NMS. Surgery

28

Part I ♦ Foundations

B

IV solution in pressure bag

Pulmonary artery

Superior vena cava

G

Distal lumen of PA catheter

Monitor

G

A

Sterile sleeve of PA catheter

ECG PA RA

Sheath with side port

Proximal lumen

Cables

Distal lumen opening

Transducer, stopcock, flush device

Balloon inflated

C

E

Proximal infusion port Distal infusion port

Thermistor connector

D

F

Balloon inflation valve

E

Thermistor lumen opening

F

artery, the balloon is inflated and occludes antegrade blood flow, thereby allowing the distal port to measure retrograde pressure from the left atrium, an indirect measure of left ventricular preload. b. Thermodilution methodology: The catheter is able to determine CO by accurately measuring changes in blood temperature (thermodilution) after introduction of a known thermal challenge. Figure 1-3: Pulmonary artery ( PA ) catheter and pressure-monitoring systems. ( A ) Bedside monitor that connects with cables to ( B ) the pressure-monitoring systems (includes IV solution in a pressure bag, IV tubing, and two transducers with stopcocks and flush devices). This system connects to ( C ) the proximal infusion port that opens in the right atria and is used to infuse fluids or medications and monitor central venous pressures and ( D ) the distal infusion port. This port opens in the PA and is used to monitor PA pressures. ( E ) The thermistor connector is attached to the bedside cardiac monitor to obtain CO. ( F ) An air-filled syringe is attached to the balloon inflation valve during catheter insertion and measurement of PA wedge pressure. ( G ) PA catheter positioned in the pulmonary artery. Note the sterile sleeve over the PA catheter. The PA catheter is threaded through the sheath until it reaches the desired position in the PA. The side port on the sheath is used to infuse medications or fluids. ECG, electrocardiogram; RA, right atrium. (From Farrell M. Smeltzer and Bare’s Textbook of Medical-Surgical Nursing , 4th ed. Wolters Kluwer Health, 2016, Fig. 21-12.)