Right Heart Catheterization Basics Pressures and Waveforms Andr

Right Heart Catheterization Basics Pressures and Waveforms André C. Lapeyre, III, M. D. Andre Lapeyre, MD © Mayo Clinic

Right Heart Catheterization Pressures and Waveforms Basics Zeroing Notice that with the pressure channel turned off, the zero line is gray. Andre Lapeyre, MD The pressure transducer is then carefully positioned at the level of the patient’s mid-chest. The recording channel is turned on. The blue pressure reads exactly zero. © Mayo Clinic

Right Heart Catheterization Pressures and Waveforms Basics Zeroing An accurate mid-chest zero is critically important as small differences in right atrial, right (or left) ventricular end diastolic, and pulmonary capillary wedge pressures can make large differences in both the diagnosis and the treatment of a patient. Andre Lapeyre, MD © Mayo Clinic

Right Heart Catheterization Pressures and Waveforms Basics Zeroing – electronic drift If there is any question or concern, the zero should be rechecked whenever making critical measurements during the case. The electronics of fluid filled systems can and those of pressure sensor tipped catheters are likely to “drift” or change zero over time. Rechecking zero is often appropriate. Andre Lapeyre, MD © Mayo Clinic

Right Heart Catheterization Pressures and Waveforms Basics Artifact There are several types of artifact in waveforms about which to be aware. • • • Over damping Under damping Catheter whip Catheter impact End pressure Some of this may be inherent in the system being used but much is under the operator’s control. Important to recognize and correct as much as possible as they cause measurement inaccuracies. Andre Lapeyre, MD © Mayo Clinic

Right Heart Catheterization Pressures and Waveforms Basics Correct Overdamped Underdamped Correct – true systolic and diastolic pressures with accurate waveforem Overdamped – loss of true high and low pressures with smoothed wave Underdamped – exaggerated high and low pressure with spiked waves Andre Lapeyre, MD © Mayo Clinic

Right Heart Catheterization Pressures and Waveforms Basics Catheter whip and catheter impact artifact look much the same. High frequency, very spiked, and usually irregular looking waves. Andre Lapeyre, MD © Mayo Clinic

Right Heart Catheterization Pressures and Waveforms Basics End Pressure Artifact Occurs when a catheter with only an end-hole is pointed into (“upstream” rather than across or with “downstream”) the flow or jet. Can increase the measured pressure by significant amounts if the flow is very rapid/high velocity. Andre Lapeyre, MD © Mayo Clinic

Right Heart Catheterization Pressures and Waveforms Basics Overdamping – Large bubble in the system Aspirate and flush the system Clot, blood, contrast in the system Aspirate and flush the system Kink in catheter or tubing Fluoro the length of the catheter and check tubing - unkink Loose connection Check for leaks and tighten all connections Soft, compliant tubing Change to short, non-compliant tubing Andre Lapeyre, MD © Mayo Clinic

Right Heart Catheterization Pressures and Waveforms Basics Underdamping – Small bubble in the system Aspirate and flush the system System electronics underdamped Increase amplifier filter System underdamped with correct electronic filter Shorten tubing Remove extra connectors or stopcocks No clear source Increase fluid viscosity – tiny amounts of diluted contrast or blood into tubing/catheter. Be careful not to cause overdamping. Change transducer. Use manometer tipped catheter Andre Lapeyre, MD © Mayo Clinic

Right Heart Catheterization Pressures and Waveforms Basics Whip/Impact – Hyperdynamic/Tachycardic Sedation and pain relief Consider negative chronotropes Poorly positioned catheter Reposition catheter Impact external to patient Check for patient tremors Ensure no one is touching catheter or tubing. Make sure room, equipment, etc. vibration isn’t reaching transducer. No clear source Consider using manometer tipped catheter Andre Lapeyre, MD © Mayo Clinic

Right Heart Catheterization Pressures and Waveforms Basics Atrial A Andre Lapeyre, MD C V © Mayo Clinic

Right Heart Catheterization Pressures and Waveforms Basics Atrial Andre Lapeyre, MD X Y © Mayo Clinic

Right Heart Catheterization Pressures and Waveforms Basics Normal Right Atrial Pressure Always note the pressure scale (these are not overly prominent X and Y descents – appear magnified due to pressure scale) RA mm. Hg – normal 0 -6, mild 7 -11, moderate 12 -16, severe >16 Andre Lapeyre, MD © Mayo Clinic

Right Heart Catheterization Pressures and Waveforms Basics Normal Right Ventricular Pressure RVEDP RV mm. Hg – normal systolic < 35, diastolic 0 -2, end-diastolic ≤ 5 End-diastolic pressure is measured as the “a” wave falls but before the upstroke of the ventricular pressure. Note the minor underdamping – do not measure the spikes Andre Lapeyre, MD © Mayo Clinic

Right Heart Catheterization Pressures and Waveforms Basics Normal Pulmonary Artery Pressure PA mm. Hg – normal systolic < 35, mild 35 -44, moderate 45 -54, severe >55 PA mm. Hg mean – normal <25, mild 25 -34, moderate 35 -44, severe >45 Note the minor underdamping and minor dysrhythmia – do not measure the irregular beats. This tracing 22/10 with mean 14 (note scale) Andre Lapeyre, MD © Mayo Clinic

Right Heart Catheterization Pressures and Waveforms Normal Pulmonary Capillary Wedge Pressure PCW (Wedge) mm. Hg – normal < 15, mild 15 -19, moderate 20 -24, severe >24 PA mm. Hg mean – normal <25, mild 25 -34, moderate 35 -44, severe >45 Note the good X and Y descents. However, the wedge must be confirmed with oxygen saturation to be certain that it is not a partial wedge. Also, note the respiratory variation. The mean wedge pressure should be measured on the end expiratory beats. This tracing ~ 6 mm. Hg (note scale) Andre Lapeyre, MD © Mayo Clinic

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