PubMed Health⌕ Search

Biomedical subjects

R Rodriguez-Roisin

Publications and source records attributed to R Rodriguez-Roisin.

At least 91 records · Page 5Linked to original sources
PubMed1995

Role of bronchoalveolar lavage in the diagnosis of fat embolism syndrome.

Fat embolism syndrome (FES) is a serious clinical disorder occurring in trauma patients. The diagnosis of fat embolism syndrome may be difficult to establish clinically. We therefore wanted to investigate the usefulness of bronchoalveolar lavage (BAL) in the diagnostic evaluation of fat embolism syndrome. We analysed the presence of fat droplets in BAL cells in 32 trauma patients (7 with full diagnostic criteria of fat embolism syndrome, 17 with incomplete diagnostic criteria, and 8 with no diagnostic criteria at the time of bronchoscopy), 9 nontrauma patients with acute respiratory failure and radiographic pulmonary infiltrates, and a control group composed of 10 individuals. An increased percentage of oil red O positive alveolar macrophages (cut-off point > 3%) in BAL was found in 6 out of 7 patients with definite clinical criteria of fat embolism syndrome, and in 6 out of 20 trauma patients without the clinical diagnosis of fat embolism syndrome. In two patients with fat embolism syndrome, sequential BAL showed that the percentage of positive macrophages decreased when the clinical manifestations disappeared. An increased number of BAL macrophages with fat droplets was also observed in two trauma patients without evidence of fat embolism syndrome after long-bone surgical intervention. By contrast, all non-trauma patients had a percentage of positive cells lower than 3%. Our findings suggest that BAL oil red O positive macrophages are frequently observed in trauma patients irrespective of the presence of fat embolism syndrome. Conceivably, a high number of oil red O positive macrophages could reflect clinically silent fat embolization.

Adult↗
PubMed1995

Aetiology and prognostic factors of patients with AIDS presenting life-threatening acute respiratory failure.

Respiratory failure is a significant contributor to morbidity and mortality in patients with the acquired immune deficiency syndrome (AIDS). We performed a study to investigate the aetiology, prognostic factors, and short- and long-term outcome of AIDS patients with life-threatening respiratory failure and pulmonary infiltrates. Forty-two AIDS patients (29 of whom required mechanical ventilation), admitted to a Respiratory Intensive Care Unit (ICU) from 1985 to 1992 because of severe respiratory failure (arterial oxygen tension/fractional inspiratory oxygen (Pa,O2/FI,O2) ratio at hospital admission 19 +/- 14 kPa (mean +/- SD)) and diffuse pulmonary infiltrates, were studied for evaluation of the aetiology and outcome. Necropsy studies were performed in 14 out of 23 (61%) patients who died. Pneumocystis carinii was the most common aetiology of pulmonary infiltrates (28 patients (67%)). Overall, 19 patients survived (45%) and 23 (55%) died. A multivariate analysis of prognostic factors influencing the outcome of the whole population showed that the presence of P. carinii pneumonia and the requirement for mechanical ventilation (MV) were the major determinants of outcome for this type of patient. The median survival time after ICU discharge for P. carinii pneumonia patients was lower (49 days) when compared to that of the remaining patients (154 days). Median survival time after ICU discharge for patients needing MV (112 days) did not differ from that observed in patients not requiring artificial ventilatory support (154 days). Although the ICU survival rate in this study was reasonable, 55% for the whole population, and 36% for P. carinii pneumonia patients, the poor outcome after ICU discharge, in particular for P. carinii pneumonia patients, deserves the reassessment of ICU admission criteria for this type of AIDS population.

AIDS-Related Opportunistic Infections↗
PubMed1994

Utility of selective digestive decontamination in mechanically ventilated patients.

OBJECTIVE: To assess selective digestive decontamination for preventing nosocomial pneumonia and mortality in mechanically ventilated patients. DESIGN: Prospective, randomized, placebo-controlled, double-blind study. SETTING: Respiratory intensive care unit of a 1000-bed teaching hospital. PATIENTS: 80 patients receiving mechanical ventilation for more than 72 hours. INTERVENTIONS: Patients received selective digestive decontamination using polymyxin E, tobramycin, and amphotericin B through a nasogastric tube and also topically in the oropharynx; control patients received placebo. All patients received intravenous cefotaxime for 4 days or other systemic antibiotics if required. MEASUREMENTS: Bacteriologic surveillance (three times a week) was done by quantitatively culturing tracheal aspirates, pharyngeal swabs, and gastric juice. The diagnosis of pneumonia was based on quantitative cultures of protected specimen brush samples (> or = 10(3) CFU/mL [colony forming units/mL]) or bronchoalveolar lavage fluid (> or = 10(4) CFU/mL) and autopsy findings. RESULTS: Bronchial, oropharyngeal, and gastric colonization by gram-negative bacilli and Candida species was lower in the selective digestive decontamination group compared with the placebo group. Nonsignificant differences were found in the incidence of nosocomial infections (28% compared with 37%; odds ratio, 0.66; 95% CI, 0.35 to 1.25) and nosocomial pneumonia (18% compared with 24%; odds ratio, 0.7; CI, 0.33 to 1.46) and in the crude mortality rate (31% compared with 27%; odds ratio, 1.21; CI, 0.63 to 2.34) when comparing digestive decontamination with placebo, respectively. CONCLUSIONS: Selective digestive decontamination in our mechanically ventilated patients significantly decreased the colonization rate of gram-negative bacilli and of Candida species but not of Staphylococcus aureus. It did not decrease the incidence of nosocomial pneumonia, mortality, length of stay, or the duration of mechanical ventilation.

Adult↗
PubMed1994

Gas exchange during weaning in patients with chronic obstructive pulmonary disease.

In patients with chronic obstructive pulmonary disease (COPD), weaning from mechanical ventilation further aggravates ventilation-perfusion (VA/Q) inequalities. This is related to the development of an abnormal ventilatory pattern, characterized by rapid and shallow breathing, but also to the increase of cardiac output secondary to an abrupt increase in venous return to the lungs. These changes are not associated with further hypoxemia because of the complex interplay between intrapulmonary (i.e., VA/Q mismatch) and extrapulmonary factors (overall ventilation and cardiac output). Cardiac dysfunction together with oxygen consumption can influence arterial PO2 and alter the balance between intrapulmonary and extrapulmonary determinants of arterial blood gases resulting in further hypoxemia and causing unsuccessful weaning.

Carbon Dioxide↗
PubMed1994

Effect of sampling site on femoral venous blood gas values.

To examine whether the tip of the femoral vein catheter used for sampling femoral venous PO2 during cycling exercise is contaminated by skin or saphenous vein blood, we studied 6 healthy volunteers [21.7 +/- 0.7 (SD) yr] during three identical incremental exercise tests while breathing room air on the same day. Femoral venous blood was sampled simultaneously from two catheters inserted into the femoral vein but advanced in opposite directions (7 cm distally and 5 cm proximally). Blood sampling for measurements of PO2, PCO2, pH, hemoglobin concentration, and oxyhemoglobin saturation was done simultaneously from both catheters in duplicate at rest, at 60% of maximum workload (60% W), and at maximum symptom-limited exercise (100% W). Temperature was measured with a thermistor probe placed in the proximal catheter. At rest, distal PO2 was significantly lower than that measured proximally (24.9 +/- 4.3 vs 30.8 +/- 6.1 mmHg, respectively; P < 0.004), but no differences were found during exercise (60% W, 23.6 +/- 3.4 vs. 24.5 +/- 3.6 mmHg; 100% W, 26.0 +/- 3.6 vs. 25.5 +/- 2.8 mmHg, respectively). Comparison of blood temperatures between proximal and distal sites of sampling in two subjects showed negligible differences. Intrasubject coefficient of variation of distal femoral venous PO2 over the three bouts of exercise was 11.5% (2.9 mmHg) at rest, 5.9% (1.4 mmHg) at 60% W, and 5.6% (1.5 mmHg) at 100% W. Mean differences in distal PO2 between duplicate samples were 0.5 +/- 1.4 mmHg at rest, 0.1 +/- 0.8 mmHg at 60% W, and 0.6 +/- 0.9 mmHg at 100% W.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Validation of different techniques for the diagnosis of ventilator-associated pneumonia. Comparison with immediate postmortem pulmonary biopsy.

To assess the accuracy of clinical parameters for the diagnosis of ventilator-associated (VA) pneumonia, as well as the diagnostic value of several invasive techniques, such as protected specimen brush (PSB), bronchoalveolar lavage (BAL), fiberoptic bronchial aspirates (FBAS), and percutaneous lung needle aspiration (PLNA), we compared the results of these techniques with the histopathology of immediate postmortem pulmonary biopsies, considered the "gold standard" reference test. We studied 30 mechanically ventilated patients (age 52 +/- 21 yr; mechanical ventilation period 9 +/- 7 days) who died in an intensive care unit. All patients received prior antibiotic treatment. The following procedures were performed immediately after death: bilateral PSB, BAL, FBAS, and PLNA, as well as bilateral minithoracotomies to obtain pulmonary biopsies as close as possible to the area sampled with the other techniques. According to the histopathology 18 patients had pneumonia and 12 did not. The presence of fever (sensitivity 55%, specificity 58%), purulent secretions (sensitivity 83%, specificity 33%), and chest radiograph infiltrates (sensitivity 78%, specificity 42%) could not differentiate in all instances presence from absence of pneumonia. Quantitative bacterial cultures of lung biopsies using 10(3) cfu/g as a cutoff point had low sensitivity (40%) and low specificity (45%) and could not differentiate the histologic absence or presence of pneumonia. Considering the histopathology of pulmonary biopsies as a gold standard, we found the following sensitivities for PSB, BAL, FBAS, and PLNA: 36, 50, 44, and 25%. The specificities were 50, 45, 48, and 79%, respectively. The sensitivities and specificities of different invasive techniques are much lower than those reported in clinical studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Bacterial Agents↗
PubMed1994

Pulmonary vascular abnormalities and ventilation-perfusion relationships in mild chronic obstructive pulmonary disease.

Morphologic changes in pulmonary muscular arteries may modify the mechanisms that regulate the pulmonary vascular tone and contribute to maintaining an adequate ventilation-perfusion (VA/Q) matching in patients with chronic obstructive pulmonary disease (COPD). To analyze the relationships between the abnormalities of pulmonary muscular arteries and the degree of VA/Q inequality, and to assess the effect of these abnormalities on the changes in VA/Q relationships induced by oxygen breathing, we studied a group of patients with mild COPD undergoing resective lung surgery. According to the degree of airflow obstruction and the increase in VA/Q mismatch produced by 100% O2 breathing (delta logSD Q), patients were divided into three groups: (A) patients with normal lung function, (B) patients with airflow obstruction and a high response to oxygen (delta logSD Q > 0.4), and (C) patients with airflow obstruction and a low response to oxygen (delta logSD Q < 0.4). Pulmonary arteries in Groups B and C showed narrower lumens and thicker walls than in Group A. These morphologic changes were produced mainly by an enlargement of the intimal layer and were more pronounced in Group C than in Group B. The assessment of intimal area as a function of artery diameter showed that the increase in intima in Group C took place predominantly in arteries with small diameters (< 500 microns). The mean intimal area on each subject correlated with both the PaO2 value (r = -0.46, p < 0.05) and the overall index of VA/Q mismatching (r = 0.51, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1994

Effects of PEEP on VA/Q mismatching in ventilated patients with chronic airflow obstruction.

Recent work in patients with acute respiratory failure (ARF) due to exacerbation of chronic airflow obstruction (CAO) suggests that application of low degrees of positive end-expiratory pressure (PEEP) can improve rather than impair respiratory mechanics, because PEEP replaces intrinsic PEEP (PEEPi). However, the impact of PEEP on pulmonary gas exchange has not been fully investigated. We designed this study to examine the effects of PEEP and those of PEEPi on ventilation/perfusion (VA/Q) mismatching in mechanically ventilated patients with CAO. Eight patients were studied under four conditions: (1) during controlled mechanical ventilation with the ventilatory setting established by the attending physicians (PEEPi-100%), according to standard criteria; (2) after application of PEEP amounting to 50% (PEEP-50%), and then (3) to 100% (PEEP-100%) of the original PEEPi; and finally, (4) after reduction of PEEPi to 50% of the initial value (PEEPi-50%), obtained by increasing expiratory time and decreasing respiratory rate and tidal volume. Respiratory mechanics, hemodynamics, respiratory blood gases, and VA/Q distributions were measured during each ventilatory mode. At low values of PEEP (PEEP-50%) no changes in respiratory mechanics nor in hemodynamics were observed, but PaO2 moderately increased (from 103 +/- 25.2 to 112 +/- 29.6 mm Hg) and PaCO2 slightly decreased (from 42 +/- 3.7 to 40 +/- 3.3 mm Hg) essentially because of an increase in the mean VA/Q ratio (first moment) of both flood flow (Q, from 0.65 +/- 0.28 to 0.78 +/- 0.29) and ventilation (V, from 4.02 +/- 1.55 to 4.93 +/- 2.00) distributions (p < 0.05, each).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Inhaled platelet-activating factor worsens gas exchange in mild asthma.

To investigate the potential effects of inhaled platelet-activating-factor (PAF) (12 micrograms) to perturb pulmonary gas exchange in bronchial asthma, six patients (mean +/- SE, 23 +/- 2 yr) with intermittent asthma (FEV1, 90% predicted) were studied before and 5, 15, and 45 min after challenge. Circulating white blood cells, respiratory system resistance (Rrs), systemic and pulmonary hemodynamics, and respiratory and inert pulmonary gas exchange were measured. Five minutes after PAF leukocytes fell, Rrs increased (by 27%). PaO2 decreased (by 15 mm Hg), and AaPO2 increased (twofold) (p < 0.05 each). Ventilation-perfusion (Va/Q) distributions worsened in a pattern similar to that commonly observed in patients with moderate to severe asthma. Dispersions of pulmonary blood flow (log SD Q) and of alveolar ventilation (log SD V), and an overall index of Va/Q heterogeneity (DISP R-E*) increased significantly (123% for DISP R-E*; p < 0.05, each). Gas exchange indices and Rrs were still minimally abnormal at 15 min but returned towards baseline at 45 min. Ventilatory and hemodynamic variables remained unaltered throughout the study. These results suggest that endogenous PAF may be implicated in the arterial blood gas abnormalities shown during exacerbations of bronchial asthma.

Administration, Inhalation↗
PubMed1994

Ventilator-associated pneumonia by Staphylococcus aureus. Comparison of methicillin-resistant and methicillin-sensitive episodes.

All episodes of ventilator-associated pneumonia (VAP) caused by Staphylococcus aureus were prospectively analyzed for a 30-mo period. Methicillin-sensitive S. aureus (MSSA) was isolated in 38 episodes and methicillin-resistant S. aureus (MRSA) in 11 others. The two groups were similar regarding sex, severity of underlying diseases, prior surgery, and presence of renal failure, diabetes, cardiopathy, and coma. MRSA-infected persons were more likely to have received steroids before developing infection (relative risk [RR] = 3.45, 95% confidence interval [CI] = 1.38-8.59), to have been ventilated > 6 d (RR = 2.03, 95% CI = 1.36-3.03), to have been older than 25 yr (RR = 1.50, 95% CI = 1.09-2.06), and to have had preceding chronic obstructive pulmonary disease (RR = 2.76, 95% CI = 0.89-8.56) than MSSA-infected patients. MSSA-infected persons were more likely than MRSA-infected patients to have cranioencephalic trauma (RR = 1.94, 95% CI = 1.22-3.09). All patients with MRSA VAP had previously received antibiotics, compared with only 21.1% of those with MSSA infection (p < 0.000001). The incidence of empyema was similar in both groups; nevertheless, the presence of bacteremia and septic shock was more frequent in the MRSA group. Finally, mortality directly related to pneumonia was significantly higher among patients with MRSA episodes (RR = 20.72, 95% CI = 2.78-154.35). This analysis was repeated for monomicrobial episodes, and the difference remained statistically significant. We conclude that MRSA and MSSA strains infect patients with different demographic profiles; previous antibiotic therapy is the most important risk factor for developing MRSA infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Platelet-activating factor causes ventilation-perfusion mismatch in humans.

We hypothesized that platelet-activating factor (PAF), a potent inflammatory mediator, could induce gas exchange abnormalities in normal humans. To this end, the effect of aerosolized PAF (2 mg/ml solution; 24 micrograms) on ventilation-perfusion (VA/Q) relationships, hemodynamics, and resistance of the respiratory system was studied in 14 healthy, nonatopic, and nonsmoking individuals (23 +/- 1 [SEM]yr) before and at 2, 4, 6, 8, 15, and 45 min after inhalation, and compared to that of inhaled lyso-PAF in 10 other healthy individuals (24 +/- 2 yr). PAF induced, compared to lyso-PAF, immediate leukopenia (P < 0.001) followed by a rebound leukocytosis (P < 0.002), increased minute ventilation (P < 0.05) and resistance of the respiratory system (P < 0.01), and decreased systemic arterial pressure (P < 0.05). Similarly, compared to lyso-PAF, PaO2 showed a trend to fall (by 12.2 +/- 4.3 mmHg, mean +/- SEM maximum change from baseline), and arterial-alveolar O2 gradient increased (by 16.7 +/- 4.3 mmHg) (P < 0.02) after PAF, because of VA/Q mismatch: the dispersion of pulmonary blood flow and that of ventilation increased by 0.45 +/- 0.1 (P < 0.01) and 0.29 +/- 0.1 (P < 0.04), respectively. We conclude that in normal subjects, inhaled PAF results in considerable immediate VA/Q inequality and gas exchange impairment. These results reinforce the notion that PAF may play a major role as a mediator of inflammation in the human lung.

Adolescent↗
PubMed1994

Clinical and functional assessment of patients with idiopathic pulmonary fibrosis: results of a 3 year follow-up.

The purpose of this study was to analyse the information provided by different techniques used in the assessment of patients with idiopathic pulmonary fibrosis (IPF) and their role in the prediction of lung function decline with the decline. Twenty seven subjects with IPF (55 +/- 14 (mean +/- SD) yrs) were studied at the initial staging. Nineteen of them (70%) were included in a follow-up over 3 yrs (32 +/- 6 months), whilst the remaining 8 patients were lost to follow-up. During the period of the study, 6 of the 19 patients died. A significant correlation between diffusing capacity of the lungs for carbon monoxide (DLCO) (and carbon monoxide transfer coefficient (KCO) = DLCO/alveolar volume (VA)) and the increase in alveolar-arterial oxygen tension difference (A-aPO2) during exercise (delta A-aPO2) was observed at diagnosis (r = -0.58). Despite the treatment with prednisone (1 mg.kg-1 daily during 4 weeks, tapered to an individualized maintenance daily dose of 15-30 mg), the 13 patients controlled throughout the whole period of the study showed a marked impairment in lung volumes; forced vital capacity (FVC) -0.46 +/- 0.09 l, from 69 +/- 16 to 52 +/- 11% of predicted, and total lung capacity (TLC) -0.39 +/- 0.11 l, from 75 +/- 16 to 62 +/- 14%, and in DLCO -0.6 +/- 0.2 mmol.min-1.kPa-1, from 56 +/- 15 to 47 +/- 18%, predicted. By contrast, both mean arterial oxygen tension (PaO2) and A-aPO2 at rest remained unchanged throughout the 3 yrs follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
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↗