EDKP 485 Lecture Notes - Lecture 4: 20 Y.O., Acidosis, Hyperventilation

• School: McGill University
• Department: Kinesiology and Physical Ed
• Course: EDKP 485
• Professor: Dennis Jensen

Document Summary

Physiological determinants of ventilatory demand: paco2 = set point of co2 for dead space = to have enough air participating in gas exchange despite dead space. B) paco2 = set point need to ventilate more to expire more co2 to restrain acidosis. Typically paco2 of 40 mmhg [38-42] - usually independent of age/sex. If paco2 of 30 mmhg hyper-ventilation. If paco2 of 50 mmhg hypo-ventilation. Examples - high ventilatory equivalent can reflect a) or b) Graph = lower (cid:1779) (cid:1777)(cid:1789) better & higher (cid:1779) (cid:1777)(cid:1789) worse *inverse. Ex: (cid:1779) (cid:1777)(cid:1789) = 20 indicate that 20% of breathing is wasted so 80% = efficient: (cid:1778) = physiological dead space ventilation at constant paco2 of 40 mmhg. Ventilatory equivalent (cid:1779) (cid:1777)(cid:1789) = 30 at so (cid:1778) = 0. 2. Ventilatory equivalent (cid:1779) (cid:1777)(cid:1789) = 50 at so (cid:1778) = 0. 5. Results = increased dead space ventilation so ventilation inefficient. Either poorly ventilated or perfused lungs: paco2 = metabolic acidosis at constant (cid:1778)