjects

B F Horan

Publications and source records attributed to B F Horan.

16 recordsLinked to original sources
PubMed2005

Crisis management during anaesthesia: hypertension.

BACKGROUND: Hypertension occurs commonly during anaesthesia and is usually promptly and appropriately treated by anaesthetists. However, its recognition is dependent on correctly functioning and calibrated monitors. If it is not diagnosed and/or promptly corrected, it has the potential to cause significant morbidity and even mortality. OBJECTIVES: To examine the role of a previously described core algorithm "COVER ABCD-A SWIFT CHECK" supplemented by a specific sub-algorithm for the management of hypertension occurring in association with anaesthesia. METHODS: The potential performance of this approach for each of the relevant incidents among the first 4000 reported to the Australian Incident Monitoring Study (AIMS) was compared with the actual management as reported by the anaesthetists involved. RESULTS: There were 70 reports of intraoperative hypertension among the first 4000 incidents reported to AIMS. Drug related causes accounted for 59% of all incidents. It was considered that, properly applied, this structured approach would have led to a quicker and/or better resolution of the problem in 21% of the cases. CONCLUSION: Once hypertension is identified and confirmed, its rapid control by the careful use of a volatile anaesthetic agent, intravenous opioids, or rapidly acting antihypertensives will usually avoid serious morbidity. If hypertension is unresponsive to the treatment recommended in the relevant sub-algorithm, an unusual cause such as phaeochromocytoma, carcinoid syndrome, or thyroid storm should be considered.

Algorithms↗
PubMed1997

Evidence-based medicine and anaesthesia: uneasy bedfellows?

The term "evidence-based medicine" first appeared in the medical literature in 1992 and is in widespread use today. It is timely to examine the concept's relevance to anaesthetic practice as well as the validity of the premises on which it rests. An important difference between anaesthesia and the specialties which treat disease is that in anaesthesia there is very little research done with real outcomes as its end-point. Surrogate or intermediate outcomes predominate as the end-points of anaesthetic research, which is a weakness when the results serve as the evidence on which to base clinical decisions. Furthermore, in interventions which require personal skill, dexterity or decision-making, caution must be exercised in assuming that equally good outcomes are achievable by all. Key members of the Cochrane Collaboration, among the most prominent advocates of evidence-based medicine, promote the belief that much valid scientific evidence is to be found in sources outside the peer-reviewed published literature. This assertion must be treated with caution. Furthermore, some techniques central to the search for the evidence on which to base practice, including meta-analysis and multicentre trials, are prone to errors through incorrect application. Evidence-based medicine appears to have less to offer anaesthesia than it does to the "treating" specialties.

Anesthesiology↗
PubMed1996

Deaths attributed to anaesthesia in New South Wales, 1984-1990.

The New South Wales Special Committee Investigating Deaths Under Anaesthesia classified 1503 deaths before full recovery from anaesthesia occurring between 1984 and 1990. 172 deaths were attributed to anaesthesia, including 11 in which the anaesthetic choice or management could not be criticized. In the remaining 161 an average of 1.8 errors per case were identified, the most frequent being inadequate preparation of the patient (in 72 cases), inadequate postoperative care (52 cases), the technique of anaesthesia chosen (44 cases) and overdose (43 cases). Death was most commonly attributed to anaesthesia in elderly patients (modal age group 70-79), in males (1.9:1) and was most commonly associated with abdominal and orthopaedic operations. Urgent non-emergency cases, 10% of the 1503 cases classified, constituted 26% of those deaths attributed to anaesthesia. One death attributable to anaesthesia occurred per 20,000 operations and the rate of such deaths was 0.44 per 100,000 population per annum.

Adolescent↗
PubMed1996

Urgent non-emergency surgery and death attributable to anaesthetic factors.

The Special Committee Investigating Deaths Under Anaesthesia in New South Wales classified 1503 deaths which occurred in the years 1984 to 1900 during, within 24 hours of, or as a result of anaesthesia. One hundred and seventy-two (11.4%) of these were attributed definitely, probably or jointly to factors under the anaesthetists' control. One hundred and forty-four (9.6%) of the 1503 deaths classified occurred in patients undergoing urgent non-emergency operations of which 45 (31.3%) were attributed to anaesthetic factors. A specialist anaesthetist either gave the anaesthetic or was present for part or all of it in 35 of these 45 cases. In 22 the hospital was a metropolitan teaching hospital. General anaesthesia was employed in 31 cases and major regional block (10 spinals and 4 epidurals) in the others. The commonest type of surgery was orthopaedic (26 cases), particularly for fractured neck of femur (20 cases). There were no deaths attributed to anaesthetic factors in cases of this degree of urgency in patients less than 16 years old. The factors under the anaesthetists' control most often identified as contributing to death were inadequate preparation for anaesthesia and surgery (18 cases, 12 of which were jointly attributed to the surgeon); inappropriate choice or application of technique (17); inadequate postoperative care (12 cases); and overdose (11 cases). If improved outcomes are to be achieved for patients having operations of this degree of urgency, greater attention must be paid to these aspects of their anaesthetic management.

Adolescent↗
PubMed1994

Mortality associated with anaesthesia in New South Wales, 1984-1990.

OBJECTIVE: To review deaths in New South Wales associated with anaesthesia from 1984 to 1990. DESIGN: The Special Committee Investigating DeathS Under Anaesthesia reviewed all deaths in NSW under anaesthesia or within 24 hours of anaesthesia in which complete recovery from anaesthesia did not occur. FINDINGS: The Committee reviewed 1503 deaths in some 3.5 million surgical procedures. In 60% the patient's death was considered to be inevitable and in 4% fortuitous. Factors under the control of the anaesthetist caused or significantly contributed to the fatal outcome in 172 cases (11%). Factors under the control of the surgeon caused or significantly contributed to the fatal outcome in 421 cases (28%). In 191 of the 421 deaths related to surgical factors and 11 of the 172 deaths related to anaesthetic factors, no better alternative procedure was considered possible and the procedures were properly performed. In only one death in a child under 10 years and in two obstetric fatalities was the anaesthetic management considered to have contributed to the outcome. Three quarters of the deaths were related to abdominal, cardiothoracic or vascular surgery, and 70% were related to emergency procedures. Male deaths outnumbered female 1.7:1. The mortality rate was 4.4 per 10,000 operations, with a male: female ratio of more than 2:1. Trauma in the 20-29 age group and vascular and cardiothoracic surgery in the 50-79 age group were mainly responsible for the sex difference in the number of deaths, but the difference was also seen in other surgical groups. CONCLUSIONS: From 1984 to 1990, deaths in which factors under the control of the anaesthetist caused or contributed to the fatal outcome occurred at a rate of 1 in 20,000 operations. This figure compares favourably with a rate of 1 in 5500 operations in NSW in 1960 and 1 in 10,250 operations in 1970.

Adolescent↗
PubMed1992

Significance of diastolic pulmonary artery pressure peaks.

We describe a patient undergoing elective surgery for treatment of an abdominal aortic aneurysm in whom an abrupt change in the contour of the pulmonary artery pressure (PAP) trace indicated the development of an intermediate (20 mm Hg) V wave in the pulmonary artery wedge pressure (PAWP) trace. As the PAP trace is displayed continuously, attention to its contour may allow for early detection of changes to the underlying PAWP trace.

Aged↗
PubMed1987

Acute cardiovascular responses to internal carotid artery occlusion during carotid endarterectomy and to the restoration of internal carotid flow.

Heart rate, central venous pressure, radial artery pressure and electrocardiograph were recorded in 14 patients undergoing carotid endarterectomy under general anaesthesia supplemented with fentanyl and halothane and muscle relaxation as required. Induction of anaesthesia was followed by a significant reduction in systolic arterial pressure and a rise in central venous pressure (CVP). Thereafter CVP did not vary significantly and heart rate did not change significantly at any stage. After internal carotid artery occlusion, mean systolic pressure at one minute, 143 (SD 17) mmHg, and three minutes, 160 (SD 27) mmHg, were both significantly higher than prior to occlusion, 132 (SD 17) mmHg (P less than 0.01 and P less than 0.002 respectively). Similar significant changes occurred in diastolic pressure after carotid occlusion (P less than 0.02 and P less than 0.002 respectively). The restoration of flow through the internal carotid artery in patients operated on without a shunt was associated with a significant reduction in mean systolic pressure. The mean systolic pressure at one minute, 145 (SD 20) mmHg, and three minutes, 135 (SD 19) mmHg, were both significantly lower than that before restoration of flow, 159 (SD 17) mmHg (P less than 0.02 and P less than 0.05 respectively). Changes in mean diastolic pressure in this group at these times, while in the same direction, were not significant. The observed hypertensive response to carotid occlusion may assist in preserving cerebral perfusion while the internal carotid artery is occluded, but may be hazardous for patients with ischaemic heart disease.

Aged↗
PubMed1985

The glass bead game.

Explore the source record for details and available documents.

Periodicals as Topic↗
PubMed1977

Haemodynamic responses to isoflurane anaesthesia and hypovolaemia in the dog, and their modification by propranolol.

In six dogs chronically implanted with flow and pressure transducers, equipotent inspired concentrations of halothane and isoflurane were determined as the minimum inspried concentration of each agent which would abolish an individual dog's response to paw clamping. In equipotent concentration, isoflurane (1.2%, SD 0.2%) caused less myocardial depression than halothane (1.0%, SD 0.1%). Dose-response studies were possible up to a mean inspired isoflurane concentration of 3.0%, both before and after propranolol 0.3 mg kg-1, i.v. After propranolol, sensitive indices of myocardial contractility were depressed at all concentrations of isoflurane, indicating a moderate degree of beta-receptor activation by isoflurane. The haemodynamic response to hypovolaemia during isoflurane anaesthesia was not modified by propranolol.

Anesthesia, Inhalation↗
PubMed1977

Haemodynamic responses to enflurane anaesthesia and hypovolaemia in the dog, and their modification by propranolol.

The haemodynamic responses to minimum equipotent concentrations of halothane and enflurane were compared in seven dogs. The haemodynamic responses to increasing concentrations of enflurane, and to induced hypovolaemia during enflurane anaesthesia, were studied in the same dogs, both before and after administration of propranolol 0.3 mg kg-1 i.v. In equipotent concentrations, enflurane caused marginally greater impairment of left ventricular function than halothane, and caused a dose-dependent reduction of arterial pressure, cardiac output and myocardial contractility. Following administration of propranolol, these haemodynamic effects of enflurane were marked, and withdrawal of 20% of estimated blood volume was tolerated poorly.

Anesthesia, Inhalation↗