Relationship between Body Mass Index, Age and Hypoxemia in Patients with Extremely Severe Obesity Undergoing Bariatric Surgery

Background: Morbid obesity is frequently accompanied by serious co-morbidity, enclosed obstructive sleep apnea and hypoventilation syndrome, and thus many morbidly obese patients require surgical interventions. The aim of this study was to evaluate the relationship between arterial oxygen (pO2) and carbon dioxide (pCO2) partial pressure, age, loss of excess weight, and body mass index (BMI) in obese patients scheduled to undergo bariatric surgery. Patients and Methods: A group of 11 patients (4 men, 7 women, median age 38 years, range 23-58 years) with extremely severe obesity (BMI>50 kg/m2) underwent laparoscopic Roux-en-Y gastric bypass. Preoperatively, BMI, pO2, and pCO2 were 52.7\ub12.4 kg/m2, and 70.9\ub15.3 and 43.1\ub16.5 mmHg, respectively. Hypoxemia (pO2<75 mmHg) was present in all patients, but no relationship between BMI and age (R=\u20130.24, p=0.44) or between BMI and pO2 (R=0.09, p=0.77) was found. Results: As expected, there was a significant correlation between age and both pO2 (R=\u20130.58, p=0.04) and pCO2 (R=0.85, p=0.0004), while no relationship between BMI and age (R=\u20130.24, p=0.44), nor between BMI and pO2 (R=0.09, p=0.77) was found. Finally, there was a significant correlation between pO2 and loss of excess weight (R=\u20130.69, p=0.02). No intra- or postoperative complications were observed, and 12 months after surgery BMI decreased to 32.5\ub12.7 kg/m2 (p<0.001) and pCO2 to 37.9\ub15.3 mmHg (p=0.05), while pO2 reached 85.8\ub16.8 (p