The prophylactic use of fibrinogen concentrate in high-risk cardiac surgery.

BACKGROUND: Perioperative blood loss is a major contributor to morbidity and mortality in cardiac surgery. Plasma fibrinogen levels play an essential role in hemostasis and deplete quickly during hemorrhage. The objective of this study was to determine whether prophylactic fibrinogen concentrate administration lowers overall blood product transfusion requirements in high-risk cardiac surgery in patients with low fibrinogen plasma levels. METHODS: The study was performed in a prospective, randomized, and double-blinded design. The investigation included 62 patients undergoing elective, high-risk cardiac surgery. After weaning from cardiopulmonary bypass and reversal of heparin patients received either fibrinogen concentrate or placebo. The primary outcome variable was overall blood product usage 24 hours after intervention. RESULTS: The fibrinogen group received numerically fewer total units of blood products than the placebo group, but the difference was not statistically or clinically significant (for groups n = 27; n = 29 and 19 vs 37 units, respectively, P = .908). The overall transfusion rate in both groups was significantly lower than the institutional average suggested (fibrinogen group 26%, placebo group 28%). The fibrinogen group showed significantly higher fibrinogen levels (2.38 vs 1.83 g/L (end of surgery), P < .001; 3.33 vs 2.68 g/L (12 hours after intervention), P = .003) and improved viscoelastic coagulation parameters (FIBTEM MCF, 27 vs 23 mm, P = .022). CONCLUSION: This randomized, controlled trial demonstrates that point-of-care guided and prophylactic treatment with fibrinogen concentrate does not reduce transfusion of blood products in a setting of unexpectedly low transfusion rate as tested in this cohort, but may improve coagulation parameters in the setting of high-risk cardiac surgery.

Hemodynamic effects of dobutamine and dopexamine after cardiopulmonary bypass in pediatric cardiac surgery.

BACKGROUND: After surgical repair of congenital heart disease, inotropic support is sometimes necessary to wean from cardiopulmonary bypass. In pediatric cardiac surgery, dobutamine and dopamine are often used as inotropic support. Dopexamine is a synthetic catecholamine, which has positive inotropic and vasodilating properties. Because the hemodynamic effects of catecholamines are modified after cardiopulmonary bypass, the aim of this study was to investigate the effects of dobutamine and dopexamine on cardiac index and systemic vascular resistance index after cardiopulmonary bypass in pediatric cardiac surgery. METHODS: The study was performed in a prospective, randomized, and double-blinded cross-over design. The investigation included 11 children for elective, noncomplex congenital heart surgery. After weaning from cardiopulmonary bypass and a 20-min period of steady state, children received either 2.5 microg x kg(-1) x min(-1) dobutamine or 1 microg x kg(-1) x min(-1) dopexamine for 20 min. Cardiac index (transpulmonary thermodilution), mean arterial pressure, central venous pressure, stroke volume, systemic vascular resistance, and central venous oxygen saturation were determined. The primary outcome variable was cardiac index. RESULTS: No difference in cardiac index was observed between the two groups (P = 0.594). Both drugs increased cardiac index, dopexamine from 3.9 +/- 0.6 to 4.7 +/- 0.8 l x min(-1) x m(-2) (P = 0.003) and dobutamine from 4.1 +/- 0.7 to 4.8 +/- 0.7 l x min(-1) x m(-2) (P = 0.004). During treatment with dobutamine, children presented with significantly higher mean arterial pressure (P = 0.003) and systemic vascular resistance index (P = 0.026). CONCLUSIONS: This trial demonstrates that low-dose dobutamine and dopexamine both increase cardiac index during pediatric cardiac surgery but with different hemodynamic effects.

Effect of isoflurane on echocardiographic left-ventricular relaxation indices in patients with diastolic dysfunction due to concentric hypertrophy and ischemic heart disease.

OBJECTIVE: The purpose of this study was to investigate whether isoflurane, a known negative lusitropic agent, exacerbates diastolic dysfunction in patients with preexisting impaired relaxation. DESIGN: Prospective, experimental study. SETTING: Single-institution, university hospital. PARTICIPANTS: Twenty-five patients with diastolic dysfunction due to concentric hypertrophy and ischemic heart disease undergoing elective coronary artery bypass graft surgery. INTERVENTIONS: After approval of the local ethics committee and informed consent, patients randomly received sufentanil/midazolam anesthesia plus either 0.5 to 1.0 minimum alveolar concentration of isoflurane (n = 15) or weight-adjusted boli of urapidil (n = 10) during preparation of the internal mammary artery. Changes in hemodynamic parameters and echocardiographic diastolic indices before and after drug administration were compared. Filling pressures during the study were kept constant within normal range. MEASUREMENTS AND MAIN RESULTS: Hemodynamic changes measured by invasive arterial and pulmonary arterial pressures were comparable between isoflurane and urapidil. Both interventions led to a marked reduction in afterload that was accompanied by a significant increase in thermodilution cardiac output and stroke volume. Transesophageal echocardiographic relaxation indices were also comparable between groups. Transmitral and tissue Doppler E waves increased significantly, leading to larger E/A and Em/Am ratios; whereas the deceleration time and the isovolumetric relaxation time decreased significantly. CONCLUSION: Isoflurane did not exacerbate diastolic dysfunction in patients with concentric hypertrophy and ischemic heart disease. In contrast, isoflurane led to a "normalization" of the relaxation pattern that was attributed to a reduction in left-ventricular loading conditions.

Transesophageal echocardiography as a guide for patient positioning before neurosurgical procedures in semi-sitting position.

With an incidence of a patent foramen ovale in nearly one fourth of the normal population, neurosurgical procedures in the semi-sitting position are associated with the risk of paradoxical air embolism. The present study was undertaken to evaluate an anesthetic concept to detect a patent foramen ovale with the help of transesophageal echocardiography in anesthetized patients before neurosurgical procedures in the semi-sitting position. Transesophageal echocardiography was performed after induction of anesthesia before surgery to avoid additional physical and psychologic stress for the patients. Thirty-five neurosurgical patients scheduled for elective surgery in the semi-sitting position were examined with help of contrast transesophageal echocardiography. The data of the examined patients were analyzed with respect to efficiency, logistic efforts, and adverse events. Contrast transesophageal echocardiography was combined with a ventilation maneuver to increase right atrial pressure. A patent foramen ovale was detected in 3 of 35 patients. These patients were operated on in a supine position. Oral insertion of the echoprobe was possible in all patients without difficulties. A short-lasting hypertension was observed in 5 patients despite adequate analgesia and sedation. The average time of examination was 25 minutes. None of the patients showed paradoxical air embolism as judged by postoperative neurologic assessment. Contrast transesophageal echocardiography combined with a ventilation maneuver is an effective method in detecting a patent foramen ovale. Moreover, transesophageal echocardiography is a clinical guide to patient positioning. The method of anesthetic management presented to examine anesthetized patients immediately before surgery means less physical and psychologic stress for the patients and causes approximately a 30-minute delay of surgery.

The effect of intravenous quinaprilat on plasma cytokines and hemodynamic variables during cardiac surgery.

OBJECTIVES: Perioperative treatment with angiotensin-converting enzyme (ACE) inhibitors in cardiac surgery with cardiopulmonary bypass is still controversial. Using ACE inhibitors during cardiac surgery might be associated with an increased risk of critical hypotensive episodes. On the other hand, ACE inhibitors could have beneficial effects with respect to the development of the systemic inflammatory response syndrome. DESIGN: The effect of acute administration of quinaprilat on hemodynamic variables and plasma cytokines was assessed under double-blind, randomized, and placebo-controlled conditions. SETTING: Department of anesthesiology and cardiovascular surgery clinic in a university hospital. PARTICIPANTS: Forty patients without preexisting cardiac failure, undergoing coronary artery bypass grafting. INTERVENTIONS: Patients received 0.08 mg/kg of intravenous quinaprilat or intravenous isotonic saline solution after induction of anesthesia. MEASUREMENTS AND RESULTS: Blood samples were taken after induction of anesthesia (T0), before cardiopulmonary bypass (T1), at the end of surgery (T2), and 4 hours after the end of surgery (T3). There was no difference between the 2 groups regarding mean arterial pressure and inotropic or vasopressor support. Systemic vascular resistance index was significantly lower in the quinaprilat group at T2 (p = 0.016) and T3 (p = 0.017). No difference in proinflammatory cytokine levels was observed between the 2 groups. CONCLUSIONS: The present investigation shows that acute administration of an intravenous ACE inhibitor, quinaprilat, has no influence on proinflammatory cytokines during cardiac surgery with cardiopulmonary bypass. The patients treated with quinaprilat showed an improved systemic vascular resistance index with no increased risk of deleterious hemodynamic episodes.