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Higher inspired oxygen (
  
    
      
        
          
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    {\displaystyle {P_{i_{O_{2}}}}}
  ) at 4 atm (400 kPa) accounted for not more than 25% of the elevation in end tidal CO2 (ETCO2) above values found at the same work rate when breathing air just below the surface.
Some children get tracheomalacia because of other health issues. Symptoms can be mild to severe.Symptoms inside the lung include noisy breathing that may get better when you change your babys position or while he or she is asleep. Breathing problems that get worse during coughing, crying, feeding or colds. High-pitched sound during breathing (stridor). High-pitched cough. Rattling noise or wheezing with breathing. Diagnosis
There is no standardized, defined set of diagnostic criteria for the diagnosis of tracheomalacia, mainly due to the nonspecific symptoms associated with it. Current diagnostic approaches include pulmonary function testing which shows a characteristic reduction in peak expiratory flow (PEF), physical examination, and imaging such as computed tomography (CT) or magnetic resonance imaging (MRI), fiberoptic bronchoscopy (FB) is considered the best diagnostic method because an inserted camera down the throat shows a direct view of the airways and lungs, detecting changes in the size or appearance of the tracheas lumen and mucosa and any signs of inflammation, fistulas, or external compressions to precisely determine the location and severity of the malacia. Cross-sectional radiological images are important in detecting mediastinal structures involved in TM prior to surgery. Tracheography/Bronchography is no longer a preferred diagnostic method. Bronchography provides an accurate measurement of the airway lumen with a dynamic and morphological evaluation of the tracheobronchial tree. However, this requires the injection of contrast material within the narrowed airway. Risks include allergic reaction, airway plugging, or complete airway obstruction.