FEASIBILITY OF CONDUCTING CARDIOVASCULAR OUTCOME RESEARCH IN AUSTRALIAN GENERAL PRACTICE: RESULTS FROM THE ANBP2 PILOT STUDY

1. The present study aimed to determine the feasibility of conducting a 5 year cardiovascular outcome trial of the treatment of 6000 elderly hypertensive patients in Australian general practices. 2. General practitioners (GPs) were invited to participate by mail and personal follow-up. Patient records were reviewed to identify subjects for a blood pressure (BP) screening programme. Blood pressure was measured on three occasions and eligible subjects were included if the average BP was 160 mmHg systolic or 90 mmHg diastolic if systolic BP was 140 mmHg. 3. Seven hundred and forty-one GPs were approached and 89 were enrolled in the study (12% of mail invites and 75% of those receiving a personal contact). In 16 practices where screening was completed, 82 000 records were reviewed to identify 4% patients eligible for screening. Twenty-two per cent of eligible subjects attended screening. Of 1938 subjects screened, 180 (9%) had BP 5=160/90 mmHg. Forty-seven percent of subjects (n = 916) were receiving antihypertensive therapy and 184 (20%) were withdrawn from therapy. One hundred and sixteen (63%) of these subjects had BP return to study entry levels within 6 weeks. Fifty-seven newly diagnosed and 81 previously treated subjects were randomized (7% of the screened population). 4. Based on the high participation rate of GPs, the response rate of patients to attend a BP screening programme and the 7% randomization to screening ratio for entry into the study, the ANBP2 pilot study has demonstrated that it is feasible to recruit subjects from Australian general practices to a cardiovascular outcome trial.     

Relation between magnesium and potassium concentrations in myocardium, skeletal muscle, and mononuclear blood cells.

Potassium and magnesium were measured in 26 cardiac surgery patients (right atrial appendage), 23 autopsy subjects (right atrial appendage, left ventricular free wall, and skeletal muscle), and 9 healthy volunteers (mononuclear blood cells) to determine whether there was a relation between these two ions in the tissues measured. In the cardiac surgery patients, the potassium and magnesium concentrations were 46.35 +/- 3.89 and 4.40 +/- 0.58 (mean +/- SD, mumol/g wet weight tissue), respectively, and were significantly correlated (r = 0.54, P = 0.005). In the autopsy group, the respective concentrations were: for right atrial appendage, 30.54 +/- 10.18 and 3.66 +/- 0.70 mumol/g (r = 0.38, P = 0.14); left ventricular free wall, 60.69 +/- 17.93 and 7.74 +/- 1.73 mumol/g (r = 0.92, P = 0.0001); and skeletal muscle, 93.05 +/- 20.49 and 8.64 +/- 2.06 mumol/g (r = 0.91, P = 0.0001). In the healthy volunteer group, the results for potassium and magnesium in mononuclear blood cells were 42 +/- 9.9 and 3.99 +/- 0.70 fmol/cell, respectively (r = 0.94, P = 0.0001). Thus, potassium and magnesium concentrations were significantly correlated in all the tissues measured.     

Visual acuity estimates in noncommunicative elderly persons

The acuity card procedure has been shown to provide reliable grating acuity estimates in pediatric patients. The current study was conducted to determine the usefulness of this procedure in another group of persons in whom conventional acuity measurements are not possible, ie, nursing home residents who suffer from dementing disorders. Binocular visual acuity estimates were obtained in 13 cognitively impaired nursing home residents. Test sessions took 20-30 min each. Both test-retest agreement and inter-observer agreement of Teller Acuity Card (TAC) acuity estimates were good (within 0.5 octave for all residents), demonstrating that this procedure yields reasonable acuity estimates in noncommunicative nursing home residents. The authors stress the potential of this tool for nursing home administrators as well as for researchers.     

Influence of metoprolol and cilazapril on blood pressure and on sleep apnea activity.

Up to 50% of hypertensive men are subject to sleep apnea (SA). With a prevalence in men of up to 10%, SA is a common illness and hypertension (HT) one of its early symptoms. It is important to have available a drug treatment that will effectively control blood pressure (BP) without exacerbating symptoms of SA. Twelve patients with SA and HT were investigated in a double-blind, comparative trial. Patients were randomly allocated to either metoprolol (M) 100 mg daily or cilazapril (C) 2.5 mg daily. Polysomnographic measurements under standardized conditions including intraarterial BP monitoring were taken on two consecutive nights each before and after the 1-week treatment. Values in the M group were (mean +/- 95% CI) systolic BP 161 +/- 2.1 vs. 148 +/- 2.2 mm Hg (p less than 0.01); diastolic BP 98 +/- 1.8 vs. 93 +/- 1.8 mm Hg (p less than 0.01); and HR 73 +/- 1.2 vs 65 +/- 1.1 beats/min (p less than 0.01). Corresponding figures for the C group were systolic BP 140 +/- 2.1 vs. 127 +/- 2.1 mm Hg (p less than 0.01); diastolic BP 95 +/- 1.7 vs. 78 +/- 1.7 mm Hg (p less than 0.01); and HR 82 +/- 1.1 vs. 79 +/- 1.2 beats/min (p less than 0.01). Whereas C reduced both BP and HR in all sleep phases, M produced no changes during REM sleep. SA activity was 45 (range 15-91) vs. 34 (range 2-57) apneas per hour of sleep in the M group and 54 (range 21-84) vs. 40 (range 8-72) apneas per hour in the C group (p less than 0.01). There were no changes in total sleep time or in the proportions of non-REM to REM sleep. Both M and C reduce nocturnal BP in SA patients, but the effect of C is seen in all sleep phases. C has a more favorable effect on the disturbed nocturnal blood pressure of SA patients.     

Experimental studies on the recovery of anesthetic gases]

The volatile anesthetic agents halothane, enflurane, and isoflurane are chlorofluorocarbons (CFC) and contribute to ozone depletion. Although the contribution is small, its importance is rising, as technical CFCs will be phased out according to the Montreal protocol (1987) and the London conference (1990) by the year 2000. Alternative procedures and CFC-free volatile agents such as des- and sevoflurane do not contribute to depletion of the ozone layer, but will not replace standard methods using volatile anesthetic agents in the near future. METHODS. In an experimental setup, we filtered anesthetic waste gases from scavenging systems of rebreathing circles by activated carbon filters. The filtered substances were desorbed by a heat chamber and condensed in a cold trap. RESULTS. By this method, it was possible to retrieve 50%-60% of the applied gases. Gas chromatographic analysis showed halothane containing traces of pollutants and isoflurane and enflurane as pure substances. DISCUSSION. The retrieval of anesthetic waste gases is easy; no sophisticated technical equipment is necessary. Purity of substances could make recycling possible and offer a method to avoid environmental pollution by volatile anesthetics.