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Biomedical subjects

M A Branthwaite

Publications and source records attributed to M A Branthwaite.

At least 19 recordsLinked to original sources
PubMed1992

Domiciliary nocturnal nasal intermittent positive pressure ventilation in hypercapnic respiratory failure due to chronic obstructive lung disease: effects on sleep and quality of life.

BACKGROUND: Domiciliary assisted ventilation, using negative or positive pressure devices, is an effective treatment for respiratory failure due to chest wall deformity and neuromuscular disease. Negative pressure ventilators have been used with some success in patients with chronic obstructive lung disease in hospital, but attempts to continue treatment at home have been disappointing. This study evaluates the practicalities of nasal intermittent positive pressure ventilation at home in patients with chronic obstructive lung disease and the effect on sleep and quality of life. METHODS AND RESULTS: Twelve patients with chronic obstructive lung disease and hypercapnic respiratory failure received nasal intermittent positive pressure ventilation at home during sleep. At six months eight were continuing with the ventilation. One patient had died and three had withdrawn because they were unable to sleep with the equipment. Full polysomnography performed during ventilation in patients continuing treatment at six months showed an increase in mean PaO2 of 11% (+2% to +23%) and lower mean transcutaneous carbon dioxide tensions (by -2.7 (-1.3 to -5.1) kPa) overnight compared with spontaneous breathing before the start of nasal intermittent positive pressure ventilation. Total sleep time and sleep efficiency changed during ventilation by +72.5 (+21 to +204) minutes and +5% (-3% to +30%) respectively; sleep architecture and the number of arousals were unchanged. Quality of life did not change but was no worse during ventilation. At one year seven patients were still using the ventilator and PaCO2 and bicarbonate ion concentration during the day had improved further by comparison with the values at six months (change from baseline -1.7 (-2.1 to -0.6) kPa, p less than 0.05, and -6.3 (-11.9 to -4) mmol/l, p less than 0.05). CONCLUSIONS: Nasal intermittent positive pressure ventilation can be used effectively at home during sleep in selected patients with chronic obstructive lung disease. Its future place in management can be established only by formal comparison with long term oxygen therapy.

Female↗
PubMed1991

Domiciliary nocturnal nasal intermittent positive pressure ventilation in COPD: mechanisms underlying changes in arterial blood gas tensions.

The improvement in arterial blood gas tensions following assisted ventilation in chronic obstructive pulmonary disease (COPD) has usually been attributed to the relief of incipient or established respiratory muscle fatigue. The contribution of changes in the load placed upon and the drive to the respiratory muscle pump have not been evaluated. We have investigated the contribution of changes in respiratory muscle strength, the ventilatory response to CO2 and ventilatory function to changes in arterial blood gas tensions in eight patients with severe COPD completing six months domiciliary nasal intermittent positive pressure ventilation. Six patients showed a reduction and two an increase in arterial carbon dioxide tension (PaCO2), median (range) for eight patients, -0.9 kPa (-1.5 to +0.4) (p less than 0.05) and seven showed an improvement in arterial oxygen tension (PaO2), +0.7 kPa (-0.4 to +1.7) (p less than 0.05) during daytime spontaneous breathing. The reduction in PaCO2 was not related to increased inspiratory muscle strength but was correlated with a decrease in gas trapping (Spearman rank correlation coefficient (r(S)) 0.85, p less than 0.05) and in the residual volume (r(s) 0.78, p less than 0.05), suggesting reduced small airway obstruction and, therefore, a reduction in load. The change in PaCO2 also correlated with the increase in ventilation at an end-tidal CO2 of 8 kPa during rebreathing (r(s) -0.76, p less than 0.05) suggesting improved chemosensitivity to CO2. Our data do not support the hypothesis that improvements were due to the relief of muscle fatigue. We suggest that the contribution of changes in load and central drive warrant further investigation.

Female↗
PubMed1990

Non-invasive mechanical ventilation for acute respiratory failure.

The value of mechanical ventilation using intermittent positive pressure ventilation delivered non-invasively by nasal mask was assessed in six patients with life threatening exacerbations of chronic respiratory disease. Median (range) arterial oxygen and carbon dioxide tensions were 4.4 (3.5-7.2) kPa and 8.7 (5.5-10.9) kPa respectively, with four patients breathing air and two controlled concentrations of oxygen. The arterial oxygen tension increased with mechanical ventilation to a median (range) of 8.7 (8.0-12.6) kPa and the carbon dioxide tension fell to 8.2 (6.5-9.2) kPa. Four patients discharged after a median of 10 (8-17) days in hospital were well five to 22 months later. One died at four days of worsening sputum retention and another after five weeks using the ventilator for 12-16 hours each day while awaiting heart-lung transplantation. This technique of mechanical ventilation avoids endotracheal intubation and can be used intermittently. Hypercapnic respiratory failure can be relieved in patients with either restrictive or obstructive lung disease in whom controlled oxygen treatment results in unacceptable hypercapnia. Respiratory assistance can be tailored to individual need and undertaken without conventional intensive care facilities.

Acute Disease↗
PubMed1990

Role of nocturnal hypoxaemia in the genesis of systemic hypertension.

Two groups of patients with nocturnal arterial oxygen desaturation were compared. The degree of nocturnal oxygen desaturation, as reflected by the percentage of total sleep time spent with an oxygen saturation less than 90 and 80%, was similar in patients with the obstructive sleep apnoea syndrome (OSAS) and in those with nocturnal hypoventilation (NH) secondary to restrictive chest wall disease. Systemic hypertension was present in 16 of the 24 OSAS patients but in only 6 of the 24 with NH (p less than 0.005). Multiple regression analysis demonstrated that this difference remained significant even after adjustment for age, sex, weight and history of smoking. It is likely that factors other than nocturnal hypoxaemia are important in the aetiology of systemic hypertension in patients with sleep-related breathing disorders.

Female↗
PubMed1990

The use of protriptyline for respiratory failure in patients with chronic airflow limitation.

Treatment of nocturnal hypoventilation in patients with restrictive chest wall disease and respiratory failure, results in improved daytime arterial blood gas tensions, increase in functional ability and longer survival. Success has been achieved with the use of protriptyline which reduces the duration of rapid eye movement (REM) sleep during which nocturnal hypoventilation occurs. Eighteen patients with severe chronic airflow limitation (CAL), took part in a randomized, double-blind, crossover trial of protriptyline and placebo. Seventeen patients completed the study. The use of protriptyline was associated with a fall in the median percentage of total sleep time spent in REM from 16 to 8.8% (p less than 0.01). This was associated with a reduction in the median daytime arterial carbon dioxide tension from 6.4 kPa (range 5.2-8.5 kPa) to 5.8 kPa (range 5.0-8.1 kPa) (p less than 0.01); increased respiratory muscle strength (p less than 0.05), and increased six minute walking distance from a median of 258 m (range 58.5-585 m) to 275 m (range 171-598 m) (p less than 0.02). We found pharmacological treatment of REM-related nocturnal hypoventilation in patients with CAL to be effective, but anticholinergic side-effects, particularly in older male patients, might preclude long-term treatment.

Adult↗
PubMed1979

Cardiac pacemaker insertion: a study of the anaesthetic and postoperative complications.

One hundred and three patients undergoing pacing procedures have been studied, the majority requiring the insertion of an epicardial system under general anaesthesia. The main findings were of an elderly group of patients with a high incidence of associated disease, who suffered predominantly from pulmonary and renal complications. Methods of reducing these complications, particularly in relation to general anaesthesia are discussed.

Adolescent↗
PubMed1979

IPPB and hypercapnia in respiratory failure: the effect of different concentrations of inspired oxygen on arterial blood gas tensions.

Fourteen patients with acute exacerbations of chronic bronchitis and hypercapnia received two treatment periods with Intermittent Positive Pressure Breathing, the ventilator being driven by gas containing about 24% or about 45% oxygen. Arterial PO2 and PCO2 were measured before, during and after each treatment. The results demonstrated that increasing hypercapnia did not, as a rule, occur when 45% oxygen was used as the driving gas. When hypercapnia did occur it appeared to be independent of the inspired oxygen concentration. The importance of short treatment periods, correct ventilator settings and supervision of the patient during and after treatment is emphasised.

Carbon Dioxide↗
PubMed1978

Lysosomal enzyme release from the lungs after cardiopulmonary bypass.

The activity of some lysosomal enzymes has been investigated in venous and arterial blood collected from patients undergoing cardiopulmonary bypass. Before bypass, there is no arterio-venous difference in the activity of n-acetyl-beta glucosaminidase, beta-glucuronidase or lysozyme. After operation, the activity of n-acetyl-beta-glucosaminidase is greater in arterial than in superior caval blood within the first 24 h after bypass, and a small arterio-venous increment in the activity of beta-glucuronidase can also be detected towards the end of the first day. The site of enzyme release has not been identified with certainty but may lie within the pulmonary circulation.

Acetylglucosaminidase↗
PubMed1977

Asthma: analysis of sudden deaths and ventilatory arrests in hospital.

The incidence of episodes of unexpected ventilatory arrest, some of which led to sudden death, was studied in 1169 consecutive hospital admissions for asthma. Of the most acute cases, 458 were initially managed in a special care unit where only one ventilatory arrest occurred. A further nine cases of arrest, three of which proved fatal, happened on general wards. Accepted clinical criteria of a severe attack were not present in those episodes occurring outside the unit, which were apparently mild attacks. The risk of sudden death could not be related to the severity of the attack but it did correlate with the presence of excessive diurnal variation in peak expiratory flow rate (PEFR). Special treatment of patients with this sign might reduce mortality.

Asthma↗
PubMed1977

Lysosomal enzyme release during cardiopulmonary bypass.

Lysosomal enzyme release occurs during cardiopulmonary bypass in man but the tissues from which these enzymes originate have not been identified. The activity of N-acetyl beta-glucosaminidase in plasma increases to a degree which is proportional to the duration of bypass and this enzyme may therefore be a better marker than beta-glucuronidase of tissue damage caused by cardiopulmonary bypass, as distinct from tissue damage solely to the operative procedure.

Acetylglucosaminidase↗
PubMed1977

Significance of changes in cerebral electrical activity at onset of cardiopulmonary bypass.

A study of 100 patients requiring open-heart surgery has been undertaken to ascertain whether prophylactic measures designed to minimise cerebral damage have influenced the incidence or severity of changes in cerebral electrical activity recorded at the onset of cardiopulmonary bypass. The incidence of change in cerebral electrical activity remains high but the severity of the disturbances has diminished as compared with a series investigated before prophylactic measures were introduced. Changes suggestive of cerebral depression were particularly notable in children under 10 years of age. The significance of these findings is discussed in the context of factors which might influence cerebral electrical activity at the onset of bypass.

Age Factors↗