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Biomedical subjects

G Hempelmann

Publications and source records attributed to G Hempelmann.

At least 415 records · Page 23Linked to original sources
PubMed1988

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

The influence of nimodipine on plasma-catecholamines, ADH, ACTH and cortisol during standardized, modified neurolept-anaesthesia was investigated in 20 patients for major abdominal and thoracic surgery. The application of nimodipine led to an intra- and postoperative increase in both adrenaline and noradrenaline. No influence could be demonstrated on ADH, ACTH or cortisol. Group-levels of MAP were lower in the nimodipine-group. No statistical differences became obvious for HR, glucose, lactate and free glycerol. The increases in adrenaline and noradrenaline can be attributed to a cardiocirculatory rebound-phenomenon due to the vasodilative properties of the substance. Under the conditions of adequate fentanylanalgesia, no influence of nimodipine on ADH, ACTH or cortisol was found.

Adolescent↗
PubMed1988

[Sedative-analgesic medication in intensive care patients needing ventilator treatment].

UNLABELLED: It was the aim of this study to compare two regimens for sedation and analgesia during ventilator treatment in intensive care patients. Special regard was given to endocrine stress response, neuro-monitoring, hemodynamic parameters and clinical practicability. METHODS: A total number of 16 patients of an operative ICU were randomly allocated to the following groups: (1) Fentanyl-group, approximately 0.2 mg/h fentanyl, 2.5 mg/h midazolam and 2 mg/h pancuronium in intermittent doses, (2) ketamine-group, about 50 mg/h ketamine and 2.5 mg/h midazolam by syringe pump, in addition 2 mg/h pancuronium. During a period of 2 days and in intervalls of 6 h, plasma levels of epinephrine and norepinephrine (by HPLC/ECD), ADH, ACTH and cortisol (by RIA), ketamine (by GC) and stress-metabolites (glucose, lactate, free glycerol) were determined. Hemodynamic parameters were investigated in intervalls of 12 h, EEG (Compressed Spectral Array, CSA) in intervalls of 24 h. In addition, routine laboratory data, vigilance and adaptation to the respirator were observed. RESULTS: Plasma levels of adrenaline, noradrenaline, dopamine, ADH, ACTH, cortisol and stress-metabolites were comparable in both groups. Levels of ADH, ACTH, cortisol and free glycerol did not leave the normal range. In three patients, in which epinephrine- or norepinephrine-infusions were necessary to improve cardiocirculatory stability, this treatment could be finished after beginning of the ketamine application. In both groups, CSA showed a dominant delta- und theta-activity according to the clinical aspects of sufficient sedation and analgesia. Hemodynamic parameters were comparable in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

[Hemodynamic effects of benzodiazepines].

Benzodiazepines are of major interest in anesthesiology and intensive care medicine; they are indicated world-wide pre-, intra- and postoperatively. Application of these drugs is influenced by their side-effects such as hemodynamic changes, limiting their indication. The paper is focusing on general hemodynamic changes caused by benzodiazepines; the most important intravenous derivatives are reviewed with specific reference to their hemodynamic profile.

Anti-Anxiety Agents↗
PubMed1988

[Enoximone, a new phosphodiesterase inhibitor: the spectrum of applications during heart surgery--a comparison with dobutamine].

During cardiac surgery treatment of deterioration of myocardial function is usually based on catecholamines. Development of selective phosphodiesterase-(PDE-)III-inhibitors seems to be a new aspect in treating myocardial dysfunction. Therefore the hemodynamic effects of the new PDE-inhibitor enoximone were investigated in 20 coronary surgery patients unable to be weaned from extracorporeal circulation (ECC) without pharmacological intervention (MAP less than 60 mmHg, CI less than 2.00 l/min.m2, PCP greater than 15 mmHg). After controlled reperfusion with 2.4 1/min.m2 two groups were separated in a random sequence receiving either 0.5 mg/kg enoximone as a bolus (n = 10), or dobutamine (n = 10, 5 micrograms/kg.min) as perfusion. In the dobutamine-group MAP and CI (-14%) were decreased, while HR was increased significantly (+30%). Application of enoximone was followed by a slight increase in CI (+5%), a significant decrease in TSR while HR remained almost unchanged. PCP, too, differed significantly between the groups (enoximone: -38%; dobutamine: -10%). Ten minutes after weaning from ECC additional pharmacologic therapy (calcium, vasodilators, epinephrine) was necessary in eight dobutamine treated patients in contrast to four patients in the enoximone group (calcium, epinephrine). In patients with impaired myocardial performance during weaning from ECC enoximone seems to be an alternative therapy and is judged to be of some advantage compared to dobutamine application in this situation. The mechanism for improvement appears to be enhanced contractility owing to its positive inotropic effects, as well as a decrease in left ventricular outflow resistance resulting from peripheral vasodilation.

Aged↗
PubMed1988

[Hemodynamics in donor plasmapheresis].

Several studies have demonstrated that preoperative withdrawal and storage of autologous plasma as fresh frozen plasma is effective in blood conservation. For that purpose patients with elective surgery (orthopaedic surgery, open heart surgery, neurosurgery and others) have to undergo donor plasmapheresis without staying in the hospital. Depending upon the need the procedure can be performed several times preoperatively, taking about 900 ml in a normal weighting subject at once. The collection of autologous plasma should be finished at least 14 days before surgery. In order to investigate the haemodynamic effects of donor plasmapheresis 30 patients scheduled for coronary bypass surgery were devided into two groups. 15 patients underwent plasmapheresis (10 ml plasma/kgbw) by one-needle-technique using a Haemonetics seperator (PCS) after premedication but before onset of anaesthesia. Blood withdrawal was performed with 0.5 ml/kgbw x min. Another 15 patients, serving as control had no plasma withdrawal and were measured at identical times as the other group. Both groups had an identical fluid replacement with 500 ml Ringer's solution during the investigation period. Plasma withdrawn was not substituted by colloidal solution (simulating the situation when plasmapheresis is performed at the outpatient). Haemodynamic measurements (both groups) included heart rate, arterial blood pressure, right- and left-atrial pressure, systemic- and pulmonary-vascular resistance and cardiac output. There were no relevant effects of plasmapheresis on haemodynamic function during and after the investigation period in that patients: neither heart rate, blood pressure or vascular resistance changed significantly nor did pre- and afterload or cardiac index. No differences to the group without plasmapheresis could be observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Transfusion, Autologous↗
PubMed1988

[Experiences with parenteral administration of diltiazem in coronary surgery patients].

Diltiazem is a calcium channel blocker whose effects lie between those of the two other important calcium antagonists nifedipine and verapamil. In addition to vasodilation, it has a negative dromotropic effect with prolongation of the A-V interval. In animal experiments and human investigations, diltiazem improves the function of ischemic myocardium due to a direct dilating effect on coronary vessels. The purpose of the present study was to investigate the hemodynamic effects of diltiazem in patients before and during coronary revascularization. METHODS. The study included 60 consenting male patients with coronary heart disease. Twenty premedicated patients randomly received 0.3 mg/kg diltiazem or placebo within 3 min before induction of anesthesia. Hemodynamic measurements (arterial pressure, heart rate, mean pulmonary arterial pressure, pulmonary capillary pressure, right atrial pressure and cardiac output) were taken during the following 21 min. Before cannulation of the great vessels for institution of extracorporeal circulation (ECC), 20 other patients received 0.014 mg diltiazem or placebo/kg per min over 20 min. In addition to the above mentioned hemodynamic measurements, left ventricular parameters (LVP, LVEDP, dp/dt) were directly registered, and 5 min after the end of ECC the measurements were repeated with the same preload as before the ECC. Twenty additional patients received 0.014 mg diltiazem or placebo/kg per min within 21 min during ECC observing arterial perfusion pressure and oxygenator volume. RESULTS. Pre- and intraoperatively diltiazem caused a decrease in mean arterial pressure; cardiac index increased only during the preoperative investigation period (Tables 1, 2), whereas stroke volume index increased pre- and intraoperatively; heart rate decreased in all patients as well as dp/dt (Fig. 1).(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, General↗
PubMed1988

[Effect of opioids on granulocyte adherence].

The influence of clinically relevant concentrations of fentanyl, alfentanil, morphine, pethidine, and buprenorphine on polymorphonuclear neutrophilic granulocyte (PMN) adherence was investigated in vitro by using nylon fibre columns. Since none of the drugs produced any significant (p less than 0.05) change of adherence, no evidence of opioid mediated increased risk of postoperative bacterial infection could be found.

Adult↗
PubMed1988

[Alpha-mercaptopropionylglycine in the experimental hemorrhagic shock animal model].

Oxygen radicals may have an important role in the shock process. Several studies showed that stimulated polymorphological granulocytes altered biological membranes to a varying degree, especially in the pulmonary circulation. It could be demonstrated on isolated mitochondria that substances of the thiol group carrying SH-groups are capable of counteracting this damaging influence of toxic O2-metabolites. Furthermore the use of the thiol reagents was associated with an improvement in the mitochondrial energy situation (adenosine triphosphate increase). A total of 12 dogs were included into the study. Using standardised conditions haemorrhagic shock was induced by controlled bleeding. After reaching a mean blood pressure of 40 mmHg and a stabilisation of this stage, alternatively either 250 mg of alpha-mercaptopropionylglycine (therapy group T) or an equivalent volume of physiologic saline (controls K) were administered at random. In the dogs on controlled respiration the effect of the above-mentioned substance upon the haemodynamic of the total organism was monitored by means of continuous measuring of the arterial pressure by a Swan-Ganz catheter. Furthermore the acid-base balance, the electrolytes sodium, potassium and calcium were analyzed. Whereas the sodium and potassium values as well as the acid-base balance did not show any difference between both groups, the haemodynamic parameters partly showed very distinct differences, however, without being statistically significant in most cases. The administration of the thiol reagent (group T) led to a reduction in mean arterial pressure, heart rate, peripheral resistance and rate-pressure product. As far as the survival rate at the end of the study was concerned, no difference between the control and therapy group was seen.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗
PubMed1988

[Plasma concentrations of lidocaine and prilocaine following infiltration anesthesia in otorhinolaryngologic surgery].

UNLABELLED: Infiltration anaesthesia is still relevant for the surgical treatment of patients in otorhinolaryngology. The injection of local anaesthetics in well vascularised areas constantly causes the danger of high plasma concentrations of local anaesthetics combined with undesirable side effects. In our study we tried to determine the development of plasma concentrations of local anaesthetics in patients scheduled for routine tonsillectomies and tympanoplasty. MATERIALS AND METHODS: In 45 patients the development of plasma concentrations was measured immediately after the injection at short intervals; the samples were obtained between 1 minute and 60 minutes after the first injection. Group 1: Lidocaine 0.5% with epinephrine (1:200,000) 15-20 ml for tonsillectomy (n = 18). Group 2: Lidocaine 0.5% with epinephrine (1:200,000) 8-15 ml for tympanoplasty (n = 15). Group 3: Prilocaine 1% with epinephrine (1:200,000) 8-15 ml for tympanoplasty (n = 15). For tactical reasons infiltration anaesthesia for the patients of group 2 was - in addition to general anaesthesia - applied by the otorhinolaryngologist, whereas the patients of groups 1 and 3 were operated exclusively under local anaesthesia. RESULTS: Within the first minute after the initial injection plasma concentrations of the local anesthetic increased close to toxic threshold levels that are associated with undesirable systemic side effects. In the patients of group 1, who underwent tonsillectomy, plasma concentrations of 4-7 micrograms/ml were found during the first minute. The highest average values always appeared within the first five minutes: group 1 2.07 micrograms/ml, group 2: 0.45 micrograms/ml, and group 3: 1.15 micrograms/ml. DISCUSSION: With infiltration anaesthesia in well vascularised areas it may happen that there are--mainly in the early stage--high plasma concentrations of the applied substances, although the total dose was below the known maximum. Despite careful technique (repeated aspiration test in two levels) at least partial intravascular injections are apparently not always avoidable according to the pharmacokinetic data. Our results demonstrate that in addition to a safe peripheral venous line and prophylactic oxygen therapy, intraoperative monitoring of blood pressure, heart rate, electrocardiogram and verbal patient monitoring is of advantage in this group of patients. In our opinion the "standby function" of an anaesthesiologist can avoid severe complications.

Adolescent↗
PubMed1988

[Resuscitation and extravascular lung fluid in cardiac surgery].

Cardiovascular arrest may be followed by severe respiratory insufficiency due to an increase in the pressure in the pulmonary vascular system, an alteration in capillary permeability, or both. Extracorporeal circulation (ECC), on the other hand, can lead to a change in capillary integrity ('capillary leakage') caused by the unphysiologic perfusion patterns and/or activation of various mediator systems. Pulmonary hyperhydration (increased extravascular lung water [EVLW]) seems to be the most important factor limiting pulmonary function in this situation. This retrospective study was designed to investigate the influence of resuscitation in the period before ECC on pulmonary EVLW thereafter. Eight coronary surgery patients who had to be resuscitated in the period before the start of ECC due to cardiocirculatory arrest were compared to 8 patients without resuscitation selected randomly (control group). There were no differences between the two groups with regard to age, catheterization data, and ECC conditions. All patients underwent identical monitoring, including estimation of EVLW. Lung water measurement was performed by the thermal dye technique with indocyanine green (= non-diffusible indicator) dissolved in ice-cold dextrose (= diffusible indicator) and a bedside microprocessor before resusciation and after ECC (15 min, 45 min, 5h). Simultaneously, hemodynamics and parameters of pulmonary gas exchange were monitored. Baseline values of EVLW were comparable in both groups. After ECC a transient increase in EVLW could be demonstrated in the controls, indicating an altered fluid flux even in 'uncomplicated' courses; 5 h after ECC lung water content had again reached baseline values. In contrast, there was a significant increase in EVLW in the 'complicated group' immediately after ECC (+2.60 ml/kg) and 5 h after ECC (+1.38 ml/kg); in consequence, the paO2 was significantly decreased (-180 mmHg) while Qs/Qt was increased (+6.79%). It is concluded that the combination of two factors that potentially damage pulmonary tissue and increase lung water content (reanimation due to circulatory arrest and extracorporeal circulation) lead to a significant increase in extravascular lung water combined with a deterioration of pulmonary function, resulting in severe respiratory failure.

Capillary Permeability↗
PubMed1988

[Non-invasive versus invasive cardiovascular monitoring. Determination of stroke volume and pulmonary hydration using a new bioimpedance monitor].

Measurement of hemodynamic parameters by noninvasive techniques is gaining more and more popularity in the face of severe complications associated with invasive methods. Thoracic electrical bioimpedance is a noninvasive means of estimating cardiac output (CO) and pulmonary edema formation. The validity of this method, however, has been controversial. In the present study a new bioimpedance monitoring system (NCCOM 3) was used in 10 intensive care patients undergoing mechanical hemofiltration (group I) and in 20 cardiac surgery patients undergoing either aortic valve replacement (AVR, group IIa, n = 10) or aorto-coronary bypass grafting (CABG, group IIb, n = 10). In cardiac surgery patients the measurements were performed before as well as after extracorporeal circulation (ECC). CO measured by the impedance monitor was compared to the standard thermodilution method; pulmonary fluids were estimated by a thermo-dye technique and by measurement of total electrical impedance (base impedance), expressed as the thoracic fluid index (TFI). The principal finding of the study was that CO as measured by the two techniques differed significantly in all groups with regard to absolute values. The relative changes in CO, however, were comparable in both intensive care patients and CABG patients. In patients with special thoracic blood flow conditions (regurgitation in aortic insufficiency patients), no corresponding course of CO could be found.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗
PubMed1988

[Transcranial Doppler sonography as an intraoperative monitoring procedure. Initial experiences in aortocoronary bypass operations].

Changes in blood velocity in the middle cerebral artery (MFV) were investigated by transcranial Doppler sonography (TCD) in 24 patients undergoing aortocoronary bypass grafting before, during, and after extracorporeal circulation (ECC). Simultaneously, mean arterial blood pressure (MABP), PaCO2, PaO2, and hematocrit were recorded. During ECC, an increase in MFV could be observed that was most pronounced during the early bypass stages. After ECC, MFV decreased slightly but was significantly higher than before ECC. No linear relationship between MFV and MABP could be registered except for the early bypass stage. Neither duration of ECC nor aortic clamping time showed any correlation with MFV augmentation. Mean PaCO2 was held constant (36 mmHg) with PaO2 being at least 120 mmHg. After removal of the aortic clamp, high-frequency Doppler signals probably caused by air or fragment embolization were detected in some patients. Our data support previous observations of increased cerebral blood flow during nonpulsatile ECC. During short episodes of low-pressure perfusion after initiation of ECC, cerebral autoregulation seemed impaired. However, our results do not support the concept of complete loss of autoregulation during ECC. Compared to the xenon technique of measuring cerebral blood flow, TCD allows noninvasive and continuous evaluation of cerebral hemodynamics, thus offering new possibilities of monitoring cerebral blood supply intraoperatively.

Adult↗
PubMed1988

[Postoperative pain therapy by transdermal fentanyl].

INTRODUCTION: Several investigations have shown that constant rate infusions of opioids are highly effective in the provision of postoperative pain relief. However, such treatment require intravenous access, the availability of infusion pumps and adequate monitoring system. We have studied a transdermal fentanyl formulation (F-TTS, developed by ALZA Corporation, Palo Alto, USA) which should avoid these problems. METHODS: The study was performed in orthopaedic patients scheduled for hip arthroplasty. 40 patients were included consecutively in a double-blind parallel comparison of F-TTS (n = 20) and placebo (n = 20) patches. The patches were applied 0.5 hours prior to epidural anaesthesia and changed after 24 hours. F-TTS is designed to deliver fentanyl at the same rate of 75 micrograms/h. For 36 hours blood samples, pain scores, respiratory patterns and vital signs were collected frequently. Patients could have supplemental pethidine on demand (50 mg/2 h) if the pain relief was inadequate. RESULTS: Fentanyl blood concentrations increased (verum) during the 24 hours period (removal) and decreased slightly after that. At the end of the investigation (36 h) fentanyl concentration remained significantly elevated (about 60% of 24-hours value). F-TTS provided good postoperative pain relief although 11 patients (of 20) required supplemental pethidine. Patients with F-TTS, however had very little pethidine compared to patients with placebo. Two patients (one of each group) had to be eliminated from the study due to severe respiratory depression or inadequate pethidine requirement respectively. The incidence of other side effects such as nausea, vomiting and micturition difficulties were similar in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Cutaneous↗
PubMed1988

[Evoked potentials and inhalation anesthetics].

Intraoperative monitoring of evoked potentials can be affected by various factors including volatile anaesthetics. These effects have to be considered in order to give correct interpretations of the obtained data. Visual evoked potentials (VEP) and auditory evoked potentials (AEP) will show strong alterations under general anaesthesia whereas brainstem auditory evoked potentials (BAEP) are slightly affected. The effects of nitrous oxide, halothane, enflurane, and isoflurane on somatosensory evoked potentials (SEP) after median nerve stimulation were studied in 35 healthy adult patients. pCO2 and tympanic membrane temperature were held constant. Simultaneous cervical and cortical SEP recording was performed using surface electrodes. After induction of anaesthesia SEP were recorded during normoventilation with 100% oxygen and after inhalation of 66.6% nitrous oxide. 10 patients received halothane at inspired concentrations of 0.5, 1.0, 1.5, and 2.0%. After nitrous oxide had been replaced by oxygen, halothane was reduced in steps of 0.5%. SEP were recorded at the end of each period (15 min). Equipotent doses of enflurane or isoflurane were administered to 15 and 10 patients, respectively. Nitrous oxide depressed early cortical SEP amplitude. Halothane, enflurane, and isoflurane caused dose dependent increases of latencies. Reduction of amplitude was most pronounced with isoflurane. Using high doses of enflurane in oxygen cortical SEP showed unusual high amplitudes associated with marked increases of latencies. Even under high concentrations of volatile anaesthetics cervical SEP were minimally affected. The effects of anaesthetic gases have to be considered when SEP are recorded intraoperatively.

Anesthesia, Inhalation↗
PubMed1988

[Somatosensory evoked potentials in obliterating interventions of the carotid bifurcation].

A prospective study was undertaken to determine the prognostic value of somatosensory evoked potentials during carotid artery surgery in patients where an intraluminal shunt was not used. During a three-year period 167 patients underwent 193 consecutive carotid endarterectomies under general anaesthesia. The somatosensory evoked potential after median nerve stimulation including calculation of central conduction time was used to assess cerebral function intraoperatively. Early postoperative neurologic morbidity was 3.6%, mortality 0.6%. Evoked potential changes in these patients were uniform and consisted of an increase in central conduction time of more than 20% from control (anaesthetic baseline), a decrease of the amplitude of the primary cortical response exceeding 50% and a loss of middle latency components. In subsequent recordings complete loss of the entire cortical evoked potential was observed in 5 of 7 patients. Sensitivity of CCT prolongation was 100%, specificity 89% (18 false positives). For amplitude reduction sensitivity was 86% (1 false negative), specificity 96% (7 false positives). For loss of the entire cortical response sensitivity was 71% (2 false negatives), specificity 99% (2 false positives). The above mentioned parameters correlated with postoperative neurologic state (Chi-square, p = 0.0001). Since the effects of potentially confounding variables (anaesthetics, temperature) are well known, the somatosensory evoked response, especially central conduction time, can be used as a reliable guide for brain supporting procedures.

Brain Ischemia↗
PubMed1988

[Effect of dyshemoglobinemia (methemoglobinemia and carboxyhemoglobinemia) on accuracy of measurement in pulse oximetry in operations of long duration].

In two groups - eleven patients each - who underwent long lasting surgical procedures, arterial oxygen saturation was measured non-invasively (pulse oximeter) and invasively (CO-oximeter). In addition, total haemoglobin (THb), fractions of haemoglobin (metHb) and bloodgases were monitored. All patients of group I received an epidural anaesthesia via catheter with prilocaine combined with general anaesthesia. In group II a modified neurolept analgesia (balanced) was performed. As expepted we found a prilocaine-induced methaemoglobinaemia (metHb up to 11.6 Vol%) whereas in group II physiological values were not exceeded. Carboxyhaemoglobin up to 4 Vol% was found in the smokers of both groups, which decreased continuously - in contrast to metHb - during hyperoxic ventilation. Comparing the non-invasively and the invasively determined saturations no correlation (r = -0.002) was found in group I. However, a positive correlation (r = 0.652) was obtained in group II. After correction of SaO2 (pulse oximeter) using an adjusted formula a fair correlation (0.613) was found in group I, too. Using this equation for correction the correlation in group II increased to r = 0.824. Because of methodological facts (the pulse oximeter registers only desoxygenated haemoglobin) the arterial oxygen desaturation (O2Hb or fractional saturation) accompanying dyshaemoglobinaemia remains undetectable to the pulse oximeter. In the cases of known or expected dyshaemoglobinaemia pulse oximetry can yield only limited information; fractions of inactive haemoglobin should be measured by other means or accounted for by the given equation for correction (SaO2 corr. = SaO2 pulse oximeter - (COHb + metHb]. Pathophysiological effects of dyshaemoglobinaemia are discussed.

Abdomen↗