The pulmonary artery catheter (Swan-Ganz) is a standard tool in intensive care for measuring and monitoring cardiac index by thermodilution. The Swan-Ganz IQ™ model also allows continuous estimation of cardiac index through analysis of the right ventricular pressure wave, which could be useful for rapidly assessing changes in cardiac output during volume expansion response tests. However, the concordance between this continuous method and thermodilution remains poorly studied in real clinical conditions and may vary depending on certain clinical situations. This study therefore aims to compare the cardiac index measured by thermodilution with that estimated by right ventricular pressure waveform analysis based on data collected in clinical practice.

The pulmonary artery catheter (or Swan-Ganz catheter) is a standard tool for measuring and monitoring cardiac index in intensive care. It measures cardiac index using thermodilution, which is considered the gold standard method. The Swan-Ganz IQ™ model also offers continuous measurement of cardiac index by analyzing the right ventricular pressure waveform. The ability to measure cardiac output continuously would allow pulmonary artery catheterization to be used to assess cardiac output during short procedures, such as tests to predict the response to volume expansion (passive leg raising, expiratory pause), and to evaluate its effect on cardiac index. However, the concordance between cardiac output measured by thermodilution (reference method) and that estimated by the continuous method based on analysis of the right ventricular pressure waveform remains poorly evaluated by independent data in real clinical conditions. Furthermore, this agreement may vary depending on the clinical situation, particularly in the presence of right ventricular dysfunction, tricuspid regurgitation, or left heart failure. In this context, this study aims to compare the cardiac index measured by thermodilution with the cardiac index estimated by analyzing the right ventricular pressure waveform, based on data collected in the clinical setting.

Inclusion Criteria:

• Age ≥ 18 years
• Hospitalization in intensive care
• Presence of a Swan-Ganz IQ™ pulmonary artery catheter placed as part of treatment
• Thermodilution performed by the clinician in charge as part of treatment

Exclusion Criteria:

• Pregnancy
• Legal protective measures (guardianship, conservatorship, and deprivation of liberty by court/administrative decision)
• Refusal of participation by the patient's relatives or the patient themselves.
• Cardiac output measurements by thermodilution or continuous cardiac output analysis that cannot be used.

Patients hospitalized in medical ICU (of Bicêtre and Angers) with pulmonary arterial catheter (PAC) place as part of routine clinical care.