THE EFFECTS OF ANAESTHESIA ON RESPIRATORY FUNCTION ANAESTHESIA TUTORIAL OF THE WEEK 205

Abstract

Understanding the multiple effects that general anaesthesia has on the respiratory system is essential if gas exchange and ventilation are to be maintained.
The loss of a patent airway, hypoventilation and apnoea cause hypercapnia, which has many undesirable effects. Anaesthetists must anticipate and prepare for these effects. A patent airway and ventilation must be maintained.
Gas exchange is impaired by airway obstruction, V/Q mismatch, shunt and the reversal of HPV, any of which results in hypoxia. The anaesthetist must strive to maximise the FRC and it’s oxygen content. Mechanical ventilation may be required which can be improved with recruitment, PEEP and lung protective strategies. However, remember that mechanical ventilation can cause damage to the lung tissue.These problems extend into the postoperative period. Patients must have adequate postoperative analgesia, and some may require supplemental oxygen.