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Biomedical subjects

G Hempelmann

Publications and source records attributed to G Hempelmann.

At least 397 records · Page 22Linked to original sources
PubMed1989

[Homologous fresh frozen plasma in heart surgery. Myth or necessity].

Routine administration of homologous fresh frozen plasma (FFP) is widely carried out in cardiac surgery although the risks of blood transfusion can never be excluded. The effect of two units of FFP (430 +/- 11 ml) given after the end of extracorporeal circulation (ECC) (group 1, n = 20) was compared to a control group (n = 20) without FFP in elective aorto coronary bypass patients. Various laboratory parameters, including coagulation data, were measured before and after the end of ECC up to the 1st postoperative day. The patients were comparable with regard to biometric data, anesthesia, and surgical procedure. The major result of this study shows, that routine administration of FFP has no beneficial effect with respect to hemostatic balance. In comparison to a control group, the increase in elastase and decrease in paO2 was even more pronounced in the FFP group. Both blood loss and the need for blood transfusion did not differ between the groups. It can be concluded that a bleeding tendency in cardiac surgery may be caused by ECC itself and by perioperative plasma loss. The routine administration of a relatively small amount of FFP has no positive influence on hemostasis. Substitution therapy in this situation should be guided by the results of coagulation studies.

Aged↗
PubMed1989

[Preoperative normvolemic hemodilution in heart surgery. Pulmonary changes with the use of new technics].

Interest in preoperative hemodilution (HD) has intensified perceptibly again, because of the increasing risk of adverse reactions to donor blood. However, in coronary surgery patients the use of HD is still the subject of controversy, as it may possibly influence organ function and especially lung water content. New techniques, including membrane oxygenation, extracorporeal circulation (ECC) with only "partial" bypass due to 2-stage cannulation, and hemoconcentration with cell separators, have significantly modified patient management in the field of cardiac surgery. Therefore, the influence of moderate hemodilution (12 ml/kg) on extravascular lung water (EVLW) was investigated under these conditions in 45 patients with coronary artery disease. Volume replacement was performed either with hydroxyethyl starch solution (HD-HES group, n = 15, ratio of replacement 1:1) or with Ringer's lactate (HD-RL-group, n = 15, ratio 2.5:1); 15 patients not subjected to HD served as controls. ECC was carried out with membrane oxygenators only in partial bypass. Both during and after ECC, blood was concentrated by means of a cell-saving system allowing separation and reinfusion of the red cells while the plasma is discarded. EVLW was measured using a double-indicator dilution technique with indocyanine green. Starting from comparable baseline values, EVLW was not significantly changed by hemodilution. After ECC, however, the HD-RL group showed a significant increase in lung water content (means: +2.49 ml/kg equal 42.6%), whereas this was not significantly changed in the other groups. By 5 h after ECC, the lung water content had returned to baseline values and no more differences could be observed between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Body Water↗
PubMed1989

[Sympatho-adrenergic reactions following theophylline administration with the use of various anesthesia technics].

The mechanism of action of theophylline is still the subject of controversy. Possible mechanisms that have been suggested are inhibition of phosphodiesterase, release of catecholamines, effects on intracellular calcium, and adenosine antagonism. With regard to these aspects, it was the aim of this study to compare sympatho-adrenal responses after theophylline application during different anesthetic techniques. A total of 60 patients scheduled for orthopedic surgery were investigated: they were divided into three groups of 20 patients who received either halothane anesthesia with thiopentone induction, modified neurolept anesthesia with fentanyl and midazolam, or spinal anesthesia with bupivacaine and mepivacaine. Within these three groups, the patients were randomly allocated to a theophylline collective receiving an injection of theophylline, 4 mg/kg body weight and to the control group. Plasma levels of epinephrine and norepinephrine (by HPLC/ECD), glucose, lactate and free glycerol and MAP and HR were determined over a period of 120 min. In all groups, epinephrine levels increased immediately after injection of theophylline; group levels of epinephrine were higher in the theophylline-groups than in controls (P less than 0.0001). A remarkable increase was observed within 60 min. Peak epinephrine concentrations were comparable after single injections of 100 micrograms or infusions of 5 micrograms/min. The norepinephrine increase after theophylline injection was brief and less pronounced. MAP, HR, glucose, lactate and free glycerol were not influenced by theophylline. A comparison of the theophylline patients showed no statistical differences attributable to the different anesthetic techniques.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Does the development of methemoglobin in the newborn infant affect the suitability of prilocaine for pudendal anesthesia? A clinical study in the peripartum phase].

Pudendal block is a well established method of achieving analgesia during the second stage of labor. Whenever a large amount of a local anesthetic has to be injected in well vascularized tissue, local anesthetic drugs with low systemic toxicity should be used, to minimize side effects. This means that prilocaine is the drug of choice. It is well known that the metabolites of prilocaine induce methemoglobinemia, and thus the question arises as to whether the methemoglobinemia affects the fetus. PATIENTS AND METHODS. Pudendal block was achieved with 2 x 10 ml prilocaine 1% in each of 17 mothers. Plasma concentrations of the local anesthetic in the second stage of labor were determined by gas chromatography in blood samples drawn from the mother and the newborn at the moment of childbirth. In addition, the time course of methemoglobinemia was determined by capillary blood samples from the neonate up to 6 h. To evaluate methemoglobinemia in the newborn, 125 microliters heparinized capillary blood was diluted with 200 microliters 0.9% sodium chloride; methemoglobin was detected by absorbance spectrometry. RESULTS. Before the pudendal block maternal methemoglobin concentrations were about 0.2% of the total hemoglobin concentration and within the physiological range. At the moment of delivery it was increased only to a small extent, without statistical significance. In the neonates mean methemoglobin concentrations were about 1% of total hemoglobin immediately after delivery, increasing up to 1.8% in the next 2 h and then decreasing continuously in all. At the moment of childbirth maternal mean prilocaine concentrations were 0.57 micrograms/ml on an average and 0.29 micrograms/ml in the newborn. DISCUSSION. With respect to systemic toxicity, prilocaine is the drug of choice in local anesthetic procedures when a long duration of anesthesia is not required; it guarantees short latency and adequate relief of pain. Methemoglobinemia induced by its metabolites is not a contraindication for its use in humans. Formerly prilocaine was judged to be contraindicated in pregnant women during delivery because of the small redox capacity of fetal erythrocytes. Our study, however, demonstrates that 200 mg prilocaine for pudendal block does not induce methemoglobinemia in newborns to any significant extent. One explanation for this may be the increased renal elimination of local anesthetics in newborns and the low fetomaternal ratio.

Anesthesia, Obstetrical↗
PubMed1989

[The quantitative analysis of amide local anesthetics using high pressure liquid chromatography and ultraviolet detection (HPLC/UV)].

This study was undertaken to develop a time- and cost-effective method for the detection of lidocaine, mepivacaine, prilocaine, bupivacaine, and etidocaine by HPLC/UV. The chromatographic system consisted of a C18-column (300 x 3.9 mm) for reversed-phase chromatography and a mobile phase of 30% acetonitrile and 70% 0.05 M sodium phosphate buffer. For the analysis of lidocaine, mepivacaine, and prilocaine, the buffer was adjusted to pH 5.8. The buffer for the analysis of bupivacaine and etidocaine was adjusted to pH 3.5. The flow rate was 1 ml/min. UV detection took place at a wavelength of 210 nm. All blood samples were taken from a central venous line. After plasma separation, 1 microgram (100 microliters) of internal standard was added to 1 ml plasma. The samples were alkalized and extracted with ether, followed by the extraction of the organic phase in 250 microliters 0.05 N sulphuric acid; 50 microliters of this solution was injected into the system. The chromatographic system allowed the separation of bupivacaine and etidocaine (pH 3.5) as well as lidocaine and mepivacaine or prilocaine (pH 5.8). Separation of prilocaine and mepivacaine in one run was not satisfactory. Recovery rates for all local anesthetic substances were about 90%, standard variations below 3%, and coefficients of variation below 2%. The detection limit was about 30 ng/ml. The method is suitable for clinical practice. Only minor methodological modifications are necessary for the detection of the amide local anesthetics in current clinical use.

Anesthetics, Local↗
PubMed1989

[Initial experiences with a novel nerve stimulator for use in axillary plexus anesthesia].

The advantages of an electrical nerve stimulator for detection of the axillary neurovascular sheath have been frequently described in the literature and are now well known. In most of these techniques, stimulation is achieved by a fixed electrical voltage and variable amplification. The new nerve stimulator presented here offers the possibility of measuring the current at the site of stimulation ("test" position). PATIENTS AND METHODS. Axillary block was performed in 23 patients undergoing orthopedic surgery. Identification of the neurovascular sheath was first achieved by the "loss of resistance" technique, after which the injection cannula was connected to the new device. Stimulation was started at 1.0 mA. In case of a negative response to stimulation the actual electric current was checked by means of the test position in order to exclude an error in the circuit system. In these cases, the position of the cannula was altered so as to maintain a response at the lowest possible current (less than 0.5 mA). After removal of the inner solid steel stylet of the cannula, the local anesthetic was injected while compressing the distal part of the neurovascular sheath in order to avoid downstream diffusion. RESULTS. All 23 patients were operated upon under axillary block after nerve stimulator control without any additional drugs. Table 2 indicates the lowest stimulation current that still evoked a response. Disturbances in the circuit system were found twice, one caused by a short circuit, the other by a desiccated gel pad on the adhesive electrode. After elimination of the defect, stimulation produced a response. DISCUSSION. Since it is now well known that induction of paresthesias in locating peripheral nerves can cause irreversible lesions, the use of electrical nerve stimulators is preferred to locate the cannula as near as possible to the nerve without direct contact. The mode of operation of the stimulator presented here, which defines the chosen technical starting impulse as well as the actual current, allows much better localization of nerves during local anesthesia. Thus, disturbances in the circuit between nerve stimulator and patient, as shown in the two cases, can be detected. According to our experience, the intensity of stimulation for successful nerve blockade should be approximately 0.5 mA or lower. Consequently, universally applicable stimulating instruments with constant electrical tension should allow fine tuning of the current in 0.1-mA aliquots.

Brachial Plexus↗
PubMed1989

Blood conservation in cardiac operations. Cell separation versus hemofiltration.

The effects of hemoconcentration performed during and after extracorporeal circulation by either centrifugation (cell separation group, n = 20) or hemofiltration (n = 20) were investigated in 40 patients undergoing elective aorta-coronary bypass grafting. Interest was focused on the quality of the blood concentrated from the blood remaining in the extracorporeal circuit and on the reaction of the patients after retransfusion of the concentrated products. Hemofiltration was easy to perform and produced whole blood quicker than the cell separation technique. Coagulation studies revealed no significant differences in heparin concentration, levels of fibrinogen and antithrombin III, or platelet counts. Various coagulation parameters tended to normalize completely and more quickly after hemofiltration than after centrifugation. None of the patients had severe bleeding postoperatively. Free hemoglobin levels were not affected by hemofiltration; elastase concentration was higher only immediately after retransfusion of the concentrated blood, with no effect on organ function. We conclude that both methods were effective means of hemoconcentration during extracorporeal circulation and in salvaging the diluted pump blood after extracorporeal circulation. Loss of plasma fraction is an important disadvantage in the centrifugation technique, which can be avoided by hemofiltration; derangement in colloid osmotic pressure and coagulation parameters was less pronounced after hemofiltration. Costs were lower, as well. Therefore, when a high volume of cardioplegic solution and two-stage cannulation are used, hemofiltration seems to be the method of choice for blood conservation during cardiac operations.

Aged↗
PubMed1989

[Hyperthermic reaction in the perioperative phase in 2 children with acute lymphoblastic leukemia of B-cell type].

Acute lymphatic leukemia (ALL) represents one of the most frequent malignancies in childhood. Central venous access ports or partly implanted silicone catheters are usually placed for high-dose chemotherapy in these children. We report two patients aged 7 and 3 years with acute lymphoblastic beta-cell leukemia (B-ALL), a less common subtype of ALL, which presented with hyperthermia (38.4 degrees C and 39 degrees C) during anesthesia with isoflurane for implantation of a central venous catheter. The hyperthermic reactions were accompanied by an increase in expired CO2 and acidosis as well as moderate elevation of heart rate and blood pressure. As in both patients the history and preoperative findings did not reveal signs of infection or other causes of fever, the observed alterations were interpreted as symptoms of malignant hyperthermia triggered either by succinylcholine or isoflurane, which were used in both children. In addition, the hyperthermia responded to administration of dantrolene sodium according to dose recommendations for treatment of malignant hyperthermia. In one of the patients, withdrawal of dantrolene during the initial postoperative hours was followed by a recurrent increase in body temperature, which once again could be suppressed by additional dantrolene infusion. According to the literature, malignant hyperthermia has occasionally been described in children with malignancies such as leukemia or Burkitt's lymphoma. Our observations indicate that children with B-ALL may be especially susceptible to malignant hyperthermia. Close monitoring of body temperature and expiratory CO2 are therefore indicated in these children, and dantrolene therapy should be started immediately in case of increased temperature during anesthesia.

Anesthesia, Inhalation↗
PubMed1988

Interactions between nimodipine and general anaesthesia--clinical investigations in 124 patients during neurosurgical operations.

Haemodynamic, respiratory, metabolic and endocrine investigations were performed in a total number of 124 patients, divided into four different groups, during opiate anaesthesia for neurosurgical operations in order to characterize general effects of nimodipine, a calcium channel blocking agent with a preferential cerebrovascular action. These studies led to the following conclusions: Nimodipine is a vasodilator drug with a hypotensive action, which is especially obvious in hypertensive patients and in combination with similarly acting agents, such as sodium nitroprusside or nitroglycerin. This vascular hypotensive effect may be also enhanced by combined cardiodepressive activity if nimodipine is applied together with inhaled anaesthetics, such as halothane or isoflurane. Nimodipine as well as other vasodilator drugs may lead to increased pulmonary shunting in patients with artificial ventilation, which, however, can be reduced by adequate positive end-exspiratory pressure. With high doses the decrease of oxygen extraction and consumption, seen with nimodipine, is accompanied by a moderate rise of lactate. Determination of stress hormones did not reveal analgesia potentiation of nimodipine, as has been assumed in other studies.

Anesthesia, General↗
PubMed1988

Influence of acute preoperative hemodilution on right ventricular function.

In a randomized study, the effects of acute, preoperative hemodilution (HD) (12 mL/kg) on right ventricular function were investigated in coronary artery surgery patients with reduced left ventricular function (ejection fraction < 50%) and significant stenosis of the right coronary artery (RCA). Blood was replaced either by hydroxyethyl starch (HES) solution (ratio 1:1; HD-HES; n = 15) or by Ringer's lactate, (RL) (ratio 2.5:1; HD-RL; n = 15). Fifteen comparable patients without HD served as a control group. Besides commonly measured pressure parameters, right ventricular end-diastolic volume (RVEDV), right ventricular end-systolic volume (RVESV), and right ventricular ejection fraction (RVEF) were measured using a computerized thermodilution technique before and after HD, as well as after extracorporeal circulation (ECC). Right ventricular systolic function, expressed as RVEF, was not changed significantly by HD in any group. Furthermore, right ventricular function of the hemodiluted patients was not impaired by the subsequent ECC procedure. None of the traditionally measured parameters could be correlated significantly to the right ventricular thermodilution variables. It is concluded that moderate HD does not change right ventricular function even when the RCA is significantly stenosed.

Aged↗
PubMed1988

Revascularization of the right coronary artery: influence on thermodilution right ventricular ejection fraction.

This study was designed in order to evaluate the influence of right coronary artery (RCA) disease and its revascularization on right heart performance monitored by measuring thermodilution right ventricular ejection fraction (RVEF). Forty patients undergoing elective aortocoronary bypass surgery were divided into two groups: group 1, with RCA revascularization, n=20; and group 2, without RCA disease or revascularization, n=20. RVEF was measured using a pulmonary arterial catheter mounted with a fast-response thermistor and a bedside microprocessor ejection fraction computer. The major finding of the study was that myocardial revascularization with extracorporeal circulation was followed by a decrease in RVEF which was significantly more pronounced in group 1 (-13.1%) in comparison to group 2 (-5.0%). RVEF gradually increased after bypass, but did not reach baseline values. By the first postoperative day, RVEF had reached baseline values again in group 1 and had increased beyond baseline values in group 2. Traditionally measured hemodynamic parameters could not be correlated with the course of RVEF, except for cardiac index. The present study further suggests that right-sided events may have clinical effects on left-sided function. Inadequate protection of the right heart, especially in patients with RCA stenosis, may result in depression of right ventricular myocardial performance, which can be monitored serially by measuring RVEF.

Blood Pressure↗
PubMed1988

Influence of dextran on the absorption of adrenaline-containing lignocaine solutions: a protective mechanism in local anaesthesia.

The effect of adding 6% dextran to a lignocaine solution containing adrenaline was studied in 27 neurosurgical patients during modified neuroleptanaesthesia. Before trepanation they received infiltration anaesthesia of the scalp at the site of the proposed operation. For a period of 1 h following injection plasma concentrations of adrenaline were measured by high pressure liquid chromatography and serum concentrations of lignocaine by gas chromatography. The addition of dextran caused a significant reduction in the absorption of both adrenaline and lignocaine from the injection site. It is concluded that the dextran adjuvant constitutes a protective mechanism against toxic systemic side effects in local anaesthesia using adrenaline-containing anaesthetic solutions. This effect is particularly significant in patients with pre-existing cardiovascular disease and when local anaesthetic solutions are used in combination with volatile anaesthetics.

Absorption↗
PubMed1988

Influence of acute normovolemic hemodilution on extravascular lung water in cardiac surgery.

Preoperative hemodilution (HD) is an established blood-saving method. With HD, however, a concomitant increase in extracellular and interstitial water has been reported. This randomized study was undertaken to compare the effects of acute normovolemic HD (10 ml/kg; n = 15) using hydroxyethyl starch solution (HES) on extravascular lung water (EVLW) with those of an untreated control group (n = 15) of cardiac surgery patients submitted to extracorporeal circulation (ECC). A thermal-dye technique was used to measure EVLW. There was no significant change in EVLW due to preoperative HD (5.55 +/- 0.51 vs. 5.71 +/- 0.59 ml/kg). After ECC, a transient increase in both groups could be demonstrated because of a possible change in pulmonary capillary permeability (maximal increase in the HD group: +1.30 ml/kg and in the nonHD group: +1.02 ml/kg). Five hours after ECC, no differences could be seen between the groups. Pulmonary gas exchange was not significantly affected (PaO2 in the HD group: -20 torr). Hemodynamic and laboratory variables indicated the typical changes during HD (cardiac index increases while albumin concentration decreases); circulatory stability was maintained during the entire study. We conclude that preoperative normovolemic HD did not increase lung water content significantly nor compromise pulmonary function even in cardiac surgery patients. Although ECC provides an additional HD (crystalloid priming of the heart-lung bypass machine) and possibly damage of capillary integrity, the two groups did not differ.

Body Water↗
PubMed1988

RETRACTED: Influence of PEEP ventilation immediately after cardiopulmonary bypass on right ventricular function.

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the request of the editor. In 2018, CHEST published a notice1 that all articles authored by Joachim Boldt be read with caution due to expressions of concern about falsified data. In 2020, CHEST received additional evidence of research misconduct and breaches of scientific integrity that were discovered following an investigation by the author's former institution, the University of Giessen2. In light of this new evidence, this article has been retracted by CHEST. 1. Irwin, R.S., MD, Master FCCP. Notice From the Editor in Chief. CHEST 153(3), p. 767. 2. Mukherjee, J. Statement on the scientific credibility of articles published by Joachim Boldt, formerly professor at Justus Liebig University (JLU), Giessen, Germany. https://ars.els-cdn.com/content/image/1-s2.0-S000709122030163X-mmc3.pdf.

Cardiac Output↗
PubMed1988

[Effect of acebutolol on plasma catecholamines and perioperative endocrine stress parameters].

In order to investigate the effect of intraoperative beta-blockade with acebutolol on the endocrine stress response during modified neuroleptanesthesia, 20 patients for major abdominal or thoracic surgery from ASA groups I-III were randomly allocated to the following groups: (1) control group without acebutolol treatment; or (2) treatment group, administration of 0.2 mg/kg acebutolol 5 min after induction of anesthesia. During a period of 30 min before operation, intraoperatively, and 30 min after the end of operation plasma levels of norepinephrine and epinephrine (by HPLC) and ADH, ACTH, and cortisol (by RIA) were measured. In addition, mean arterial pressure (MAP), HR, and plasma concentrations of glucose, lactate, and free glycerol were determined. Statistical evaluation was undertaken by analysis of variance with repeated measures on one factor, considering P values of less than 0.05 as significant. The administration of acebutolol had no influence on plasma catecholamine concentrations during the preoperative rest period. There was no evidence of any interaction between beta-blockade and plasma catecholamines. After induction of anesthesia, the levels of all hormones decreased. During the operation, there was a significant increase in all endocrine parameters measured. No differences were found between the treatment and control groups. All endocrine parameters reached their highest levels 30 min after the end of the operation. The differences in MAP, HR, glucose, lactate, and free glycerol between the groups failed to reach statistical significance.

Acebutolol↗