Biomedical subjects

J Boldt

Publications and source records attributed to J Boldt.

At least 307 records · Page 17Linked to original sources

PubMed1987

Low-dose fentanyl analgesia modified by calcium channel blockers in cardiac surgery.

The hypothesis that calcium channel blockers can potentiate and prolong the anti-nociceptive effects of opioids was tested. Forty-five men scheduled for aorto-coronary bypass operation received fentanyl according to their individual demands (haemodynamics, clinical parameters). The patients were allocated at random into three groups receiving either nimodipine 1.0 microgram kg-1 min-1 (Group 1, n = 15), nifedipine 0.70 microgram kg-1 min-1 (Group 2, n = 15), or no calcium channel blocker (Group 3, n = 15). Cerebral activity was monitored using a computerized spectral analysing system before and during the operation. The total amount of fentanyl required was significantly lower in the nimodipine group than the control group (-71%, P less than 0.001), whereas the nifedipine group did not differ from the control group. Quality of intra-operative anaesthesia was comparable in the three groups with respect to clinical observations (amnesia, sweat, tears, pupils), and the post-operative course was similar in all patients as well. Cerebral activity during the nimodipine-supplemented opioid anaesthesia was higher in the faster frequency bands (13-30 Hz). Power level in the beta range was most pronounced in Group 1, whereas power in the alpha range was similar in the calcium channel-blocker groups. The major conclusion was that nimodipine but not nifedipine administration can reduce fentanyl requirements during surgical procedures without influencing the quality of anaesthesia.

Analgesia↗

PubMed1987

[Haemoseparation in heart surgery].

The Haemonetics Cell-Saver, a device developed for the recovery of autologous blood, was evaluated at our department, the major areas of concern being: quantity of blood salvaged, reduction in blood bank usage and possible monetary saving. In addition, various coagulation analyses were performed at frequent intervals. This study consisted of 292 patients undergoing cardiac surgery, who were randomly divided into two groups: 148 patients (group I) receiving autotransfusion (immediate centrifugation of oxygenator content after termination of cardiopulmonary bypass) were compared to 144 patients without autologous transfusion (group II). In the group of autotransfused patients, a mean of 2.27 units of bank blood were used throughout their entire hospital stay, as compared to 6.12 units of homologous blood in the other group (II) without autotransfusion. There were no significant differences between the two groups in respect of laboratory parameters and clinical course during the perioperative period. The data presented indicate a significant reduction in bank blood usage, thus protecting the patients from various hazards accompanying homologous blood transfusion (hepatitis, AIDS). Since the cost of Haemonetics software is recovered by 1.25 units of bank blood, a cost reduction of about US $135.-was achieved.

Blood Coagulation Tests↗

PubMed1987

[Nitrous oxide: modification of the hemodynamics in patients with coronary heart disease].

The haemodynamic effects of 70%, 50% and 30% N2O--compared to 100% O2--were studied in 20 patients undergoing coronary artery bypass grafting. The measurements-performed after an equilibration phase of 10 minutes--were made preoperatively but after induction of anaesthesia with 0.3 mg/kg bw etomidate, 0.01 mg/kg bw fentanyl and 0.1 mg/kg bw pancuronium bromide. In relation to N2O concentrations, mean arterial pressure (-4.8%), total systemic resistance (-7.9%) and stroke volume index (-6.4%) decreased moderately, whereas the cardiac index remained unchanged and the heart rate increased (+9.7). Total pulmonary vascular resistance was always within the physiological range, as were the triple index and the rate pressure product. In patients with coronary heart disease cardiovascular functions are compromised in close relation to the degree of the underlying disease. In accordance with other investigators, nitrous oxide should not be used in patients with impaired left ventricular function because of the possibility of deterioration of myocardial function. In such cases, amnesia should be achieved by means of other agents.

Anesthesia↗

PubMed1987

[Modified substitution of intracellular cations].

In order to ascertain the effect of modified supplementation of electrolytes and trace metals on intracellular uptake, 75 patients undergoing mitral valve replacement were randomly divided into three groups: group A (n = 25) received potassium and sodium chloride while group B (n = 25) was treated with potassium aspartate; in group C (n = 25), a balanced solution of electrolytes and trace metals (Inzolen) with aspartate as the anion was given. The treatment in the three groups was administered on the basis of frequently measured plasma levels of potassium and sodium. Anesthesia was similar in all patients; cardiac arrest was performed by crossclamping of the aorta using "Bretschneider's cardioplegia" for sodium withdrawal. After removal of the mitral valve, a sample of papillary muscle was obtained and analyzed by atomic absorption for its content of sodium, potassium, magnesium, zinc, and copper (Na, K, Mg, Zn, Cu). Sodium levels in papillary tissue were below the normal range in all groups and without differences depending upon the kind of treatment. Potassium levels in group A, however, (KCl) were markedly below those in groups B and C (aspartates). A similar effect could be observed with respect to tissue levels of Mg, Zn, and Cu. Supplementation of trace metals (group C) had no additional effect on tissue concentrations: there were no significant differences between group B (K aspartate) and group C (K-, Mg-, Zn-, Cu-, Na aspartate). Our results stress the importance of effective treatment of electrolyte and trace metal deficiencies. The present data suggest that the utilization of intracellular cations can particularly be improved by using solutions with aspartate as the anion.

Adult↗

PubMed1986

The influence of extracorporeal circulation on extravascular lung water in coronary surgery patients.

The influence of extracorporeal circulation (ECC) on extravascular lung water (EVLW) was investigated in a total of 45 consenting patients undergoing coronary artery bypass surgery. The patients were subdivided into 3 groups according to positive fluid balance during ECC: 1. less than 500 ml; 2. 500 to 1500 ml; 3. 1500 to 3000 ml. Lung water measurement was performed intraoperatively using the thermal green-dye double indicator dilution technique, with indocyanine green and a microprocessed lung water computer, before and after ECC. In the group with high positive fluid balance during ECC (group 3) EVLW - increase was more pronounced (5.18 ml/kg----8.18 ml/kg) than in the groups with lower positive fluid input (group 1: 5.35 ml/kg----5.68 ml/kg, group 2: 5.56 ml/kg----6.70 ml/kg). Extravascular lung water increase was accompanied by a deterioration of pulmonary gas exchange demonstrated by the greatest decrease of paO2 in group 3 (490 mmHg----243 mmHg). No significant relationship of lung water changes to various hemodynamic parameters was observed in this study.

Body Water↗

PubMed1986

[Volume replacement with a new hydroxyethyl starch preparation (3 percent HES 200/0.5) in heart surgery].

In a randomized study including 55 patients undergoing elective aorto-coronary bypass surgery efficacy of a low concentrated hydroxyethylstarch (3% HES 200/0.5) was tested after extracorporeal circulation (ECC). All patients received 1,000 ml autologous washed erythrocytes (cell saver) and 400 ml fresh frozen plasma (FFP). Thereafter patients were randomized into 4 groups. Hemodynamic parameters, laboratory parameters as well as extravascular lung water (EVLW - double indicator dilution technique) were measured before ECC as well as before and after infusion therapy. With regard to hemodynamic efficiency and the change in laboratory data no relevant differences between group I, II and III could be seen. EVLW-measurement demonstrated the lowest increase in lung water after infusion of HES; simultaneously pulmonary gas exchange was less compromised in comparison to the other infusion groups. 3% HES 200/0.5 solution can be considered as an effective volume substitute with short intravascular retention time, which seems to be of advantage in patients coming off extracorporeal circulation.

Blood Volume↗

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

[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

[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

[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↗

PubMed1985

[Effect of an introductory dose of etomidate, methohexital and midazolam on adrenal cortex function before and after ACTH-stimulation].

The adrenocortical function after induction of anaesthesia using either etomidate, methohexital or midazolam was examined in 30 patients undergoing open heart surgery (ACVB). Midazolam and methohexital did not suppress the typical stress response assessed from the magnitude of the ACTH, cortisol and aldosterone levels. The ACTH-test was also normal. In contrast, induction of anaesthesia using etomidate led to a progressive fall in cortisol and aldosterone accompanied by an increase in ACTH. The ACTH-test resulted in only a minor increase in adrenocortical hormones. Thus an induction dose of etomidate, in contrast to methohexital and midazolam, markedly alters the normal function of the adrenal cortex. This side-effect of etomidate lasts for at least 4 hours but is no longer detectable after 24 hours.

Adrenal Cortex↗

PubMed1985

Influence of nimodipine on cardiovascular parameters during coronary surgery.

A total of 78 patients about to undergo open-heart surgery (ACVB) were given nimodipine, a new calcium antagonist, in different doses (0.5 or 1.0 microgram/kg body weight min or 0.03/0.06 mg/kg h) before and during extracorporeal circulation. During infusion (10 to 40 min), the hemodynamic parameters were recorded, including intrapulmonary pressures, the cardiac output and the left ventricular contractility parameters LVP and dp/dtmax. The administration of nimodipine resulted in a dose-dependent reduction of the pulmonary and peripheral vascular resistance with a subsequent decrease of the mean arterial pressure or perfusion pressure (during extracorporeal circulation). The left ventricular pressure (LVP) was reduced, whereas sometimes the cardiac output increased considerably. The contractility (dp/dtmax) was not impaired even by the high nimodipine dose. The heart rate, too, remained unaffected. The nimodipine dose of 0.5 microgram/kg min used in neurosurgery for therapy did not cause any clinically relevant decrease in blood pressure; at higher doses (greater than or equal to 1.0 microgram/kg min) an excessive fall of the diastolic pressure must be avoided in patients with severe (coronary) sclerosis, because a reduced perfusion of poorly vascularized myocardial regions can occur despite improved global perfusion.

Blood Pressure↗

PubMed1985

The detection of penicillin-resistant pneumococci. The compliance of hospital laboratories with recommended methods.

Isolations of pneumococci with diminished susceptibility to penicillin have been reported with increasing frequency in recent years. The first reported isolations of such organisms in Tennessee occurred in December 1982, and prompted a survey of acute-care hospitals to determine the methods being used to test pneumococcal isolates for penicillin susceptibility. All 77 acute-care hospitals in Tennessee with 100 or more beds were surveyed. Eighteen (23%) did not test the penicillin susceptibility of any pneumococcal isolates obtained from blood or cerebrospinal fluid. Thirty-eight hospitals (49%) tested some or all such isolates, but did not perform the tests in accord with established standards; 21 (27%) properly tested all such isolates. There was no correlation between the proper testing of pneumococcal isolates for penicillin susceptibility and the mode of governance, numbers of beds, or medical school affiliations of the respondent hospitals. It is recommended that appropriate pneumococcal isolates be tested for penicillin susceptibility. Such testing is most reliably performed by the disk diffusion method, using a 1-microgram oxacillin disk.

Adult↗

PubMed1985

Acrosomal status evaluation in human ejaculated sperm with monoclonal antibodies.

An important question in mammalian gamete physiology concerns how capacitation and the occurrence of acrosome reactions in motile sperm relate to fertility. Evaluation of these relationships has been restricted by practical limitations because rapid, quantitative assays are unavailable. We have developed a rapid, reproducible assay for the evaluation of acrosomal status utilizing monoclonal antibodies specific to antigens localized in the acrosomal cap region of the sperm head. Mice were immunized with human ejaculated sperm preparations and the resultant hybridomas producing antisperm antibody were selected by solid-phase radioimmunoassay and indirect immunofluorescence (IIF). Two monoclonal antibodies (HS-19, HS-21) recognized target antigens restricted to the acrosomal cap by IIF, and 87 +/- 8.5% of the sperm in fresh ejaculates from 10 different sperm donors showed positive cap fluorescence with these reagents. Loss of HS-21 binding as measured by IIF was correlated with disappearance of the acrosomal cap as observed directly by transmission electron microscopy. Acrosomal disappearance, artificially induced in vitro using the calcium ionophore A23187, also resulted in a loss of HS-21 binding. The induction of acrosomal loss by ionophore was dependent upon extracellular calcium. The data presented suggest that specific monoclonal antibodies can be used for the rapid evaluation of acrosomal status in mammalian sperm.

Acrosome↗