DK2985_C000 1..28 - AlSharqia Echo Club

Echocardiography During Cardiac Surgery 291(A)(B)IVCCARDIOPLEGIACANNULARACARDIOPLEGIA(C) CANNULAIVCLARALVRV(D)(E)IVCRETROGRADECARDIOPLEGIACANNULA(F) RETROGRADECARDIOPLEGIACANNULAIVCRASVCRAFigure 13.7 Retrograde cardioplegia cannula malpositioned in the outlet of the inferior vena cava (IVC) during cardiopulmonarybypass in a 64-year-old woman undergoing revascularisation. Low-esophageal 08 (A–C) and 908 (D–F) view (LA, left atrium; LV,left ventricle; RA, right atrium; RV, right ventricle; SVC, superior vena cava).ostial abnormalities, The Thebesian valve, small or stenoticsinus from previous procedures are present (Fig. 13.6).In these circumstances, TEE can assist cannulation,confirm and monitor adequate catheter placement(Fig. 13.7) (19). Transesophageal echocardiography mayalso identify coronary sinus injury, leading to atrioventriculargroove hematoma. This usually results fromhigh perfusion pressure, traumatic stylet-guided catheterinsertion and perforation of the coronary sinus wall orlaceration due to balloon overinflation or overpressurizationduring retrograde cardioplegia infusion (20).E. Vents and Venous CanulationProper functioning of vents and the venous cannulationcatheter during CPB is both confirmed by surgical palpationand on TEE by the observing emptied right and left ventricularcavities (Fig. 13.8). During double venous cannulation(Fig. 13.9), malposition of the IVC cannula in a suprahepaticvein leads to decreased venous return to the CBPreservoir and left ventricular drainage (Fig. 13.10): oncerecognized, this is easily corrected by repositioning underTEE. Repositioning of a venous cannula during femorofemoralCPB has also been described (9) as well as a longaortic cannula in the aortic arch (Fig. 13.11) or to confirmadequate guidewire positioning in the true lumen duringaortic dissection (Figs. 13.12 and 13.13).III. CARDIAC PHYSIOLOGY ANDPROCEDURES BEFORECARDIOPULMONARY BYPASSA. Controlled VentilationThe hemodynamic effects of mechanical ventilation on theright and left ventricular function are complex and interrelated.They depend on the tidal volume, the amount ofpositive-pressure and the underlying baseline right andleft ventricular function. The effects of positive-pressure