Respiratory Effects of Dopamine in the Perioperative Care

Study Overview
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Brief Summary
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Dopamine is frequently used as an inotropic drug to elevate cardiac output. In addition to the beneficial cardiac effect of this drug, the few previous studies addressing its ability to alter the airway tone reported controversial results. Thus, the investigators aimed at clarifying the potential of dopamine to alter gas exchange outcomes and the airway tone in patients undergoing cardiac surgeries with cardiopulmonary bypass. Blood gas parameters, airway resistance, tissue damping and tissue elastance will be measured in the patients before the CPB, immediately after CPB, and 5 min after administration of dopamine (3 mcg/kg/min). The importance of the research is to reveal whether the beneficial mechanical changes after dopamine administrations are associated with improvements in gas exchange outcomes. Clarification of this research question have scientific relevance and may also improves patient outcomes.

Official Title
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Respiratory Effects of Dopamine in the Perioperative Care

Conditions
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Dopamine, Bronchodilation, Heart, Surgery, Functional Disturbance

Intervention / Treatment
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* Drug: Dopamine administration


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Cardial surgery patients undergoing cardiopulmonary bypass procedures Exclusion Criteria: Chronic respiratory diseases, elderly (>80 years)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 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: Treatment
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Dopamine group<br>Cardiac surgery patients receiving dopamine to support their cardiac function (as part of the routine post-operative care). | Drug: Dopamine administration<br>* Administration of dopamine (3 mcg/kg/min) as part of cardiac support therapy after the cardiopulmonary bypass. Administration of dopamine is a subject of clinical decision based on the cardiovascular status of the patients.<br>|
| No Intervention: Control group<br>Cardiac surgery patients receiving no positive inotrope drug. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Arterial oxygen partial pressure (PaO2) | Partial pressure of oxygen in the blood sample assessed by a blood gas analyser. | 5 min after administration of dopamine | 
| Arterial carbon dioxide partial pressure (PaCO2) | Partial pressure of carbon dioxide in the blood sample assessed by a blood gas analyser. | 5 min after administration of dopamine | 
| Lung mechanics | Airway resistance, lung tissue damping and lung tissue elastance obtained by forced oscillation technique. | 5 min after administration of dopamine | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Capnography | Time capnography to obtain phase 3 and phase 2 slopes. | 5 min after administration of dopamine | 
| Intrapulmonary shunt | Intrapulmonary shunt obtained by the Berggren shunt equation from arterial and central venous blood samples. | 5 min after administration of dopamine |