Influence of patient posture on oxygen saturation during fibre-optic bronchoscopy.

This study was designed to investigate the effect of posture on oxygen saturation during fibre-optic bronchoscopy (FOB). Thirty-eight consecutive patients requiring diagnostic FOB were randomized into two groups according to the initial posture in which the FOB was performed. In group 1 (20 patients), FOB was commenced supine, and in group 2 (18 patients) in a semi-recumbent position (45 degrees from horizontal). Sedation with midazolam was titrated according to clinical response. All patients received atropine 0.6 mg intravenously and topical lignocaine. Observations of peak, trough and plateau oxygen saturation and pulse rate were recorded during six study periods, each lasting 3 min. Periods 1 and 2 were pre- and post-sedation without supplemental oxygen, respectively. The bronchoscope was then inserted into the distal end of the trachea and observations taken during periods 3 and 4 (no supplemental oxygen) and periods 5 and 6 (2 l oxygen by nasal cannulae). In group 1, posture was changed from supine to semi-recumbent from periods 3-4 and reversed in periods 5 and 6. In group 2, posture changes were in reverse sequence. Patients with initial oxygen saturation of less than 90% or showing a fall below 85% during FOB were excluded. Five patients from each group were withdrawn because of hypoxia. In both groups, oxygen saturation fell significantly (P<0.001) following sedation. There was no significant change in saturation (peak, trough or plateau) with change in posture from supine to semi-recumbency (group 1) or the reverse (group 2). These correspond to periods 3-4 and 5 6 in both groups. Supplemental oxygen was associated with a significant rise in oxygen saturation in both postures, attaining levels close to presedation levels.

Occupational asthma due to methyl methacrylate and cyanoacrylates.

Five patients had asthma provoked by cyanoacrylates and one by methyl methacrylate, possibly because of the development of a specific hypersensitivity response. Acrylates have wide domestic as well as industrial uses, and inhalation of vapour emitted during their use can cause asthma.

Failure of once daily inhaled corticosteroid treatment to control chronic asthma.

Twelve patients with chronic asthma received either high dose beclomethasone once a day or standard doses of beclomethasone three times a day in a double blind crossover trial to determine whether inhalation once a day would be sufficient. With the once a day regimen peak expiratory flow rates fell significantly, symptoms of nocturnal asthma increased, and two patients withdrew from the study because of worsening asthma. Whether control can be achieved with steroids inhaled once a day by simply increasing the total daily dose remains to be seen.

Home nebulizers in severe chronic asthma.

Twenty-four outpatients who continued to have severe chronic asthma despite attending a chest clinic were studied. All were already using inhaled beta-agonists from a pressurized aerosol and regular inhaled corticosteroids. Nineteen were on long-term oral corticosteroids. Comparison was made between their symptoms and peak expiratory flow rate (PEFR) during 4 weeks on their usual treatment and the following month when they were also given 5 mg terbutaline night and morning by nebulizer. During the second month the symptom score for nocturnal asthma improved by 30% (P less than 0.01), for daytime wheeze by 23% (P less than 0.025) and shortness of breath by 15% (P less than 0.01). The prebronchodilator morning and evening PEFR increased by 8% (P less than 0.025) and 10% (P less than 0.01) respectively. A dose-response study with inhaled terbutaline in six patients before and after 4 weeks of nebulizer treatment showed no evidence of a decline in response. Home nebulizers produced considerable overall improvement. Because of variations in individual responses a monitored trial of the type which we have used is desirable before a decision is made on long-term treatment.

Synergism between platelet-activating factor (PAF-acether) and prostaglandin E2 in man.

In animal experiments the oedema in the acute inflammatory response is dependent on both increased blood flow and increased vasopermeability (the two component hypothesis). We have confirmed the validity of this hypothesis in man by demonstrating synergistic interaction between PAF-acether (a permeability agent) and prostaglandin E2 (a vasodilator). The mixture of PAF-acether and PGE2 (50 ng; 0.5 micrograms) produced a larger cutaneous wheal volume response than could be accounted for either by summation of the responses to the individual mediators or by the slopes of their dose response curves.