This is a Phase I, open-label, single center trial to evaluate the feasibility and safety of low concentration CO2 gas mixture (5% CO2 + 95% air) inhalation in asphyxiated, cooled, mechanically ventilated newborns at risk of hypocapnia with The hypothesis is that hypocapnia, which is driven by hyperventilation in the presence of metabolic acidosis, is deleterious to the injured brain and can be safely avoided with low concentration CO2 inhalation.
Specific aims: 1. To test the feasibility of low concentration inhalative CO2 gas mixture (5% CO2 + 95% air) administration to achieve a desired range of pCO2 of 40-60 mmHg in asphyxiated, cooled, mechanically ventilated newborns at risk of hypocapnia with moderate to severe hypoxic-ischemic encephalopathy. 2. To test the safety of CO2 gas mixture (5% CO2 + 95% air) inhalation in asphyxiated, cooled, mechanically ventilated newborns at risk of hypocapnia with moderate to severe hypoxic-ischemic encephalopathy. Term infants (≥ 36 weeks of gestation) will have to be at risk of hypocapnia to be eligible, as defined by a temperature corrected pCO2 ≤ 40 mmHg in blood gas analysis, at any time within six hours of life. The gas mixture will be administered through patient circuits in conventional ventilators. Administered CO2 level will be closely monitored at the inhalation circuit (constant 5% = 36 mmHg). Blood gas samples will be taken hourly to ensure targeted and tolerable pCO2 levels.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
10
5% CO2 (36 mmHg) and 95% air gas mixture inhalation, for a maximum of 12 hours or until metabolic acidosis recovery occurs as measured by BE \> -5 mmol/L in arterial blood gas samples
Semmelweis University, 1st Department of Pediatrics
Budapest, Hungary
Percentage of time spent in the desired pCO2 range of 40-60 mmHg (temp. corrected) during CO2 inhalation.
Time frame: 3 days
Number of seizures, either detected clinically or by amplitude integrated EEG monitoring
Time frame: Within one week
Time until the end point of metabolic acidosis (BE > -5 mmol/L)
Time frame: During CO2 inhalation (max. 12 hours)
Time until the end point of acidosis (pH > 7.25)
Time frame: During therapeutic hypothermia (max. 72 hours)
Severe hypotension (mean arterial pressure less than 25 mmHg), despite full inotrope support and volume replacement.
Time frame: During therapeutic hypothermia (max. 72 hours)
Intracranial haemorrhage detected by MRI
Time frame: Within seven days
Reduction in Lac/NAA ratio on magnetic resonance spectroscopy
Time frame: Within seven days
Preserved fractional anisotropy measured on diffusion weighted MRI
Time frame: Within seven days
Death
Time frame: Within one month
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