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Biomedical subjects

C Diefenbach

Publications and source records attributed to C Diefenbach.

At least 55 records · Page 3Linked to original sources
PubMed1995

The importance of colloid osmotic pressure measurements to prevent oncotic overdosage during cardiac surgery.

OBJECTIVE: Colloidal infusion therapy during cardiac surgery has changed from the principal use of human albumin to the preference for synthetic colloids. Despite the possible interference of synthetic plasma expanders with the biuret determination of total plasma protein (TPP), perioperative infusion therapy is frequently directed on the basis of TPP and albumin levels. The hypothesis that the level of TPP or albumin does not reflect the plasma colloid osmotic pressure (COP) if synthetic plasma expanders are used was studied. MATERIALS AND METHODS: In 61 patients undergoing elective cardiac surgery the course of COP and its correlation to the TPP and albumin levels were investigated. Natural and artificial colloids were used for colloidal infusion therapy. RESULTS: No correlation between TPP/albumin levels and COP was found preoperatively and on arrival at the ICU, only a weak correlation was observed at 24 hours and 48 hours postoperatively. The wide range of the confidential interval indicates that the COP cannot be estimated correctly neither from the TPP nor the albumin level. The postoperative COP was significantly increased compared to the preoperative levels indicating oncotic overdosage. CONCLUSIONS: In order to avoid oncotic disturbances, indication for colloidal volume replacement during cardiac surgery should be controlled by oncometry if natural and synthetic colloids are administered.

Blood Proteins↗
PubMed1994

Simple and rapid high-performance liquid chromatography method for the determination of alcuronium in human plasma and urine.

A simple and quick HPLC assay for alcuronium is presented. Its characteristics are: precipitation of plasma proteins by acetonitrile; Spherisorb 5-CN column; acetonitrile-water (46:54, v/v) as mobile phase; flow-rate 1 ml/min; laudanosine 0.06 mg/l as internal standard with plasma; external standard with urine; UV detection at 294 nm; retention time 5.4 min; detection limit 0.025 mg/l; documented linearity: 0.025-2.0 mg/l for plasma and 1.0-80 mg/l for urine; intra- and inter-assay variability below 4%. None of nine drugs used in perioperative pharmacotherapy interfered with the assay. Satisfactory performance was exemplified in a 12-h pharmacokinetic evaluation of two patients.

Alcuronium↗
PubMed1994

[Muscle relaxation in patients with neuromuscular diseases].

The classification of neuromuscular diseases with regard to the use of muscle relaxants is based on the localisation of the particular abnormality. Three types of syndromes can be differentiated: (1) denervation states; (2) disturbances of neuromuscular transmission; and (3) intracellular disease. Succinylcholine should be avoided in all types of denervation syndrome due to the possibility of life-threatening hyperkalaemia. The time frame during which succinylcholine must be avoided following a traumatic denervation or burn begins 24 h after the event. The exact period of risk is unknown, but a duration of 6 months can be considered the absolute minimum. Patients may display increased sensitivity to non-depolarising muscle relaxants following damage to the second motoneuron (e.g., amyotrophic lateral sclerosis), whereas in diseases of the first motoneuron (e.g., cerebral apoplexy), increased resistance to muscle relaxants may be observed in the affected parts of the body. In diseases of the neuromuscular junction (myasthenia gravis) there is increased sensitivity to non-depolarising muscle relaxants. No complications have been described following the use of succinylcholine in these patients, however, the use of reversal agents may lead to prolongation of the effect of succinylcholine. Patients with a primary myopathy may display increased sensitivity to non-depolarising muscle relaxants. The use of drugs with acetylcholine-like actions (succinylcholine, reversal agents) should be avoided due to the danger of triggering muscle spasms in patients with myotonic disease and the risk of rhabdomyolysis in patients with dystrophic muscle disease. Irrespective of the type of muscle disease present, titration of the dose of muscle relaxant should always be done using a nerve stimulator.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia↗
PubMed1994

Prevalence and pattern of symptoms in patients with cancer pain: a prospective evaluation of 1635 cancer patients referred to a pain clinic.

In a prospective study, the prevalence of 15 physical symptoms and symptom groups was evaluated in 1635 cancer patients referred to a pain clinic. In addition to pain, patients suffered an average of 3.3 symptoms: insomnia (59%), anorexia (48%), constipation (33%), sweating (28%), nausea (27%), dyspnea (24%), dysphagia (20%), neuropsychiatric symptoms (20%), vomiting (20%), urinary symptoms (14%), dyspepsia (11%), paresis (10%), diarrhea (6%), pruritus (6%), and dermatological symptoms (3%). While symptom prevalence was influenced by tumor site, pain intensity, and opioid treatment, only a minor relationship was seen between symptoms and gender, age, or tumor stage. The data emphasize that it is not sufficient to simply address pain during the treatment of patients with cancer pain; a more global approach to symptom management is necessary.

Adolescent↗
PubMed1994

[Incidence of myocardial bridges after adrenergic stimulation and decreasing afterload in patients with angina pectoris, but normal coronary arteries].

The prevalence of myocardial bridging in patients with angina pectoris but normal coronary arteries was evaluated in 1780 patients who consecutively underwent coronary angiography. 62 patients (3.5%) were free of coronary atherosclerosis or other organic heart disease. In four of these patients systolic narrowing of the LAD was present. The other 58 patients received 0.2 mg nitroglycerin (NTG) intracoronarily and 30 micrograms/ml orciprenalin (ORC) intravenously up to a heart rate of 130/min. Repeated angiography revealed systolic compression of the LAD due to myocardial bridging (MB) in 40% (25 of 62). The length of MB raised from 1.4 +/- 0.9 cm to 2.1 +/- 1.1 cm (p < 0.001) after NTG and to 2.8 +/- 1.1 cm (p < 0.001) after ORC. Coronary luminal stenosis increased from 48 +/- 29% to 67 +/- 25% after NTG (p < 0.001) and to 83 +/- 18% (p < 0.001) after ORC. The prevalence of myocardial bridging in 40% of patients with stress-induced angina pectoris but normal coronary arteries is high. Nearly always coronary compression by myocardial bridging is only evident after adrenergic stimulation or after afterload reduction. Therefore, NTG and ORC are useful drugs to facilitate diagnosis of myocardial bridging by increasing coronary compression.

Adult↗
PubMed1994

Dose-response relationship of rocuronium bromide during intravenous anaesthesia.

The dose-response relationship and time course of neuromuscular block following bolus injections of rocuronium was determined in four groups of nine patients each under nitrous oxide-narcotic anaesthesia. Each patient received a total of 800 micrograms kg-1 rocuronium in two divided doses, i.e. 120 and 680, 200 and 600, 250 and 550, or 300 and 500 micrograms kg-1. The respective second dose was injected when, following the first dose, the evoked twitch tension had recovered to 95% of its control value. The mean ED50 and ED95 values, calculated from the first doses, were 103 and 271 micrograms kg-1, respectively. The DUR25 ranged between 11 +/- 4 (200 micrograms kg-1) to 14 +/- 3 min (300 micrograms kg-1) following the first and from 30 +/- 6 (500 micrograms kg-1) to 43 +/- 11 min (680 micrograms kg-1) following the second doses. The recovery index following the second doses varied between 14 +/- 5 (500 micrograms kg-1) and 24 +/- 20 min (600 micrograms kg-1), more than twice as long as following the first doses. We conclude that rocuronium is a muscle relaxant of low potency with an intermediate duration of action.

Adult↗
PubMed1993

Variability of pipecuronium neuromuscular blockade.

The dose-response relationship and the variability of the time variables in pipercuronium neuromuscular blockade were studied in 29 patients (ASA physical status 3) during halothane anaesthesia. The ED95 (twitch tension) was determined in 9 patients using the cumulative dose response technique. Another 20 patients received the resulting ED95 as a single bolus. The mean ED95 was 35 micrograms.kg-1 (95% confidence interval: 29-41 micrograms.kg-1). Following bolus injection of 1.ED95, an 80-100% twitch depression was achieved within 4.6 +/- 1.3 min (mean +/- s.d.). The duration from end of injection of pipecuronium to 25% twitch recovery, the time from 25% to 75% twitch recovery, and the time from 25% twitch recovery to the train-of-four ratio (TOF) returning to 0.7 was 35 +/- 14, 37 +/- 26, and 63 +/- 27 min, respectively. The time from end of injection to TOF = 0.7 varied within a 2-h range (54-160 min). Thus, the time variables in pipecuronium neuromuscular blockade were as poorly predictable as those reported in the literature on pancuronium, alcuronium and doxacurium.

Adult↗
PubMed1993

Validation of World Health Organization guidelines for pain relief in head and neck cancer. A prospective study.

In a prospective study of 167 patients with head and neck cancer, we assessed the causes and mechanisms of pain, as well as the efficacy and side effects of analgesic treatment, along World Health Organization (WHO) guidelines. The majority of patients had pain caused by cancer (83%) and/or treatment (28%), 4% had pain due to debility, and 7% had pain unrelated to cancer. Palliative antineoplastic treatment was performed in 32% of patients. Systemic analgesics were administered on 97% of a total of 8,106 treatment days, and coanalgesics or adjuvant drugs on 100%. The treatment proved to be very successful, as severe pain was experienced only during 5% of the observation period. In the absence of serious side effects, the most frequent symptoms observed were insomnia, dysphagia, anorexia, constipation, and nausea. The use of analgesic and adjuvant drugs along WHO guidelines to treat pain in head and neck cancer is highly effective and relatively safe.

Adolescent↗
PubMed1992

[Long-term follow-up of thrombolytic treatment of acute infarct in combination with acute and elective revascularization].

From March 1983 to June 1986 in 206 patients with acute transmural myocardial infarction, combined intravenous and intracoronary therapy with streptokinase was initiated. After intravenous thrombolysis and randomization in two groups we performed a coronary angiography with selective intracoronary lysis. Infarct related vessels still occluded after intracoronary streptokinase application were opened mechanically in group I. In group II we performed additionally a percutaneous transluminal coronary angioplasty (PTCA) after mechanical recanalisation (occluded vessels) or after thrombolysis (open vessels). In 85 of 87 cases in group II, PTCA could be performed in the acute phase. Elective PTCA was performed in 22 patients of group I (21%) and in nine patients of group II (9%). Up to five years after myocardial infarction, coronary artery bypass grafting (CABG) was necessary in 22 patients (21%) of group I and in 23 patients (22%) of group II. Within four weeks after infarction CABG was performed in 32% and 17% of group I and II respectively. The six-year survival rate was 78% in group I and 82% in group II. Taken all patients together, the six-year survival rate was significantly higher (p = 0.002) for those with early reperfusion (less than or equal to 3.5 h). The survival rates of CABG-patients, PTCA-patients and patients without reperfusion were 91%, 74% and 65% respectively. Streptokinase thrombolysis results, combined with acute or elective PTCA and/or coronary bypass surgery, in a high six-year survival rate after acute transmural myocardial infarction. This rate is about 20% higher than ten years ago.

Angioplasty, Balloon, Coronary↗
PubMed1992

[Curare and its successors. A 50-year's evolution].

The introduction of curare into clinical anaesthesia by Griffith and Johnson in 1942 contributed to the termination of the era where anaesthesia was a reversible intoxication rather than the result of controlled drug action. Curare allowed general anaesthesia to be reduced to a lighter level, thereby conferring a significant safety factor to the patient. Both the shortage in supply of crude curare and its variable composition led the search for synthetic curare analogues conferring well defined pharmacodynamic and pharmacokinetic properties. Based on the chemical structure of tubocurarine which has been known since 1935 the efforts concentrated on bisquaternary ammonium compounds. Gallamine was the only synthetic curare analogue to contain three quaternary ammonium groups. This drug had significant undesired vagolytic effects. In 1951 succinylbischoline appeared to be the ideal muscle relaxant, particularly with respect to its fast onset and short duration of action. The disadvantages of its depolarising mechanism of action which were appreciated during the years to follow prevented the concept of depolarising neuromuscular blockade to be pursued further. With other muscle relaxants, including curare itself, histamine release, vagal blockade and ganglionic blockade were undesired effects to be eliminated in future compounds. Improved understanding of structure-activity relationships turned out to be an indispensable tool for future research. This in turn required more elaborate methods in chemical analysis, in electrophysiology of the motor endplate, and in ultrastructural research. As a result, alcuronium and pancuronium became available in the late sixties and early seventies. Both muscle relaxants had a non-depolarising mechanism of action with reduced side effects relative to curare. From now on better techniques for pharmacodynamic and pharmacokinetic research became available resulting in research activity with particular emphasis in this field. Researchers became aware that new muscle relaxants should be designed for larger volumes of distribution and more rapid biodegradation than those currently available. Concurrently, anaesthesia techniques had changed in a way to use intubation and mechanical ventilation as a routine procedure. The risk of intraoperative hypoventilation and hypoxemia was eliminated, yet, due to the lack of adequate monitoring techniques the slow recovery from curare, alcuronium or pancuronium neuromuscular blockade was hardly appreciated.(ABSTRACT TRUNCATED AT 400 WORDS)

Anesthesiology↗
PubMed1992

Mivacurium: dose-response relationship and administration by repeated injection or infusion.

The dose-response relationship and neuromuscular blockade after infusion or repeated injection of mivacurium were studied in 65 patients in nitrous oxide-narcotic anesthesia. The ED95 (twitch tension) was determined in 45 patients by intravenous injection of a single bolus of 30, 39, 47, 54, or 60 micrograms/kg (9 patients per dose). Another 20 patients received an initial bolus of 2 x ED95 followed either by an infusion started at 5% twitch recovery (i.e., 95% depression) and adjusted to sustain 95% twitch depression (n = 10) or by repeated injection of 0.6 x ED95 whenever twitch tension had recovered to 25% of control (n = 10). Five patients in each of these two groups received 7 micrograms/kg of neostigmine at 25% twitch recovery, and the others recovered twitch tension spontaneously. The mean ED95 was 73 micrograms/kg. A 2 x ED95 bolus was followed by complete twitch depression within 2.2 +/- 0.7 min. The mean infusion rate resulted in 6 +/- 2 micrograms.kg-1.min-1. The ensuing recovery index was 6 +/- 3 min. A 6 +/- 2 min recovery index was found after up to 10 repeat injections given every 9 +/- 3 min. There was no significant effect of neostigmine in both groups. In conclusion, the recovery indices after the infusion or repeat injection of near-equal doses of mivacurium were identical.

Adolescent↗