Comparison of the effects of albumin 5%, hydroxyethyl starch 130/0.4 6%, and Ringer's lactate on blood loss and coagulation after cardiac surgery.

BACKGROUND: Infusion of 5% human albumin (HA) and 6% hydroxyethyl starch 130/0.4 (HES) during cardiac surgery expand circulating volume to a greater extent than crystalloids and would be suitable for a restrictive fluid therapy regimen. However, HA and HES may affect blood coagulation and could contribute to increased transfusion requirements. METHODS: We randomly assigned 240 patients undergoing elective cardiac surgery to receive up to 50 ml kg(-1) day(-1) of either HA, HES, or Ringer's lactate (RL) as the main infusion fluid perioperatively. Study solutions were supplied in identical bottles dressed in opaque covers. The primary outcome was chest tube drainage over 24 h. Blood transfusions, thromboelastometry variables, perioperative fluid balance, renal function, mortality, intensive care unit, and hospital stay were also assessed. RESULTS: The median cumulative blood loss was not different between the groups (HA: 835, HES: 700, and RL: 670 ml). However, 35% of RL patients required blood products, compared with 62% (HA) and 64% (HES group; P=0.0003). Significantly, more study solution had to be administered in the RL group compared with the colloid groups. Total perioperative fluid balance was least positive in the HA group [6.2 (2.5) litre] compared with the HES [7.4 (3.0) litre] and RL [8.3 (2.8) litre] groups (P<0.0001). Both colloids affected clot formation and clot strength and caused slight increases in serum creatinine. CONCLUSIONS: Despite equal blood loss from chest drains, both colloids interfered with blood coagulation and produced greater haemodilution, which was associated with more transfusion of blood products compared with crystalloid use only.

Effect of cardiopulmonary bypass on regional antibiotic penetration into lung tissue.

The use of cardiopulmonary bypass (CPB) during cardiac surgery causes regional ventilation-perfusion mismatch, contributing to regional disturbances in antibiotic penetration into lung tissue. Ventilation-perfusion mismatch is associated with postoperative pneumonia, a frequent and devastating complication after cardiac surgery. In this prospective clinical animal study, we performed in vivo microdialysis to determine the effect of CPB on regional penetration of levofloxacin (LVX) into lung tissue. Six pigs underwent surgery with CPB (CPB group), and another six pigs underwent surgery without CPB (off-pump coronary artery bypass grafting; OPCAB group). LVX (750 mg) was administered intravenously to all pigs immediately after surgery. For regional measurements of LVX in pulmonary concentrations, microdialysis probes were inserted in both lungs of each pig. Pigs were placed in the right lateral position. Time versus concentration profiles of unbound LVX were measured in the upper and lower lung tissue and plasma in all pigs. In all pigs, maximum concentrations (Cmax) of LVX were significantly lower in the upper lung than in the lower lung (OPCAB, P = 0.035; CPB, P < 0.001). Median Cmax of LVX showed a significant difference in the upper versus lower lung in the CPB group (P < 0.05). No significant difference was found in the median Cmax of LVX in the upper and the lower lung in the OPCAB group (P = 0.32). Our data indicate that CPB affects perioperative regional antibiotic penetration into lung tissue. Common clinical antibiotic dosing schemes should be reevaluated in patients undergoing coronary artery bypass grafting with CPB.

Influenza A-induced cardiogenic shock requiring temporary ECMO support and urgent heart transplantation.

We report a case of a child with familial cardiomyopathy who contracted H1N1 influenza followed by cardiovascular collapse requiring immediate arteriovenous ECMO support. Despite the lack of experience with heart transplantation (HTx) soon after H1N1 infection, HTx was considered as an exit strategy since restoration of cardiac function was considered unlikely. In contrast to the most common indication for ECMO use in patients with H1N1 infection, early ECMO support in cases with infection-induced myocardial decompensation may be lifesaving. Additionally, this report shows that urgent heart transplantation in a patient on ECMO support can be performed safely after recent H1N1 infection and simultaneous heparin-induced thrombocytopenia, which has not been reported before. This case also indicates that H1N1 vaccination should be considered for potential transplantation candidates to prevent severe infection.

Validation of cardiac output measurement with the LiDCO™ pulse contour system in patients with impaired left ventricular function after cardiac surgery.

After cardiac surgery, patients with low left ventricular ejection fraction probably benefit the most from accurate monitoring of continuous cardiac output. Thirty patients with impaired ventricular function were studied, and intermittent bolus thermodilution and continuous pulse contour (LiDCO plus™) cardiac output compared. Following lithium dilution calibration, a total of 220 paired results were recorded. Thermodilution and LiDCO measurements ranged from 2.3 to 11.0 and 2.6 to 10.8 l.min(-1), respectively. Corresponding means (SD) were 6.1 (1.6) and 6.2 (1.9) l.min(-1), with coefficients of variance of 26 and 31%, respectively. The correlation coefficient was 0.82, bias 0.28 l.min(-1) with upper and lower limits of agreement 1.96 and -1.41 l.min(-1); the percentage error was 27%. LiDCO showed good correlation, marginal bias and acceptable limits of agreement and percentage error. It could therefore potentially replace thermodilution as a means of measuring cardiac output in the ICU, particularly when determination of pulmonary artery pressure is not required.