ABSTRACT
Long-term domiciliary oxygen therapy in patients with chronic respiratory failure significantly improves both survival and quality of life. These therapeutic objetives are only achieved by daily oxygen therapy of more than 15 hours. For a period of 3 months, we have prospectively measured the duration of oxygen therapy in 930 patients with chronic airflow obstruction. This is carried out by reading the meters on the oxygen concentrators, or for liquid oxygen by checking the weight of the cylinders at each delivery, making allowances for the flow rate and also for natural loss from evaporation. The instructions for oxygen therapy and the true therapy of the patient were then gathered using a questionnaire. The practitioners were questioned on the prescription for oxygen therapy which had been made for each patient, and more generally on their usual criteria for prescribing long-term oxygen therapy. The patients (82% male) were aged between 67 +/- 8 years, and were on domiciliary oxygen therapy 36 +/- 24 months, with hypoxaemia (PaO2 = 56 +/- 9 mmHg), hypercapnea (PaCO = 47 +/- 8 mmHG) and suffering from airflow obstruction (FEV1/VC = 42 +/- 14%). The duration of prescribed oxygen therapy was on average 16 +/- 3 hours. The mean duration of oxygen therapy achieved was 14.5 +/- 5 hours, but only 45% of the patients (419/930) managed daily oxygen therapy superior of equal to 15 hours and were categorised as compliant.(ABSTRACT TRUNCATED AT 250 WORDS)
Subject(s)
Home Care Services , Long-Term Care , Oxygen Inhalation Therapy , Patient Compliance , Adult , Aged , Aged, 80 and over , Female , Forecasting , Humans , Hypercapnia/physiopathology , Hypoxia/physiopathology , Life Style , Lung Diseases, Obstructive/physiopathology , Lung Diseases, Obstructive/therapy , Male , Middle Aged , Oxygen Inhalation Therapy/instrumentation , Oxygen Inhalation Therapy/methods , Prescriptions , Prospective Studies , Respiratory Insufficiency/physiopathology , Respiratory Insufficiency/therapy , Smoking/physiopathology , Time FactorsABSTRACT
During the course of chronic airflow obstruction the effect of the pathological process and compensatory mechanisms that take place in the lungs to limit these effects express themselves by easily indentifiable clinical signs. The limitations of expiratory flow is responsible for the prolongation of the duration of maximal expiration: Pursed lipped breathing is probably the method used by certain patients to limit airway collapse; the increase in the residual volume and functional residual capacity results in distortion of the thorax and a change in the configuration of the inspiratory muscles, reducing their capacity to generate pressures (Hoover's sign: respiratory pulse, hypertrophy of the accessory respiratory muscles, thoraco-abdominal asynchrony); the considerable increase in the inspiratory thoracic depression accounts for the inspiratory descent of the trachea and the sub-sternal "tug". Finally the ventilatory pattern is different, ventilation being rapid and superficial, probably in order to adapt to the constraints imposed by the pathological process.
Subject(s)
Lung Diseases, Obstructive/diagnosis , Abdominal Muscles/physiopathology , Biomechanical Phenomena , Diaphragm/physiopathology , Humans , Lung Diseases, Obstructive/physiopathology , Maximal Voluntary Ventilation , Respiration , Respiratory System/physiopathology , Thorax/physiopathology , Trachea/physiopathologyABSTRACT
The natural history and pathophysiology of chronic airflow obstruction (BPCO) remain poorly understood. Therapy cannot cure the disease but should be aimed at palliating its effects: to reduce dyspnoea, to improve the exercise performance, to minimise the complications, to stabilise the disease and improve the quality of life, to prevent by combatting those factors which favour the development of the disease e.g. pollutants, tobacco, infections etc. The pre-requisite of any therapeutic action should be to recognise those factors which contribute to the pathology and the compensatory phenomena with which the organ opposes them. According to whether the compensation is insufficient or inappropriate the therapy should be either increased or designed to combat it. The therapeutic perspective demands a better understanding of the relationship between the respiratory centre and effector muscles on the one hand and the relationship between ventilation and pulmonary perfusion on the other.
Subject(s)
Lung Diseases, Obstructive , Bronchi/metabolism , Diaphragm/physiopathology , Humans , Inspiratory Capacity , Lung Compliance , Lung Diseases, Obstructive/physiopathology , Lung Diseases, Obstructive/therapy , Respiratory Center/physiopathology , Ventilation-Perfusion RatioABSTRACT
Bronchography enables an appreciation of the morphology and dynamics of the bronchi inaccessible to the fibroscope. However, this examination may aggravate pulmonary function in patients with chronic airflow obstruction. We have studied the effects of bronchography on forced expiration in order to identify and quantify possible spirometric changes. Thus spirometric tests were done at different times during the examination (V.C., F.E.V., flow-volume curves): before and after anaesthetizing the upper airways with xylocaine, after the introduction of contrast to the bronchi and finally after a Salbutamol aerosol. Spirometric values were unaffected by anaesthesia of the upper airways. On the other hand, the introduction of contrast led to a clear and constant fall in maximum expiratory flow, associated with a fall in forced vital capacity. These changes could not be reversed either after inhalation of Salbutamol or sub-cutaneous Terbutaline. The mechanisms producing the spirometric changes which we report does not seem to involve either the adrenergic system or the irritant receptors. Bronchial obstruction produced by the contrast does not alone appear to explain the changes induced by bronchography. Other mechanisms, not yet identified, probably contribute to the decrease in maximum expiratory flow.
