RV dysfunction has been associated with increased mortality in the ICU and cardiac surgical patients. Thus, early identification of RV dysfunction at less severe stages will allow for earlier intervention and potentially better patient outcomes. However, so far, no studies have reported prospectively the prevalence of abnormal RV pressure waveform during cardiac surgery and in the ICU. Our primary hypothesis is that the prevalence of abnormal RV pressure waveform occurs in more than 50% of cardiac surgical patients throughout their hospitalization. Those patients with abnormal RV pressure waveform will be more prone to post-operative complications related to RV dysfunction and failure in the OR and ICU.

The pulmonary artery catheter (PAC) consists of an intravenous device placed in the pulmonary artery to measure cardiac output, pulmonary artery pressures (Richard C, 2011) as well as cardiac filling pressures. Since its initial presentation by Swan in 1970 (H J Swan, 1970), several modifications were made on the initial catheter now allowing continuous assessment of cardiac output, continuous monitoring of stroke volume (SV), systemic vascular resistance (SVR) and mixed venous saturation (SvO2) (Arora, 2014) (H J Swan, 1970) (Richard C, 2011). We intend to enhance current Swan-Ganz catheters with clinical decision support tools to early identify hemodynamically unstable states that can lead to further deterioration of the patient's health state.

Right ventricular (RV) dysfunction is mostly associated to a decrease in contractility, right ventricular pressure overload or right ventricular volume overload (François Haddad, 2008). RV dysfunction can occur in several clinical scenarios in the intensive care unit (ICU) and operating room (OR): pulmonary embolism, acute respiratory distress syndrome (ARDS), septic shock, RV infarction, and in pulmonary hypertensive patients undergoing cardiac surgery (François Haddad, 2008). RV dysfunction has been associated with increased mortality in the ICU and cardiac surgical patients (André Y. Denault, 2006) (Denault AY B. J.-S., 2016). Thus, early identification of RV dysfunction at less severe stages will allow for earlier intervention and potentially better patient outcomes. Unfortunately, identifying which patients will develop RV dysfunction and then progress towards RV failure have proven difficult. One of the reasons for delaying the diagnosis of RV dysfunction could be the lack of uniform definition, especially in the perioperative period. Echocardiographic definitions of RV dysfunction have been described in previous studies: RV fractional area change (RVFAC) < 35 %, tricuspid annular plane systolic excursion (TAPSE) < 16 mm, tissue Doppler S wave velocity <10 cm/s, RV ejection fraction (RVEF) <45% and RV dilation have been related to RV dysfunction (Rudski LG, 2010). However, these echocardiographic indices cannot be continuously monitored and are insufficient in describing RV function. The diagnosis of fulminant RV failure is more easily recognized as a combination of echocardiographic measures, compromised hemodynamic measures and clinical presentation (Raymond M, 2019) (François Haddad, 2008) (Haddad F, 2009). RV dysfunction is inevitably associated with absolute or relative pulmonary hypertension because of the anatomic and physiological connection between the RV and pulmonary vascular system (Naeije R, 2014) (François Haddad, 2008). The gold standard for measuring pulmonary pressure is still the pulmonary artery catheter. However, RV output can initially be preserved despite of pulmonary hypertension (Denault AY C. M., 2006). It is therefore mandatory that early, objective, continuous, easily obtainable and subclinical indices of RV dysfunction are found and validated to initiate early treatment of this disease.

Since 2002, Dr Denault's group at Montreal Heart Institute has been using continuous RV pressure waveform monitoring initially for the diagnosis of RV outflow tract obstruction (Denault A, 2014) and then for RV diastolic dysfunction evaluation (St-Pierre P, 2014) (Myriam Amsallem, 2016). Preliminary data based on a retrospective study on 259 patients found that 110 (42.5%) patients had abnormal RV gradients before cardiopulmonary bypass (CPB).Abnormal RV diastolic pressure gradient was associated with higher EuroSCORE II (2.29 [1.10-4.78] vs. 1.62 [1.10-3.04], p=0.041), higher incidence of RV diastolic dysfunction using echocardiography (45 % vs. 29 %, p=0.038), higher body mass index (BMI) (27.0 [24.9-30.5] vs. 28.9 [25.5-32.5], p=0.022), pulmonary hypertension (mean pulmonary artery pressure (MPAP) > 25 mmHg) (37 % vs. 48 %, p=0.005) and lower pulmonary artery pulsatility index (PAPi) (1.59 [1.19-2.09] vs. 1.18 [0.92-1.54], p<0.0001). Patients with abnormal RV gradient had more frequent difficult separation from CPB (32 % vs. 19 %, p=0.033) and more often received inhaled pulmonary vasodilator treatment before CPB (50 % vs. 74 %, p<0.001). However, this was retrospective and limited to the pre-CPB period.

In 2017, in a review article on RV failure in the ICU (Hrymak C, 2017), RV pressure waveform monitoring using the paceport of the pulmonary artery catheter was recommended as a simple method of monitoring RV function (Rubenfeld GD, 1999). However, no studies have reported prospectively the prevalence of abnormal RV pressure waveform during cardiac surgery and in the ICU.

Inclusion Criteria:

• Be ≥ 18 years of age
• Participate in the Informed Consent process and sign/date the approved informed consent forms
• Projected to receive Swan-Ganz catheter as part of procedure/standard of care with intermittent cardiac output and mixed venous oxygen saturation (SvO2) measures

Exclusion Criteria:

• Refuse to sign consent
• Have left bundle branch block
• Have recurrent sepsis
• Have hypercoagulopathy
• Allergic to FORE-SIGHT Elite sensor adhesive
• Latex allergy due to presence of latex in the Swan-Ganz catheter balloon.

Subjects ≥ 18 years of age, with planned surgery or liver transplantation, projected to receive Swan-Ganz as part of the procedure/standard of care with intermittent cardiac output measures will be screened for inclusion into the Study. Only subjects meeting all inclusion criteria will be enrolled.