Biomedical subjects

Gunter Hempelmann

Publications and source records attributed to Gunter Hempelmann.

At least 55 records · Page 3Linked to original sources

PubMed2003

Lidocaine and octanol have different modes of action at tetrodotoxin-resistant Na(+) channels of peripheral nerves.

UNLABELLED: Local anesthetics and alcohols block impulse conduction in peripheral nerves by inhibiting Na(+) currents. In small peripheral nerve fibers, tetrodotoxin-resistant (TTX-r) Na(+) channels play an important role in impulse generation. We investigated the effects of lidocaine and the alcohol octanol on TTX-r Na(+) channels. Currents were recorded with the whole-cell patch-clamp method from enzymatically isolated rat dorsal root ganglion cells (data evaluation: nonlinear least-squares fitting). Lidocaine and octanol blocked the TTX-r Na(+) current in a reversible and concentration-dependent manner (50% inhibitory concentration values: 177 +/- 25 and 455 +/- 25 microM, respectively). Lidocaine additionally produced a strong use-dependent block. Both drugs showed a strong dynamic block (i.e., block developed during the time course of current activation and inactivation). Double-pulse protocols showed a slow dissociation of lidocaine from the channel during repolarization (time constant: 1763 +/- 63 ms; 300 microM). The dissociation of octanol was too quick to be distinguished from normal current repriming kinetics of 2.2 ms. Lidocaine and octanol acted noncompetitively in the Na(+) channel. Lidocaine and octanol have different blocking properties on the TTX-r Na(+) current and bind to different channel sites. IMPLICATIONS: Lidocaine and octanol have different inhibitory effects on the function of tetrodotoxin-resistant Na(+) channels in rat dorsal root ganglion cells, as well as noncompetitive modes of action, as investigated by the whole-cell patch-clamp method, and therefore are likely to have different binding sites on the channel.

1-Octanol↗

PubMed2003

Indicators of erythrocyte damage after microwave warming of packed red blood cells.

BACKGROUND: Localized overheating of packed red blood cells (PRBCs) after microwave warming with consequent damage to erythrocytes has been reported. We therefore compared possible cellular markers of erythrocyte damage, as measured by flow cytometry, with laboratory indicators of hemolysis to evaluate the effects of microwave warming on PRBCs. METHODS: PRBC samples were warmed to room temperature or to 37, 42, 47, 52, or 57 degrees C in a water bath. Flow cytometry was performed after fluorescein labeling using antibodies to spectrin, Ca(2+)-ATPase, and Na(+)-K(+)-ATPase. The forward-to-sideward scatter (FSC/SSC) ratio and antibody binding were evaluated. Plasma free hemoglobin (FHb) and alpha-hydroxybutyrate dehydrogenase (HBDH) were measured immediately after heating and after 48 h. In addition, all measurements were made before and after the heating of PRBCs to 35 degrees C by a microwave blood warmer. RESULTS: Analysis of 15000 erythrocytes showed a decrease in the FSC/SSC ratio and antibody binding above 47 degrees C [at 37 degrees C, median (SD) of 94.2 (7.4) with 0.07 (0.05)% fluorescein-positive; at 52 degrees C, median (SD) of 177.0 (19.0) with 18.5 (6.4)% positively gated; P <0.001]. FHb [room temperature, 0.3 (0.2) g/L] was increased 2-fold at 37 and 42 degrees C, 4-fold at 47 degrees C, and 25-fold at 52 degrees C. HBDH increased in parallel. Hemolysis markers showed an additional twofold increase 48 h after heating to 42 and 47 degrees C. Microwave heating to 35 degrees C did not produce significant changes of any marker. CONCLUSIONS: All markers of cellular damage were altered after heating to >47 degrees C, and a substantial part of hemolysis was delayed. The methodology can be used for future testing of other blood warming devices.

Biomarkers↗

PubMed2002

Trichloroethanol alters action potentials in a subgroup of primary sensory neurones.

We investigated the effects of 2,2,2-trichloroethanol (TCE), the active metabolite of chloral hydrate, on large-conductance calcium-activated K+ channels (BKCa channels) of dorsal root ganglion (DRG) neurones. In outside-out patches, 2 and 5 mM TCE increased the open probability of BKCa channels to 1.7-fold and 2.8-fold of control, respectively. In 50% of the cells investigated (group A) the action potential (AP) was shortened reversibly by TCE by 20% and the whole-cell outward-current was increased by 44%. Both effects could be antagonized by iberiotoxin. In a second group of neurone (group B), TCE prolonged the AP duration. The effects of TCE in group A, which was 20-fold more potent than ethanol on BKCa channels and AP might contribute to the described analgesic effect of chloral hydrate.

Action Potentials↗

PubMed2002

Sensory neurons respond to hypoxia with NO production associated with mitochondria.

Oxygen is pivotal for mammalian cell function, and recent studies suggest an involvement of NO in cellular adaptation to low oxygen supply. Here, we report that endothelial NO-synthase is ubiquitously expressed in rat and mice sensory neurons, and is targeted to juxtamitochondrial compartments of the ER. There it is activated in response to hypoxia while generation of reactive oxygen species remains unaltered. Developing a technique for ultrastructural localization of an NO-sensitive indicator allowed to identify the inner mitochondrial membrane as the target of NO under hypoxia. The demonstrated hypoxic stimulation of endothelial NOS in sensory neurons shall contribute to resistance against hypoxia, since NO promotes cellular survival by interfering with mitochondrial function.

Animals↗

PubMed2002

Alterations of acute phase reaction and cytokine production in patients following severe burn injury.

To determine the acute immunologic reaction, mediated by cytokines, interleukines (ILs) and growth factors and the susceptibility to infections and sepsis after severe burn injury a prospective, single unit, longitudinal study of acute phase reactants and mediators who performed. After approval by the ethics committee of our hospital, we investigated the plasma concentrations of IL-2, -6, -8, -10, and -13, the soluble IL-2 receptor (sIL-2R), and the acute phase proteins procalcitonin (PCT) and C-reactive protein (CRP) at admission and every 3 days in 24 patients over a time course of 28 days after thermal injury and categorized by percent burn: < or =30% (group 1; n=12) and >30% (group 2; n=12). Shortly after burn injury we found higher concentrations of IL-2, -6, -10 and PCT in those patients >30% TBSA. During the study period, we found significant higher levels of acute phase proteins, IL-6 and -8 in patients >30% TBSA. The incidence of SIRS and MODS was three times increased in patients >30% TBSA. Our results show different patterns of cytokines and acute phase proteins in patients with different burned surface areas over a long time and continuous monitoring of a more distinct inflammatory response in these patients.

Acute-Phase Proteins↗

PubMed2002

Automatic calculation of a modified APACHE II score using a patient data management system (PDMS).

OBJECTIVE: To investigate a fully automated and modified APACHE II score calculation exclusively based on routine data supplied by patient data management system, the ICUData, and to assess the predictive performance of this score using analysis of discrimination and calibration at an operative ICU. METHOD: SQL scripts (calculation programs) were developed to calculate the scores of 524 patients who stayed at the ICU between April 1st, 1999 and March 31st, 2000. The calculation programs considered unavailable data as 'not pathological'. The main outcome measure was survival status at ICU discharge. The discriminative power on mortality of this modified APACHE II score was checked with a receiver operating characteristic (ROC) curve. Calibration was tested using the Hosmer-Lemeshow goodness-of-fit test. RESULTS: The 459 survivors had an average APACHE score of 17.8+/-5.3. The score of the 65 deceased patients averaged 22.7+/-4.6. The area under the ROC curve of 0.790 was significantly >0.5 (P<0.01) and had a 95% confidence interval (CI) of 0.712-0.825. The goodness-of-fit test showed a good calibration (H=4.89, P=0.70, dof 7, C=6.96, P=0.541, dof 8). CONCLUSION: A prediction model based on completely automatically calculated 'modified APACHE II scores' can be constructed using data collected with PDMS. However, due to differences in the patient collective and methods used, the results need validation and can only be partially compared to results from other studies.

APACHE↗

PubMed2002

Computerize anesthesia record keeping in thoracic surgery--suitability of electronic anesthesia records in evaluating predictors for hypoxemia during one-lung ventilation.

OBJECTIVE: The aim of this retrospective study was to assess the suitability of routine data gathered with a computerized anesthesia record keeping system in investigating predictors for intraoperative hypoxemia (SpO2 < 90%) during one-lung ventilation (OLV) in pulmonary surgery. METHODS: Over a four-year period data of 705 patients undergoing thoracic surgery (pneumonectomy: 78; lobectomy: 292; minor pulmonary resections: 335) were recorded online using an automated anesthesia record-keeping system. Twenty-six patient-related, surgery-related and anesthesia-related variables were studied for a possible association with the occurrence of intraoperative hypoxemia during OLV. Data were analyzed using univariate and multivariate (logistic regression) analysis (p < 0.05). The model's discriminative power on hypoxemia was checked with a receiver operating characteristic (ROC) curve. Calibration was tested using the Hosmer-Lemeshow goodness-of-fit test. RESULTS: An intraoperative incidence of hypoxemia during OLV was found in 67 patients (9.5%). Using logistic regression with a forward stepwise algorithm, body-mass-index (BMI, p = 0.018) and preoperative existing pneumonia (p = 0.043) could be detected as independent predictors having an influence on the incidence of hypoxemia during OLV. An acceptable goodness-of-fit could be observed using cross validation for the model (C = 8.21, p = 0.370, degrees of freedom, df 8; H = 3.21, p = 0.350, df 3), the discriminative power was poor with an area under the ROC curve of 0.58 [0.51-0.66]. CONCLUSIONS: In contrast to conventional performed retrospective studies, data were directly available for analyses without any manual intervention. Due to incomplete information and imprecise definitions of parameters, data of computerized anesthesia records collected in routine are helpful but not satisfactory in evaluating risk factors for hypoxemia during OLV.

Adult↗

PubMed2002

Enhancement of delayed-rectifier potassium conductance by low concentrations of local anaesthetics in spinal sensory neurones.

Combining the patch-clamp recordings in slice preparation with the 'entire soma isolation' method we studied action of several local anaesthetics on delayed-rectifier K(+) currents in spinal dorsal horn neurones. Bupivacaine, lidocaine and mepivacaine at low concentrations (1 - 100 microM) enhanced delayed-rectifier K(+) current in intact neurones within the spinal cord slice, while exhibiting a partial blocking effect at higher concentrations (>100 microM). In isolated somata 0.1 - 10 microM bupivacaine enhanced delayed-rectifier K(+) current by shifting its steady-state activation characteristic and the voltage-dependence of the activation time constant to more negative potentials by 10 - 20 mV. Detailed analysis has revealed that bupivacaine also increased the maximum delayed-rectifier K(+) conductance by changing the open probability, rather than the unitary conductance, of the channel. It is concluded that local anaesthetics show a dual effect on delayed-rectifier K(+) currents by potentiating them at low concentrations and partially suppressing at high concentrations. The phenomenon observed demonstrated the complex action of local anaesthetics during spinal and epidural anaesthesia, which is not restricted to a suppression of Na(+) conductance only.

Analysis of Variance↗

PubMed2002

Long-term monitoring of renal function in poly-traumatized intensive care patients.

INTRODUCTION: For the long-term monitoring of kidney function, polytraumatized patients were examined and routine as well as specialized parameters were compared. MATERIALS AND METHODS: 30 patients of the Surgical Intensive Care Unit (ICU) were examined daily over the entire period they stayed in the ICU. The patients were retrospectively classified as either survivors or deceased patients. Group 1 consisted of 20 patients who resided in the ICU for 11-15 (Median 14) days before they could be transferred to a normal hospital unit. Group 2 consisted of 10 patients who had passed away after 13-18 (Median 16) days in the ICU. In addition to the routine parameters diuresis, serum creatinine and serum urea, specialized parameters for kidney function including the excretion rates of alpha1-microglobulin (alpha1-MG), N-Acetyl-beta-D-glucosaminidase (NAG), angiotensinase A (ATA) and immunoglobulin G (IgG) were determined. RESULTS: Similar biometric data were shown by all patients at admission into the ICU, but differences did exist regarding the Revised Trauma Score, Injury Severity Score and the APACHE-II-Score. In the period between the 5th and 8th day of intensive treatment almost all patients showed pathological excretion rates of tubular and glomerular parameters whereby no increased frequency of unusual events could be determined at these time-points. CONCLUSION: During treatment in the ICU, all examined patients showed at times pathological excretion rates of specialized kidney function parameters. Such transient damage was only apparent in a few of the patients when the standard parameters serum creatinine and serum urea were employed. In 90% of the surviving patients the kidney parameters had normalized until the time they were transferred, indicating that such parameters reflected the general state of health of these patients.

Acetylglucosaminidase↗

PubMed2002

The incidence and risk factors for hypotension after spinal anesthesia induction: an analysis with automated data collection.

UNLABELLED: We sought to identify factors that are associated with hypotension after the induction of spinal anesthesia (SpA) by using an anesthesia information management system. Hypotension was defined as a decrease of mean arterial blood pressure of more than 30% within a 10-min interval, and relevance was defined as a therapeutic intervention with fluids or pressors within 20 min. From January 1, 1997, to August 5, 2000, data sets from 3315 patients receiving SpA were recorded on-line by using the automatic anesthesia record keeping system NarkoData. Hypotension meeting the predefined criteria occurred in 166 (5.4%) patients. Twenty-nine patient-, surgery-, and anesthesia-related variables were studied by using univariate analysis for a possible association with the occurrence of hypotension after SpA. Logistic regression with a forward stepwise algorithm was performed to identify independent variables (P < 0.05). The discriminative power of the logistic regression model was checked with a receiver operating characteristic curve. Calibration was tested with the Hosmer-Lemeshow goodness-of-fit test. The univariate analysis identified the following variables to be associated with hypotension after SpA: age, weight, height, body mass index, amount of plain bupivacaine 0.5% used for SpA, amount of colloid infusion before puncture, chronic alcohol consumption, ASA physical status, history of hypertension, urgency of surgery, surgical department, sensory block height of anesthesia, and frequency of puncture. In the multivariate analysis, independent factors for relevant hypotension after SpA consisted of three patient-related variables ("chronic alcohol consumption," odds ratio [OR] = 3.05; "history of hypertension," OR = 2.21; and the metric variable "body mass index," OR = 1.08) and two anesthesia-related variables ("sensory block height," OR = 2.32; and "urgency of surgery," OR = 2.84). The area of 0.68 (95% confidence interval, 0.63-0.72) below the receiver operating characteristic curve was significantly greater than 0.5 (P < 0.01). The goodness-of-fit test showed a good calibration of the model (H = 4.3, df = 7, P = 0.7; C = 7.3, df = 8, P = 0.51). This study contributes to the identification of patients with a high risk for hypotension after SpA induction, with the risk increasing two- or threefold with each additional risk factor. IMPLICATIONS: By using automated data collection, 5 (chronic alcohol consumption, history of hypertension, body mass index, sensory block height, and urgency of surgery) of 29 variables could be detected as having an association with hypotension after spinal anesthesia induction. The knowledge of these risk factors should be useful in increasing vigilance in those patients most at risk for hypotension, in allowing a more timely therapeutic intervention, or even in suggesting the use of alternative methods of spinal anesthesia, such as titrated continuous or small-dose spinal anesthesia.

Aged↗

PubMed2002

Small-dose nitric oxide improves oxygenation during one-lung ventilation: an experimental study.

UNLABELLED: Inhaled nitric oxide (NO) at 20 or 40 ppm does not improve arterial oxygenation during one-lung ventilation (OLV). The authors hypothesized that NO at smaller concentrations might improve oxygenation. Twelve piglets weighing 26 to 32 kg were studied. When PaO(2) had reached a plateau during OLV, NO at doses of 4, 8, 16, and 32 ppm were randomly administered for 30 min. Hemodynamic data were determined by invasive monitoring. Blood gas analysis and, in six animals, ventilation-perfusion analysis by the multiple inert gas elimination technique were used to characterize pulmonary gas exchange. NO at 4, 8, 16, and 32 ppm improved PaO(2) during OLV. NO at 4 ppm had a more intense effect on arterial oxygenation than doses of 8, 16, and 32 ppm (DeltaPaO(2), 42 +/- 35 mm Hg versus 22 +/- 20 mm Hg, 13 +/- 18 mm Hg, and 15 +/- 16 mm Hg; P < 0.05). NO at 4 ppm reduced intrapulmonary shunt flow, whereas a larger concentration exhibited no statistically significant effect. The authors conclude that NO improves arterial oxygenation more effectively at smaller doses than at larger doses. This dose-dependent effect remains to be confirmed in acute hypoxemia during OLV. IMPLICATIONS: Inhaled nitric oxide at 4 ppm improves arterial oxygenation during one-lung ventilation to a greater extent than larger doses, and this effect is caused by a reduction in intrapulmonary shunt.

Animals↗

PubMed2002

Discriminative power on mortality of a modified Sequential Organ Failure Assessment score for complete automatic computation in an operative intensive care unit.

OBJECTIVE: To evaluate the discriminative power on mortality of a modified Sequential Organ Failure Assessment (SOFA) score and derived measures (maximum SOFA, total maximum SOFA, and delta SOFA) for complete automatic computation in an operative intensive care unit (ICU). DESIGN: Retrospective study. SETTING: Operative ICU of the Department of Anesthesiology and Intensive Care Medicine. PATIENTS: Patients admitted to the ICU from April 1, 1999, to March 31, 2000 (n = 524). Data from patients under the age of 18 yrs and patients who stayed <24 hrs were excluded. In the case of patient readmittance, only data from the patient's last stay was included in the study. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The main outcome measure was survival status at ICU discharge. Based on Structured Query Language (SQL) scripts, a modified SOFA score for all patients who stayed in the ICU in 1 yr was calculated for each day in the ICU. Only routine data were used, which were supplied by the patient data management system. Score evaluation was modified in registering unavailable data as being not pathologic and in using a surrogate of the Glasgow Coma Scale. During the first 24 hrs, 459 survivors had an average SOFA score of 4.5 +/- 2.1, whereas the 65 deceased patients averaged 7.6 +/- 2.9 points. The area under the receiver operating characteristic (ROC) curve was 0.799 and significantly >0.5 (p <.01). A confidence interval (CI) of 95% covers the area (0.739-0.858). The maximum SOFA presented an area under the ROC of 0.922 (CI: 0.879-0.966), the total maximum SOFA of 0.921 (CI: 0.882-0.960), and the delta SOFA of 0.828 (CI: 0.763-0.893). CONCLUSION: Despite a number of differences between completely automated data sampling of SOFA score values and manual evaluation, the technique used in this study seems to be suitable for prognosis of the mortality rate during a patient's stay at an operative ICU.

Adult↗

PubMed2002

Renal effects of cardiopulmonary bypass in the elderly.

Cardiopulmonary bypass is widely believed to be injurious to renal function. The unknown consequences of renal dysfunction with modern techniques of bypass in the elderly caused us to examine creatinine clearance and the excretion of sensitive marker proteins in older adult patients undergoing CABG. Thirty male patients were divided into three groups: group I with an age up to 60 years, group II with an age between 61 and 70 years, inclusive and group III 71 years and over. Serum creatinine and urea, creatinine clearance, and alpha1-microglobulin (alpha1-MG), N-acetyl-beta-D-glucosaminidase (NAG), Tamm-Horsfall protein (TH) and immunoglobulin G (IgG) were all measured daily, pre- and postoperatively. Creatinine clearance remained lower in the older patients without significant differences. Raised excretion rates of alpha1-MG, and IgG were seen after CPB. The increase in alpha1-MG and NAG during the postoperative period revealed tubular damage in all elderly patients. Measurements of alpha1-MG, NAG and IgG represent useful supplements to standard clinical tests for recognizing early and differentiated changes in renal function.

Acetylglucosaminidase↗

PubMed2002

Effects of propofol and taurine on intracellular free amino acid profiles and immune function markers in neutrophils in vitro.

We have examined the effects of propofol, taurine, and the combination of propofol and taurine on amino acid profiles and the immune function markers superoxide anion (O2-), hydrogen peroxide (H2O2), and released myeloperoxidase (MPO) activity in neutrophils (PMN). Propofol led to significant changes in the dynamic PMN-free amino acid pool. Exogenous taurine significantly reduced PMN neutral amino acid and alpha-aminobutyrate (alpha-aba) as intracellular taurine increased. Incubation with propofol plus taurine resulted in lower intracellular taurine levels and elevated alpha-aba and neutral amino acid concentrations compared to propofol alone. Concerning PMN immune function markers, propofol significantly decreased O2- and H2O2 formation and released MPO. Taurine led to an increased release of MPO and concomitant significantly reduced O2- and H2O2 levels. When propofol and taurine were applied together they appeared to act additively with regard to superoxide and hydrogen peroxide formation. In the case of MPO, taurine neutralized propofol's effects, supporting the idea that MPO activity may be regulated by taurine. We believe therefore that taurine is important for strengthening PMN host defense capability, although the mechanisms are not yet clear. Moreover, taurine appears to act primarily by altering the PMN osmotic balance, while propofol seems to affect PMN amino acid metabolism and/or uptake and release.

Adult↗

PubMed1996

RETRACTED: The role of the protein C-thrombomodulin system and fibrinolysis during cardiovascular surgery: influence of acute preoperative plasmapheresis.

OBJECTIVES: To assess the benefits of withdrawn autologous plasma, the objective of this study was to investigate whether withdrawal of acutely performed platelet-rich or platelet-poor plasmapheresis allays changes in the protein C-thrombomodulin and fibrinolytic systems after retransfusion secondary to cardiopulmonary bypass (CPB). In addition, the study attempted to determine the influence of acute plasmapheresis (APP) on the protein C-thrombomodulin and fibrinolytic systems as well as on homologous blood consumption and perioperative blood loss in elective aortocoronary bypass patients. DESIGN: The investigation was scheduled as a prospective, randomized, unblinded study. SETTING: This single investigation was conducted in the Department of Anesthesiology and Intensive Care Medicine at a university in Germany. The study protocol was approved by the Ethics Committee of the hospital, and informed consent was obtained. PARTICIPANTS: Sixty male patients scheduled for elective coronary artery bypass grafting with extracorporeal circulation were included in the study. INTERVENTIONS: APP was performed between induction of anesthesia and incision, collecting either 10 mL/kg of autologous platelet-poor plasma (PPP patients, group 1; n = 20) or the same amount of platelet-rich plasma (PRP patients, group 2; n = 20). Patients of group 3 (n = 20) had no APP (control group). All patients were maintained on their usual regimen of cardiac drugs until the morning of surgery. To preserve hemodynamic stability and restore the intravascular oncotic pressure, the separated plasma was replaced by infusion of an equal amount of hydroxyethyl starch solution (HES) (6% HES, molecular weight 2 x 10(5), substitution rate 0.5%). In all operations, the same surgical procedure was chosen. For all patients, induction and maintenance of anesthesia were similar, consisting of weight-related doses of fentanyl (35 micrograms/kg), midazolam (0.65 mg/kg), and pancuronium bromide (0.15 mg/kg). The lungs of all patients were mechanically ventilated during the first 5 hours after the end of the operation. MEASUREMENTS AND MAIN RESULTS: All patients had serial coagulation studies including antithrombin (AT) III-activity, prekallikrein, factor XII, and immunologic tests such as thrombin-antithrombin III (TAT), fibrinopeptide A (FPA), protein C and S (PC and PS), thrombomodulin (TM), tissue-plasminogen-activator (t-PA), plasminogen-activator-inhibitor (PAI 1), fibrinopeptide B beta 15-42 (FPB beta 15-42), D-dimers, and hemoglobin and platelet counts determined intraoperatively and postoperatively. Chest tube drainage and transfusion requirements were recorded. APP had no negative effects on the quality of PPP and PRP plasma. The platelet count of the withdrawn plasma was 28 +/- 12 x 10(9)/L (PPP group) and 245 +/- 36 x 10(9)/L (PRP group). At the end of the operation (after retransfusion of autologous plasma) and on the morning of the first postoperative day, platelet counts were significantly higher (p > 0.05) in the PRP than in the PPP and control groups. Plasma concentrations of TAT and FPA increased (ranging from +185% to +340% from baseline values) and AT III-activity, PC, PS, and TM antigen decreased (ranging from -8% to -55% from baseline values) to a different extent for all three groups throughout CPB. t-PA-activity increased with a maximum at the end of CPB (PPP group, 6.9 +/- 1.5 IU/mL: PRP group, 3.8 +/- 0.8 IU/mL; control group, 10.9 +/- 2.8 IU/mL). Fibrin and fibrinogen degradation markers such as D-dimers and FPB beta 15 to 42 occurred in peak concentrations after neutralization of heparin by protamine. Only PRP patients showed baseline concentrations of coagulation parameters the next morning (p < 0.05). Total postoperative blood loss within the first 24 hours reached 482 +/- 273 mL (PRP group), 775 +/- 256 mL (PPP group), and 948 +/- 342 mL in the control group (p < 0.05).(ABSTRACT TRUNCATED)

Adult↗

PubMed1996

Changes in heart rate variability during induction of anesthesia with fentanyl and midazolam.

OBJECTIVE: The study was designed to evaluate changes in autonomic nervous system function during induction of anesthesia with fentanyl, midazolam, and pancuronium and to answer the question of dose-dependency of these effects. DESIGN: Prospective, randomized. SETTING: A university hospital. PARTICIPANTS: Forty consecutive cardiac surgical patients. INTERVENTIONS: Anesthesia was induced with fentanyl, midazolam, and pancuronium. The patients were assigned to four groups differing in dosages of fentanyl plus midazolam and speed of injection. Fentanyl, 7.5 micrograms/kg (group A), 12.5 micrograms/kg (group B), and 20.0 micrograms/kg (group C) plus midazolam, 0.075 mg/kg (group A), 0.125 mg/kg (group B), and 0.200 mg/kg (group C) were administered over 10 minutes; in group D, fentanyl, 7.5 micrograms/kg, and midazolam, 0.075 mg/kg, were administered within 1 minute. MEASUREMENTS AND MAIN RESULTS: Heart rate variability (HRV) was measured using parameters in the time domain and the frequency domain. The comparison of preinduction HRV with the intra-anesthetic epochs did not show significant differences with respect to heart rate, coefficient of variation, and root mean squared successive differences. Spectral analysis showed significant reductions of power in the vasomotor band (0.01 to 0.05 Hz) and the low-frequency band (0.05 to 0.15 Hz) in all groups. Power in the high-frequency band (0.15 to 0.50 Hz) decreased slightly, but this did not reach the significance level. A dose dependency of these changes was found in the low-frequency band only. CONCLUSIONS: Parameters of HRV suggest that induction with fentanyl, midazolam, and pancuronium decreases sympathetic but not parasympathetic autonomic system activity. The anesthetic induction technique's modulation of autonomic nervous system balance is better represented by means of spectral analysis than by analysis in the time domain. This modulation was largely independent of the doses administered and independent of the speed of injection.

Adult↗

PubMed1993

RETRACTED: Influence of acute preoperative plasmapheresis on platelet function in cardiac surgery.

Withdrawal of autologous plasma offers the possibility of improving patients' hemostasis and of reducing homologous blood consumption in cardiac surgery. The influence of acute, preoperatively performed plasmapheresis (APP) on platelet function was investigated in elective aortocoronary bypass patients subjected to APP producing either platelet-poor plasma (PPP; group 1; n = 12) or platelet-rich plasma (PRP; group 2; n = 12). APP-treated patients were randomly compared to patients without APP (control group; n = 12). Platelet aggregation induced by ADP (concentration 0.25, 0.5, 1.0, and 2.0 mumol/L), collagen (4 microL/mL), and epinephrine (25 mumol/L) was determined by the turbidometric method before and after APP, as well as before and after cardiopulmonary bypass (CPB) until the morning of the 1st postoperative day. APP had no negative effects on the patients' aggregation parameters (maximum aggregation and maximum gradient of aggregation). The platelet counts in the withdrawn plasma were 25 +/- 10 x 10(9)/L (PPP-group) and 250 +/- 30 x 10(9)/L (PRP-group). Platelet counts were highest in the PRP-group at the end of the operation (after retransfusion of autologous plasma). After CPB, maximum aggregation and maximum gradient of aggregation were reduced in all groups (ranging from -6% to -25% from baseline values). Retransfusion of autologous plasma improved platelet aggregability significantly only in the PRP-group. By the first postoperative day, maximum aggregation and maximum gradient of aggregation recovered in all groups (including the control group) or even exceeded baseline values (ranging from +8% to +42% from baseline values.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Coagulation Tests↗

PubMed1992

RETRACTED: Right ventricular function in patients with reduced left ventricular function undergoing myocardial revascularization.

Complex interrelationships exist between the right (RV) and the left ventricles (LV). Therefore, in 30 consecutive patients with reduced LV function (left ventricular ejection fraction [LVEF]) less than 40% undergoing myocardial revascularization, RV hemodynamics were studied from the beginning of anesthesia until the end of the operation. The data were compared with 30 consecutive patients with normal LVEF (greater than 70%). Ventricular function was assessed during left heart catheterization, which was carried out within 1 month of the operation. In addition to standard hemodynamic variables, RV ejection fraction (RVEF), RV end-diastolic volume (RVEDV), and RV end-systolic volume (RVESV) were monitored by the thermodilution technique. The two groups did not differ preoperatively with regard to RVEF, pressure (MAP, PAP, PCWP, RAP, RVPsyst, RVEDP), cardiac index (CI), and volume variables (RVESV, RVEDV). However, when the group with preoperatively reduced LVEF was subdivided into patients with severely reduced LVEF (less than 30%; n = 14; mean value 25.1%) and patients with moderately reduced LVEF (30%-40%; n = 16; mean value 37.3%), RVEF was significantly lower in the patients with a LVEF below 30% throughout the entire investigation period. RVEDV and RVESV were significantly higher in these patients. In conjunction with the lower RVEF and normal PAP, this suggests reduced RV function. It can be concluded that a severely reduced preoperative LVEF (less than 30%) may also be associated with impaired RV function.

Analysis of Variance↗