Chronic obstructive pulmonary disease (COPD) includes emphysema, peripheral airways disease, and chronic bronchitis. Any individual patient may have one or all of these conditions, but the dominant clinical feature is impairment of expiratory airflow.

1. Some moderate and severe COPD patients have an elevated PaCO₂ at rest (Paco₂ rises in these patients when supplemental Fio₂ is administered). Supplemental oxygen must be administered postoperatively to prevent the hypoxemia associated with the unavoidable fall in functional residual capacity. The attendant rise in Paco₂ should be anticipated and monitored.

2. To identify these patients preoperatively, all moderate or severe COPD patients need an arterial blood gas analysis (important to know the patient’s baseline preoperative Paco₂ to guide weaning if mechanical ventilation becomes necessary in the postoperative period).

3. COPD patients desaturate more frequently and severely than normal patients during sleep (due to the rapid/shallow breathing pattern that occurs in all patients during REM sleep).

4. Right ventricular dysfunction occurs in up to 50% of moderate to severe COPD patients.

   1. The dysfunctional right ventricle is poorly tolerant to sudden increases in afterload such as the change from spontaneous to controlled ventilation.

   2. Chronic recurrent hypoxemia is the cause of the right ventricle dysfunction and the subsequent progression to cor pulmonale. COPD patients who have resting Pao₂ less than 55 mm Hg should receive supplemental home oxygen.

5. Many patients with moderate or severe COPD will develop cystic air spaces in the lung parenchyma known as bullae.

   1. Positive pressure ventilation can be used safely in patients with bullae, provided the airway pressures are kept low.

   2. Due to the lower solubility of nitrogen in plasma compared to nitrous oxide, when a patient is converted from breathing air to breathing a mixture containing nitrous oxide during anesthesia, the nitrous oxide will diffuse into a bulla faster than the nitrogen can be absorbed, and the bulla will increase in size with the attendant risk of rupture.

6. Patients with severe COPD often breathe in a pattern that interrupts expiration before the alveolar pressure has fallen to atmospheric pressure (leads to an elevation of the end-expiratory lung volume above the FRC and has been termed auto-PEEP or intrinsic-PEEP).

Restrictive lung diseases are often part of a multisystemic disease process such as connective tissue disorders.

1. Patients with mild to moderate restrictive lung disease are, in general, less of a problem to manage intraoperatively (compared to COPD) and more of a problem postoperatively.

2. Due to the decrease in FRC in restrictive disease, these patients tend to develop an increased shunt during anesthesia and postoperatively (restoration of the FRC postoperatively is important).