[Prognostic factors in survival of patients with obstructive respiratory insufficiency treated by long-term oxygen therapy. Data from the ANTADIR registry]. / Facteurs pronostiques de la survie des insuffisants respiratoires obstructifs traités par oxygénothérapie à long terme. Données de l'observatoire de l'ANTADIR.

Prognostic survival factors in COPD patients obtaining long-term oxygen therapy (LTO) through 25 french associations were studied using data from the ANTADIR register. Selection criteria included age (50 to 79 yr), FEV1/VC < 60%, PaO2 < 60 mmHg and start of therapy between beginning 1984 and end 1988. A total of 1,775 patients were selected (1,462 men, 313 women, mean age 66.1 yr). PaO2 was 50.9 +/- 5.8 mmHg, PaCO2 47.1 +/- 5.8 mmHg, FEV1 8.81 +/- 0.31 l (30.4 +/- 11.1% of predicted values) and FEV1/VC 37.7 +/- 10.1%. Overall survival was 81.6% at 1 yr, 68.6% at 2 yrs, 55.7% at 3 yr, 44.9% at 4 yr and 37.3% at 5 yr (survival median 3.5 yr). Age was the most predictive survival factor (5 yr survival 48.8% for 50-59 yr-old patients vs 27.3% for 70-79). Survival was longer in women (49% at 5 yr vs 34.9% for men). After stratification by age, FEV1, FEV1/VC, PaO2, PaCO2 and Body Mass Index (BMI) were all significant predictive factors for men. FEV1/VC was the only prognostic factor for women. For all the population multivariate analysis showed that age, sex and BMI were the most significant variables. A prognostic score determined from the final Cox model and based on sex, age, BMI, FEV1, PaO2 will be validated in an independent patient series. Our data confirm the influence of age, airways obstruction and hypoxemia on survival of COPD patients under LTO. Furthermore they demonstrate a poorer survival in men, in underweight patients and in non hypercapnic patients.

Theophylline disposition in patients with COLD with and without hypoxemia.

This study aimed to assess the effect of hypoxemia on theophylline disposition. Ten patients with a mean (+/- SEM) of 58 +/- 3 years with COLD (PaO2 55 +/- 1 mm Hg, PaCO2 46 +/- 2 mm Hg, and pH of 7.39 +/- 0.01) were hospitalized to have oxygen therapy. Before starting O2, they received intravenously, 4 mg/kg of theophylline over a 20-minute period; blood samples and urine were collected for six hours. The results suggested that hypoxia does not influence the disposition of theophylline or its metabolites.

[Critical study of the indications for long-term oxygen therapy. Chronic obstructive bronchopneumopathies]. / Etude critique des indications de l'oxygénothérapie à long terme. Bronchopneumopathies chroniques obstructives.

Numerous studies have shown that longterm oxygen therapy in hypoxaemic patients with chronic airflow obstruction (BPCO) is capable of improving the prognosis and decreasing the risk of cardio-respiratory decompensation; in addition sometimes physical capacity and intellectual capacity is improved. Another result often noted is a reduction in the mean hospital stay which corresponds to an improvement in the quality of life. A PaO2 constantly below 55 mmHg (7.3 kPa) is defined by the majority of authors as a precarious state. At this level even a small change in alveolar ventilation or disturbance of distribution would lead to an important fall in the oxygen content of the arterial blood. The stability of the PaO2 during the weeks of respiratory reeducation with specially controlled medical treatment, as well as the willing consent of the patient and his family, are indispensable conditions for the prescription of OLT. When hypoxaemia is of moderate severity (PaO2 between 50 and 60 mmHg (6.6-8 kPa), prolonged medical treatment (with abstention from tobacco) for at least two months is advised and a study of complementary criteria to further validate the indications for oxygen. Such features would include a worsening of the hypoxaemia during exercise of 30 to 40 watts (PaO2 less than 50 mmHg, 6.6 kPa), an elevated haematocrit (greater than 55%), a rise of the P (A-a)O2 (greater than 30 mmHg or 4 kPa), a nocturnal desaturation even in the absence of apnoea (oxyhaemoglobin saturation (SaO2) of less than 80% for more than 50% of the time asleep). Added to these criteria are the radiological, echographic and clinical signs of the effect of hypoxaemia on the pulmonary circulation. Frank pulmonary arterial hypertension observed in hypoxaemia of moderate severity when the PaO2 is in the region of 55 mmHg and is an argument for the prescription of OLT. Amongst the developing criteria, exacerbations of respiratory encephalopathy, intellectual deterioration, progressive wasting, permanent ventilatory embarrassment with tachypnoea, should be borne in mind as the occasion arises. A schedule of 18 hours per day (without stopping for more than 3 hours) is necessary to obtain an improved survival and places a great demand on patient co-operation and on their environment. A prolonged educational programme is required. To achieve such a schedule the use of portable oxygen may be justified so that patients can lead a normal social life.(ABSTRACT TRUNCATED AT 400 WORDS)

Risk of lung cancer among iron ore miners: a proportional mortality study of 1,075 deceased miners in Lorraine, France.

A proportional mortality study of 1,075 iron ore miners in Lorraine, France, who died between 1960 and 1976 showed a significant excess of lung cancer mortality (proportionate mortality ratio = 2.25). Moreover, proportionate lung cancer mortality increased with the duration of work underground (proportionate mortality ratio = 4.24 for subjects who worked underground for more than 30 years) and was higher among pneumoconiotic (siderotic) miners (proportionate mortality ratio = 3.85) than among nonpneumoconiotic miners. These results were confirmed by a case-control study nested in the mortality study. Smoking habits could not be estimated retrospectively with sufficient accuracy to be taken into account. Although the proportion of smokers among contemporary iron ore miners is larger than in the French male population, occupational factors may also play a role; radiation exposure can be ruled out because there is no detectable radioactivity in the Lorraine mines, but dust exposure may be considered as an etiologic factor owing to the relationship between siderosis and lung cancer.

Two-dimensional echocardiographic assessment of the right ventricle in patients with chronic obstructive lung disease.

A consecutive series of 40 patients (39 men, one woman; mean age 54.1 +/- 8.2 years) with chronic obstructive lung disease (COLD) underwent right heart catheterization and 2-D echocardiographic examination within 72 hr. An adequate 2-D echocardiographic study was obtained in 32 patients (80 percent) using the apical and/or subcostal views. Mean pulmonary artery pressure at rest and during exercise were correlated with right ventricular diameters and areas in end-systole and end-diastole (r = 0.63 to 0.73). Correlations between right ventricular free wall thickness and pulmonary artery pressure were weak (r = 0.51 and 0.57). Right ventricular end-diastolic pressure was also weakly correlated with right ventricular dimensions (r = 0.45 to 0.51), whereas right ventricular area fractional shortening was not correlated with hemodynamic parameters. Patients with previous episode of right heart failure had larger right ventricles than those without such episodes. Thus, 2-D echocardiography appears useful to study the right heart chambers in patients with COLD.

[Evaluation of the performance of 2 mini-flow meters]. / Vérification des performances de deux débitmètres de pointe miniatures.

Two mini-peak flow meters, the Airmed (mini-Wright) and the Medicheck (Pulmonary Monitor), were assessed against a reference electronic spirometer (Spiromatic, based on a pneumotachograph, integrator and an Apple II computer) in a series of 10 healthy subjects and 20 patients with chronic obstructive lung disease. The devices to be tested were mounted in series with the reference instrument; each subject did five trials. It was found that the Airmed instrument overestimated the flows up to 9 l X s-1 (i.e. in patients, average difference 0.86 l X s-1, p less than 0.001; in healthy subjects, average difference 0.35 l X s-1, p less than 0.001). The correlation with the results of the reference instrument was high (r = 0.992) in healthy subjects, whose regression slope was less than unity (0.763). In patients the correlation was satisfactory (r = 0.974), and the slope close to 1 (1.05). The Medicheck overestimated slightly the results of patients (difference 0.17 l X s-1, p less than 0.01); in normal subjects the overestimation was present only below 10 l X s-1 and the difference with the reference instrument nonsignificant (average 0.19 l X s-1). The results were closely related to those of the reference spirometer in both healthy subjects (r = 0.960) and patients (r = 0.936). As for the first instrument the slope of the regression was below 1 in healthy subjects (0.751) and practically one (1.01) in patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of the mechanical impairment on the ventilatory response to CO2 in chronic airway obstruction.

The purpose of this study was to assess the relationship between the breathing pattern response to CO2 and the severity of mechanical impairment in twenty patients with COLD. The CO2 response was compared to that of a control group of twelve normal subjects. All patients had airway obstruction (FEV1 = 40 +/- 14% of predicted; means +/- SD) and hyperinflation (FRC = 154 +/- 23% of predicted). Tidal volume (VT), inspiratory and total cycle duration (TI, TT), occlusion pressure (P0.1) and endtidal PCO2 were measured at rest and during hyperoxic CO2 rebreathing. On the same day, in all patients, arterial blood gas analysis, spirometric and plethysmographic measurements were made. The slope (S) of the P0.1 response (SP 0.1) to increasing endtidal PCO2 was negatively correlated with airway resistance (r = -0.59; p less than 0.01). Although the flow response, S(VT/TI), was positively and closely correlated with SP 0.1 (r = 0.88; p less than 0.001), it also appeared to be independently influenced by obstruction (p less than 0.01). The tidal volume response, SVT, was principally correlated with inspiratory capacity (r = 0.90; p less than 0.001) and also, independently, with Vmax50 (p less than 0.01). SVT was diminished in seventeen patients, ten of whom only had a decreased S(VT/TI). The shortening in TI during hypercapnia was most marked in patients with the greatest S(P0.1), who did not have arterial hypercapnia at rest. These results suggest: that the poor VT response to CO2 in COLD patients is principally caused by a limitation in inspiratory volume expansion.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison between ventilatory and mouth occlusion pressure responses to hypoxia and hypercapnia in healthy sleeping man.

Ventilatory and mouth occlusion pressure (P0.1) responses to progressive isocapnic-hypoxia and hyperoxic-hypercapnia were compared in eleven healthy sleeping men during the same night. Hypoxic and hypercapnic responses were determined during wakefulness, non-rapid and rapid-eye-movement sleep. The following parameters were measured: minute ventilation (VE), tidal volume (VT), 'duty cycle' (TI/TT), mean inspiratory flow rate (VT/TI) and P0.1, an index of the neuromuscular inspiratory drive. To allow a direct comparison between the two types of chemostimuli, responses were characterized by the value of the different parameters at 'equivalent' levels of hypoxia and hypercapnia, i.e., at levels which produced the same P0.1 during wakefulness: an oxyhaemoglobin saturation (Sao2) of 94% during the isocapnic-hypoxic tests (PETCO2 = 42.5 +/- 1.2 mmHg) was found to be equivalent to a PETCO2 of 47.4 +/- 3.7 mmHg during hypoxic-hypercapnic tests. For both tests, the arousal levels of the stimulus and of P0.1 were similar in all sleep stages. Sleep did not significantly modify P0.1 or breathing pattern responses to hypoxia (Sao2 = 94%). In contrast, at the 'equivalent' level of hypercapnic stimulation, P0.1 (P less than 0.05) and VE (P less than 0.01) responses were significantly impaired, particularly in REM sleep, with a decrease in VT (P less than 0.01) and VT/TI (P less than 0.05) responses. The results suggest that CO2 intracranial receptor mechanisms are more affected by sleep than the O2 peripheral receptor activity.

Maximal oxygen consumption and pulmonary circulation in patients with chronic bronchitis.

In order to study the relations between maximal oxygen consumption during exercise (VO2max) and the pulmonary circulation when pulmonary artery pressure (PPA) and pulmonary vascular resistance (PVR) are normal or close to normal, we evaluated twenty-three patients with chronic bronchitis, in stable clinical condition. All these patients performed a progressive exercise test on a bicycle ergometer until exhaustion (VO2max); they were also subjected to right heart catheterization at rest and during light exercise at constant load. In these patients with moderate functional impairment, we observed on average a significant, although weak, correlation (r = -0.52, P less than 0.01) between pulmonary vascular resistance at rest and VO2max. When VO2max exceeded 2 1 min-1, PVR was below 210 dyn s cm-5. From the heart rate during maximal exercise we computed the oxygen pulse (O2Pmax). In eight patients O2Pmax was reduced (less than or equal to 11 ml) with maximal heart rate close to its predicted value; in seven of these subjects PVR was abnormal and Ppa at rest was at least 20 mmHg. Thus it seems that in chronic obstructive bronchitis mild disturbances in pulmonary circulation may be a contributory factor in the limitation of exercise performance, and a maximal exercise test may help to detect pulmonary hypertension in these patients.

[Shoshin beriberi with hyponatremia in a beer drinker]. / Shoshin béribéri avec hyponatrémie chez un buveur de bière.

Shoshin beriberi - a fulminant form of cardiovascular beriberi - and severe hyponatraemia were observed concomitantly in a heavy beer drinker. Hyponatraemia due to water overload and not to sodium deficiency is not a feature of the true beer drinker syndrome. Cardiogenic shock with major lactic acidosis developed. This case confirms the remarkable effectiveness of thiamine and the ineffectiveness of cardiotonic and vasoconstrictive drugs in such cases.

[Respiratory encephalopathy]. / Encéphalopathie respiratoire.

Encephalopathy is a common and sometimes a presenting feature of decompensated chronic respiratory failure. There is a wide number of clinical and paraclinical signs of this condition and four grades of severity without a close correlation with blood gas changes. This condition is the consequence of complex metabolic and circulatory disturbances resulting from the blood gas abnormalities. The prognosis is good when the respiratory failure is quickly and correctly treated.

[Effect of artificial ventilation with an end-expiratory plateau on gas exchange amd hemodynamics in chronic respiratory failure]. / Effet de la ventilation artificielle avec un plateau télé-inspiratoire sur les échanges gazeux et l'hémodynamique chez les insuffisants respiratoires chroniques.

Previous studies of pulmonary models and with animals have shown that in obstructive disease of the airways, ventilation with an end-expiratory plateau improves ventilation distribution. Paradoxically, there has been no data published on patients with obstructive disease. For this reason, we examined the effects of mechanical ventilation with an end-expiratory plateau on gas exchange and haemodynamics in 12 patients presenting acute exacerbations of chronic respiratory failure. Following a period of conventional controlled ventilation, two plateaux of 0.3 and 0.5 s respectively are successively introduced while the I/E ratio (1/2.5) and then inspiratory flow (respiratory frequency and end-tidal volume remaining the same) are kept constant. PaCO2 decreases by approximately 10% with the addition of each plateau. In spite of a moderate increase in mean airway pressure (+8%), greatest improvement in gas exchange is observed with the longer plateau (0.5 s), maintaining expiration time (I/E constant) : a decrease in PaCO2 and in VD/VT (approximately - 14%), an increase in PaO2 (+7%) and a decrease of venous admixture (shunt + shunt effect : - 18.5%). The plateau tends to reduce ventilation/perfusion mismatch, whereas maintaining prolonged expiration assures "emptying" of slow alveoli. However, no matter which plateau is used, cardiac output decreases by more than 10% in six patients, probably due to a drop in systemic venous return. PaCO2 increase is too slight to hinder a decrease in arterial oxygen transport. The variability of these results accounts for patient diversity and restricts the indication of end-expiratory plateau to patients with severe ventilatory distribution disturbances who can benefit from close cardiorespiratory monitoring.