An evaluation of factors influencing the assessment time in a nurse practitioner-led anaesthetic pre-operative assessment clinic.

Elective patients undergoing anaesthetic pre-operative assessment are usually allocated the same period of time with a nurse practitioner, leading to potential inefficiencies in patient flow through the clinic. We prospectively collected data on 8519 patients attending a pre-operative assessment clinic. The data set were split into derivation and validation cohorts. Standard multiple regressions were used to construct a model in the derivation cohort, which was then tested in the validation cohort. Due to missing data, 2457 patients were not studied, leaving 5892 for analysis (3870 in the derivation cohort and 2022 in the validation cohort). The mean (SD) pre-operative assessment time was 46 (12) min. Age, ASA physical status, nurse practitioner and surgical specialty all influenced the time spent in pre-operative assessment. The predictive equations calculated using the derivation cohort, based on age and ASA physical status, correctly estimated duration of consultation to within 20% of the maximum predicted time in 74.2% of the validation cohort. We conclude that if age and ASA physical status are known before the pre-operative assessment consultation, it could allow appointment times to be allocated more accurately.

Contraceptive counselling and social representations: a qualitative study.

BACKGROUND: Contraceptive use is a complex issue and several studies have been conducted in an effort to understand user behaviour. It is of interest to explore the representations of professionals who give advice on contraception, since their views could have an impact on contraceptive use. METHODS: Individual in-depth interviews of 65 healthcare professionals likely to provide contraceptive advice to patients at a Swiss maternity unit. RESULTS: 83% of healthcare professionals interviewed were favourable to contraception in general while being highly critical of its practical efficacy. The methods most often spontaneously cited were oral contraceptive pills, male condom, intrauterine devices and hormonal implants. Theoretically, all methods should be proposed during contraceptive counselling but in practice interviewees have different social representations of user groups and associate them with specific contraceptive methods. Personal experience appears to play a bigger role than scientific knowledge. CONCLUSIONS: The counsellor's social representations probably play an important role in determining user behaviour. These representations should be taken into consideration in the training of healthcare professionals in this field.

A case report on acute severe hyponatraemia following parathyroid surgery for primary hyperparathyroidism-A rare but life threatening complication.

INTRODUCTION: Parathyroidectomy is a common operation, which is well tolerated and associated with low morbidity. Patients are usually discharged within 24hours of surgery. Severe postoperative hyponatraemia is a rare complication which can cause significant morbidity including seizure, coma, respiratory arrest and even death. PRESENTATION OF CASE: We present two patients with clinically significant hyponatremia resulting in seizures and collapse within 24hours after parathyroidectomy, an unreported complication following surgery for primary hyperparathyroidism. One patient required support on the High Dependency Unit and both were treated with fluid restriction which resulted in correction of their electrolyte balance. DISCUSSION: We believe this was caused by the relative inability to secrete a water load after surgery and non-psychogenic polydipsia. Preoperatively, neither patient was prescribed any routine medications nor did they have any risk factors for hyponatremia. Both had normal preoperative sodium levels. It is usual practice is to advise patients to increase oral water intake when they are hypercalcaemic. The aim of parathyroidectomy is to treat hypercalcaemia by stopping excess PTH secretion from abnormal parathyroid glands. These patients continued to follow this advice after surgery when they were eucalcaemic after their operation and because they were thirsty. The patients drank several litres of water in 12-24hours after surgery. We believe that this may have contributed to this complication. CONCLUSION: Healthcare professionals need to be aware of this complication and patients should be advised to restrict intake of free water after surgery.

Adverse effects of general anaesthetics.

This review deals with the adverse reactions associated with general anaesthetic agents in current use. These reactions fall into 2 categories; those which are more common, predictable and often closely related, and those which are rare, unpredictable and carry a high mortality. Both inhalational and intravenous anaesthetic agents affect the central nervous and cardio-respiratory systems in a dose-related manner. Neuronal inhibition results in decreasing levels of consciousness and depression of the medullary vital centres which can lead to cardiorespiratory failure. Both groups of agents have some depressant effect on the myocardium and vascular smooth muscle leading to a fall in cardiac output and hypotension. Centrally-mediated respiratory depression is common to both groups and the inhalational agents have a direct effect on lung physiology. The most important idiosyncratic reactions to the volatile agents are malignant hyperpyrexia and 'halothane hepatitis'. Malignant hyperpyrexia has an incidence of 1:12,000 with a mortality of about 24%. It is triggered most often by halothane together with suxamethonium. Post halothane hepatic necrosis is rare. Evidence points to 2 distinct syndromes; direct toxicity from the products of reductive metabolism, and a more serious illness, immunologically mediated via haptens formed by liver proteins and the products of oxidative metabolism. Prolonged nitrous oxide exposure can cause bone marrow depression and life-threatening pressure effects by expansion of air-filled spaces within the body. The idiosyncratic reactions to the intravenous agents include anaphylactoid reactions (which are rare) and triggering of acute porphyria. Etomidate is immunologically 'clean', but it inhibits cortisol synthesis.

Medical office automation integrated into the distributed architecture of a hospital information system.

Patient histories, discharge summaries, and medical consultant reports are made up of written texts. Therefore, the gathering and archiving of these texts in machine-readable form has many characteristics of computer-based medical records. In Geneva, approximately 1,540 PCs are connected to the Hospital Information System DIOGENE 2, with the possibility of accessing all the functions offered by the system without losing any of their MS-DOS word processing capabilities. The UNIDOC system, presented in this paper, takes all these features into account, a real marriage of technologies between the MS-DOS environment and the distributed client-server architecture. The INGRES database management system supports the entire archiving process of the medical patient texts, structured by prelabelled paragraphs and automatically indexed. Both the quality and accessibility of the records are enhanced, while the archiving capacity is neither too limited nor too expensive.

Effectiveness of preoxygenation in morbidly obese patients.

The time taken for the oxygen saturation (SpO2) to decrease to 90% after preoxygenation was studied in six morbidly obese patients and six matched controls of normal weight. During apnoea the obese patients maintained Spo2 greater than 90% for 196 (SD 80) s (range 55-208 s), compared with 595 (SD 142) s (range 430-825 s) in the control group (P less than 0.001). One patient in the obese group had desaturation before the onset of complete relaxation and tracheal intubation, without complications. Bedside lung function tests were not significantly different between groups and cannot be used as a predictor of the effectiveness of preoxygenation.

Effectiveness of continuous positive airway pressure to enhance pre-oxygenation in morbidly obese women.

Morbid obesity is associated with a reduction in time to desaturate during apnoea following standard pre-oxygenation and induction of anaesthesia. We have compared the effects of using 7.5 cmH2O of continuous positive airway pressure (CPAP) for pre-oxygenation with a standard technique using a Mapleson A breathing system, in 20 morbidly obese women. In a prospective, open, randomised trial, we measured the time taken to desaturate to 90% from time of giving a succinylcholine bolus as part of a rapid induction of anaesthesia. All patients received 3 min pre-oxygenation prior to induction. Tracheal intubation was confirmed and all patients kept apnoeic until oxygen saturation decreased to 90%. No statistically significant difference in mean time to desaturate to 90% could be demonstrated in the CPAP group compared to the Mapleson A group (240 s and 203 s, respectively). A brief period of lower mean heart rate in the CPAP group was the only statistically significant difference in cardiovascular parameters. There was no significant difference in the volume of gastric gas after induction between groups.

Pre-oxygenation--how long?

Pre-oxygenation was studied in 12 fit volunteers and 20 patients using an oxygen flow of 8 litres/minute delivered from a standard anaesthetic machine via a Magill or Bain breathing attachment. End-tidal nitrogen concentrations of 4% or less were achieved within 3 minutes; the fastest times were achieved using the Magill breathing system when the reservoir bag was filled with oxygen prior to application to the face. Gas-tight fits of face masks on patients were found to be essential.

Comparison of infusion rates of three i.v. anaesthetic agents for induction in elderly patients.

We have compared the effect of different rates of injection of 2.5% thiopentone, 0.5% methohexitone and 0.2% etomidate for induction of anaesthesia in 90 premedicated, elderly patients. The agents were administered by infusion pump at rates of 1200 ml h-1, 600 ml h-1 and 300 ml h-1, respectively until anaesthesia was induced as judged by loss of verbal contact with the patient. The times for induction were significantly greater with the slower infusion rates (thiopentone 41 s, 57 s and 91 s (P < 0.001); methohexitone 44 s, 62 s and 84 s (P < 0.01); etomidate 48 s, 59 s and 87 s (P < 0.001)). The doses were significantly smaller (P < 0.001) with the slower infusion rates for all three agents (thiopentone 5.0, 3.7 and 2.8 mg kg-1; methohexitone 1.00, 0.75 and 0.56 mg kg-1; etomidate 0.26, 0.15 and 0.11 mg kg-1). For each drug there was no significant difference in induction characteristics, oxygen saturation, heart rate or mean arterial pressure, at the different infusion rates.

Infusion of propofol to identify smallest effective doses for induction of anaesthesia in young and elderly patients.

We studied 110 patients older than 60 yr or aged 18-50 yr as separate groups in two stages to identify the smallest effective doses of propofol for induction of anaesthesia. In the elderly patients, in stage 1, at infusion rates of 25, 50 or 100 mg min-1 the mean (SD) doses administered were propofol 0.82 (0.14) mg kg-1, 1.22 (0.24) mg kg-1 and 1.65 (0.60) mg kg-1 and the induction times 140.1 (21.9) s, 103.2 (23.5) s and 69.4 (10.0) s, respectively. In stage 2, after induction with a fixed dose of 0.82 mg kg-1 as a bolus over 5 s or as an infusion at 25 mg min-1, the times for induction were 38.5 (14.0) s and 144.5 (36.6) s, respectively. In the young patients, at induction rates of 33.3, 50, 100 or 200 mg min-1, the doses administered were propofol 1.36 (0.28) mg kg-1, 1.46 (0.12) mg kg-1, 1.85 (0.43) mg kg-1 and 2.39 (0.50) mg kg-1 and the induction times 145.0 (25.4) s, 120.0 (18.4) s, 80.2 (19.2) s and 54.5 (10.4) s, respectively. In stage 2, a fixed induction dose of 1.46 mg kg-1 resulted in induction times of 35.0 (8.5) s and 134.0 (26.8) s, respectively. In stage 2 of each age group, induction was achieved with smaller doses than those recommended previously and there was no difference in the number of patients in whom induction of anaesthesia was successful or in the measured cardiorespiratory variables between the two induction regimens. This suggests the latter effects are caused by the dose administered and not the rate of administration.

[Computer alert and quality of care: application to the surveillance of hospital infections]. / Alertes informatiques et qualité des soins: application à la surveillance des infections hospitalières.

The Centre Informatique of Geneva University Hospital is developing, in the environment of its hospital information system, DIOGENE, a computerized alert system for surveillance of hospital infections. This hospital information system is based on an open distributed architecture and a relational database system, and covers many medical applications. This environment allows the development of alerts useful for detecting patients at risk. The alerts offer to clinicians a mean to control their efficacy in patient care. They are a new application of telematics for surveillance in clinical epidemiology, and are a tool for quality assurance. Two examples of alerts established for hospital infection control activities are presented. The first alert systematically detects all cases of patients colonized by or infected with methicillin-resistant Staphylococcus aureus (MRSA). The second alert helps to organize prospective surveillance of bloodstream infections in order to identify some risk factors for infection and propose preventive measures.