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H Böhrer

Publications and source records attributed to H Böhrer.

At least 73 records · Page 4Linked to original sources
PubMed1996

Platelet factor 4 release in patients undergoing cardiopulmonary resuscitation--can reperfusion be impaired by platelet activation?

BACKGROUND: Reperfusion following cardiac arrest is associated with a marked activation of blood coagulation. This seems to be associated with microcirculatory reperfusion disorders. The present study was designed to investigate the possible involvement of platelets in reperfusion injury following cardiac arrest. Plasma levels of platelet factor 4 (PF 4) were used as an indicator for in vivo platelet activation because PF 4 is known to be released from platelets during aggregation. METHODS: Plasma PF 4 levels (normal range: < 5IU/mL) were measured in 18 patients at predetermined time points during cardiopulmonary resuscitation (CPR). In the case of restoration of spontaneous circulation, additional blood samples were analyzed until seven days after stabilization. The PF 4 levels of four sex-matched volunteers were used as controls. RESULTS: The median of the maximum individual PF 4 levels measured during CPR was 27.5 IU/mL (range 1.2 to 90 IU/ liter; P < 0.01 versus controls). Compared with PF4 levels in control volunteers (median: 0.35 IU/mL; range 0.2 to 0.6 IU/ liter), PF 4 levels were significantly elevated in patients during CPR and in the early phase until 24 hours after restoration of spontaneous circulation (P < 0.05). CONCLUSION: A marked increase in PF 4 levels was observed during CPR and in the early phase after cardiac arrest in man. This increase in PF 4 levels has to be viewed as an indicator of platelet activation, which may play a role in the etiology of reperfusion injury and microcirculatory reperfusion disorders occurring after cardiac arrest.

Aged↗
PubMed1995

Mechanism of the tumor necrosis factor alpha-mediated induction of endothelial tissue factor.

This study examines the regulation of the human tissue factor (TF) promotor in vitro and in vivo. Transient transfections were performed in bovine aortic endothelial cells to investigate the role of two fundamentally different AP-1 sites and a closely located NF-kappa B site in the human TF promoter. The NF-kappa B site is functionally active, since overexpression of NF-kappa B(p65) resulted in induction of TF mRNA and activity. Promoter analysis showed that NF-kappa B induction was dependent on the integrity of the region from base pair -188 to -181. Over-expression of Jun/Fos resulted in TF induction of transcription and protein/activity. Functional studies revealed that the proximal AP-1 site, but not the distal, was inducible by Jun/Fos heterodimers. The distal AP-1 site, which has a G-->A switch at position 4, was inductible by Jun homodimers. Electrophoretic mobility shift assays, using extracts of tumor necrosis factor alpha (TNF alpha)-stimulated bovine aortic endothelial cells, demonstrated TNF alpha-inducible binding to the proximal AP-1 site, comprising JunD/Fos heterodimers. At the distal AP-1 site, only minor induction of binding activity, characterized as proteins of the Jun and ATF family, was observed. Consistently, this site only marginally participates in TNF alpha induction. Functional studies with TF promotor plasmids confirmed that deletion of the proximal AP-1 or the NF-kappa B site decreased TNF alpha-mediated TF induction to a higher extend than loss of the distal AP-1 site. However, integrity of both AP-1 sites and the NF-kappa B site was required for optimal TNF alpha stimulation. The relevance of these in vitro data was confirmed in vivo in a mouse tumor model. Expression plasmids for a dominant negative Jun mutant or I-kappa B were packaged in liposomes. When either mutated Jun or I-kappa B were injected intravenously 48 h before TNF alpha, a reduction in TNF alpha-mediated TF expression in the tumor endothelial cells was observed. Simultaneously, fibrin/fibrinogen deposition decreased and free blood flow could be restored. Thus, TNF alpha-induced up-regulation of endothelial cell TF depends on a concerted action of members of the bZIP and NF-kappa B family.

Animals↗
PubMed1995

Activation of blood coagulation after cardiac arrest is not balanced adequately by activation of endogenous fibrinolysis.

BACKGROUND: Animal studies have demonstrated that hemostatic disorders occurring after cardiac arrest affect outcome. We investigated hemostatic changes during and after cardiopulmonary resuscitation (CPR) in humans. METHODS AND RESULTS: The prospective study included 23 patients (29 to 86 years) who underwent out-of-hospital CPR for nontraumatic causes. Blood samples were drawn immediately and 15 and 30 minutes after initiation of CPR. In the case of restoration of spontaneous circulation (ROSC; n = 7), additional blood samples were taken immediately, 30 minutes, and 2, 8, 24, 48, and 72 hours after ROSC. A marked activation of blood coagulation was found in all patients. The specific markers of activated blood coagulation and fibrin formation, thrombin-antithrombin complex (TAT; median during CPR, 260 micrograms/L; median after ROSC, 57 micrograms/L; normal range, 1.0 to 4.1 micrograms/L), and fibrin monomers (FM; median during CPR, 34.3 micrograms/mL; median after ROSC, 65.4 micrograms/mL; normal range, 0 to 3.6 micrograms/mL) were markedly increased during and in the early phase after CPR. When patients survived for 48 hours, TAT and FM values returned to the normal range. In most patients, the plasma levels of D-dimer, an indicator of endogenous fibrinolytic activity, were not markedly increased during CPR (median, < 0.25 microgram/mL; normal range, < 0.25 microgram/mL) but increased moderately after ROSC (median, 0.56 microgram/mL). Levels of plasminogen activator inhibitor type 1 (normal range, 0.3 to 3.5 U/mL), a marker for endogenous inhibition of fibrinolytic activity, were moderately increased in most patients (median during CPR, 4.22 U/mL; median after ROSC, 8.08 U/mL). CONCLUSIONS: Our data clearly demonstrate that there is a marked activation of blood coagulation and fibrin formation after prolonged cardiac arrest and CPR in humans that is not balanced adequately by concomitant activation of endogenous fibrinolysis. These changes may contribute to reperfusion disorders, such as the cerebral "no-reflow" phenomenon, by inducing fibrin deposition and formation of microthrombi.

Adult↗
PubMed1995

Recovery characteristics following anaesthesia with sevoflurane or propofol in adults undergoing out-patient surgery.

The aim of the study was to compare recovery characteristics in adult patients following general anaesthesia either with the new investigational volatile agent sevoflurane or with propofol. Accordingly, two groups of 25 adults undergoing outpatient surgery were entered into a prospective, randomised study. Patients who received sevoflurane were extubated at an earlier stage than those receiving propofol (6.6 vs. 9.8 min), and the times to eye opening (7.2 vs. 12.6 min) and hand squeezing (8.2 vs 13.8 min) were also shorter. As measured by the digit-symbol substitution test, patients regained the pre-operative level of cognitive function significantly earlier after sevoflurane anaesthesia. Modified Aldrete scores were also higher in this group within the first hour after anaesthesia than in the propofol group. Sevoflurane appears to be a useful alternative to propofol in outpatient anaesthesia.

Adult↗
PubMed1995

[Autologous blood donation in obstetrics].

OBJECTIVE: To demonstrate the safety of autologous blood donation in an obstetric practice. METHODS: A total of 2350 pregnant patients were screened for an increased risk of peripartum bleeding. Excluding patients with contraindications, a total of 71 women participated in this autologous blood donation program. Blood was donated in the 35th and 37th weeks of pregnancy. RESULTS: No problems occurred in the course of blood donation. All newborns were found to be healthy; 41 of the 71 patients received peripartum autologous blood transfusions. Homologous blood was not given to any of the patients. CONCLUSION: Our experience demonstrates that autologous blood donation is a safe practice in the setting of obstetrics, when the indications and contraindications are considered. Further studies in larger patient populations are necessary to expand or restrict the indications for autologous transfusion in obstetrics.

Adult↗
PubMed1995

Continuous versus intermittent cardiac output measurement in cardiac surgical patients undergoing hypothermic cardiopulmonary bypass.

OBJECTIVE: Continuous thermodilution cardiac output (CCO) measurement was clinically evaluated in patients who underwent coronary revascularization using hypothermic low-flow, low-pressure cardiopulmonary bypass (CPB). DESIGN: Prospective study. SETTING: University hospital setting. PARTICIPANTS: 30 cardiac surgical patients. INTERVENTIONS: CCO was correlated to standard bolus thermodilution cardiac output (ICO) obtained at end-expiration. MEASUREMENTS AND MAIN RESULTS: Measurements were taken at selected time points (n = 18) before anesthesia induction, before CPB, and 5 minutes to 12 hours after CPB. A total of 540 data pairs were thus obtained. ICO ranged from 1.9 to 9.9 L/min, CCO from 1.5 to 9.9 L/min. Correlation between ICO and CCO was highly significant (r = 0.872; p < 0.01), accompanied by an excellent accuracy (bias -0.0213 L) and precision (0.59 L) before CPB and more than 45 minutes after CPB. However, during the first 45 minutes after CPB, there was no correlation (r = 0.273) between ICO and CCO, and ICO tended to be relatively high, whereas CCO measurements showed relatively low values. During the first 45 minutes after hypothermic CPB, but not during the ensuing time period, central blood temperature decreased, which may be interpreted as a lack of thermal equilibration between central and peripheral compartments. It is hypothesized that thermal instability in combination with increased respiratory variations in pulmonary artery blood temperature caused inhomogenous rewarming of different body sites and might be the main reason for the lack of correlation between ICO and CCO. CONCLUSIONS: Despite an excellent correlation, accuracy, and precision between CCO and ICO before CPB and more than 45 minutes after hypothermic CPB, a lack of correlation in the early phase after CPB has been found. Further investigation is needed to elucidate the underlying cause of these findings and to clarify whether ICO or CCO or both fail to represent the real cardiac output up to 45 minutes after weaning from hypothermic CPB.

Adult↗
PubMed1995

[Current status of ambulatory pediatric anesthesia].

Anaesthesia in paediatric outpatients represents a multi-facetted challenge for the anaesthesiologist. Certain steps have to be taken to allow preoperative examination of the patient on an outpatient basis. Preoperative screening should identify patients whom it is preferable to treat as inpatients. During the preoperative visit, the patient must be prepared for anaesthesia, and the importance of preoperative fasting must be stressed. The anaesthetic technique used has to take into consideration the fact that the patient must be awake and alert in the early postoperative period. Adequate pain treatment is essential postoperatively. Prophylactic administration of antiemetic agents must be considered for special operations. Patients should also be discharged according to standardised guidelines. In this way, the risks involved in anaesthesia and surgery should not be higher for outpatients than they are for inpatients.

Ambulatory Surgical Procedures↗
PubMed1995

[Behavior of intraocular pressure in anesthesia with isoflurane in comparison with propofol/alfentanil].

AIM: To investigate the influence of isoflurane anaesthesia versus total intravenous anaesthesia with propofol/alfentanil on intraocular pressure (IOP). METHODS: 40 patients undergoing ophthalmic surgery were randomly allocated to two study groups. In group 1 (n = 20), anaesthesia was induced with thiopentone 4 mg/kg and alfentanil 15 micrograms/kg. Maintenance of anaesthesia was achieved with isoflurane 0.5-0.8 Vol.% and 70% nitrous oxide in oxygen. Patients in group 2 (n = 20) received propofol 1.5 mg/kg, which was followed by a continuous infusion of 6 mg/kg/h. In addition, alfentanil 15 micrograms/kg was administered, followed by a continuous infusion of 15 micrograms/kg/h. In both groups, endotracheal intubation was facilitated by succinylcholine 1 mg/kg, and further muscle relaxation was achieved with vecuronium 0.07 mg/kg. Measurements of IOP using an applanation tonometer were taken in each patient at 10 different time points. RESULTS: In both groups, there was a significant decrease in IOP after induction of anaesthesia. No significant differences in IOP occurred between groups, with patients in group 2 showing a trend towards lower IOP values. CONCLUSION: We conclude from our results that both anaesthetic techniques can be administered if increases in IOP have to be avoided.

Aged↗
PubMed1995

[Novocaine].

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Anesthesia, Local↗
PubMed1995

[Cyclopropane].

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Anesthetics, Inhalation↗
PubMed1995

[Thrombomodulin as endothelial cell marker in heart surgery patients].

OBJECTIVE: Thrombomodulin is a high-affinity receptor for thrombin on the endothelial cell surface. The aim of our study was to investigate whether plasma thrombomodulin represents a marker of endothelial injury following cardiopulmonary bypass. METHODS: Plasma levels of thrombomodulin were quantitated in 70 plasma samples obtained from 14 adult cardiac patients undergoing hypothermic pulsatile low-flow low-pressure cardiopulmonary bypass. Blood samples were taken before cardiopulmonary bypass (T1), and 15 minutes (T2), 1 hour, 6 hours, and 20 hours after termination of bypass. Plasma thrombomodulin was quantitated with a sandwich enzyme-linked immunosorbent assay (ELISA). Statistical analysis was performed by the Friedman and Wilcoxon tests. RESULTS: Plasma thrombomodulin was significantly elevated 20 hours after discontinuation of cardiopulmonary bypass, when compared with T1 and T2. CONCLUSION: We conclude from our results that a moderate elevation of plasma thrombomodulin is seen in adult patients following hypothermic, low-flow low-pressure cardiopulmonary bypass, which may reflect endothelial injury. Circulating thrombomodulin levels are thus possibly useful for assessment of endothelial damage occurring in patients undergoing cardiopulmonary bypass.

Adult↗
PubMed1995

Testing the porphyrinogenicity of propofol in a primed rat model.

We evaluated the porphyrinogenicity of propofol in a rat model. After a pilot study had been conducted to determine an optimal dose, 48 fasting male Sprague-Dawley rats were allocated randomly to six groups. The animals in groups 1-3 received saline i.p. In groups 4-6, the animals were given allylisopropylacetamide (AIA). Twelve hours later, animals in groups 1 and 4 received saline, groups 2 and 5 were given propofol 150 mg kg-1 i.p., followed by 75 mg kg-1 3 h later, and groups 3 and 6 received phenobarbitone 50 mg kg-1 i.p. and 25 mg kg-1 i.p. The animals were anaesthetized and killed 3 h after the second drug bolus and we measured the concentration of cytochrome P450, total porphyrin content and the activity of delta-aminolaevulinic acid synthase (ALAS) in the liver. Urinary delta-aminolaevulinic acid (ALA) and porphobilinogen (PBG) concentrations were measured. Analysis of variance and the t test with Bonferroni's correction were used to compare data. The hepatic cytochrome P450 concentration in the non-primed groups varied from 28.1 to 31.1 nmol g-1; administration of AIA decreased this to 20.1-20.9 nmol g-1. Total hepatic porphyrins were between 0.78 and 1.22 nmol g-1 in the non-primed groups and between 2.71 and 3.54 nmol g-1 in the AIA-primed groups. Hepatic ALAS activity was 29.2 and 35.5 nmol h-1 g-1 in groups 1 and 2. In the primed saline group, ALAS activity was measured at 134.5 nmol h-1 g-1.(ABSTRACT TRUNCATED AT 250 WORDS)

5-Aminolevulinate Synthetase↗
PubMed1995

Lignocaine metabolite formation: an indicator for liver dysfunction and predictor of survival in surgical intensive care patients.

Formation of the lignocaine metabolite monoethyl-glycine-xylidide (MEGX) by hepatic cytochrome P450 enzymes is a new method for evaluating liver function. The purpose of this study was to compare MEGX formation with other liver function parameters in surgical intensive care unit patients. The study include 29 critically ill patients who had been admitted to the unit for more than 3 days with a median APACHE III score-predicted mortality > 30%. On day 4, lignocaine was given intravenously at a dose of 1 mg.kg-1 over 2 min and MEGX formation was measured 15 min later. Eighty-nine percent of the patients had MEGX values below 90 micrograms.l-1 indicating impaired liver function. Eleven patients died, 18 patients survived. The group of patients with fatal outcome had significantly lower MEGX values (median: 23 micrograms.l-1) than the group of survivors (median: 53 micrograms.l-1, p < 0.01). Bilirubin values were elevated in the non-survivor group (median: 2.8 mg.dl-1) compared to the survivors (median: 0.9 mg.dl-1, p < 0.05). There was no significant difference between two groups in the other liver function tests. We conclude from our results that the MEGX test can be considered an indicator for hepatic dysfunction and predictor of survival in critically ill patients.

Aged↗
PubMed1995

Early proponents of cardiac massage.

Open-chest cardiac massage in humans to treat chloroform syncope was first performed by Niehans in Berne and Langenbuch in Berlin in the late 1880s. Closed-chest cardiac massage in humans was advocated by Koenig and Maass in Göttingen in the last two decades of the 19th century. The closed technique was used in Central Europe for several decades to treat chloroform syncope.

Anesthesiology↗