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Biomedical subjects

A Dyson

Publications and source records attributed to A Dyson.

At least 19 recordsLinked to original sources

A comparison of two methods for identifying surgical site infections following orthopaedic surgery.

Many infection control practitioners (ICPs) dedicate a significant amount of time and resources to surveillance of surgical site infections (SSIs). Alternative surveillance methods need to be explored to reflect the changes to the healthcare system and the increasing economic constraints placed on infection control units. This study was undertaken to compare two methods of identifying SSIs in orthopaedic surgery. Surveillance data collected routinely by ICPs was compared with data obtained from the International Classification of Disease, 9th Revision, Clinical Modification (ICD-9-CM) coding in the medical record. Concordant results between the two methods were obtained. The use of ICD-9-CM coding, as stored in hospital patient administration system databases, has the ability to enhance routine surgical site surveillance programmes. These systems can be used as the basis for screening large data sets for SSIs and identifying where SSIs resulted in patient re-admission. A reduction in the duplication of data and time spent by the ICP on the collection of information for surveillance purposes can be achieved.

Forms and Records Control↗

Rapidity and accuracy of tracheal intubation in a mannequin: comparison of the fibreoptic with the Bullard laryngoscope.

Successful tracheal intubation with the flexible fibreoptic bronchoscope requires a certain amount of skill which is acquired by practice. It has been suggested that the new Bullard laryngoscope may be mastered more easily. To determine if learning was superior with a flexible fibreoptic or the Bullard device, the ease of tracheal intubation with both devices was compared by first-year anaesthetic residents, using a mannequin modified to make intubation difficult. The Bullard laryngoscope was as easy to master as the flexible fibreoptic device, but passage of the tracheal tube took longer. Both devices require a similar amount of practice.

Anesthesiology↗

Esmolol attenuates cardiovascular responses to extubation.

Changes in heart rate and systolic blood pressure were measured during extubation and emergence from anesthesia in 40 ASA physical status I and II patients in a double-blind study to assess the effect of three doses of esmolol (1, 1.5, and 2 mg/kg) given as a bolus 2 min after reversal of neuromuscular blockade. Heart rate (P less than 0.01), systolic blood pressure (P less than 0.02), and rate-pressure product (P less than 0.01) increased significantly during extubation of the control group. All doses of esmolol attenuated the increases in heart rate, but 1 mg/kg was insufficient to control the increase in systolic blood pressure. Doses of 1.5 and 2 mg/kg controlled both systolic blood pressure and heart rate, but the larger dose produced significant decreases in systolic blood pressure.

Adolescent↗

Successful difficult intubation. Use of the gum elastic bougie.

The reliability of two signs of tracheal placement of a gum elastic bougie was studied. These signs were clicks (produced as the tip of the bougie runs over the tracheal cartilages) and hold up of the bougie as it is advanced (when the tip reaches the small bronchi). Ninety-eight simulated and two genuine Grade 3 difficult intubations were attempted with the aid of a gum elastic bougie. Seventy-eight tracheal and 22 oesophageal placements of the bougie resulted. No clicks or hold up occurred with the bougie in the oesophagus. Clicks were recorded in 89.7% of tracheal placements of the bougie. Hold up at between 24-40 cm occurred in all tracheal placements. We conclude that these signs are reliable and that they should be taught as part of any difficult intubation drill in which the gum elastic bougie is used.

Adult↗

An assessment of postoperative oxygen therapy in patients with fractured neck of femur.

Arterial oxygen tension was studied in sixty patients with fractured neck of femur. The mean preoperative arterial oxygen tension was 63.7 mmHg (SD 12.8). Half of the patients received nasal oxygen for five days postoperatively. In these patients, mean arterial oxygen tension was greater at all times than preoperative values, and exceeded values in those not receiving oxygen in whom no change in oxygen tension occurred until an increase on the fifth postoperative day.

Aged↗

Inspired oxygen and nitrous oxide concentrations in volunteers during nitrous oxide sedation with a Hudson mask.

Ten volunteers were given varying ratios of oxygen and nitrous oxide at 4, 6 and 8 litres per minute using a Hudson mask delivery system. Maximum and minimum inspired oxygen concentrations, maximum inspired nitrous oxide concentrations and end tidal carbon dioxide concentrations were measured using the Datex Cardiocap CCI-104 monitor. Although pharyngeal oxygen fraction varies with the Hudson mask because the inspiratory flow exceeds the entrainment of the mask by a variable amount during much of the cycle, at 8 litres/minute flow with a ratio of 3 to 5, oxygen to nitrous oxide, safe levels of oxygen were delivered (range of means 26-31%) with basal nitrous oxide levels (mean maximum inspired N2O, 34%). When nitrous oxide sedation is used clinically, nitrous oxide must be used with consideration of safe oxygen levels. This study did not detect unsafe pharyngeal oxygen levels in the ratios investigated, where the maximum delivered nitrous oxide concentration was 75%.

Humans↗

Tracheal tube cuff pressure. Clinical use of the Cardiff Cuff Controller.

Seventy-one adult patients (31 male, 40 female) who presented for surgery underwent orotracheal intubation with Portex Blue Line standard cuff disposable tubes (9-mm for males, 8-mm for females). The tracheal tube cuff was inflated by a trained assistant using a syringe and the initial cuff pressure measured; the minimum cuff pressure required to prevent respiratory gas leakage was also measured and the cuff pressure maintained above this pressure throughout the operation by means of the Cardiff Cuff Controller. Initial cuff pressure values averaged 11.9 kPa for males and 13.5 kPa for females compared with minimum cuff pressure values of 5.2 and 1.2 kPa, respectively. The differences between initial and minimum pressures were statistically highly significant (p much less than 0.001). It is concluded that the present method of inflation may lead to gross overinflation of tracheal tube cuffs and that cuff pressure monitoring may be performed simply by means of an electropneumatic controller. The difference in minimum cuff pressure between males and females suggests that the difference in tracheal size between the sexes is greater than the 9-mm to 8-mm difference in tracheal tube size.

Adult↗

Teaching medical ethics symposium. Medical ethics in Manchester.

Manchester's multi-disciplinary approach to medical ethics combines established methods and new initiatives. There is a longstanding Medical Group and also, plans are evolving for the inclusion of medical ethics teaching in the undergraduate curriculum, the start of an MA in Health Care Ethics in October 1987 and the establishment of the Centre for Social Ethics and Policy to act as a focus within the university for research and study in a wider context.

Curriculum↗