Comparison of the ability of esCCO and Volume View to measure trends in cardiac output in patients undergoing cardiac surgery.

BACKGROUND: Cardiac output (CO) is a physiological variable that should be monitored during cardiac surgery. The purpose of this study was to assess the trending ability of two CO monitors, esCCO (Nihon Kohden™, Tokyo, Japan) and Volume View (VV) (Edwards Lifesciences, Irvine, USA). METHODS: A total of 19 patients were included in the study. Before cardiopulmonary bypass (CPB), CO was measured simultaneously using both esCCO and VV devices before and after three CO-modifying manoeuvres (passive leg raise [PLR], the end expiratory occlusion test [EEOT] and positive end expiratory pressure [PEEP] at 10 cm H2O). Five CO values for esCCO and three for VV were averaged and compared during a one-minute period of time before and after each manoeuvre. RESULTS: A total of 114 paired readings were collected. Median CO values were 4.3 L min⁻¹ (IQR: 3.8; 5.2) and 3.8 L min⁻¹ (IQR: 3.5; 4.5) for esCCO and VV, respectively. The precision error was 1.4% (95% CI:1.0-1.7) for esCCO and 2.2% (95% CI: 1.8-2.7) for VV. The bias between esCCO and VV values was normally distributed (P = 0.0596). Between esCCO and VV, the mean bias was +0.6 L min⁻¹ with a Limit of Agreement (LOA) of -1.8 L min⁻¹ and +3.0 L min⁻¹. The concordance rate was 43% (95% CI: 29-58) between esCCO and VV. CONCLUSION: Both single and trended measurements of CO using esCCO and VV were not in agreement. This large discrepancy leads one to the conclusion that any outcome study conducted with one of these devices cannot be applied to the other.

Tranexamic acid decreases the magnitude of platelet dysfunction in aspirin-free patients undergoing cardiac surgery with cardiopulmonary bypass: a pilot study.

This study sought to compare the effect of tranexamic acid (TXA) administration on cardiopulmonary bypass-induced platelet dysfunction in patients who received preoperative aspirin or not. We performed a prospective, randomized, double-blind pilot study, including patients undergoing elective cardiac surgery with cardiopulmonary bypass (CPB). Patients without aspirin interruption were enrolled in the 'group ASPIRIN' (n = 18) and those who had never been treated with aspirin were included in the 'group NO ASPIRIN' (n = 10). Patients were then randomized to receive either TXA or the same infusion of normal saline. Multiple electrode aggregometry was used to assess platelet function at the different time points throughout the surgery: baseline, post-TXA loading dose, aortic unclamping (End CPB), and 5 min after protamine (Protamine). Compared to those included in the group NO ASPIRIN, patients included in the group ASPIRIN presented a decreased baseline platelet function measured by ASP test (P < 0.01) and collagen test (P < 0.01). In the group NO ASPIRIN, treatment group (TXA vs. placebo) significantly influenced the results for ADP test (P < 0.01), thrombin receptor-activating peptide test (P = 0.01), and ASP test (P = 0.01). We observed that TXA improved platelet function, as measured using multiple electrode aggregometry on ADP test, thrombin receptor-activating peptide test, and ASP test, at the end of CPB (P < 0.05). TXA might decrease the magnitude of platelet dysfunction in aspirin-free patients undergoing cardiac surgery. Further studies are needed to confirm these results and assess a potential relationship with clinical endpoints.

Effect of two doses of tranexamic acid on fibrinolysis evaluated by thromboelastography during cardiac surgery: a randomised, controlled study.

BACKGROUND: Tranexamic acid is used to decrease bleeding and transfusions during cardiac surgery. However, dosing based on pharmacokinetic data to optimally inhibit fibrinolysis is unknown. With increasing concerns regarding seizures associated with higher doses, lower dosing schemes may be important. OBJECTIVE: To determine the effect of two dosing schemes compared with placebo on fibrinolysis and clinical outcomes. DESIGN: A double-blind, randomised, controlled, pilot trial. SETTING: Single tertiary centre. PATIENTS: Cardiac surgery patients requiring cardiopulmonary bypass. INTERVENTION: Patients were randomised to receive a 30 mg  kg(-1) bolus and continuous infusion of 16  mg  kg (-1) h(-1) (Group HIGH), a 5 mg  kg(-1) bolus followed by 5 mg  kg(-1)  h(-1) (Group LOW) or Sodium chloride (Placebo). MAIN OUTCOME MEASURE: Fibrinolysis was evaluated by thromboelastography and D-dimers. Secondary endpoints were blood loss, transfusion requirement and side effects. RESULTS: Thirty-three patients were included. Significant fibrinolysis was defined by LY30 more than 7.5% based on thromboelastography and was not observed after cardiopulmonary bypass in any groups. After protamine administration, LY30 differences between groups were 0.7 [95% confidence interval (95% CI) -0.04 to 1.4] between Groups HIGH and Placebo, -0.08 (95% CI -0.82 to 0.66) between Groups HIGH and LOW, and 0.78 (95% CI 0.02 to 1.5) between Groups LOW and Placebo. A significant increase in D-dimers was observed in the Group Placebo compared with the two treatment groups. There were no differences in bleeding or transfusion requirement. CONCLUSION: In this dose-finding study, there were no differences in fibrinolysis or clinical outcomes among the two tranexamic acid schemes and placebo. Any difference in fibrinolytic inhibition requires a larger adequately powered study. TRIAL REGISTRATION: EudraCT number: 2010-024104-99.

Review of the fibrinolytic system: comparison of different antifibrinolytics used during cardiopulmonary bypass.

Antifibrinolytic agents are often used in different clinical situations, especially in cardiac surgery. During several years, aprotinin was the drug of choice because more than antifibrinolytic properties, aprotinin offers a direct effect on kallikrein and inflammatory pathways. In 2008, The Blood Conservation Using Antifibrinolytics in a Randomized Trial (BART) initiated a discussion about real risks associated with aprotinin administration. Tranexamic acid and epsilon-aminocaproic acid appear to be interesting alternatives in our daily practice. The exact mechanism of action, the pharmacokinetic parameters, the efficacy, and the safety profile need to be clarified for lysine analogs. In this review, the different antifibrinolytics will be described with a special interest into the route of work, and recent patents. Current studies about the pharmacokinetic and the pharmacodynamic profile will be described, and finally the benefit-to-risk balance in patients undergoing cardiac surgery with cardiopulmonary bypass will be discussed.