Suraphong Lorsomradee

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.

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.

The use of a volatile anesthetic regimen protects against acute normovolemic hemodilution induced myocardial depression in patients with coronary artery disease

Background: Previous studies indicated that acute normovolemic hemodilution (ANH) was associated with a depression of myocardial function in coronary surgery patients with baseline heart rate faster than 90 bpm. It was suggested that this phenomenon could be explained by the occurrence of myocardial ischemia. In the present study, we hypothesized that the cardioprotective properties of a volatile anesthetic regimen might protect against the ANH related myocardial functional impairment. Materials and Methods: Forty elective coronary surgery patients with baseline heart rate faster than 90 bpm were randomly allocated to receive different anesthetic regimens. Group A (n = 20) received midazolam-based anesthesia. Group B (n = 20) received a sevoflurane-based anesthesia. Five-lead electrocardiogram, pulse oximetry, capnography, radial arterial pressure, and Swan Ganz continuous thermodilution cardiac output via right internal jugular vein were monitored. Measurements were obtained before and after ANH. Data were compared using paired t test. All data were expressed as mean ± SD. Data were considered significant if P < 0.05. Results: After ANH, systemic vascular resistance was slightly decreased in group A while there was a significant decrease in group B. In group A, cardiac output was slightly decreased from 5.07±1.17 l/min to 5.02±1.28 l/min after ANH, whereas in group B, cardiac output was significantly increased from 4.84±1.21 l/min to 6.02±1.28 l/min after ANH. Conclusion: In coronary surgery patients, with baseline heart rate faster than 90 bpm, anesthesia with sevoflurane during ANH was associated with an improvement in myocardial function after ANH, which was not present in patients anesthetized with midazolam.

Effects of levosimendan in cardiac surgery patients with poor left ventricular function: 4AP7-2

by SDF imaging via an ileostomy in 5 anesthetized pigs. Four sequences of microcirculatory status were recorded on-line at baseline conditions and after first, second and third hour of HHD with Hartmann’s solution (20 mL/kg/h) iv and analyzed off-line. Systolic (SBP), diastolic (DBP) and mean arterial pressures were monitored continuously. One-way ANOVA on ranks was applied to compare changes in FCD during HHD. Results: Data are presented in the table: