Stefanie Cromheecke

Cardioprotective properties of sevoflurane in patients undergoing coronary surgery with cardiopulmonary bypass are related to the modalities of its administration

Background:Experimental studies have related the cardioprotective effects of sevoflurane both to preconditioning properties and to beneficial effects during reperfusion. In clinical studies, the cardioprotective effects of volatile agents seem more important when administered throughout the procedure than when used only in the preconditioning period. The authors hypothesized that the cardioprotective effects of sevoflurane observed in patients undergoing coronary surgery with cardiopulmonary bypass are related to timing and duration of its administration. Methods:Elective coronary surgery patients were randomly assigned to four different anesthetic protocols (n = 50 each). In a first group, patients received a propofol based intravenous regimen (propofol group). In a second group, propofol was replaced by sevoflurane from sternotomy until the start of cardiopulmonary bypass (SEVO pre group). In a third group, propofol was replaced by sevoflurane after completion of the coronary anastomoses (SEVO post group). In a fourth group, propofol was administered until sternotomy and then replaced by sevoflurane for the remaining of the operation (SEVO all group). Postoperative concentrations of cardiac troponin I were followed during 48 h. Cardiac function was assessed perioperatively and during 24 h postoperatively. Results:Postoperative troponin I concentrations in the SEVO all group were lower than in the propofol group. Stroke volume decreased transiently after cardiopulmonary bypass in the propofol group but remained unchanged throughout in the SEVO all group. In the SEVO pre and SEVO post groups, stroke volume also decreased after cardiopulmonary bypass but returned earlier to baseline values than in the propofol group. Duration of stay in the intensive care unit was lower in the SEVO all group than in the propofol group. Conclusion:In patients undergoing coronary artery surgery with cardiopulmonary bypass, the cardioprotective effects of sevoflurane were clinically most apparent when it was administered throughout the operation.

Effects of Propofol, Desflurane, and Sevoflurane on Recovery of Myocardial Function after Coronary Surgery in Elderly High-risk Patients

Background The present study investigated the effects of propofol, desflurane, and sevoflurane on recovery of myocardial function in high-risk coronary surgery patients. High-risk patients were defined as those older than 70 yr with three-vessel disease and an ejection fraction less than 50% with impaired length-dependent regulation of myocardial function. Methods Coronary surgery patients (n = 45) were randomly assigned to receive either target-controlled infusion of propofol or inhalational anesthesia with desflurane or sevoflurane. Cardiac function was assessed perioperatively and during 24 h postoperatively using a Swan-Ganz catheter. Perioperatively, a high-fidelity pressure catheter was positioned in the left and right atrium and ventricle. Response to increased cardiac load, obtained by leg elevation, was assessed before and after cardiopulmonary bypass (CPB). Effects on contraction were evaluated by analysis of changes in dP/dtmax. Effects on relaxation were assessed by analysis of the load-dependence of myocardial relaxation. Postoperative levels of cardiac troponin I were followed for 36 h. Results After CPB, cardiac index and dP/dtmax were significantly lower in patients under propofol anesthesia. Post-CPB, leg elevation resulted in a significantly greater decrease in dP/dtmax in the propofol group, whereas the responses in the desflurane and sevoflurane groups were comparable with the responses before CPB. After CPB, load dependence of left ventricular pressure drop was significantly higher in the propofol group than in the desflurane and sevoflurane group. Troponin I levels were significantly higher in the propofol group. Conclusions Sevoflurane and desflurane but not propofol preserved left ventricular function after CPB in high-risk coronary surgery patients with less evidence of myocardial damage postoperatively.

Choice of Primary Anesthetic Regimen Can Influence Intensive Care Unit Length of Stay after Coronary Surgery with Cardiopulmonary Bypass

Background:Volatile anesthetics protect the myocardium during coronary surgery. This study hypothesized that the use of a volatile agent in the anesthetic regimen would be associated with a shorter intensive care unit (ICU) and hospital length of stay (LOS), compared with a total intravenous anesthetic regimen. Methods:Elective coronary surgery patients were randomly assigned to receive propofol (n = 80), midazolam (n = 80), sevoflurane (n = 80), or desflurane (n = 80) as part of a remifentanil-based anesthetic regimen. Multiple logistic regression analysis was used to identify the independent variables associated with a prolonged ICU LOS. Results:Patient characteristics were similar in all groups. ICU and hospital LOS were lower in the sevoflurane and desflurane groups (P < 0.01). The number of patients who needed a prolonged ICU stay (> 48 h) was also significantly lower (propofol: n = 31; midazolam: n = 34; sevoflurane: n = 10; desflurane: n = 15; P < 0.01). Occurrence of atrial fibrillation, a postoperative troponin I concentration greater than 4 ng/ml, and the need for prolonged inotropic support (> 12 h) were identified as the significant risk factors for prolonged ICU LOS. Postoperative troponin I concentrations and need for prolonged inotropic support were lower in the sevoflurane and desflurane group (P < 0.01). Postoperative cardiac function was also better preserved with the volatile anesthetics. The incidence of other postoperative complications was similar in all groups. Conclusions:The use of sevoflurane and desflurane resulted in a shorter ICU and hospital LOS. This seemed to be related to a better preservation of early postoperative myocardial function.

The effects of levosimendan in cardiac surgery patients with poor left ventricular function.

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 ≤30% scheduled for elective cardiac surgery with cardiopulmonary bypass were randomized to two different inotropic protocols: milrinone 0.5 mg · kg−1 · min−1 or levosimendan 0.1 mg · kg−1 · min−1, started immediately after the release of the aortic crossclamp. The treatment was masked to the observers. All patients received dobutamine 5 mg · kg−1 · 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.

Hydroxyethyl starch 130/0.4 versus modified fluid gelatin for volume expansion in cardiac surgery patients: The effects on perioperative bleeding and transfusion needs

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.

Cardioprotective properties of sevoflurane in patients undergoing aortic valve replacement 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/dtmax were significantly higher in the patients with sevoflurane. Post-CPB, the effects of an increase in cardiac load on dP/dtmax 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.

A randomized trial evaluating different modalities of levosimendan administration in cardiac surgery patients with myocardial dysfunction.

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.

Continuous cardiac output measurement: arterial pressure analysis versus thermodilution technique during cardiac surgery with cardiopulmonary bypass

This study compared cardiac output measured with an arterial pressure‐based cardiac output measurement system and a thermodilution cardiac output measurement system. We studied 36 patients undergoing cardiac surgery with cardiopulmonary bypass. Simultaneous arterial pressure‐based and thermodilution cardiac output measurements were compared before and after cardiopulmonary bypass, and after phenylephrine administration. Bland‐Altman analysis showed good overall agreement between the two methods. Bias (limits of agreement) before and after cardiopulmonary bypass were − 0.21 (− 2.97–2.55) l.min−1 and 0.01 (− 3.79–3.81) l.min−1, respectively. Phenylephrine administration decreased thermodilution cardiac output by a mean (SD) of 11 (16)% and increased arterial pressure‐based cardiac output by 55 (34)%. We conclude that arterial pressure‐based cardiac output and thermodilution cardiac output measurement systems yield comparable results during cardiac surgery with cardiopulmonary bypass. However, after phenylephrine administration, the two measurement systems provided opposing results.

Cardioprotection with Volatile Anesthetics in Cardiac Surgery

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.

Moderate acute isovolemic hemodilution alters myocardial function in patients with coronary artery disease

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.