HIV/AIDS and childbirth: a feminist midwife's view

This paper explores the impact that the presence of the Human Immunodeficiency Virus has had on the care of pregnant and childbearing women in Victoria and on my professional life as a midwife in private practice and a midwife educator. It provides an overview of my personal experience and discusses how the issues associated with HIV/AIDS have gradually infiltrated the area of midwifery care in our hospital system. The prejudices and practices of the dominant patriarchal medical system have resulted in women being oppressed and controlled in pregnancy and labour in institutions that are supposed to be there to serve their needs.

A second look at the effects of supportive follow-up on smoking cessation

In 1982 a report in CMAJ (1982; 126: 127-129) indicated that the addition of supportive follow-up appointments in a family practice increased the 6-month cigarette abstinence rate from 12% to 23%. We reanalysed the data by means of recognized standards for treatment success and found little evidence that the treatment had any reliable effect on attempts to quit that lasted at least 3 months: 8.5% and 4.8% of the groups with and without supportive follow-up respectively abstained for more than 3 months. We discuss a problem of the experimental design (longer evaluative follow-up for the control group than for the treatment group) and cost-benefit issues.

A reappraisal of the relationship between arachnoid cysts of the middle fossa and chronic subdural haematoma

It has been increasingly recognised that patients with arachnoid cysts of the middle fossa appear more susceptible to the development of subdural haematomas. Seven patients with arachnoid cysts of the middle fossa and associated subdural haematomas are presented. Intra-cystic haemorrhage, masking the presence of an arachnoid cyst on computed tomography (CT) is highlighted. Repeat of CT scanning in young patients with subdural haematomas in the absence of severe trauma is recommended. Two theories are proposed to account for the observed susceptibility to the development of subdural haematomas in these patients.

A non-linear regression program in BASIC for estimating Km and Vmax

This paper gives a program in BASIC for calculating the kinetic parameters Km and Vmax for an enzyme reaction from a set of paired values of reaction velocity at given substrate concentrations. An initial estimate of the two parameters is made using a weighted linear regression, these values are then used in an iterative process to fit the data to the Michaelis-Menten equation and give final values of Km and Vmax with their associated standard errors.

[Electrocardiographic anomalies in subarachnoid hemorrhage]

An electrocardiographic study was undertaken in 100 patients with subarachnoid haemorrhage to try and establish a relationship between the clinical state of the patient and the ECG abnormalities. Cerebral angiography was performed in 95 cases showing 1 or more aneurysms in 68 cases and an angioma in 6 cases. Twenty one patients had no cerebrovascular abnormality. Routine ECGs were recorded on admission and were abnormal (Lipman and Massie's criteria) in 80 p. 100 of cases. The commonest changes were T-wave inversion (34 cases), bradycardia (32 cases), abnormal U-waves (28 cases) and prolongation of the Q-T interval (21 cases). Only 2 patients had giant T waves of normal polarity. Intraventricular conduction defects were more common (12 cases) than atrioventricular block (3 cases). Ten patients had sinus tachycardia and ventricular extrasystoles were observed in 5 cases. The patients were divided into two groups according to severity of their clinical state: Group A (52 patients) without changes in the level of consciousness, and Group B (48 patients) with disturbed levels of consciousness. The incidence of bradycardia and T-wave inversion in the two groups was compared by the Chi-squared test. Bradycardia was commoner than T-wave inversion in Group A (52 p. 100 and 19 p. 100 respectively). This finding was the contrary to what was observed in Group B where 10 p. 100 of patients had bradycardia (p less than 0,0005) and 50 p. 100 had T-wave inversion (p less than 0,005). The ECG changes were of prognostic value. The survival rate in patients with T-wave inversions was 85,7 p. 100 (p less than 0,001). The presence and site of the cerebrovascular abnormalities were not related to the ECG changes and no correlations were found between electrolyte changes and the ECG appearances.(ABSTRACT TRUNCATED AT 250 WORDS)

[Anti-arrhythmic effects of mexiletine]

Mexiletine was used in 12 patients. Serum drug levels and the antiarrhythmic effects were studied in a therapeutic protocol comprising an initial intravenous administration (3,5 mg/Kg over 10 mins, then 450 mg in 5 hours) followed by oral administration (200 mg eight hourly). The serum drug levels of Mexiletine were high (1,46 +/- 0,47 microgram/ml) as from the first hour in all patients, and remained constant during intravenous administration (average: 1,59 +/- 0,72 microgram/ml). On oral therapy the average mexiletine level was 1,18 +/- 0,21 microgram/ml with two lows (1,02 microgram/ml) six to eight hours after the ingestion of the 200 mg gelules. Ventricular extrasystoles completely regressed after the initial rapid intravenous injection in 7 out of the 12 patients (58,3 p. 100) and this efficacity was maintained throughout the trial. In two patients with low serum mexiletine levels at the end of oral therapy (less than 1 microgram/ml), ventricular extrasystoles were much less frequent during the intravenous phases but reappeared during oral therapy. The clinical, electrocardiographic and hemodynamic tolerance was good (withdrawn in only one patient). The dose should be adapted to the patient's weight and hemodynamic status. When ineffective, the serum mexiletine level can be estimated and when less than 1 microgram/ml, the dose may be increased, in particular by adjusting oral dosage to 200 mg six hourly.

[Hemodynamic effects of percutaneous trinitrin]

The haemodynamic effects of nitroglycerin (NG) ointment were studied in 13 patients, 6 with congestive cardiac failure. After two basal measurements 30 minutes apart, heart rate (HR), right atrial pressure (RAP), pulmonary artery diastolic pressure (PADP), mean systemic arterial pressure (MAP) and cardiac index (CI) were measured every fifteen minutes for one hour, and every hour for five hours. Two patients were given one capsule, and nine patients two capsules of 10 mg NG, applied on separate 15 cm2 skin patches and covered with plastic dressings. There was a slight fall of 1,9% in HR from the 45th minute to the 5th hour. A large increase in HR was only observed in one patient who had low basal filling pressures. A moderate decrease in MAP was recorded (4,6%, p less than 0,05) The greatest changes were observed in RAP which decreased (p less than 0,05) from the 30th to the 60th minute with a maximum at the 45th minute (17,4%) and in PADP which fell from the 15th minute to the 5th hour (p less than 0,005) with a maximum at the 120th minute (21,9%). Local tolerance was good. The systolic blood pressure did not fall below 90 mm Hg in any patient. A case by case analysis showed falls of RAP and PADP of over 20% in 10 and 9 patients respectively. The decrease in PADP was not proportional to the basal value but patients with the highest initial values had the least changes. A 20% fall in PADP was observed in only one of four patients with PADP of over 25 mm Hg at rest. A greater dose of NG might have had a greater effect in these patients. There was no significant change in CI, probably due to the stability of peripheral arterial resistances during the study. The value of this preparation of NG lies in its long duration of action. A fall in PADP of over 15% was observed up to the 150th minute, and persisted to a lesser degree up to the 5th hour. This makes it very suitable for the treatment of nocturnal angina as conventional antianginal delayed release nitrate derivatives usually have a shorter duration of action.

[Hemodynamic effects of mexiletine]

The haemodynamic changes caused by intravenous mexiletine were studied in 12 patients. Initially the drug was given rapidly at the rate of 3 mg/kg/min for 10 minutes and then slowly at a rate of 0,06 mg/kg/min for 30 minutes. The plasma Mexiletine level measured after 20 minutes was used to divide the series of patients into two groups: in Group A the level was over 0,7 g/ml (0,961 +/- 0,109 microgram/ml) whilst in Group B the level was only 0,547 +/- 0,101 microgram/ml. The mean aortic pressure, heart rate and left ventricular end diastolic volume did not vary significantly in the two groups. The left ventricular end diastolic pressure rose, and the cardiac index and the ejection fraction fell in Group A. The indices of left ventricular contractility fell in all patients of the start of the injection. This depression only persisted to the end of the injection in Group A. Mexiteline did not cause significant changes in post extrasystolic potentialisation in the 5 cases in which this phenomenon was studied.

[Importance of sequential atrioventricular pacing in obstructive myocardiopathy with atrioventricular block]

A case of atrioventricular block (AVB) complicating hypertrophic obstructive cardiomyopathy is reported and analysed with respect to the results of cardiac catheterisation. The installation of 2nd degree AVB was associated with an increase of the intraventricular pressure gradient from 36 to 128 mmHg. This aggravation was related to the lenghtening of diastole which lowered the aortic diastolic pressure and allowed a more forceful ventricular contraction with a reduction in the calibre of the intraventricular stenosis. The sudden lenghtening of diastole also led to an increased contractility of the following systole. In complete AVB the increased gradient was related to a reduction in ventricular volume secondary to the loss of atrial systole. The 33 mmHg pressure gradient disappeared when spontaneous atrial systole or an atrial systole provoked by sequential atrioventricular pacing preceded ventricular contraction. Sequential atrioventricular pacing would seem to be the most appropriate pacing technique in hypertrophic obstructive cardiomyopathy complicated by complete AVB.

[Antiarrhythmic action of disopyramide: a study of plasma levels]

The action of dysopyramide was studied in 13 patients, 11 with ventricular and 2 with supraventricular arrhythmias. The drug was given parenterally at first and then by mouth. The patients were monitored with an arrhythmia counter and the plasma levels of disopyramide measured throughout the treatment period. The plasma level was stable at about 4 micrograms/ml during the different phases. Toxic levels of 10 microgram/ml were observed in 1 patient in renal failure. The antiarrhythmic action was very effective (70% success), especially on the ventricular arrhythmias. Two of the four patients who failed to respond to treatment had low, non-therapeutic plasma levels. The dosage should be adapted with respect to the patient's weight and renal function.