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Biomedical subjects

R Rodriguez-Roisin

Publications and source records attributed to R Rodriguez-Roisin.

At least 109 records · Page 6Linked to original sources
PubMed1994

Arterial oxygenation does not predict the outcome of patients with acute respiratory failure needing mechanical ventilation.

One hundred and eighteen patients consecutively submitted to mechanical ventilation during a one year period, and admitted to the Respiratory Intensive Care Unit of the Hospital Clinic of Barcelona, were prospectively studied in order to define the importance of hypoxaemia as a predictor of mortality. Using a discriminant multivariate analysis, the following variables were selected as the best predictors of outcome: 1) the number of associated complications (NAC) on admission; 2) the simplified acute physiologic score (SAPS); 3) oxygenation index (PAO2-AaPO2)/PAO2 + 0.014 positive end-expiratory pressure (PEEP); and 4) the age of the patients. Using these predictors, 84% of the patients were accurately classified as survivors or as nonsurvivors. The partial contribution of each predictor to the model was also assessed using a logistic regression, by eliminating each single predictor and each possible pair of predictors. Using this means of analysis, the NAC and SAPS were the only predictors of mortality. The inclusion of short-term mechanically-ventilated patients did not bias the accuracy of prediction.

Aged↗
PubMed1994

Is severe arterial hypoxaemia due to hepatic disease an indication for liver transplantation? A new therapeutic approach.

Severe arterial hypoxaemia or deteriorating pulmonary oxygenation due to HPS appears to be reversible within months of orthotopic liver transplantation. Due to the apparently poor prognosis in these patients, such abnormal oxygenation may, indeed, be considered an indication for liver transplantation in selected clinical situations. The pretransplant distinction between HPS and pulmonary hypertension as a reason for arterial hypoxaemia is essential, however, in that different outcomes appear to exist. Further prospective studies of patients with pulmonary vascular complications of liver disease are desperately needed.

Adolescent↗
PubMed1994

Pulmonary gas exchange in acute respiratory failure.

The principal function of the lung is to facilitate the exchange of the respiratory gases, oxygen (O2) and carbon dioxide (CO2). When the lung fails as a gas exchanger respiratory failure ensues. Clinically, it is generally accepted that an arterial oxygen tension (PaO2) of less than 60 mmHg or a PaCO2 of greater than 50 mmHg, or both, whilst breathing room air are values consistent with the concept of respiratory failure. This article will deal, firstly, with some basic aspects of the physiology of pulmonary gas exchange and more specifically on the measurement of ventilation-perfusion (VA/Q) relationships, the most influential factor determining hypoxaemia. The second part highlights the most important findings on pulmonary gas exchange in the adult respiratory distress syndrome (ARDS) and other common acute respiratory failure conditions, such as pneumonia, acute exacerbation of chronic obstructive pulmonary disease (COPD) and status asthmaticus, based on the data obtained by means of the multiple inert gas elimination approach, a technique which gives a detailed picture of VA/Q ratio distributions.

Acute Disease↗
PubMed1993

Airway obstruction and ventilation-perfusion relationships in acute severe asthma.

We have investigated the time course of ventilation-perfusion (VA/Q) mismatch and airflow obstruction in 18 patients with acute severe asthma with the objective to identify potential differences according to the clinical severity of the attacks. Nine patients were hospitalized and nine were discharged (emergency room stay < 24 h) according to the clinical criteria of the attending physicians. Spirometry and VA/Q inequality (multiple inert gas technique) were measured within the first 6 h of treatment in the emergency room, and at Weeks 1,2,3, and 4 thereafter. In the emergency room [corrected] hospitalized patients (in relation to those discharged) showed lower airflow rates (FEV1, 31 +/- 3 versus 46 +/- 6% predicted SEM) and greater VA/Q mismatch (as assessed by the dispersion of blood flow distributions (logSD Q) (1.28 +/- 0.11 versus 0.92 +/- 0.11; normal values < 0.6). Even though the rate of improvement of airflow was similar in both groups (without returning to normal limits), VA/Q relationships improved at different rates in each group and reached normal values at the end of the study. Although in hospitalized patients the recovery of VA/Q abnormalities was delayed in relation to airflow rates, the time course in discharged patients was the same. Previous studies have shown a dissociation between spirometry and VA/Q inequality, suggesting that whereas airflow rates predominantly reflect bronchoconstriction of large airways, VA/Q mismatch is more related to obstructive changes in peripheral airways. Our results support this hypothesis and suggest that the more severe the asthma attacks, the more severe the obstructive changes involving peripheral airways for a given degree of widespread airway narrowing.

Acute Disease↗
PubMed1993

Gastric and pharyngeal flora in nosocomial pneumonia acquired during mechanical ventilation.

We studied the interrelations between gastric, pharyngeal, proximal, and distal airway bacterial flora in ventilator-associated pneumonia (VAP) on 36 patients with nosocomial pneumonia acquired during mechanical ventilation (MV) and 27 mechanically ventilated control subjects without pulmonary infection. Gastric, pharyngeal, and endotracheal (EA) sampling for quantitative cultures were performed upon all patients, as well as fiberoptic bronchoscopy with protected specimen brush (PSB) sampling. Mean bacterial and fungi colony counts were significantly increased in pharyngeal, EA, and PSB samples in patients with VAP compared with control subjects. The overall increase in colonization was due to gram-positive cocci in all samples. In addition, gram-negative bacilli and fungi mean counts increased significantly in PSB pneumonia samples versus control samples. However, mean gastric colonization was similar in both patients with VAP and control subjects. In the former group there was an increase in coincident microorganisms isolated from gastric, pharyngeal, and EA samples in relation to PSB samples compared with control samples. Among the different quantitative cultures analyzed, only those obtained from EA significantly correlated with PSB cultures in patients with pneumonia (r = 0.67, p = 0.001). In summary, the present study shows that the coincidence between microorganisms isolated in PSB cultures and those from gastric and oropharynx increase in MV patients with pneumonia, indicating that both reservoirs play a key role in the pathogenesis of pneumonia. Conceivably, preventing both gastric and pharyngeal colonization may reduce the incidence of ventilator-associated pneumonia. From all the noninvasive samples studied only endotracheal aspirate cultures were useful for inferring the etiology of some VAP pneumonias.

Bacteria↗
PubMed1993

Quantitative cultures of endotracheal aspirates for the diagnosis of ventilator-associated pneumonia.

Bronchoalveolar lavage (BAL) and protected specimen brushing (PSB) are the most commonly used methods for diagnosing ventilator-associated (VA) pneumonia although they require bronchoscopy. Endotracheal aspiration (EA) is a simple and less costly technique than PSB or BAL. The purpose of our study was to investigate the diagnostic value of EA quantitative cultures and to compare the results obtained using EA with those obtained using PSB and BAL in mechanically ventilated patients with or without pneumonia. We prospectively studied 102 intubated patients divided into three diagnostic categories: Group I (definite pneumonia, n = 26), Group II (uncertain status, n = 48), and Group III (control group, n = 28). All patients received prior antibiotic treatment. EA, PSB, and BAL were obtained sequentially in all patients. When comparing Group I with Group III and using 10(5) cfu/ml as a threshold, we found that EA quantitative cultures represented a relatively sensitive (70%) and relatively specific (72%) method to diagnose VA pneumonia. The specificity of BAL and PSB (87% and 93%, respectively) was better than that of EA. The negative predictive value of EA cultures was higher (72%) when compared with that obtained using PSB (34%) (p < 0.05). EA quantitative cultures correlated with PSB and BAL quantitative cultures in patients with definite pneumonia. Although EA quantitative cultures are less specific than PSB and BAL for diagnosing VA pneumonia, our results suggest that the former approach may be used to treat these patients when bronchoscopic procedures are not available.

Bacteria↗
PubMed1993

Effect of pulmonary hypertension on gas exchange.

This paper reviews the effects of pulmonary artery hypertension on gas exchange by exploring three different issues, namely: 1) how does gas exchange behave in diseases characterized by increased vascular tone (primary pulmonary hypertension (PPH), chronic obstructive pulmonary disease (COPD) and interstitial pulmonary fibrosis (IPF)) or decreased vascular tone ("hepatopulmonary syndrome"); 2) how does exercise, as a non-pharmacological tool of increasing pulmonary blood flow, modify gas exchange in these diseases; and 3) how do several drugs that lower (vasodilators) or increase (almitrine) the active component of pulmonary hypertension interact with gas exchange. Available data show that: 1) in PPH a high pulmonary vascular tone enhances gas exchange and when it is lowered, either by oxygen or vasodilators, ventilation perfusion (VA/Q) distributions deteriorate; 2) in COPD a lowered (vasodilators) or augmented (almitrine) active vascular tone is almost invariably paralleled by a deterioration or enhancement of ventilation-perfusion matching, respectively; 3) in IPF an adequate active response of the pulmonary vasculature is essential to maintain gas exchange, both at rest and during exercise; and 4) in patients with liver cirrhosis a low pulmonary vascular tone induces an abnormal VA/Q distribution. In summary, these data show that any situation and/or therapeutic intervention that lowers the active vascular tone deteriorates VA/Q relationships and vice versa. The final effect of pulmonary vascular tone on arterial oxygen tension (PaO2) is less predictable. The reason for this uncertainty is that the actual PaO2 value depends on the interplay of the intra- and extrapulmonary factors that control gas exchange in humans, and not only on the degree of VA/Q mismatching.

Exercise↗
PubMed1993

BAL lymphocyte activation antigens and diffusing capacity are related in mild to moderate pulmonary sarcoidosis.

To investigate the relationship [corrected] between immunocytological features of bronchoalveolar lavage (BAL) and clinical indices in sarcoidosis, we studied the lymphocyte subsets, as well as the expression of human leucocyte antigen-DR (HLA-DR) and interleukin 2 receptor (IL-2R) antigens in BAL lymphocytes. We studied 16 patients with untreated sarcoidosis and 12 control subjects. We found significantly higher absolute numbers of lymphocytes bearing the IL-2R antigen in sarcoidosis. A stronger difference between groups was observed in both the percentage and absolute numbers of HLA-DR+ lymphocytes. We also found a moderate but significant correlation between the number of lymphocytes expressing the activation antigens and single breath carbon monoxide diffusing capacity in patients with sarcoidosis: DLCO vs HLA-DR+ lymphocytes (r = -0.60); DLCO vs IL-2R+ lymphocytes (r = -0.62); carbon monoxide transfer coefficient (KCO vs HLA-DR+ lymphocytes (r = -0.53); and KCO vs IL-2R+ lymphocytes (r = -0.58). Our results suggest that the reduction in diffusing capacity, expressed as either DLCO or KCO, results from the severity of alveolitis in mild to moderate sarcoidosis.

Adult↗
PubMed1992

Interstitial pulmonary fibrosis with and without associated collagen vascular disease: results of a two year follow up.

BACKGROUND: Interstitial pulmonary fibrosis is a disease with a highly variable clinical course. To ascertain if an inadequate selection of patients might explain part of this variability, two different groups of patients with interstitial pulmonary fibrosis, those with the "lone" form of the disease (LIPF) and those with associated collagen vascular disorders (AIPF), were studied separately. METHODS: Twenty consecutive patients (nine with LIPF and 11 with AIPF) were included. Their clinical and radiographic findings and results of pulmonary function tests, gallium-67 lung scanning, and cellular analysis of bronchoalveolar lavage fluid were compared at diagnosis. Moreover, the evolution of LIPF and AIPF was contrasted after a follow up of two years, both groups having received a similar treatment regimen of corticosteroids. RESULTS: At enrollment, patients with LIPF and AIPF were of similar age, and had similar symptoms and derangement of lung function, but patients with LIPF presented with finger clubbing, more obvious radiographic abnormalities, and a greater percentage of eosinophils in bronchoalveolar lavage fluid. Two years later, patients with LIPF had significantly decreased FVC, FEV1, TLC, TLCO, and PaO2. By contrast, lung function remained unaltered in patients with AIPF. Similarly, when the percentage change from entry to the study was compared, patients with LIPF showed a significant decrease in FVC, FEV1, and PaO2. CONCLUSIONS: Unlike the patients with AIPF, those with LIPF showed a deterioration in lung function and developed further restrictive impairment and poorer gas exchange. This has implications in their clinical management.

Adult↗
PubMed1992

Pulmonary complications after long term amiodarone treatment.

BACKGROUND: Amiodarone hydrochloride is an antiarrhythmic agent useful in arrhythmias refractory to standard therapy. Although interstitial pneumonitis is known to be its most serious side effect, several aspects of amiodarone lung toxicity are still controversial. METHODS: Pulmonary side effects were examined in a sample of 61 symptomless patients (mean (SD) age 55 (7) years) who had had long term treatment with amiodarone (daily maintenance dose 400 mg), selected from 482 men attending the University of Barcelona myocardial infarction project. To allow for the confounding effects of coronary artery disease and tobacco history on lung function, 46 patients who had taken amiodarone for more than one year were matched with a control group from the same population. Subjects underwent measurement of lung volumes, arterial blood gas analysis and an incremental bicycle exercise test. RESULTS: Most lung function values were close to predicted values, though there was a small increase in resting alveolar-arterial oxygen tension difference (A-aDO2) at rest (4.8 (1.4) kPa in both groups). There were no differences in the results of forced spirometry or static lung volumes between the two groups, or in the fall in A-aDO2 from rest to exercise. There was a small difference between the amiodarone and the control group in transfer factor for carbon monoxide corrected for lung volume (KCO 1.67 (0.3) and 1.83 (0.3) mmol min-1 kPa-1 l-1 respectively) and in exercise capacity (140 (25) and 120 (30)w). Only three patients showed lung function impairment consistent with pneumonitis. No relation between lung function measures and cumulative doses of amiodarone or desethylamiodarone was found. CONCLUSIONS: The prevalence of clinically evident pulmonary side effects was 4.9%, which is lower than that reported in studies in which higher daily maintenance doses of amiodarone were given. The slightly lower KCO values and lower work load achieved by the patients taking amiodarone suggest a small effect of amiodarone in doses of 400 mg on lung function. A role for individual susceptibility to pulmonary complications of amiodarone treatment is suggested.

Amiodarone↗
PubMed1992

Effects of training on muscle O2 transport at VO2max.

To quantify the relative contributions of convective and peripheral diffusive components of O2 transport to the increase in leg O2 uptake (VO2leg) at maximum O2 uptake (VO2max) after 9 wk of endurance training, 12 sedentary subjects (age 21.8 +/- 3.4 yr, VO2max 36.9 +/- 5.9 ml.min-1.kg-1) were studied. VO2max, leg blood flow (Qleg), and arterial and femoral venous PO2, and thus VO2leg, were measured while the subjects breathed room air, 15% O2, and 12% O2. The sequence of the three inspirates was balanced. After training, VO2max and VO2leg increased at each inspired O2 concentration [FIO2; mean over the 3 FIO2 values 25.2 +/- 17.8 and 36.5 +/- 33% (SD), respectively]. Before training, VO2leg and mean capillary PO2 were linearly related through the origin during hypoxia but not during room air breathing, suggesting that, at 21% O2, VO2max was not limited by O2 supply. After training, VO2leg and mean capillary PO2 at each FIO2 fell along a straight line with zero intercept, just as in athletes (Roca et al. J. Appl. Physiol. 67: 291-299, 1989). Calculated muscle O2 diffusing capacity (DO2) rose 34% while Qleg increased 19%. The relatively greater rise in DO2 increased the DO2/Qleg, which led to 9.9% greater O2 extraction. By numerical analysis, the increase in Qleg alone (constant DO2) would have raised VO2leg by 35 ml/min (mean), but that of DO2 (constant Qleg) would have increased VO2leg by 85 ml/min, more than twice as much. The sum of these individual effects (120 ml/min) was less (P = 0.013) than the observed rise of 164 ml/min (mean). This synergism (explained by the increase in DO2/Qleg) seems to be an important contribution to increases in VO2max with training.

Adaptation, Physiological↗
PubMed1991

Mechanisms of abnormal gas exchange in patients with pneumonia.

The mechanisms of abnormal gas exchange in patients with pneumonia and the gas exchange response while breathing high inspired O2 concentrations have not been clearly elucidated. To this end, we studied 23 inpatients with pneumonia and mild to severe arterial hypoxemia and/or increased alveolar - arterial O2 difference. Ventilation-perfusion (VA/Q) distributions were obtained upon breathing room air (or maintenance inspired oxygen fraction) and 100% O2 in random order. Subjects were divided in two groups according to whether they were spontaneously breathing (SB, n = 13) or their lungs were mechanically ventilated (MV) because of acute severe respiratory failure (n = 10). The SB patients showed only small amounts of shunt (7 +/- 2%) (mean +/- standard error) and moderate VA/Q mismatching, characterized by the presence of a small percentage of blood flow to low VA/Q units (VA/Q less than 0.1) (4 +/- 1%). In contrast, patients whose lungs were MV had larger shunts (22 +/- 5%) and greater percent of perfusion to low VA/Q units (11 +/- 5%). While breathing 100% O2, shunt remained unchanged but the dispersion of the pulmonary blood flow distribution (log SDQ) (normal range, 0.3-0.6) increased in each group (from 1.04 +/- 0.10 to 1.29 +/- 0.13 in SB and from 1.40 +/- 0.11 to 1.64 +/- 0.14 in MV; P less than 0.05 each), suggesting release of hypoxic pulmonary vasoconstriction.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗