[Perioperative Management of Restrictive Pulmonary Disease]

Restrictive ventilatory dysfunction is defined as a reduced vital capacity compared with the predicted value. The causes of such respiratory dysfunction include reduced muscle power, increased lung elastic- ity, and increased chest wall elasticity. During intraoperative mechanical ventilation, the patient's tidal volume is reduced to prevent increases in airway pressure. Due to the associated reduction in the ventilatory time constant, the patient's respiratory frequency can be easily increased to compensate for the reduction in their tidal volume, resulting in the maintenance of an adequate arterial partial pressure of carbon dioxide. As the resultant rise in intrathoracic pressure compresses the pulmonary vessels, pulmonary vascular resistance increases, and this can induce right ventricle failure and/or left ventricle collapse. Increased intrathoracic pressure also leads to reductions in venous return and cardiac output, especially in patients with increased chest wall elasticity. As fatigue and weakness of the ventilatory muscles can cause respiratory failure in such patients ; muscle relaxant should be reversed ; motor nerve blockade must be avoided; and pain management must be con- ducted carefully after surgery.