Newer pulmonary function instruments make measurement of small airway function possible as a routine, inexpensive part of preoperative preparation of patients with obstructive lung disease. Patients with early stages of chronic obstructive lung disease have maldistribution of ventilation and perfusion producing an increased A-a oxygen gradient. If the disease is at a reversible stage, early diagnosis and treatment should be helpful in preventing postoperative complications. Five volunteer heavy smokers stopped smoking for one week without any improvement in small airway function. A longer period of abstinence and other therapeutic modalities for these patients is needed prior to surgery to reduce the postoperative impact of this pathology.