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Biomedical subjects

J R Stradling

Publications and source records attributed to J R Stradling.

At least 91 records · Page 5Linked to original sources
PubMed1991

Periodic movements of the legs during sleep associated with rises in systemic blood pressure.

We report the relationship between periodic leg movements during sleep and recurrent rises in systemic blood pressure in a patient with narcolepsy. The mean increase in systolic blood pressure following leg movements was 23%, which is of the same order as the rises seen in patients with obstructive sleep apnea. Following treatment with temazepam, the swings in blood pressure were unchanged despite considerably less electroencephalographic evidence of cortical arousal.

Alpha Rhythm↗
PubMed1990

Effect of adenotonsillectomy on nocturnal hypoxaemia, sleep disturbance, and symptoms in snoring children.

61 snoring children selected for adenotonsillectomy, mainly for recurrent tonsillitis, were compared with a matched group of 31 healthy children for symptoms of sleep apnoea, extent of sleep hypoxaemia, and amount of sleep disturbance. The studies were repeated six months postoperatively, and after six months in the healthy children. Preoperatively, 61% of the children had degrees of sleep hypoxaemia above normal and 65% had abnormally disturbed sleep. A questionnaire administered to the parents about their children showed abnormal patterns of answers about sleep problems daytime sleepiness, hyperactivity, aggression, learning difficulties, restless sleep, and odd sleeping positions. After adenotonsillectomy, the abnormal hypoxaemia, excessive sleep disturbance, and multiple symptoms almost resolved; a growth spurt also occurred.

Adenoidectomy↗
PubMed1990

Relation between systemic hypertension and sleep hypoxaemia or snoring: analysis in 748 men drawn from general practice.

OBJECTIVE: To establish whether a history of snoring or the degree of overnight hypoxaemia is an important independent predictor of systemic blood pressure. DESIGN: Prospective community based study of blood pressure in relation to overnight oxygen saturation, height, weight, and a questionnaire assessment of snoring, smoking, and alcohol consumption. Analysis was by multiple linear regression techniques and analysis of variance. SETTING: Small town outside Oxford, served by one group general practice of four partners. All measurements were made at home. SUBJECTS: The names of 836 men aged 35-65 were drawn at random from the general practitioners' age and sex register and the men then asked to participate; 752 (90%) agreed. MAIN OUTCOME MEASURES: Systolic, mean, and diastolic blood pressures and their association with age, obesity, alcohol consumption, cigarette consumption, snoring, and overnight hypoxaemia. RESULTS: Though systemic blood pressure correlated significantly with overnight hypoxaemia, this was due to the cross correlation with age, obesity, and alcohol consumption. No independent predictive effect of overnight hypoxaemia was found. Snoring was correlated with systemic blood pressure but not significantly so and also was not an independent predictor once age, obesity, and alcohol consumption had been allowed for. CONCLUSIONS: It is unlikely that snoring and sleep hypoxaemia from occult sleep apnoea are important causes of diurnal systemic hypertension when compared with age, obesity, and alcohol consumption. The increased prevalence of cardiovascular complications reported in snorers may be due to the confounding variable of obesity or to nocturnal rises in blood pressure that are not reflected in the daytime figures.

Adult↗
PubMed1990

The effect of acetazolamide on hypercapnic and eucapnic/poikilocapnic hypoxic ventilatory responses in normal subjects.

We have studied the effect of acetazolamide 500 mg bd for three days on ventilatory response to CO2 (HCVR) and hypoxia under both isocapnic and poikilocapnic conditions (isocapnic and poikilocapnic HVR) in five normal subjects. Although acetazolamide reduced calculated arterial pH (7.41 [SEM] 0.01 to 7.37 [SEM] 0.01: p less than 0.01) there was no significant change in either isocapnic HVR (with PetCO2 held at the post-drug resting level) or poikilocapnic HVR in terms of slope and ventilation at SaO2 = 80%. HCVR slope rose slightly (+1.82 [SEM] 0.43 to +2.2 [SEM] 0.29 l/min/mmHg: NS) and there was a significant increase in ventilation at Pet-CO2 = 50 mmHg (9.42 [SEM] 3.3 to 31.4 [SEM] 6.31/min: p less than 0.01). These findings are consistent with the claim that acetazolamide stimulates central chemoreceptors and inhibits peripheral chemoreceptors. Increased sensitivity to CO2 would reverse the suppressive effect of respiratory alkalosis on hypoxic ventilatory drive following rapid ascent to high altitude, and this probably accounts for the efficacy of acetazolamide in the prophylaxis of acute mountain sickness. However, inhibition of peripheral chemoreceptors may also result in symptomatic benefit by reducing sleep disturbance due to periodic breathing.

Acetazolamide↗
PubMed1990

Lack of effect of an inspiratory threshold load on plasma atrial natriuretic peptide levels.

1. After a run-in period, six healthy, recumbent, water-loaded male subjects breathed through an inspiratory threshold load for 90 min. To correct for prolonged recumbency, a similar protocol was followed on a separate control day, but without an inspiratory load. 2. A negative intrathoracic pressure of at least 30 cmH2O was required to overcome the threshold load. 3. Urine was collected every 30 min and analysed for sodium concentration. 4. Plasma samples were collected every 30 min and analysed for atrial natriuretic peptide concentration. 5. The inspiratory load had no effect on urine volume, urinary sodium excretion or plasma atrial natriuretic peptide levels.

Adult↗
PubMed1990

Ear involvement in the yellow nail syndrome.

Recognized features of the yellow nail syndrome include yellow nails, lymphedema, and pleural effusions. We report a patient with the additional feature of keratosis obturans, which may be a manifestation of this syndrome in the external ear.

Ear Canal↗
PubMed1990

The relationship between neck circumference, radiographic pharyngeal anatomy, and the obstructive sleep apnoea syndrome.

We have studied the predictive importance of neck circumference, obesity, and several radiographic pharyngeal dimensions for obstructive sleep apnoea (OSA), in 66 patients. OSA was quantified as the mean hourly number of greater than 4% dips in arterial oxygen saturation during sleep. Neck circumference (correlation coefficient (r) = 0.63, 95% confidence interval (C.I.) 0.46-0.76), obesity index (r = 0.54, 95% C.I. 0.39-0.69), hyoid position (r = 0.40, 95% C.I. 0.17-0.59), soft palate length (r = 0.31, 95% C.I. 0.08-0.51), and hard palate-to-spine angle (r = 0.29, 95% C.I. 0.04-0.49), correlated significantly with saturation dips in single regression analysis. In stepwise multiple linear regression analysis (saturation dip rate as the dependent variable), only neck size and retroglossal space were significant independent correlates (total r2 = 0.42, 95% C.I. 0.22-0.61, p less than 0.0001). We conclude that the relationships between general obesity, hyoid position, soft palate length, and OSA are probably secondary to variation in neck circumference.

Female↗
PubMed1988

Abnormal diurnal variation in salt and water excretion in patients with obstructive sleep apnoea.

1. In healthy individuals, sleep is associated with a fall in urine and sodium output. 2. Seven male patients with obstructive sleep apnoea exhibited a paradoxical rise in both urine and sodium output during the hours of sleep. 3. Continuous positive airway pressure applied via the nose abolished both the apnoea and the nocturnal rise in urine and sodium output, thereby restoring the diurnal pattern towards normal.

Adult↗
PubMed1988

Prediction of favourable responses to long term vasodilator treatment of pulmonary hypertension by short term administration of epoprostenol (prostacyclin) or nifedipine.

Eighteen patients with moderate to severe pulmonary hypertension were studied, nine with intracardiac shunts and nine without. The effects of an incremental infusion of epoprostenol (prostacyclin) (0.5-8 ng/kg per minute) or sublingual nifedipine (20-30 mg) were compared with the response to three months' treatment with oral nifedipine. Both epoprostenol and sublingual nifedipine caused a fall in pulmonary vascular resistance and pressure and a rise in cardiac output. Patients with intracardiac shunts had higher systemic blood flows than those without shunts. Exercise in the shunt group was accompanied by systemic desaturation and hyperventilation. Analysis of individual results showed that the size of the response was inversely related to the severity of the pulmonary vascular disease. A good long term response to nifedipine seemed to be as readily predicted by the resting control values for haemodynamic variables as by values after short term treatment. A favourable response was likely if the pretreatment mean pulmonary artery pressure was less than 50 mm Hg, the ratio of total pulmonary to systemic resistance was less than 0.7, or the ratio of mean pulmonary artery pressure to systemic artery pressure was less than 0.6. Short term vasodilator protocols may do harm. If such studies are carried out, an adequate dose range must be tried before the long term efficacy of an individual drug can be forecast.

Administration, Oral↗
PubMed1988

Do sleep studies contribute to the management of patients with severe chronic obstructive pulmonary disease?

To determine whether studies of breathing and oxygenation during sleep are clinically useful, we have assessed whether the detection of excess nocturnal hypoxemia in patients with chronic obstructive pulmonary disease (COPD) is of prognostic importance. Ninety-seven patients with COPD were followed for 32 to 108 (median, 70) months after studies of overnight oxygenation. Significant relationships (p less than 0.001) were obtained between mean oxygen saturation (SaO2) asleep and awake. There was similarly a significant relationship between lowest SaO2 asleep and awake, but this relationship was improved by the inclusion of awake arterial carbon dioxide tension (PaCO2). The patients who were more hypoxic at night than predicted from these regression relationships had similar survivals to the patients who were less hypoxic at night than predicted, whether excess nocturnal hypoxia was defined in terms of mean or lowest SaO2 during sleep. In the 66 patients who did not subsequently receive long-term oxygen therapy, none of the indices of nocturnal oxygenation was related to survival, the only significant predictor of survival being daytime arterial oxygen tension (PaO2). For all 97 patients, both mean nocturnal SaO2 and lowest SaO2 during sleep were related to survival (p less than 0.05), and percent predicted vital capacity was also related to survival (p less than 0.05). Neither of the oxygen saturations during sleep significantly added to the more readily and cheaply measured percent predicted vital capacity in determining survival in these patients. Thus, in patients with COPD, excess nocturnal hypoxemia is not associated with an impaired prognosis, and so studies of oxygenation during sleep cannot be recommended in the routine clinical management of these patients.

Female↗
PubMed1988

Should ipratropium bromide be added to beta-agonists in treatment of acute severe asthma?

In a double-blind randomized trial, 40 patients with acute severe asthma were given either nebulized salbutamol, 5 mg, or salbutamol, 5 mg mixed with ipratropium bromide 500 micrograms, on admission to hospital and again two hours later. There was no significant difference between the mean peak flows of the two treatment groups at any time. However, two hours after each treatment, there were fewer subjects in the ipratropium and salbutamol group whose peak flow rates had fallen back toward baseline levels than in the salbutamol only treatment group. Thus, although ipratropium did not improve the overall maximal bronchodilator response, it may have prolonged the duration of the response, which would be a clinically useful effect.

Acute Disease↗
PubMed1988

Prevalence of nocturnal hypoxaemia amongst men with mild to moderate hypertension.

Thirty men (aged 35-65) with untreated essential hypertension (BP greater than or equal to 140/90), confirmed by 24-h ambulatory monitoring, had overnight recordings of arterial oxygen saturation (SaO2) in their own homes. The overnight saturation records were compared with those from a group of 30 normotensive control subjects matched for age, height and weight. The groups did not exhibit significant differences in any of the following parameters of overnight oxygenation: median SaO2, lowest SaO2 or frequency of 3 or 4 per cent dips in SaO2. We conclude that essential hypertension is not associated with excessive arterial hypoxaemia such as might be due to a sleep apnoea syndrome.

Adult↗