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S Piepenbrock

Publications and source records attributed to S Piepenbrock.

At least 73 records · Page 4Linked to original sources
PubMed2000

Succinylcholine metabolite succinic acid alters steady state activation in muscle sodium channels.

BACKGROUND: Animal experiments revealed that succinylcholine produced masseter muscle rigidity and activated myotonic discharges despite neuromuscular blockade with a nondepolarizing blocker. These results suggest that either succinylcholine or its metabolites might interfere directly with voltage-operated ion channels of the sarcolemma. The aim of this study was to examine effects of one product of succinylcholine hydrolysis, succinic acid, on voltage-gated muscle sodium (Na+) channels. METHODS: Alpha subunits of human muscle sodium channels were heterologously expressed in HEK293 cells. Activation of Na+ currents was examined applying standard whole-cell voltage-clamp protocols in the absence (control and washout) and presence of succinic acid in different concentrations (0.05-10 mm). RESULTS: Succinic acid shifted the midpoints of steady state activation plots in the direction of more negative test potentials, indicating that channels open during smaller depolarizations in the presence of the drug. The maximum amount of the negative shift in 10 mm succinic acid was -6.3 +/- 1.7 mV; the EC50 for this effect was 0.39 mm. In addition, succinic acid (10 mm) significantly enhanced maximum currents after depolarizations with respect to a series of control experiments. CONCLUSION: Succinic acid facilitates voltage-dependent activation in muscle sodium channels in vitro. This might lead to muscle hyperexcitability in vivo.

Anti-Ulcer Agents↗
PubMed2000

[Carbon monoxide poisoning].

Carbon monoxide (CO) is a product of incomplete burning of coals and carbon compounds and is a gas without any typical taste, colour or smell. Defective radiators or gas pipes, open fireplaces, fires and explosions are sources of unintended CO production and inhalation. CO bonds with haemoglobin much more readily than oxygen does. CO toxicity causes impaired oxygen delivery and utilisation at cellular level. It affects different sites within the body, but has its most profound impact on the organs with the highest oxygen requirement. CO concentration and the intensity and duration of inhalation determine the extent of intoxication. Following basic life support, assisted or controlled ventilation with 100% oxygen is essential during emergency care. Hyperbaric oxygenation (HBO) is the preferred therapeutic option for releasing CO from its binding to haemoglobin. It has been shown that CO may cause lipid peroxidation and leukocyte-mediated inflammatory changes in the brain, a process that may be inhibited by HBO. Patients with neurological symptoms including loss of consciousness and expectant mothers should undergo HBO treatment, no matter how high their CO levels are. Neonates and in-utero fetuses are more vulnerable due to the natural leftward shift of the dissociation curve of fetal haemoglobin, a lower baseline pO2 and carboxyhaemoglobin levels at equilibration that are 10-15% higher than maternal levels. Physicians need to be aware of the potential occurrence of this life threatening hazard so that appropriate emergency treatment can be administered and fatalities prevented.

Brain↗
PubMed2000

The carina as a landmark in central venous catheter placement.

Location of the tip of a central venous catheter (CVC) within the pericardium has been associated with potentially lethal cardiac tamponade. Because the pericardium cannot be seen on chest x-ray (CXR), an alternative radiographic marker is needed for correct placement of CVCs. The anatomy of the region was studied in 34 cadavers. The carina was a mean (SEM) distance of 0.4 (0.1) cm above the pericardial sac as it transverses the superior vena cava (SVC). In no case was the carina located below the pericardial sac. The carina is a reliable, simple anatomical landmark for the correct placement of CVCs. In almost all cases, the carina is radiologically visible even in poor quality, portable CXRs. CVC tips should be located in the SVC above the level of the carina in order to avoid cardiac tamponade.

Aged↗
PubMed1999

[Circulatory function and oxygenation during hemihepatectomy. Dopamine versus dopexamine].

OBJECTIVE: The aim of this study was to compare low dose dopamine and dopexamine with respect to of liver-venous oxygen saturation, oxygen delivery and--demand, liver function tests and cardiocirculatory effects in the reperfusion period during a hemihepatectomy operation with occlusion of the liver hilus. METHODS: Twenty patients were studied in a randomised, doubleblind setting. They either received 2 micrograms/kg per min dopamine or 0.5 microgram/kg per min dopexamine perioperatively. For monitoring purposes a pulmonary artery and a liver venous catheter were placed. At four different time points hemodynamic parameter were assessed and blood samples were drawn. RESULTS: Significant changes between groups were found 5 min after opening the liver hilus for the cardiac index and the systemic oxygen delivery, as well as at the end of the operation for pulmonary shunt volume, which had increased more in the dopexamine group. No significant difference between liver venous oxygen saturation and liver function tests was found. CONCLUSION: Until more detailed studies concerning the influence of dopamine on the hepatic-splanchnic region during liver surgery are performed, dopexamine can not be considered superior to dopamine during these operations.

Dopamine↗
PubMed1999

Septic shock after liver transplantation for Caroli's disease: clinical improvement after treatment with C1-esterase inhibitor.

The extent of complement and contact activation is related to outcome in sepsis. A low functional index of their main blocker C1-esterase inhibitor (C1-INH) is considered as a relative deficiency of C1-INH and might contribute to the development of fatal complications in the intensive care unit. The first results of therapeutic intervention with C1-INH concentrate in septic shock are promising. We report on our experience of C1-INH concentrate administration in a young woman with Caroli's disease as ultimate rescue therapy for septic shock with capillary leakage syndrome after combined liver and kidney transplantation. No focus of infection was detectable and thus surgical intervention was not indicated. Antibiotic therapy at that time included vancomycin, tobramycin, meropenem and fluconazol. Hemodynamic stabilization occurred within hours after administration of C1-INH concentrate. Simultaneously a reduction in vasopressor medication was possible and negative fluid balance was achieved.

Adult↗
PubMed1999

Victor Ivánchich (1812-1892) and Josef Weiger (1810-1863): early cooperation of a urologist and an anesthesiologist.

Today the cooperation of the highly developed specialities anesthesiology and urology is daily practice in every hospital and does not need further explanation in medical reports. The history of medicine tells us that the situation was different during the pioneer days of surgery in the last century. Although the statement that the patient underwent surgery while under general anesthesia was mostly included in the reports of operations at that time, the need for a specially trained doctor to perform anesthesia was hardly recognized. Most surgeons delegated this task to young colleagues or even to persons who had not been medically trained. The urologic surgeon Victor Ivánchich may have been an exception in including his special anesthesiologist Josef Weiger in several of his publications on lithotrity.

Anesthesiology↗
PubMed1999

Xenon inhalation increases airway pressure in ventilated patients.

BACKGROUND: The inert gas xenon, known as an anaesthetic for nearly 50 years, is also used as a contrast agent during computerised tomography (CT)-scanning. As xenon has a higher density and viscosity than air, xenon inhalation may increase airway resistance. METHODS: In a retrospective study we investigated the effects of 33% xenon/67% oxygen on airway pressure and cardio-respiratory parameters in 37 long-term mechanically ventilated patients undergoing cerebral blood flow (rCBF) measurements by means of stable xenon-enhanced CT. RESULTS: Xenon administration caused a significant increase in peak airway pressure from 31.6+/-8.0 cm H2O to 42.7+/-16.9 cm H2O. This effect was reproducible, did not occur after reduction of inspiratory flow rate by 50% from 0.56+/-0.15 L x s(-1) to 0.28+/-0.08 L x s(-1), and vanished immediately after termination of xenon delivery. CONCLUSION: Due to the higher density and viscosity of this gas mixture, ventilation with xenon/oxygen produces a higher Reynolds' number than oxygen/air when given at the same flow rate. This means that during xenon ventilation the zone of transition from turbulent to laminar gas flow may be located more peripherally (in smaller airways) than during oxygen/air ventilation with a subsequent increase in airway resistance. Our results indicate that xenon inhalation may cause a clinically relevant increase of peak airway pressure in mechanically ventilated patients.

Administration, Inhalation↗
PubMed1999

Voltage-dependent block of normal and mutant muscle sodium channels by 4-Chloro-m-Cresol.

1 The effects of 4-Chloro-m-Cresol (4-CmC) were examined on heterologously expressed wild type (WT), Paramyotonia Congenita (R1448H) and Hyperkalemic Periodic Paralysis (M1360V) mutant alpha-subunits of human muscle sodium channels. 2 Block of rested sodium channels caused by 4-CmC was concentration-dependent with an ECR50 of 0.40 mM in WT, 0.45 mM in R1448H and 0.49 mM in M1360V. 3 Inactivation significantly promoted 4-CmC-induced sodium channel block in all clones indicated by 4-CmC-induced shifts of steady-state availability curves, reflecting a higher proportion of channel block at depolarized membrane potentials. Channel block was almost complete (>90%) at concentrations close to the ECR50 (0.5 mM) on application of an inactivating prepulse before the test pulse. 4 4-CmC accelerated the current decay following depolarization and prolonged recovery from inactivation in all clones. Of these, R1448H, the mutant which displayed severely impaired inactivation in the controls, responded to 4-CmC with the most pronounced acceleration of inactivation. Control experiments revealed enhanced recovery from inactivation in the mutants, which was restored to normal in 0.1 mM 4-CmC. 5 4-CmC induced no additional frequency-dependent block. 6 Our results clearly demonstrate that 4-CmC is as effective as lidocaine (Fan et al., 1996) in blocking muscle sodium channels. Low concentrations of the compound (</=ECR50) were able to restore pathologically accelerated recovery from inactivation and impaired inactivation in the mutants to the WT value.

Amino Acid Substitution↗
PubMed1999

[The continuous monitoring of hepatic venous oxygen saturation in patient monitoring following hemihepatectomy].

UNLABELLED: Increasing numbers of liver tumours and liver metastases from other tumours are treated by liver resection. During resection the ligamentum hepatoduodenale is occluded and the liver is exposed to warm ischemia. Duration and intensity of resulting liver ischemia can not be evaluated without special monitoring devices. A fiberoptic catheter placed in a liver vein facilitates continuous recording of the hepatic-venous oxygen saturation (ShvO2). CASE REPORT: We present a case where such a catheter was placed perioperatively in a patient undergoing hemihepatectomy. The liver venous catheter was positioned by guidance of the saturation curve and X-ray. The preoperative oxygen saturation in this liver vein was 80%. During the whole operation, the ShvO2 was continuously monitored. Blood for blood gas analyses was drawn before, during and after the occlusion of the ligamentum hepatoduodenale. Hemodynamic parameters were documented at the same time. The ShvO2 already decreased in the preparation period before the actual occlusion of the ligamentum hepatoduodenale. During the occlusion the ShvO2 dropped to an average of 30% with the lowest value being 13%. After reopening of the hepatic hilus the ShvO2 increased rapidly but did not reach preoperative values which were recorded not earlier than at the end of the operation. CONCLUSION: Duration and intensity of the decreased ShvO2 were recognized early by the liver venous catheter. It was demonstrated that desaturation of the hepatico-splanchnic region already occurred during the period of liver preparation before the ligamentum hepatoduodenale was occluded. Interventions to protect the liver from ischemia should therefore be applied some time before occlusion of the liver hilus. However, clearly defined indications for this invasive monitoring cannot be given at this time. In situations of extended liver resection or in cases of expected technical difficulties a continuous monitoring of the liver-venous oxygen saturation might be beneficial.

Adult↗
PubMed1999

Different effects of dopamine and dopexamine on the isolated perfused rat kidney.

We have investigated the effect of dopamine and dopexamine on the isolated perfused rat kidney. After an equilibration period of 20 min and two control periods of 10 min, dopexamine 1.0, 2.5 or 4.0 micrograms kg-1 min-1 or dopamine 2.0 micrograms kg-1 min-1 were perfused for a further 40 min in random order. Renal blood flow, urine volume, glomerular filtration rate, absolute sodium excretion and fractional sodium reabsorption of the isolated perfused kidney were measured every 10 min during the experiment. Dopamine increased significantly urine production from mean 61.54 (SEM 4.7) to 117.2 (9.7) microliters min-1 g-1 and absolute sodium excretion from 0.4 (0.1) to 1.2 (0.1) mumol min-1 g-1, and decreased significantly fractional sodium reabsorption from 97.3 (0.5) to 90.7 (0.7)%. Renal blood flow and glomerular filtration rate were not altered. In contrast, dopexamine had no effect on the isolated kidney. These data suggest that the diuretic and natriuretic effects of dopexamine in humans may not result from a direct action on the kidney.

Adrenergic beta-Agonists↗
PubMed1999

Increased reading speed for stories presented during general anesthesia.

BACKGROUND: In the absence of explicit memories such as the recall and recognition of intraoperative events, memory of auditory information played during general anesthesia has been demonstrated with several tests of implicit memory. In contrast to explicit memory, which requires conscious recollection, implicit memory does not require recollection of previous experiences and is evidenced by a priming effect on task performance. The authors evaluated the effect of a standardized anesthetic technique on implicit memory, first using a word stem completion task, and then a reading speed task in a subsequent study. METHODS: While undergoing lumbar disc surgery, 60 patients were exposed to auditory materials via headphones in two successive experiments. A balanced intravenous technique with propofol and alfentanil infusions and a nitrous oxide-oxygen mixture was used to maintain adequate anesthesia. In the first experiment, 30 patients were exposed randomly to one of the two lists of 34 repeated German nouns; in the second experiment, 30 patients were exposed to one of two tapes containing two short stories. Thirty control patients for each experiment heard the tapes without receiving anesthesia. All patients were tested for implicit memory 6-8 h later: A word stem completion task for the words and a reading speed task for the stories were used as measures of implicit memory. RESULTS: The control group completed the word stems significantly more often with the words that they had heard previously, but no such effect was found in the anesthetized group. However, both the control and patient groups showed a decreased reading time of about 40 ms per word for the previously presented stories compared with the new stories. The patients had no explicit memory of intraoperative events. CONCLUSIONS: Implicit memory was demonstrated after anesthesia by the reading speed task but not by the word stem completion task. Some methodologic aspects, such as using low frequency words or varying study and test modalities, may account for the negative results of the word stem completion task. Another explanation is that anesthesia with propofol, alfentanil, and nitrous oxide suppressed the word priming but not the reading speed measure of implicit memory. The reading speed paradigm seems to provide a stable and reliable measurement of implicit memory.

Adult↗
PubMed1999

Compositional, structural, and functional alterations in pulmonary surfactant in surgical patients after the early onset of systemic inflammatory response syndrome or sepsis.

OBJECTIVES: Sepsis is one of the most important predisposing factors for the development of the acute respiratory distress syndrome (ARDS). Alterations of pulmonary surfactant contribute in the pathogenesis of ARDS. However, little is known about surfactant in patients with less severe grades of lung injury related to sepsis or systemic inflammatory response syndrome (SIRS). Therefore, the purpose of this study was to characterize endogenous surfactant in surgical intensive care patients with sepsis or SIRS. DESIGN: Prospective, observational study. SETTING: University-affiliated, interdisciplinary intensive care unit. PATIENTS: Eleven patients after major surgery with SIRS or sepsis included within 12 hrs of onset and 11 controls without infection or lung disease. INTERVENTIONS: Operating room and standard intensive care unit management. MEASUREMENTS AND MAIN RESULTS: Four serial bronchoalveolar lavage samples (BAL) were recovered over 7 days from the patients and single BAL samples were obtained from controls. BAL cells, total protein, surfactant-associated protein A (SP-A), surfactant alveolar transition forms, and surface activity were analyzed. Two of 11 patients met criteria for acute lung injury and six of the 11 patients met ARDS consensus conference criteria but acute lung injury or ARDS was not persistent. The mean Pao2/F(IO)2 for the patients over 7 days was 253.2+/-15.1 (SEM) and Murray's lung injury score was 1.12+/-0.12, indicating mild-to-moderate lung injury. BAL neutrophil counts were increased (p< .01), and the ratio of poorly functioning light aggregate surfactant to superiorly functioning heavy aggregate surfactant was increased compared with controls (0.32+/-0.06 vs. 0.09+/-0.01, p < .05). SP-A was decreased (1.9+/-0.4 vs. 3.5+/-0.6 microg/mL of BAL, p< .05) and there were increases in the ratios of phospholipid to SP-A (p < .05), protein to SP.A (p < .01), and protein to phospholipid (p < .05). The surface tension-lowering ability of purified heavy aggregate surfactant was significantly impaired (15.6+/-1.6 vs. 2.8+/-0.6 milliNewtons/m, p< .05). CONCLUSIONS: These observations show that surgical patients with SIRS or sepsis who have mild-to-moderate lung injury develop surfactant dysfunction detectable within 7 days of onset. We propose, therefore, that therapeutic strategies to modulate these severe surfactant abnormalities should be considered, as these strategies may have the potential to reduce lung injury, which is associated with a high mortality in sepsis.

APACHE↗
PubMed1998

[Cerebral hemodynamics during implantation of cardioverter-defibrillator systems].

OBJECTIVE: During ICD-implantation it is necessary to prove the function and to determine the optimal threshold by means of induced ventricular fibrillation (VF). Provoked cardiac arrests cause a circulator stop of the cerebral perfusion. Our aim was to examine the changes of cerebral blood flow velocity (CBFV(MCA)) after induced VF depending on the duration of fibrillation and prior values of CBFV(MCA). PATIENTS AND METHODS: Sixty induced episodes of VF in 9 patients (mean age +/- SD 53.5 +/- 8 years) were examined during ICD-implantation. Beside the standardized anaesthesiological monitoring, transcranial Doppler sonography was used to record the cerebral blood flow velocity in the middle cerebri artery CBFV(MCA). The duration of the fibrillation-period and the range and duration of the CBFV increase during the post defibrillation-period were correlated. Additionally, we examined whether systematic differences existed between the episodes of each patient (time-trend) by means of 5 following episodes of a patient. RESULTS: During all episodes of VF and hyperperfusion was present, that means a time interval showing increased values of CBFV(MCA), compared to the values present before VF. The duration of hyperperfusion depended significantly on the fibrillation time (r = 0.57; p < 0.001). The equation of regression is: hyperperfusion time = 11.1 + 1.22 x fibrillation time. The amount of hyperperfusion, that means the maximal CBFV after defibrillation, increase significantly with CBFV(MCA) before VF (correlation = 0.88; p < 0.001). The equations of regression is hyperperfusion height = 6.11 + 1.22 x CBFV(MCA) before VF. The duration of hyperperfusion is not influenced by the maximal CBFV(MCA) after defibrillation (r = 0.08; p = 0.52). In the examined patients no significant differences in the hyperperfusion time maximal CBFV(MCA) after defibrillation between the episodes were found. CONCLUSION: After induced VF you always have to expect a reactive cerebral hyperperfusion. The amount of increase of CBFV after defibrillation depends on the prior values of CBFV before fibrillation and shows a nearly proportional relation to these. The duration of hyperperfusion shows a linear dependency on VF-times. This may show that we had VF-times, in which the cerebral autoregulation and other cerebral physiological reactions compensate the drop of the CBFV(MCA) during VF in the postfibrillation time. In further studies will be examined if there are similar changes in the cerebral metabolism as in CBFV(MCA).

Adult↗
PubMed1998

Anesthesiological management during isolated liver perfusion.

The treatment of irresectable hepatic metastases is limited by the systemic toxicity of anticancer agents. Isolated hyperthermic liver perfusion (IHLP) with anticancer agents is a new therapy for irresectable liver tumors. The risks of this therapy lie in the extended operation, the anhepatic phase and the possibility of liver damage due to the anticancer drug and hyperthermia. Experience of this method is rare, and the side effects are not well known. To estimate the individual risk of patients before isolated liver perfusion an extended evaluation of the preoperative conditions is usual. Titration of all anesthetic agents is advisable to prevent cardiovascular changes and to avoid an extended recovery time after therapy. Based on our experience with IHLP in ten patients, we prefer coinduction with midazolam and thiopentone. After intubation, intermittent positive pressure ventilation with positive end-expiratory pressure is instituted with 30% oxygen in air. Pancuronium bromide is used to provide muscular paralysis, and isoflurane is administered throughout the procedure. Anesthesia is supplemented by fentanyl and midazolam. Invasive hemodynamic monitors may be placed after induction of anesthesia. Our first results with IHLP indicate that, under the conditions of elevated monitoring, complete isolation of the liver, a good wash-out and a safe anesthesiological management, no major disturbances must be expected during the therapy. The patients are more compromised by the therapy during the following days. Low diastolic blood pressure and loss of resistance after perfusion were the first signs of a toxic reaction.

Adult↗
PubMed1998

Standard calculation of ethanol elimination rate is not sufficient to provide ethanol substitution therapy in the postoperative course of alcohol-dependent patients.

OBJECTIVE: Alcohol withdrawal syndrome (AWS) is a severe complication during postoperative treatment of alcohol-dependent patients. Besides the use of clomethiazole, clonidine, and benzodiazepines, there is another possible way to prevent AWS by deliberate administration of ethanol. The appropriate dosage of ethanol has not been known up to now and it could be defined according to the average ethanol elimination rate (EER) which, from forensic analysis, is known to be 15 mg/dl per h in a normal population. However, it is questionable whether these data are suitable for the calculation of the correct dosage in alcohol-dependent patients. DESIGN: Preliminary retrospective descriptive study. SETTING: Intensive care unit of a university teaching hospital. PATIENTS: 11 alcohol-dependent patients (9 males, 2 females, mean age 50.8 years, range 33 to 60 years). INTERVENTIONS: Ethanol substitution (ES) by parenteral application. MEASUREMENTS AND RESULTS: Ethanol kinetics were evaluated by repeated measurement of the blood ethanol concentration (BEC) over a period of at least 6 h parallel to the administration of ethanol. The average EER was found to be 28 mg/dl per h with a standard deviation of 11 mg/ dl per h. The minimum value was 18 mg/dl per h and the maximum 50 mg/dl per h. These EERs were significantly higher than the EERs known from forensic analysis. AWS was prevented in all 11 patients. CONCLUSIONS: Close control of BEC and precise adjustment of ethanol administration are necessary prerequisites for ES. The standard EER is not sufficient to define the appropriate ethanol dosage due to enormous variations in the ethanol metabolism of alcohol-dependent patients.

Adult↗