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Biomedical subjects

G Hempelmann

Publications and source records attributed to G Hempelmann.

At least 469 records · Page 26Linked to original sources
PubMed1986

[Isolated modification of the vascular system by vasopressor agents (akrinor, etilefrin, ephedrine, norfenefrine, amezinium) during extracorporeal circulation in man].

The influence of different vasopressors (Akrinor, etilefrine, ephedrine, norfenefrine, ameziniummetilsulfate) on arterial perfusion pressure and oxygenator volume during extracorporeal circulation was compared to a control group. All substances led to an increase in perfusion pressure, thus demonstrating a direct influence on arterial vessels. The rise in arterial pressure after injection of ameziniummetilsulfate persisted during the investigation period, whereas norfenefrine led to a short-lasting, but massive increase. No rise in venous tone was noticed during the investigation period.

2-Hydroxyphenethylamine↗
PubMed1986

[Spasticity treatment with spinal morphine or midazolam. In vitro experiments, animal studies and clinical studies on compatibility and effectiveness].

Recent pharmacological investigations have support the hypothesis that spinal modulation of nociception as well as motor coordination is related to the activity of spinal interneurons and that certain spinal transmitters are involved in the control of both regulatory systems. Opioids and benzodiazepines, i.e. endorphin- or GABA-induced mechanisms, may be of importance for spinal treatment of spasticity in the near future. In order to clinically evaluate the interactions of these spinal processes we performed in vitro-experiments, animal studies and clinical investigations on the compatibility and antispastic efficacy of spinally administered opiates and benzodiazepines. Preclinical studies on tissue- and CSF-tolerance of different benzodiazepines (pH, tonometry, turbidimetry, histological findings in animals) are in favour of midazolam, a water-soluble compound, which is active against pharmacologically induced spasms in animals (strychnine application in cats with chronical catheterization of the subarachnoid space) after lumbar intrathecal injection. Using an appropriate dosage of intrathecal midazolam selective blockade of spasticity of the hind legs may be demonstrated with integrated EMG. Clinical investigations (neurological assessment using rating scores for spasticity) in 16 patients, including a double-blind comparison of epidural morphine or midazolam, indicate that both drugs are effective against spinal spasticity of different origin. Efficacy of spinally applied agents depends on the severity of spasms and on the duration and extent of systemic pretreatment.

Animals↗
PubMed1986

[Changes in lymphocyte subpopulations in relation to anesthesia procedure].

44 patients undergoing comparable gynaecological operations received either halothane- modified neuroleptanaesthesia or a combination of epidural and NLA. Monoclonal antibodies were used to determine 8 different lymphocyte subpopulations in blood samples drawn before and after anaesthesia and on the first postoperative day. Cell populations were counted by fluorescent microscopy. Halothane anaesthesia produced both a depression of T-cells (72.67% preoperatively to 52.79% postoperatively) and of the helper/suppressor ratio (1.46 to 1.10); meanwhile activated T-cells increased from 2.33% to 6.83%. After neuroleptanaesthesia as well as after halothane the HLA-DR positive cells decreased (21.05% to 19.29%; 25.22% to 20.29%). The B-cell fraction was elevated from 2.33% to 6.83% following combined anaesthesia. The potential of the anaesthetics to produce subsequent alterations in host defense is discussed.

Adult↗
PubMed1986

[Intra- and postoperative interactions between the 2 opioids fentanyl and buprenorphine].

In order to demonstrate pharmacokinetic and pharmacodynamic interactions between fentanyl and buprenorphine, 3 groups of patients (n = 30) were compared, receiving either fentanyl (0.005 mg/kg b.w.) or buprenorphine (0.01 mg/kg b.w.) or both opioids as analgesic during surgery for disc protrusion. For a period of 4 h haemodynamic parameters were monitored and blood samples were taken for determination of the following concentrations: ADH, ACTH, cortisol, glucose, unbound glycerol, fentanyl and buprenorphine. Blood gas analyses were performed up to 2 h postoperatively. Although in all groups haemodynamic parameters were constant, there was an increase in factors related to operative stress (cortisol, glucose, unbound glycerol, postoperative acidosis) after the combination of both opioids, while postoperative ventilatory parameters in this group were not improved by the partial agonist buprenorphine. Plasma levels were not affected by combined application, except for a slight elevation of buprenorphine concentrations during additional use of fentanyl. Buprenorphine, at least in higher dosages, seems to antagonize analgesia induced by fentanyl, although respiratory depression is even more pronounced. It may be assumed, that with partial agonists the relation of agonistic and antagonistic activity may be different, depending on the dosage used and on the respective pharmacologic effect observed during investigation.

Acid-Base Equilibrium↗
PubMed1986

[Airway pressure and transcutaneous O2 and CO2 partial pressure as monitoring measurements for high-frequency jet ventilation?].

Two different methods of measuring airway pressures (n = 7), and the usefulness of transcutaneous pO2 and pCO2 measurement (n = 9) in monitoring High Frequency Jet Ventilation (HFJV), were investigated in critically ill patients. Airway pressures obtained by tip manometer from different points within trachea and mainstem bronchi during HFJV (f = 100/min, inspiratory time 40%, FIO2 0,4, minute volume 25.6 +/- 5.2 l) were nearly identical with pressures obtained from the integrated pressure line of HI-LO-JET endotracheal tubes (R = 0.9638). There was no difference between proximal and peripheral airway pressures. When using a PEEP-valve, rather high values of PEEP may occur due to gas trapping. There was sufficient correlation between transcutaneous and arterial pO2 (R = 0.7573) and poor correlation between transcutaneous and arterial pCO2 (R = 0.4987). paO2 values were 51.1% above, paCO2 values 33.4% below transcutaneous values. Transcutaneous measurement of pO2 and pCO2 is only an additional method in monitoring HFJV which can reveal rough trends but cannot replace blood gas analysis.

Adult↗
PubMed1986

[High frequency jet ventilation as a form of artificial respiration in thoracic and abdominal surgery. Clinical experiences].

A total of 66 patients undergoing thoracic and abdominal surgery were ventilated with high-frequency jet ventilation (HFJV), using frequencies of 100 cycles/min (n = 33), 150 cycles/min (n = 21), and 200 cycles/min (n = 12). Inspiratory time was 30% and FIO2 0.4 (abdominal) and 0.5 (thoracic) respectively. Normocarbia required minute-volumes of 215.0 +/- 47.4 ml/kg (100 cycles/min), 256.0 +/- 39.2 ml/kg (150 cycles/min), and 298.0 +/- 41.0 ml/kg (200 cycles/min) respectively. With HFJV paO2-values were significantly below those under conventional ventilation (118.5 mmHg versus 153.2 mmHg; 137.5 mmHg versus 165.5 mmHg; 136.4 mmHg versus 156.7 mmHg). Heart rate, arterial blood pressure, and central venous pressure showed no differences. With HFJV 8 patients revealed paO2-values below 80 mmHg, 3 patients had to be returned to conventional ventilation because of severe hypoxia. HFJV is considered of no advantage over conventional ventilation and may cause prodigious hypoxia in patients with pulmonary dysfunction. Therefore, HFJV cannot be recommended in thoracic and abdominal surgery.

Abdomen↗
PubMed1986

[The relation between risk factors and mortality in aortocoronary bypass operations].

Risk factors related to increased mortality were determined on the basis of 329 aortocoronary bypass operations. They were: (1) emergency surgery, (2) poor left ventricular function, (3) reoperation, and (4) pulmonary hypertension. Angina pectoris, recent myocardial infarction, age over 65 years, obesity, significant systemic disturbances, smoking, arterial hypertension, and sex were without effect.

Age Factors↗
PubMed1986

[Effect of glucocorticoids on extravascular lung water following extra-corporeal circulation].

The influence of 3 different, preoperatively given glucocorticoids (30 mg/kg bw methylprednisolone, 3 mg/kg bw dexamethasone, 30 mg/kg hydrocortisone) on extravascular lung water (EVLW) was investigated in a randomised study consisting of 60 patients undergoing elective aortocoronary bypass surgery and compared to a control group having received 0.9% NaCl as placebo. EVLW-measurements were performed by using the double indicator dilution technique with indocyanine green and a microprocessed lung water computer. Besides EVLW-measurements haemodynamics and various laboratory data were studied before as well as after (15 min, 45 min, 5 h) extracorporeal circulation (ECC). ECC was followed by an increase in EVLW, which was less pronounced in the dexamethasone-group without being statistically significant (p = 0.1), however. Pulmonary gas exchange, too, did not differ statistically, in spite of a less pronounced (p = 0.1) deterioration of paO2 in the dexamethasone-group. Haemodynamics and laboratory data in the corticoid-group did not show any significant difference compared to the non-treated control group. It was concluded, that pretreatment with corticoids in pharmacological doses in cardiac surgery had no beneficial effects on extravascular lung water and pulmonary function.

Capillary Permeability↗
PubMed1986

[Hemodynamic effects in high-dose infusion of nimodipine, a new calcium antagonist].

Nimodipine, a new calcium channel blocker, seems to be effective in the treatment of vasospasm in cerebral vasculature. Typical cardiovascular side effects have limited the dose in neurology and neurosurgery to 0.03 mg/kg X h. This study was designed to examine the influence of an infusion of high dose nimodipine (0.09 mg/kg X h) on haemodynamics. 52 patients undergoing aorto-coronary bypass surgery and prospectively randomised in a nimodipine group and a control group having received 0.9% saline solution as placebo were investigated at 3 different times: 1. before induction of anaesthesia (n = 6) 2. during anaesthesia (n = 10) 3. during extracorporeal circulation (ECC n = 10). Predominant effect of high-dose nimodipine was a decrease in total systemic resistance (TSR), followed by a decrease in mean arterial pressure (MAP) and a significant increase in cardiac output. Haemodynamic effects were much more pronounced during anaesthesia in comparison to patients before induction of anaesthesia, thus demonstrating an interaction between anaesthetics and calcium channel blocker. Heart rate (HR -9.3%) and dp/dtmax (-17%) showed a decrease, too. The decrease in MAP and HR in connection with a decrease in left ventricular pressure (-21.9%) and left ventricular end diastolic pressure (-42.8%) indicate a reduction in myocardial oxygen demand. An increasing dosage of nimodipine is accompanied by increasing cardiovascular effects. From the haemodynamic point of view high dosage of nimodipine seems to be of advantage in patients with hypertension and/or coronary heart disease suffering simultaneously from cerebral vasospasm.

Coronary Artery Bypass↗
PubMed1986

New membrane oxygenator (LPM 50): influence on extravascular lung water and pulmonary function in comparison to bubble oxygenator.

A prospective, randomized, clinical study involving 30 patients undergoing aorta-coronary bypass grafting was designed to compare the influence of a new membrane oxygenator and a commonly used bubble oxygenator on extravascular lung water and pulmonary function after extracorporeal circulation. Although membrane oxygenators might have some advantages from the biochemical and biophysical points of view, in this clinical study no differences in lung water accumulation and pulmonary gas exchange could be detected between bubble and membrane oxygenators after extracorporeal circulation.

Body Water↗
PubMed1986

[Hemodynamic findings using high-frequency jet ventilation in major surgery].

13 patients with normal lung function undergoing isolated hyperthermic cytostatic perfusion were submitted to high-frequency jet ventilation (HFJV; f = 150/min, inspiratory time 30%, FIO2 0.4) and conventional ventilation (CV; f = 12/min, PEEP + 4 cm H2O) respectively. Normoventilation required a minute ventilation of 6.4 +/- 1.1 l/min (paCO2 35.4 +/- 3.3 mmHg) with CV and 15.9 +/- 2.2 1/min (paCO2 39.0 +/- 4.3 mmHg) with HFJV. Mean airway pressure was significantly lower with HFJV (4.8 +/- 1.1 cm H2O) compared to CV (7.5 +/- 1.5 cm H2O). Arterial oxygenation, heart rate, pressures and resistances of systemic and pulmonary circulation, cardiac work and stroke indices, intrapulmonary shunting, and oxygen consumption showed equal values with both modes of ventilation. HFJV does not have any striking advantage over CV and therefore cannot be recommended for routine anaesthesia in abdominal surgery.

Abdomen↗
PubMed1986

[Acute normovolemic hemodilution in extensive surgical interventions].

In order to ascertain the effect of acute isovolaemic haemodilution on haemodynamics and various laboratory parameters as well as homologous blood consumption 44 patients undergoing major liver surgery were investigated in two groups: group I (n = 22) underwent acute normovolaemic haemodilution after induction of anaesthesia; group II (n = 22) had no blood withdrawn and served as control. Haemodilution led to typical haemodynamic effects such as increase in cardiac index and decrease in systemic as well as pulmonary vascular resistance; no detrimental effect of the procedure could be observed. Haemodilution led to a marked reduction in the consumption of banked blood which was on the average 1.8 units/patient against control intraoperatively and 3.1 units/patient postoperatively summing up to a total of 4.9 units/patient.

Adult↗
PubMed1986

[High frequency jet ventilation in patients with acute respiratory failure. A comparison with conventional artificial respiration].

The major advantage of High Frequency Jet Ventilation (HFJV) in the treatment of patients with ARDS was commonly seen in better oxygenation and lower airway pressures, compared to conventional ventilation. Furthermore, HFJV seemed to be successful even in those patients in whom conventional ventilation had failed. We compared HFJV (f = 100/min, inspiratory time 40% to 50%) to conventional ventilation (f = 10/min, PEEP 5 to 10 cm H2O). For mean airway pressure and FIO2 equal values were chosen in both ventilatory modes. With HFJV paO2 was significantly (P less than 0.01) lower (82.2 +/- 28.2 mmHg compared to 139.2 +/- 23.5 mmHg), intrapulmonary shunting higher (29.2 +/- 19.6% compared to 15.3 +/- 6.4%) than with CV. Ventilatory volume required for normocarbia under HFJV was 25.6 +/- 5.4 l/min approximately equal to 341 +/- 81.8 ml/kg B.W. Pulmonary artery pressure (PAP 25.0 +/- 5.0 mmHg compared to 19.9 +/- 4.7 mmHg), central venous pressure (10.5 +/- 4.2 mmHg compared to 8.8 +/- 3.0 mmHg), pulmonary capillary pressure (13.3 +/- 4.4 mmHg compared to 11.3 +/- 3.7 mmHg), pulmonary vascular resistance (131.4 +/- 55.0 dyn . s . cm-5 compared to 96.7 +/- 33.7 dyn . s . cm-5) and right cardiac work index (1.38 +/- 0.55 kg . m/m2 compared to 1.05 +/- 0.33 kg . m/m2) were significantly increased (P less than 0.01) under HFJV. The other haemodynamic variables showed no difference between the two ventilatory modes. HFJV was inferior to conventional artificial ventilation in all patients and caused severe hypoxia in several patients, leading to pulmonary vasoconstriction and increased work of the right heart.(ABSTRACT TRUNCATED AT 250 WORDS)

Critical Care↗
PubMed1986

[Hemodynamic effects of nisoldipine (Bay k 5552), a calcium antagonist, in coronary surgery patients].

The hemodynamic effects of the intravenous application of nisoldipine (0.2 microgram/kg bw per minute and 0.1 microgram/kg bw per minute) were studied in 70 patients with coronary artery disease. Measurements were performed before the induction of anesthesia, during anesthesia (prior to the cannulation of the great vessels) and 5 min after the end of extracorporeal circulation (ECC) (with the same preload as before ECC) as well as during ECC. Each group was compared to a group of patients who received a placebo injection. The preoperative and intraoperative application of nisoldipine produced a decrease in the mean arterial pressure and total systemic resistance, whereas the cardiac index and the stroke-volume index increased. Only during preoperative measurement did the heart-rate increase. The central venous pressure, pulmonary artery pressure and pulmonary capillary wedge pressure remained unchanged. There was no change in the dp/dtmax after 0.2 microgram/kg bw per minute of nisoldipine. There was no difference in hemodynamic outcome between the three groups 5 min after the end of ECC. During ECC, nisoldipine did not reduce the vascular resistance, possibly because of the hypothermic conditions. The principal effect of nisoldipine is to increase the cardiac index by decreasing the total systemic resistance without influencing the myocardial contractility.

Calcium Channel Blockers↗
PubMed1986

[H-H-H syndrome: a rare disease also relevant in anesthesiology].

We report on a 17-year-old boy with H-H-H-syndrome (hyperornithinaemia, hyperammonaemia, homocitrullinuresis), an inborn disorder of the urea cycle, who had to undergo osteo-synthesis of a fractured upper leg. Pathophysiological aspects of this rare syndrome as well as possible recommendations for the anaesthesiological management are discussed.

Adolescent↗
PubMed1986

[The pharmacokinetics of continuous peridural morphine infusion].

In patients with cancer pain treated by continuous epidural opiate infusion (4.5-24 mg morphine per day) via implanted or portable pumps (n = 40) plasma levels of morphine were determined during the postoperative period and during regular refill of the pump systems. Concentrations were between 2.6 and 18.8 ng/ml depending on daily dosage and body weight. There were no signs of accumulation. Concentrations in lumbar CSF measured in some of the patients were 15-20 higher but decreased by 10-20% (in relation to daily dosage) in the course of long-term treatment. This may be induced by reduction in permeability of the dura due to fibrosis within the epidural space after chronicle catheterization. Cervical CSF concentrations (during chordotomy) were about 1/6 to 1/7 of the corresponding lumbar CSF levels. It may be assumed that epidural opiate infusion in spite of low blood levels is accompanied by relevant cerebral opiate actions.

Epidural Space↗
PubMed1986

[Somatosensory evoked potentials under thiopental and etomidate].

The somatosensory evoked potential in response to median nerve stimulation was recorded in 42 patients during infusion of either 15 mg/kgbw thiopentone (TH) or 1 mg/kgbw etomidate (E) within 15 min and before and after injection of 0.3 mg/kgbw etomidate bolus. Cortical and cervical responses were analysed simultaneously and central conduction time (CCT) was calculated. Marked alterations of waveforms and an increase in latency of the primary cortical SEP and of CCT were observed in all patients. Infusion of TH or E was followed by a diminution of middle and long latency components. Amplitude of the cortical N20 was found to be unchanged during and after TH and to be increased after infusion or injection of E, indicating the synchronizing properties of this drug. The cervical SEP (N14) remained entirely unchanged in response to both agents. During hypnotic drug administration a pronounced increase in latencies and CCT as well as a decrease in the number of identifiable peaks has to be considered when SEP monitoring is performed intraoperatively or in intensive care treatment.

Anesthesia↗