Reliability of thermodilution derived cardiac output with different operator characteristics

Area of Science:

• Cardiovascular Physiology
• Medical Device Technology
• Clinical Measurement

Background:

• Cardiac output (CO) is crucial for assessing hemodynamic status.
• Thermodilution is a common method for CO measurement during right heart catheterisation (RHC).
• Inter-operator variability in thermodilution CO measurements is not well-quantified.

Purpose of the Study:

• To assess inter-operator variability of the thermodilution technique for CO measurement.
• To identify operator characteristics influencing CO measurement accuracy.
• To compare thermodilution-derived CO with a calibrated mock circulation loop (MCL).

Main Methods:

• Utilized a mock circulation loop (MCL) with calibrated flow sensors to generate controlled CO levels (3.0–7.0 L/min).
• 15 participants (cardiologists, cardiology trainees, ICU consultants) performed thermodilution CO measurements.
• Recorded participant characteristics (experience, BMI, grip strength) and compared them to MCL-calibrated CO.

Main Results:

• Participants generally overestimated CO by a mean difference of +0.75 ± 0.71 L/min.
• The overall correlation between actual and measured CO was strong (r² = 0.85).
• Accuracy improved significantly with increased RHC experience, higher BMI, and decreased grip strength.

Conclusions:

• Thermodilution is a reasonable technique for CO determination.
• Operator experience is the primary factor linked to CO measurement accuracy.
• Adequate training and exposure to thermodilution are essential for clinicians performing RHC.