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Discusses the abstract of the article "Cardioprotective Effects of Volatile Anaesthetics," by S. Cromheecke and colleagues submitted at the 27th Congress of The Scandinavian Society of Anesthesiology and Intensive Care Medicine.

Background: Although moderate hemodilution is usually well tolerated in coronary artery surgery patients, this may not be the case when myocardial oxygen demand is increased. We hypothesized that, in these patients, hemodilution in the presence of an increased heart rate could be associated with an impairment of myocardial function., Methods: Forty coronary surgery patients were randomly assigned to two groups (n=20), according to the rate of atrioventricular pacing [70 bpm (Group 70) or 90 bpm (Group 90)]. While paced at the fixed heart rate, hemodilution was performed before the start of cardiopulmonary bypass. Data were obtained from a pulmonary artery, a PiCCO catheter and a left ventricular pressure catheter. Measurements were obtained in steady-state conditions before and after isovolemic hemodilution., Results: Hemodilution from 40%+/-2% to 30%+/-1% in Group 70, and from 39%+/-4% to 30%+/-2% in Group 90 resulted in a decrease in systemic vascular resistance and an increase in end-diastolic volume in both groups. This was associated with an increase in stroke volume in Group 70 but not in Group 90. In this latter group, the maximal rate of pressure development decreased significantly after hemodilution [from 856+/-93 to 716+/-80 mm Hg/s (P<0.01)], whereas it remained unchanged in Group 70 (843+/-86 mm Hg/s before and 832+/-79 mm Hg/s after hemodilution)., Conclusions: In the conditions of the present study, increased heart rate during moderate hemodilution was associated with a depression of myocardial function.

Objective: To evaluate the effects of 2 different administration modalities of levosimendan (start before cardiopulmonary bypass [CPB] and at the end of CPB) compared with a standard treatment with milrinone started at the end of CPB in cardiac surgery patients with a preoperative ejection fraction <30%., Design: A prospective study., Setting: A university hospital., Participants: Sixty patients undergoing elective cardiac surgery with CPB., Interventions: Patients were randomly assigned to 3 different treatment options for weaning from CPB after cardiac surgery. Group A received milrinone, 0.5 microg/kg/min, after the release of the aortic cross-clamp; group B received levosimendan, 0.1 microg/kg/min, after the induction of anesthesia; and in group C, levosimendan, 0.1 microg/kg/min, was started immediately after the release of the aortic cross-clamp. In all patients, additional dobutamine, 5 microg/kg/min, was initiated after the release of the aortic cross-clamp. Norepinephrine maintained mean arterial pressure constant., Measurements and Main Results: Stroke volume after surgery was initially higher than at baseline in all groups and highest in group B. Stroke volume declined 12 hours after surgery in group A but not in groups B and C (p < 0.05 between groups), despite similar filling pressures. Four patients in group A, none in group B, and 1 in group C died within 30 days of surgery. Postoperative atrial fibrillation was observed in 10 patients in group A, 7 patients in group C, and only 1 in group B (p < 0.01). No differences were observed in postoperative troponin I release among groups., Conclusion: In the conditions of the present study, starting the levosimendan treatment before CPB was associated with a higher initial postoperative stroke volume and a lower incidence of postoperative atrial fibrillation, but had no effect on the extent of postoperative troponin I release.

Myocardial ischemia during the perioperative period is a major cause of morbidity and mortality after surgery. Experimental data indicate that clinical concentrations of volatile anesthetics protect the myocardium from ischemia and reperfusion injury, as shown by decreased infarct size and more rapid postoperative recovery of contractile function. These anesthetics may also mediate protective effects in other organs, such as the brain and kidney. A number of recent reports have indicated that these experimentally observed protective effects might also be present in the clinical setting. Implementation of such cardioprotection during surgery may provide an additional tool in the treatment and prevention of ischemic cardiac dysfunction in the perioperative period. This review discusses the clinical studies that have focused on the potential cardioprotective effects of volatile anesthetic agents.

Objective: To compare an arterial pressure-derived cardiac output (APCO) (Vigileo software version 1.07; Edwards Lifesciences, Irvine, CA) and a thermodilution cardiac output (CCO) as methods for measuring cardiac output under different pathologic and experimental conditions that induce changes in arterial waveform morphology., Design: A prospective study., Setting: A university hospital, single institutional., Participants: Fifty-two patients undergoing elective cardiac surgery., Interventions: Simultaneous APCO and CCO were compared in low-risk patients undergoing elective coronary artery surgery (without valvular disease) (control, n = 20), patients with aortic stenosis (AS, n = 10), aortic insufficiency (AI, n = 10), and intra-aortic balloon pump (IABP, n = 12). In the control group, additional data were registered before and after median sternotomy and phenylephrine administration., Measurements and Main Results: In the control group, Bland-Altman showed a bias of -3% (95% limits of agreement: -59% to +53%) before cardiopulmonary bypass (CPB) and of -1% (95% limits of agreement: -51% to +50%) after CPB. In the AS group, the bias was -5% (95% limits of agreement: -34% to +24%) before CPB and 1% (95% limits of agreement: -28 to +30%) after CPB. In the AI group bias was +32% (95% limits of agreement: -4% to +68%) before CPB and -2% (95% limits of agreement: -35% to +32%) after CPB. Median sternotomy decreased CCO by 10% +/- 10%, whereas it increased APCO by 56% +/- 28%. Phenylephrine administration decreased CCO by 11% +/- 16%, whereas it increased APCO by 55% +/- 34%., Conclusions: Cardiac output measurement based on uncalibrated pulse contour analysis is able to reflect cardiac output measured with the continuous thermodilution method in patients undergoing uncomplicated coronary artery surgery. However, in situations in which the arterial pressure waveform is changed, agreement between techniques may be altered and data obtained with uncalibrated pulse contour analysis may become less reliable.

Objective: The purpose of this study was to determine whether a relationship exists between the inferior vena cava diameter (IVCD) or the superior vena cava diameter (SVCD) measured at the point of entry into the right atrium using transesophageal echocardiography (TEE) and the central venous pressure (CVP) under different experimental conditions., Design: Prospective study., Setting: University hospital, single institution., Participants: Seventy patients undergoing elective cardiac surgery., Interventions: CVP, IVCD, and SVCD were measured in a 2-dimensional, long-axis midesophageal bicaval view at end-diastole with electrocardiographic synchronization. Data were recorded during suspended ventilation, before and after leg elevation, and at different levels of positive end-expiratory pressure (0, 5, and 10 cmH(2)O)., Measurements and Main Results: The relationship between IVCD and CVP had 2 portions: A first (CVP 11 mmHg) in which the correlation was poor (R = 0.272, p = 0.065). No correlation between SVCD and CVP was observed., Conclusion: A strong correlation between TEE-derived IVCD measured at the point of entry into the right atrium and CVP was observed in cardiac surgical patients when CVP was

Background: Patients with poor left ventricular function often require inotropic drug support immediately after cardiopulmonary bypass. Levosimendan improves cardiac function by a novel mechanism of action compared to currently available drugs. We hypothesized that, in patients with severely compromised ventricular function, the use of levosimendan would be associated with better postoperative cardiac function than with inotropic drugs that increase myocardial oxygen consumption., Methods: Thirty patients with a preoperative ejection fraction < or =30% scheduled for elective cardiac surgery with cardiopulmonary bypass were randomized to two different inotropic protocols: milrinone 0.5 microg [corrected] x kg(-1) x min(-1) or levosimendan 0.1 microg [corrected] x kg(-1) x min(-1), started immediately after the release of the aortic crossclamp. The treatment was masked to the observers. All patients received dobutamine 5 microg [corrected] x kg(-1) x min(-1)., Results: Stroke volume was similar between groups initially after surgery, but it declined 12 h after surgery in the milrinone group but not in the levosimendan group (P < 0.05 between groups) despite similar filling pressures. Total dose, duration of inotropic drug administration and norepinephrine dose were lower in the levosimendan group than in the milrinone group (P < 0.05). The duration of tracheal intubation was shorter in the former group compared with the milrinone group (P = 0008). Three patients in the milrinone group but none in the levosimendan group died within 30 days of surgery., Conclusion: In cardiac surgery patients with a low preoperative ejection fraction, stroke volume was better maintained with the combination of dobutamine with levosimendan than with the combination of dobutamine with milrinone.

Objective: The purpose of this study was to compare the effects of a total intravenous and a volatile anesthetic regimen on biochemical markers of hepatic and renal dysfunction after coronary artery surgery., Design: Prospective, double-blind, randomized clinical study., Setting: University hospital, single institutional., Participants: Three hundred twenty patients undergoing elective coronary artery surgery were divided into 2 different anesthetic protocols: propofol group (n = 160) and sevoflurane group (n = 160)., Interventions: Hemodynamic data were registered before the start of surgery, before the start of CPB, 15 minutes after the end of CPB, at arrival in the intensive care unit, and 6 and 12 hours after arrival in the intensive care unit. Serum glutamic oxaloacetic transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT), serum lactate dehydrogenase (LDH), and serum creatinine concentrations were measured before surgery, at arrival in the intensive care unit, and after 6, 12, 24, and 48 hours., Measurements and Main Results: Postoperative levels of serum SGOT, SGPT, and LDH increased transiently in both anesthetic groups, but the increase was significantly lower in the sevoflurane group compared with the propofol group. Creatinine levels remained largely unchanged in both groups., Conclusion: Postoperative biochemical markers of hepatic dysfunction were lower with a sevoflurane-based anesthetic regimen in patients undergoing coronary artery surgery with cardiopulmonary bypass.

In coronary surgery patients the use of a volatile anesthetic regimen with sevoflurane was associated with a better recovery of myocardial function and less postoperative release of troponin I. In the present study we investigated whether these cardioprotective properties were also apparent in the cardiac surgical setting of aortic valve replacement (AVR) surgery for the correction of aortic stenosis. Thirty AVR surgery patients were randomly assigned to receive either target-controlled infusion of propofol or inhaled anesthesia with sevoflurane. Cardiac function was assessed perioperatively using a pulmonary artery catheter. Perioperatively, a high-fidelity pressure catheter was positioned in the left ventricle. Postoperative concentrations of cardiac troponin I were followed for 48 h. After cardiopulmonary bypass (CPB), stroke volume and dP/dt(max) were significantly higher in the patients with sevoflurane. Post-CPB, the effects of an increase in cardiac load on dP/dt(max) were similar to pre-CPB in the sevoflurane group (1.0 % +/- 5.4% post-CPB versus 1.3% +/- 8.6% pre-CPB) but more depressed in the propofol group (-8.2% +/- 4.4% post-CPB versus 0.1% +/- 4.9% pre-CPB). The rate of relaxation was significantly slower post-CPB in the propofol group. Postoperative levels of troponin I were significantly lower in the sevoflurane group. Our data indicate that the use of a volatile anesthetic regimen in AVR surgery was associated with better preservation of myocardial function and a reduced postoperative release of troponin I.

Objective: The purpose of this study was to compare dP/dt(max) estimated from a femoral artery pressure tracing to left ventricular (LV) dP/dt(max) during various alterations in myocardial loading and contractile function., Participants: Seventy patients scheduled for elective coronary artery bypass surgery., Methods: All patients were instrumented with a high-fidelity LV catheter, a pulmonary artery catheter, and a femoral arterial catheter. In 40 patients, hemodynamic measurements were performed before and after passive leg raising and before and after calcium administration (5 mg/kg); and in 30 other patients, hemodynamic measurements were performed before and after dobutamine infusion (5 microg/kg/min over 10 minutes)., Results: LV and femoral dP/dt(max) were significantly correlated (r = 0.82, p < 0.001), but femoral dP/dt(max) systematically underestimated LV dP/dt(max) (bias = -361 +/- 96 mmHg/s). Passive leg raising induced significant increases in central venous pressure and LV end-diastolic pressure, but femoral dP/dt(max), stroke volume, and LV dP/dt(max) remained unaltered. Calcium administration induced significant and marked increases in LV dP/dt(max) (23% +/- 9%) and femoral dP/dt(max) (37% +/- 14%) associated with a significant increase in stroke volume (9% +/- 2%). Dobutamine infusion also induced significant and marked increases in LV dP/dt(max) (25% +/- 8%) and femoral dP/dt(max) (35% +/- 12%) associated with a significant increase in stroke volume (14% +/- 3%). Overall, a very close linear relationship (r = 0.93) and a good agreement (bias = -5 +/- 17 mmHg/s) were found between changes in LV dP/dt(max) and changes in femoral dP/dt(max). A very close relationship was also observed between changes in LV dP/dt(max) and changes in femoral dP/dt(max) during each intervention (leg raising, calcium administration, and dobutamine infusion)., Conclusion: Femoral dP/dt(max) underestimated LV dP/dt(max), but changes in femoral dP/dt(max) accurately reflected changes in LV dP/dt(max) during various interventions.

In this prospective, randomized, open controlled study we compared the effects on net red blood cell loss of 6% hydroxyethyl starch 130/0.4 (HES: n = 64) and 3% modified fluid gelatin (GEL: n = 68) administered for intravascular volume management in patients undergoing coronary surgery. Blood losses were calculated from determination of circulating blood volume and measurement of preoperative and postoperative hematocrit. Amount of colloids that could be administered was limited to 50 mL/kg. If additional fluids were required, balanced crystalloid solution was used. Anesthetic and surgical techniques were standardized. Both groups were similar with regard to demographic and intraoperative variables. Total study drug was 48.9 +/- 17.2 mL/kg in the HES group and 48.9 +/- 14.6 mL/kg in the GEL group. Total red blood cell loss was 544 +/- 305 mL in the HES group and 504 +/- 327 mL the GEL group. Measured blood losses were also similar in both groups (HES, 19.4 +/- 12.3 mL/kg; GEL, 19.2 +/- 14.5 mL/kg). Exposure to allogeneic blood product was comparable in both groups. In the conditions of the present study, HES 130/0.4 up to 50 mL/kg is a valuable alternative to modified fluid gelatin for plasma volume expansion during and after cardiac surgery.

Occurrence of atrial fibrillation is a common complication after coronary surgery. This study aimed to identify the perioperative factors that are associated with its occurrence with specific attention to the possible influence of the choice of the anesthetic regimen after elective coronary surgery. A retrospective chart analysis was performed in 460 patients who underwent elective coronary artery surgery with cardiopulmonary bypass using the standard institutional anesthetic, surgical and postoperative protocols. The only difference in management was the choice of the primary anesthetic regimen. 110 patients had a total intravenous anesthesia with propofol, 90 patients had a total intravenous anesthesia with midazolam, 150 patients were anesthetized with sevoflurane and 110 patients with desflurane. The primary outcome variable was the incidence of atrial fibrillation within the first 24 postoperative hours. Atrial fibrillation occurred in 64 of the 460 patients included (13.9%). Multiple logistic regression analysis identified increased age (> 70 years), EuroSCORE > 4, prolonged CPB time (> 100 min) and need for prolonged inotropic support (> 6 hours) as the significant independent risk factors for the occurrence of postoperative atrial fibrillation. The incidence of postoperative atrial fibrillation differed among the different anesthetic groups with the lowest incidence in the sevoflurane group (propofol: 17/110; midazolam: 15/90; sevoflurane: 9/150; desflurane: 23/110) (p = 0.004). This finding should be further confirmed in a prospective sufficiently powered multicenter study.