Effect of obesity and site of surgery on perioperative lung volumes.
BACKGROUND
Although obese patients are thought to be susceptible to postoperative pulmonary complications, there are only limited data on the relationship between obesity and lung volumes after surgery. We studied how surgery and obesity affect lung volumes measured by spirometry.


METHODS
We prospectively studied 161 patients having either breast surgery (Group A, n=80) or lower abdominal laparotomy (Group B, n=81). Premedication and general anaesthesia were standardized. Spirometry was measured with the patient supine, in a 30 degrees head-up position. We measured vital capacity (VC), forced vital capacity, peak expiratory flow and forced expiratory volume in 1 s at preoperative assessment (baseline), after premedication (before induction of anaesthesia) and 10-20 min, 1 h and 3 h after extubation.


RESULTS
Baseline spirometric values were all within the normal range. All perioperative values decreased significantly with increasing body mass index (BMI). The greatest reduction of mean VC (expressed as percentage of baseline values) occurred after extubation, and was more marked after laparotomy than after breast surgery (23 (SD 14)% vs 20 (14)%). Considering patients according to BMI (<25, 25-30, >30), VC decreased after surgery by 12 (7)%, 24 (8)% and 40 (10)%, respectively. VC recovered more rapidly in Group A.


CONCLUSIONS
Postoperative reduction in spirometric volumes was related to BMI. Obesity had more effect on VC than the site of surgery.
von Ungern-Sternberg
B S
BS
Department of Anaesthesia, University of Basel/Kantonsspital, CH-4031 Basel, Switzerland. bvonungern@uhbs.ch
Regli
A
A
Schneider
M C
MC
Kunz
F
F
Reber
A
A
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000768:Anesthesia, General; D015992:Body Mass Index; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D007044:Hysterectomy; D008408:Mastectomy; D008875:Middle Aged; D009765:Obesity / Q000150:complications / Q000503:physiopathology*; D010149:Postoperative Pain; D011183:Postoperative Complications; D011184:Postoperative Period; D011446:Prospective Studies; D012131:Respiratory Insufficiency / Q000209:etiology; D013147:Spirometry; D014797:Vital Capacity