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Biomedical subjects

R Ritz

Publications and source records attributed to R Ritz.

At least 91 records · Page 5Linked to original sources
PubMed1983

Alpha 2 adrenoceptor-mediated vasoconstriction of arteries.

We investigated the possibility that adrenoceptors of the alpha 2 subtype mediate vasoconstriction of arteries in response to administered catecholamines. Clonidine, which in vitro, stimulates alpha 2-adrenoceptors was infused into a brachial artery in 12 subjects (0.48 micrograms/min/100 ml tissue for 3 min). Afterward, prazosin was infused intraarterially in the first six subjects (0.5 micrograms/min/100 ml for 10 min) and in the remaining subjects, phentolamine was infused (0.12 micrograms/min/100 ml) for 10 min. Subsequently, the clonidine infusion was repeated. Clonidine decreased forearm blood flow from 3.5 +/- 0.52 to 1.8 +/- 0.32 in the first six subjects and from 4.2 +/- 0.84 to 2.7 +/- 0.61 ml/min/100 ml in the other subjects. Alpha 1-Adrenoceptor blockade by prazosin increased forearm blood flow by 122.7 +/- 33.8% and combined alpha 1 and alpha 2 blockade by phentolamine by 127.2 +/- 29.9%, indicating much the same degree of postjunctional alpha-adrenoceptor blockade. Alpha 2-Adrenoceptor-mediated vasoconstriction by clonidine was abolished after phentolamine (9.1 +/- 2.29 and 9 +/- 2.51 ml/min/100 ml) but was still present after prazosin (7.8 +/- 1.7 and 4.8 +/- 1.6 ml/min/100 ml). The results suggest that, apart from the classical alpha 1 adrenoceptor, there is a second type of adrenergic receptor on smooth muscle cells that can mediate vasoconstriction, resembling the alpha 2-adrenoceptor pharmacologically.

Adult↗
PubMed1982

Sequential treatment of arterial occlusions with porcine plasmin and low dose streptokinase.

Sequential treatment of arterial occlusions of the leg with porcine plasmin and low dose streptokinase results in a strong systemic proteolysis as already seen in deep leg vein thrombosis. In 31 of 45 patients the blood flow through major arterial segments could be restored. Thrombolytic success is possible within the first two treatment days but for the majority of the cases fibrinolytic therapy for 3-6 days is needed. On the average treatment was 1 day shorter than in DVT cases. No statistical relationship between local thrombolysis and systemic proteolysis was detected. The thrombolytic efficacy of this regimen compares favourably with earlier experience on fibrinolytic therapy in arterial occlusions.

Adult↗
PubMed1982

Sequential treatment of deep leg vein thrombosis with porcine plasmin and low dose streptokinase.

Sequential treatment of deep leg vein thrombosis with porcine plasmin and low dose streptokinase (10,000-20,000 U/h) produces strong systemic fibrinolysis as demonstrated by the sustained decrease of euglobulin lysis time, of thromboplastin time values in percent, fibrinogen and factor V levels. There is a statistically significant negative correlation between thrombolytic results and euglobulin lysis time. Treatment period below 3 days are unlikely to give satisfactory results. Occluded vein segments with an apparent median age of 4 days including thrombi older than 10 days (20% of cases) are cleared with an average chance of 50%. Complete dissolution of all thrombi proximal to the crural veins has been demonstrated in 47/114 = 41.2%, some thrombolytic effects in 31/114 = 27.2% and treatment failure in 36/114 = 31.6%. The data favour laboratory monitoring of thrombolytic therapy.

Adult↗
PubMed1982

Side effects of thrombolytic treatment with porcine plasmin and low dose streptokinase.

In the sequential thrombolytic therapy with porcine plasmin and low dose streptokinase side effects are mainly due to bleeding, intolerance reactions are less important. Treatment had to be prematurely stopped in 42 (37%) of 114 DVT cases because of severe bleeding and in 12 (10%) due to intolerance reactions. The corresponding figures for the 45 cases with arterial occlusions are 15 (33%) and 2 (4%) respectively. The intensity of systemic proteolysis as represented by the thromboplastin time is significantly correlated with haemorrhagic manifestations. Macrohematuria and bleeding from puncture sites are the most frequent haemorrhagic complications followed by spontaneous bleeding into skin and muscles. Non-fatal intracranial bleeding occurred in 1 DVT case (0.9%) and in 2 patients with arterial occlusions (4.4%). The benefit of this potent thrombolytic regimen would greatly improve if a strong reduction of premature treatment stop could be achieved.

Animals↗
PubMed1982

[Follow-up of intensive medical care patients].

Increasing limitations on personnel and material in intensive care render a reevaluation necessary. Follow-up of critically ill patients might be a useful contribution to this. In 330 patients the situation during intensive care and the subsequent stay on the ward, as well as physical and psychological status 3 years later, were analyzed. In 96% the acute event necessitating intensive care corresponded to a preexisting chronic illness. Although the mean stay of 3,6 days in ICU was relatively short, total time of hospitalization exceeded that of patients who did not undergo intensive care. Three quarters of the 330 patients survived ICU and two thirds the subsequent hospitalisation. Half of the patients were still alive three years later, most under medical supervision for the same illness. 89 Patients could be followed up after three years; 84% were physically independent and 53% were at work, but 20% of these had had to change jobs. The later outcome in patients ventilated during intensive care was inferior in all respects. Comparing the quality of life to 1977, 33% of the patients described their physical capacity and 14% their mental activity as reduced. One third of the patients had specific memories of the stay on the ICU, such as pain, fear of being alone, of the illness or of the technical environment. In conclusion, three years after intensive care half of the patients had survived and in most of the cases a qualitatively satisfactory life style was possible.

Adolescent↗
PubMed1982

[Continuous computer-assisted monitoring].

Optimal monitoring of vital parameters in critically ill patients should be performed continuously with non-invasive and automatic methods including trend presentation of the data. Continuous measurements are now in frequent use in intensive care units, and non-invasive techniques are being increasingly explored. Besides automatic registration, computerization of monitoring allows trend presentation of the measured values and thereby improves diagnostic and therapeutic procedures. The characteristic peculiarities of a computer, i.e. acquisition, computing and presentation of the data, as well as storage capacity, enable simultaneous monitoring of several complex parameters, as is demonstrated by arrhythmia monitoring systems already in routine use. Optimal patient surveillance is described in three practical examples of computer application.

Arrhythmias, Cardiac↗
PubMed1982

[Slower lidocaine elimination and dose adjustment in patients with heart failure].

In 21 patients with acute coronary artery disease the influence of cardiac failure on the elimination of lidocaine (L) was evaluated by repeated serum level measurements during and after a therapeutic L-infusion. Lidocaine clearance (Cl) was less than 8 ml/min/kg in 9 of 13 cases with congestive heart failure (CHF), while in 7 out of 8 patients without CHF Cl-values were 8-12 ml/min/kg. Due to wide interindividual variability in the CHF group, however, mean values were not significantly different: 7.3 +/- 2.9 vs. 9.52 +/- 1.54 ml/min/kg (p greater than 0.05). In 3 patients receiving a simultaneous nitroglycerine infusion Cl was greater than 10 ml/min/kg despite clinical signs of CHF. The t 1/2 of L was significantly prolonged in patients with CHF: 4.29 +/- 2.14 vs. 2.43 +/- 0.58 h (p less than 0.05). It was not possible to determine individual L-dose requirements by bedside clinical examination alone. Serum level monitoring is therefore recommended in order to optimize L-therapy in patients with life-threatening arrhythmias, severe congestive heart failure and hypotension.

Arrhythmias, Cardiac↗
PubMed1982

Plasma adrenaline and noradrenaline in patients with acute myocardial infarction. Relationship to ventricular arrhythmias of varying severity.

Plasma adrenaline (A) and noradrenaline concentrations (NA) were determined in 41 patients admitted to the coronary care unit (CCU). Eleven with suspected acute myocardial infarction (AMI), subsequently excluded as a diagnosis, had significantly elevated A and NA compared with 20 normal resting subjects. Patients with proven infarcts but no ventricular fibrillation had even higher levels of A and NA. Nine patients with ventricular fibrillation as a complication of AMI showed the highest plasma catecholamine values on admission. Patients with AMI and congestive heart failure exhibited substantially increased A, while NA was only slightly elevated compared with that of AMI patients without congestive heart failure. High plasma catecholamines and the relationship between adrenaline and the severity of ventricular arrhythmias suggest that the sympathetic nervous system plays an important role in sustaining a vicious circle of increased myocardial damage and increased irritability during the acute phase of AMI.

Adult↗
PubMed1981

[Quality control of computer-assisted arrhythmia monitoring].

In the management of coronary care patients, continuous ECG analysis is best performed by a computerized monitoring system. For more than 2 years all the patients in this CCU have been monitored by the 78220 Hewlett-Packard arrhythmia monitoring system. As a quality control of the system the data of 15,068 alarm situations in 300 patients were first analyzed: the specificity of the system varied from 3% to 83% according to type and severity of arrhythmias. To evaluate the sensitivity of the system the amount of VES registered by Holter monitoring was then compared with the analysis by computerized monitoring during the same period of time: in a total of over 10,000 VES in 14 patients the sensitivity was 90%. Although the personnel of a CCU still have to deal with a large number of false positive alarms, a computerized arrhythmia monitoring system offers a higher degree of security for the patient than conventional monitoring.

Arrhythmias, Cardiac↗
PubMed1980

[Accuracy of clinical findings in patients with disturbed myocardial function in acute myocardial infarction].

The relationship between clinical findings and invasively measured hemodynamic data was investigated in a prospective trial of 70 patients with acute myocardial infarction. In 26 out of 27 consecutive patients without clinical signs of disturbed myocardial function, normal hemodynamic values were also found invasively. In 43 patients, depressed myocardial function was diagnosed on the basis of the clinical findings. These findings were verified in 38 patients (88%) by means of cardiac catheterization; 5 patients (12%) had normal hemodynamic values. In 26 patients with clinical signs of congestive heart failure, an attempt was made to identify non-invasively those with a low output (cardiac index less than 2/min/m2). Only 3 of the 6 patients with a low output could be identified by clinical examination alone. In one patient a low output was clinically diagnosed despite normal cardiac function measured invasively. In 16 patients, 48 subsequent clinical examinations were performed during treatment of congestive heart failure to identify either persistent elevated left ventricular filling pressure or low output; 15 (31%) were found to be incorrect when compared with the cardiac catheterization data. Patients with acute myocardial infarction and normal ventricular function can be identified with high accuracy by means of clinical examination alone. The clinical diagnosis of congestive heart failure was incorrect in 12% of the patients. A low output state in acute myocardial infarction is often overlooked in clinical examination alone. Of the clinical examinations on patients during therapy, 30% were incorrect. Invasive hemodynamic monitoring in acute myocardial infarction therefore appears to be unnecessary in patients with normal clinical findings, but in those with clinically diagnosed congestive heart failure it is mandatory for precise indication and evaluation of therapy.

Cardiac Catheterization↗
PubMed1980

[Methods of circulatory monitoring in intensive care units].

In a critically ill patient referred to an intensive care unit, clinical evaluation remains the first method in the assessment of cardio-circulatory status. In more complex cases direct measurement of standard hemodynamics must be performed at the bedside, for instance by the use of a Swan-Ganz thermodilution catheter. As alternatives to hemodynamic parameters, non-invasive techniques for the evaluation of left ventricular function such as echocardiography, radionuclide angiography, measurement of systolic time intervals and electrical impedance are presented. Their indications and limitations in comparison with hemodynamics are discussed.

Angiography↗
PubMed1979

[Hemodynamic consequences of the furosemide treatment of cardiac insufficiency in recent myocardial infarct].

Furosemide was administered intravenously to 11 patients with cardiac failure after acute myocardial infarction. After an initial loading dose furosemide was given four-hourly if the pulmonary capillary wedge pressure (PCW) was not normalized, i.e. less than or equal to 15 mm Hg. The comparison of the hemodynamic results with the results of a previous study with nitrates was as follows: like the nitrates furosemide lowered the PCW early, i.e. within 15 minutes from 22 +/- 3 to 18 +/- 5 mm Hg, but the therapeutic objective (PCW less than or equal to 15 mm Hg) was reached later than with nitrates. During the 24-hour observation period PCW and total peripheral resistance decreased steadily. The decrease of cardiac index to critical low values in some patients after a mean of 7.5 hours of therapy, and of the mean arterial pressure from 100 +/- 13 to 91 +/- 14 mm Hg, may limit the use of furosemide alone in these patients. During nitrate therapy PCW started to rise again after 12 hours in some patients, necessitating higher doses of nitrates with a corresponding decrease of diuresis. A combination of both forms of therapy may be of value and needs further investigation.

Aged↗