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CO2 (Carbon Dioxide) - Cerebral Oxygenation

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT03338907
Recruitment Status : Completed
First Posted : November 9, 2017
Last Update Posted : February 20, 2019
Information provided by (Responsible Party):
University of Zurich

Brief Summary:

Several projects in high altitude research in environments with a low oxygen partial pressure (hypobaric hypoxia) leading to hypoxemia showed, that cerebral perfusion and cerebral performance could be improved by adding C02 (cabon dioxide).

The investigators hypothesize that adding 5% C02 to 02 (Oxygen) also under normobaric conditions increases the time until a significant cerebral hyopxia is measured by near infrared spectroscopy (NIRS) compared to the administration of 95% 02.

lf this hypothesis proves to be true, this approach might be used in situations in which individuals are prone to cerebral hypoxia. In bariatric surgery, patients that experience an apnea phase are more prone to (cerebral) hypoxia due to the fact, that they have a higher body mass index (BMI) leading to a reduced functional residual capacity (FRC), which serves as the oxygen reserve in the body.

Condition or disease Intervention/treatment Phase
Hypoxia, Brain Drug: Oxycarbon (5% CO2+ 95% O2) Phase 2

Detailed Description:

On the day of surgery patients will be randomized. After induction of anesthesia and endotracheal intubation patients will be managed by the study team to perform the intervention and the measurements.

According to randomization, investigational medical product (IMP) or comparator will be administrated by ventilator 1/ventilator 2.

At time point 1 apnea will be performed by disconnecting the ventilator from the endotracheal tube until the NIRS value has dropped by 20% from baseline. After that, re-ventilation will be resumed immediately, until parameters have returned to baseline.

During apnea time NIRS and vital signs will be recorded permanently, blood samples will be drawn at definite time points.

Application of IMP (or comparator) will be performed in this cross-over study design in the same manner after the baseline level is reached again.

At the end of the study procedure, after the baseline level of end-expiratory CO2 is reached again, patient will be taken over by the clinical anesthesia team and surgeons.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 30 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Intervention Model Description: Controlled, randomized, single blind, crossover
Masking: Single (Participant)
Masking Description: The sequence whether the IMP or the comparator is applied first will be randomly assigned using the web-based randomizer.
Primary Purpose: Treatment
Official Title: Anesthesia vs Aviation: Does Added Carbon Dioxide in Normobaric Hypoxia Have the Same Effect on Cerebral Oxygenation as in Hypobaric Hypoxia?
Actual Study Start Date : January 25, 2018
Actual Primary Completion Date : October 26, 2018
Actual Study Completion Date : February 12, 2019

Resource links provided by the National Library of Medicine

Arm Intervention/treatment
Experimental: Oxycarbon (5% CO2 + 95% O2)
Patients will be mechanical ventilated with Oxycarbon (5%CO2 +95% O2) after normocapnia is reached until FeO2 is stable for at least 1 min ≥ 80%. At timepoint 1 immediately prior apnea NIRS and vital parameters will be registered and an bloodsample will be drawn.
Drug: Oxycarbon (5% CO2+ 95% O2)
Oxycarbon will be administered by mechanical ventilation

Placebo Comparator: Control (95% O2)
Same procedure as arm "active comparator"
Drug: Oxycarbon (5% CO2+ 95% O2)
Oxycarbon will be administered by mechanical ventilation

Primary Outcome Measures :
  1. Time to decrease of tissue oxygenation index by 20 % [ Time Frame: 1 Day ]
    Parameter will be measured by NIRS

Secondary Outcome Measures :
  1. PaO2 (Oxygen partial pressure) [ Time Frame: 1 Day ]
    Parametere will be measured by arterial bloodgas

  2. SpO2 (oxygen saturation) [ Time Frame: 1 Day ]
    Parametere will be measured by arterial bloodgas

  3. PCO2 ( partial pressure of carbon) [ Time Frame: 1Day ]
    Parametere will be measured by arterial bloodgas

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 65 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Patients who are designated for bariatric surgery at the University Hospital Zurich (USZ)
  • Informed Consent as documented by signature
  • BMI >35 kg/m2

Exclusion Criteria:

  • Severe end-organ damage: chronic obstuctive pulmonary disease (COPD) GOLD (cassification) III and IV, known hepatic insufficiency or elevated liver enzymes, renal creatinine clearance <30ml/min
  • Severe cardiovascular disease (NYHA classification III and IV)
  • Known pulmonary Hypertension
  • Cerebrovascular disease
  • Pregnancy and lactation
  • Cardiac dysrhythmias
  • acidosis, chronic pulmonary disease
  • Known or suspected non-compliance, drug or alcohol abuse

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT03338907

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University Hospital Zurich
Zurich, Switzerland
Sponsors and Collaborators
University of Zurich
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Principal Investigator: Martin Schläpfer, MD, M.Sc. University of Zurich
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Responsible Party: University of Zurich Identifier: NCT03338907    
Other Study ID Numbers: 2017-01790
First Posted: November 9, 2017    Key Record Dates
Last Update Posted: February 20, 2019
Last Verified: February 2019
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No
Plan Description: Ist not planned to share data with other researchers

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Product Manufactured in and Exported from the U.S.: No
Keywords provided by University of Zurich:
cerebral hypoxia
cerebral perfusion
Additional relevant MeSH terms:
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Hypoxia, Brain
Signs and Symptoms, Respiratory
Signs and Symptoms
Brain Diseases
Central Nervous System Diseases
Nervous System Diseases