Fontan Physiology Ventilation Strategy

Study Overview
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Brief Summary
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This study will investigate the different tidal volume (Vt) strategies during a cardiac catheterization procedure to determine whether or not low or high Vt have an impact on cardiac output. Research question: While maintaining the same minute ventilation/PaCO2, does higher Vt (10 cc/kg)/lower rate vs. lower Vt (6 cc/kg)/higher rate (maintaining consistent PEEP) result in improved cardiac output?

Detailed Description
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The trial will be a randomized crossover design. The study cohort will be randomized (50/50) to begin with either low Vt or high Vt ventilation. After achieving steady state, initial cardiac output measurements will be made using a measured oxygen consumption (VO2) and the Fick principle, per routine clinical protocol. Following baseline assessment of cardiac output and hemodynamics (which is standard of care for all catheterization procedures), participants will be transitioned to the alternative ventilation modality (high Vt or low Vt). After a 5-minute equilibration period, oxygen saturations and VO2 measurements will be re-acquired, to determine cardiac output and hemodynamics in this second state.

Official Title
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Impact of Fontan Ventilation Strategy on Cardiac Output: An Invasive Physiologic Cross-over Study

Conditions
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Anesthesia, Congenital Heart Disease

Intervention / Treatment
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* Procedure: Low Vt protocol
* Procedure: High Vt protocol


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients of UPMC Children's Hospital of Pittsburgh that have Fontan physiology (single heart ventricle) that are presenting as outpatients to undergo a cardiac catheterization with general endotracheal anesthesia for purpose of diagnosis or interventional cath. Parents and/or guardians willing to provide informed consent. Exclusion Criteria: Those unwilling to give consent and those patients who do not have Fontan physiology. Any urgent/emergent catheterization procedure will be excluded. Any Fontan patient having a cardiac catheterization under monitored anesthesia care (as opposed to general endotracheal anesthesia) will not be eligible. Inability to undergo cardiac catheterization. Pregnant women will be excluded. < 6 weeks post-op from Fontan completion surgery Same hospitalization as Fontan completion surgery Intrinsic pulmonary disease which would be anticipated to impact study protocol / findings Fontan completion surgery performed at age > 7 years
Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Supportive Care
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: The trial will be a randomized crossover design.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Low transition to High Vt protocol<br>This arm of the study will begin with lower tidal volumes at higher respiratory rates for initial hemodynamic measurements. They will then be transitioned to the higher tidal volume at lower respiratory rate condition for repeat hemodynamic measurement. | Procedure: Low Vt protocol<br>* Low Vt protocol - tidal volumes (Vt) 6 ml/kg, respiratory rate required for end tidal carbon dioxide (EtCO2) of 36-38 mmHg, PEEP 5 centimeter of water (cm-H20) , I:E ratio 1:2<br>Procedure: High Vt protocol<br>* High Vt protocol - tidal volumes (Vt) 10 ml/kg, respiratory rate required for EtCO2 of 36-38 mm Hg, PEEP 5 cmH2O, I:E ratio 1:3.<br>|
| Experimental: High transition to Low Vt protocol<br>This arm of the study will begin with higher tidal volumes at lower respiratory rates for initial hemodynamic measurements. They will then be transitioned to the lower tidal volume at higher respiratory rate condition for repeat hemodynamic measurement. | Procedure: Low Vt protocol<br>* Low Vt protocol - tidal volumes (Vt) 6 ml/kg, respiratory rate required for end tidal carbon dioxide (EtCO2) of 36-38 mmHg, PEEP 5 centimeter of water (cm-H20) , I:E ratio 1:2<br>Procedure: High Vt protocol<br>* High Vt protocol - tidal volumes (Vt) 10 ml/kg, respiratory rate required for EtCO2 of 36-38 mm Hg, PEEP 5 cmH2O, I:E ratio 1:3.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cardiac Output | The investigators will assess cardiac output using the Fink principle for each arm of randomization. | Measurements will occur at the 5-minute equilibration period into the ventilation strategy. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pulmonary blood flow | The investigators will compare blood flow in both arms. | Measurements will occur at the 5-minute equilibration period into the ventilation strategy. | 
| Systemic blood pressure | The investigators will assess the vital sign in both intervention arms. | Measurements will occur at the 5-minute equilibration period into the ventilation strategy. | 
| Pulmonary arterial pressure | The investigators will assess pressures in both intervention arms. | Measurements will occur at the 5-minute equilibration period into the ventilation strategy. | 
| Pulmonary vascular resistance | Completed using pulmonary vascular resistance (PVR) equation from measurements obtained during the cardiac catheterization. | Measurements will occur at the 5-minute equilibration period into the ventilation strategy. | 
| Systemic vascular resistance | This will be calculated using appropriate equations using measurement obtained during catheterization procedure. | Measurements will occur at the 5-minute equilibration period into the ventilation strategy. |