title: Compensation of pulmonary function after upper lobectomy versus lower lobectomy.
abstract: OBJECTIVE
  Major lung resection may induce expansion of the remaining lung, accompanied by some gain in the function of this lung; however, the impact of the site of resection on this compensatory response remains unclear.
  
  
  METHODS
  We measured computed tomography-based functional lung volume, representing normal lung attenuation (-600 to -910 Hounsfield units), and spirometry-based lung function (forced expiratory volume in 1 second) preoperatively and 6 months postoperatively in patients with lung cancer and compared them between patients undergoing upper lobectomy (n = 34) and patients undergoing lower lobectomy (n = 26).
  
  
  RESULTS
  We removed 17% ± 4% of the functional lung volume by upper lobectomy and 27% ± 5% by lower lobectomy (P < .001). Postoperatively, the residual lung expanded by various degrees, accompanied by a proportionate gain in the residual lung function (R = 0.6, P < .001). This anatomic and functional compensation of the residual lung was more remarkable after lower lobectomy than after upper lobectomy (P <.05). Consequently, the percentage loss of the functional lung volume after upper lobectomy (10% ± 10%) did not differ significantly from that after lower lobectomy (9% ± 12%, P = .6). Likewise, the percentage loss of lung function after upper lobectomy (12% ± 16%) did not differ significantly from that after lower lobectomy (14% ± 17%, P = .6).
  
  
  CONCLUSIONS
  Although the lower lobectomy implies greater resection than the upper lobectomy, lung function after lower lobectomy was not inferior to that after upper lobectomy because the compensatory response appeared more robust after lower lobectomy.
authors.affiliation: Department of Surgery and Clinical Science, Division of Chest Surgery, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube, Yamaguchi, 755-8505, Japan. kaueda@c-able.ne.jp
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Ueda
authors.forename: Toshiki
authors.initials: T
authors.lastname: Tanaka
authors.forename: Masataro
authors.initials: M
authors.lastname: Hayashi
authors.forename: Tao-Sheng
authors.initials: TS
authors.lastname: Li
authors.forename: Takehiro
authors.initials: T
authors.lastname: Kaneoka
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Tanaka
authors.forename: Kimikazu
authors.initials: K
authors.lastname: Hamano
mesh_terms: D000222:Adaptation, Physiological; D000368:Aged; D016009:Chi-Square Distribution; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D007564:Japan; D016014:Linear Models; D008168:Lung / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D008175:Lung Neoplasms / Q000601:surgery*; D008176:Lung Volume Measurements; D008297:Male; D008875:Middle Aged; D011013:Pneumonectomy / Q000009:adverse effects / Q000379:methods*; D020127:Recovery of Function; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013147:Spirometry; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014797:Vital Capacity