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Biomedical subjects

R Rossaint

Publications and source records attributed to R Rossaint.

At least 127 records · Page 7Linked to original sources
PubMed1997

[Perspectives in mechanical ventilation in ARDS].

Despite more than 25 years of extensive research, the mortality of ARDS patients remains high. The inflammatory process within the lung and the associated gas exchange disturbances require an aggressive ventilatory regimen, which itself may harm the lung. Therapeutic measures which are used to reduce iatrogenic damage to the lung are pressure controlled mechanical ventilation in combination with PEEP and permissive hypercapnia, dehydration and extracorporeal gas exchange. At present, new strategies such as intratracheal instillation of surfactant, partial liquid ventilation and inhalation of nitric oxide (NO) are being evaluated. Surfactant reduces the surface tension, forming a monomolecular layer at the air/tissue interface. It thereby decreases the forces necessary to expand the alveoli and prevents alveoli with small diameter from collapsing. In ARDS, a disturbance of surfactant synthesis, function and re-uptake is the rationale for treatment with exogenous surfactant. Initial clinical results suggest a limited positive effect independently of the surfactant preparation used, the dose and the application mode. Experience with partial liquid ventilation with perfluorocarbons in ARDS has also been reported. Perfluorocarbons are liquids with a high binding capacity for oxygen and carbon dioxide. During normal mechanical ventilation with gas, repetitive doses of perfluorocarbons are instilled into the lungs up to a volume equal to the functional residual capacity. The liquid is pushed into collapsed alveoli and keeps them open by reducing the surface tension. First clinical studies have demonstrated the possible improvement in pulmonary gas exchange. In ARDS, inhalation of NO may cause a predominantly selective vasodilation in blood vessels of ventilated lung regions, resulting in an increase in PaO2 and a decrease in pulmonary artery pressure. The effect of NO on the pulmonary vasculature also induces a reduction in right ventricular afterload and also in pulmonary capillary pressure, which may lead to a faster resolution of pulmonary edema. However, in spite of the promising results of these new strategies, further studies are needed to evaluate their influence on morbidity and mortality.

Combined Modality Therapy↗
PubMed1997

High survival rate in 122 ARDS patients managed according to a clinical algorithm including extracorporeal membrane oxygenation.

OBJECTIVE: We investigated whether a treatment according to a clinical algorithm could improve the low survival rates in acute respiratory distress syndrome (ARDS). DESIGN: Uncontrolled prospective trial. SETTING: One university hospital intensive care department. PATIENTS AND PARTICIPANTS: 122 patients with ARDS, consecutively admitted to the ICU. INTERVENTIONS: ARDS was treated according to a criteria-defined clinical algorithm. The algorithm distinguished two main treatment groups: The AT-sine-ECMO (advanced treatment without extracorporeal membrane oxygenation) groups (n = 73) received a treatment consisting of a set of advanced non-invasive treatment options, the ECMO treatment group (n = 49) received additional extracorporeal membrane oxygenation (ECMO) using heparin-coated systems. MEASUREMENTS AND RESULTS: The groups differed in both APACHE II (16 +/- 5 vs 18 +/- 5 points, p = 0.01) and Murray scores (3.2 +/- 0.3 vs 3.4 +/- 0.3 points, p = 0.0001), the duration of mechanical ventilation prior to admission (10 +/- 9 vs 13 +/- 9 days, p = 0.0151), and length of ICU stay in Berlin (31 +/- 17 vs 50 +/- 36 days, p = 0.0016). Initial PaO2/FIO2 was 86 +/- 27 mm Hg in AT-sine-ECMO patients that improved to 165 +/- 107 mm Hg on ICU day 1, while ECMO patients showed an initial PaO2/FIO2 of 67 +/- 28 mm Hg and improvement to 160 +/- 102 mm Hg was not reached until ICU day 13. QS/QT was significantly higher in the ECMO-treated group and exceeded 50% during the first 14 ICU days. The overall survival rate in our 122 ARDS patients was 75%. Survival rates were 89% in the AT-sine ECMO group and 55% in the ECMO treatment group (p = 0.0000). CONCLUSIONS: We conclude that patients with ARDS can be successfully treated with the clinical algorithm and high survival rates can be achieved.

Adult↗
PubMed1997

[Aerosolized prostacyclin for preoperative evaluation and post-cardiosurgical treatment of patients with pulmonary hypertension].

BACKGROUND: Inhaled nitric oxide (NO) has been shown to selectively lower pulmonary vascular resistance and is applied in patients with pulmonary hypertension (PHT). However, application and monitoring is complex and not always successful ("non-responders"). We evaluated the effect of aerolized prostacyclin (aePGI2) as a therapeutic alternate to NO. PATIENTS AND METHODS: aePGI2 and NO were applied to patients with different causes of pulmonary hypertension (Group 1a: preoperative patients with intracardiac shunting defects and Eisenmenger's disease, n = 30; Group 1b: patients with primary or postoperative PHT, n = 13; Group 2: PHT immediately following surgery for congenital heart disease, n = 6). RESULTS: Pulmonary vascular resistance could be lowered significantly (Group 1a: from 91% of systemic vascular resistance to 58% with NO and 53% with aePGI2; Group 1b: from 20.2 Wood Units*m2 to 13.4 and 11.3; Group 2: from 24.9 Wood Units*m2 to 9.5 and 10.5); cardiac index increased (Group 1b: from 2.96 to 3.55 and 3.96 l/min*m2, Group 2: from 1.57 to 1.89 and 2.00 l/min*m2). CONCLUSIONS: The short-term application of aePGI2 shows a selective pulmonary vasodilation similar to NO. Given adequate monitoring, aePGI2 appears to be useful for the acute treatment of PHT.

Administration, Inhalation↗
PubMed1997

Extracorporeal membrane oxygenation for transport of hypoxaemic patients with severe ARDS.

Conventional inter-hospital transfer of patients with severe acute respiratory distress syndrome (ARDS) in need of extracorporeal membrane oxygenation (ECMO) may be risky and in severe hypoxaemic patients may be associated with cerebral hypoxia and death. Therefore, we began a phase 1 study to evaluate the feasibility, complications and outcome of inter-hospital transport of these patients using veno-venous ECMO. Eight patients with severe ARDS and a PaO2/FIO2 < 6.7 kPa at a PEEP > or = 10 cm H2O were placed on a mobile ECMO at the referring hospital. The 495 (SD 123) km inter-hospital transport via a special ground ambulance took 341 (151) min. After transfer, blood-gas tensions were improved in spite of less optimal ventilator settings, compared with data before the start of ECMO. No significant complications occurred. Six patients survived and were discharged from hospital; two patients died because of multiple organ failure. We conclude that initiation of ECMO in hypoxaemic patients before inter-hospital transfer is feasible and enables safe transport to an ECMO centre.

Adult↗
PubMed1997

Partial liquid ventilation with small volumes of FC 3280 increases survival time in experimental ARDS.

The aim of this study was to determine the prolonged effects of sequential doses of a highly purified perfluorocarbon (FC 3280) on gas exchange and survival time in experimental acute respiratory distress syndrome (ARDS). The study was prospective, randomized and controlled. Twelve pigs (body weight 30 +/- 5 (mean +/- SD) kg) were surfactant-depleted by repetitive lung lavages, reducing arterial oxygen tension (Pa,O2) to 6.9 +/- 1.6 kPa (52 +/- 12 mmHg) (mean +/- SD) at an inspired oxygen fraction (Fi,O2) of 1.0. They were then randomized to receive partial liquid ventilation by sequential intratracheal application of 7.5 mL.kg-1 FC 3280 at 30 min intervals to a cumulative dose of 15 mL.kg-1 (treatment group), or to receive no further treatment (control group). Haemodynamics and gas exchange were assessed at 30 min intervals after instillation, and hourly afterwards in both groups until death. In the treatment group, Pa,O2 was 8.9 +/- 4.4 kPa (67 +/- 33 mmHg) after 7.5 mL.kg-1 FC 3280 and 14.1 +/- 9.9 kPa (106 +/- 74 mmHg) after 15 mL.kg-1 FC 3280 (NS). In the control group, gas exchange remained unchanged. Haemodynamics were stable in the treatment group and deteriorated in the control group. Peak airway pressures and dynamic compliance were not significantly affected in the treatment group. Mean survival time was 8.2 +/- 4.5 h in the treatment group and 1.8 +/- 1.4 h in the control group (p < 0.05). Upon histological examination, both study groups were not significantly different in total lung injury scores. We conclude that partial liquid ventilation with small volumes of FC 3280 provides improvement in gas exchange and increases survival time in experimental acute respiratory distress syndrome.

Animals↗
PubMed1997

Coagulation techniques are not important in directing blood product transfusion during liver transplantation.

Preoperative acquired clotting parameters such as prothrombin time, activated partial thromboplastin time, antithrombin III, platelet concentration, and fibrinogen show coagulopathy caused by insufficiency of the diseased liver. Intraoperative determination of clotting factors or parameters is not helpful to direct intraoperative transfusion of blood, blood components, or platelets because transfusions performed solely for correction of clotting data do not correlate with the real intraoperative requirements and increase the costs of orthotopic liver transplantation. However, the use of antihyperfibrinolytic drugs seems to reduce intraoperative blood loss. Patients with cirrhotic disorders caused by portalvenous hypertension show extensive collaterals and increased intravascular blood volume. Thus it is plausible that especially overcorrection of blood loss during the surgical preparation in the preanhepatic phase of the operation results in extensive blood loss. Therefore, to avoid blood loss we attempt to keep volume substitution to a minimum during the preanhepatic phase of the operation. In contrast, during the anhepatic and postanhepatic phases we attempt to reestablish normovolemia by transfusing red packed blood cells and fresh-frozen plasma. Strictly confined use of blood products in the preanhepatic phase, followed by later correction of intravascular blood volume, may reduce intraoperative blood loss; it also seems to ensure adequate substitution of clotting factors.

Blood Coagulation↗
PubMed1997

Effect of a hybrid liver support system on cardiopulmonary function in healthy pigs.

The aim of this study was to evaluate the effects of a hybrid liver support system (LSS) on cardiopulmonary function in nine healthy pigs. A hybrid LSS containing primary pig hepatocytes was connected to fully alert animals. The extracorporeal blood flow was maintained between 200-240 ml/min using a roller pump. Continuous plasma flow through the hybrid LSS was 50-60 ml/min. Hemodynamic and pulmonary gas exchange parameters were compared 1 hour before and 1 hour after connection to as well as 1 hour before and 1 hour after disconnection from the hybrid LSS. The hybrid LSS did not influence significantly hemodynamics and pulmonary gas exchange in this group of healthy and awake pigs. It can be concluded that the used LSS did not cause a cardiopulmonary effect per se and should be evaluated further concerning its function as a liver support system in an animal model of acute hepatic failure.

Animals↗
PubMed1996

Cytokine pattern during rejection and infection after liver transplantation--improvements in postoperative monitoring?

Despite improvements in immunosuppression, rejection occurs in 50% of liver transplant patients and may cause significant morbidity. The most frequent cause of death after liver transplantation is severe infection. Determination of the cytokine network may lead to earlier detection of patients at risk for severe rejection and infection. For this purpose, 81 patients with 85 liver transplants were monitored for cytokines and neopterin on a daily basis. During the first postoperative month, 28 patients (34.6%) developed acute rejection; 14 patients were successfully treated with methylprednisolone (steroid-sensitive rejection), while 14 patients required additional treatment with FK506 and OKT3 (steroid-resistant rejection). Ten patients developed severe infections, and 11 patients experienced asymptomatic cholangitis. Patients with an uneventful postoperative course (n=37) were the control group. One-year patient survival was 88.9%: 1 patient died because of chronic rejection and Pseudomonas urosepsis; a further 4 patients died of aspergillus pneumonia and bacterial sepsis. Soluble TNF-RII, sIL-2R-, and IL-10 levels were significantly elevated 3 days prior to or at the onset of acute steroid-resistant rejection (P < or = 0.01 versus steroid-sensitive rejection and on uneventful postoperative course). An increase in IL-8, neopterin, and sTNF-RII was indicative of severe infection 3 days prior to onset of infection. In this group of patients, a simultaneous increase in IL-10 indicated a lethal outcome of severe infection. During the second week of acute steroid-resistant rejection and lethal infection, a significant rise in IL-1beta, IFN-gamma, and IL-6 was observed (P < or = 0.01 versus control groups). The different patterns in neopterin- and cytokine-increase could differentiate between severe rejection and severe infection. Furthermore, the increase in these parameters indicated severe rejection--i.e., steroid resistance at the onset of acute rejection--which could prompt us to initiate rescue therapy immediately. The ability to detect patients at risk for severe or lethal infection may result in intensified infectious screening and more aggressive antiinfectious treatment. Therefore, routine monitoring of these parameters may lead to changes in therapeutic management of severe acute rejection and infection after liver transplantation.

Alanine Transaminase↗
PubMed1996

Nitroglycerin versus epoprostenol: effects on hemodynamics, oxygen delivery, and hepatic venous oxygenation after liver transplantation.

Our objective was to determine the effects of vasodilatory treatment with epoprostenol (PGI2) and nitroglycerin (NTG) on systemic oxygen delivery index (DO2) and hepatic venous oxygen saturation (SvhO2) after liver transplantation. This prospective study used repeated-measures design. Fifteen adult patients undergoing orthotopic liver transplantation (OLT) were enrolled. Postoperatively, a fiberoptic pulmonary artery catheter was inserted into the right hepatic vein and a timed infusion of PGI2 and NTG was sequentially performed in random order at the following rates: PGI2 at 5 ng/kg/minute and NTG at 0.1 microgram/kg/minute. Each step in each sequence lasted 45 minutes, followed by a control interval of 45 minutes. Measurements were taken at the end of each period when hemodynamic function was stable. Systemic hemodynamics, DO2, oxygen uptake index (VO2), mixed venous oxygen saturation (SvO2), and SvhO2 were assessed. We found that PGI2 induced an increase of cardiac index (+18%, p < .05); DO2 (+16%, p < .05); and SvhO2 (+11%, p < .05). Mean arterial pressure was decreased during PGI2 infusion (-9%, p < .05), as well as during infusion of NTG (-10%, p < .05). NTG significantly decreased DO2 (-6%, p < .05) and SvhO2 (-4%, p < .05). Neither drug affected VO2. We conclude that PGI2 induced vasodilation and increased systemic oxygen delivery in parallel with SvhO2, suggesting a corresponding increase of hepatic oxygen supply. NTG induced systemic vasodilation and significantly impaired hepatic venous oxygen saturation and DO2. Thus, if vasodilatory therapy is indicated in the patient after liver transplantation, PGI2 appears to be better than NTG in improving DO2 without impairing splanchnic oxygenation.

Adult↗
PubMed1996

Dopamine, dopexamine and dobutamine in liver transplant recipients: a comparison of their effects on hemodynamics, oxygen transport and hepatic venous oxygen saturation.

The purpose of this study was to determine the effects of vasoactive treatment with dopamine (DO), dopexamine (DX), and dobutamine (DOB) on hemodynamics, oxygen transport and hepatic venous oxygen saturation (SvhO2) after orthotopic liver transplantation (OLT). A pulmonary artery catheter was inserted into the right hepatic vein of 17 OLT patients. Timed infusion of DO, DX, and DOB was performed at the following rates: DO at 4 and 8 micrograms/kg per minute, DX at 4 and 8 micrograms/kg per minute, and DOB at 5 and 10 micrograms/kg per minute. Hemodynamics, oxygen transport variables, and SvhO2 were assessed. Each catecholamine induced a significant increase in cardiac index, oxygen delivery, and SvhO2. Mean arterial pressure was increased during DO and DOB, but significantly reduced during DX. Each inotrope increased oxygen delivery in parallel with SvhO2, suggesting a corresponding increase in hepatic oxygen supply. Therefore, it appears that each vasoactive drug may be utilized in OLT patients to provide oxygen delivery without impairment of splanchnic oxygenation.

Adult↗
PubMed1996

Aerosolized prostacyclin and inhaled nitric oxide in septic shock--different effects on splanchnic oxygenation?

OBJECTIVES: To compare the effects of inhaled nitric oxide and aerosolized prostacyclin (PGI2) on hemodynamics and gas exchange as well as on the indocyanine-green plasma disappearance rate and gastric intramucosal pH in patients with septic shock. DESIGN: Prospective, randomized, interventional clinical study. SETTING: Intensive care unit in a university hospital. PATIENTS: Sixteen patients with pulmonary hypertension and septic shock according to the criteria of the ACCP/SCCM consensus conference all requiring norepinephrine and/or epinephrine to maintain mean arterial blood pressure above 65 mmHg. METHODS AND INTERVENTIONS: Patients were randomly assigned to receive either nitric oxide or aerosolized prostacyclin. Nitric oxide was inhaled using a commercially available delivery system, prostacyclin was administered with a modified ultrasound nebulizer. Both nitric oxide and prostacyclin were incrementally adjusted to obtain a 15% decrease of mean pulmonary artery pressure. Hemodynamics and gas exchange as well as indocyanine-green plasma disappearance rate and gastric intramucosal pH were determined at baseline after 90 min in steady state, after 90 min of nitric oxide inhalation or prostacyclin aerosol administration had elapsed in stable conditions, and after 90 min in stable conditions after nitric oxide or prostacyclin withdrawal. RESULTS: Both inhaled nitric oxide and aerosolized prostacyclin selectively reduced the mean pulmonary artery pressure from 35 +/- 4, 30 +/- 4 mmHg (p < 0.05) and 34 +/- 4 to 30 +/- 3 mmHg (p < 0.05) respectively; after removal of nitric oxide and prostacyclin, the mean pulmonary artery pressure returned to the baseline values. Systemic hemodynamics remained unaltered during the vasodilator treatment. While the mean PaO2 was not significantly influenced, it increased in 4/8 of the NO- and 3/8 of the PGI2-treated patients. Neither of the drugs influenced indocyanine-green plasma disappearance rate, but prostacyclin--unlike nitric oxide--significantly increased gastric intramucosal pH (from 7.26 +/- 0.07 to 7.30 +/- 0.05, p < 0.05) which remained elevated in four of these patients after prostacyclin removal, and decreased the arterial-gastric mucosal pressure of carbon dioxide gap from 19 +/- 6 to 15 +/- 4 mmHg (p < 0.05). CONCLUSIONS: Our data suggest that aerosolized prostacyclin--unlike nitric oxide--has similar beneficial effects on splanchnic perfusion and oxygenation as intravenous prostacyclin without detrimental effects on systemic hemodynamics. The different effects of prostacyclin and nitric oxide might be explained by the longer half-life of prostacyclin associated with a certain spillover into the systemic circulation.

Administration, Inhalation↗
PubMed1996

[Clinical aspects of acute lung failure in adults (ARDS)].

Acute respiratory distress syndrome (ARDS) is rare but beset with a high mortality rate. In recent years, however, a trend towards higher survival rates has been observed. High inspiratory oxygen concentrations, large tidal volumes, and high peak inspiratory airway pressures applied during mechanical ventilation have been identified as harmful to the lung and can contribute to the progression of ARDS. This had led to reconsideration of the sequelae of ventilatory therapy. Mechanical ventilation and other adjunctive strategies in ARDS have changed from the conventional approach aiming at normalisation of physiological ventilatory parameters to an elaborated approach that intends to protect the ventilated lung, prevent oxygen toxicity, recruit the infiltrated atelectatic and consolidated lung and reduce the anatomical and alveolar dead space. This new approach consists of various forms of pressure-controlled mechanical ventilation with PEEP and permissive hypercapnia, body position changes, and inhalation of nitric oxide. Should these procedures fail to improve impaired gas exchange, extracorporeal membrane oxygenation is an additional therapeutic option. None of these therapeutic procedures, however, has been tested against traditional standard treatment in a classical randomised controlled trial. The following review focuses on the latest insights into the pathophysiology, diagnosis, and treatment of ARDS.

Combined Modality Therapy↗