Effect of Heated Breathing Circuit on Intraoperative Core Temperature and Systemic Inflammation After Brain Surgery: a Prospective Randomized Study

Study Overview
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Brief Summary
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Mechanical respiration during general anesthesia causes cold and dry gases to reach the lower airway, reduce the function of the airway mucosa, and cause accumulation of secretions. Inhaled dry gas is one of the causes of hypothermia during general anesthesia. To overcome this, the warm-humidifying breathing circuit uses warm, moisture-preserving gas to promote mucus mobility of the airway mucosal ciliate cells and prevents cold gases from evaporating from the mucosal surfaces which results lowering body temperature. We aimed to investigate the effect of newly developed Sohum warm humidifying respiration circuit (SH501) on the prevention of core body temperature reduction during surgery and systemic inflammation reaction.

Official Title
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Effect of Heated Breathing Circuit on Intraoperative Core Temperature and Systemic Inflammation After Brain Surgery: a Prospective Randomized Study

Conditions
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Patients Scheduled for Brain Surgery

Intervention / Treatment
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* Device: conventional circuit
* Device: conventional humidification circuit
* Device: new humidifaction heat circuit


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: age ≥ 19 scheduled for brain surgery Exclusion Criteria: age < 19 patients with severe obstructive lung disease and/or restrictive lung disease patients patients with infectious disease surgery with prone position or lateral position arrhythmia

Ages Eligible for Study
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Minimum Age: 19 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: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: group C<br>general circuit group | Device: conventional circuit<br>* The patient enters the operating room without any pretreatment and attaches a standard patient monitoring device. Anesthesia was performed by intravenous anesthesia. After induction of anesthesia, alveolar recruitment is performed in supine position in all groups with 30 cmH2O for 5 seconds. Mechanical ventilator was set with tidal volume of 8 ml / kg, the inspiratory/ expiratory ratio of 1: 2 and respiratory rate was adjusted for targeting EtCO2 around 35mmHg. Keep the fresh air flow of the ventilator at 3 L / min and set the temperature to 37 ° C for the heating circuits of group H and group SH. An arterial cannulation and subclavian jugular vein catheter is inserted. The circuits were applied to each group as follows; conventional circuit or group C, conventional humidification circuit for group H and new humidification heat circuit for group SH, respectively. All other conditions were same among three groups.<br>* Other names: group C for control group (n=39);|
| Active Comparator: group H<br>warm circuit group | Device: conventional humidification circuit<br>* The patient enters the operating room without any pretreatment and attaches a standard patient monitoring device. Anesthesia was performed by intravenous anesthesia. After induction of anesthesia, alveolar recruitment is performed in supine position in all groups with 30 cmH2O for 5 seconds. Mechanical ventilator was set with tidal volume of 8 ml / kg, the inspiratory/ expiratory ratio of 1: 2 and respiratory rate was adjusted for targeting EtCO2 around 35mmHg. Keep the fresh air flow of the ventilator at 3 L / min and set the temperature to 37 ° C for the heating circuits of group H and group SH. An arterial cannulation and subclavian jugular vein catheter is inserted. The circuits were applied to each group as follows; conventional circuit or group C, conventional humidification circuit for group H and new humidification heat circuit for group SH, respectively. All other conditions were same among three groups.<br>* Other names: group H for conventional humidification circuit (n = 39);|
| Experimental: group SH<br>new warm circuit group | Device: new humidifaction heat circuit<br>* The patient enters the operating room without any pretreatment and attaches a standard patient monitoring device. Anesthesia was performed by intravenous anesthesia. After induction of anesthesia, alveolar recruitment is performed in supine position in all groups with 30 cmH2O for 5 seconds. Mechanical ventilator was set with tidal volume of 8 ml / kg, the inspiratory/ expiratory ratio of 1: 2 and respiratory rate was adjusted for targeting EtCO2 around 35mmHg. Keep the fresh air flow of the ventilator at 3 L / min and set the temperature to 37 ° C for the heating circuits of group H and group SH. An arterial cannulation and subclavian jugular vein catheter is inserted. The circuits were applied to each group as follows; conventional circuit or group C, conventional humidification circuit for group H and new humidification heat circuit for group SH, respectively. All other conditions were same among three groups.<br>* Other names: group SH for new humidifaction heat circuit (n=39);|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| core temperature |  | every 30 minute after induction of anesthesia until the end of anesthesia | 
| upper airway temperature |  | every 30 minute after induction of anesthesia until the end of anesthesia | 
| upper airway humidity |  | every 30 minute after induction of anesthesia until the end of anesthesia | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| cytokine level | pg/ml for Cytokine level(TNF-a, IL-1, IL-6, IL-8, IL-10) | 1, 30, 60, 90, 120, 150, 180, 210, 240 minute after induction and 1 second after the operation | 
| dead space | % for Deadspace(Vd/Vt) | every 30 minute after induction of anesthesia until the end of anesthesia | 
| intrapulmonary shunt | Qs/Qt, | every 30 minute after induction of anesthesia until the end of anesthesia | 
| respiratory variables | mmHg for respiratory variables(PaO2, PaCO2, PvO2, PvCO2) | every 30 minute after induction of anesthesia until the end of anesthesia | 
| compliance | L/cmH2O for compliance(△V/△P) | every 30 minute after induction of anesthesia until the end of anesthesia |