Bedside Assessment of Right Ventricular Output Lying in Prone Or Supine Position (BAROLO)

The BAROLO Study Bedside Assessment of Right Ventricular Output Lying in Prone Or Supine Position. Hemodynamic Changes Due to Prone Position in Patients After Cardiac Surgery - a Prospective Randomized Controlled Trial Evaluating the Effect of Prone Position on Right Heart Function

Right ventricular failure (RVF) is a common complication to cardiac surgery, which is associated to mortality, kidney failure, stroke, prolonged mechanical ventilation and ICU stay. The right ventricle is particularly vulnerable to an increased afterload. By increasing pulmonary vascular resistance (PVR), atelectasis might mitigate a negative effect on the right ventricle.

Recruitment maneuvers have been shown to resolve atelectasis and improve hemodynamics by increasing cardiac output and lowering PVR. However these maneuvers transiently raise airway pressures, which in turn increases right ventricular afterload, a situation often poorly tolerated by patients with RVF.

Prone position is used in patients with respiratory failure and has been shown to decrease mortality in patients with ARDS. Prone position decreases atelectasis and moves ventilation dorsally. In ARDS it also seems to mediate beneficial hemodynamic effects such as an increase in cardiac output and a decrease in PVR.

The investigators hypothesis is that prone position early after cardiac surgery will increase cardiac output by recruitment of atelectasis and thereby decrease PVR.

Study Overview

• Status: Not yet recruiting
• Conditions: Heart Failure; Cardiac Surgery; Cardiopulmonary Bypass; Vasoconstriction; Prone Position; Cardiac Output; Atelectasis; Respiratory Mechanics; Atelectases, Postoperative Pulmonary; Pulmonary Arterial Pressure; Right Ventricular Function; Recruitment Maneuver; Cardiac Surgery Recovery
• Intervention / Treatment: Procedure: Prone position

Detailed Description

Recruitment and consent:

Patients will be screened for participation no later than the day before surgery. Potential participants will be given written and verbal information regarding the study and time to ask questions and consider their participation.

Randomization:

After end of surgery, at baseline in the ICU, patients will be randomly allocated (1:1 ratio) to supine position and prone position. Block randomization with variable block sizes will be performed with sequentially numbered, opaque, sealed envelopes. All performed by Statistiska konsultgruppen. Patient stratification according to cardiac index at end-surgery will be performed to ensure similar allocation of patients with cardiac index <2.2 L/min/m2 in each group. The investigator who enrolls study participants will not have access to the random allocation sequence.

Sample Size:

Based on previous studies regarding cardiac surgery or prone position a power calculation was performed using a two-sample comparison of means, with equally sized independent groups. With an intention to detect a 20% difference in cardiac index in the intervention group and with 80% power, 0.05 α, estimated mean CI 2.6(0.8 SD) in control group, and CI 3.2 in the prone group, calcuation rendered n=70 divided in 2 equally large groups. As patients intermittently require recurring surgery due to i.e. bleeding, some patients will be excluded after inclusion. Based on this and the power analysis 80 patients will be included and randomized to supine position (n=40) and prone position (n=40).

Description of method:

In included patients, anesthesia will be performed with Propofol, Fentanyl and Sevoflurane. As per clinical routine patients will have a central venous catheter, 1-2 arterial catheters, TEE probe and endotracheal tube inserted. Study participants will also get a pulmonary artery catheter (PAC) inserted prior to surgery to facilitate measurement of cardiac output using thermodilution and PVR. Body surface area is calculated using the Mosteller formula.

During surgery, after CPB is weaned, the attending anaesthesiologist is instructed to refrain from additional recruitment maneuvers and a PEEP >8 cmH2O. Unless FiO2 is >80% to maintain adequate oxygenation of the patient or the anaesthesiologist deems it necessary.

When surgery is finished, the patient will be moved to the Thoracic ICU. Ventilation performed with a Maquet Servo-U (Getinge, SE) is set to volume control, tidal volumes of 6 ml/kg IBW with a respiratory rate of 12-18 and PEEP 8 cmH2O. Data collection occurs in all patients in supine position (0). Hereafter the study group is turned to prone while the control group remains in supine position.

60 minutes after proning data is again collected (t1), whereafter a recruitment maneuver is performed by gradually increasing PEEP during 2,5 minutes in 6 steps to 20 cmH2O during. After 30 seconds PEEP is decreased in 6 steps during 2,5 minutes to reach PEEP 8 cmH2O. Data is collected after the recruitment maneuver (t2) and one hour after (t3), adding up to a total of 2 hours and 15 minutes in supine or prone position. The patients in prone position are turned to supine position and the last data collection occurs (t4). In total 5 time points for data collection. Postoperative care will now continue as per routine care. Patients will be extubated as soon as possible according to clinical routine and eventually discharged from the ICU.

Since a recruitment maneuver transiently increases right ventricular afterload there is a possibility not all patients will tolerate the recruitment maneuver as described above. As per clinical practice the level of airway pressures during recruitment will be adjusted when needed to avoid adverse effects.

Discontinuation of the intervention:

In order to minimize harm the following set criteria will be used to discontinue prone position:

• Hemodynamic instability with increased Norepinephrine >0.7mcg/kg/min
• Sustained arrythmia which requires treatment including DC conversion
• Any condition which, in the judgement of the investigator, might increase risk of harm to the patient

Blinding:

After allocation to supine or prone position neither the investigator, nor ordinary ICU personnel, will be blinded due to safety and impracticalities. Patients are blinded due to being under general anaesthesia during randomization until weaning from mechanical ventilation (after the study protocol is completed).

Data collection:

A site investigator will record data using a software developed by Getinge from the respirator to a designated research computer. All other data and variables, mentioned above, will be collected from the participants digital chart and real time monitoring (Philips IntelliVue & BD Hemosphere).

Data management:

Collected data is pseudonymized and stored on a password protected designated research computer. Only authorized study personnel have access to the computer.

Original records, including signed written consent, are kept with strict confidence. These records will be kept in a secure, locked and limited access location at Sahlgrenska Univeristy Hospital during the study and after completion for an additional 10 years. At inclusion each patient is pseudonymized by receiving a participant ID, which is used in all data files.

• Study Type: Interventional
• Enrollment (Estimated): 80
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Viktor Erbring, MD; Phone Number: +46706456664; Email: viktor.erbring@vgregion.se
• Study Contact Backup: Name: Per Persson, MD, PhD; Phone Number: +46736467042; Email: per.persson@vgregion.se

Study Locations

• Sweden
  • Gothenburg, Sweden, 41345
    • Cardiac Intensive Care Unit
    • Contact: Viktor Erbring, MD; Phone Number: +46706456664; Email: viktor.erbring@vgregion.se

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Scheduled for cardiac surgery using cardiopulmonary bypass

Exclusion Criteria:

• BMI >40
• Emergency surgery
• In need of secondary surgery
• Advanced grown up congenital heart disease
• Pulmonary disease
• Hemodynamic instability with Norepinephrine >0.4mcg/kg/min
• Any condition which, in the judgement of the investigator, might increase the risk to the patient

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: Supine position; Control group. Will remain in supine position for the whole protocol.
Experimental: Prone position; Will be turned to prone position after baseline data collection (0) and return to supine position before the final data collection (t4).	Procedure: Prone position; Prone position is applied in the intervention group immediately after randomization, patients will be prone for a total of 2 hours and 15 minutes. During this time 3 data collection points occur (t1, t2 & t3).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cardiac Index	L/min/m2	1 hour after baseline

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
PVRi	Difference between and within groups	At baseline. 1 hour after baseline. 1 hour 15 minutes after baseline. 2 hours 15 minutes after baseline. 2 hours 45 minutes after baseline.
Cardiac Index	Difference between and within groups	At baseline. 1 hour after baseline. 1 hour 15 minutes after baseline. 2 hours 15 minutes after baseline. 2 hours 45 minutes after baseline.
PaO2:FiO2	Within and between groups	At baseline. 1 hour after baseline. 1 hour 15 minutes after baseline. 2 hours 15 minutes after baseline. 2 hours 45 minutes after baseline.
Driving Pressure	Plateau Pressure - PEEP	At baseline. 1 hour after baseline. 1 hour 15 minutes after baseline. 2 hours 15 minutes after baseline. 2 hours 45 minutes after baseline.
ICU length of stay	Time from start to end of the ICU visit, measured in days.	Perioperative
Time to extubation	Time from arrival to the ICU until patient's endotracheal tube is removed (extubation). Measured in hours.	Perioperative
Adverse events	Severity graded: Mild, Moderate & Severe Causality: Due to prone position? Other reason?	At any point in time from Baseline to 2 hours and 45 minutes after Baseline.
RV pressure	Looking at differences of right ventricular blood pressure between groups at all timepoints	At baseline. 1 hour after baseline. 1 hour 15 minutes after baseline. 2 hours 15 minutes after baseline. 2 hours 45 minutes after baseline.
Vasopressor dose	Difference of actual vasopressor dose within and between groups at all timepoints	At baseline. 1 hour after baseline. 1 hour 15 minutes after baseline. 2 hours 15 minutes after baseline. 2 hours 45 minutes after baseline.
Inotrope dose	Difference of actual inotrope dose between groups at all timepoints	At baseline. 1 hour after baseline. 1 hour 15 minutes after baseline. 2 hours 15 minutes after baseline. 2 hours 45 minutes after baseline.
CVP	Difference in central venous pressure within and between groups at all timepoints	At baseline. 1 hour after baseline. 1 hour 15 minutes after baseline. 2 hours 15 minutes after baseline. 2 hours 45 minutes after baseline.
PAP	Difference in pulmonary artery pressure within and between groups at all timepoints	At baseline. 1 hour after baseline. 1 hour 15 minutes after baseline. 2 hours 15 minutes after baseline. 2 hours 45 minutes after baseline.
PCWP	Difference in pulmonary capillary wedge pressure within and between groups at all timepoints	At baseline. 1 hour after baseline. 1 hour 15 minutes after baseline. 2 hours 15 minutes after baseline. 2 hours 45 minutes after baseline.
Systemic blood pressure	Difference in systemic blood pressure within and between groups at all timepoints	At baseline. 1 hour after baseline. 1 hour 15 minutes after baseline. 2 hours 15 minutes after baseline. 2 hours 45 minutes after baseline.
Heart rate	Difference in heart rate within and between groups at all timepoints	1 hour after baseline. 1 hour 15 minutes after baseline. 2 hours 15 minutes after baseline. 2 hours 45 minutes after baseline.

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
RV contractility during recruitment maneuver	Measured as dP/dt (mmHg/s). Maximum upslope of the pressure waveform measured at the RV.	During recruitment (1 hour after baseline).
Physiological dead space	Eventual exploratory outcome. Analysis of VD/VT using Enghoff-modified Bohr equations.	At baseline. 1 hour after baseline. 1 hour 15 minutes after baseline. 2 hours 15 minutes after baseline. 2 hours 45 minutes after baseline.
Subgroup analysis of Cardiac Index	Patients with perioperative or postoperative diagnosed RVF according to a published standardized definition will be analyzed separately in a subgroup analysis.	At baseline. 1 hour after baseline. 1 hour 15 minutes after baseline. 2 hours 15 minutes after baseline. 2 hours 45 minutes after baseline.
Subgroup analysis of PVRi	Patients with perioperative or postoperative diagnosed RVF according to a published standardized definition will be analyzed separately in a subgroup analysis.	At baseline. 1 hour after baseline. 1 hour 15 minutes after baseline. 2 hours 15 minutes after baseline. 2 hours 45 minutes after baseline.

Collaborators and Investigators

• Sponsor: Sahlgrenska University Hospital

Study record dates

Study Major Dates

• Study Start (Estimated): September 1, 2026
• Primary Completion (Estimated): May 1, 2028
• Study Completion (Estimated): October 1, 2028

Study Registration Dates

• First Submitted: March 24, 2026
• First Submitted That Met QC Criteria: June 3, 2026
• First Posted (Actual): June 8, 2026

Study Record Updates

• Last Update Posted (Actual): June 8, 2026
• Last Update Submitted That Met QC Criteria: June 3, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Cardiovascular Diseases; Heart Diseases; Respiratory Tract Diseases; Lung Diseases; Heart Failure; Pulmonary Atelectasis; Musculoskeletal Physiological Phenomena; Musculoskeletal and Neural Physiological Phenomena; Posture; Prone Position
• Other Study ID Numbers: 286380

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: As of now there aren't any plans to share IPD. However if good ideas for further studies on this data by other researchers appear, our plan to share IPD might change.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No