Work Step by Step
Emphysema & Acid - Base balance - Emphysema leads to hyperventilation - CO2 retention - PaCO2 more than 44 mmHg. - it causes the following : 1- Defective Ventilation : creation of a pathological dead space, which impaires normal mixing of gases & diffusion to capillaries. 2- Diminished Perfusion from : a- damage of the vessels or their vasoconstriction ( from Anoxia ). b- disturbed Ventilation / Perfusion ratio in one area. 3- additional effects : Air trapping collapse & closure of bronchioles already narrowed during expiration ( intrapleural pressure rises ) causes air trapping in acini with further interfere with mixing of gases. Congestive Heart Failure & Acid-Base Balance - Congestive Heart Failure ( left side failure ) leads to arise in the pressure of the left atrium- which causes back pressure in the pulmonary veins & pulmonary congestion. - pulmonary congestion - increased pulmonary pressure - exudation occurs in Alveoli - Pulmonary edema -obstruction of air passages - lack of removal of CO2 - increased blood H2CO3 - Respiratory Acidosis.