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

Evangelismos Hospital48 enrolled

Overview

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.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Enrollment

Conditions

Atelectasis

Interventions

Bi-PAPDEVICE

The Bi-PAP system combines inspiratory support-IPAP (inspiratory positive airway pressure) with expiratory support-EPAP (expiratory positive airway pressure) and has been used, with good results, in a number of different clinical conditions such as COPD, respiratory failure due to neuromuscular disease, cardiogenic pulmonary edema and immediately post-operatively with pro-phylactic purpose.

Sham Bi-PAPDEVICE

Sham Bi-PAP was created by introducing a "hole" at the connection of the mask with the spiral tube of the conventional Bi-PAP system. By doing so, the applied pressure by sham Bi-PAP was constant and equal to 2 cm H2O.

Eligibility

Sex: ALL

Medical Language ↔ Plain English

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.

Outcomes

Primary Outcomes

Forced Expiratory Volume at One Second (FEV1) Difference

difference in FEV1 value measured by spirometry pre- and post-operatively

Time frame: 24 h before surgery and at 24, 48 and 72 h post-operatively

Forced Vital Capacity (FVC) Difference

difference in FVC value measured by spirometry pre- and post-operatively

Time frame: 24 h before surgery and at 24, 48 and 72 hours post-operatively

Peak Expiratory Flow Rate (PEFR) Difference

difference in PEFR value measured by spirometry pre- and post-operatively

Time frame: 24 h before surgery and at 24, 48 and 72 hours post-operatively

SpO2 Difference

difference in SpO2 value measured by spirometry pre- and post-operatively

Time frame: 24 h before surgery and at 24, 48 and 72 hours post-operatively

Number of Participants With Hypoxemia

occurrence of hypoxemia, considered as SpO2\<90%, post-operatively

Time frame: At 24, 48 and 72 hours post-operatively

Number of Participants With Atelectasis

occurrence of atelectasis as defined by chest X-ray (CXR) post-operatively with CXR before surgery as baseline

Time frame: At 24, 48 and 72 hours post-operatively

Secondary Outcomes

Post-operative Pain

Intensity of pain was assessed post-operatively by Numerical Rating Scale (NRS) (0-10, 0=no pain, 10=worst pain imaginable)

Time frame: right before spirometry, at 24, 48 and 72 h post-operatively

Days of Hospitalization

duration of hospitalization, calculated by discharge date minus admission date

Time frame: From day of admission to day of discharge from the hospital