Biomedical subjects

J Moinard

Publications and source records attributed to J Moinard.

6 recordsLinked to original sources

PubMed1994

Effect of inhaled nitric oxide on hemodynamics and VA/Q inequalities in patients with chronic obstructive pulmonary disease.

Nitric oxide (NO) has been reported to be an endothelium-derived relaxing factor, and hypoxic pulmonary vasoconstriction seems to be enhanced by inhibitors of endothelially dependent vascular relaxation. We examined the circulatory effects of inhalation of 15 ppm NO in air in 14 hypoxic patients suffering from chronic obstructive pulmonary disease (COPD). Of these patients 4 breathed 100% O2 before NO. The effects of NO inhalation on pulmonary gas exchange were also studied in 12 of these patients using the multiple inert gas elimination technique, 3 of whom breathed air, 100% O2, and 15 ppm NO in air in succession. Under baseline conditions, both mean +/- SD pulmonary artery pressure and pulmonary vascular resistance were increased (Ppa = 24.3 +/- 10.4 mm Hg and PVR = 3.3 +/- 1.1 mm Hg/L/min, respectively). Although the pulmonary circulatory effects were not immediate, with no detectable changes after 1 min NO inhalation, Ppa and PVR fell significantly (-19.1 +/- 10.5%, p < 0.02 and -29.3 +/- 15.1%, p < 0.02, respectively) after 10 min NO inhalation. Moreover, the extent of the NO-induced reduction in Ppa was found to depend on the level of baseline pulmonary arterial hypertension. No systemic circulatory effects were observed. The mean VA/Q ratio and the dispersion of ventilation and blood flow distributions were not altered by NO inhalation, although there was a significantly higher percentage of ventilation (7.3 +/- 7.3%, p < 0.05) in poorly and unperfused areas (VA/Q > 10).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗

PubMed1993

Pulmonary diffusing capacity after maximal exercise.

To determine the effect of maximal exercise on alveolocapillary membrane diffusing capacity (Dm), 12 professional handball players aged 23.4 +/- 3.3 (SD) yr were studied before and during early recovery from a progressive maximal exercise [immediately (t0), 15 min, and 30 min (t30) after exercise]. Lung capillary blood volume and Dm were determined in a one-step maneuver by simultaneous measurement of CO and NO lung transfer (DLCO and DLNO, respectively) with use of the single-breath breath-hold method. At t0, DLCO was elevated (13.1 +/- 12.0%; P < 0.01) but both DLNO and Dm for CO remained unchanged. Between t0 and t30, both DLCO and DLNO decreased significantly. At t30, DLCO was not different from the control resting value. DLNO (and consequently Dm for CO) was significantly lower than the control value at t30 (-8.9 +/- 8.1%; P < 0.01). Lung capillary blood volume was elevated at t0 (18.0 +/- 19.0%; P < 0.01) but progressively decreased to near control resting values at t30. Differences in the postexercise kinetics of both DLCO and DLNO point to a role of the transient increase in pulmonary vascular recruitment during the recovery period. We concluded that Dm was somewhat decreased in the 30 min after maximal exercise of short duration, but the exact pulmonary mechanisms involved remain to be elucidated.

Adult↗

PubMed1993

Membrane diffusion of the lungs in patients with chronic renal failure.

Patients with chronic renal failure (CRF) and haemodialysis treatment usually have a reduced CO transfer factor. The aim of this study was to evaluate the effects of alveolar wall fibrosis and of anaemia on gas diffusion in the lungs. The NO and CO transfer factors of the lung (TLNO and TLCO) were measured, simultaneously, in 15 patients haemodialysed three times a week for 1-10 yrs. Assuming that NO is highly reactive with blood, Tlno is thus directly proportional to the membrane diffusion factor (DmCO). The lung capillary blood volume (Vc) was derived from the set of the two transfer equations. Transfer factors were measured between haemodialysis sessions. All patients but one were anaemic, with haemoglobin concentrations ranging 61-151 g.l-1. All had decreased Vc, and a decreased DmCO was observed in 14 patients. However, after correction for the anaemia, Vc values were normal with the exception of three patients. The percentage decrease in DmCO with respect to normal was correlated with the time elapsed since the first haemodialysis. These results support the idea of a progressive development of haemodialysis-induced chronic lung disease, that may be related to a mechanism of complement activation by a bio-incompatible membrane (Cuprophane). Accordingly, patients with compromised cardiopulmonary functions should be dialysed with a bio-compatible membrane.

Anemia↗

PubMed1991

Pulmonary diffusion limitation after prolonged strenuous exercise.

To determine the effect of strenuous prolonged exercise on alveolo-capillary membrane diffusing capacity, 11 marathon runners aged 37 +/- 7 years (mean +/- SD) were studied before and during early recovery (28 +/- 14 min) from a marathon race. Lung capillary blood volume (Vc) and the alveolo-capillary diffusing capacity (Dm) were determined in a one-step maneuver by simultaneous measurements of CO and NO lung transfer (DLCO and DLNO, respectively) using the single breath, breath-holding method. After the race, both DLCO and DLNO were significantly decreased in all subjects (-10.9 +/- 4.8%, P less than 10(-4) and -29.0 +/- 11.1%, P less than 10(-4), respectively). The mean value of the derived DmCO decreased by -29.3 +/- 11.1%, whereas Vc had not entirely returned to control resting value. Although these results do not indicate the detailed mechanism involved, interstitial lung fluid was suspected to accumulate, particularly in alveoli, during the race. We concluded that the high overall work load and the extended duration of the exercise both contributed to a transient change in the structure of the alveolo-capillary membrane thereby affecting the diffusing capacity of the alveolo-capillary membrane.

Adult↗

PubMed1991

[A new form of mushroom workers' lung].

The authors describe a new form of mushroom workers' lung after assessing the clinical situation and also the results of an immunological study. The case was related to the mushroom Poria megalopora. A new antigen has been identified and also its domiciliary origin, thus the ubiquitous nature of the antigen contributes to the interest of the case reported.

Alveolitis, Extrinsic Allergic↗

PubMed1990

Determination of lung capillary blood volume and membrane diffusing capacity in patients with COLD using the NO-CO method.

Lung capillary blood volume (Qc) and the membrane diffusing capacity (Dm) can both be determined from the combined measurement of nitric oxide (NO) and carbon monoxide (CO) transfers using the single-breath method. In ten healthy subjects, no differences was observed between the values of transfer factor of the lungs for carbon monoxide (TLCO) recovered after a 3 s or 9 s breath-holding time (tBH). The NO-CO method could thus be used with a short tBH and a low fraction of inspired nitric oxide (FINO) (8 ppm). However, in ten patients with chronic obstructive lung disease (COLD), the values of both transfer factor of the lungs for nitric oxide (TLNO) and TLCO were underestimated by around 20% at a short tBH (3 s). In COLD patients, the NO-CO method therefore requires a longer tBH and a higher inspired fraction of NO (30 ppm) than in healthy subjects. Similar values of Dm and Qc were obtained using the NO-CO method and the two-step conventional method, at two levels of the oxygenation. The former method gave less scatter. Furthermore, TLNO is independent of the fraction of inspired oxygen (FIO2) and directly proportional to carbon monoxide membrane diffusing capacity (DmCO).

Adult↗