The impact of preoperative body mass index on respiratory complications after pneumonectomy for non-small-cell lung cancer. Results from a series of 154 consecutive standard pneumonectomies

OBJECTIVE: Although it may seem intuitive that obesity is an additional risk factor for surgical patients, few studies have correlated this condition with lung cancer resection. The only data currently available suggest that obesity does not increase the rate of complications after anatomic resection for non-small-cell lung cancer (NSCLC). METHODS: We enrolled 154 consecutive patients undergoing standard pneumonectomy for NSCLC at the Department of Thoracic Surgery of the European Institute of Oncology from January 2004 to April 2008. To determine the influence of preoperative body mass index (BMI) on postoperative complications, patients were classified into two groups: (1) BMI ≥ 25 kg m⁻²; n = 93 (60.4%); and (2) BMI < 25 kg m⁻²; n = 61 (39.6%). Data on sex, age, cigarette smoking, preoperative albumin, total proteins and creatinine values, forced expiratory volume in 1s percentage (FEV1%), diffusion lung capacity for carbon monoxide/alveolar volume percentage (DLCO/AV%) and histology and pathological stage were collected. Information on total postoperative complications, 30-day mortality rate, specific pulmonary and cardiac complications, intensive care unit (ICU) admission and hospital stay was collected and analysed for the BMI group. RESULTS: Among the 154 operated patients, 30 (19.5%) were women with a mean age of 63.4 years (range: 36-82). As many as 136 (88.3%) patients were smokers or former smokers; 80 patients (51.9%) received presurgical treatment. A total of 64 (41.6%) right pneumonectomy procedures were performed. Mean ± SD for preoperative variables were FEV1%: 83.5 ± 19.2, DLCO/AV: 85.4% ± 20.3, albumin: 4.07 ± 0.44 g dl(-1), total proteins: 7.23 ± 0.59 g dl⁻¹, creatinine: 0.81 ± 0.23 mg dl⁻¹. Ten patients died within the first 30 days (30-day mortality: 6.5%). The male sex was significantly more prevalent in the high BMI group (p=0.039). The preoperative mean creatinine value was significantly higher in the high BMI group (0.86 mg dl(-1) vs 0.75 mg dl⁻¹, p=0.002) and preoperative DLCO/AV values were better in the high BMI group than in the BMI group < 25 kg m⁻² (79.9 vs 88.8, p = 0.009). The high BMI group had a higher incidence of respiratory complications (21.5% vs 4.9% p = 0.005, odds ratio (OR) = 5.3, 95% confidence interval (CI): 1.5, 18.7). No significant differences were observed between the two groups regarding ICU admission, hospital stay, 30-day mortality and total and specific cardiac complications. CONCLUSIONS: The risk of respiratory complications in patients with BMI higher than 25 kg m⁻² undergoing pneumonectomy for lung cancer is 5.3 times higher than that of patients with BMI < 25 kg m⁻². Thoracic surgeons and anaesthesiologists should be aware of this information before planning elective pneumonectomy in overweight and especially in obese patients.