Survey of the attitudes of British physicians to pacing.

OBJECTIVES--To assess how the opinions of cardiologists, physicians, and general practitioners on the indications for permanent pacing compare with published guidelines, and to determine whether resources, pacing experience, and position influence referral practices. DESIGN--Anonymous postal survey by questionnaire from St Bartholomew's Hospital, London and the King's Fund Institute, London. The questionnaire established the respondent's position, resources, and previous pacing experience. Eleven clinical and electrocardiographic situations were described and respondents were asked to decide on whether pacing was indicated. The responses received were compared with the guidelines provided by the 1984 American College of Cardiology/American Heart Association task force. PARTICIPANTS--The 630 members of the British Cardiac Society, 1370 randomly selected general physicians, and 2000 general practitioners. RESULTS--Patients with symptoms were more likely to be referred for pacing than symptom free patients regardless of underlying aetiology. In relatively symptom free patients the frequency with which pacing was recommended was low, even when it was unequivocally indicated on prognostic grounds. Failure to recommend pacing was unrelated to diagnostic facilities or referral difficulties. Respondents with pacing experience were more likely to recommend pacing. CONCLUSIONS--The physicians surveyed had a conservative approach towards recommending pacing. Most physicians were influenced predominantly by symptoms and the prognostic indications for pacing were not well appreciated.     

Exogastric neurilemmoma presenting as acute abdomen: Role of computed tomography in diagnosis

A case of subserosal gastric neurilemmoma is hereby presented. This reported case is unique in its clinical presentation including the appearance of acute abdomen and fever subsequent to unremarkable and uneventful upper gastrointestinal endoscopy. The tendency of neurilemmoma to cause mucosal ulceration with fistula formation probably led to this clinical presentation. The role of computed tomography in establishing diagnosis of exogastric tumor is emphasized.     

Adrenergic blockade blunts adenosine concentration and coronary vasodilation during hypoxia.

Myocardial hypoxia is thought to be an important stimulus for increasing interstitial adenosine concentration. The adenosine hypothesis of coronary control was investigated during steady-state hypoxia by making measurements of coronary venous and epicardial well adenosine concentrations in adrenergically intact dogs and in animals with alpha- and beta-receptor blockade. In the adrenergically intact group, hypoxia sufficient to lower coronary venous oxygen tension to 8 mm Hg increased coronary blood flow 243% from normoxic values. Both coronary venous and epicardial well adenosine concentrations were increased throughout the hypoxic period. In the adrenergically blocked group, hypoxia to a similar level of coronary venous oxygen tension produced an increase in coronary blood flow of only 75%, which was significantly less than in the adrenergically intact group (p less than 0.01). Coronary venous adenosine was only transiently elevated, and epicardial well adenosine was unchanged from control levels. In a separate group of alpha- and beta-receptor-blocked animals that received an infusion of L-homocysteine thiolactone during hypoxia, there was no difference in tissue S-adenosylhomocysteine levels compared with those of normoxic controls. It is concluded that much of the coronary vasodilation associated with systemic hypoxia is dependent on adrenergic activation and that adenosine may only play a role in sustained hypoxic vasodilation when adrenergic receptors are intact.     

When Is a Bispectral Index of 60 Too Low?: Rational Processed Electroencephalographic Targets Are Dependent on the Sedative-Opioid Ratio

Background: Opioids are commonly used in conjunction with sedative drugs to provide anesthesia. Previous studies have shown that opioids reduce the clinical requirements of sedatives needed to provide adequate anesthesia. Processed electroencephalographic parameters, such as the Bispectral Index (BIS; Aspect Medical Systems, Newton, MA) and Auditory Evoked Potential Index (AAI; Alaris Medical Systems, San Diego, CA), can be used intraoperatively to assess the depth of sedation. The aim of this study was to characterize how the addition of opioids sufficient to change the clinical level of sedation influenced the BIS and AAI.

Methods: Twenty-four adult volunteers received a target-controlled infusion of remifentanil (0-15 ng/ml) and inhaled sevoflurane (0-6 vol%) at various target concentration pairs. After reaching pseudo-steady state drug levels, the modified Observer's Assessment of Alertness/Sedation score, BIS, and AAI were measured at each target concentration pair. Response surface pharmacodynamic interaction models were built using the pooled data for each pharmacodynamic endpoint.

Results: Response surface models adequately characterized all pharmacodynamic endpoints. Despite the fact that sevoflurane-remifentanil interactions were strongly synergistic for clinical sedation, BIS and AAI were minimally affected by the addition of remifentanil to sevoflurane anesthetics.     

Morphology of corneal nerves in soft contact lens wear. A comparative study using confocal microscopy

The aim of this study was to evaluate corneal innervation in soft contact lens wearers using the Tomey Confoscan confocal microscope (40x/0.75 objective lens). Three distinct age- and sex-matched subject groups were involved, including extended soft (hydrogel and silicone-hydrogel) contact lens wearers, overnight soft (hydrogel) contact lens wearers, and non contact lens wearers. A number of variables were objectively measured, subjectively evaluated, or graded in order to investigate the distribution and morphology of corneal nerves. For most of the evaluated parameters, no statistically significant differences were found. However, qualitative observations showed noticeable differences in corneal nerve appearance among the different subject groups; the degree of corneal oedema was suggested as the main causative factor. In conclusion, neither the short-term (overnight wear) nor the long-term (12-month extended wear) soft contact lens wear appeared to affect the morphology and/or distribution of corneal nerves as viewed with confocal microscopy.