Atelectasis, Chronic Obstructive Pulmonary Disease (COPD), Hypoxemia, Hypoxemic Respiratory Failure, Morbid Obesity, Pulmonary Disease, Pulmonary Infection
Conditions
Keywords
Bi-PAP, BiPAP, morbid obesity, anesthesia, bariatric surgery, sham Bi-PAP, sham BiPAP, postoperative complications
Brief summary
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.
Detailed description
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.
Interventions
DEVICEBi-PAP
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.
DEVICESham Bi-PAP
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.
Sponsors
Elpis General Hospital
Sotiria General Hospital
Evgenidion Hospital
Evangelismos Hospital
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE
Intervention model description
Patients were assigned into the following two study groups postoperatively: 1. Sham Bi-PAP (control group) group in which sham Bi-PAP was applied through nasal mask for 3 days postoperatively. 2. Bi-PAP group in which Bi-PAP through nasal mask, at individualized IPAP/EPAP pressures, was applied for 3 days postoperatively. 1 patient was initially enrolled in the protocol but was excluded from the participant flow design because of recent onset of cardiovascular disease (CAD).
Eligibility
Sex/Gender
ALL
Healthy volunteers
No
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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Number of Participants With Atelectasis | At 24, 48 and 72 hours post-operatively | occurrence of atelectasis as defined by chest X-ray (CXR) post-operatively with CXR before surgery as baseline |
| SpO2 Difference | 24 h before surgery and at 24, 48 and 72 hours post-operatively | difference in SpO2 value measured by spirometry pre- and post-operatively |
| Number of Participants With Hypoxemia | At 24, 48 and 72 hours post-operatively | occurrence of hypoxemia, considered as SpO2\<90%, post-operatively |
| Forced Expiratory Volume at One Second (FEV1) Difference | 24 h before surgery and at 24, 48 and 72 h post-operatively | difference in FEV1 value measured by spirometry pre- and post-operatively |
| Forced Vital Capacity (FVC) Difference | 24 h before surgery and at 24, 48 and 72 hours post-operatively | difference in FVC value measured by spirometry pre- and post-operatively |
| Peak Expiratory Flow Rate (PEFR) Difference | 24 h before surgery and at 24, 48 and 72 hours post-operatively | difference in PEFR value measured by spirometry pre- and post-operatively |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Days of Hospitalization | From day of admission to day of discharge from the hospital | duration of hospitalization, calculated by discharge date minus admission date |
| Post-operative Pain | right before spirometry, at 24, 48 and 72 h post-operatively | Intensity of pain was assessed post-operatively by Numerical Rating Scale (NRS) (0-10, 0=no pain, 10=worst pain imaginable) |
Participant flow
Recruitment details
Τhis prospective randomized single-blinded study with a control group was conducted in a tertiary urban Greek hospital. Subjects recruitment was performed at the respective departments of obesity surgery where subjects underwent surgery, also belonging to tertiary hospitals.
Pre-assignment details
Exclusion criteria included cardiovascular and pulmonary disease not related to obesity status, and chronic renal disease. From the 48 patients initially enrolled in the study, 1 was excluded from the participant flow because of recent onset of cardiovascular disease. 47 patients were assigned to the study groups.
Participants by arm
| Arm | Count |
|---|---|
| Sham Bi-PAP Sham Bi-PAP was applied through nasal mask for 3 days postoperatively. Sham Bi-PAP was created by introducing a hole at the connection of the mask with the spiral tube of Bi-PAP. With this modality, also used on previous studies, the applied pressure by sham Bi-PAP was constant and equal to 2 cm H2O.
Sham Bi-PAP: 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. | 14 |
| Bi-PAP Bi-PAP through nasal mask, at individualized IPAP/EPAP pressures, was applied for 3 days postoperatively. IPAP and EPAP in the Bi-PAP system were individualized for each patient in accordance with accepted values of SpO2, PaCO2, and patient synchronization and tolerability with the device.Individualized setting of pressures in patient group was applied gradually starting with 12/4 cm H2O (IPAP/EPAP) and up to 18/10 (IPAP/EPAP) with consecutive increases of 2 cm H2O.
Bi-PAP: 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. | 21 |
| Total | 35 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Overall Study | Protocol Violation | 9 | 3 |
Baseline characteristics
| Characteristic | Sham Bi-PAP | Bi-PAP | Total |
|---|---|---|---|
| Age, Continuous | 33 years STANDARD_DEVIATION 8 | 31 years STANDARD_DEVIATION 6 | 31.8 years STANDARD_DEVIATION 6.83 |
| Body mass index-BMI | 52 Kilograms/squared meters STANDARD_DEVIATION 6 | 53 Kilograms/squared meters STANDARD_DEVIATION 8 | 52.6 Kilograms/squared meters STANDARD_DEVIATION 7.19 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 0 Participants | 0 Participants | 0 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 14 Participants | 21 Participants | 35 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants |
| Height | 171 Centimeters STANDARD_DEVIATION 7 | 172 Centimeters STANDARD_DEVIATION 27 | 171.6 Centimeters STANDARD_DEVIATION 21.16 |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Asian | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Black or African American | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) More than one race | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) White | 14 Participants | 21 Participants | 35 Participants |
| Region of Enrollment Greece | 14 participants | 21 participants | 35 participants |
| Sex: Female, Male Female | 8 Participants | 13 Participants | 21 Participants |
| Sex: Female, Male Male | 6 Participants | 8 Participants | 14 Participants |
| Smoking | 7 Participants | 14 Participants | 21 Participants |
| Type of OBS: open gastric bypass | 4 Participants | 6 Participants | 10 Participants |
| Type of open bariatric surgery (OBS): gastroplasty | 11 Participants | 15 Participants | 26 Participants |
| Weight | 151 Kilograms STANDARD_DEVIATION 30 | 157 Kilograms STANDARD_DEVIATION 27 | 154.6 Kilograms STANDARD_DEVIATION 27.96 |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 14 | 0 / 21 |
| other Total, other adverse events | 0 / 14 | 0 / 21 |
| serious Total, serious adverse events | 0 / 14 | 0 / 21 |
Outcome results
Primary
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
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Sham Bi-PAP | Forced Expiratory Volume at One Second (FEV1) Difference | 24h before surgery | 3.1 Litres | Standard Deviation 0.7 |
| Sham Bi-PAP | Forced Expiratory Volume at One Second (FEV1) Difference | 24h post-op | 1.3 Litres | Standard Deviation 0.5 |
| Sham Bi-PAP | Forced Expiratory Volume at One Second (FEV1) Difference | 48h post-op | 1.3 Litres | Standard Deviation 0.4 |
| Sham Bi-PAP | Forced Expiratory Volume at One Second (FEV1) Difference | 72h post-op | 1.4 Litres | Standard Deviation 0.5 |
| Bi-PAP | Forced Expiratory Volume at One Second (FEV1) Difference | 72h post-op | 1.9 Litres | Standard Deviation 0.4 |
| Bi-PAP | Forced Expiratory Volume at One Second (FEV1) Difference | 24h before surgery | 3.1 Litres | Standard Deviation 0.6 |
| Bi-PAP | Forced Expiratory Volume at One Second (FEV1) Difference | 48h post-op | 1.7 Litres | Standard Deviation 0.4 |
| Bi-PAP | Forced Expiratory Volume at One Second (FEV1) Difference | 24h post-op | 1.4 Litres | Standard Deviation 0.3 |
Comparison: 24 h before surgery (pre-operative or baseline values)p-value: 0.88ANOVA
Comparison: 24 h post-operativelyp-value: 0.23ANOVA
Comparison: 48 hours post-operativelyp-value: 0.008ANOVA
Comparison: 72 h post-operativelyp-value: 0.001ANOVA
Primary
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
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Sham Bi-PAP | Forced Vital Capacity (FVC) Difference | 24h before surgery | 3.4 Litres | Standard Deviation 1 |
| Sham Bi-PAP | Forced Vital Capacity (FVC) Difference | 24h post-op | 1.3 Litres | Standard Deviation 0.4 |
| Sham Bi-PAP | Forced Vital Capacity (FVC) Difference | 48h post-op | 1.5 Litres | Standard Deviation 0.5 |
| Sham Bi-PAP | Forced Vital Capacity (FVC) Difference | 72h post-op | 1.9 Litres | Standard Deviation 0.6 |
| Bi-PAP | Forced Vital Capacity (FVC) Difference | 72h post-op | 2.3 Litres | Standard Deviation 0.4 |
| Bi-PAP | Forced Vital Capacity (FVC) Difference | 24h before surgery | 3.5 Litres | Standard Deviation 0.7 |
| Bi-PAP | Forced Vital Capacity (FVC) Difference | 48h post-op | 2.0 Litres | Standard Deviation 0.4 |
| Bi-PAP | Forced Vital Capacity (FVC) Difference | 24h post-op | 1.6 Litres | Standard Deviation 0.4 |
Comparison: 24 h before surgery (pre-operative or baseline values)p-value: 0.75ANOVA
Comparison: 24 h post-operativelyp-value: 0.09ANOVA
Comparison: 48 h post-operativelyp-value: 0.008ANOVA
Comparison: 72 h post-operativelyp-value: 0.013ANOVA
Primary
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
| Arm | Measure | Group | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|---|
| Sham Bi-PAP | Number of Participants With Atelectasis | 24h post-op | 3 Participants |
| Sham Bi-PAP | Number of Participants With Atelectasis | 48h list-op | 3 Participants |
| Sham Bi-PAP | Number of Participants With Atelectasis | 72h post-op | 3 Participants |
| Bi-PAP | Number of Participants With Atelectasis | 24h post-op | 0 Participants |
| Bi-PAP | Number of Participants With Atelectasis | 48h list-op | 0 Participants |
| Bi-PAP | Number of Participants With Atelectasis | 72h post-op | 0 Participants |
Primary
Number of Participants With Hypoxemia
occurrence of hypoxemia, considered as SpO2\<90%, post-operatively
Time frame: At 24, 48 and 72 hours post-operatively
| Arm | Measure | Group | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|---|
| Sham Bi-PAP | Number of Participants With Hypoxemia | 24h post-op | 5 Participants |
| Sham Bi-PAP | Number of Participants With Hypoxemia | 48h post-op | 0 Participants |
| Sham Bi-PAP | Number of Participants With Hypoxemia | 72h post-op | 0 Participants |
| Bi-PAP | Number of Participants With Hypoxemia | 24h post-op | 0 Participants |
| Bi-PAP | Number of Participants With Hypoxemia | 48h post-op | 0 Participants |
| Bi-PAP | Number of Participants With Hypoxemia | 72h post-op | 0 Participants |
Primary
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
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Sham Bi-PAP | Peak Expiratory Flow Rate (PEFR) Difference | 24h before surgery | 376.9 Litres/minute | Standard Deviation 71.7 |
| Sham Bi-PAP | Peak Expiratory Flow Rate (PEFR) Difference | 24h post-op | 146.9 Litres/minute | Standard Deviation 61.4 |
| Sham Bi-PAP | Peak Expiratory Flow Rate (PEFR) Difference | 48h post-op | 166.0 Litres/minute | Standard Deviation 68.1 |
| Sham Bi-PAP | Peak Expiratory Flow Rate (PEFR) Difference | 72h post-op | 190.1 Litres/minute | Standard Deviation 64.2 |
| Bi-PAP | Peak Expiratory Flow Rate (PEFR) Difference | 72h post-op | 247.5 Litres/minute | Standard Deviation 60.5 |
| Bi-PAP | Peak Expiratory Flow Rate (PEFR) Difference | 24h before surgery | 325.3 Litres/minute | Standard Deviation 75.2 |
| Bi-PAP | Peak Expiratory Flow Rate (PEFR) Difference | 48h post-op | 195.7 Litres/minute | Standard Deviation 46 |
| Bi-PAP | Peak Expiratory Flow Rate (PEFR) Difference | 24h post-op | 137.4 Litres/minute | Standard Deviation 30.5 |
Comparison: 24 h before surgery (pre-operative or baseline values)p-value: 0.05ANOVA
Comparison: 24 h post-operativelyp-value: 0.55ANOVA
Comparison: 48h post-operativelyp-value: 0.13ANOVA
Comparison: 72 h post-operativelyp-value: 0.011ANOVA
Primary
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
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Sham Bi-PAP | SpO2 Difference | 24h before surgery | 96.9 percentage of SpO2 | Standard Deviation 0.7 |
| Sham Bi-PAP | SpO2 Difference | 24h post-op | 91.6 percentage of SpO2 | Standard Deviation 3.5 |
| Sham Bi-PAP | SpO2 Difference | 48h post-op | 92.4 percentage of SpO2 | Standard Deviation 3.5 |
| Sham Bi-PAP | SpO2 Difference | 72h post-op | 92.5 percentage of SpO2 | Standard Deviation 3.7 |
| Bi-PAP | SpO2 Difference | 72h post-op | 96.8 percentage of SpO2 | Standard Deviation 1 |
| Bi-PAP | SpO2 Difference | 24h before surgery | 96.9 percentage of SpO2 | Standard Deviation 1.1 |
| Bi-PAP | SpO2 Difference | 48h post-op | 95.2 percentage of SpO2 | Standard Deviation 1.9 |
| Bi-PAP | SpO2 Difference | 24h post-op | 92.6 percentage of SpO2 | Standard Deviation 3.2 |
Comparison: 24 h before surgery (pre-operative or baseline values)p-value: 0.83ANOVA
Comparison: 24 h post-operativelyp-value: 0.37ANOVA
Comparison: 48 h post-operativelyp-value: 0.0035ANOVA
Comparison: 72 h post-operativelyp-value: 0.000015ANOVA
Secondary
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
Population: Overall number of patients analyzed in each group is the sum of participants who underwent gastroplasty and those who underwent open gastric bypass (11+3=14 for the Sham Bi-PAP group and 15+6=21 for the Bi-PAP group).
| Arm | Measure | Group | Value (MEAN) |
|---|---|---|---|
| Sham Bi-PAP | Days of Hospitalization | Type of OBS: gastroplasty | 6 days |
| Sham Bi-PAP | Days of Hospitalization | Type of OBS: open gastric bypass | 10 days |
| Bi-PAP | Days of Hospitalization | Type of OBS: gastroplasty | 6 days |
| Bi-PAP | Days of Hospitalization | Type of OBS: open gastric bypass | 10 days |
Secondary
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
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Sham Bi-PAP | Post-operative Pain | 24h post-op | 6.5 score on a scale | Standard Deviation 1.9 |
| Sham Bi-PAP | Post-operative Pain | 48h post-op | 4.5 score on a scale | Standard Deviation 1.5 |
| Sham Bi-PAP | Post-operative Pain | 72h post-op | 3.3 score on a scale | Standard Deviation 1.2 |
| Bi-PAP | Post-operative Pain | 24h post-op | 6.5 score on a scale | Standard Deviation 1.3 |
| Bi-PAP | Post-operative Pain | 48h post-op | 5.3 score on a scale | Standard Deviation 1.9 |
| Bi-PAP | Post-operative Pain | 72h post-op | 3.5 score on a scale | Standard Deviation 1.4 |