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A Meier-Hellmann

Publications and source records attributed to A Meier-Hellmann.

At least 55 records · Page 3Linked to original sources
PubMed1998

Effect of plasma and LPS on respiratory burst of neutrophils in septic patients.

OBJECTIVE: To compare the respiratory burst of neutrophils in sepsis and control patients using lipopolysaccharide (LPS), autologous plasma, and a combination of the two. DESIGN: Prospective, consecutive case study. SETTING: A 16-bed intensive care unit (ICU) in a university teaching hospital. INTERVENTIONS: None. PATIENTS: Plasma was obtained from 23 healthy patients scheduled for minor surgery immediately prior to induction of anesthesia (controls) and from 23 ICU patients within 24 h of diagnosis of sepsis or septic shock. MEASUREMENTS AND MAIN RESULTS: Respiratory burst was determined by lucigenin chemiluminescence expressed as mean +/- SEM of peak values of relative light units per neutrophil. There were no significant differences between neutrophils of septic patients and controls for the stimuli saline, phorbol myristate acetate, formyl-methionyl-leucyl-phenylalanine, and LPS alone. Septic patients showed a lower respiratory burst than controls (p < 0.05) under the following stimuli: plasma alone (5911 +/- 803 vs 15,397 +/- 3038) and LPS and plasma combined (13,857 +/- 1537 vs 23,026 +/- 2640). However, when stimulated with plasma after priming with LPS, septic patients elicited a higher value than control subjects (11,373 +/- 1758 vs 5987 +/- 1234, p < 0.05). CONCLUSIONS: (1) Some components of the plasma of septic patients may have a profound effect on neutrophil response; (2) plasma as a respiratory burst stimulus differentiates between sepsis and non-sepsis samples better than other common stimuli; (3) precautions must be taken when using plasma together with LPS because of the different response depending on whether LPS-priming precedes the plasma stimulus or both are introduced simultaneously and whether septic or nonseptic plasma is used.

Adult↗
PubMed1998

[Aspects in monitoring and treatment of gastrointestinal underperfusion in sepsis. Diagnosis and therapy of gastrointestinal underperfusion in sepsis].

Tissue hypoxia, especially in the splanchnic area, is still considered to be an important cofactor in the pathogenesis of multiple organ failure. Thus, in the treatment of septic shock the specific effects of ino-tropic drugs on the splanchnic perfusion are of particular interest. To give strict recommendations for monitoring and for therapeutic strategies in the treatment of gastrointestinal failure in patients with sepsis is difficult not only due to the lack of data on clinical outcome and organ dysfunction, but also due to some limitations in the methods applied to assess splanchnic perfusion and oxygenation. A reasonable approach in the management of splanchnic underperfusion in septic patients includes: Measurement of gastric mucosal pH or CO2-gap because it is the only method for the assessment of splanchnic perfusion which can be useful in the clinical routine. Adequate volume loading likely is the most important step in the supportive treatment of patients with septic shock. Unfortunately, what kind of fluids, endpoints, and monitoring techniques should be used is still controversial. Nevertheless, techniques allowing us to achieve and tightly control volume loading and regional perfusion, e.g. the measurement of pHi or CO2-gap, may be helpful. Patients with high DO2 have had better outcome. However, measurement of parameters assessing global and regional oxygenation may be superior than to guide therapy by DO2. To maximize DO2 by the use of very high dosages of catecholamines can be harmful. The recommendation to use dobutamine as catecholamine of first choice seems to be justified. In critically ill patients, no negative effects of norepinephrine on regional perfusion have been demonstrated provided the patient is adequately volume resuscitated and the DO2 is normal or slightly elevated. Therefore, after volume resuscitation and treatment with dobutamine, norepinephrine should be used for achieving an adequate perfusion pressure. Epinephrine and dopamine should be avoided because they seem to restribute blood flow away from the splanchnic region. There are no convincing data yet to support the routine use of low dose dopamine or dopexamine in patients with sepsis. These recommendations are limited by the lack of outcome studies and optimal methods for the assessment of splanchnic perfusion/oxygenation.

Critical Care↗
PubMed1998

Total plasma antioxidant capacity is not always decreased in sepsis.

OBJECTIVE: To compare total plasma antioxidant capacity and selected individual antioxidants in patients with varying degrees of severity of sepsis. DESIGN: A prospective, observational, consecutive case study. SETTING: A 16-bed intensive care unit (ICU) in a university teaching hospital. INTERVENTIONS: None. PATIENTS: Forty-six healthy controls, ten ICU patients, nine patients with systemic inflammatory response syndrome (SIRS), 11 septic patients, and 14 septic shock patients. Plasma was obtained in healthy patients scheduled for minor surgery immediately before anesthesia and in ICU patients within 24 hrs of admittance to the unit or diagnosis of SIRS, sepsis, or septic shock. MEASUREMENTS AND MAIN RESULTS: Using the total peroxyl radical trapping method, we found plasma antioxidant capacity to be lower in septic patients but higher in septic shock patients, as compared with controls. Bilirubin was the greatest contributor to the increase with shock, followed by uric acid. Neopterin also correlated with the peroxyl radical trapping antioxidant parameter values. CONCLUSION: Although total plasma antioxidant capacity is decreased from normal levels in septic patients, an increase in some oxidants contributes to an increased total antioxidant capacity in septic shock patients.

Adolescent↗
PubMed1997

The effects of low-dose dopamine on splanchnic blood flow and oxygen uptake in patients with septic shock.

OBJECTIVE: To assess the effects of low-dose dopamine on splanchnic blood flow and splanchnic oxygen uptake in patients with septic shock. DESIGN: Prospective, controlled trial. SETTING: University hospital intensive care unit. PATIENTS: 11 patients with septic shock, diagnosed according the criteria of the 1992 American College of Chest Physicians/Society of Critical Care Medicine consensus conference, who required treatment with norepinephrine. MEASUREMENTS AND MAIN RESULTS: Systemic and splanchnic hemodynamics and oxygen transport were measured before and during addition of low-dose dopamine (3 micrograms/kg per min). Low-dose dopamine and a marked effect on total body hemodynamics and oxygen transport. The fractional splanchnic flow at baseline ranged from 0.15 to 0.57. In 7 patients with a fractional splanchnic flow less than 0.30, low-dose dopamine increased splanchnic flow and splanchnic oxygen delivery and oxygen consumption. In 4 patients with a fractional splanchnic flow above 0.30, low-dose dopamine did not appear to change splanchnic blood flow. CONCLUSION: Low-dose dopamine has a potential beneficial effect on splanchnic blood flow and oxygen consumption in patients with septic shock, provided the fractional splanchnic flow is not already high before treatment.

Adult↗
PubMed1997

A controlled study of leukocyte activation in septic patients.

OBJECTIVE: Qualitative and quantitative evaluation of leukocyte activation in septic patients in comparison to two control groups. DESIGN: A prospective clinical study in which the leukocyte oxidative output of whole blood was measured in three groups of patients. Two chemiluminescence markers (luminol or lucigenin), indicative of either total oxidant output or superoxide production, and three stimuli (opsonized zymosan, formyl-methionyl-leucyl-phenylalanine (fMLP), phorbol myristate acetate) (PMA), representing different pathways of leukocyte activation, were used. Tumor necrosis factor, interleukin-6 and C-reactive protein (TNF, IL-6, and CRP) were determined to evaluate the severity of the inflammatory process. SETTING: Intensive care and surgical units of a university hospital. PATIENTS: Seventy-four healthy patients, ten ICU patients without signs of sepsis or systemic inflammatory response syndrome and 19 septic patients were studied. MEASUREMENT AND MAIN RESULTS: With all three stimuli, whole blood total oxidative output and superoxide production were generally increased in septic patients. This was most likely due to the increased leukocyte numbers in these patients. When the chemiluminescence values were normalized per phagocyte (granulocytes and monocytes), the total oxidative output of septic phagocytes decreased with opsonin and fMLP but increased with PMA, while superoxide output decreased regardless of the stimuli used. TNF, IL-6 and CRP, although increased in septic patients as compared to ICU controls, correlated weakly with oxidant output. CONCLUSIONS: The oxidative output of whole blood was increased in septic patients compared to controls because of elevated leukocyte numbers. However, oxidant output normalized for phagocyte numbers generally decreases during sepsis for most stimuli. Cytokines and CRP do not appear to be associated with the extent of oxidant output during sepsis.

Adult↗
PubMed1997

[Effectiveness of pulmonary artery catheterization in the critically ill patient--attempt at evaluating current status].

Pulmonary artery catheterization is currently used for more than 25 years for the hemodynamic monitoring of critically ill patients. As for every monitoring technique, its indication is based on the goal, that knowledge of the obtained additional hemodynamic parameters may lead to an optimization of therapy and thereby to an improvement in patients'outcome. Despite of the presence of clinical studies which documented changes in therapy following such extended monitoring, there is no clear proof for a positive effect on patients' mortality. While some of the available studies showed a benefit by pulmonary artery catheterization, others did not or even demonstrated a negative effect. However, no study fulfilled the scientific requirements which enables to make a statement to the effectiveness of pulmonary artery catheterization by objective criteria. The purpose of this review article is to summarize the currently available literature with regard to the effectiveness of pulmonary artery catheterization in the critically ill patient.

Catheterization, Swan-Ganz↗
PubMed1997

Epinephrine impairs splanchnic perfusion in septic shock.

OBJECTIVE: To assess the effects of epinephrine on splanchnic perfusion and splanchnic oxygen uptake in patients with septic shock. DESIGN: Prospective, controlled trial. SETTING: University hospital intensive care unit (ICU). PATIENTS: Eight patients with septic shock, according to the criteria of the 1992 American College of Chest Physicians/Society of Critical Care Medicine Consensus Conference, requiring treatment with vasopressors. INTERVENTIONS: We compared in crossover design a 2-hr infusion of epinephrine with dobutamine plus norepinephrine in eight ICU patients with septic shock. Systemic and splanchnic hemodynamics and oxygen transport were measured before and during treatment with epinephrine. MEASUREMENTS AND MAIN RESULTS: There was essentially no effect of epinephrine on the global parameters, except for increased lactate concentrations. There were marked effects on the regional variables; epinephrine caused lower splanchnic flow and oxygen uptake, lower mucosal pH, and higher hepatic vein lactate. CONCLUSION: We conclude that undesirable splanchnic effects on patients in whom that region is particularly fragile should be considered when using epinephrine for septic shock treatment.

Adult↗
PubMed1996

Splanchnic blood flow is greater in septic shock treated with norepinephrine than in severe sepsis.

OBJECTIVE: To assess global and splanchnic blood flow and oxygen transport in patients with sepsis with and without norepinephrine treatment. DESIGN: Prospective, clinical study. SETTING: University hospital intensive care unit. PATIENTS: A convenience sample of 15 septic shock patients treated with norepinephrine and 13 patients with severe sepsis who did not receive norepinephrine. MEASUREMENTS AND MAIN RESULTS: There were no differences between the two groups in global haemodynamics and oxygen transport. Splanchnic blood flow and oxygen delivery (splanchnic DO2 303 +/- 43 ml/min per m2) and consumption (splanchnic VO2 100 +/- 13 ml/min per m2) were much higher in the septic shock group compared with the severe sepsis group (splanchnic DO2 175 +/- 19 ml/min per m2, splanchnic VO2 61 +/- 6 ml/min per m2). Gastric mucosal pH was subnormal in both groups (septic shock 7.29 +/- 0.02, severe sepsis 7.25 +/- 0.02) with no significant difference. No significant differences between groups were detected in lactate values. CONCLUSION: These data confirm a redistribution of blood flow to the splanchnic region in sepsis that is even more pronounced in patients with septic shock requiring norepinephrine. However, subnormal gastric mucosal pH suggested inadequate oxygenation in parts of the splanchnic region due to factors other than splanchnic hypoperfusion. Progress in this area will depend on techniques that address not only total splanchnic blood flow, but also inter-organ flow distribution, intra-organ distribution, and other microcirculatory or metabolic malfunctions.

APACHE↗
PubMed1996

[The effect of prophylactically administered n-acetylcysteine on clinical indicators for tissue oxygenation during hyperoxic ventilation in cardiac risk patients].

UNLABELLED: Hyperoxic ventilation, used to prevent hypoxia during potential periods of hypoventilation, has been reported to paradoxically decrease whole-body oxygen consumption (VO2). Reduction in nutritive blood flow due to oxygen radical production is one possible mechanism. We investigated whether pretreatment with the sulfhydryl group donor and O2 radical scavenger N-acetylcysteine (NAC) would preserve VO2 and other clinical indicators of tissue oxygenation in cardiac risk patients. METHODS: Thirty patients, requiring hemodynamic monitoring (radial and pulmonary artery catheters) because of cardiac risk factors, were included in this randomized investigation. All patients exhibited stable clinical conditions (hemodynamics, body temperature, hemoglobin, F1O2 < 0.5). Cardiac output was determined by thermodilution and VO2 by cardiovascular Fick. After baseline measurements, patients randomly received either 150 mg kg-1 NAC (n = 15) or placebo (n = 15) in 250 ml 5% dextrose i.v. over a period of 30 min. Measurements were repeated 30 min after starting NAC or placebo infusion, 30 min after starting hyperoxia (F1O2 = 1.0), and 30 min after resetting the original F1O2. RESULTS: There were no significant differences between groups in any of the measurements before treatment and after the return to baseline F1O2 at the end of the study, respectively. NAC, but not placebo infusion, caused a slight but not significant increase in cardiac index (CI), left ventricular stroke work index (LVSWI) and a decrease in systemic vascular resistance. Significant differences between groups during hyperoxia were: VO2 (NAC: 108 +/- 38 ml min-1m-2 vs placebo: 79 +/- 22 ml min-1m-2; P < or = 0.05), CI (NAC: 4.6 +/- 1.0 vs placebo: 3.7 +/- 1.11 min-1m-2; P < or = 0.05) and LVSWI (NAC: 47 +/- 12 vs placebo: 38 +/- 9; P < or = 0.05). The mean decrease of VO2 was 22% in the NAC group vs 47% in the placebo group (P < or = 0.05) and the mean difference between groups in venoarterial carbon dioxide gradient (PvaCO2) was 14% (P < or = 0.05). ST segment depression ( > 0.2 mV) was significantly less marked in the NAC group (NAC: -0.02 +/- 0.17 vs placebo: -0.23 +/- 0.15; P < or = 0.05). CONCLUSIONS: NAC helped preserve VO2, oxygen delivery, CI, LVSWI and PvaCO2 during brief hyperoxia in cardiac risk patients. Clinical signs of myocardial ischemia did not occur such as ST-depression if patients were prophylactically treated with NAC. This suggests that pretreatment with NAC could be considered to attenuate impaired tissue oxygenation and to preserve myocardial performance better in cardiac risk patients during hyperoxia.

Acetylcysteine↗
PubMed1996

Dopexamine hydrochloride in septic shock.

OBJECTIVE: To test whether dopexamine hydrochloride, by its beta 2-adrenoreceptor and dopaminergic 1 (DA1) and dopaminergic 2 (DA2) agonistic properties, can improve oxygen consumption (VO2) in hyperdynamic patients with septic shock. DESIGN: Prospective, single-cohort study. SETTING: ICU, university hospital. PATIENTS: Twenty-nine postoperative, hemodynamically stabilized, hyperdynamic patients with septic shock. INTERVENTIONS: Short-term application (30 min) of dopexamine hydrochloride at a dose of 2 microgram/kg/min. MEASUREMENTS: Complete hemodynamic profile with O2 transport-related variables at baseline, 30 min after starting the dopexamine infusion, and 30 min after stopping the infusion. MAIN RESULTS: The dopexamine infusion resulted in significant increases in cardiac index (17%) (p<0.001) and O2 delivery (DO2) (16%) (p<0.001). VO2 increased slightly but significantly about 4% (p<0.001) by respiratory gas exchange measurements and 9% (p<0.001) by cardiovascular Fick calculations. The O2 extraction ratio decreased about 8% (0.001). CONCLUSIONS: The addition of dopexamine hydrochloride at a dose of 2 microgram/kg/min resulted in significant increases of DO2 and to a lesser extent VO2. Much of the global DO2 increase was not utilized, because O2 extraction ratio decreased. Direct calorigenic effects of dopexamine and an increase in myocardial VO2 likely account for a large portion of the increase in global VO2. Whether any of the VO2 increase reflects improvement in regions of jeopardized tissue oxygenation remains to be clarified before the definite value of this drug in septic shock can be established.

APACHE↗
PubMed1995

Comparison of dopamine to dobutamine and norepinephrine for oxygen delivery and uptake in septic shock.

OBJECTIVES: To test whether dopamine infusion improves oxygen delivery (Do2) and oxygen uptake (VO2) in hyperdynamic septic shock patients stabilized by adequate volume and dobutamine alone, or by the combination of dobutamine and norepinephrine. DESIGN: Prospective clinical trial of two patient groups. Group 1 (n = 15) was stabilized with dobutamine, and group 2 (n = 10) was stabilized with dobutamine and norepinephrine. SETTING: Intensive care unit in a university hospital. PATIENTS: Twenty-five postoperative, hyperdynamic septic shock patients. INTERVENTIONS: The stabilizing catecholamine infusion was replaced in a stepwise manner by dopamine to achieve a similar mean arterial pressure (dopamine doses: group 1, mean 22 +/- 15 micrograms/kg/min [range 6 to 52]; and group 2, mean 57 +/- 41 micrograms/kg/min [range 15 to 130]). MEASUREMENTS AND MAIN RESULTS: A complete hemodynamic profile was performed with oxygen transport-related variables at baseline, after replacement by dopamine, and after resetting to the original catecholamine infusion. The change to dopamine resulted in increases in cardiac index (group 1: 20% [p < .01]; group 2: 33% [p < .01]), and DO2 (group 1: 19% [p < .01]; group 2: 27% [p < .01]). However, VO2, whether directly measured from the respiratory gases or calculated by the cardiovascular Fick principle, did not change in both groups with dopamine, while the oxygen extraction ratio decreased significantly in both groups with dopamine. Heart rate, pulmonary artery occlusion pressure, and pulmonary shunt fraction all increased with dopamine. PaO2 decreased, but oxygen saturation remained stable in both groups with dopamine. CONCLUSIONS: Short-term dopamine infusion in hyperdynamic septic shock patients, despite producing higher global DO2, was not superior to dobutamine or the combination of dobutamine and norepinephrine infusion.

Adult↗
PubMed1995

Effects of catecholamines on regional perfusion and oxygenation in critically ill patients.

Multiple organ failure is the major cause of death in patients with sepsis. Bacterial translocation from the gut is considered to induce and maintain sepsis. Therefore, the splanchnic region plays an important role in the pathogenesis and treatment of sepsis. There is evidence for a very high risk of imbalance between oxygen delivery and oxygen consumption especially in the splanchnic region. Consequently, there is a crucial interest whether it is possible to influence the splanchnic perfusion by specific catecholamines. Unfortunately, only a few, conflicting studies have looked at the effects of the various catecholamines on regional blood flow. Therefore, a clear recommendation for a specific catecholamine regimen in septic shock is impossible. Furthermore, it is unknown whether the choice of a specific catecholamine in the treatment of septic shock affects the patient's outcome. In most patients, the use of vasopressors is indispensable because adequate haemodynamic perfusion pressure is not achieved with fluid therapy alone. The negative effects of vasopressors on splanchnic perfusion are known from studies carried out under non septic conditions. Norepinephrine and dopamine in doses of 10 micrograms/kg/min in septic animals are without negative effects on splanchnic perfusion. Preliminary results show Preliminary results show a decrease in splanchnic oxygenation in patients with septic shock treated with epinephrine. Catecholamines with beta mimetic effects are often used to increase DO2. The question as to whether dobutamine or dopamine should be used first in treatment of septic shock cannot be answered yet. Whether treatment with low dose dopamine or dopexamine actually improves renal function and splanchnic oxygenation is the purpose of ongoing studies.

Adrenergic beta-Agonists↗
PubMed1995

N-acetylcysteine preserves oxygen consumption and gastric mucosal pH during hyperoxic ventilation.

Hyperoxic ventilation, used to prevent hypoxemia during potential periods of hypoventilation, has been reported to paradoxically decrease whole body oxygen consumption (VO2). Reduction in nutritive blood flow due to oxygen radical production is one possible mechanism. We investigated whether pretreatment with the sulfhydryl group donor and O2 radical scavenger N-acetylcysteine (NAC) would preserve whole body VO2 and prevent deterioration of oxygenation in gastric mucosal tissue during hyperoxia. Thirty-eight patients, requiring hemodynamic monitoring (radial and pulmonary artery catheters) due to sepsis syndrome, were included in this randomized experiment. All patients exhibited stable clinical conditions (hemodynamics, body temperature, hemoglobin, FIO2 < 0.5). A gastric tonometer was placed to measure the gastric intramucosal pH (pHi), which indirectly assesses nutritive blood flow to the mucosa. Cardiac output was determined by thermodilution and VO2 by cardiovascular Fick. After baseline measurements, patients randomly received either 150 mg.kg-1 NAC (n = 19) or placebo (n = 19) in 250 ml 5% dextrose intravenously over a period of 15 min. Measurements were repeated 30 min after starting NAC or placebo infusion, 30 min after starting hyperoxia (FIO2 = 1.0), and 60 min after resetting the original FIO2. There were no significant differences between groups in any of the measurements before treatment and after the return to baseline FIO2 at the end of the study. NAC, but not placebo infusion, caused a slight but significant increase in cardiac output and decrease in systemic vascular resistance.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcysteine↗
PubMed1994

The relationship between mixed venous and hepatic venous O2 saturation in patients with septic shock.

It was the purpose of this study to measure the relationship between hepatic venous O2 saturation (ShvO2) and mixed venous O2 saturation (SvO2) in septic patients (n = 21) following treatment with various catecholamines (epinephrine, norepinephrine, dopamine, dopexamine). At baseline mean SvO2 was 74 +/- 5% while mean ShvO2 was 59 +/- 12%. Alpha-mimetic substances such as epinephrine and norepinephrine reduced ShvO2 and increased the difference between SvO2 and ShvO2.Beta2-mimetic and dopaminergic substances (dopexamine, dopamine) did not change the difference between SvO2 and ShvO2. These results show that SvO2 does not necessarily reflect all changes of ShvO2. Monitoring ShvO2 may be helpful in managing septic shock by adding information on adequacy of O2 supply/consumption ratio in the crucial splanchnic region.

Dobutamine↗
PubMed1994

The relevance of measuring O2 supply and O2 consumption for assessment of regional tissue oxygenation.

Septic shock and ARDS are associated with disturbed tissue oxygenation. It has been suggested to increase O2 supply (DO2) above the normal level (> 600 ml/min/m2) to compensate for the tissue hypoxia. The lack of a rise in O2 consumption (VO2) after increases of DO2 has been presumed to indicate adequate tissue oxygenation (negative O2 flux test). We were interested in whether a negative O2 flux test precludes an improvement of regional tissue oxygenation. The pH value of the gastric mucosa (pHi) is considered to be a sensitive marker for hypoxia in the splanchnic region. We measured pHi as well as DO2 and VO2 in 10 patients with hyperdynamic septic shock to assess the effect of volume substitution on tissue oxygenation. The initial therapeutic approach (volume substitution and catecholamines) led to a DO2 of 717 +/- 187 ml/min/m2. However, all patients had pHi values < 7.35 indicating regional tissue hypoxia. An additional increase of DO2 by colloidal volume substitution caused a significant rise of pHi from 7.20 +/- 0.05 to 7.25 +/- 0.05 but did not change VO2. We conclude that a negative O2 flux test does not rule out regional tissue hypoxia, and second, an increase in DO2 may improve tissue oxygenation without measurable changes in VO2. Furthermore, adequate volume substitution is an important step in the treatment of septic shock to increase total body blood flow and more specifically regional blood flow.

Biological Transport, Active↗