SLC9C1 and Acidosis: The available evidence would suggest that this pCO2 may be sufficient to generate a small respiratory acidosis (Esbaugh et al. 2012; Esbaugh et al., 2016; Ern and Esbaugh, 2018), yet to impact Pcrit it would need to overwhelm the β-adrenergic sodium-proton exchanger (NHE) in the red blood cell (reviewed by Esbaugh, 2018).