Biomedical subjects

Robert Rodriguez-Roisin

Publications and source records attributed to Robert Rodriguez-Roisin.

7 recordsLinked to original sources

PubMed2005

Effect of transjugular intrahepatic portosystemic shunt on pulmonary gas exchange in patients with portal hypertension and hepatopulmonary syndrome.

AIM: To assess the impact of transjugular intrahepatic portosystemic shunt (TIPS) on pulmonary gas exchange and to evaluate the use of TIPS for the treatment of hepatopulmonary syndrome ( HPS ). METHODS: Seven patients, three of them with advanced HPS, in whom detailed pulmonary function tests were performed before and after TIPS placement at the University of Alabama Hospital and at the Hospital Clinic, Barcelona, were considered. RESULTS: TIPS patency was confirmed by hemodynamic evaluation. No changes in arterial blood gases were observed in the overall subset of patients. Transient arterial oxygenation improvement was observed in only one HPS patient, early after TIPS, but this was not sustained 4 mo later. CONCLUSION: TIPS neither improved nor worsened pulmonary gas exchange in patients with portal hypertension. This data does not support the use of TIPS as a specific treatment for HPS. However, it does reinforce the view that TIPS can be safely performed for the treatment of other complications of portal hypertension in patients with HPS.

Adult↗

PubMed2005

Identification of vascular progenitor cells in pulmonary arteries of patients with chronic obstructive pulmonary disease.

Progenitor cells of bone marrow origin migrate to injured vessels, where they may contribute to endothelial maintenance and vessel remodeling through vascular endothelial growth factor (VEGF)-related signals. To what extent progenitor cells may play a role in vascular changes occurring in patients with chronic obstructive pulmonary disease (COPD) remains undetermined. In this study we sought to identify vascular progenitor cells in pulmonary arteries of patients with COPD and to investigate whether the presence of these cells could be related to changes in endothelial function or the expression of VEGF. Pulmonary arteries of nine patients with COPD and six control subjects were studied. Scanning electron microscopy demonstrated areas of denuded endothelium in the arteries of patients with COPD. Vascular progenitor cells were identified by immunohistochemistry and immunogold using antibodies against AC133, CD34, and CD45. AC133+ cells were localized in the endothelial surface, close to denuded areas. The number of AC133+ and CD45+ cells in pulmonary arteries was greater in patients with COPD than in control subjects. The number of AC133+ cells correlated with the response of pulmonary artery rings to hypoxic stimulus. AC133+ and CD45+ cells were also identified in the intimal layer. The wall thickness correlated with the number of progenitor cells in the intima and with VEGF and VEGF receptor-2 mRNA expression. We conclude that patients with COPD show an increased number of bone marrow-derived progenitor cells in pulmonary arteries. These cells seem to contribute to ongoing endothelial repair, but they might also be involved in the pathogenesis of pulmonary vascular remodeling.

AC133 Antigen↗

PubMed2005

Encouraged 6-min walking test indicates maximum sustainable exercise in COPD patients.

STUDY OBJECTIVES: In patients with moderate-to-severe COPD, an encouraged 6-min walking test (6MWT) is a high-intensity submaximal exercise protocol that shows an oxygen uptake (Vo(2)) plateau after the third minute of the test. This last feature prompted the hypothesis that self-paced walking speed is set to achieve "maximal" sustainable Vo(2), namely "critical power" or "critical speed." PATIENTS AND METHODS: Eight patients with moderate-to-severe COPD (mean age, 68 +/- 7 years [+/- SD]; FEV(1), 50 +/- 13% predicted; Pao(2), 69 +/- 8 mm Hg) underwent the following tests on different days in order: (1) encouraged 6MWT; (2) standard incremental shuttle test to identify peak walking speed; (3) four different high-intensity, constant walking speed tests to exhaustion to calculate critical walking speed; and (4) timed walking test at critical walking speed (CWS) to examine sustainability of the exercise. RESULTS: 6MWT and CWS showed similar results (mean of last 3 min): Vo(2) (1,605 +/- 304 mL/min vs 1,584 +/- 319 mL/min), minute ventilation (47 +/- 12 L/min vs 48 +/- 11 L/min), respiratory exchange ratio (0.89 +/- 0.1 vs 0.90 +/- 0.1), heart rate (130 +/- 18 beats/min vs 131 +/- 16 beats/min), Borg dyspnea score (5.4 +/- 1.3 vs 5.5 +/- 2.4), and walking speed (1.49 +/- 0.1 m/s vs 1.44 +/- 0.1 m/s, respectively). CONCLUSION: This study supports that 6MWT indicates maximum sustainable exercise that might be related with its predictive value in COPD patients.

Aged↗

PubMed2004

Clinical value of vasodilator test with inhaled nitric oxide for predicting long-term response to oral vasodilators in pulmonary hypertension.

Acute vasodilator tests with prostacyclin (PGI2) or inhaled nitric oxide (iNO) are used to select patients with pulmonary arterial hypertension (PAH) who should be treated with oral vasodilators. The haemodynamic effects of PGI2 and iNO are different, and the limits for considering a vasodilator response as significant are controversial. The study was aimed to investigate the diagnostic performance of acute vasodilator testing with iNO and PGI2 in predicting the clinical outcome after 1 year treatment with oral vasodilators. Twenty-seven patients with severe PAH were studied. Nineteen patients were treated with oral vasodilators and their outcome after 1 year was qualified as favourable or unfavourable. The diagnostic performance of vasodilator tests in predicting this outcome was evaluated using receiver operating characteristics (ROC) curves. The acute effects of iNO and PGI2 on pulmonary artery pressure (PAP) were similar. By contrast, PGI2 produced more marked changes on cardiac output and pulmonary vascular resistance than iNO (P<0.05). The evolution at 1 year was favourable in 11 patients and unfavourable in 8. Patients with favourable evolution showed greater decrease of PAP with iNO than with PGI2 (P<0.05). The decrease of PAP with iNO had the greatest predictive value on the clinical outcome (area under ROC curve, 0.83). We conclude that in patients with PAH, acute vasodilator testing with iNO is preferable to PGI2 because it reflects more consistently the changes in pulmonary vascular tone. The acute decrease of PAP with iNO is the best predictor of the long-term response to oral vasodilator treatment.

Administration, Inhalation↗

PubMed2003

Noninvasive ventilation during persistent weaning failure: a randomized controlled trial.

To assess the efficacy of noninvasive ventilation (NIV) in patients with persistent weaning failure, we conducted a prospective, randomized, controlled trial in 43 mechanically ventilated patients who had failed a weaning trial for 3 consecutive days. This trial was stopped after a planned interim analysis. Patients were randomly extubated, receiving NIV (n = 21), or remained intubated following a conventional-weaning approach consisting of daily weaning attempts (n = 22). Compared with the conventional-weaning group, the noninvasive-ventilation group had shorter periods of invasive ventilation (through tracheal intubation) (9.5 +/- 8.3 vs. 20.1 +/- 13.1 days, p = 0.003) and intensive care unit (ICU) (14.1 +/- 9.2 vs. 25.0 +/- 12.5 days, p = 0.002) and hospital stays (27.8 +/- 14.6 vs. 40.8 +/- 21.4 days, p = 0.026), less need for tracheotomy to withdraw ventilation (1, 5% vs. 13, 59%, p < 0.001), lower incidence of nosocomial pneumonia (5, 24% vs. 13, 59%, p = 0.042) and septic shock (2, 10% vs. 9, 41%, p = 0.045), and increased ICU (19, 90% vs. 13, 59%, p = 0.045) and 90-day survival (p = 0.044). The conventional-weaning approach was an independent risk factor of decreased ICU (odds ratio: 6.6; p = 0.035) and 90-day survival (odds ratio: 3.5; p = 0.018). Earlier extubation with NIV results in shorter mechanical ventilation and length of stay, less need for tracheotomy, lower incidence of complications, and improved survival in these patients.

Aged↗

PubMed2003

Enhanced expression of vascular endothelial growth factor in pulmonary arteries of smokers and patients with moderate chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) is associated with structural and functional changes in the pulmonary circulation that commence at an early stage. To investigate whether vascular endothelial growth factor (VEGF) might be implicated as a mediator in COPD-associated pulmonary vascular changes, we studied surgical specimens obtained from 19 nonsmokers, 21 smokers with normal lung function, 28 patients with moderate COPD, and 10 patients with severe emphysema. The expression of VEGF in pulmonary muscular arteries was evaluated by immunohistochemistry, its protein content in lung tissue by Western blot analysis, and VEGF mRNA and its isoforms were analyzed by reverse transcription-polymerase chain reaction. The immunohistochemical expression of VEGF was increased in pulmonary arteries of smokers (median, 68% [interquartile range, 60-88]) and patients with moderate COPD (77% [63-82]), compared with nonsmokers (53% [40-63]) (p < 0.05 each). The expression of VEGF in smooth muscle cells correlated with the thickness of the vessel wall (r = 0.38, p < 0.01). VEGF protein content in lung tissue was reduced in severe emphysema, where reverse transcription-polymerase chain reaction demonstrated a lower proportion of the VEGF189 isoform. In conclusion, the expression of VEGF varies according to the severity of COPD and might be involved in the pathogenesis of pulmonary vascular remodeling at early stages of the disease.

Aged↗

PubMed2002

Pulmonary gas exchange response to weaning with pressure-support ventilation in exacerbated chronic obstructive pulmonary disease patients.

OBJECTIVE: To assess if pressure-support ventilation (PSV) can improve ventilation-perfusion (V(A)/Q) imbalance observed during the transition from positive-pressure ventilation to spontaneous breathing in intubated chronic obstructive pulmonary disease (COPD) patients during weaning. DESIGN: Prospective study. SETTING: Respiratory intensive care unit of a tertiary university hospital. PATIENTS: Seven mechanically ventilated COPD male patients (age 68+/-6 (SD) years; FEV(1) 26+/-6% predicted) during weaning. INTERVENTIONS: Patients were studied during three ventilatory modalities: (1) assist-control ventilation (ACV), tidal volume (V(T)), 8-10 ml. kg(-1); (2) PSV aimed to match V(T)in ACV, 15+/-1 cmH(2)O and (3) spontaneous breathing. MEASUREMENTS AND RESULTS: Arterial and mixed venous respiratory blood gases, V(A)/Q distributions, hemodynamics and breathing pattern were measured. Compared with both ACV and PSV, during spontaneous breathing patients exhibited decreases in V(T) (of 43%, p<0.001) and increases in respiratory rate (of 79%, p<0.001), PaCO(2) (of 8.5 mmHg, p=0.001), cardiac output (of 27%, p<0.001) and mixed venous oxygen tension (of 3.4 mmHg, p=0.003), while PaO(2) remained unchanged throughout the study. Except for a shift of the pulmonary blood flow distribution to areas with lower V(A)/Q ratios (p=0.044) and an increase of dead space (of 25%, p=0.004) during spontaneous breathing, no other changes in V(A)/Q distributions occurred. No differences were shown between ACV and PSV modalities. CONCLUSION: In COPD patients during weaning, PSV avoided V(A)/Q worsening during the transition from positive-pressure ventilation to spontaneous breathing. Hemodynamics, blood gases or V(A)/Q mismatch were no different between ACV and PSV when both modalities provided similar levels of ventilatory assistance.

Aged↗