Background: The objective of this study was to evaluate the relationship between oxygen partial pressure (pO(2)), awake oxymetric saturation (SpO(2)), body mass index (BMI), and percentage of excess weight loss (EWL) in extremely severe obesity (BMI >50 kg m(-2)) and hypoxemia, before and after laparoscopic Roux-en-Y gastric bypass.
Patients and methods: A group of 11 obese patients aged 41.2 + or - 10.2 years (4 men, 7 women, median BMI=52.3 kg/m(2), range 50.2-57.1) were prospectively enrolled in the study. BMI, arterial blood gas measurements, and spirometry were obtained before and after (6 and 12 months) surgery.
Results: The main preoperative parameters were SpO(2)=88.3 + or - 3.9%, predicted forced vital capacity (FVC)=84.5 + or - 8.3%, predicted forced expiratory volume exhaled in one second (FEV1)=79.9+/-10.1%. No relationship (p>0.01) was found between BMI, SpO(2), and FEV1. A significant correlation between SpO(2) and both paO(2) (R=0.74, p=0.009) and EWL (R=-0.75, p=0.008) was found. Three, 6, and 12 months after surgery EWL was 18.9%, 26.4%, and 39.6% (p<0.001), respectively. At one-year follow-up SpO(2), FVC, and FEV1 were 96.2 + or - 3.2% (p<0.001), 112.3 + or - 9.9% (p<0.001), and 101.6 + or - 18.8% (p=0.003), respectively.
Conclusion: In patients with extremely severe obesity, bariatric surgery may improve significantly both SpO(2) and spirometric parameters, and EWL represents the factor that impacted the results.