GIK in cardiac surgery.
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Cardioplegic Solutions↗
Biomedical subjects
J Boldt
Publications and source records attributed to J Boldt.
Influence of different flow modi during extracorporeal circulation on endothelial-derived vasoactive substances.
Influences of shear stress on endothelin (ET) as well as prostacyclin (PGF) levels are common findings in different experimental settings. Thus, plasma levels of both substances seem to be a good tool to verify if different flow modi can be produced in blood vessels by generating pulsatile flow with a roller pump. In the present study, 20 patients scheduled for elective aortocoronary bypass operation were divided into two groups at random. One group was perfused with nonpulsatile (CON-group) and the other with pulsatile flow (PULS-group) during extracorporeal circulation. ET and PGF plasma levels were monitored perioperatively together with parameters of renal function and haemodynamic data. ET values were only slightly elevated at the end of extracorporeal circulation (mean baseline value; CON 3.1 pg/ml and PULS 3.2 pg/ml; mean maximal values at the end of cardiopulmonary bypass (CPB) 4.0 pg/ml and 3.9 pg/ml respectively). Prostacylin values (median baseline values: CON 56.7 pg/ml and PULS 57.1 pg/ml) peaked at the end of operation (median CON 117.8 pg/ml and PULS 137.5 pg/ml respectively) with a subsequent small decrease. No differences between the groups could be observed at any time point with respect to vasoactive substances, urine output (CON 6.5 ml/min and PULS 6.2 ml/min) or haemodynamics during CPB. This confirms studies emphasizing that no effective microvascular pulsatile flow is generated by conventional pulsatile flow-generating devices. In the present study, normothermia and a constant flow rate were maintained during CPB. Aortic cannulae (body-surface-related not maximal large diameters) were inserted. Altering these procedures may have led to more pronounced differences between the groups. All patients had an uneventful course after the operation. Similar to other reports, the present study was not able to demonstrate any benefit of pulsatile perfusion during extracorporeal circulation.
Aged↗
RETRACTED: Do plasma levels of circulating soluble adhesion molecules differ between surviving and nonsurviving critically ill patients?
This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal).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 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.
Adult↗
[Cerebral oximetry by infrared spectroscopy in comparison with continuous measurement of oxygen saturation of the jugular vein bulb in interventions of the internal carotid artery].
OBJECTIVE: Monitoring the central nervous system during carotid endarterectomy plays an important role in detection of cerebral ischemia. With optical spectroscopy in the near-infrared light range it is now possible to measure regional cerebral oxygen saturation (rSO2) noninvasively. Numerous studies emphasize the importance of cerebral oxygen balance rather than absolute values of cerebral blood flow or metabolic rate. In this study data from oxygen saturation measured in the jugular bulb (SJO2) were compared to rSO2. METHODS: 10 patients undergoing elective carotid end-arterectomy were enrolled after written informed consent and approval by the local ethics committee. rSO2 data were measured by cerebral spectroscopy (INVOS 3100, Somanetics, Michigan/USA). To avoid lesions of the internal carotid artery, a 4-F oxymetry catheter (OPTICATH, Abbot GmbH, Wiesbaden) was placed in the jugular bulb by retrograde approach after preparation by the surgeon. Anaesthesia and mechanical ventilation were standardised. RESULTS: After cross-clamping of the internal carotid artery rSO2 significantly decreased (60.5 +/- 3.5%) compared to baseline (66.0 +/- 1.4%). After declamping rSO2 increased significantly (63.0 +/- 4.2%) and was close to baseline at the end of operation (65.0 +/- 2.8%). The SJO2 time course showed good correlation compared to rSO2 data (r = 0.85). After cross-clamping SJO2 decreased significantly (51.5 +/- 6.3%) in comparison to baseline (59.5 +/- 4.9%). Declamping increased SJO2 to 59.5 +/- 6.3%. No changes in latencies or amplitudes of SEP were observed throughout the operation. CONCLUSIONS: Noninvasive cerebral optical spectroscopy is a useful tool to determine the brain tissue oxygenation. The positive correlation to jugular bulb oxygen saturation is somewhat unexpected as rSO2 evaluates regional while SJO2 measures global oxygen content. However our results suggests that both methods are able to detect episodes of cerebral ischemia during carotid endarterectomy. The interpretation of the changes of cerebral oxygen saturation with respect to neurological outcome warrants further studies.
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[Optimization of ventricular function during anesthesia induction by administering crystalloids and colloids to heart surgery patients].
OBJECTIVE: To describe the changes in cardiac function after administration of three different solutions infused after anesthetic induction. PATIENTS AND METHODS: Thirty-six patients scheduled for elective aortocoronary bypass surgery were randomly distributed into three groups. Over a period of 25 min after anesthetic induction, 12 received 10 ml/kg of Ringer solution (low dose crystalloid group), 12 received 20 ml/kg of Ringer solution (high dose crystalloid group), and 12 received 10 ml/kg of Ringer solution with 10 ml/kg of hydroxi-ethyl-almidon solution 450,000 D, 0.7 substitution grade (group C-HEA). Minute volume, systemic and pulmonary pressures, osmolality of blood and urine, and plasma and urine sodium concentrations were measured before and after infusion of the assigned liquid. RESULTS: In spite of the volume infused, low dose crystalloid group showed a high incidence of oliguria, increased urinary osmolality and decreased sodium in urine. Cardiac and systolic indices and left ventricular work load remained stable after infusion of the assigned liquid in low and high dose crystalloid groups, whereas they increased significantly ion group C-HEA (+23%, +16% and +20%). CONCLUSION: Administration of restricted doses of crystalloids after anesthetic induction favors the retention of water and sodium. Higher doses of crystalloids weaken this effect. However, neither of these two regimens leads to a more effective cardiac work load. A combination of crystalloids and colloids administered immediately after anesthetic induction temporarily improves cardiac performance during surgery.
Aged↗
Thrombomodulin in pediatric cardiac surgery.
In 30 consecutive children with congenital heart disease scheduled for pediatric cardiac operations, thrombomodulin, protein C, free protein S, and thrombin-antithrombin complex were measured by enzyme-linked immunosorbent assay after the induction of anesthesia (baseline value), and then before, during, and after cardiopulmonary bypass until the first postoperative day. The patients were divided prospectively into two groups: children weighing less than 10 kg (group 1; n = 15) and those weighing more than 10 kg (group 2; n = 15). At baseline, the plasma concentration of thrombomodulin was significantly higher in the children in group 1 than in those in group 2 (83.1 +/- 11.0 ng/mL versus 29.2 +/- 12.1 ng/mL). During cardiopulmonary bypass, the thrombomodulin level was reduced in both groups without showing any significant group differences. Five hours after cardiopulmonary bypass and on the first postoperative day, the thrombomodulin level exceeded normal values only in the children weighing less than 10 kg. In both groups, the protein C levels were already below normal at the beginning of the study. The baseline protein S concentration was higher in the smaller children (80% +/- 18%) than in the larger children (66% +/- 11%). It was reduced by cardiopulmonary bypass in both groups; however, postoperatively it did not return to normal in group 1 (45.1% +/- 10%). Plasma levels of the thrombin-antithrombin complex were similar in both groups, with a marked increase at the end of cardiopulmonary bypass, and returned to near-normal levels by 5 hours after bypass.(ABSTRACT TRUNCATED AT 250 WORDS)
Antithrombin III↗
RETRACTED: Does aprotinin influence endothelial-associated coagulation in cardiac surgery?
Aprotinin has been reported to reduce bleeding in cardiac surgery patients. Its mechanisms of action on coagulation have not been fully elucidated. In a prospectively randomized study of 40 patients undergoing elective aortocoronary bypass grafting, the influence of high-dose aprotinin (2 million IU of aprotinin before CPB, 500,000 IU/h until the end of operation, 2 million IU added to the prime) (N = 20) on endothelial-related coagulation was compared to a nontreated control group (N = 20). Thrombomodulin (TM), protein C and (free) protein S as well as thrombin/antithrombin-III (TAT) plasma concentrations were measured by enzyme-linked immunosorbent assays (ELISA) before the aprotinin infusion, before cardiopulmonary bypass (CPB), during CPB and after CPB, at the end of surgery, 5 hours after CPB, and on the first postoperative day. All standard coagulation parameters (AT-III and fibrinogen plasma levels, platelet count, partial thromboplastin time) did not differ between the two groups. At baseline, TM plasma levels were within the normal range (< 40 ng/mL) and similar in both groups. During CPB, TM plasma concentrations decreased similarly in both groups (aprotinin: 18 +/- 6 ng/mL, control: 17 +/- 7 ng/mL) followed by a comparable increase in the postbypass period until the first postoperative day (aprotinin: 60 +/- 10 ng/mL, control: 53 +/- 11 ng/mL). Protein C and (free) protein S plasma levels also showed no differences between the two groups. On the first postoperative day, baseline values for protein C and protein S had not yet been reached.(ABSTRACT TRUNCATED AT 250 WORDS)
Antithrombin III↗
RETRACTED: Volume loading with hypertonic saline solution: endocrinologic and circulatory responses.
Hypertonic saline solution appears to be an attractive method of volume expansion. In 45 patients undergoing elective aorto-coronary bypass grafting, endocrinologic and circulatory responses to volume loading with hypertonic saline solution prepared in low molecular weight (MW) hydroxyethyl starch (HES) solution (72 g/L NaCl, HES concentration: 6%; MW: 200,000 D; degree of substitution [DS]: 0.5) (HS-HES) was compared randomly to patients who had received low molecular weight HES solution (LMW-HES). A group of patients without volume loading served as a control. Volume was infused to double the low pulmonary capillary wedge pressure (PCWP < 5 mmHg) after induction of anesthesia. Plasma levels of atrial natriuretic peptide (ANP), endothelin, vasopressin, and catecholamines were measured before, during, and after cardiopulmonary bypass (CPB) until the first postoperative day. In addition to systemic circulatory changes, capillary skin blood flow was measured by laser Doppler flowmetry. ANP plasma concentration increased in both volume groups (HS-HES: +79%; HES: +32%), whereas it decreased in the control (-20%). Infusion of HS-HES resulted in an increase in plasma endothelin concentration before and after CPB (from 3 to 6 pg/mL). Five hours after CPB, both treatment groups had higher endothelin plasma concentrations than the control patients (P < 0.05). Epinephrine and norepinephrine plasma levels increased most markedly in the control patients and were highest in the postbypass period in these patients. CI increased most after infusion of HS-HES (+65%) (P < 0.05). In the postbypass period, CI remained significantly higher in both volume groups than in the controls.(ABSTRACT TRUNCATED AT 250 WORDS)
Atrial Natriuretic Factor↗
[Topographic changes in cerebral electric activity after premedication with flunitrazepam].
AIM: The effects on cerebral function of premedication with the benzodiazepine flunitrazepam and with morphine were studied on the evening of the preoperative day (2 mg flunitrazepam p.o.) and 90 minutes before induction of anaesthesia (2 mg flunitrazepam plus 15 mg morphine i.m.). DESIGN: The EEG was analysed topographically (17 electrodes) and quantitatively. RESULTS: As a typical effect of benzodiazepines, increases in electrical activity in the frequency band beta-1 of the power spectrum were observed, and could be demonstrated 10 minutes after oral application, mainly in the frontal and central parts of the cortex. Increases in the powerbands delta and theta indicated induction of sleep approximately 15-20 minutes after application and were not looked upon as an effect of the benzodiazepine exclusively. These increases were noticed first in the central, occipital and temporal areas and after 30 minutes in the frontal parts of the cortex. Flunitrazepam plus morphine showed qualitatively similar but quantitatively less pronounced results. Topographical differences were similar to the results of an application of flunitrazepam alone. DISCUSSION: The results demonstrate the importance of a topographical as well as quantitative evaluation in studies on complex interactions of sedative or narcotic drugs and their clinical effects on cerebral function.
Administration, Oral↗
[The pulmonary capillary wedge pressure reflects the preload of the left ventricle--fact or fiction?].
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Cardiac Catheterization↗
[Lymphocyte subpopulations in controlled hypotension with sodium nitroprusside].
AIM: Induced hypotension is an anaesthesiological method to reduce blood loss in surgical patients. The aim of this study was to investigate whether induced hypotension with sodium nitroprusside (SNP) causes changes in lymphocyte subpopulations. METHODS: In a prospective randomised evaluation 30 patients undergoing elective oto-rhino-laryngological interventions were studied. In 15 patients SNP was administered to reduce the mean arterial pressure to 50 mmHg. There was a control group of another 15 patients. Anaesthesia was induced with etomidate and maintained with isoflurane. At 7 a.m. on the day of operation (T1), 10 minutes after induction of anaesthesia (T2), 60 minutes after T2 (T3, end of SNP-infusion), 120 minutes (T4) after T2; 180 minutes (T5) after T2, and at 7 a.m. on the following morning (T6) blood samples were taken. A new method (whole blood) was used to mark 6 different lymphocyte subpopulations with monoclonal antibodies which were measured by flow cytometry. RESULTS: In both groups a significant decrease in total lymphocyte count (from 32.7 x 10(9) cells/l preoperatively to 13 x 10(9) cells/l the following morning in the SNP-group and from 31 x 10(9) cells/l to 14.2 x 10(9) cells/l the following morning in the control group) was observed. In the SNP-group the HLA-DR positive T-lymphocytes increased from 11.8% at T1 to 19.2% at T5 and 22.3% at T6. No statistically significant changes were found in percentage of T-, T4-, T8-, B-lymphocytes and natural killer cells. CONCLUSION: The increase in the percentage of activated T-lymphocytes is possibly due to an activation of the sympatho-adrenergic system after sodium nitroprusside-infusion and a subsequent redistribution of these cells from other organs (bone marrow, spleen, lymph nodes). The cell-mediated and the humoral immunity are not altered by induced hypotension. In discussing this result, the age of the patients, the extent of the surgical trauma, the anaesthesiological procedure and the methodological aspects in the lymphocyte assay should be taken into consideration.
Adolescent↗
Influence of different anticoagulation regimens on platelet function during cardiac surgery.
Qualitative platelet defects are of great importance as a cause of bleeding in cardiac surgery. We have studied the effects of different anticoagulation regimens on platelet function in 60 patients undergoing elective aorto-coronary bypass grafting with cardiopulmonary bypass (CPB). Patients were allocated randomly to four groups (each group n = 15) to receive either: bovine heparin 300 u. kg-1 (standard); heparin 300 u. kg-1 followed by a continuous infusion of 10,000 u. kg-1 until the end of CPB; heparin 600 u. kg-1; or heparin 600 u. kg-1 in addition to high-dose aprotinin 2 million iu before CPB, 500,000 iu h-1 until the end of operation and 2 million iu added to the prime. Platelet function was evaluated by aggregometry (turbidometric technique) using adenosine triphosphate (ADP) 2.0 mumol litre-1, collagen 4 microliters ml-1, adrenaline 25 mumol litre-1 and saline solution (control) as inducers. Both maximum aggregation and maximum gradient of aggregation were measured in arterial blood samples before, during and after CPB until the first day after operation. Mean total dose of heparin given in groups 2, 3 and 4 was more than 50,000 u. and differed significantly from that of group 1 (28,150 (SD 4700)u.). Platelet aggregation variables were most depressed during CPB and until the end of surgery in groups 2 and 3 (maximum aggregation - 54% to - 75% of baseline values). In the postoperative period, platelet function recovered but did not completely reach baseline values in these patients.(ABSTRACT TRUNCATED AT 250 WORDS)
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Cardiopulmonary actions of intravenously administered enalaprilat in trauma patients.
OBJECTIVE: To determine the cardiopulmonary actions of the intravenous administration of the angiotensin-converting enzyme inhibitor enalaprilat in hypertensive trauma patients. DESIGN: Prospective, before/after trial. SETTING: Intensive care unit (ICU) of a university hospital. PATIENTS: Twenty critically injured and hypertensive ICU patients. All patients were receiving continuous sedation (fentanyl and midazolam) for at least 2 days before the injection of enalaprilat and had a mean arterial pressure (MAP) of > 95 mm Hg. "Responders" were defined as having a decrease in MAP of > 15% within 30 mins after enalaprilat injection. INTERVENTIONS: Intravenous administration of 0.06 mg/kg of the angiotensin-converting enzyme inhibitor enalaprilat. Repeated doses were given when no sufficient response (decrease of MAP of > 15% within 30 mins after injection) was seen ("nonresponders"). MEASUREMENTS: In addition to standard hemodynamic monitoring, right ventricular hemodynamics and oximetric variables were also documented. Measurements were carried out before enalaprilat injection (during hemodynamic steady state [baseline values]) and at 1, 5, 10, 20, 30, 60, and 120 mins after enalaprilat administration. MAIN RESULTS: MAP was successfully controlled in 17 of 20 patients (maximum decrease -27 mm Hg [-26%]). In the three other patients, even reinjection of enalaprilat (0.06 mg/kg) did not sufficiently reduce MAP. In the 17 responders, heart rate did not increase, whereas central venous pressure, pulmonary arterial pressure, and pulmonary artery occlusion pressure decreased significantly after intravenous administration of enalaprilat. Cardiac index changed only slightly (mean maximum +0.70 L/min/m2 [+18%]). Right ventricular ejection fraction increased from 36% to 45% (p < .05); right ventricular end-diastolic and end-systolic volume index decreased significantly. Both systemic and pulmonary vascular resistance indices decreased within the investigation period (-31% and -16%, respectively). Pao2/FIO2, intrapulmonary right-to-left shunting, and oxygen extraction ratio were not altered. Oxygen delivery index (+17%) and oxygen consumption index (+20%) increased during the investigation period (p < .04). CONCLUSIONS: The intravenous administration of enalaprilat successfully decreased blood pressure in most of our patients. Mechanisms other than the renin-angiotensin system also appear to be involved in hypertensive, critically ill patients. Pulmonary function was not altered; right ventricular function, and both oxygen consumption and oxygen delivery improved in the enalaprilat responder group. Thus, the availability of intravenous enalaprilat seems to enlarge our armamentarium for treating hypertension in the critically ill patient.
Acute Disease↗
Continuous hemofiltration and platelet function in critically ill patients.
OBJECTIVE: To evaluate platelet function in patients undergoing continuous pump-driven veno-venous hemofiltration. DESIGN: Prospective study. SETTING: Surgical intensive care unit of a university hospital. PATIENTS: Twenty consecutive, critically ill patients with acute renal failure (serum creatinine concentration > 3.0 mg/dL (> 265 mumol/L), serum urea > 200 mg/dL (> 33 mmol/L), urine output < 20 mL/hr) secondary to sepsis or trauma. A comparable group (n = 20) without renal failure and not undergoing hemofiltration served as a control group. INTERVENTIONS: Continuous pump-driven veno-venous hemofiltration was used in patients with renal insufficiency. Pump flow ranged from 60 to 100 mL/hr. MEASUREMENTS AND MAIN RESULTS: Platelet function was assessed by a turbidimetric technique using a double-channel aggregometer. Aggregation was induced by adenosine diphosphate (ADP) (2.0 mumol/L), collagen (4 micrograms/mL), epinephrine (25 mumol/L), and saline solution (control). Maximum aggregation was considered to be the maximum increase in light transmission after the addition of the aggregating agents. The maximum gradient of aggregation was considered to be the maximum increase per minute. Measurements were carried out before hemofiltration (baseline values) and during the following 5 days. In the control group, blood samples were taken at corresponding data points. Eight patients undergoing continuous hemofiltration survived during the investigation period; 16 patients in the control group survived. There were no significant differences among the two groups with respect to standard coagulation variables. Maximum platelet aggregation was lower than in normal patients after the addition of all three inductors (ADP, collagen, and epinephrine). In control patients, all aggregation variables remained almost stable during the entire investigation period. In the hemofiltered patients, maximum platelet aggregation was significantly reduced (ADP, decrease of 62 relative % from baseline values; collagen, decrease of 86 relative % from baseline values; epinephrine, decrease of 77 relative % from baseline values). Maximum platelet aggregation was also depressed in these patients (ADP, decrease of 40 relative % from baseline values; collagen, decrease of 88 relative % from baseline values; epinephrine, decrease of 85 relative % from baseline values). When platelet aggregation variables were reduced greater than a decrease of 60 relative % from baseline values (in all induction groups), the mortality rate was 100%. CONCLUSIONS: Continuous pump-driven veno-venous hemofiltration significantly changed platelet aggregability, which became obvious 2 to 3 days after the start of hemofiltration.
Acute Kidney Injury↗
Changes in regulators of circulation in patients undergoing continuous pump-driven veno-venous hemofiltration.
Continuous pump-driven veno-venous hemofiltration (CVVH) has become an established method for treatment of acute renal failure (ARF). Since severe disturbances of (micro-) circulation are intimately involved in the bad outcome of these patients, the profile of endocrinological regulators of circulation was prospectively and serially measured in patients undergoing pump-driven CVVH (n = 15). 15 patients with similar APACHE II score, but without ARF and without CVVH were also studied. Endothelin-1 (ET-1), atrial natriuretic peptide (ANP), vasopressin, renin, and catecholamine (epinephrine, norepinephrine) plasma levels were measured before start of CVVH (= "baseline") (in the non-CVVH patients: admission to intensive care unit) and during the next 5 days. Various hemodynamic parameters were additionally monitored. MAP, HR, PAP, CI, and right ventricular hemodynamics (RVEF, RVEDV, RVESV) remained almost unchanged in the CVVH patients and were without differences to the non-CVVH group within the entire investigation period. PCWP and RAP were higher in the CVVH patients already at baseline (RAP, 17.8 +/- 4.0 mmHg; PCWP, 22.1 +/- 4.5 mmHg) (p < .02) and remained elevated in the further course of the investigation. Renin plasma level was higher already at baseline in the CVVH patients (907 +/- 184 pg/ml) (p < .05) and further increased during CVVH (to 1453 +/- 186 pg/mL). Vasopressin increased only in the CVVH group (from 3.80 +/- .66 to 11.85 +/- 1.05 pg/mL) (p < .01).(ABSTRACT TRUNCATED AT 250 WORDS)
Acute Kidney Injury↗
Isolated circulatory response to intravenous administration of the ACE inhibitor enalaprilat.
The isolated vascular effects of intravenous administration of the angiotensin converting enzyme (ACE) inhibitor enalaprilat were investigated. Thirty male patients undergoing cardiopulmonary bypass (CPB) were studied. According to a randomized sequence, 0.04 mg kg-1 enalaprilat (low-dose, n = 10), 0.08 mg kg-1 (high-dose, n = 10) enalaprilat or saline solution as placebo (control group, n = 10) was given as an i.v. bolus during CPB. Changes in mean arterial pressure (MAP) and venous reservoir (RV) of the extracorporeal circulation were studied as indices of arterial resistance and venous capacitance. Mean arterial blood pressure (MAP) and peripheral vascular resistance (SVR) were significantly more reduced in the high-dose enalaprilat group (MAP: -36 mm Hg after 9 min; SVR: -836 dyn s cm-5) than in the low-dose group (MAP: -13 mm Hg after 10 min). Volume of the reservoir (RV) decreased in both enalaprilat treated groups indicating additional (dose-dependent) venous pooling effects of the substance (low-dose: -300 ml; high-dose: -520 ml; control group: -100 ml). Skin capillary blood flow measured by laser Doppler flowmetry (LDF) increased after injection of 0.04 mg kg-1 enalaprilat, whereas it decreased significantly when MAP fell markedly in patients treated with high-dose enalaprilat. I.v. enalaprilat had dose-dependent vasodilating properties in the arterial and venous vessel system indicating reduction in pre- and afterload. Microcirculation in both enalaprilat treated groups improved as long as reduction in blood pressure was not limited.
Blood Pressure↗
Retracted: Influence of volume replacement with different HES-solutions on microcirculatory blood flow in cardiac surgery.
A variety of hydroxyethyl starch HES preparations with different molecular weight average (Mw) and molar substitution (MS) is available for volume replacement during acute normovolemic haemodilution (ANH). Particularly with regard to microcirculation, the ideal solution for volume therapy has not been found. The influence of four different HES preparations on macro- and microcirculation was investigated in 40 patients scheduled for elective aorto-coronary bypass grafting and undergoing ANH (preoperative withdrawn blood: 10 ml.kg-1): 1) 6% HES with Mw of 450,000 dalton and MS of 0.7; 2) 6% HES with Mw of 200,000 dalton and MS of 0.5; 3) 6% HES with Mw of 200,000 dalton and MS of 0.62; 4) 6% HES with Mw of 40,000 dalton and MS of 0.5. A 5th group without ANH served as a control (10 patients in each group). In addition to systemic haemodynamics and various laboratory parameters, skin capillary blood flow was measured by laser Doppler flowmetry. Laser Doppler flow (LDF) was monitored simultaneously at the patient's forehead and forearm. Changes in systemic haemodynamics were similar in all ANH-patients. Systemic vascular resistance (SVR) was lowest after infusion of HES 200/0.5. The most pronounced increase in plasma viscosity was in patients of group 1 (450/0.7) (P < 0.05) and plasma viscosity remained highest during the entire investigation period in these patients. After ANH, skin capillary blood flow measured at the forehead decreased in all patients except in patients of group 2 (200/0.5: max. +18%). Group 3 (200/0.62) showed the highest decrease in forehead-LDF. During CPB, forehead-LDF decreased significantly in groups 3 (200/0.62) and 4 (40/0.5).(ABSTRACT TRUNCATED AT 250 WORDS)
Blood Circulation↗
Cold or warm start of cardiopulmonary bypass--influence on microcirculatory blood flow.
In a randomized study of 30 patients undergoing elective aortocoronary bypass grafting, either cold start of cardiopulmonary bypass (CPB) (prime: room temperature [approximately 20 degrees C], n = 15) or normothermic start of CPB (prime: warmed up to the patients' blood temperature, n = 15) were performed. After warm start, CPB was continued using almost normothermia (lowest nasopharyngeal temperature: 35.8 +/- 0.4 degrees C), after cold start hypothermia was used (lowest nasopharyngeal temperature: 28.8 +/- 0.2 degrees C). Changes in microcirculatory perfusion were assessed by measuring skin capillary blood flow at the patient's forearm and forehead using laser Doppler technique. Laser Doppler flow (LDF) was continuously monitored before onset of CPB (= baseline values), 30 seconds, one, five, 10, 15 and 20 minutes after start of CPB. Mean arterial blood pressure (MAP) and systemic vascular resistance (SVR) were reduced by CPB in both groups, with the more pronounced reduction in the normothermic patients. Haemoglobin and plasma viscosity were without differences between the groups. The lowest blood temperature in the hypothermic patients was 21.0 +/- 0.3 degrees C, and the lowest rectal temperature in these patients was 29.0 +/- 0.3 degrees C (20 minutes after start of CPB). Forehead- and forearm-LDF increased significantly in both groups by start of CPB. In the hypothermic patients, this increase was significantly lower, and LDFs were already reduced below baseline values five to 10 minutes after onset of CPB (LDF-forehead -18%, LDF-forearm -72%).(ABSTRACT TRUNCATED AT 250 WORDS)
Aged↗