Biomedical subjects

Fabienne Bregeon

Publications and source records attributed to Fabienne Bregeon.

8 recordsLinked to original sources

PubMed2006

Hemodynamics in experimental gastric juice induced aspiration pneumonitis.

OBJECTIVE: To characterize hemodynamic changes during experimental aspiration pneumonitis, paying special attention to echocardiographic assessment. DESIGN AND SETTING: Animal study in a university-based research laboratory. SUBJECTS: Fourteen mechanically ventilated New Zealand white rabbits INTERVENTIONS: We instilled 1 ml/kg human gastric juice (mean pH: 4.1+0.2) intratracheally. Hemodynamic and respiratory parameters were measured every hour for 4 h, associated with a transthoracic echocardiography. MEASUREMENTS AND RESULTS: Lung injury occurred within 1 hour with a marked decrease in PaO(2)/FIO(2) and an increase in plateau pressure; after this initial drop the ratio remained stable throughout the experiment. Seven rabbits experienced only a mild to moderate alteration in lung oxygenation function as defined by a PaO(2)/FIO(2) ratio above 200 (group A), while the other seven developed a severe alteration with a ratio below 200 (group B). At the end of the experiment pH and cardiac output were lower in group B than in group A. Using a PaO(2)/FIO(2) threshold value of 150, pH, mean arterial pressure, and cardiac output were lower in the animals with the more severe hypoxemia. Neither left nor right ventricular dysfunction occurred during the experiment, and no animal experienced circulatory failure CONCLUSION: Experimental aspiration pneumonitis after intratracheal infusion of human gastric juice is characterized by a stable fall in PaO(2)/FIO(2). Animals with the most severe lung injury experienced a lower systemic arterial pressure, cardiac output, and metabolic acidosis without circulatory failure or cardiac dysfunction.

Animals↗

PubMed2006

Alveolar recruitment assessed by positron emission tomography during experimental acute lung injury.

OBJECTIVES: To compare changes in aerated lung volumes measured by positron emission tomography (PET) and inflation volume-pressure curve (V-P) of the respiratory system, and to evaluate the reliability of PET to assess alveolar recruitment. DESIGN AND SETTING: Experimental study in six anesthetized and mechanically ventilated pigs in a PET facility in an experimental university laboratory. INTERVENTIONS: Lung injury was induced by oleic acid. Animals were randomly studied in four conditions: PEEP 0cmH(2)O (ZEEP) in supine position (SP), PEEP 10cmH(2)O in SP, ZEEP in prone position (PP) and PEEP in PP, each applied for 30min. MEASUREMENTS AND RESULTS: With PET aerated lung volume was obtained from pulmonary density analysis using transmission scan (VA(trans)) and from nitrogen-13 kinetics on emission scan (VA(em)). Changes in VA(trans) and VA(em) were computed as the difference in aerated volume between conditions. VA(trans) and VA(em) did not differ between SP and PP, on either ZEEP or PEEP, suggesting no modification in relaxation volume of the respiratory system induced by posture. Changes in VA(trans) or VA(em) were significantly correlated with changes in aerated volume assessed from superimposed V-P curves (R (2)=0.74 and 0.75, respectively). Alveolar recruitment assessed by PET was significantly correlated with both PaO(2) (R (2)=0.61) and PaCO(2) (R (2)=0.40) variations induced by PEEP. CONCLUSIONS: PET is a new reliable tool of scientific interest to image lung volume and alveolar recruitment during acute lung injury.

Animals↗

PubMed2006

Protective ventilation influences systemic inflammation after esophagectomy: a randomized controlled study.

BACKGROUND: Esophagectomy induces a systemic inflammatory response whose extent has been recognized as a predictive factor of postoperative respiratory morbidity. The aim of this study was to determine the effectiveness of a protective ventilatory strategy to reduce systemic inflammation in patients undergoing esophagectomy. METHODS: The authors prospectively investigated 52 patients undergoing planned esophagectomy for cancer. Patients were randomly assigned to a conventional ventilation strategy (n = 26; tidal volume of 9 ml/kg during two-lung and one-lung ventilation; no positive end-expiratory pressure) or a protective ventilation strategy (n = 26; tidal volume of 9 ml/kg during two-lung ventilation, reduced to 5 ml/kg during one-lung ventilation; positive end-expiratory pressure 5 cm H2O throughout the operative time). RESULTS: Plasmatic levels of interleukin (IL)-1beta, IL-6, IL-8, and tumor necrosis factor alpha were measured perioperatively and postoperatively. Pulmonary function and postoperative evolution were also evaluated. Patients who received protective strategy had lower blood levels of IL-1beta, IL-6, and IL-8 at the end of one-lung ventilation (0.24 [0.15-0.40] vs. 0.56 [0.38-0.89] pg/ml, P < 0.001; 91 [61-117] vs. 189 [127-294] pg/ml, P < 0.001; and 30 [22-45] vs. 49 [29-69] pg/ml, P < 0.05, respectively) and 18 h postoperatively (0.18 [0.13-0.30] vs. 0.43 [0.34-0.54] pg/ml, P < 0.001; 54 [36-89] vs. 116 [78-208] pg/ml, P < 0.001; 16 [11-24] vs. 35 [28-53] pg/ml, P < 0.001, respectively). Protective strategy resulted in higher oxygen partial pressure to inspired oxygen fraction ratio during one-lung ventilation and 1 h postoperatively and in a reduction of postoperative mechanical ventilation duration (115 +/- 38 vs. 171 +/- 57 min, P < 0.001). CONCLUSION: A protective ventilatory strategy decreases the proinflammatory systemic response after esophagectomy, improves lung function, and results in earlier extubation.

Aged↗

PubMed2005

Usefulness of ultrasonography in predicting pleural effusions > 500 mL in patients receiving mechanical ventilation.

STUDY OBJECTIVE: To assess the accuracy of chest ultrasonography in predicting pleural effusions > 500 mL in patients receiving mechanical ventilation. DESIGN: Prospective study. SETTING: Surgical and medical ICU in a teaching hospital. PATIENTS: Forty-four patients receiving mechanical ventilation with indications of chest drainage of a nonloculated pleural effusion. INTERVENTIONS: Diagnosis of pleural effusion was based on clinical examination and chest radiography. Chest drainage was indicated when considered as potentially useful for the patient (hypoxemia and/or weaning failure). Sonograms were performed before drainage at the bedside, in the supine position, and measurements were performed at the end of expiration. Effusions were classified as > 500 mL or < or = 500 mL according to the drained volume. MEASUREMENTS AND RESULTS: The drained volume ranged from 100 to 1,800 mL (mean, 730 +/- 440 mL [+/- SD]). The distance between the lung and posterior chest wall at the lung base (PLDbase) and the distance between the lung and posterior chest wall at the fifth intercostal space (PLD5) were significantly correlated with the drained volume (PLDbase, r = 0.68, p < 0.001; PLD5, r = 0.56, p < 0.001). A PLDbase > 5 cm predicted a drained volume > 500 mL with a sensitivity of 83%, specificity of 90%, positive predictive value of 91%, and negative predictive value of 82%. Interobserver and intraobserver percentages of error were, respectively, 7 +/- 6% and 9 +/- 6% for PLDbase, and 6 +/- 5% and 8 +/- 5% for PLD5. The PaO2/fraction of inspired oxygen ratio significantly increased after chest drainage in patients with collected volumes > 500 mL (p < 0.01). CONCLUSIONS: Bedside pleural ultrasonography accurately predicted a nonloculated pleural effusion > 500 mL in patients receiving mechanical ventilation using simple and reproducible measurements.

Aged↗

PubMed2004

Accuracy of the double indicator method for measurement of extravascular lung water depends on the type of acute lung injury.

OBJECTIVE: The double indicator method is sensitive to alterations in the distribution of pulmonary blood flow. This distribution is influenced by the type of lung injury. The aim of this study was to compare measurements of lung water by the double indicator method with measurements obtained by gravimetry in a direct lung injury model induced by tracheal instillation of hydrochloric acid and in an indirect lung injury model induced by the intravenous injection of oleic acid. DESIGN: Prospective, randomized laboratory study. SETTING: Animal research laboratory. SUBJECTS: Forty-two female pigs (28+/-3 kg). INTERVENTIONS: Pigs were anesthetized and ventilated and were allocated into three groups: control (n = 6), hydrochloric acid (4 mL/kg intratracheally, n = 24), or oleic acid (0.1 mL/kg intravenously, n = 12). MEASUREMENTS AND MAIN RESULTS: Hydrochloric acid instillation or oleic acid injection resulted in a similar hypoxemia and induced a two- to three-fold increase in extravascular lung water (EVLW) by gravimetry (EVLWG) at 3 hrs compared with controls. In the oleic acid group, there was a significant correlation between EVLWG and EVLW by double indicator method (EVLWDI; r =.88, p <.0001). The bias for EVLWDI - EVLWG measurements was -5.2 mL/kg (95% confidence interval, -5.7 to -4.7 mL/kg) with 95% limits of agreement of -7 to -3.4 mL/kg. In the hydrochloric acid group, there was no significant correlation between EVLWDI and EVLWG values, and the double indicator method failed to detect pulmonary edema in 65% of the animals (EVLWDI <8 mL/kg). The bias was -7.9 mL/kg (95% confidence interval, -9.3 to -6.5 mL/kg) with 95% limits of agreement of -14.4 to -1.4 mL/kg. CONCLUSIONS: The double indicator method is useful for evaluation of pulmonary edema in indirect lung injury, as induced by oleic acid, but produces misleading values in direct lung injury, as produced by hydrochloric instillation.

Analysis of Variance↗

PubMed2003

Long-term outcome in intensive care unit survivors after mechanical ventilation for intracerebral hemorrhage.

OBJECTIVE: To evaluate long-term survival and functional outcome in intensive care unit survivors after mechanical ventilation for intracerebral hemorrhage. DESIGN: Retrospective chart review and prospective follow-up study. SETTING: Outpatient follow-up. PATIENTS: Between 1997 and 2000, 120 patients were mechanically ventilated for an intracerebral hemorrhage at our intensive care unit. Sixty-two patients were discharged from hospital (in-hospital mortality = 48%). Sixty patients were evaluated for survival and functional outcome (two were lost to follow-up). Time between discharge and follow-up was > or =1 yr and was a mean of 27 +/- 14 months (range, 12-56). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Patients' physicians were first asked about survival, and patients or proxies were interviewed by phone. Barthel Index and modified Rankin Scale scores were collected, and demographic information and general data were reviewed. The estimated life-table survival curve after discharge was 64.6% at 1 yr and 57% at 3 yrs. In the 24 patients who died, the mean time between discharge and death was 5 +/- 6 months. Probability of death after discharge significantly increased if age at admission was >65 yrs (p <.01; odds ratio, 3.5; 95% confidence interval, 1.4-9.1) and if Glasgow Coma Scale score at discharge was <15 (p <.01; odds ratio, 3.9; 95% confidence interval, 1.6-9.5). In the 36 long-term survivors, Barthel Index was 67.5 +/- 15 (median +/- median absolute dispersion) and modified Rankin Scale score was 2.6 +/- 0.5. Fifteen patients (42%) had a slight or no disability (Barthel Index > or =90 and modified Rankin Scale score < or =2), whereas 21 patients (58%) had moderate or severe disability (Barthel Index < or =85 and modified Rankin Scale score >2). CONCLUSIONS: Probability of survival at 3 yrs after mechanical ventilation for an intracerebral hemorrhage was >50%. Age was an important determinant of long-term survival. Forty-two percent of long-term survivors were independent for activities of daily living. Only a few long-term survivors had a very high degree of disability.

Adult↗

PubMed2003

Cardiopulmonary effects of lipid emulsions in patients with ARDS.

STUDY OBJECTIVES: Lipid emulsions have been suspected of inducing certain modifications in gas exchange and pulmonary hemodynamics. The aim of this prospective study was to evaluate the hemodynamic and pulmonary effects of two lipid emulsions. DESIGN: Prospective, randomized, double-blind, crossover study. SETTING: Medical and surgical ICU in a French university hospital. PATIENTS: Eighteen patients presenting ARDS. INTERVENTIONS: Each patient received a 6-h infusion of a 20% fat emulsion containing 100% long-chain triglycerides (LCTs) and a 6-h infusion of 50% LCTs/50% medium-chain triglycerides (MCTs) 20% lipid emulsion at the rate of 1.0 mL/kg/h. An 18-h period with no lipids separated the two periods. An additional 18-h period after the end of the second lipid emulsion administration was observed prior to the final measurements. MEASUREMENTS AND RESULTS: The MCT/LCT emulsion increased the PaO(2)/fraction of inspired oxygen (FIO(2)) ratio (p = 0.005) compared with LCT emulsion alone. The mean (+/- SD) PaO(2)/FIO(2) ratio increased from 165 +/- 55 to 191 +/- 64 mm Hg after 1 h of LCT/MCT administration (p < 0.03), and to 175 +/- 46 mm Hg after 6 h. Moreover, there was an increase in oxygen delivery after 6 h of LCT/MCT administration (p < 0.001 vs baseline). While a time-related increase in mean pulmonary artery pressure (p = 0.012) during lipid administration was found, no effect of the kind of lipid emulsion was observed. The time-related increase in cardiac index (p = 0.002) was more marked when the patients received the LCT/MCT emulsion (p = 0.002). Pulmonary vascular resistances were not affected by the kind of lipid emulsion. CONCLUSIONS: The present work showed that while the LCT emulsion induced no deleterious effects on oxygenation in ARDS patients, the LCT/MCT emulsion improved the PaO(2)/FIO(2) ratio and had a further beneficial effect on oxygen delivery.

Cross-Over Studies↗

PubMed2002

Can the tomographic aspect characteristics of patients presenting with acute respiratory distress syndrome predict improvement in oxygenation-related response to the prone position?

BACKGROUND: In some patients with acute respiratory distress syndrome, the prone position is able to improve oxygenation, whereas in others it is not. It could be hypothesized that the more opacities that are present in dependent regions of the lung when the patient is in the supine position, the better the improvement in oxygenation is observed when the patients are turned prone. Therefore, we conducted a prospective study to identify computed tomographic scan aspects that could accurately predict who will respond to the prone position. METHODS: We included 46 patients with acute respiratory distress syndrome (31 responders and 15 nonresponders). Computed tomographic scan was performed in the 6-h period preceding prone position. Blood gas analyses were performed before and at the end of the first 6-h period of prone position. RESULTS: Arterial oxygen partial pressure/fraction of inspired oxygen increased from 117 +/- 42 (mean +/- SD) in the supine position to 200 +/- 76 mmHg in the prone position (P < 0.001). There were 31 responders and 15 nonresponders. There was a vertebral predominance of the opacities (P < 0.0001). However, there was no difference between responders and nonresponders. When only the amount of consolidated lung located under the heart was evaluated, there was more consolidated tissue under the heart relative to total lung area in nonresponders than in responders (P = 0.01). CONCLUSIONS: There are no distinctive morphologic features in the pattern of lung disease measured by computed tomographic scanning performed with the patient in the supine position that can predict response to the prone position.

Aged↗