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Biomedical subjects

J Radke

Publications and source records attributed to J Radke.

At least 73 records · Page 4Linked to original sources
PubMed1989

[A case of bronchospasm under isoflurane anesthesia].

Isoflurane is generally considered to have little effect on bronchomotor tone. The following case report shows that isoflurane anesthesia can be associated with severe bronchospasm. A 9-year-old girl (35 kg, 140 cm) with no history of asthma or drug sensitivity was scheduled for emergency appendectomy. Anesthesia was induced with fentanyl, methohexital, and vecuronium. Breath sounds were normal prior to induction and after endotracheal intubation. Isoflurane was added to the gas mixture 5 min after the last injection. Almost immediately after isoflurane was added the mean inspiratory pressure increased from 15 to ca. 35 cm H2O, expiration was prolonged, and wheezing was heard on auscultation. End-expiratory CO2 increased from 5.1% to more than 8% (pCO2 ca. 60 mmHg). Halothane was substituted for isoflurane and theophylline was injected, i.v. shortly after which the inspiratory pressure decreased, the wheezing improved, and the end-expiratory CO2 returned to normal. The remaining course and postoperative period were uneventful. Isoflurane is considered to be the causative agent in this case. Other possible mechanisms are discussed and pertinent literature is reviewed.

Anesthesia↗
PubMed1984

[Rewarming from moderate to deep hypothermia: plasma catecholamine content, metabolism and circulatory function. 2 case reports].

Two patients were rewarmed from hypothermia (esophageal temperature 27.2 degrees C, 27.5 degrees C respectively). The first case suffered from head-injury after alcohol ingestion and was deeply comatose. A metabolic or cardiovascular regulatory response to cold was not observed in this patient. The relationship between esophageal temperature and whole-body-oxygen consumption was quantified with a Q10 of 2.75 during rewarming (27.2-37.2 degrees C). His epinephrine levels were greatly elevated to 1,000 pg/ml whereas norepinephrine levels were only moderately increased to 250 pg/ml. Premature ventricular contractions (PVCs) during intubation or from the pulmonary artery catheter were not observed. The second patient was a 87 year old man with accidental hypothermia. He exhibited shivering at an esophageal temperature of 27.5 degrees C which indicated persistent thermoregulation. In contrast to the first case his norepinephrine levels were elevated to 1,500 pg/ml and his epinephrine levels only to 450 pg/ml. After onset of surface rewarming an additional increase in norepinephrine levels was observed and an increasing rate of PVC's (15/min) recorded, which ceased when temperature returned to normal. Our observations indicate that part of the cardiac complications during rewarming from deep hypothermia may result from thermoregulation and additional catecholamine liberation.

Adult↗
PubMed1981

[The effects of midazolam on the general circulation, cerebral blood-flow and cerebral oxygen consumption in man (author's transl)].

The effects of midazolam, 0.2 mg/kg b.w., on cerebral blood flow, cerebral oxygen consumption and brain metabolism were studied in 8 patients scheduled for intracranial aneurysm surgery. All patients were anesthetized with fentanyl and N2O; arterial pCO2 and pO2 were maintained within the normal range by controlled ventilation. Midazolam produced minimal effects on the general circulation. Cerebral blood-flow decreased about 11% while cerebral oxygen consumption essentially remained unchanged. Cerebral perfusion pressure slightly decreased due to a reduction in mean aortic pressure. In three patients with elevated intracranial pressure midazolam decreased intracranial pressure significantly while there was no change in the other patients. It is concluded that midazolam is of no harm in patients with intracranial aneurysms. Furthermore this rapidly acting drug in addition to other measures might be of some benefit in patients with elevated intracranial pressure when immediate reduction of cerebral blood volume is desired.

Adolescent↗
PubMed1980

Effects of the Myo-monitor on cardiac pacemakers.

Interference of Myo-monitor stimulus on normal function of cardiac pacemakers depends on the sensitivity of the pacemaker and the amplitude setting of the stimulator. Because of electrical isolation of the fixed-rate pacemaker, it is resistant to interference and is unaffected by the Myo-monitor.

Electric Stimulation↗
PubMed1980

[Haemodynamics, coronary blood flow and myocardial metabolism in man: effects of sufentanil and fentanyl (author's transl)].

The effects of sufentanil (0.7 microgram/kg) and fentanyl (7 microgram/kg) on general and coronary haemodynamics and myocardial metabolism were studied in 6 and 9 patients without cardiovascular disease. Both drugs produced a slight reduction in heart rate, cardiac index and mean aortic pressure, whilst peripheral vascular resistance remained unchanged. There was a decrease in dp/dtmax and a slight increase in LVEDP suggesting minimal depression of myocardial contractility. Myocardial blood flow and myocardial oxygen uptake slightly decreased due to reduction in pressure-, volume- and frequency-load and dp/dtmax. With both drugs arterial concentrations of glucose, lactate, pyruvate and free fatty acids and their myocardial uptake did not change significantly. Clinically equi-anaesthetic doses of sufentanil and fentanyl produced almost identical effects on general and coronary haemodynamics. With regard to the cardiovascular actions sufentanil offers no advantage over fentanyl.

Adult↗
PubMed1980

[Controlled ventilation in a patient with acute exacerbation of a chronic myeloic leucaemia. A case report (author's transl)].

High counts of myeloid cells lead to erroneous results of blood gas measurements due to high rate of metabolism. This in vitro metabolism simulates hypoxaemia in the common chemical analyses. Therefore problems in the correct interpretation of blood gas measurements during controlled ventilation may arise, demonstrated in our case report of a patient with chronic myeloid leucaemia in acute stage. Immediate blocking of blood oxydative phosphorylation in the sample withdrawn is necessary in order to determine actual values which are important for adequate artificial ventilation.

Adult↗
PubMed1980

[Synergistic or antagonistic interaction between dopamine and droperidol (DHB) on general hemodynamics and kidney function. An animal experiment study].

We investigated the renal effects of low and high concentrations of dopamine (4 and 10 microgram . kg-1 . min-1) in dog experiments. Dopamine increased renal blood flow, glomerular filtration rate, renal oxygen consumption and urinary excretion. These effects could not be antagonized by droperidol. In clinical doses both drugs rather act synergistically upon the cardiovascular system and renal function.

Animals↗
PubMed1980

[Intensive care of severe preeclampsia-eclampsia. A report on 22 cases (author's transl)].

22 patients with severe preeclampsia-eclampsia were treated in our Intensive Care Unit from 1972 to 1978. Control of convulsions was achieved by diazepam, diphenylhydantoin and phenobarbital. In 11 comatose patients brain monitoring was carried out by frequent neurological examination and use of computerized x-ray tomography; aspiration of gastric contents was prevented by nasotracheal intubation. Brain oedema therapy included controlled hyperventilation, steroids and mannitol (7 patients). 10 patients with respiratory failure (due to pulmonary oedema, "shock lung" or aspiration pneumonitis) were treated by mechanical ventilation. Diastolic blood pressure above 100 mm Hg was reduced by hydralazine. Diuresis was induced by normalization of hypovolaemia with albumin and plasma expanders. Six patients died (27%); main causes of death included intracerebral haemorrhage, brain oedema, heart failure, acute pulmonary thromboembolism and bleeding from DIC.

Acute Kidney Injury↗
PubMed1979

Myocardial metabolism and oxygenation in man awake and during halothane anesthesia.

Cardiac catheters were placed in seven healthy conscious patients so that aortic and left ventricular pressures (and the derivative), cardiac output (thermodilution) and myocardial blood flow (argon washin) could be measured. Blood was drawn for measurement of arterial blood-gas and arterial and coronary venous oxygen, glucose, lactate, pyruvate and fatty acid values. After induction of anesthesia by inhalation of halothane, the measurements were made during administration of low (0.70%) and high (1.54%) end-tidal halothane concentrations. Myocardial function decreased in a dose-related fashion without a change in heart rate. Myocardial blood flow and oxygen consumption were depressed in a similar manner. Myocardial oxygen extraction decreased and lactate did not change, suggesting that myocardial oxygenation was adequate. The heart rate-systolic blood pressure product correlated poorly with myocardial oxygen consumption. Systolic blood and the contractile performance index dP/dt/IP were better correlated with myocardial oxygen consumption, but the value of the coefficient was still low. Without significant changes in heart rate, systolic blood pressure is the best correlate of myocardial oxygen consumption in healthy man during the myocardial depression produced by halothane.

Adult↗
PubMed1979

[The effects of halothane-, nitroprusside- and trimethaphan-induced hypotension on cerebral blood flow and intracranial pressure (author's transl)].

Arterial hypotension to about 50 mm Hg mean pressure was induced in anaesthetized and artificially ventilated dogs by halothane, nitroprusside, and trimethaphan to study their effects on cerebral blood flow and intracranial pressure during hypotension. During nitroprusside induced hypotension there was a 32% increase in cerebral blood flow above control and a marked decrease in cerebral arteriovenous oxygen content difference indicating luxury perfusion of the brain. Cerebral blood flow remained high even 30 min after termination of hypotension. During halothane and trimethaphan hypotension cerebral blood flow remained unchanged. In all groups epidural pressure did not change substantially during hypotension but increased during recovery from nitroprusside hypotension by a maximum of 72% above control. It is concluded that during and after nitroprusside hypotension loss of cerebral autoregulation occurs which may result in a marked rise in intracranial pressure. Special vulnerability seems to exist shortly after termination of induced hypotension when arterial pressure begins to rise and brain perfusion follows a pressure-flow relationship.

Animals↗
PubMed1978

[Effects of isovolaemic haemodilution on pulmonary gas exchange and haemodynamics (author's transl)].

In experiments on 11 closed chest dogs the behaviour of pulmonary gas exchange and haemodynamics during isovolaemic haemodilution with 6% dextran was studied. The dogs were ventilated artificially (IPPB, PEEP = 0) with room air. After haemodilution a slight increase of arterial PO2 from 86 to 92 mm Hg was found. In another series of experiments an inspiratory O2-concentration of 25% was applied resulting in an increase of arterial PO2 from 106 to 113 mm Hg. In both series a decrease of alveolararterial PO2 gradients was observed. Effective pulmonary capillary blood flow varied in accordance with changes of cardiac output. Thus intrapulmonary shunt is supposed to have remained constant. The changes of pulmonary O2 diffusing capacity could be explained by the effect of haemodilution per se. At the end of the experiments ventilation was changed by adding a positive endexpiratory pressure of 8 cm H2O resulting in a decrease of arterial PO2 and a steep fall of cardiac output. In conclusion, isovolaemic haemodilution leads to only negligible variations of pulmonary gas exchange which should not be of any clinical importance.

Animals↗
PubMed1977

[A new volumetric infusion pump (author's transl)].

Our experience with a new volumetric infusion pump "Tekmar T 92" is reported. Over a period of months the reported advantages of the instrument were investigated on three separate units. Some few disadvantages for routine use were observed.

Air↗
PubMed1977

[Pulmonary gas exchange during isovolaemic haemodilution (author's transl)].

In experiments on 6 closed chest dogs the behaviour of pulmonary gas exchange during isovolaemic haemodilution with 6% dextran was studied. The dogs were ventilated artificially using an inspiratory gas mixture containing 25% O2. A slight increase of arterial Po2 values was found. This change was accompanied by a decrease in alveolar-arterial Po2 and Pco2 gradients. The size of effective pulmonary capillary blood flow varied in accordance with the size of cardiac output. The changes of pulmonary O2 diffusing capacity could be explained by the effect of haemodilution per se.

Animals↗
PubMed1975

[Comparison of tolerance to ischemia in human and animal myocardium during various forms of induced cardiac arrest (author's transl)].

In a total of 16 patients the tissue pH was determined on myocardium both during surgery and on isolated samples. Cardiac arrest was induced by hypothermal infusion cardioplegia and external cooling. In the isolated human myocardium section pH values were continuously determined at 15 degrees C. Parallel to these measurements samples were taken for electron microscopic examinations. In this way the pH limit under which the human myocardium cannot be revived could be visualized by additional morphologic examination. These results and those from the intrasurgical measurements with a fixed heart muscle surface probe were compared with each other and with results from animal experiments.

Adenosine Triphosphate↗
PubMed1975

[Anatomy of the lateral malleolar sulcus - a contribution to the causation of displacement of peroneal tendons (author's transl)].

On 100 specimens of the fibula repeatable parameters were developed so as to measure the bony bed of the peroneal tendons and to evaluate the results statistically. The specimens were investigated frontally and in profile. And the sulcus was measured with a special tool. By determining height, width and slope of the walls of the groove absolute values were found which permitted differentiation between the various types of salcus.

Ankle Injuries↗
PubMed1975

[Anatomy of the sulcus of the extensor carpi radialis tendon (author's transl)].

The anatomy of the sulcus of the extensor carpi radialis tendon was analyzed in order to establish the importance of anatomic variation of the bony bed for the development of habitual dislocation of the tendon. Length, width and slope of the lateral walls were measured. Additional morphologic description permitted to distinguish 4 different types of sulcus. The results mean that the anatomy of the sulcus has only an indirect connection with dislocation, via laxity of the retinacula.

Humans↗