Читать книгу Manual of Equine Anesthesia and Analgesia - Группа авторов - Страница 210

 In the normal horse, the V/Q ratio is close to 1.0.

 This normal V/Q relationship may be altered by the distribution of ventilation, perfusion and/or a change in their relative distribution.When a lung unit has low or no ventilation relative to perfusion, blood leaving the unit will have lower O2 content than units with optimal V/Q relationships.Figure 4.4 Blood entering the pulmonary capillaries associated with non‐ventilated alveoli is termed “shunt,” and represents a V/Q ratio of 0. Alveoli that are ventilated but not perfused are termed “deadspace” and represents a V/Q ratio of infinity. Alveoli that are equally perfused and ventilated represent a V/Q ratio of 1.

  If the V/Q relationship is 0, the blood leaving this unit will have O2 content similar to pulmonary artery blood.In this situation, the blood leaving this unit is referred to as an intrapulmonary shunt and is most commonly a result of atelectasis, partial or complete airway obstruction.

 The other extreme, a V/Q ratio of infinity, is dead space ventilation.