Bi-PAP vs Sham Bi-PAP on Pulmonary Function in Morbidly Obese Patients After Bariatric Surgery

The Effect of Bi-PAP at Individualized Pressures on the Postoperative Pulmonary Recovery of Morbidly Obese Patients (MOP) Undergoing Open Bariatric Surgery (OBS) and Possible Placebo Device-related Effects (Sham-Bi-PAP)

The effect of biphasic positive airway pressure (Bi-PAP) at individualized pressures on the postoperative pulmonary recovery of morbidly obese patients (MOP) undergoing open bariatric surgery (OBS) and possible placebo device-related effects (sham-Bi-PAP) were investigated.

In the present study the effect of Bi-PAP on the postoperative respiratory function and related complications of MOP undergoing OBS through a randomized sham-controlled design was investigated. Bi-PAP was applied at individualized pressures in order to optimize respiratory support and sham Bi-PAP was also used in order to neutralize possible placebo device related effect and researcher related bias.

The investigators hypothesized that the use of Bi-PAP at individualized pressures in MOP undergoing OBS, ameliorates postoperative respiratory function as well as diminishes related pulmonary complications, postoperative pain and duration of hospitalization. Primary endpoints were the difference in pre- and postoperative measurements of certain pulmonary function parameters (forced expiratory volume at one second (FEV1), forced vital capacity (FVC), peak expiratory flow rate (PEFR) and oxygen saturation by pulse oximetry (SpO2) and the incidence of certain pulmonary complications postoperatively (hypoxemia, atelectasis, lower respiratory tract infections). Secondary endpoints were postoperative pain and days of hospitalization.

Inclusion Criteria:

• All patients have been Morbidly Obese (BMI> 40kg/m2) for at least 10 years
• All patients had unsuccessfully tried to lose weight by other non-invasive means.
• All patients enrolled were continuous positive airway pressure (CPAP) and Bi-PAP naïve and had no knowledge about the Bi-PAP apparatus prior to enrollment
• All patients underwent OBS (gastroplasty by Mason or gastric bypass) by the same operating team
• All patients were treated with the same standard anesthetic protocol

Exclusion Criteria:

• Cardiovascular and pulmonary disease not related to obesity status
• Chronic renal disease
• Patients who were initially enrolled but did not use the allocated device (Bi-PAP or Sham Bi-PAP) for at least 12 h daily were also excluded at a later point.