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Biomedical subjects

J Boldt

Publications and source records attributed to J Boldt.

At least 253 records · Page 14Linked to original sources
PubMed1990

Acute plasmapheresis during cardiac surgery: volume replacement by crystalloids versus colloids.

Acute plasmapheresis (APP) is an additional tool for blood conservation during cardiac surgery. In a randomized study of 60 aortocoronary bypass patients undergoing APP, the influence of replacement of the withdrawn autologous plasma (10 mL/kg) by either colloids (low molecular weight hydroxyethyl starch solution [6% HES 200/0.5]) or crystalloids (Ringer's solution) was investigated. APP was performed by means of a centrifugation technique producing platelet-poor plasma. During and after cardiopulmonary bypass (CPB), either a cell saver (CS) or a hemofiltration (HF) device was also used for blood concentration. Almost three times as much crystalloid as HES solution was necessary for replacement of autologous plasma. Fluid balance during CPB was significantly more positive in the crystalloid patients, particularly when a CS was used. Blood loss was highest in the crystalloid patients in whom a CS was used in addition to APP, and these were the only patients who needed packed red cells. The platelet count, AT-III and fibrinogen plasma concentrations, colloid osmotic pressure, albumin, and total protein were significantly less compromised in the patients with colloid volume replacement. These parameters were closest to control values in patients receiving colloid replacement and HF. It is concluded that colloid is preferred for replacement of autologous plasma withdrawn by APP, and HF is superior to the CS when the combined technique for blood conservation is used.

Coronary Artery Bypass↗
PubMed1990

Lung management during cardiopulmonary bypass: influence on extravascular lung water.

Progressive respiratory insufficiency secondary to cardiopulmonary bypass (CPB) is still a hazard after cardiac surgery. Pathophysiologically, impaired capillary endothelial integrity seems to be the fundamental lesion, followed by increased interstitial fluid accumulation. The reasons for this pulmonary damage are controversial; however, management of the nonperfused lungs during CPB has been widely neglected and may be partly responsible. In this study, 90 patients undergoing coronary artery bypass grafting were randomly divided into six groups (15 patients each) with different management of the lungs during CPB: group 1, lungs collapsed (0/0); group 2, static inflation with +5 cm H2O and F1O2 1.0 (+5/1.0); group 3, static inflation with +5 cm H2O and F1O2 0.21 (+5/0.21); group 4, static inflation with +15 cm H2O and F1O2 1.0 (+15/1.0); group 5, static inflation with +15 cm H2O and F1O2 0.21 (+15/0.21); and group 6, controlled mechanical ventilation as before start of CPB (positive end-expiratory pressure [PEEP] +5 cm H2O; F1O2 1.0) (ventilation). In addition to hemodynamic monitoring, extravascular lung water (EVLW) was measured by means of a double-indicator dilution technique with heat and indocyanine green. Measurements were performed after induction of anesthesia, before onset of CPB, and immediately after weaning from bypass, as well as 60 minutes and 5 hours after termination of CPB. Pulmonary gas exchange (PaO2) and intrapulmonary shunting (Qs/Qt) were also measured. Starting from comparable, normal baseline values, EVLW was increased in all groups after weaning from CPB, with the most pronounced increase in group 4 (maximum, +35%) and group 5 (+40%).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1990

Effects of nitrous oxide on endocrine stress response and haemodynamic parameters during coronary artery surgery.

To compare simultaneously the influence of nitrous oxide on haemodynamic parameters and on surgical stress response, 20 patients scheduled for coronary artery bypass graft were investigated during standardized modified neurolept anaesthesia. Before onset of cardiopulmonary bypass, one group received nitrous oxide and oxygen (2:1), whereas in the other group air with oxygen (F10(2) 0.33) was used. Increases in adrenaline, noradrenaline, ADH, and cortisol were slightly less and mean arterial pressure and cardiac output reached markedly lower levels in the nitrous oxide group. When nitrous oxide is not acceptable for a cardiac surgery patient during modified neurolept anaesthesia due to haemodynamic side effects enhancing intravenous application of anaesthetics to compensate the analgetic properties of the substance should be considered.

Adrenocorticotropic Hormone↗
PubMed1990

Haemodynamic effects of the phosphodiesterase inhibitor enoximone in comparison with dobutamine in esmolol-treated cardiac surgery patients.

In a randomized study, the haemodynamic effects of the new phosphodiesterase-III-inhibitor, enoximone, were compared with dobutamine in acutely beta-adrenoceptor blocked patients. Twenty patients scheduled for aorto-coronary bypass grafting suffering from tachycardia (heart rate (HR) greater than 100 beat min-1) were treated by infusion of esmolol, an ultra-short acting, selective beta 1-blocker. Twenty minutes after the start of esmolol, either enoximone 0.5 mg kg-1 as a bolus (n = 10) or dobutamine 5 micrograms kg-1 min-1 was administered. Haemodynamic effects were monitored for 40 min, including measurement of left ventricular haemodynamics. Esmolol reduced HR (-27%) and dP/dtmax (-38%) significantly in both groups. Cardiac index (CI) was decreased also. Enoximone increased Cl (+35%) and dP/dtmax (+39%) significantly, while no change in dobutamine-treated patients was observed. Systemic vascular resistance increased only in the dobutamine group (+44%).

Adrenergic beta-Antagonists↗
PubMed1990

Preoperative plasmapheresis in patients undergoing cardiac surgery procedures.

Donor plasmapheresis that is carried out weeks before the operation has proven to be of benefit in elective orthopedic patients with regard to reducing homologous blood consumption and preserving coagulation. In this study acute preoperatively performed plasmapheresis (APP) was investigated in cardiac surgery patients. Forty-five patients scheduled for elective aortocoronary bypass surgery were randomly divided into three groups of 15 patients each: 1) removal of platelet-poor plasma (PPP), 2) removal of platelet-rich plasma (PRP), and 3) no plasmapheresis (control group). Plasma volume removed was 10 ml/kg in all APP patients, and plasma was replaced by the same amount of low-molecular weight hydroxyethylstarch solution (6% HES 200/0.5). Various laboratory data were investigated before, during, and after extracorporeal circulation (ECC). Blood loss in control patients was more pronounced than in the two APP groups; two of the control patients needed packed red cells. APP itself did not affect coagulation variables, free hemoglobin, or polymorphonuclear (PMN) elastase. At the end of the operation, 5 h after ECC, and at the first postoperative day the number of platelets was significantly lower in the control group; PRP patients showed the highest values. Fibrinogen and AT-III levels were less compromised in APP patients than in the control group. Global coagulation parameters did not differ between the groups within the whole investigation period. PMN elastase increased significantly during ECC in all groups with the greatest increase in the control group (722%) and the smallest increase in PRP patients (280%), possibly due to the removal of cellular elements in this group.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Volume therapy with hypertonic saline hydroxyethyl starch solution in cardiac surgery.

The ideal solution for volume therapy remains controversial. In cardiac surgery, haemodynamic efficacy as well as the influence of extracorporeal oxygenation are of major interest when administering volume. The present study examines the effects of a new hypertonic saline hydroxyethyl starch solution in comparison to a 6% hydroxyethyl starch solution on haemodynamics and laboratory variables. Patients scheduled for elective aortocoronary bypass grafting received hypertonic saline hydroxyethyl starch (n = 10) or hydroxyethyl starch (n = 10) after induction of anaesthesia in order to double baseline pulmonary capillary wedge pressure. Ten patients without volume therapy served as a control group. Significantly less hypertonic solution than standard solution was effective in doubling pulmonary capillary wedge pressure. Fluid requirements in the patients who received the hypertonic solution were significantly less during, as well as after, cardiopulmonary bypas in comparison to those in the other groups. Cardiac index increased most in the patients who received the hypertonic solution (+34.8%), as did right ventricular end-diastolic volume. Patients in that group showed the highest decrease in total systemic resistance (-29.8%), whereas arterial pressure and right ventricular ejection fraction remained almost unchanged in all groups. No negative alteration in coagulation or organ function was demonstrated within the investigation period. It can be concluded that hypertonic saline hydroxyethyl starch solution seems to be a valuable alternative to conventional volume therapy in cardiac surgery.

Blood Volume↗
PubMed1990

RETRACTED: Efficacy of the phosphodiesterase inhibitor enoximone in complicated cardiac surgery.

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the request of the editor. In 2018, CHEST published a notice1 that all articles authored by Joachim Boldt be read with caution due to expressions of concern about falsified data. In 2020, CHEST received additional evidence of research misconduct and breaches of scientific integrity that were discovered following an investigation by the author's former institution, the University of Giessen2. In light of this new evidence, this article has been retracted by CHEST. 1. Irwin, R.S., MD, Master FCCP. Notice From the Editor in Chief. CHEST 153(3), p. 767. 2. Mukherjee, J. Statement on the scientific credibility of articles published by Joachim Boldt, formerly professor at Justus Liebig University (JLU), Giessen, Germany. https://ars.els-cdn.com/content/image/1-s2.0-S000709122030163X-mmc3.pdf.

Aged↗
PubMed1990

Drug interactions: the new phosphodiesterase inhibitor enoximone and the calcium channel blocker nifedipine in coronary surgery patients--influence on hemodynamics and plasma concentrations.

The calcium channel blocker nifedipine and the new phosphodiesterase (PDE) inhibitor enoximone are used in the treatment of cardiovascular diseases. Since both substances are acting on slow calcium channels and because systemic elimination of these two agents is dependent on oxidative drug metabolizing enzyme activity, this study was performed in order to investigate hemodynamic changes and effects on plasma levels when both substances are given simultaneously. Forty-five patients undergoing aortocoronary bypass grafting were randomly subdivided into three groups: (a) group (n = 15) received 0.3 micrograms/kg/min of nifedipine as an infusion (N patients); (b) group (n = 15) received 0.5 mg/kg of enoximone as a bolus (E patients); and (c) group (n = 15) received nifedipine and enoximone in the same dosages (E + N patients). In addition to various hemodynamic variables, plasma levels of nifedipine, enoximone, and enoximone sulfoxide were measured until the end of the operation. Injection of enoximone was followed by an increase in cardiac index and right ventricular ejection fraction, decrease in pulmonary artery pressure, pulmonary capillary pressure, and systemic vascular resistance, whereas heart rate and mean arterial pressure remained almost unchanged. These changes were comparable for E and E + N patients. Plasma concentrations of enoximone and enoximone sulfoxide were not affected by nifedipine infusion and showed a comparable course in E and E + N patients. Nifedipine plasma level dropped to values less than 15 ng/ml at the end of extracorporeal circulation in N and E + N patients. It can be concluded that enoximone improved hemodynamics even in patients pretreated with nifedipine.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

[The hemodynamic effects of various hydroxyethyl starch solutions in heart surgery patients].

Blood conservation is gaining more and more interest because of the increasing risks involved in homologous blood transfusions. Acute normovolemic hemodilution (ANH) is becoming an established technique even in cardiac surgery patients. The "optimal" kind of volume replacement, however, is still controversial. Thus, this study was carried out to investigate the hemodynamic response of 6 different hydroxyethyl starch (HES) solutions as volume replacement. METHODS. In 60 patients undergoing elective aortocoronary bypass surgery, acute, preoperative hemodilution was performed (10 ml/kg) and HES with different concentrations, molecular weight, and substitution was infused according to a randomized sequence: 1. 6% HES 450,000/0.7; 2. 10% HES 200,000/0.5; 3. 3% HES 200,000/0.5%; 4. 6% HES 40,000/0.5; 5. 6% HES 200,000/0.5; 6. 6% HES 200,000/0.62. All patients were monitored using a new pulmonary artery catheter that allows measurement of the right ventricular ejection fraction (RVEF), right ventricular enddiastolic volume (RVEDV), and right ventricular end systolic volume (RVESV) in addition to standard hemodynamic parameters. RESULTS. Immediately after finishing ANH the typical hemodynamic changes of hemodilution (HD) were apparent (decrease in peripheral resistance and increase in cardiac index (CI]. All 6 solutions investigated were effective in hemodynamic stabilization (no changes in mean arterial pressure (MAP), filling pressures (PCP, RAP), or heart rate (HR]. Forty min after ANH, however (before beginning extracorporeal circulation (ECC], there were significant differences between the groups: in groups 3 and 4 the increase in CI had already disappeared, and SVI in group 3 was even lower than the baseline values (-8%). In the other groups, a higher CI level remained even 40 min after ANH, which was most pronounced in groups 2 (+40%) and 5 (+43%). Right ventricular performance was not changed by ANH (RVEF unchanged in all groups). Forty min after hemodilution RVEDVI (-8%) and RVESVI (-16%) decreased significantly only in group 4, whereas in the other groups these parameters were still elevated. The most pronounced positive fluid balance after the end of ECC was found in group 4 (+850 ml); in these patients paO2 decreased significantly (-150 mmHg). CONCLUSIONS. The guarantee of stable hemodynamic conditions is a prerequisite when performing ANH in coronary surgery patients. The different physiochemical attributes of various HES solutions seem to be important, thus influencing their hemodynamic response. In this study, low-concentration (3% HES 200/0.5) and low-molecular (6% HES 40/0.5) HES solutions were less effective in stabilizing hemodynamics until the beginning of ECC. Additionally, their negative influence on fluid balance during ECC, followed by a deterioration in pulmonary function led to the conclusion that other solutions are preferable; in particular, 10% HES seems to be of advantage in these situations.

Coronary Artery Bypass↗
PubMed1990

[Hyperosmolar volume replacement in heart surgery].

The ideal solution for use in volume therapy is still a matter of debate. Hypertonic sodium (HS) solutions have been advocated for resuscitation from hemorrhagic shock (small volume resuscitation). As hypertonic fluids may also be of interest in cardiac surgery, the effects of a new HS solution were studied. METHODS. In 90 patients undergoing aorto-coronary bypass grafting studies were performed at three different periods: I (n = 30) after induction of anesthesia (before onset of the operation); II (n = 30) during cardiopulmonary bypass (CPB); III (n = 30) after termination of bypass. During these periods the patients were randomly allocated to one of three groups with 10 patients in each group: group 1 received a new hypertonic solution prepared in hydroxyethyl starch (HES) solution (72 g/l NaCl, 60 g/l HES, 2400 mosmol/l; HS-HES patients), group 2 received a 6% HES solution (200/0.5; HES patients), and group 3 received no volume infusion and served as controls. RESULTS. After the induction of anesthesia, significantly less HS-HES solution (4.5 +/- 0.5 ml/kg) than 6% HES solution (10.1 +/- 1.4 ml/kg) was necessary to double the baseline PCWP. The fluid balance during CPB was negative in the patients who had received HS-HES preoperatively (-0.03 +/- 0.01 ml/kg.min CPB), whereas 6% HES (+0.06 +/- 0.02 ml/kg.min CPB) and control patients (+0.13 +/- 0.03 ml/kg.min CPB) had a positive fluid balance. Both after the induction of anesthesia and after termination of bypass, CI increased more in the HS-HES group than in the HES patients, and it even decreased in the control group. SVR decreased in the HS-HES patients, whereas it increased in the control group. Rapid infusion of HS-HES during CPB was followed by a significant, but short-lasting decrease in MAP (-40 mmHg) and an increase in the oxygenator volume. Pulmonary gas exchange (= paO2) was least compromised in the HS-HES patients; the sodium concentration increased only in the HS-HES patients, but never exceeded 150 mmol/l. DISCUSSION. Cardiac surgery procedures offer a special situation for volume therapy as there is a possibility of deterioration in the macro- and microcirculation before, after, and during the period of CPB. Hemodynamic effects of the new HS-HES solution included an increase in CI and a decrease in SVR, which were not merely transient as has been reported which hypertonic saline solution used alone. It was also observed that HS-HES patients required significantly smaller volumes of fluids, both during CPB and during the early postoperative period. This effect seems to be due to a redistribution of interstitial fluid to the intravascular space, possibly decreasing tissue edema. CONCLUSION. The hypertonic saline HES solution adds a new dimension to volume therapy for cardiac surgery patients. The improvement in hemodynamics was effective and not only transient. Fluid requirements were significantly reduced during as well as after CPB, and pulmonary gas exchange was least compromised in these patients.

Aged↗
PubMed1990

[The hemodynamic effects of a treatment with beta-receptor blockers during coronary surgery. A comparison between acebutolol and esmolol].

UNLABELLED: Patients undergoing coronary artery bypass grafting are at risk for perioperative myocardial ischemia. Most such ischemic episodes occur without obvious hemodynamic changes. Tachycardia as a predictor for increased myocardial oxygen consumption doubles the incidence of myocardial ischemia when heart rate increases to over 110 beats/min. During the operative procedure for coronary revascularization, some maneuvers, e.g. intubation, sternotomy and mediastinal preparation, may be associated with tachycardia and increases in blood pressure despite an adequate level of anesthesia, so that the administration of beta-receptor blocking agents seems to be indicated. METHODS: The study included 20 patients undergoing elective aortocoronary bypass grafting. All patients developed tachycardia (heart rate greater than 100 beats/min) before the start of extracorporeal circulation. The hemodynamic effects of 0.1 mg/kg acebutolol given i.v. as a bolus over 30 s and hemodynamic effects of the ultrashort-acting esmolol by continuous infusion (loading dose 500 micrograms/kg over 1 min followed by a dose of 100 micrograms/kg per min) were randomly investigated. Anesthesia was maintained with fentanyl, midazolam and pancuronium bromide. All patients were invasively monitored by means of a pulmonary artery catheter. In addition, left ventricular pressure (LVP), left ventricular end diastolic pressure (LVEDP) and dp/dtmax were measured. RESULTS: Both acebutolol and esmolol, decreased the heart rate significantly (-24%, -27.5%), while the mean arterial pressure remained nearly unchanged. The cardiac index was diminished following acebutolol (-15.4%) and esmolol (-27.4%), while no significant change in stroke volume index was observed; systemic vascular resistance rose in all patients. Pulmonary artery pressure, PCP, PRA, LVP and LVEDP were unchanged, whereas dp/dtmax decreased both with acebutolol (-23.5%) and with esmolol (-36.5%). CONCLUSION: Both beta-receptor blockers--acebutolol and the ultrashort-acting esmolol--diminish heart rate sufficiently when tachycardia occurs during coronary artery bypass grafting. Reduction of heart rate is associated with a decrease of cardiac output and an impairment of myocardial contractility. From the hemodynamic point of view there is no major difference between the two beta-receptor blockers investigated, but esmolol may have an advantage over acebutolol because of its short elimination half-life.

Acebutolol↗
PubMed1990

Myocardial temperature during cardiac operations: influence on right ventricular function.

Maintenance of right heart integrity is frequently neglected during coronary operations. Right ventricular dysfunction sometimes limits the success of the surgical procedure, however. In addition to the use of cardioplegic solutions, myocardial hypothermia during ischemic cardiac arrest seems to be an important factor for guaranteeing right ventricular performance thereafter. This study was designed to measure myocardial temperature in patients with coronary artery disease who have significant stenosis of the right coronary artery in comparison with those who do not have stenosis of the right coronary artery and to evaluate the influence of myocardial temperature on right ventricular hemodynamics after cardiopulmonary bypass. Right ventricular function was assessed by thermodilution technique, which allows measurement of right ventricular ejection fraction, right ventricular end-diastolic volume, and right ventricular end-systolic volume. Right ventricular temperature differed significantly between the two groups, with the lowest value of 15.1 degrees +/- 1.8 degrees C in the group without stenosis of the right coronary artery and a value of 22.2 degrees +/- 2.1 degrees C in the group with stenosis of the right coronary artery. Left ventricular and septal temperatures were without group differences within the investigation period. Right ventricular hemodynamics were impaired only in the group with stenosis of the right coronary artery with a decrease in right ventricular ejection fraction from 44.2% to 34.1% immediately after termination of bypass and an increase in right ventricular end-diastolic volume index (+38%) and right ventricular end-systolic volume index (+70%). Cardiac index decreased only in this group, too (-22.5%). Analysis of covariance revealed a significant correlation only between changes in right ventricular ejection fraction, right ventricular end-diastolic volume, and right ventricular end-systolic volume and the course of right myocardial temperature. It is concluded that right ventricular hypothermia is more difficult to achieve in patients with a diseased right coronary artery. Constant myocardial hypothermia, however, seems to be important in guaranteeing right ventricular function, which easily can be evaluated by the thermodilution technique.

Body Temperature↗
PubMed1989

Characterization of cell surface polypeptides of unfertilized, fertilized, and protease-treated zona-free mouse eggs.

The polypeptide composition of unfertilized, fertilized, and protease-treated zona-free mouse eggs was evaluated in this study. Zona-free eggs were radioiodinated by an Iodogen-catalyzed reaction. Light microscopic autoradiography of egg sections revealed that labeling was restricted to the cell surface. Labeled eggs were solubilized, and cell surface polypeptides were identified by one-dimensional SDS polyacrylamide gel electrophoresis and autoradiography. The unfertilized egg demonstrated 8-10 peptides that incorporated 125I, with major bands observed at approximately 145-150, 94, and 23 kilodaltons (kD). Zona-free eggs fertilized in vitro and then radiolabeled demonstrated several new bands in comparison to unfertilized eggs, with a major band appearing at approximately 36 kD. Treatment of radiolabeled unfertilized eggs with either trypsin or chymotrypsin (1 mg/ml for 5-20 min) caused enzyme-specific modifications in labeled polypeptides. Trypsin (T) treatment resulted in time-dependant modification of the three major peptides at 145-150, 94, and 23 kD. Chymotrypsin (CT) treatment, in contrast, was associated with loss or modification of the 94 kD band, with no apparent effect on either the 145-150 or 23 kD band. Taken together with previous data indicating that T or CT egg treatment interferes with sperm-egg attachment and fusion (Boldt et al.: Biol Reprod 39:19-27, 1988), these results suggest a possible role for the 94 kD protein in sperm-egg interaction.

Animals↗
PubMed1989

Carbohydrate involvement in sperm-egg fusion in mice.

The potential involvement of cell-surface carbohydrates in sperm-egg fusion in mice was evaluated in this study. Zona-free mouse eggs were inseminated in the presence of a variety of simple saccharides to determine if certain sugars would act as competitive inhibitors of sperm-egg fusion. Of the sugars tested, L-fucose, galactose, and N-acetylglucosamine caused the greatest inhibition of sperm penetration levels relative to controls. A number of complex saccharides or glycoproteins with differing carbohydrate structures, including fucoidan, ascophyllan, ovomucoid, ovalbumin, fetuin, asialofetuin, and chondroitin sulfate, were also tested as competitive inhibitors of fusion. Only the L-fucose containing saccharides fucoidan and ascophyllan caused significant inhibition of fusion at concentrations of 0.05-1.0 mg/ml and 0.1-5.0 mg/ml, respectively. None of the other compounds tested had any inhibitory effect on fusion when tested at concentrations up to 5 mg/ml. The effect of the inhibitory saccharides was not due to the presence of residual zona material on the surface of the zona-free eggs, since zona-free eggs did not bind an 125I-labeled antibody directed against the ZP3 protein of the mouse zona pellucida. Pretreatment of either sperm or eggs with fucoidan (1 mg/ml) for 60 min prior to insemination caused only small decreases in sperm penetration levels, indicating that fucoidan exerted its major inhibitory effect on fusion only when present during insemination. Treatment of sperm, but not zona-free eggs, with fucosidase prior to insemination caused significant reductions in sperm penetration levels. Other glycosidic enzymes, including glucosidase, galactosidase, and N-acetylglucosaminidase, had no inhibitory effect on the sperm. These data suggest that an L-fucose component of the sperm surface is involved in sperm-egg fusion in the mouse.

Acetylglucosamine↗