Off-pump coronary artery bypass grafting(OP-CABG) has revolutionized the surgical approach for the treatment ofcoronary artery disease. OP-CABG avoids the use of extracorporeal circulation,and hence all the detrimental effects of instituting cardiopulmonary bypass(CPB), especially the systemic inflammatory response syndrome, are eliminatedin patients who undergo this technique of coronary revascularization. Essentialto the performance of OP-CABG is the use of mechanical stabilizers, for exampleoctopus II and/or starfish, which make the distal anastomotic site immobileduring grafting. In addition to mechanical stabilization, manipulation of theheart to provide access to the distal anastomotic site is necessary foroptional visualization.
Use of mechanical stabilizers and manipulation of theheart for optimal position prior to grafting makes the hemodynamic stateunsteady and is associated with fall in cardiac output (CO) and systemichypotension. Hemodynamic assessment involving CO measurement is of particularimportance in patients undergoing OP-CABG. The intermittent thermodilutionbolus techniques using a pulmonary artery catheter is still accepted as astandard method for measurement of CO, despite its invasive character and associatedrisks. Recently, less invasive methods and hardware to assess CO have becomeavailable.
One of these alternatives is the FloTrac/Vigileo system (EdwardsLife sciences, Irvine, California, United States), which determines CO by analyzingthe peripheral arterial waveform of an artery. FloTrac is easy to install, safeto use, and does not need any specific catheter or external calibration.FloTrac is based on the following equation: stroke volume (SV) = pulsatility ×kappa. Pulsatility is calculated by using the standard deviation (SD) of aperipheral arterial pressure wave.
Kappa is a number that represents thevascular tone of the patient’s arterial tree, and it takes [CE1] into account the age, weight, height, andsex.The FloTrac sensor has been proven accurateand reliable in monitoring CO in clinical studies when compared againstcontinuous cardiac output (CCO) and intermittent cardiac output (ICO).1 A prior study found satisfactory agreement ofthe new device with intermittent and continuous thermodilution.2 Good agreement was found between CO valuesobtained by arterial pulse contour analysis and thermodilution technique usingPAC in the intraoperative period in patients undergoing OP-CABG.3 Rose-Marieke have demonstrated that COmeasured by a new arterial pressure waveform analysis using FloTrac/Vigileo is clinicallyapplicable after cardiac surgery and performs well at low CO.4 [CE1]AU:Is this rewording better for sense?
