6/10/1999Mansfield, MA Approximate calculation of needed pump speed (PS) t = Kt/V * V/K * 1000 K = Kt/V *V/t*1000 t = 1.3 *40/300*1000 = 173 min K = 1.3 *40/240 *1000 = 217 K = 1.3 *50/240 *1000 = 270 Pump speed vs. clearance with F-80 dialyzer PS = 400; Blood Flow = 360; K = 270

6/10/1999Mansfield, MA Approximate calculation of needed pump speed (PS) t = (Kt/V) * (V/K) * 1000 K = (Kt/V) *(V/t)*1000 t = 1.6 *(40/270)*1000 = 237 min K = 1.6 *(40/240) *1000 = 267 K = 1.6 *(50/240) *1000 = 333 Pump speed vs. clearance with F-80 dialyzer PS = 400; Blood Flow = 360; K = 270

6/10/1999Mansfield, MA Blood flow through the catheter n Design – Length – Diameter – Cross section n Tip location n Tip occlusion – Fibrin sheath – Ball thrombus – Mural thrombus

6/10/1999Mansfield, MA Catheter design Poiseuille’s equation Flow in catheters is directly proportional to the pressure difference and the 4th power of the lumen radius, and inversely proportional to the lumen length and the viscosity of fluid (blood) In lumens deviating from circular, resistance is higher (flow is lower at the same length and cross section)

6/10/1999Mansfield, MA

6/10/1999Mansfield, MA

6/10/1999Mansfield, MA Tip location n The best tip location is at the superior vena cava/right atrium junction n Flows are usually worse with other locations

6/10/1999Mansfield, MA Tip in right brachiocephalic vein

6/10/1999Mansfield, MA Tip in right brachiocephalic vein

6/10/1999Mansfield, MA Catheter tip in the mid-SVC

6/10/1999Mansfield, MA Tip in right atrium

6/10/1999Mansfield, MA Inflow in left brachicephalic vein Outflow in SVC against the wall

6/10/1999Mansfield, MA Inflow against wall Outflow tip

6/10/1999Mansfield, MA Tip low in atrium

6/10/1999Mansfield, MA Tip in the mid right atrium

6/10/1999Mansfield, MA Tip close to inferior vena cava Opti-Flow

6/10/1999Mansfield, MA Tip in right ventricle

6/10/1999Mansfield, MA Tip in right ventricle

6/10/1999Mansfield, MA Tip occlusion n Fibrin sheath (sleeve) - probably on all catheters – Asymptomatic – Poor or no inflow when involving catheter tip n Ball thrombus – A large clot adherent to the catheter tip but not to the vessel wall. n Difficult to dissolve, can be stripped n Mural thrombus – A large clot adherent to both catheter and vessel wall and causing partial or complete occlusion of the vessel

6/10/1999Mansfield, MA

6/10/1999Mansfield, MA Inflow tip occluded

6/10/1999Mansfield, MA Inflow tip occluded

6/10/1999Mansfield, MA Both tips occluded

6/10/1999Mansfield, MA Tip occlusion n Fibrin sheath (sleeve) - probably on all catheters – Asymptomatic – Poor or no inflow when involving catheter tip n Ball thrombus – A large clot adherent to the catheter tip but not to the vessel wall. n Difficult to dissolve, can be stripped n Mural thrombus – A large clot adherent to both catheter and vessel wall and causing partial or complete occlusion of the vessel

6/10/1999Mansfield, MA Ball thrombus removed with catheter

6/10/1999Mansfield, MA Ball thrombus, closer view