RESUMO
OBJECTIVES: To investigate whether measuring cardiac output and its course after cardiac surgery by a new analysis technique of radial artery pressure waves, without need for calibration (FloTrac/Vigileo [FV]; Edwards Lifesciences, Irvine, CA), conforms to the standard bolus thermodilution method via a pulmonary artery catheter (PAC). DESIGN: Prospective study. SETTING: Intensive care unit of university hospital. PARTICIPANTS: Twenty patients for up to 24 hours after cardiac surgery. INTERVENTIONS: Simultaneous and triplicate PAC thermodilution and FV cardiac output measurements at 1 and 3 hours after surgery and the following morning. MEASUREMENTS AND MAIN RESULTS: Fifty-six simultaneous measurement sets were obtained. Mean cardiac output (PAC) ranged between 2.8 and 10.3 L/min and for the FV method between 3.3 and 8.8 L/min. The coefficient of variation for pooled measurements was 7.3% for the PAC and 3.0% for the FV method. For pooled data, the r2 was 0.55 (p < 0.001), with a bias of -0.14, precision of 1.00 L/min, and 95% limits of agreement between -2.14 and 1.87 L/min in a Bland-Altman plot. Also, the FV method tended to overestimate cardiac output when <7 L/min and increased with time, whereas mean arterial pressure increased and PAC cardiac output did not change. Changes in cardiac output correlated (r2 = 0.52, p < 0.001). CONCLUSIONS: The FV arterial pressure waveform analysis method is a clinically applicable method for cardiac output assessment without calibration, after cardiac surgery. It performs well at low cardiac outputs but remains sensitive to changes in vascular tone.
Assuntos
Pressão Sanguínea/fisiologia , Débito Cardíaco/fisiologia , Idoso , Calibragem , Procedimentos Cirúrgicos Cardíacos , Cateterismo de Swan-Ganz/instrumentação , Cateterismo de Swan-Ganz/métodos , Feminino , Humanos , Masculino , Monitorização Fisiológica/métodos , Estudos Prospectivos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Termodiluição/métodosRESUMO
BACKGROUND: Transient, subclinical myocardial, renal, intestinal, and hepatic tissue injury and impaired homeostasis is detectable even in low-risk patients undergoing conventional cardiopulmonary bypass (CPB). Small extracorporeal closed circuits with low priming volumes and optimized perfusion have been developed to reduce deleterious effects of CPB. METHODS: A prospective, randomized trial was conducted in 49 patients undergoing elective coronary artery bypass graft surgery either with the use of a standard or mini-CPB system (Synergy). We determined early postoperative inflammatory response (leukocytosis, C-reactive protein, urine interleukin-6), platelet consumption and activation (urine thromboxane B2), proximal renal tubular injury (urine N-acetyl-glucosaminidase), and intestinal injury (intestinal fatty acid binding protein). RESULTS: In patients undergoing coronary artery bypass grafting with a mini-CPB system, we observed decreased priming volumes with subsequent attenuation of on-pump hemodilution, improved hemostatic status with reduced platelet consumption and platelet activation, decreased postoperative bleeding and minimized transfusion requirements. We also found reduced leukocytosis and decreased urinary interleukin-6. Levels of urine N-acetyl-glucosaminidase were on average threefold lower, and urinary intestinal fatty acid binding protein was 40% decreased in the patients on the mini-CPB system, as compared with standard CPB. CONCLUSIONS: The use of the mini-CPB system during myocardial revascularization represents a viable nonpharmacologic strategy that can attenuate the alterations in the hemostatic system, reduce bleeding and transfusion requirements, decrease systemic inflammatory response, and reduce immediate postoperative renal and intestinal tissue injury.