Preoperative Gender Differences in Pulmonary Gas Exchange in Morbidly Obese Subjects

• Published in: Obesity surgery 2008-12, Vol.18 (12), p.1587-1598
• Main Authors: Zavorsky, Gerald S., Christou, Nicolas V., Kim, Do Jun, Carli, Franco, Mayo, Nancy E.
• Format: Article
• Language: English
• Subjects: Adult; Anesthesia; Body Composition; Body mass index; Exercise; Exercise - physiology; Female; Gastrointestinal surgery; Gender differences; High density lipoprotein; Hospitals; Humans; Hyperventilation; Male; Medicine; Medicine & Public Health; Middle Aged; Obesity; Obesity, Morbid - physiopathology; Obesity, Morbid - surgery; Oxygen Consumption; Physical fitness; Pulmonary Diffusing Capacity; Pulmonary Gas Exchange - physiology; Research Article; Sex Factors; Surgery; Waist-Hip Ratio; Weight control; Women; Young Adult
• ISSN: 0960-8923; 1708-0428
• DOI: 10.1007/s11695-008-9527-6

Background Morbidly obese men may have poorer pulmonary gas exchange compared to morbidly obese women (see Zavorsky et al., Chest 131:362–367, 2007 ). The purpose was to compare pulmonary gas exchange in morbidly obese men and women at rest and throughout exercise. Methods Twenty-five women (age = 38 ± 10 years, 164 ± 7 cm, body mass index or BMI = 51 ± 7 kg/m 2 , peak oxygen consumption or O 2peak  = 2.0 ± 0.4 l/min) and 17 men (age = 43 ± 9 years, 178 ± 7 cm, BMI = 50 ± 10 kg/m 2 , O 2peak  = 2.6 ± 0.8 l/min) were recruited to perform a graded exercise test on a cycle ergometer with temperature-corrected arterial blood-gas samples taken at rest and every minute of exercise, including peak exercise. Results At rest, women were 98% predicted for pulmonary diffusion compared to 88% predicted in men. At rest, women had better pulmonary gas exchange compared to the men which was related to women having a lower waist-to-hip ratio (WHR; p  35 mmHg), and both were not different between genders. Conclusion At rest, morbidly obese men have poorer pulmonary gas exchange and pulmonary diffusion compared to morbidly obese women. The better gas exchange in women is related to the lower WHR in the women. During exercise, few subjects showed disturbances in pulmonary gas exchange despite demonstrating poor compensatory hyperventilation at peak exercise.