A mechanical prosthetic tricuspid or pulmonic valve are generally considered absolute contraindication for right hear catheterization. Relative contraindications for RHC include coagulopathy or thrombocytopenia (INR >1.7 or platelet count <50,000). The ability to temporary pace the patient with left bundle branch block should be available during RHC as flotation of the pulmonary artery (PA) catheter through the right ventricle can induce complete heart block in up to 3 % of these patients [3]. Patients with intra-cardiac devices, such as pacemakers or implantable cardiac defibrillators, should have RHC performed under fluoroscopy to avoid the catheter tip getting caught in or dislodging a device lead. The presence of severe tricuspid regurgitation, right ventricular dilatation, and pulmonary hypertension might also necessitate the use of fluoroscopic guidance.

The Swan Ganz PA catheter is the most widely used catheter for RHC. The balloon tip allows the catheter to follow the flow of venous blood through the right side of the heart to the PA. The catheter has multiple lumens that are accessed by various ports, including a proximal port, a distal port, and a balloon inflation port. These ports allow for the measurement of pressures as well as the sampling of blood oxygen saturation along the right side of the heart and the PA (Fig. 14.1). A thermistor mounted to the distal tip of the catheter allows for temperature measurements [1].

RHC can be performed via the superior vena cava with percutaneous entry through the internal jugular or subclavian veins, or via the inferior vena cava with percutaneous entry through the femoral veins. Internal jugular or subclavian approaches are less susceptible to infection and are less restraining to the patient and thus are preferred for bedside management. The right internal jugular approach is preferred over left as it provides a direct route to the right atrium (RA). The subclavian approach is preferred via the left side, again due to ease of catheter flotation [1].

Central venous access is obtained as described in the previous chapter. Prior to flotation, the system should be appropriately leveled and zeroed. Usually attached to a manifold, the transducer is placed at the level of the mid-axillary line in the fourth intercostal space (the approximate level of the right atrium) and zeroed by opening the system to room air. Each port of the PA catheter is then carefully flushed and full inflation of the balloon is confirmed. An air leak should be excluded by dipping the balloon in a sterile bowl of saline. If the PA catheter is to be left in place, it should first be inserted through a protective sterile sleeve. The PA catheter is then inserted through the central venous sheath to approximately 15 cm or until the RA waveforms are observed. The balloon is inflated and advanced gently. Fluoroscopy is used in the catheterization lab to direct placement; however, at the bedside, guidance is provided via the pressure waveforms (Fig. 14.2). Flotation of the PA catheter from the femoral vein is more difficult and usually requires fluoroscopic guidance [3, 4].

To minimize ventricular ectopy, the catheter should be passed rapidly through the right ventricle (RV) into the PA. From the PA the catheter is then advanced slowly to wedge position. In general, the PCWP tracing should be reached within 50–55 cm if the catheter is placed via the internal jugular or subclavian approaches. If the femoral approach is used, it should be reached at 65–70 cm. In cases of marked respiratory variation, the PCWP should be measured at end expiration. Once PCWP is recorded the balloon should be deflated and it should be verified that a clear PA tracing is obtained. The volume of air required to inflate the balloon for obtaining wedge should also be checked. If the volume is less than 1.5 cc, the catheter should be pulled back to avoid “over-wedging.” In the catheterization lab, to evaluate for the presence of intra-cardiac shunts, screening blood samples are usually drawn for oximetric analysis from the RA and the PA. Oximetric analysis can also be performed to confirm accurate wedge position by obtaining a blood sample with a saturation of ≥95 % [3, 4].

The PA catheter can determine CO by two techniques – the thermodilution technique and using the Fick principle to measure oxygen consumption. In performing the thermodilution technique, a syringe with 10 cc saline is attached to the proximal port, whose tip is located in the RA when the thermistor on the distal tip is in the PA. The entire volume of saline is rapidly injected within 4 s in a single, smooth effort. The change in temperature as recorded by the distal thermistor is plotted over time and the area under the curve is planimetered to calculate CO (in liters/min). At least three serial thermodilution measurements should be performed and averaged (more if there is substantial variability). Factors that interfere with normal flow of saline past the sensing thermistor, such as low CO, tricuspid regurgitation, and intra-cardiac shunts (i.e., atrial septal defect) can affect the accuracy of CO determination [4, 5].