Marino The ICU Book 4e, IE

136 Hemodynamic Monitoring

Features The basic features of a PA catheter are shown in Figure 8.1. The catheter is 110 cm long and has an outside diameter of 2.3 mm (about 7 French). There are two internal channels: one channel emerges at the tip of the catheter (the distal or PA lumen), and the other channel emerges 30 cm proximal to the catheter tip, which should be situated in the right atrium (the proximal or RA lumen). The tip of the catheter has a small inflatable balloon (1.5 mL capacity) that helps to carry the catheter to its final des- tination (as just described). When the balloon is fully inflated, it creates a recess for the tip of the catheter that prevents the tip from damaging the vessel wall as the catheter is advanced. A small thermistor (a tempera- ture-sensing transducer) is placed near the tip of the catheter. This device is involved in the measurement of cardiac output, as described later in the chapter. Placement The PA catheter is inserted through a large-bore (8–9 French) introducer sheath that has been placed in the subclavian vein or internal jugular vein (see Figure 8.1). The distal lumen of the catheter is attached to a

Introducer Catheter

RA Lumen

Inflated Balloon

PA Lumen

Thermistor

FIGURE 8.1 The basic features of a pulmonary artery (PA) catheter. Note that the PA catheter has been threaded through a large-bore introducer catheter that has a side-arm infusion port.