Effects of Different Fresh Gas Flows on Carboxyhemoglobin Levels and Postoperative Patient Outcomes in Pediatric Cardiovascular Surgery

Study Overview
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Brief Summary
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Low flow anesthesia; It is an anesthesia practice in which, after absorbing at least 50% of the exhaled air and carbon dioxide (CO2) using a semi-closed rebreathing system, the unused anesthetic gases are mixed with a certain amount of fresh gas and then completely or partially returned to the patient in the next inspiration. Theoretically, when low flow anesthesia is compared to high or normal flow anesthesia; it is known to have advantages such as using less inhalation agent, preserving mucociliary activity, preventing microatelectasis, preserving the amount of moisture, and reducing temperature loss. In studies conducted in different fresh gas flows, it has been observed that CO, which is thought to accumulate in the body by rebreathing in a closed circuit, increases as a result of the chemical interaction and dry CO2 absorbent. However, there is no evidence in these studies that low-flow anesthesia increases CO accumulation and alters hemodynamics. In our clinic, low-flow and high-flow anesthesia technics are both being used. In this study, we aimed to evaluate the effects of high- and low-flow sevoflurane anesthesia applied with a closed system on perioperative carboxyhemoglobin (COHb) levels and hemodynamic system in pediatric cardiovascular surgery cases.

Official Title
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Effects of Different Fresh Gas Flows on Carboxyhemoglobin Levels

Conditions
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Low Flow Anesthesia, High Flow Anesthesia

Intervention / Treatment
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* Other: low and high flow


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients between the ages of 2 months and 7 years undergoing elective cardiac surgery American Society of Anesthesiology (ASA) score II ve III patients Exclusion Criteria: Patients undergoing emergency surgery Patients who need mechanical ventilation or any respiratory support before the operation Patients with left to right shunt cyanotic patients Patients younger than 2 months and older than 7 years

Ages Eligible for Study
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Minimum Age: 2 Months
Maximum Age: 7 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Low-flow anesthesia group<br>In this group, ventilation parameters is adjusted to have fresh gas flow/minute ventilation ratio below 0.5 | Other: low and high flow<br>* low and high flow anesthesia are both being used. The effects of different gas flows will be evaluated.<br>|
| High-flow anesthesia group<br>In this group, ventilation parameters is adjusted to have fresh gas flow/minute ventilation ratio above 1.0 | Other: low and high flow<br>* low and high flow anesthesia are both being used. The effects of different gas flows will be evaluated.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| COHb levels | COHb values will be measured in arterial blood gas samples at different fresh gas flow levels. | at the 30th minute of the surgery, at the beginning of cardiopulmonary bypass, at the time of chest closure, at the time of intensive care unit admission | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| extubation time | the time of extubation | at the time that patient is extubated up to 24 hours | 
| body temperature | body temperature | at the 30th minute of the surgery, at the beginning of cardiopulmonary bypass, at the time of chest closure, at the time of intensive care unit admission | 
| bleeding | Total amount of bleeding during the first 24 hours | 24 hours | 
| vasoactive inotrope score (VIS) | VIS at the end of the operation | postoperative first hour |