Spirometry in surgery for anterior mediastinal masses

Study objectives: To identify the impact of upright and supine spirometry (USS) on the choice of anesthesia and outcomes in patients undergoing surgery for anterior mediastinal masses (AMMs). Design: Retrospective cohort study. Setting: A referral, tertiary-care, military medical center. Patients: We reviewed the records of all patients who underwent surgery for AMMs between June 1994 and December 2000 at Walter Reed Army Medical Center. Patients aged greater than or equal to 18 years who had "anterior mediastinal mass" listed as the preoperative diagnosis, which had been confirmed by, a preoperative CT scan, and who had available preoperative spirometry data were included in our analysis. In cases in which surgery was performed more than once on the same individual, only data from the first operation were evaluated. Measurements: Patient demographics, the results of pulmonary function testing, perioperative complications, type of anesthesia, type of surgery, and pathology were used in the evaluation. Results: Thirty-seven patients (median age, 31 years; age range, 19 to 86 years) were included in the final analysis. There were 24 men and 13 women in this group. The mean (+/- SD) seated FVC and FEV1 values for the group were 4.02 +/- 0.75 L (90.7 +/- 13.3% predicted) and 3.22 +/- 0.56 L 89.6 +/- 14.2% predicted. Twelve patients (32.4%) had USS ordered, and 10 patients (27.0%) had USS performed. USS was ordered significantly more frequently in younger and symptomatic patients (p = 0.022 and p = 0.005, respectively). Spirometry suggestive of possible upper airway obstruction was found in four patients. However, general anesthesia was used in all four patients without complications. Only two patients suffered perioperative complications. One of these patients had normal USS values but underwent surgery under local anesthesia nonetheless. Conclusions: The recommendation to perform USS prior to surgery on AMMs is based on anecdotal data. Our study found that the incidence of perioperative complications in surgery for AMMs is low. We also found that USS is not ordered in all patients preoperatively and that the results do not always alter the anesthetic technique when abnormal. One patient who experienced a perioperative complication had normal USS values. Larger studies are necessary to further evaluate the utility of USS in surgery for AMMs.