Goal-Directed Therapy Following Cardiac Surgery

Rationale:

Goal-directed therapy (GDT) has been shown to reduce complications and length of stay on cardiac surgery patients. Unfortunately, the existing literature on GDT in CV surgery has several limitations, which creates uncertainty over the expected benefit of implementing this care element with high associated costs and impact on workflow. Hypotension Prediction Index (HPI) is a proprietary algorithm that utilizes pulse contour analysis from invasive arterial pressure monitoring to identify patients at risk for becoming hypotensive within 15 minutes. The algorithm was developed using machine learning on a large surgical/ICU data set, and then externally validated on non-cardiac and cardiac surgical patients. HPI, as part of a GDT algorithm, may allow healthcare providers to identify patients recovering from cardiac surgery who may benefit from optimization prior to becoming hypotensive and assist with selecting the most appropriate hemodynamic intervention.

Hypothesis:

Application of an HPI-based GDT algorithm will result in a difference in cumulative fluid administration over the first 24-hours of index ICU admission following cardiac surgery.

Study Design:

Unblinded randomized controlled trial pilot. Data will be used to inform/justify the feasibility, design, and implementation of a future multi-center randomized controlled trial.

Study Population:

Moderate or high-risk (EuroSCORE II > 2%), non-emergent, adult open-heart cardiac surgery patients. Heart transplant, durable VAD implantation, or patients who require post-operative MCS support will be excluded.

Sample size= 100 (50 control : 50 intervention)

Intervention:

Patients randomized to the intervention arm will be monitored using the HPI technology and be treated following a GDT algorithm when HPI is >50 for 48-hours or duration of invasive arterial monitoring (whichever occurs first). The GDT algorithm is a standardized approach to identifying abnormal hemodynamic parameters and administering a prescribed therapy in a step-wise fashion with fixed re-assessment intervals (see attached).

What will be different from routine care? :

• Hemodynamic interventions (fluid, inotropic, or vasopressor therapy) will be administered when HPI > 50 rather than MAP < 65.
• Choice of applied therapy (fluid, inotropic, or vasopressor therapy) will be guided by a GDT algorithm.

Inclusion criteria

• ≥ 18 years of age
• Planned cardiac surgery using cardiopulmonary bypass (sternotomy or MICS)
• Preoperative European System for Cardiac Operative Risk Evaluation II (EuroSCORE II) of 2% or more.
• Informed consent obtained.

Exclusion criteria

• Emergency surgery
• Patients who refuse participation
• Patients who are unable to give informed consent
• Patients who are having a heart or lung transplant.
• Surgery for insertion of any ventricular assist device
• Aortic arch procedures with any degree of debranching or hybrid with endovascular intervention in the ascending aorta +/- arch.
• Patients who require MCS (including ECMO, Impella, or IABP) post-operatively
• Patients on contact/droplet isolation.
• Patients deemed excessively unstable and/or complex by their attending intensivist on arrival to the ICU.
• If the post-operative arterial line MAP goal is not 65 mmHg.
• Patients who suffer intra-operative mortality.