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Biomedical subjects

H R Gribbin

Publications and source records attributed to H R Gribbin.

17 recordsLinked to original sources
PubMed1987

Diaphragm paralysis causing ventilatory failure in an adult with the rigid spine syndrome.

A syndrome consisting of a rigid spine and myopathy predominantly affecting proximal limb muscles has been previously described in children, and as with most neuromuscular disorders, the respiratory muscles appear to be affected only at an advanced stage in the disease. We describe an adult male with this syndrome who presented with ventilatory failure caused by severe respiratory muscle weakness and who demonstrated profound nocturnal arterial oxygen desaturation, particularly during rapid eye movement sleep. Treatment with negative pressure ventilation initially resulted in only modest improvements in symptoms, blood gas tensions, and nocturnal desaturation. The cause of this only partial improvement was upper airway obstruction provoked by the mode of ventilatory support used. After tracheostomy there was a dramatic and sustained improvement in symptoms and blood gas tensions and complete abolition of nocturnal arterial oxygen desaturation. This is the first report of an adult with the rigid spine syndrome presenting with ventilatory failure and cor pulmonale due to severe respiratory muscle weakness.

Adult↗
PubMed1981

Assessment of bronchial beta blockade after oral bevantolol.

We have applied a new method for quantitative measurement of bronchial beta adrenoceptor blockade to a new beta adrenoceptor antagonist, bevantolol. Dose-response curves to a beta agonist, albuterol, were obtained in six normal subjects by measuring specific airway conductance (sGaw) after increasing doses of inhaled albuterol. These were repeated on three separate occasions 2 hr after subjects had taken oral placebo or bevantolol (75 or 150 mg), double-blind in random order. The dose-response curves after bevantolol 75 mg were displaced in the right of placebo in four subjects and after 150 mg were displaced to the right of placebo in all subjects. The mean dose ratios for bevantolol 75 or 150 mg were 1.02 and 2.77, much the same as those obtained in the same subjects after practolol 100 and 200 mg and considerably less than that after propranolol 40 mg. The mean reductions in exercise heart rate were 25% and 29% after bevantolol 75 and 150 mg. Our data show that bronchial beta blockade after a beta blocking drug can be assessed quantitatively in many by a double-blind technique.

Adrenergic beta-Antagonists↗
PubMed1981

Bronchial and cardiac beta-adrenoceptor blockade--a comparison of atenolol, acebutolol and labetalol.

Bronchial and cardiac beta-adrenoceptor blockade have been compared in six normal subjects after three beta-adrenoceptor antagonists. Single and double doses of atenolol (50 and 100 mg), acebutolol (100 and 200 mg) and labetalolol (150 and 300 mg) were studied on separate occasions. 2 Salbutamol airway dose-response curves were obtained by measuring the airway response as the change in specific airway conductance (sGaw) after increasing doses of inhaled salbutamol. Bronchial beta-adrenoceptor blockade was assessed after each drug as the dose of salbutamol needed to cause a 50% increase in sGaw (sGaw D50). 3 Cardiac beta-adrenoceptor blockade was assessed after the same doses of each beta-adrenoceptor antagonist, by measuring the percentage reduction in exercise heart rate from control, after exercise for 5 min at 70% of the subject's maximum work rate. 4 Atenolol 50 and 100 mg caused least bronchial beta-adrenoceptor blockade and the greatest reduction in exercise heart rate. 5 Acebutolol 100 and 200 mg and labetalol 150 and 300 mg produced more bronchial beta-adrenoceptor blockade than atenolol. 6 With this approach new beta-adrenoceptor antagonists can be assessed without putting asthmatic patients at risk.

Acebutolol↗
PubMed1981

Sustained release oral aminophylline in patients with airflow obstruction.

Twenty-four patients with reversible airflow obstruction under suboptimal control on conventional therapy entered a double-blind placebo-controlled trial of additional oral sustained release aminophylline. Assessment was by diary cards, twice daily PEFR, and weekly FEV1. Nineteen patients completed the trial satisfactorily. Eleven were improved subjectively by addition of aminophylline. The mean PEFR for all 19 patients rose from 232 1 min-1 SEM +/- 5, to 247 1 min-1 SEM +/- 4 (p less than 0.0001); nine individuals showed a statistically significant improvement in mean PEFR and 10 showed an improvement of greater than 200 ml in their FEV1. Improvement in PEFR on aminophylline was not at the expense of benefit from inhaled salbutamol. Unwanted effects of nausea, headache, and abdominal discomfort were recorded by 12 of the 24 patients entering the trial. Seventeen of the 19 patients completing the trial had plasma theophylline levels in the accepted therapeutic range of 10-20 mg 1(-1). The drug doses required to achieve these levels varied from 8.6-30.8 mg kg-1 24 hr-1 in the patients with no clinical or biochemical evidence of liver disease. Oral aminophylline can improve control of airflow obstruction in patients with moderately severe disease who are already receiving multiple medication, but side-effects often limit its use. The wide dose range required to achieve therapeutic plasma levels indicates that measurements of plasma theophylline are necessary for adequate interpretation of trials of theophylline compounds.

Adult↗
PubMed1981

Partial flow-volume curves to measure bronchodilator dos-response curves in normal humans.

We examined the use of partial expiratory flow-volume (PEFV) curves to obtain dose-response curves to an inhaled beta 2-adrenoceptor agonist (salbutamol) in eight normal subjects. Maximum expiratory flow at low lung volumes increased on both PEFV and full expiratory flow-volume curves, but the increase was always considerably greater on PEFV (28.4%) than on full (14.5%) curves. The percent increase in flow on the PEFV curve was not significantly influenced by the preceding volume history being 90-120 s of tidal breathing, forced expiration to residual volume, or breath holding after a full inflation. These results suggest that normal tone during tidal breathing is temporarily reduced but not abolished by a full inflation, and once basal tone has been restored it is not enhanced by a full expiration. In seven of the eight subjects a satisfactory cumulative dose-response curve to inhaled salbutamol was obtained with a plateau value of maximum flow at a dose of 110 microgram. The relatively good reproducibility of PEFV curves and the considerable bronchodilator signal obtained (29-70% increase in flow above base line in different individuals) suggest that such dose-response curves may be useful in studying normal bronchial pharmacology in vivo.

Adult↗
PubMed1981

Effect of beta-adrenergic blockade on respiratory and metabolic responses to exercise.

The responses to oral propranolol (80 mg) and placebo were compared in normal subjects during three studies on a cycle ergometer (progressive exercise and two 5-min constant work rate studies at 50 and 70% maximum). Heart rate (HR), ventilation (VE), CO2 output (VCO2) and O2 uptake (VO2) were measured in each study and metabolites in venous blood in the 70% study. Propranolol reduced HR in all studies and endurance time during progressive exercise. During constant-work-rate exercise the changes with propranolol depended on time and work rate. At 50% max, VO2, VCO2, and VE were reduced in early exercise but were similar by min 5. At 70% max, VO2 and VCO2 were again lower initially with propranolol but then rose more rapidly. By min 5 VE was greater with propranolol, coinciding with a rapidly rising venous lactate. We interpret the initial reduction in VO2 and VCO2 to reduced cardiac output and muscle perfusion with propranolol. The resulting increase in anaerobic metabolism during heavy exercise would explain the increased VE at min 5. The metabolic data are compatible with glycogen being the predominant muscle fuel.

Adult↗
PubMed1979

Quantitative assessment of bronchial beta-adrenoceptor blockade in man.

1. We describe a method for assessing bronchial beta-adrenoceptor blockade quantitatively in man. Specific airway conductance is measured after increasing doses of inhaled salbutamol and the extent to which the dose-response curve is displaced to the right after beta-adrenoceptor blocking drugs is used to assess bronchial beta-adrenoceptor blockade. 2. Salbutamol dose-response curves were plotted for six normal subjects by measuring sGaw 15 min after increasing doses of inhaled salbutamol. Salbutamol produced a 30-70% increase in sGaw. 3. Salbutamol dose response curves were obtained 2 h after oral practolol (100 mg and 200 mg) and oral propranolol (40 mg and 80 mg) on separate days and were displaced to the right. 4. The mean dose ratios for practolol 100 mg and 200 mg were 1.2 and 2.1 and for propranolol 40 mg and 80 mg they were 21 and 61 respectively.

Adrenergic beta-Antagonists↗
PubMed1979

A double-blind trial of oral aminophylline (Phyllocontin Continus tablets) in airflow obstruction: preliminary communication.

Twenty-two patients with reversible airflow obstruction were entered into a double-blind crossover trial of Phyllocontin Continus tablets and placebo to assess the additional benefit of the controlled-release aminophylline preparation when added to the patients' medication. Most patients were taking inhaled or oral steroids in addition to inhaled beta-sympathomimetics throughout the trial. The dosage of Phyllocontin tablets was adjusted in a pre-trial study to provide serum theophylline levels in the accepted therapeutic range of 10--20 mg/l. In the seventeen patients who completed the 8-week study a small, but significant, increase in both the patients' own recordings of PEFR and weekly clinic measurements of FEV1 was seen whilst on the active drug. Ten patients had improvement in FEV1 greater than 200 ml. Eleven patients recorded subjective improvement on the active drug and five out of ten patients who used inhaled beta-sympathomimetics p.r.n. showed a reduction in their usage of greater than 10%. Side-effects were reported by twelve patients.

Adult↗
PubMed1976

Reduced respiratory responses to carbon dioxide after propranolol: a central action.

In a double-blind study in six subjects propranolol significantly reduced the respiratory sensitivity to carbon dioxide rebreathing. This effect seems to have been due to beta-adrenergic blockade, since it was not seen with D-propranolol. In two subjects increasing doses of propranolol caused progressive reductions in respiratory sensitivity to values below normal and similar to those of patients with ventilatory failure. These changes are probably due to a central action of propranolol.

Adult↗
PubMedDate not supplied

Using body surface movements to study breathing.

The chest wall comprising both rib cage and abdomen moves during breathing, and when suitably calibrated this motion can be used to monitor pulmonary ventilation without the need for face-masks or mouthpieces. Such non-invasive methods of studying breathing are likely to become more widely used in the future, especially in the investigation of respiratory control and sleep-disordered breathing. This review describes the physiological basis of these measurements and examines the practical and theoretical limitations of calibration techniques based on the two degrees-of-freedom model of chest-wall motion.

Abdominal Muscles↗
PubMedDate not supplied

Management of respiratory failure.

Hypoxaemia and hypercapnia are common clinical problems. A clear understanding of the diseases and pathophysiological processes that cause respiratory failure is important in making decisions about the concentration of oxygen to give, the type of face-mask to use, and the place of artificial ventilation.

Humans↗