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Biomedical subjects

J Bréant

Publications and source records attributed to J Bréant.

11 recordsLinked to original sources
PubMed2001

[Pulmonary circulatory amputation in chronic respiratory insufficiency. Simple, anodyne, and fast evaluation].

UNLABELLED: In chronic respiratory insufficiency, vascular bed amputation is a key element of the prognosis. The assessment of the carbon monoxide transfer capacity of the lungs is often impossible for technical reasons. However, the measurement of CO uptake (VCO), normalized by the reject of CO2 (VCO2) is a straightforward and repeatable measure for most healthy individuals. Its deficit is most likely due to either a circulatory impairment of the "gas-exchanging organ" and/or an alveolary ventilation failure. AIM: To define the relationship between hypoxemia and VCO/VCO2 deficit. METHOD: The subjects were classified into four causes of the disease: pneumonectomy, kyphoscoliosis, emphysema and chronical bronchitis. VCO/VCO2 was measured with an open circuit and simultaneous arterial blood-gas analysis. RESULTS: With a few exceptions, VCO/VCO2 deficit was always observed and more important that hypoxemia. VCO/VCO2 and PaO2 values were not related in the case of emphysema, but strongly correlated and proportionally impaired in both pneumonectomy and kyphoscoliosis cases. CONCLUSION: This rapid, simple and well-tolerated measurement of VCO/VCO2 could provide a much-improved method of prognosis over the current CO measures.

Aged↗
PubMed1998

[Pulmonary gas transfer in pediatrics (carbon monoxide and dioxide)].

UNLABELLED: In pediatrics, measurements of gaseous transfer in steady-state (SS) are easily applied. Nevertheless, interpretation of results is uncertain because predicted values depend on numerous metabolic and ventilatory parameters. In healthy subjects, the only invariant parameter of reference, beside the blood gas, is the CO uptake (VCO) when normalized by the reject of CO2 (VCO2). Theoretically, a deficit of VCO/VCO2 (VCOSpecifique = SpVCO) should not be observed on a young asthmatic in remission. Such a deficit should be due to either a circulatory impairment of the "gas-exchanging organ" or an alveolary ventilation failure. However, the respiratory equivalent for CO2 (V/VCO2) increases in case of hyperventilation. When not observed at rest, hyperventilation can occur at exercise, that can again induce a non specific bronchitic hyperreactivity. AIM: To define links: 1) between the spirometry of the young asthmatic and the value of ERCO2 and CO tests; 2) between a circulatory anomaly and the value of SpVCO. PATIENTS AND METHOD: The asthmatic adolescents aged between 10 and 20 were separated from infants (age < 10) and classified in three degrees of spirometrical alteration according to the maximum expiratory flow when 25% of the forced vital capacity remains in the lung (V25) and the residual volume (RV); 48 adolescents were examined at rest and 17 were exercising on a cyclo-ergometer. Two adolescents with circulatory anomaly, one by idiopathic pulmonary hemosiderosis (IPH), the other by agenesia of the left lung were examined at rest and exercise. RESULTS: In asthmatics at rest the three degrees of spirometric alteration differed from one another in ERCO2 and classical CO tests; SpVCO alone was not altered at rest or during exercise. However the deficit of SpVCO, confirmed during the exercise, was significant in HPI. CONCLUSION: Simple and quick simultaneous measurements of (FICO-FECO) and FECO2 allows one to detect hyperventilation of young asthmatic subjects at rest and during exercise, or can confirm a circulatory anomaly.

Adolescent↗
PubMed1993

[Gas exchange during spontaneous and controlled ventilation in obese subjects with chronic bronchitis. Value of normalized CO intake].

In obese subjects with chronic bronchitis hypercapnia by limitation of tidal volume regresses if a slow ventilatory frequency is imposed by lengthening of expiration time. But hypoxemia due to shunt effect can either be corrected by global improvement of alveolar ventilation VA or persist and become worse by low pulmonary volume ventilation which lowers VA/Q. The effect of bradypnoea on 11 elderly patients with moderate obesity has been evaluated by simultaneous measurements of blood gases, ventilatory output coefficients, gas flow rate and steady state transfer for CO. Although hypo-VA disappeared in bradypnoea, hypoxemia persisted in 5 cases, the increase of P(Aa)O2 was accentuated in 7 cases, VCO always remained in deficit compared with VCO2 (in healthy subjects at rest, VCO and VCO2 are interrelated by a proportionally constant whatever the respiratory regimen: VCO/VCO2 = specific VCO, or VCO Sp). The VCO/VA variation correlated negatively with the P(Aa)O2 variation. This study: 1) confirms the link between PaCO2 and VT and the persistence of shunt effect bradypnoea compatible with the deficit of VCO versus VCO2; 2) distinguishes the efficiency of bradypnoea in ventilation and in alveolo-capillary exchange; 3) compares the variations of VCO Sp with those of PaO2 in relation to VT; 4) defines the characteristics of respiratory insufficiency in the obese and bronchitic subjects examined, and 5) specifies the value of VCO Sp measurement in testing the controlled ventilation technique used.

Adult↗
PubMed1985

[Steady-state carbon monoxide transfer during progressive muscular exercise in patients. Relation to PaO2. Value of specific VCO].

During muscular exercise, the alveolo-capillary gas exchange reaches its optimal capacity, but taking blood for arterial blood gases is associated with certain risks and the classical criteria of CO transfer in the steady state are difficult to interpret as they are influenced by age, sex, ventilatory regime. The "specific" CO uptake (VCO Sp) does not correspond to these criteria (6). When related to the ERCO2, it allows the DuCO to be determined (4). It has the same value at the 3rd minute and at the 10th minute of constant exercise (5). Like TCO, it is correlated with the PaO2 during effort (5). In this study, a triangular exercise was performed by men aged between 45 add 55 years, smokers and former smokers, classified into 4 A: 12 healthy subjects; B: 56 cases of chronic respiratory disease; C: 9 cases of chronic obstructive airways disease (COAD); D: 12 cases of diffuse pulmonary fibrosis (DPF). Groups C and D were derived from group B. The VCO SP, TCO and DuCO were measured at each plateau of the triangular exercise. In the patients, the PaO2 was measured at the same time as the FF (CO, CO2). In the last phase of exercise (Ex. Max.): VCO Sp was more frequently altered at rest and more strongly correlated to TCO; TCO/V had the same significance as DuCO. The results of TCO, VCO Sp and DuCO were compared between groups A, C and D.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1977

[Statistical study of the correlations between spirometric data and arterial blood gas tensions. II. During a 40-watt exercise (author's transl)].

PaO2 and PaCO2, after 5 min of a 40-Watt exercise, and spirometric data have been statistically evaluated in 152 patients with chronic obstructive bronchitis. In these patients, the hypoventilation syndrome increases during exercise. The correlation between age and PaO2 is identical during rest and exercise, but the correlation between PaO2 or PaCO2 and FEV1 (% predicted) is closer during exercise than during rest. The value 50 of the FEV1 (% predicted) divides the patients into two groups: the patients who stay normocapnic and those who become hypercapnic or increase their hypercapnemia. These data show the interest of the FEV1 (% predicted) values and allow to explain the evolution of the arterial blood gas tensions during exercise.

Adult↗
PubMedDate not supplied

[Pulmonary carbon monoxide exchange constants in the "stable state" at rest in healthy non-smokers].

During simultaneous evaluation of pulmonary O2, CO2, and CO in the stable state (ES) at rest, CO volume per minute (V'CO) standardized (V'COs) for FICO = 0.001 [2, 3] can be expressed relative to simultaneous flow of "respiratory" gases (V'O2 and V'CO2) by the quotient of the gas concentrations concerned, if its is admitted that V'I = V'E. Whether at the "expired"mean E or "alveolar" A levels, these concentrations have identical paired relationships. In the strict stable state, the proposed expressions of V'CO are constants independent of age, sex, stature, and ventilatory regimen in healthy non-smokers [6]; the result is that V'COs in relation to alveolar ventilation, V'COs/V'A, which is related to V'COs/V'CO2 by PaCO2, is also a constant. When the so-called "stable" state is not a strict one, experimental arguments suggest that V'COs/V'CO2 alone is not markedly influenced by ventilatory instability. Measurements conducted by means of different biological modalities and techniques in 3 groups of healthy women of homogeneous age breathing in a semi-open circuit: 1) established the value of the constants V'COs/V'CO2, V'COs/V'O2, V'COs/V'A in the true stable state (ESV) controlled by R and by gasometry on simultaneously collected blood samples; and 2) confirmed the constant character of V'COs/V'CO2 whatever the degree of respiratory stabilization, even when the ventilatory regimen was in reality not stabilised (ENS); V'COs/V'CO2 should therefore be the only value for defining a "specific capacity of pulmonary CO exchange". V'COs/V'A appears to be related to Q'/V'A. As DuCO/(DuCO2.1,21), which measures this ratio, it is independent of age and of ventilatory frequency. Several facts indicate that the "parallelism" of modifications affecting DuCO and DuCO2 [15] is not found in all physiological and pathological circumstances.

Adult↗
PubMedDate not supplied

[Carbon monoxide intake during exercise in healthy subjects and patients (author's transl)].

During exercise, carbon monoxide intake (V'CO) is closely related to the pulmonary capacity of CO transfer in stable condition (TCO) and "could be used, according to BATES, as a normality test of the lungs" (3). V'CO standardized for FICO = 0.001 (3) (V'COs), expressed by unit of simultaneous output of V'CO2 or V'O2 should be, during exercise: 1) independent of morphometric or ventilatory factors, 2) linked linearly and negatively with log V'O2. In 12 non-smokers healthy patients aged 29 +/- 8 years, this criterium valued on semi-open circuit of low resistance at the end of a rectangular exercise is in negative and very significant correlation with log V'O2. Measurements done on the 3rd, 6th and 10th minute of the exercise did not significantly differ amongst themselves. The validity of the relationship between V'COs/V'O2 and log V'O2 is verified in aged patients or women during triangular exercise. Twenty seven patients are classified in 2 groups, whether they are affected (I) or not (II) of widespread micronodular dissemination of lungs. The measurements of TCO, V'COs/V'O2, V'COs/V'CO2 are done simultaneouly with the sampling for gasometry at rest, then at the 10th minute of an exercise with constant power. TCO modifications produced by exercise do not, on the whole, bring any new element of information while those observed on average for PaO2, V'COs/V'O2, V'CO2 very significantly differentiated the two groups. They are compatible with the hypothesis of the majority of diffusion disorders in I, of distribution in II. The interpretation of the values in relation with age is being discussed.

Adult↗