The results of surgery under general anesthesia in patients with lung cancer.

Purpose: There are few reports of surgical complications for underweight patients. This study evaluated the complications associated with lung cancer surgery and anesthesia in underweight patients in a comparison with obese ones.

Methods: A single-center retrospective evaluation of perioperative complications was conducted in 756 patients who underwent thoracic surgery under general anesthesia between 1996 and 2006. The body mass index showed that 39 were extremely underweight (<17.2 kg/m(2)), 45 were underweight (17.2-18.4 kg/m(2)), 513 were normal (18.5-24.9 kg/m(2)), and 159 were obese (>24.9 kg/m(2)).

Results: Extremely underweight patients had the most preoperative thoracic disease such as emphysema, whereas obese patients had the most preoperative cardiovascular disease such as hypertension. The postresection-predicted pulmonary function showed no difference among the four groups. Extremely underweight patients had an increased incidence of intraoperative hypotension and arrhythmia in comparison to underweight patients. On the other hand, obese patients had the majority of intraoperative thoracic complications such as hypoxia. Extremely underweight patients had more postoperative thoracic complications, especially pneumonia and pulmonary air leakage, than other patients.

Conclusions: Extremely underweight patients as well as obese patients had a high risk of perioperative complications, especially postoperative thoracic complications. Extremely underweight patients should therefore be carefully observed with regard to respiratory management.