Ventilatory response to hypercapnia

Beginning at a normal ventilation of 5 to 8 L/min and a PaCO₂ equal to 40 mmHg, ventilation increases linearly as PCO₂ rises. In normal individuals there is a range of responsiveness between 2 and 5 L/min/mmHg rise in PCO₂. Hypoxemia heightens the response and shifts the curve up and to the left.