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Biomedical subjects

R Dennhardt

Publications and source records attributed to R Dennhardt.

At least 37 records · Page 2Linked to original sources
PubMed1985

[Bupivacaine 0.5% CO2 in spinal anesthesia].

The clinical usage of 0.5% bupivacaine-CO2 for spinal anaesthesia was tested in 45 patients. The use of bupivacaine CO2 is safe, segmental dificits were not observed. Compared to bupivacaine-HCl the latency period is shorter (7.7 min), whereas the duration of maximal analgesic spread (105 +/- 31 min) is identical. 93% of the patients had a complete motor blockade. The solubility of bupivacaine-CO2 in CSF (1.75 mg ml-1) is more than double the solubility of bupivacaine-HCl (0.8 mg ml-1), thus lowering the risk of precipitation.

Anesthesia, Spinal↗
PubMed1985

[Toxic methemoglobinemia following the postoperative ingestion of 4,4-diaminodiphenylsulfone (DADPS)--on the differential diagnosis of cyanosis].

Blood gas analysis devices routinely used in clinical practice measure pH, pCO2 and pO2 directly, while all other values they specify are calculated on the basis of nomograms. In the presence of higher concentrations of biologically useless forms of haemoglobin, calculation of the haemoglobin saturation (% O2 Hb) leads to a clinically relevant false assessment of oxygen availability. A case is described in which toxic methemoglobinaemia occurred postoperatively after resumption of long-term medication with 150 mg 4,4-diaminodiphenylsulfone (DADPS). Increasing methaemoglobin values up to maximal 17.7% at a total haemoglobin of 11.3 g/dl correlated with the symptoms of cyanosis and respiratory distress. This symptom complex, which is not atypical postoperatively, could not be clarified by differential diagnosis with the aid of cardiac output measurements and arterial blood gas analyses. The cardiac index amounted to 4.1 l/m2 at a pulmonary capillary wedge pressure of 8 mmHg; the arterial partial oxygen pressure was between 16 and 19 kPa. Only the differential determination of oxihaemoglobin, CO-haemoglobin and methaemoglobin with an oximeter yielded evidence of severe arterial hypoxaemia and made therapy possible.

Adult↗
PubMed1985

The effect of dopamine on muscle PO2 in healthy volunteers and intensive care patients.

The effect of systemic dopamine administration (2-10 micrograms kg-1 min-1) on the Po2 distribution (histograms) and the mean Po2 in the m. vastus lateralis of m. quadriceps femoris in nine healthy volunteers and seven critically ill patients has been studied with a newly developed bedside measuring procedure. Dopamine initially raised mean muscular Po2 in both groups. In the volunteers, mean muscular Po2 thereafter decreased gradually but still remained slightly elevated after 30 min of dopamine infusion. This increase in muscle oxygenation could be abolished by the administration of a dopamine antagonist (metoclopramide). In the patients, the initial dopamine-induced increase of Po2 was significantly slower and reached a plateau within 30 min. The results are discussed with special attention given to the data available on the action of dopamine on given peripheral circulation.

Critical Care↗
PubMed1984

[Respiratory controlled intermittent inspiratory pleural drainage--a method for handling life threatening bronchopleural fistulas].

A report is presented on a technical device for artificial ventilation of patients with severe bronchopleural fistulae. The respirator-controlled apparatus interrupts drainage suction at the beginning of inspiration and releases it again at expiration. In contrast to similar constructions, this system does not allow drainage secretions to influence its functional efficiency. Modifications for connection of this apparatus are conceivable for all modern respirators. A case is described in order to demonstrate the effectiveness of the procedure. The hitherto published literature is critically reviewed.

Adult↗
PubMed1983

[Respiratory and sleep-inducing effects of i.m. midazolam as premedication for regional anesthesia. Comparison with diazepam, promethazine/pethidine and placebo].

The effects of respiratory depression and sleep induction produced by 0.1 mg/kg and 0.15 mg/kg of midazolam i.m. were examined in patients in whom urological interventions had to be performed under spinal anesthesia. The same parameters were evaluated for 0.2 mg/kg of diazepam i.m. as well as 50 mg/50 mg of pethidine/promethazine i.m. and placebo i.m. The major difference between 0.1 mg and 0.15 mg/kg body weight of midazolam was a more pronounced PCO2-increase in the group with the higher dosage. Both dosages led to anterograde amnesia in 8 or 9 of 10 patients respectively. No amnesia developed in the control groups. Respiratory depression and sleep induction occurred later with promethazine/pethidine (at 60 min) or diazepam (at 120 min) than with midazolam. Noteworthy in the Diazepam and placebo group was a hyperventilation lasting 60 and 120 min respectively. The arterial PO2 decreased in all groups during the intervention. Under midazolam, the decrease was significantly higher statistically than in the control groups during the first 60 min at both dosages. Premedication with 0.1 mg/kg i.m. of midazolam proved to be sufficient in all patients. The rapid onset of action, the sleep during the intervention and the amnesia associated with it suggest that this form of premedication is more favorable than the other procedures examined. The dosage of 0.15 mg/kg of midazolam proved to be too high: in addition to producing a stronger respiratory depression, it had the effect of rendering cooperation with some patients more difficult.

Aged↗
PubMed1983

[Blood and cerebrospinal fluid levels of bupivacaine in spinal anesthesia].

Blood and liquor concentrations of bupivacaine were followed in 20 patients after spinal injection of 15 mg bupivacaine-HCl or bupivacaine-CO2; determination of the local anaesthetic was done by gas chromatography. Whole-blood concentrations of bupivacaine for both formulations lay between 0.2 and 0.3 microgram/ml. Two min after intrathecal administration of 15 mg bupivacaine, liquor concentrations averaged around 600 micrograms/ml, i.e., the precipitation threshold was not reached. Concentrations of individual patients, however, indicated that considerably higher concentrations can be attained; the possible reasons are discussed. Bupivacaine-CO2 represents a suitable preparation for spinal anesthesia, which, particularly with regard to blood levels, shows no disadvantages compared to bupivacaine-HCl.

Adult↗
PubMed1983

[Effect of neuroleptanalgesia on operation-induced rise in the antidiuretic hormone].

Plasma-levels of antidiuretic hormone were measured in patients undergoing major abdominal surgery pre-, intra- and postoperatively. All patients (n=20) received neuroleptanalgesia as anaesthetic procedure; 10 of them received etomidate additionally. Initial value of vasopressin as well as values after induction of anaesthesia stayed within normal range in all patients. The operation period was accompanied by elevated ADH-levels with a maximum of 500% above initial values. 5 patients having been antagonized postoperatively with naloxone 0.005 mg/kgbw showed marked increase in ADH-level. In comparison to former investigations we conclude that NLA can not block stress-induced rise in vasopressin-concentration effectively as seen under the combination of NLA plus epidural analgesia.

Abdomen↗
PubMed1983

Influence of epidural fentanyl on stress-induced elevation of plasma vasopressin (ADH) after surgery.

The role of techniques used for management of intra- and postoperative pain on plasma levels of antidiuretic hormone (ADH) was evaluated in 107 patients undergoing abdominal or thoracic surgery. Fifty-one patients had neurolept-anesthesia (NLA) intraoperatively followed by intramuscular piritramide, a long-lasting synthetic narcotic, for relief of postoperative pain. Fifty-six patients had a combination of epidural bupivacaine and NLA intraoperatively followed by epidural fentanyl for relief of postoperative pain. All patients had daily measurements of serum levels of potassium and sodium, plasma levels of ADH, and plasma osmolality for the first 5 postoperative days. In 67 patients arterial blood-gas tensions also were measured at similar times. There were no significant changes in serum electrolyte levels, plasma osmolality, or blood-gas tensions intra- or postoperatively. Plasma ADH levels increased postoperatively in all patients, but in patients given NLA followed by postoperative intramuscular narcotics, plasma levels of ADH were more than twice as great as in patients given epidural anesthesia followed by epidural fentanyl.

Adult↗
PubMed1983

[Anesthesia procedure and postoperative ADH secretion].

44 patients undergoing major abdominal and thoracic surgery received different anaesthetic treatment and different pain therapy during the postoperative period (4 groups). Analysis of plasma vasopressin was performed in all patients pre-, intra- and five days postoperatively. In two groups of patients under neuroleptanalgesia (group A and B) ADH-levels increased markedly during the operation procedure, whereas those of patients under NLA plus epidural analgesia with bupivacaine 0.5% (group C and D) showed only a slight increase intraoperatively. During the postoperative period pain relief was provided by giving fentanyl epidurally (group B and D) or with systemic administration of piritramide (group A and C). During the investigation period vasopressin secretion in patients under epidural opiate therapy was significantly less pronounced as in patients under systemic opiate therapy.

Analgesia↗
PubMed1982

Exteriorized lymphatico-venous shunts in conscious rats.

Surgical techniques for establishing fistulas of the hepatic and intestinal lymphatics and thoracic duct in conscious rats are described. Continuous recirculation of the lymph into the vena cava inferior is performed by a device which measures flow velocity before returning the lymph to the animal through a permanent venous catheter. Clotting is prevented in all cases by constant infusion of an anticoagulant solution (containing heparin or Na-citrate) into the top of the indwelling catheter.

Animals↗
PubMed1982

[Variations in vasopressin (ADH)-levels during NLA combined with epidural fentanyl-analgesia (author's transl)].

10 patients scheduled for thoracic, abdominal or vascular surgery received anaesthesia as a combination of neuroleptanalgesia plus epidural opiate-analgesia. Antidiuretic hormone levels (ADH), serum-electrolytes (Na+, K+) and plasma osmolality have been investigated preoperatively (twice), intraoperatively (six times), during the first postoperative day (three times) and for five days postoperatively (once a day). There was a significant increase in ADH in all patients intra- and postoperatively, whereas serum-electrolytes and plasma-osmolality stayed within normal range. Maximum ADH-values were measured during the intraoperative period, postoperatively ADH-levels reached the normal range after 5 days. This increase in plasma-ADH-levels was not accompanied by typical haemodynamic changes. From the aspect of metabolic endocrine response to surgery, our results indicate no advantage of the combination of neurolept-analgesia plus epidural opiate-analgesia for the intraoperative period.

Aged↗
PubMed1981

[The effect of desoxycholate on the electrolyte and water absorption in the terminal ileum. Studies in conscious rats (author's transl)].

With an in vivo perfusion technique the influence of 10(-3) mol/l desoxycholate (DC) on the net electrolyte and volume absorption are studied in the terminal ileum of unanesthetized rats. Control experiments are performed in the same animal. The following data are observed: 1. There is a highly significant decrease in net Cl- absorption (p less than 0.002). 2. The Na+ and volume absorption is diminished or reversed into secretion. 3. The K+ secretion is enhanced (P less than 0.01). The sodium-water equivalent is reduced caused by alteration of the Na+ as well as the water permeability.

Animals↗
PubMed1981

[Continuous measurement of cations in the blood-stream of patients (author's transl)].

An electrochemical flow-through system in the blood-stream of patients is described, which allows continuous measuring of Na+-, K+- and Ca++-concentrations. The ion-selective electrodes show excellent selectivity constants. Activity potentials of greater than 97% of the theoretical measurement characteristics of the electrodes (Nernst-factor) could be achieved. This electrochemical measuring device makes it possible to measure continuously the electrolyte activities in the blood. Results of direct patient measurements are demonstrated.

Calcium↗
PubMed1981

[Plasma antidiuretic hormone level as an indicator of perioperative stress (Part I) (author's transl)].

The secretion of antidiuretic hormone (ADH) is mainly influenced by changes in osmolality and blood volume. In addition stress and surgical trauma may cause an elevation in plasma-ADH levels. In 20 patients scheduled for similar surgical procedures two different anaesthesia techniques were applied: in group 1 (n = 10) a combination of peridural anaesthesia and neuroleptanalgesia (PDA/NLA) was performed, in group 2 halothane anaesthesia with intubation was used. The perioperative control of plasma-ADH levels demonstrated a smaller increase in group 1 (PDA/NLA) compared to group 2 (Halothane), thus implicating a better attenuation of stress and pain.

Adolescent↗
PubMed1981

[Plasma-antidiuretic hormone level as indicator of postoperative stress (part II) (author's transl)].

For a period of five days serum levels of antidiuretic hormone (ADH) have been investigated postoperatively in a group of 20 patients with upper abdominal surgery. In addition serum electrolytes (Na+, K+) and plasma osmolality have been controlled regularly. Patients in group A (n = 10) received Fentanyl epidurally (0.1-0.2 mg diluted with 0.9% saline solution) for treatment of postoperative pain, whereas in group B (n = 10) systemic opiate therapy was performed by intramuscular application of piritramide (Dipidolor, 15-25 mg). There was a significant increase in ADH in all patients, whereas serum electrolytes (Na+, K+) and plasma osmolality stayed within normal range. ADH-levels in group A (epidural opiate), however, were significantly lower than mean values in group B (systemic opiate application). The postoperative increase in ADH is interpreted as a reaction to stress and trauma, being less pronounced, when epidural opiate therapy is performed for postoperative pain treatment.

Adult↗
PubMed1980

[Regulatory mechanisms in the liver during enteral administration of hypotonic and hypertonic solutions. Studies in the waking rat].

The mechanisms of homeostatic regulation of the liver after enteral application of hypotonic and hypertonic fluids are studied. The experiments are carried out in unanaesthetized rats with indwelling catheters in aorta, vena portae and duodenum. A new technique of cannulating the vena hepatica in the rat is described. In this way the hepatic electrolyte clearance can be calculated. As can be estimated from the results, the liver functions as the main osmotic buffers between the enteral and the parenteral compartment. This is realized by absorption or secretion of water or electrolytes from the portal venous blood. The capacity of this homeostatic mechanism of the liver is influenced by the state of hydration of the animal.

Animals↗
PubMed1980

[The solubility of bupivacaine in cerebrospinal fluid (author's transl)].

The precipitation of different local anaesthetics was studied spectrophotometrically in vitro. Bupivacaine-HCl precipitates at a pH of 7.4 of the cerebrospinal fluid when the concentration is 0.75 mg/ml. The bupivacaine-solution with admixture of epinephrine is not associated with turbidity up to 2.5 mg/ml. The CO2-preparation of bupivacaine shows no decrease of extinction. Mepivacaine, lidocaine and carticaine do not precipitate at the range of CSF-pH from 6.9 up to 9.0. The relevance for clinical use is discussed. After intrathecal application of less than 15 mg bupivacaine-HCl of a 0.5% solution, no precipitation will occur. Since the volume of distribution in the subarachnoidal space is lowered after application of hyperbaric local anaesthetic solutions, the possibilities of precipitation are enhanced.

Adolescent↗