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Biomedical subjects

G Hempelmann

Publications and source records attributed to G Hempelmann.

At least 505 records · Page 28Linked to original sources
PubMed1985

[Catheter brachial plexus anesthesia for intra- and postoperative pain control. Plasma concentrations and analgesia interval in the use of bupivacaine].

In 15 orthopedic patients, undergoing plastic surgery of the upper extremity (elbow, forearm, hand) we studied plasma levels and pain free intervals, when performing catheter axillary plexus block with 0.5% and 0.25% bupivacaine as postoperative analgetic agent respectively. 30 minutes after injection of 40 ml of 0.5% bupivacaine maximum plasma levels were reached (means = 1.46 micrograms/ml), followed by a constant but slow decrease to 1 microgram/ml approximately after 2 h. 11.5 h (mean) after brachial plexus block there was a need for reinjection of local anesthetic solution for postoperative pain control. The pain free interval after 30 ml of 0.25% bupivacaine lasted 10.5 hours on the average. The 'top-up-dose' of 75 mg approximately equal to 30 ml of 0.25% bupicavaine caused only a small rise in plasma levels up to 0.6 micrograms/ml. Catheter brachial plexus block with bupivacaine is an appropriate procedure for both intra- and postoperative pain relief, especially in re-implantation surgery of the upper limb.

Adult↗
PubMed1985

[Comparative studies on dose adjustment of intraoperative lidocaine therapy in heart failure patients].

From 10 patients with myocardial insufficiency arterial blood samples were taken, in order to study lidocaine plasma concentrations following reduced iv. bolus administration (0.5 mg/kg body weight) and subsequent infusion (2 mg/min). Drug concentrations were monitored by means of gas chromatography. The results obtained from the reduced loading dose of lidocaine were nearly identical to those from patients without myocardial insufficiency and an iv. bolus injection of 1 mg lidocaine/kg body weight. The reduced hepatic metabolism of lidocaine caused by manifest myocardial insufficiency requires a significantly reduced loading dose not exceeding the therapeutic range, even in intraoperative short-term use.

Anesthesia, General↗
PubMed1985

[Effects of nitrous oxide and halothane on somatosensory evoked potentials after stimulation of the median nerve].

In 10 healthy adult subjects cervical and cortical somatosensory evoked responses (SEP) after median nerve stimulation were recorded. The recordings were performed before and after inhalation of 66 2/3% nitrous oxide (and 33 1/3% oxygen) and during additional inhalation of halothane in concentrations ranging from 0,5 to 2,0 vol%; end tidal paCO2 and tympanic membrane temperature were kept constant. Nitrous oxide caused a 50% amplitude reduction of the cortical responses while latencies remained unchanged. Latency of the primary cortical response N20 and central conduction time increased continuously with increasing halothane concentration, amplitude N20P25 and amplitude ratio R showed a further decrease. The sensitivity of SEP components to halothane anaesthesia increased with peak latency: Cervical SEP remained relatively constant even during deep anaesthesia, early cortical potentials showed latency prolongation and amplitude reduction, middle and long latency components were progressively diminished with increasing halothane concentration. These changes have to be considered, when interpreting cervical and cortical SEP recorded intraoperatively.

Adolescent↗
PubMed1985

[Calcium antagonists in anesthesia. Additive analgesia using nimodipine in heart surgery].

Stress and pain induced by surgical trauma seem to be attenuated when calcium antagonists have been applied. In order to ascertain the effect of nimodipine, a new strong acting calcium channel blocker on plasma levels of various stress hormones twenty patients undergoing cardiovascular surgery where investigated in two groups. Ten patients received high-dose fentanyl anaesthesia (mean: 2,45 mg fentanyl/patient), whereas another ten patients were treated with 0,1 mg fentanyl/patient in addition to nimodipine 1,0 micrograms/kgbw X min (from onset of anaesthesia until start of extracorporeal circulation). Between the two groups were no significant differences with respect to perioperative course and postoperative demand for analgetics. Plasma levels of ACTH, somatotropin, glucose and free glycerol were markedly elevated in all patients (n = 20) intra- and postoperatively, whereas cortisol and prolactin remained unchanged. The present data suggest an additive analgesic effect of nimodipine during surgery. This phenomenon is possibly due to a blocking effect of calcium channel blockers on nociceptive nerves. The present model assumes that calcium is essential in pain perception and that decreased calcium would result in analgesia.

Analgesia↗
PubMed1985

[Experiences with "etomidate pro infusione" in heart surgery interventions with extracorporeal circulation].

The results of experimental studies with etomidate demonstrating positive hemodynamic effects as well as a decrease in intracranial pressure induced a study using etomidate during cardiac surgery. This randomized study including 506 patients should prove the influence of etomidate on the rate of psychic disturbances after cardiac surgery. Patients treated with etomidate received a loading dose of 1 mg/kg b.w. etomidate within 15 minutes followed by a continuous infusion of 1 mg/kg b.w./h until the end of ECC. Patients without etomidate were the control group. Psychic disturbances were observed in 25% of the control group and in 30% of the etomidate group. In both groups of patients there was a fair number of patients with perioperative cardiopulmonary problems (artificial ventilation longer than 24 hours; catecholamine therapy: epinephrine greater than 5 micrograms/min longer than 3 hours): 8% in the control group and 20% in the etomidate group. These results indicate that etomidate does not beneficially influence the rate of psychic disturbances after open-heart surgery; it may induce, however, cardiopulmonary side effects after cardiac surgery. The results of recent studies indicating drug induced adrenal insufficiency are discussed.

Adolescent↗
PubMed1984

The influence of anticoagulation on acid-base status and blood-gas analysis.

The results of acid-base status and blood-gas analysis can be influenced massively by incorrect sampling. We found that the addition of heparin has no great effect on blood-gas measurement. Citric acid and fluoride can also be admixed to blood samples in the usual concentrations without severe side-effects. The major error in the determination of blood gases and acid-base status is a consequence of even minimal dilution: filling the deadspace of a syringe with any diluent leads to unacceptable results. Hence, we conclude that blood specimens for determination of blood gases and acid-base status should be taken in specially prepared syringes containing the anticoagulant in the form of a dry substance. We think that citric acid is also acceptable for anticoagulation. Fluoride should be added in order to minimize alterations of pH due to anaerobic glycolysis.

Acid-Base Equilibrium↗
PubMed1984

[Hemodynamic effects in antagonism of neuromuscular blockage: atropine-pyridostigmine versus ipratropium bromide-pyridostigmine].

Antagonism of neuromuscular block using cholinesterase inhibitors and atropine is charged with several risks, which are at least partly caused by pharmacological characteristics of the anticholinergic drugs, e.g. short duration of action causing secondary bradycardia. Compared to atropine, ipratropium bromide, a new anticholinergic drug, is--due to its quarternary ammonium compound--characterized by longer duration of action. In contrast to atropine, this substance does not penetrate the blood-brain and placental barrier. Our present study was designed to compare the haemodynamic effects of both substances, using invasive monitoring, during antagonism of neuromuscular block with pyridostigmine. In contrast to atropine, ipratropium bromide induced a higher degree of initial tachycardia but did not allow secondary reduction of heart rate by rebound vagal stimulation. While cardiac output was almost constant, ipratropium bromide caused changes in stroke volume, which were due to alterations in heart rate. There were no clinically relevant changes of the other haemodynamic parameters. Cardiac arrhythmia were observed more often after administration of atropine and were of longer duration. In conclusion, ipratropium bromide is a useful alternative to atropine in patients with pre existing low heart rate and bradyarrhythmia.

Atropine↗
PubMed1984

[Plasma level of lidocaine following intraoperative bolus injection and infusion in heart failure].

In two groups of ten patients each (group I: myocardial insufficiency, group II: no myocardial insufficiency) during anaesthesia arterial plasma levels of lidocaine were studied, following iv bolus administration (1 mg./kg. bw) and subsequent lidocaine infusion (2 mg./min.) for 15 minutes. With this dosage, recommended for antiarrhythmic therapy, plasma levels exceeded the therapeutic range in group I and in some patients reached almost toxic levels (10 micrograms./ml.). In group II lidocaine plasma levels were within the therapeutic range (1,5-4 micrograms./ml.). In patients with myocardial insufficiency and/or reduced hepatic metabolism antiarrhythmic therapy with lidocaine has to be performed with significantly reduced dosages; drug monitoring is recommended.

Arrhythmias, Cardiac↗
PubMed1984

[Hemodynamics and changes in compliance of the extra-thoracic capacity system following administration of prostacyclin (PGI2)].

Hemodynamic effects of prostacyclin (PGI2) given as an intravenous infusion at a rate of 8 ng/kg/min were assessed in 50 patients with coronary artery disease at the time of aortocoronary bypass surgery. 1. During steady-state neuroleptic anesthesia, after sternotomy and pericardiotomy, before cannulation of the aorta and vena cava PGI2 led to the following changes: decreases in mean arterial pressure (-24%), total peripheral resistance (-46%), left ventricular pressure (-12%) and left ventricular end-diastolic pressure (-48%), increases in heart rate (+9%), cardiac output (+41%), stroke volume (+30%) and dp/dtmax (+26%) as well as nonsignificant decreases in right ventricular filling pressure (-13%) and mean pulmonary arterial pressure (-9%) together with an unaltered rate-pressure product. 2. In a randomized double-blind study PGI2 was infused throughout the period from two minutes prior to, until termination of extracorporeal circulation. The effects on compliance of the extrathoracic venous system were analyzed on the basis of changes in venous pressure and oxygenator volume. As compared with controls, patients receiving PGI2 were found to have a significant increase in compliance (.157 ml/mm Hg X kg). Thus, in this setting, PGI2 can affect marked vasodilatation with reductions in peripheral resistance and mean arterial pressure together with increases in cardiac output and heart rate.

Clinical Trials as Topic↗
PubMed1984

[Visual evoked potentials (VEP) in anesthesia and intensive care].

Methodological considerations and different stimulation techniques of visual evoked potentials (VEP) are described. VEP can provide information about neurological function during anaesthesia, surgery and in the unconscious patient after head injury. The feasibility of the method for intraoperative monitoring in neuro- and cardiac surgery and the influence of general anaesthetics and other contributing factors such as temperature, paCO2, pO2, part are discussed.

Anesthesia↗
PubMed1984

[Effect of postoperative parenteral feeding on protein metabolism in heart surgery patients. A comparative study].

To investigate the importance of amino acid infusions in immediate postoperative parenteral nutrition, cardiac patients were randomly allocated into two groups. Applicating identical carbohydrate calories (2000 kcal/day) group 1 received only essential amino acids while in group 2 a combined pattern of essential and non essential amino acids was infused. In addition to routine laboratory data several parameters of protein metabolism including nitrogen balance were evaluated. Although nitrogen balance was positive only in group 2 the differences between the two groups concerning other parameters measured were minimal. The different infusion regimes are discussed revealing the significance of additional parenteral nutrition in these patients.

Amino Acids↗
PubMed1984

[Diagnostic and prognostic significance of hemodynamic and respiratory parameters in venous air embolism].

In 25 patients undergoing neurosurgical operations in the sitting position we investigated the reliability of different continuously monitored haemodynamic and respiratory data for hypoxia, which is the most important alteration for the prognosis of air embolism. Simply referring to characteristic changes of end-tidal carbon dioxide (pCO2E) we were able to establish the diagnosis of venous air emboli in 12 of these patients. Besides a decrease in pCO2E, only the reduction of arterial oxygen concentration was statistically significant. Using a simple regression-test, however, no sufficient correlation between the two parameters could be found. Including pCO2E and haemodynamic data in our statistical comparison, multiple regression revealed an optimal correlation with the decrease in arterial pO2. Pathophysiological effects of air embolism are due to a transient accumulation of air in the pulmonary arterioles. Continuous monitoring of pCO2E is the most direct and therefore most reliable method for detection of pulmonary air emboli. Hypoxia, prognostically the most decisive alteration, develops parallel to the decrease in pCO2E and, being of multifactorial aetiology, is also influenced by haemodynamic effects of air embolism.

Carbon Dioxide↗
PubMed1984

[Sequential pacing following cardiopulmonary bypass].

Twenty patients with combined mitral valve disease were studied to evaluate whether the mode of cardiac pacing can influence myocardial performance after cardiopulmonary bypass. All patients underwent the same surgical procedure (mitral-valve-replacement) under standardized anaesthetic procedure. After weaning from extracorporeal circulation the following haemodynamic measurements were performed either under ventricular pacing or under sequential ("physiological") pacing: blood-pressure (radial artery), central venous pressure (CVP, jugular vein), cardiac output (as cardiac index, C. I.), pulmonary artery pressure (PAP) using Swan-Ganz-thermodilution catheter (jugular vein) and left atrial pressure (LAP). All patients were investigated as well under ventricular pacing as under sequential pacing (heart rate: 90 X min-1; AV-delay: 200 msec; stimulation with a pacemaker Medtronics 5330). Compared with the situation under ventricular pacing the haemodynamic parameters changed, when sequential pacing was applied: arterial pressure and cardiac output increased, whereas CVP as well as PAP and LAP decreased. The data indicate that there is some influence on cardiac work by the mode of pacing. Physiological pacing compared to ventricular pacing seems to lead to a marked improvement in cardiac performance. Particularly patients with severe dysrhythmia following cardiopulmonary bypass should be treated by physiological (sequential) pacing.

Blood Pressure↗
PubMed1984

[Long-term experiences with continuous peridural opiate analgesia with an implanted pump].

Continuous epidural opiate analgesia with an implantable, percutaneously refillable pump was induced in 6 patients with chronic pain of malignant origin. The efficacy of this method was compared with that of on-demand bolus-injections of epidural opiate. Side-effects and development of tolerance were not observed during a more than one year period of treatment. Increased daily doses for some days were only necessary in case of additional pain sources, e.g. induced by an intermediate operation. There were no hygienic problems (bacteriologic investigations) or problems due to technique of implantation (localisation of the implant, stability of the fixation, patency of the catheter). Examination of post mortem explanted pumps (determination of the flow rate, inspection for precipitation within the pump, testing of permeability of filters) and catheters (electron microscopy, testing of the material for surface conditions, tensile strength and elongation) as well as histological findings for local compatibility did not reveal adverse reactions after long-term treatment. Indications for this new method of pain treatment were established.

Aged↗
PubMed1984

[A case of anaphylactoid reaction following administration of etomidate].

After injection of etomidate during surgery for herniation of an intervertebral disk an anaphylactoid reaction occurred. Generalized erythema, severe urticaria, and rise in heart rate and blood pressure drop were observed. After treatment with an antihistaminic and a corticosteroid the phenomenons completely disappeared within 45 minutes.

Alcuronium↗
PubMed1984

[Plasma levels following lumbar epidural anesthesia with 0.75% bupivacaine].

In ten patients undergoing total hip replacement, plasma levels of bupivacaine were studied, following lumbar epidural administration, with special reference to the early phase. In contrast to previous studies concerning the 0.5% solution, we found an early rise between 3 and 5 min, which was nearly identical with the peak level. The maximum concentration was 2.76 micrograms/ml and within the estimated safety margin. The necessity of preventing acidosis and hypoxia is pointed out when using bupivacaine 0.75%.

Acidosis, Respiratory↗