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Objective: Evaluation of hemodynamic effects of S-(+)-ketamine versus ketamine-racemic mixture during induction of anesthesia, during steady-state of a fentanyl-midazolam-anesthesia and in the period of aortic cross-clamping during extracorporeal circulation., Patients: 80 patients scheduled for coronary revascularization., Study Design: double-blind, randomized., Study 1: Induction of anesthesia with ketamine-racemic mixture (3 mg/kg) or S-(+)-ketamine (1.5 mg/kg) plus midazolam 0.15 mg/kg., Parameters: invasive hemodynamic monitoring including right ventricular volumes and pressure. STUDY 2: Bolus of ketamine-racemic mixture (3 mg/kg), S-(+)-ketamine (1.5 mg/kg) or placebo during steady-state anesthesia with fentanyl and midazolam., Parameters: see study 1, additionally left ventricular systolic and end-diastolic pressure and maximum speed of left ventricular pressure increase (dp/dt). STUDY 3: Bolus of ketamine-racemic mixture (3 mg/kg), S-(+)-ketamine (1.5 mg/kg) or placebo in the period of aortic cross clamping during ECC., Parameters: mean systemic pressure, central venous pressure, reservoir volume., Study 1: Heart rate and systemic blond pressure remained unchanged until intubation, which caused significant increases of these parameters. Stroke volume Index and cardiac index decreased in the S-(+)-group compared with racemic mixture, right- and left ventricular filling parameters remained unchanged throughout the study. STUDY 2: There were no significant hemodynamic changes with time or between the groups. STUDY 3: Significant arterial vasodilation was observed in the racemic mixture group, venous parameters remained unchanged., Conclusion: There were no major differences in the hemodynamic profiles of S-(+)-ketamine and the racemic mixture. S(+)-ketamine did not provide hemodynamic advantages. The use of both preparations should be limited to selected clinical situations in patients with reduced coronary reserve.

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.

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.

In two groups of ten patients each (group I: myocardial insufficiency, group II: no myocardial insufficiency) during anaesthesia arterial plasma levels of lidocaine were studied, following iv bolus administration (1 mg./kg. bw) and subsequent lidocaine infusion (2 mg./min.) for 15 minutes. With this dosage, recommended for antiarrhythmic therapy, plasma levels exceeded the therapeutic range in group I and in some patients reached almost toxic levels (10 micrograms./ml.). In group II lidocaine plasma levels were within the therapeutic range (1,5-4 micrograms./ml.). In patients with myocardial insufficiency and/or reduced hepatic metabolism antiarrhythmic therapy with lidocaine has to be performed with significantly reduced dosages; drug monitoring is recommended.

Interest in preoperative hemodilution (HD) has intensified perceptibly again, because of the increasing risk of adverse reactions to donor blood. However, in coronary surgery patients the use of HD is still the subject of controversy, as it may possibly influence organ function and especially lung water content. New techniques, including membrane oxygenation, extracorporeal circulation (ECC) with only "partial" bypass due to 2-stage cannulation, and hemoconcentration with cell separators, have significantly modified patient management in the field of cardiac surgery. Therefore, the influence of moderate hemodilution (12 ml/kg) on extravascular lung water (EVLW) was investigated under these conditions in 45 patients with coronary artery disease. Volume replacement was performed either with hydroxyethyl starch solution (HD-HES group, n = 15, ratio of replacement 1:1) or with Ringer's lactate (HD-RL-group, n = 15, ratio 2.5:1); 15 patients not subjected to HD served as controls. ECC was carried out with membrane oxygenators only in partial bypass. Both during and after ECC, blood was concentrated by means of a cell-saving system allowing separation and reinfusion of the red cells while the plasma is discarded. EVLW was measured using a double-indicator dilution technique with indocyanine green. Starting from comparable baseline values, EVLW was not significantly changed by hemodilution. After ECC, however, the HD-RL group showed a significant increase in lung water content (means: +2.49 ml/kg equal 42.6%), whereas this was not significantly changed in the other groups. By 5 h after ECC, the lung water content had returned to baseline values and no more differences could be observed between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

In a prospective, randomized double-blind study the hemodynamic and respiratory effects of i.v. meptazinol, a new synthetic narcotic agonist-antagonist analgesic given in 2 dosages (2 mg/kg and 4 mg/kg), were compared over 15 min to a control group that received 0.9% saline solution as placebo. In a total of 80 patients scheduled for elective aortocoronary bypass surgery, the study was performed before and during general anesthesia and during extracorporeal circulation (ECC). A dose-dependent increase in mean arterial pressure (MAP) and total systemic resistance (TSR) were the predominant hemodynamic effects of meptazinol before and during anaesthesia (Tables 1 and 2). Within the study period no change in heart rate (HR) or cardiac index (CI) could be observed. Directly measured left ventricular parameters revealed a significant increase in left ventricular pressure (LVEDP, and dp/dtmax (Fig. 1). During ECC meptazinol injection was followed by a dose-dependent increase in perfusion pressure, indicating a direct vasoconstrictive effect; no influence on the capacitance system ("venous pooling") could be observed (Fig. 2). In the spontaneously breathing, premedicated patients (morphine hydrochloride 0.15 mg/kg and flunitrazepam 0.03 mg/kg) paO2 increased and paCO2 decreased, especially after injection of the higher dosage of meptazinol; there was no influence on intrapulmonary right-to-left shunting (Qs/Qt).(ABSTRACT TRUNCATED AT 250 WORDS)

Haemoseparation is used for recovery of autologous blood following cardiac surgery protecting patients from various hazards accompanying homologous blood transfusion. Former studies demonstrated that autotransfusion did not increase blood loss after cardiac surgery despite reduced plasma and platelets following centrifugation and washing of oxygenator content. The purpose of our study was to determine the content of heparin and unbound haemoglobin in autologous packed red cells. METHODS. 10 consenting patients undergoing cardiac surgery (table 1) were investigated. Immediately after termination of bypass blood samples were collected from the oxygenator and from autologous blood following concentration and washing with saline solution in the Haemonetics Cell-Saver 4. Contents of haemoglobin, haematocrit, heparin - with and without addition of antithrombine III - and unbound haemoglobin were analysed. RESULTS. Mean duration of extracorporeal circulation was 100.4 minutes. The oxygenators' volume averaged 2089.9 ml blood with a haemoglobin content of 6.7 g/dl and a haematocrit of 20.4%. This was reduced to 660.8 ml autologous blood with a haemoglobin content of 17.9 g/dl and a haematocrit of 57.2% (table 2). The heparin content of the oxygenator blood was 0.47 U/ml without AT III, and with AT III 0.87 U/ml. Autologous blood contained 0.009 U/ml without AT III; with AT III we measured 0.41 U/ml heparin. Unbound haemoglobin content amounted to 11.4 mg/dl in the oxygenator blood and 71.8 mg/dl in the autologous blood (table 3). CONCLUSIONS. Our results demonstrate that autologous blood following concentration and washing of the oxygenator blood with a Haemonetics Cell-Saver 4 contains heparin, but the amount of heparin is not enough to provoke bleeding after retransfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

To investigate the importance of amino acid infusions in immediate postoperative parenteral nutrition, cardiac patients were randomly allocated into two groups. Applicating identical carbohydrate calories (2000 kcal/day) group 1 received only essential amino acids while in group 2 a combined pattern of essential and non essential amino acids was infused. In addition to routine laboratory data several parameters of protein metabolism including nitrogen balance were evaluated. Although nitrogen balance was positive only in group 2 the differences between the two groups concerning other parameters measured were minimal. The different infusion regimes are discussed revealing the significance of additional parenteral nutrition in these patients.

Several studies have demonstrated that preoperative withdrawal and storage of autologous plasma as fresh frozen plasma is effective in blood conservation. For that purpose patients with elective surgery (orthopaedic surgery, open heart surgery, neurosurgery and others) have to undergo donor plasmapheresis without staying in the hospital. Depending upon the need the procedure can be performed several times preoperatively, taking about 900 ml in a normal weighting subject at once. The collection of autologous plasma should be finished at least 14 days before surgery. In order to investigate the haemodynamic effects of donor plasmapheresis 30 patients scheduled for coronary bypass surgery were devided into two groups. 15 patients underwent plasmapheresis (10 ml plasma/kgbw) by one-needle-technique using a Haemonetics seperator (PCS) after premedication but before onset of anaesthesia. Blood withdrawal was performed with 0.5 ml/kgbw x min. Another 15 patients, serving as control had no plasma withdrawal and were measured at identical times as the other group. Both groups had an identical fluid replacement with 500 ml Ringer's solution during the investigation period. Plasma withdrawn was not substituted by colloidal solution (simulating the situation when plasmapheresis is performed at the outpatient). Haemodynamic measurements (both groups) included heart rate, arterial blood pressure, right- and left-atrial pressure, systemic- and pulmonary-vascular resistance and cardiac output. There were no relevant effects of plasmapheresis on haemodynamic function during and after the investigation period in that patients: neither heart rate, blood pressure or vascular resistance changed significantly nor did pre- and afterload or cardiac index. No differences to the group without plasmapheresis could be observed.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

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.

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.

With regard to Starling's equation, two factors are important for fluid regulation in pulmonary tissue: colloid osmotic pressure (COP) and hydrostatic pressure (PCP). The purpose of the study was to evaluate the relationship between COP, COP-PCP-gradient and extravascular lung water (EVLW) immediately after extracorporeal circulation (ECC). 39 consenting patients undergoing elective aorto-coronary bypass surgery received 1000 ml washed erythrocytes (w.e.; cell saver) +400 ml fresh frozen plasma (FFP) after ECC. Additionally, group I (n = 15) received 300 ml albumin 20%, group II (n = 13) 500 ml plasmaexpander (3% HES 200/0.5) and group III (n = 11) no more volume. At three different times, measurement of EVLW was performed by using double-indicator-dilution technique with indocyanine green and a microprocessed lung water computer: 15 minutes after ECC (before infusion), 45 minutes after ECC (after infusion), five hours after ECC. Application of 20% albumin led to a significant increase in COP (+67%) which was less pronounced in group II (+40%) and group III (+41%). Simultaneously, the most pronounced increase in EVLW could be observed in group I (+25%) as well. Pulmonary gas exchange in group I was more compromised (PaO2 -72 mmHg) than in group II (-38 mmHg) and group III (-50 mmHg). No correlation between EVLW and COP-PCP-gradient could be observed. In spite of a significant elevation of COP by using 20% albumin solution, EVLW increased with subsequent deterioration of pulmonary gas exchange. The presented data demonstrate no advantage of albumin 20%; if volume substitution is necessary after ECC, low concentrated plasmaexpanders (up to 10 ml/kg b.w.) may be preferred for several reasons.

During cardiac surgery treatment of deterioration of myocardial function is usually based on catecholamines. Development of selective phosphodiesterase-(PDE-)III-inhibitors seems to be a new aspect in treating myocardial dysfunction. Therefore the hemodynamic effects of the new PDE-inhibitor enoximone were investigated in 20 coronary surgery patients unable to be weaned from extracorporeal circulation (ECC) without pharmacological intervention (MAP less than 60 mmHg, CI less than 2.00 l/min.m2, PCP greater than 15 mmHg). After controlled reperfusion with 2.4 1/min.m2 two groups were separated in a random sequence receiving either 0.5 mg/kg enoximone as a bolus (n = 10), or dobutamine (n = 10, 5 micrograms/kg.min) as perfusion. In the dobutamine-group MAP and CI (-14%) were decreased, while HR was increased significantly (+30%). Application of enoximone was followed by a slight increase in CI (+5%), a significant decrease in TSR while HR remained almost unchanged. PCP, too, differed significantly between the groups (enoximone: -38%; dobutamine: -10%). Ten minutes after weaning from ECC additional pharmacologic therapy (calcium, vasodilators, epinephrine) was necessary in eight dobutamine treated patients in contrast to four patients in the enoximone group (calcium, epinephrine). In patients with impaired myocardial performance during weaning from ECC enoximone seems to be an alternative therapy and is judged to be of some advantage compared to dobutamine application in this situation. The mechanism for improvement appears to be enhanced contractility owing to its positive inotropic effects, as well as a decrease in left ventricular outflow resistance resulting from peripheral vasodilation.

The influence of ventilation with different endexpiratory pressure (0, 5, 10 cm H2O) on extravascular lung water (EVLW) in the period immediately after extracorporeal circulation (ECC) was investigated in a total of 35 patients undergoing coronary artery bypass surgery. Lung water measurement was performed by using the thermal-green dye double indicator dilution technique with indocyanine green and a microprocessed lung water computer. Ventilation with a moderate PEEP-level (5 cm H2O) led to an intensive reduction in lung water content, whereas EVLW-reduction was less pronounced, when higher PEEP-level (10 cm H2O) was applied. No significant relationship to various hemodynamic parameters, especially pulmonary artery pressure (PAP), pulmonary capillary wedge pressure (PCWP) or pulmonary vascular resistance (PVR) could be seen.

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.

Normovolemic hemodilution (15 mg/kg body-weight: group I) was undertaken in 100 patients immediately before the start of coronary-artery surgery. In addition, a Cell-Saver (Haemonetics, Munich) was used for intra-operative autotransfusion. Another group of 100 patients (group II) was similarly operated on without autotransfusion (the study was conducted on 200 consecutive patients undergoing aorto-coronary bypass). Before blood (autologous or homologous) was administered a reduction of hemoglobin to 9 g/100 ml and hematocrit to 0.28 was well tolerated (during extracorporeal circulation: 6.5 g/100 ml and 0.16, respectively). Due to intra- and postoperative complications, such as infarct bleeding (including reoperation) or septicemia, the number of patients placed in group I fell to 94, that in group II to 90. Acute normovolemic hemodilution increased cardiac output and oxygen transport capacity, while other hemodynamic parameters remained unchanged, and there was no effect on extravascular lung water. Autotransfusion reduced the need for homologous blood derivatives by 71% (fresh blood, fresh plasma, RBC concentrates). No clinically significant disadvantages occurred.

The haemodynamic effects of 0.03 mg/kg bwxh (approximately equal to 0.5 microgram/kg bwxmin) and 0.06 mg/kg bwxh (approximately equal to 1.0 microgram/kg bwxmin) nimodipine as an infusion has been studied in 64 patients undergoing aorto-coronary-bypass surgery. The measurements were performed at 4 different times: 1. before induction of anaesthesia, 2. after induction of anaesthesia, 3. before cannulation of the aorta, 4. during extracorporeal circulation (ECC). After ECC haemodynamics were controlled in detail as a follow-up study. Each group was compared to a control group having received 0.9% NaCl as placebo. Preoperative infusion of 0.03 mg/kg bwxh nimodipine caused no relevant influence on haemodynamics, whereas 0.06 mg/kg bwxh led to a decrease in arterial blood pressure, peripheral and pulmonary vascular resistance and to a simultaneous increase in cardiac index. Similar haemodynamic effects were registered intraoperatively with both dosages. There was no relevant influence on contractility. During ECC nimodipine led to a decrease in arterial perfusion pressure and oxygenator volume, thus indicating arterial vasodilation and venous pooling. After ECC the investigation revealed a stabilization in cardiac rhythm and myocardial function. With respect to haemodynamics 0.03 mg/kg bwxh nimodipine, a dosage being used in neurosurgery, can be classified as safe. When higher dosages are necessary continuous haemodynamic and cerebral monitoring are recommended in order to avoid a hazardous drop in arterial blood pressure with a consecutive decrease in myocardial and cerebral blood flow (steal phenomena) in spite of better global perfusion.

The results of experimental studies with etomidate demonstrating positive hemodynamic effects as well as a decrease in intracranial pressure induced a study using etomidate during cardiac surgery. This randomized study including 506 patients should prove the influence of etomidate on the rate of psychic disturbances after cardiac surgery. Patients treated with etomidate received a loading dose of 1 mg/kg b.w. etomidate within 15 minutes followed by a continuous infusion of 1 mg/kg b.w./h until the end of ECC. Patients without etomidate were the control group. Psychic disturbances were observed in 25% of the control group and in 30% of the etomidate group. In both groups of patients there was a fair number of patients with perioperative cardiopulmonary problems (artificial ventilation longer than 24 hours; catecholamine therapy: epinephrine greater than 5 micrograms/min longer than 3 hours): 8% in the control group and 20% in the etomidate group. These results indicate that etomidate does not beneficially influence the rate of psychic disturbances after open-heart surgery; it may induce, however, cardiopulmonary side effects after cardiac surgery. The results of recent studies indicating drug induced adrenal insufficiency are discussed.

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.

The new phosphodiesterase-III inhibitor (PDI) enoximone is a non-catecholamine, non-glycoside cardiotonic agent with concomitant vasodilating properties. It has proved beneficial in patients with severe chronic heart failure. The influence of enoximone i.v. on hemodynamics was investigated during cardiac surgery under various conditions. METHODS. A randomized series of 60 patients undergoing elective aorto-coronary bypass grafting were studied. The hemodynamic effects of 0.5 mg/kg enoximone given i.v. as a bolus (30 s) were investigated before anesthesia (n = 10), during anesthesia (n = 10), and during extracorporeal circulation (ECC, n = 10) and compared with those observed in corresponding control groups (n = 10 in each control) of patients who had received saline solution as placebo. Anesthesia was maintained with weight-dependent dosages of fentanyl, midazolam and pancuronium bromide. All patients were invasively monitored by means of a pulmonary artery catheter. Additionally, left ventricular pressure (LVP), left ventricular end-diastolic pressure (LVEDP) and dp/dtmax were measured before the initiation of ECC. During ECC direct vascular effects were investigated with measurement of perfusion pressure and the volume of the oxygenator. RESULTS. Before the induction of anesthesia no significant change in MAP and HR could be observed, whereas CI increased (+20%) and TSR decreased (-24%) significantly. During anesthesia, the injection of enoximone was followed by a significant decrease in MAP only in the 1st min (-17%); baseline level was reached again after 6 min; and HR was slightly increased (+8%). TSR (-31%) and LVEDP (-38%) decreased, whereas CI (+17%) and dp/dtmax (+45%) were increased significantly. During ECC perfusion pressure (-37%) and the volume of the oxygenator (-17%) were significantly decreased, demonstrating direct vasodilating effects on both the arteries and the vein. CONCLUSION. Arterial and venous vasodilation with an increase in myocardial performance (dp/dtmax) resulting in an increase in CI were the predominant hemodynamic effects of enoximone i.v. No arrhythmogenic effects or interactions with the anesthetics used were observed in this study.

The haemodynamic effects of 0.35 micrograms/kg bw/min and 0.70 micrograms/kg bw/min nifedipine (Adalat) as an infusion have been studied in 64 patients undergoing aortocoronary bypass surgery. The measurements were performed at four different times: 1. before induction of anaesthesia, 2. after induction of anaesthesia, 3. before cannulation of the aorta, 4. during extracorporeal circulation (ECC). In a follow-up study haemodynamics were controlled in detail after weaning from ECC. Each group was compared to a control group having received 0.9% NaCl as placebo. Preoperative as well as intraoperative application of nifedipine led to a decrease in arterial pressure and total systemic resistance, whereas cardiac index showed an increase. Heart rate, central venous pressure, pulmonary artery and pulmonary capillary wedge pressure remained almost unchanged. No relevant effect on contractility could be seen. During ECC nifedipine led to a decrease in arterial perfusion pressure and oxygenator-volume, thus indicating arterial vasodilatation and venous pooling. The investigations after ECC demonstrated stabilisation in cardiac rhythm and myocardial function. In conclusion, dose-dependent haemodynamic changes after intravenous application of nifedipine indicate a reduction in myocardial oxygen demand without detrimental effects on myocardial performance.

From 10 patients with myocardial insufficiency arterial blood samples were taken, in order to study lidocaine plasma concentrations following reduced iv. bolus administration (0.5 mg/kg body weight) and subsequent infusion (2 mg/min). Drug concentrations were monitored by means of gas chromatography. The results obtained from the reduced loading dose of lidocaine were nearly identical to those from patients without myocardial insufficiency and an iv. bolus injection of 1 mg lidocaine/kg body weight. The reduced hepatic metabolism of lidocaine caused by manifest myocardial insufficiency requires a significantly reduced loading dose not exceeding the therapeutic range, even in intraoperative short-term use.

Our investigations have shown the following: 1. 8-Chloro-6-(2-fluorophenyl)-1-methyl-4H-imidazo[1,5-a] [1,4]benzodiazepine (midazolam, Ro 21-3981, Dormicum) produces no adverse haemodynamic changes in healthy subjects. 2. The reduction in peripheral resistance becomes apparent mainly in the case of raised baseline values, as, for example, in hypertensive subjects, but it can also be of significance prior to anaesthesia, when there may be raised systemic vascular resistance due to stress. 3. Venous pooling, which leads to a decrease in pre-load and subsequent lowering of the cardiac index, can have a compensatory effect in cardiac insufficiency. Under certain conditions, as for example, in the case of imminent volume deficit, a marked fall in pressure is to be expected. 4. The haemodynamic effects of midazolam are thus limited to vascular reactions. Under certain circumstances volume therapy may be necessary before the drug is used.

Lormetazepam, a new short-acting benzodiazepine, was studied in 30 patients undergoing coronary artery bypass grafting (10 patients before induction of anaesthesia, 8 patients before extracorporeal circulation, 12 patients during extracorporeal circulation). Before induction of anaesthesia lormetazepam caused only a small reduction in CI, heart rate and a moderate hypoventilation. During anaesthesia (fentanyl, pancuronium bromide, ventilation with N2O/O2 1: 1) there was a decrease in CI (26%), SI (18%), HR (5,7%), dp/dt (15%) and an increase in TSR (25%) and TPR (32%); Part, PAP, PCWP and PRA remained unchanged. There was a small decrease in myocardial oxygen consumption. During ECC lormetazepam increased the arterial perfusion pressure (20%); the priming volume of the oxygenator decreased by 48% at the same time, indicating venous pooling.

Routine administration of homologous fresh frozen plasma (FFP) is widely carried out in cardiac surgery although the risks of blood transfusion can never be excluded. The effect of two units of FFP (430 +/- 11 ml) given after the end of extracorporeal circulation (ECC) (group 1, n = 20) was compared to a control group (n = 20) without FFP in elective aorto coronary bypass patients. Various laboratory parameters, including coagulation data, were measured before and after the end of ECC up to the 1st postoperative day. The patients were comparable with regard to biometric data, anesthesia, and surgical procedure. The major result of this study shows, that routine administration of FFP has no beneficial effect with respect to hemostatic balance. In comparison to a control group, the increase in elastase and decrease in paO2 was even more pronounced in the FFP group. Both blood loss and the need for blood transfusion did not differ between the groups. It can be concluded that a bleeding tendency in cardiac surgery may be caused by ECC itself and by perioperative plasma loss. The routine administration of a relatively small amount of FFP has no positive influence on hemostasis. Substitution therapy in this situation should be guided by the results of coagulation studies.

Measurement of hemodynamic parameters by noninvasive techniques is gaining more and more popularity in the face of severe complications associated with invasive methods. Thoracic electrical bioimpedance is a noninvasive means of estimating cardiac output (CO) and pulmonary edema formation. The validity of this method, however, has been controversial. In the present study a new bioimpedance monitoring system (NCCOM 3) was used in 10 intensive care patients undergoing mechanical hemofiltration (group I) and in 20 cardiac surgery patients undergoing either aortic valve replacement (AVR, group IIa, n = 10) or aorto-coronary bypass grafting (CABG, group IIb, n = 10). In cardiac surgery patients the measurements were performed before as well as after extracorporeal circulation (ECC). CO measured by the impedance monitor was compared to the standard thermodilution method; pulmonary fluids were estimated by a thermo-dye technique and by measurement of total electrical impedance (base impedance), expressed as the thoracic fluid index (TFI). The principal finding of the study was that CO as measured by the two techniques differed significantly in all groups with regard to absolute values. The relative changes in CO, however, were comparable in both intensive care patients and CABG patients. In patients with special thoracic blood flow conditions (regurgitation in aortic insufficiency patients), no corresponding course of CO could be found.(ABSTRACT TRUNCATED AT 250 WORDS)

Diltiazem is a calcium channel blocker whose effects lie between those of the two other important calcium antagonists nifedipine and verapamil. In addition to vasodilation, it has a negative dromotropic effect with prolongation of the A-V interval. In animal experiments and human investigations, diltiazem improves the function of ischemic myocardium due to a direct dilating effect on coronary vessels. The purpose of the present study was to investigate the hemodynamic effects of diltiazem in patients before and during coronary revascularization. METHODS. The study included 60 consenting male patients with coronary heart disease. Twenty premedicated patients randomly received 0.3 mg/kg diltiazem or placebo within 3 min before induction of anesthesia. Hemodynamic measurements (arterial pressure, heart rate, mean pulmonary arterial pressure, pulmonary capillary pressure, right atrial pressure and cardiac output) were taken during the following 21 min. Before cannulation of the great vessels for institution of extracorporeal circulation (ECC), 20 other patients received 0.014 mg diltiazem or placebo/kg per min over 20 min. In addition to the above mentioned hemodynamic measurements, left ventricular parameters (LVP, LVEDP, dp/dt) were directly registered, and 5 min after the end of ECC the measurements were repeated with the same preload as before the ECC. Twenty additional patients received 0.014 mg diltiazem or placebo/kg per min within 21 min during ECC observing arterial perfusion pressure and oxygenator volume. RESULTS. Pre- and intraoperatively diltiazem caused a decrease in mean arterial pressure; cardiac index increased only during the preoperative investigation period (Tables 1, 2), whereas stroke volume index increased pre- and intraoperatively; heart rate decreased in all patients as well as dp/dt (Fig. 1).(ABSTRACT TRUNCATED AT 250 WORDS)

The haemodynamic and respiratory-depressive effects of 20 micrograms/kg and 40 micrograms/kg of alfentanil in 54 patients with coronary bypass operation were compared with a control group (n = 36). The measurements were carried out at 3 different times, each lasting over a 10 min period: 1. Before induction of anaesthesia but after premedication with flunitrazepam. 2. During anaesthesia and 3. during extracorporeal circulation (standardized conditions).--The preoperative as well as the intraoperative investigations showed a reduction in pulse rate, mean arterial pressure, left ventricular pressure and arterial perfusion pressure during extracorporeal circulation. As cardiac output remained constant in the awake patient, peripheral vasodilatation was predominant. Aside from this during anaesthesia reduction in cardiac output may have been responsible for the decrease in pressure although the cause of this could be the nitrous oxide as well. During the preoperative period a clear increase in wedge pressure, mean pulmonary artery pressure, right atrial pressure and pulmonary vascular resistance occurred from the 3rd minute after the injection. The cause is a vasoconstriction during apnoea. In the intraoperative period this did not occur. The respiratory depression(paO2: -34%, paCO2: +29%) resembles that after fentanyl, except that it starts earlier and lasts for a shorter time. In summary, it can be stated that all effects after alfentanil are similar to those of fentanyl.

Twenty-five patients undergoing aortic valve replacement were administered two different electrolyte solutions pre- and intraoperatively: patients in group A (n = 9) received a balanced solution of electrolytes and trace metals with aspartate as anion (Inzolen), patients in group B (n = 16) received Ringer's solution with potassium chloride referenced to frequently-measured serum potassium levels. From the left ventricular apex region, needle biopsies were obtained at three points in time: 1. beginning of CPB, 2. end of ischemia, 3. after ten minutes of reperfusion. The tissue samples were enzymatically analyzed for the content of ATP, CP, ADP and lactate. In group A (patients with aspartate) ATP (moderately) and CP (markedly) decreased after ischemia with a marked increase after reperfusion. ADP and lactate in this group (A) increased at the end of ischemia and decreased after reperfusion. ATP and CP in group B (KCl) showed a similar course during the investigation. Lactate (markedly) and ADP (moderately) increased after ischemia without changing after reperfusion. Mean values of ATP and CP in group A were significantly higher than those of group B at all times. Mean values of ADP and lactate, however, in group A were below those of group B. The data indicate an improvement in energetic metabolism of myocardium in man. The results point out the possible importance of aspartates in compound with electrolytes and trace metals in preservation of biochemical energy.

Cardiovascular arrest may be followed by severe respiratory insufficiency due to an increase in the pressure in the pulmonary vascular system, an alteration in capillary permeability, or both. Extracorporeal circulation (ECC), on the other hand, can lead to a change in capillary integrity ('capillary leakage') caused by the unphysiologic perfusion patterns and/or activation of various mediator systems. Pulmonary hyperhydration (increased extravascular lung water [EVLW]) seems to be the most important factor limiting pulmonary function in this situation. This retrospective study was designed to investigate the influence of resuscitation in the period before ECC on pulmonary EVLW thereafter. Eight coronary surgery patients who had to be resuscitated in the period before the start of ECC due to cardiocirculatory arrest were compared to 8 patients without resuscitation selected randomly (control group). There were no differences between the two groups with regard to age, catheterization data, and ECC conditions. All patients underwent identical monitoring, including estimation of EVLW. Lung water measurement was performed by the thermal dye technique with indocyanine green (= non-diffusible indicator) dissolved in ice-cold dextrose (= diffusible indicator) and a bedside microprocessor before resusciation and after ECC (15 min, 45 min, 5h). Simultaneously, hemodynamics and parameters of pulmonary gas exchange were monitored. Baseline values of EVLW were comparable in both groups. After ECC a transient increase in EVLW could be demonstrated in the controls, indicating an altered fluid flux even in 'uncomplicated' courses; 5 h after ECC lung water content had again reached baseline values. In contrast, there was a significant increase in EVLW in the 'complicated group' immediately after ECC (+2.60 ml/kg) and 5 h after ECC (+1.38 ml/kg); in consequence, the paO2 was significantly decreased (-180 mmHg) while Qs/Qt was increased (+6.79%). It is concluded that the combination of two factors that potentially damage pulmonary tissue and increase lung water content (reanimation due to circulatory arrest and extracorporeal circulation) lead to a significant increase in extravascular lung water combined with a deterioration of pulmonary function, resulting in severe respiratory failure.

Spectral analysis with the compressed spectral array display (CSA) and calculation of spectral edge frequency (SEF) was performed in 43 cases undergoing endarterectomy of the carotid bifurcation. New neurologic deficit appeared in 2 patients (= 4.6%). One of them died postoperatively (= 2.3%), the other suffered from permanent paralysis of the hand. Another 9 patients showed loss of high frequency activity (= decrease in SEF) without a new deficit in the postoperative period. A significant EEG event was defined as a decrease in SEF after carotid cross clamping for at least 5 min. Fisher's exact probability test revealed a close correlation between these EEG events and neurologic outcome. The sensitivity of the test, which was calculated on true positive and false negative events, was 100%, the specificity, based on true negative and false positive events, was 76%. The predictability of the test, based on all EEG events, was 18%; respectively 40% when calculated on significant events.

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.