RCIS common mistakes
RCIS · Understand the traps and how to avoid them.
Calculating Fick cardiac output or indexed values without first converting units consistently (e.g., mixing mL/min with L/min, or using BSA in m² versus cm²).
Formulas are memorized as symbol strings and applied under time pressure; candidates forget that oxygen consumption is in mL/min while output is reported in L/min, and that cardiac index requires dividing by body surface area.
What to do instead
Before computing, write the target unit next to each variable and convert once at the start; rehearse a single worked example (VO2 in mL/min, AV O2 difference in mL O2 per 100 mL blood, factor of 10) until the conversion is automatic.
Treating a thermodilution cardiac output as valid when the indicator curve is abnormal (low injectate volume, prolonged transit, irregular rhythm), rather than recognizing the tracing is uninterpretable.
The numeric result displays regardless of curve quality, so candidates accept the number instead of inspecting the curve shape and reproducibility of triplicate measurements.
What to do instead
Adopt the habit of reviewing the thermodilution curve and the spread among three injections; if values vary widely or the curve is flattened or prolonged, state the measurement is unreliable and use an alternative method such as Fick.
Misclassifying a hemodynamic profile because pulmonary capillary wedge pressure is assumed to equal left ventricular end-diastolic pressure in every patient.
Simplified teaching equates the two, so candidates ignore conditions that decouple them, such as mitral stenosis, aortic regurgitation, or high intrathoracic pressure.
What to do instead
When the clinical picture and wedge pressure conflict, explicitly consider decoupling causes and integrate the full profile (right atrial pressure, pulmonary artery pressure, wedge, output, and systemic vascular resistance) before naming a state.
Using a single pressure reading to characterize a lesion instead of measuring the gradient across the valve or stenosis with simultaneous or pullback recordings.
Candidates report the peak chamber pressure they see on the monitor and stop there, forgetting that the diagnostic information is the difference between two chambers.
What to do instead
For any suspected stenosis or shunt, plan the paired measurement in advance (which two pressures, simultaneous versus pullback) and interpret the mean gradient rather than only the peak-to-peak difference.
Underestimating contrast volume and radiation dose accumulation across a multi-vessel case because each individual injection is judged acceptable in isolation.
Dose and volume are tracked per run, not cumulatively, so the total creeps past safe thresholds without anyone noticing.
What to do instead
Announce a running total of contrast volume and dose-area product after each major injection, and set a pre-procedure ceiling tied to the patient's renal function before the case begins.
Selecting an angiographic projection that foreshortens or overlaps the segment of interest, then interpreting the image as if the vessel were fully profiled.
Standard default views are used reflexively without reasoning about which view opens the target segment, and foreshortening mimics a shorter or narrower vessel.
What to do instead
Before each injection, state which segment is being evaluated and which projection profiles it; add an orthogonal view whenever a lesion appears in only one plane.
Failing to identify the correct catheter position on fluoroscopy before injecting or measuring, such as a catheter tip in the coronary sinus, aortic sinus, or a branch rather than the intended chamber.
Pressure waveform and fluoroscopic appearance are read separately rather than together, so a plausible-looking tracing from the wrong location is accepted.
What to do instead
Confirm position using both the pressure waveform morphology and the fluoroscopic landmark every time the catheter is advanced or repositioned, and recheck after any guidewire or catheter exchange.
Misidentifying a coronary artery or its branches on angiography, particularly distinguishing the left anterior descending from a diagonal or the right coronary from a conus or acute marginal branch.
Vessel identification relies on a memorized pattern rather than tracing the vessel through its course across multiple frames and views.
What to do instead
Trace each vessel from ostium to distal segment across successive frames and confirm with an orthogonal view; if a branch cannot be followed confidently, label it uncertain rather than assigning a name.
Overlooking a contraindication or required adjustment before a procedure, such as continuing an anticoagulant, inadequate hydration before contrast, or unrecognized renal impairment.
Checklists are reviewed in a rush and the pre-procedure assessment is treated as paperwork rather than a decision point.
What to do instead
Work through a fixed pre-procedure review (anticoagulation, renal function, allergies, hydration, access-site assessment) and verbally confirm each item before the patient enters the room.
Failing to recognize and respond to a vagal or hemodynamic reaction during sheath removal or access-site manipulation, attributing the change to anxiety instead of a physiologic reflex.
The focus stays on the technical task, and early signs such as bradycardia and falling blood pressure are noted but not acted on.
What to do instead
Treat any bradycardia with hypotension during sheath manipulation as a vagal response until proven otherwise: stop the stimulus, position the patient, and escalate while monitoring the rhythm.