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Biomedical subjects

E Berendes

Publications and source records attributed to E Berendes.

27 records · Page 2Linked to original sources
PubMed1997

Secretion of brain natriuretic peptide in patients with aneurysmal subarachnoid haemorrhage.

BACKGROUND: Subarachnoid haemorrhage is commonly associated with natriuresis and hyponatraemia. One possible explanation for these features is a defect in the central regulation of renal sodium reabsorption with increased secretion of a natriuretic factor. We investigated whether excess sodium secretion in patients with subarachnoid haemorrhage is related to increased secretion of natriuretic peptides or to the presence of digoxin-like immunoreactive substances. METHODS: We measured the plasma concentrations of digoxin-like immunoreactive substances (by a fluorescence polarisation immunoassay) and natriuretic peptides, aldosterone, renin, and antidiuretic hormone (by radioimmunoassay) in ten patients with aneurysmal subarachnoid haemorrhage, ten patients undergoing elective craniotomy for cerebral tumours, and 40 healthy controls of similar age and sex distribution. Samples were collected before surgery, 1 h, 4 h, and 12 h after surgery, then daily until 7 days postoperatively in the two groups of patients. FINDINGS: All patients with subarachnoid haemorrhage, but none of the tumour patients, showed increased urine output and urinary excretion of sodium (p = 0.018 for comparison of means of curves to 7 days). The patients with subarachnoid haemorrhage had much higher plasma concentrations of brain natriuretic peptide (BNP) than controls, on admission (mean 15.1 [SE 3.8] vs 1.6 [1.0] pmol/L, p < 0.001) and throughout the study period, accompanied by lower than normal aldosterone concentrations and normal plasma concentrations of atrial and C-type natriuretic peptides (ANP, CNP). The patients with tumours had similar plasma concentrations of ANP, BNP, and CNP to the controls. We did not detect digoxin-like immunoreactive substances in either group of patients. INTERPRETATION: Salt-wasting of central origin may induce hyponatraemia in patients with aneurysmal subarachnoid haemorrhage, possibly as a result of increased secretion of BNP with subsequent suppression of aldosterone synthesis.

Brain Neoplasms↗
PubMed1997

Influence of enoximone on systemic and splanchnic oxygen utilization and endotoxin release following cardiopulmonary bypass.

OBJECTIVE: We investigated whether the administration of enoximone during and after cardiopulmonary bypass (CPB) improves splanchnic oxygen utilization and thereby gut mucosal integrity in humans by its vasodilating and inotropic properties. SETTING: Surgical intensive care unit (ICU) in a university hospital. DESIGN/PATIENTS: 21 patients (ASA III classification) scheduled for elective coronary artery bypass grafting were enrolled in the study. After induction of general anesthesia, patients were randomly assigned to received a bolus of 0.2 mg/kg enoximone, followed by 5 microg/kg per min (enoximone group), or followed by an equal volume of saline (NaCl group) during and 24 h after the surgical procedure. The following parameters were evaluated at different time intervals: systemic and pulmonary hemodynamics, blood gas analysis of arterial, mixed venous, and liver venous blood, venous and liver venous lactate level, venous and liver venous endotoxin level and intramucosal partial pressure of carbon dioxide for calculation of intramucosal pH (pHi). RESULTS: Enoximone raised cardiac output and oxygen delivery to higher levels than those observed in the NaCl group. In both groups, gastric pHi fell continuously during the study period. The values were significantly decreased 12 h following admission to the ICU. Endotoxin was not detectable at baseline. Both groups showed increased endotoxin levels, with the highest values during the first 6 h postoperatively. The hepatic venous endotoxin level was almost doubled in the NaCl group in comparison to the enoximone group. Endotoxin levels differed in the two groups 6 and 12 h after admission to the ICU. CONCLUSIONS: Improvement of oxygen delivery by enoximone did not prevent gastric mucosal acidosis following CPB. However, since the increase in endotoxin levels in liver venous blood was diminished by using enoximone, the drug seems to have a beneficial effect on tissue damage and barrier function of the gut.

Aged↗
PubMed1997

Effects of dopexamine on creatinine clearance, systemic inflammation, and splanchnic oxygenation in patients undergoing coronary artery bypass grafting.

Impairment of splanchnic and peripheral tissue perfusion during cardiopulmonary bypass (CPB) may be responsible for endotoxin-mediated systemic inflammation and acute phase responses. We examined the effects of dopexamine on hemodynamic parameters, creatinine clearance, systemic and splanchnic oxygenation, gastric mucosal pH (pHi), and mixed and hepatic venous plasma levels of endotoxin, interleukin-6 (IL-6), serum amyloid A (SAA), and C-reactive protein (CRP) in 44 patients scheduled for coronary artery bypass grafting. Patients were randomized to receive continuous infusions of 0.5, 1.0, or 2 micrograms.kg-1.min-1 dopexamine (n = 10 per group) or placebo (n = 14) prior to surgery, intraoperatively, and postoperatively. Dopexamine infusion increased systemic oxygen delivery (P < or = 0.01). Hepatic venous oxygen saturation did not change, and pHi decreased during and after CPB in all patients (P < or = 0.01). Postoperative increases in IL-6 were smallest in patients who received 2.0 micrograms.kg-1.min-1 dopexamine (P < or = 0.02). SAA and CRP increases during the postoperative period were less pronounced with dopexamine throughout the study. Creatinine clearance was elevated in all dopexamine groups (P < or = 0.025). This elevation was higher with lower dopexamine doses (P < or = 0.025). We conclude that dopexamine improves creatinine clearance and reduces systemic inflammation without affecting splanchnic oxygenation.

Acute-Phase Reaction↗
PubMed1997

Increased plasma concentrations of serum amyloid A: an indicator of the acute-phase response after cardiopulmonary bypass.

OBJECTIVES: To assess the expression of mixed and hepatic venous serum amyloid A (SAA) concentrations and its relationship to plasma concentrations of C-reactive protein, interleukin-6 (IL-6), and endotoxin during and after cardiopulmonary bypass (CPB). DESIGN: Prospective, consecutive sample with repeated measurements. SETTING: Surgical intensive care unit (ICU) in a university hospital. PATIENTS: Twenty patients who underwent elective coronary bypass grafting. INTERVENTIONS: A radial artery catheter, pulmonary artery catheter, and right hepatic vein catheter were inserted. Blood samples were collected to determine the different mediators, lactate concentrations, and oxygen saturations. MEASUREMENTS AND MAIN RESULTS: After induction of anesthesia, baseline values were obtained and the following parameters were determined 20 mins after onset of CPB, 20 mins after termination of CPB, at admission to the ICU, and 6, 8, 12, and 24 hrs later: hemodynamics, body core temperature, hepatic venous oxygen saturation, and mixed and hepatic venous lactate, endotoxin, interleukin (IL)-6, C-reactive protein (CRP), and SAA concentrations. Endotoxin and IL-6 plasma concentrations increased during CPB, peaked 6 hrs after admission to the ICU (endotoxin: 23.1 +/- 6.2 pg/mL; IL-6: 646 +/- 104 pg/mL), and decreased thereafter; SAA and CRP concentrations began to increase after 6 and 8 hrs, respectively, with the highest concentrations reached 24 hrs postoperatively (CRP: 14 +/- 3.6 mg/L; SAA: 668 +/- 114 micrograms/mL). Lactate concentrations began to increase 20 mins after CPB, and continued to increase until 12 hrs postoperatively. There were no significant differences between mixed and hepatic venous values of endotoxin, IL-6, CRP, SAA, and lactate (p < .05). Body core temperature, which was < 37.5 degrees C before surgery for all patients, increased 6 hrs after admission to the ICU and peaked 12 hrs postoperatively (38.3 +/- 1.1 degrees C). Hepatic venous oxygen saturation did not change. Correlations were obtained between IL-6 values and heart rate (r2 = .20; p < .005), and endotoxin concentrations and systemic vascular resistance (r2 = .18; p < .001). Body core temperature correlated significantly closer with SAA (r2 = .52; p < .0001) values than with IL-6 (r2 = .27; p < .0001) or CRP (r2 = .16; p < .001) values (p < .05). CONCLUSIONS: SAA is an additional and sensitive marker of the acute-phase response following CPB; the increase in SAA concentrations parallels the temporary increase in body core temperature and is preceded by endotoxemia and IL-6 secretion.

Acute-Phase Reaction↗
PubMed1996

[Anxiolysis, sedation, and stress reduction following oral premedication with midazolam in adults. A comparison with dipotassium clorazepate and placebo].

Benzodiazepines are the most commonly used anxiolytic agents. Among the benzodiazepines, midazolam has the advantage of a short elimination half-life, which is especially useful in outpatient surgery. However, in contrast to other commonly prescribed benzodiazepines, such as chlorazepate dipotassium, oral premedication with midazolam has not been thoroughly investigated. Therefore, the present study was performed to compare anxiolysis, sedation and stress reduction with midazolam and clorazepate dipotassium in adults. METHODS. After IRB approval and informed consent had been obtained, 85 patients scheduled for breast biopsy were studied. The patients were chosen at random to receive either 7.5 mg midazolam (n = 29), 20 mg clorazepate dipotassium (n = 28) or placebo (n = 28) preoperatively. Before premedication, immediately prior to surgery and postoperatively in the recovery room, the following parameters were determined with visual analogue scales (VAS): "asthenia," "depression," oral salivation, muscle tension, motoric restlessness and sweating of the palms. In addition, anxiety (STAI-G-X-1, Spielberger), heart rate and arterial blood pressure were measured. Before patients underwent surgery, the degree of sedation was evaluated by the anaesthesiologist. RESULTS. Clorazepate dipotassium and midazolam both caused a reduction in anxiety as compared with the placebo (P < 0.05). Only clorazepate dipotassium reduced anxiety postoperatively (P < 0.05). Neither midazolam nor clorazepate dipotassium caused a reduction in "asthenia" and "depression." Midazolam was more effective in preventing increased blood pressure than clorazepate dipotassium and the placebo (P < 0.05). Furthermore, after premedication with midazolam, salivation, muscle tension, motoric restlessness and sweating of the palms remained stable, in contrast to the results after premedication using clorazepate dipotassium or placebo (P < 0.05). CONCLUSIONS. The anxiolytic effects of 7.5 mg midazolam and 20 mg clorazepate dipotassium were similar after oral application. However, the anxiolytic effect of midazolam is shorter-lived than that of clorazepate dipotassium. In contrast to clorazepate dipotassium, midazolam produced no increase in arterial blood pressure and stabilized oral salivation, production in the palms, muscle tension and motoric restlessness.

Adult↗
PubMed1996

Effects of enflurane and isoflurane on splanchnic oxygenation in humans.

STUDY OBJECTIVES: To determine the effects of enflurane and isoflurane on hepatic venous oxygen saturation (ShvO2) and splanchnic oxygen (O2) extraction. To measure hemodynamic parameters and ShvO2, mixed venous, and arterial lactate concentrations during enflurane and isoflurane anesthesia. DESIGN: Randomized, prospective study. SETTING: University hospital. PATIENTS: 20 ASA physical status I, II, and III adults, who underwent major abdominal surgery requiring mechanical ventilation a few hours postoperatively. INTERVENTIONS: After placement of catheters in the pulmonary artery, radial artery, peripheral and right hepatic vein, one hour postoperatively either enflurane or isoflurane was applied at different minimum alveolar concentration (MAC) of 0.5, 1.0, and 1.5 in a randomized order. MEASUREMENTS AND MAIN RESULTS: Before and 10 minutes after administration of each desired end-expiratory anesthetic concentration, the following parameters were determined: hemodynamic parameters, arterial (SaO2), mixed venous (SvO2), and hepatic venous oxygen saturations, systemic and splanchnic O2 extraction, arterial, mixed venous, and hepatic venous lactate concentrations. Cardiac output (CO) and mean arterial pressure (MAP) decreased in a dose dependent manner. SaO2, SvO2, and systemic O2 extraction remained unchanged with enflurane and isoflurane anesthesia. In the enflurane group, but not in the isoflurane group, ShvO2 decreased with increasing inhalational concentrations. This decrease in ShvO2 reflected an increase in splanchnic O2 extraction with enflurane; in contrast to isoflurane. CONCLUSIONS: Enflurane causes a decrease in ShvO2, which indicates an impairment of splanchnic perfusion corresponding to the reduction in CO and MAP in a dose-dependent manner. Isoflurane maintains splanchnic perfusion in contrast to enflurane.

Aged↗
PubMed1996

Effects of positive end-expiratory pressure ventilation on splanchnic oxygenation in humans.

OBJECTIVES: To examine the influence of positive end-expiratory pressure (PEEP) ventilation on splanchnic oxygenation and lactate production in humans without pulmonary disorders. DESIGN: Prospective study. SETTING: Single-institutional surgical intensive care unit in a university hospital. PARTICIPANTS: Twenty patients who underwent major abdominal surgery. INTERVENTIONS: Radial artery, pulmonary artery, and right hepatic vein catheters. Blood samples were collected to determine lactate concentrations and oxygen saturations. MEASUREMENTS AND MAIN RESULTS: Six hours postoperatively PEEP levels (5, 10, and 15 cmH2O) were applied in a randomized order, and the following parameters were determined before and at the end of each PEEP level: cardiac output (CO); mean arterial pressure (MAP); arterial (SaO2), mixed venous (SvO2) and hepatic venous oxygen saturation (ShvO2); systemic (C[a-v]O2) and splanchnic (C[a-hv]O2) arterial venous oxygen content difference; and arterial, mixed venous, and hepatic venous lactate concentration. CO and MAP were reduced at PEEP 10 and 15 cmH2O, accompanied by a decrease in SvO2 but unchanged SaO2. A decrease in ShvO2 was seen at PEEP 15 cmH2O. C(a-v)O2 and C(a-hv)O2 were increased at PEEP 15 cmH2O. However, at PEEP 15 cmH2O, the percent increment in C(a-hv)O2 was greater than the increment in C(a-v)O2. Lactate concentrations remained unchanged. CONCLUSIONS: Ventilation with PEEP causes reductions in CO and MAP, resulting in a comparable impairment of systemic and splanchnic oxygen. The absence of changes in lactate concentrations indicates that a critical reduction in systemic and splanchnic oxygenation is unlikely during ventilation with low or high PEEP levels.

Adult↗
PubMed1992

[Massive natriuresis and polyuria after triple craniocervical subarachnoid hemorrhage: cerebral salt wasting syndrome?].

A thirty-year-old male patient suffered subarachnoidal haemorrhage from an angioma positioned in the cranio-cervical transition. After rebleeding twice the patient developed a hydrocephalus internus malresorptivus and excessive natriuresis and polyuria, accompanied by depressed renin activity and extremely low aldosterone plasma levels. Neither fluid restriction and sodium substitution, nor administration of hydro-chlorothiazide/indomethacin affected natriuresis and polyuria. It was only after treatment with fludrocortisone-acetate/hydrocortisone that hyponatraemia and polyuria were resolved. At the same time a ventriculo-peritoneal shunt was applied. Differential diagnosis excluded the syndromes of inadequate antidiuretic hormone secretion, renal and cerebral diabetes insipidus, osmotic receptor hypofunction, chronic renal dysfunction and tubular necrosis. Natriuresis and polyuria developed under dexamethasone therapy. Since patient history, physical examination and laboratory criteria could not explain the electrolyte and fluid imbalance, this might be attributed to the hydrocephalus. Similar disturbances have been reported from other patients with intracranial disorders. Mechanical pressure exercised on the hypothalamus might cause the disturbance of fluid and sodium balance. Assuming a cerebral salt wasting syndrome, a putative natriuretic factor coming from the brain or an imbalance in the cerebral renin-angiotensin-system, as described in rats and dogs, must be discussed.

Adult↗