Influence of body core temperature on blood loss and transfusion requirements during off-pump coronary artery bypass grafting: a comparison of 3 warming systems.

BACKGROUND: The aim of this prospective randomized trial was to evaluate the efficacy of 3 intraoperative warming systems (Warm-Touch, Thermamed SmartCare OP system, and Allon 2001) on maintenance of normothermia and to investigate their effects on perioperative bleeding and transfusion requirements in patients undergoing off-pump coronary artery bypass grafting. METHODS: With institutional approval/patient informed consent, 90 patients presenting for elective multiple off-pump coronary artery bypass grafting were randomly assigned to 1 of the 3 warming systems. Active warming was started after the induction of anesthesia. Perioperative transfusion was based on international guidelines. Body core temperature was recorded every 30 minutes during operation. Perioperative blood loss, autotransfusion, and allogenic transfusions were recorded. Analysis of variance was performed with post hoc Scheffé tests and chi 2 tests. RESULTS: Normothermia could be sufficiently maintained during operation by the Allon 2001 only. Final body core temperature was 34.7 degrees C +/- 0.9 degrees C (Warm-Touch), 35.6 degrees C +/- 0.8 degrees C (Thermamed SmartCare OP), and 36.5 degrees C +/- 0.4 degrees C (Allon 2001; P < .001, Warm-Touch vs Thermamed SmartCare OP, Warm-Touch vs Allon 2001, and Thermamed SmartCare OP vs Allon 2001). Perioperative blood loss was 2683 +/- 1049 mL (Warm-Touch), 2300 +/- 788 mL (Thermamed SmartCare OP), and 1497 +/- 497 mL (Allon 2001; P = .195, Warm-Touch vs Thermamed SmartCare OP; P < .001, Warm-Touch vs Allon 2001; P = .001, Thermamed SmartCare OP vs Allon 2001). Transfusion requirements were 1097 +/- 874 mL (Warm-Touch), 986 +/- 744 mL (Thermamed SmartCare OP), and 431 +/- 387 mL (Allon 2001; P = .838, Warm-Touch vs Thermamed SmartCare OP; P = .003, Warm-Touch vs Allon 2001; P = .013, Thermamed SmartCare OP vs Allon 2001). Free of allogenic transfusion were 15 (51.7%; Warm-Touch), 18 (60%; Thermamed SmartCare OP), and 24 (82.8%; Allon 2001) patients ( P = .037). CONCLUSIONS: The goal of normothermia during off-pump coronary artery bypass grafting was best achieved by the Allon system. With this concept, overall blood loss and transfusion requirements were reduced, hence indicating improved quality of perioperative care.

Volumetric preload measurement by thermodilution: a comparison with transoesophageal echocardiography.

BACKGROUND: End-diastolic volume indices determined by transpulmonary thermodilution and pulmonary artery thermodilution may give a better estimate of left ventricular preload than pulmonary capillary wedge pressure monitoring. The aim of this study was to compare volume preload monitoring using the two different thermodilution techniques with left ventricular preload assessment by transoesophageal echocardiography (TOE). METHODS: Twenty patients undergoing elective cardiac surgery with preserved left-right ventricular function were studied after induction of anaesthesia. Conventional haemodynamic variables, global end-diastolic volume index using the pulse contour cardiac output (PiCCO) system (GEDVI(PiCCO)), continuous end-diastolic volume index (CEDVI(PAC)) measured by a modified pulmonary artery catheter (PAC), left ventricular end-diastolic area index (LVEDAI) using TOE and stroke volume indices (SVI) were recorded before and 20 and 40 min after fluid replacement therapy. Analysis of variance (Bonferroni-Dunn), Bland-Altman analysis and linear regression were performed. RESULTS: GEDVI(PiCCO), CEDVI(PAC), LVEDAI and SVI(PiCCO/PAC) increased significantly after fluid load (P<0.05). An increase >10% for GEDVI(PiCCO) and LVEDAI was observed in 85% and 90% of the patients compared with 45% for CEDVI(PAC). Mean bias (2 SD) between percentage changes (delta) in GEDVI(PiCCO) and deltaLVEDAI was -3.2 (17.6)% and between deltaCEDVI(PAC) and deltaLVEDAI -8.7 (30.0)%. The correlation coefficient (r2) for deltaGEDVI(PiCCO) vs deltaLVEDAI was 0.658 and for deltaCEDVI(PAC) vs deltaLVEDAI 0.161. The relationship between deltaGEDVI(PiCCO) and deltaSVI(PiCCO) was stronger (r2=0.576) than that between deltaCEDVI(PAC) and deltaSVI(PAC) (r2=0.267). CONCLUSION: GEDVI assessed by the PiCCO system gives a better reflection of echocardiographic changes in left ventricular preload, in response to fluid replacement therapy, than CEDVI measured by a modified PAC.

[R-hirudin (lepirudin, refludan) as an alternative anticoagulant in heparin-induced thrombocytopenia during cardiopulmonary bypass connection]. / R-Hirudin (Lepirudin, Refludan) als alternatives Antikoagulans bei Heparin-induzierter Thrombozytopenie während des Anschlusses an den extrakorporellen Kreislauf.

A 72-year-old patient with heparin-induced thrombocytopenia (HIT) and global cardiac decompensation underwent cardiac surgery using an extracorporeal circuit (ECC). For systemic anticoagulation r-Hirudin (lepirudin, Refludan) was administered as a heparin substitute during extracorporeal circuit. During cardiopulmonary bypass (100 min) the concentration of r-Hirudin was between 2.9 and 4.6 mcg/ml under continuous infusion of r-Hirudin at between 1.5 and 4.5 mcg/kg/min. The operation was successful and during its course no abnormal bleeding or fibrin formation in the extracorporeal circuit was observed. One hour after operation haemorrhage occurred and rethoracotomy was performed without discovering the cause of the surgical bleeding. After substitution with fresh frozen plasma, thrombocytes and Prothromblex the bleeding stopped on the operation day. The further postoperative course was uncomplicated. After 3 days the patient came to nursing station and was discharged from hospital to a rehabilitation centre after 13 days. After a further 3 weeks he went home in a good general condition.

Pressure gradients across bileaflet aortic valves by direct measurement and echocardiography.

BACKGROUND: Pressure gradients calculated from echo-cardiography after aortic valve replacement are commonly much higher than would be expected from in vitro measurements. METHODS: The mean, peak-to-peak, and maximal gradients across bileaflet aortic prostheses (St. Jude Medical) were measured invasively in 52 patients at high and low heart rate, cardiac index, and stroke volume. One week after operation the gradients were calculated from a standard transthoracic echocardiogram (delta p = 4v2(2)). In a second study 3 to 12 months later, gradients were calculated using the standard, simplified Bernoulli equation, and with the equation considering subvalvular flow velocities (delta p = 4(v2(2-)v1(2)). Invasive and echocardiographic measurements were matched and compared. RESULTS: Invasively measured mean gradients for 21 to 29-mm valves ranged from 7.4 +/- 4.9 to 4.3 +/- 1.6 mm Hg at systolic flow rates from 11.3 +/- 0.7 to 16.2 +/- 1.8 L.min-1.m-2. Mean echocardiographic gradients were 15.1 +/- 4.5 to 7.5 +/- 2.2 mm Hg (p < 0.001) with the standard method, and 10.5 +/- 1.9 to 5.6 +/- 1.5 mm Hg when considering the subvalvular flow velocity (p < 0.001). CONCLUSIONS: Mean gradients across bileaflet prostheses are generally low, even in small valves and with high systolic flow. The correlation of the invasive in vivo with in vitro gradients is good. Standard echocardiography overestimates gradients across bileaflet heart valves and high gradients are not due to valve dysfunction. Gradients obtained by echocardiography considering the subvalvular flow velocity correlate better to invasively measured and in vitro gradients.