CO2 (Carbon Dioxide) - Cerebral Oxygenation

Hypoxia, Brain Clinical Trial

Official title:

Anesthesia vs Aviation: Does Added Carbon Dioxide in Normobaric Hypoxia Have the Same Effect on Cerebral Oxygenation as in Hypobaric Hypoxia?

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT03338907
• Other study ID #: 2017-01790
• Status: Completed
• Phase: Phase 2
• Start date: January 25, 2018
• Est. completion date: February 12, 2019

Study information

• Verified date: February 2019
• Source: University of Zurich
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial 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.

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 30
• Est. completion date: February 12, 2019
• Est. primary completion date: October 26, 2018
• Accepts healthy volunteers: No
• Gender: All
• Age group: 18 Years to 65 Years

Eligibility

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

Related Conditions & MeSH terms

• Hypoxia
• Hypoxia, Brain

Intervention

Drug:
• Oxycarbon (5% CO2+ 95% O2)
Oxycarbon will be administered by mechanical ventilation

Locations

Country	Name	City	State
Switzerland	University Hospital Zurich	Zurich

Sponsors (1)

Lead Sponsor	Collaborator
University of Zurich

Country where clinical trial is conducted

Switzerland, 

References & Publications (6)

Ainslie PN, Poulin MJ. Ventilatory, cerebrovascular, and cardiovascular interactions in acute hypoxia: regulation by carbon dioxide. J Appl Physiol (1985). 2004 Jul;97(1):149-59. Epub 2004 Mar 5. — View Citation

Brzecka A. Role of hypercapnia in brain oxygenation in sleep-disordered breathing. Acta Neurobiol Exp (Wars). 2007;67(2):197-206. Review. — View Citation

Hannay DR, Maddox EJ. Symptom prevalence and referral behaviour in Glasgow. Soc Sci Med. 1976 Mar-Apr;10(3-4):185-9. — View Citation

Karl AA, McMillan GR, Ward SL, Kissen AT, Souder ME. Effects of increased ambient CO2 on brain tissue oxygenation and performance in the hypoxic rhesus. Aviat Space Environ Med. 1978 Aug;49(8):984-9. — View Citation

Kety SS, Schmidt CF. THE EFFECTS OF ALTERED ARTERIAL TENSIONS OF CARBON DIOXIDE AND OXYGEN ON CEREBRAL BLOOD FLOW AND CEREBRAL OXYGEN CONSUMPTION OF NORMAL YOUNG MEN. J Clin Invest. 1948 Jul;27(4):484-92. — View Citation

Kronenberg RS, Drage CW. Attenuation of the ventilatory and heart rate responses to hypoxia and hypercapnia with aging in normal men. J Clin Invest. 1973 Aug;52(8):1812-9. — View Citation

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Time to decrease of tissue oxygenation index by 20 %	Parameter will be measured by NIRS	1 Day
Secondary	PaO2 (Oxygen partial pressure)	Parametere will be measured by arterial bloodgas	1 Day
Secondary	SpO2 (oxygen saturation)	Parametere will be measured by arterial bloodgas	1 Day
Secondary	PCO2 ( partial pressure of carbon)	Parametere will be measured by arterial bloodgas	1Day