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Ventilation Distribution After Bariatric Surgery

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ClinicalTrials.gov Identifier: NCT03975348
Recruitment Status : Recruiting
First Posted : June 5, 2019
Last Update Posted : June 5, 2019
Sponsor:
Information provided by (Responsible Party):
Lucia Comuzzi, University of Trieste

Brief Summary:
Obese patients have an increased risk of developing post-operative respiratory complications due to their comorbidities. They have a restrictive ventilatory defect with reduction of lung volumes and expiratory flow limitation, higher airway resistance and collapsibility of the upper respiratory tract. These abnormalities are worsened by general anesthesia and opioid administration. It has been proved that oxygen therapy with HFNC (high flow nasal cannula) increases lung volumes through a continuous positive airway pressure (CPAP)-effect. This also improves gas exchange and decreases anatomical dead space. At the present time, CPAP represents the gold standard for the prevention of postoperative pulmonary complications. The purpose of this study is to evaluate lung ventilation, gas exchange and comfort with HFNC compared with CPAP during the post-operative period in patients who undergo laparoscopic bariatric surgery.

Condition or disease Intervention/treatment Phase
Bariatric Surgery Candidate Atelectasis, Postoperative Pulmonary Device: High flow nasal cannula Device: Continuous positive airway pressure Device: Facemask Not Applicable

Detailed Description:
Immediately after bariatric surgery, patients will follow a pre-determined schedule of oxygen therapy with conventional facemask (from the beginning to minute 10), HFNC (with a flow of 40 L/min from minute 11 to 20, 60 L/min from minute 21to 30, 80 L/min from minute 31 to 40, 100 L/min from minute 41 to 50, 80 L/min from minute 51 to 60, 60 L/min from minute 61 to 70, 40 L/min from minute 71 to 80), conventional facemask again (washout, from minute 81 to 90) and CPAP (10 cmH2O, from minute 91 to 100). Lung ventilation will be evaluated with electrical impedance tomography (EIT), which measures thoracic impedance variations related to changes in lung aeration. At the end of each 10 minutes-period the following data will be collected: electrical impedance tomography data (to calculate the global inhomogeneity index, Δ end-expiratory lung impedance and tidal impedance variation), hemodynamic parameters, respiratory rate, SpO2, pain (numerical rating scale), level of sedation (Ramsey score) and patient comfort (modified Borg scale). An arterial blood gas will be collected at the end of the following steps: baseline facemask, HFNC 40 and 100 L/min, washout facemask and CPAP. Data about anesthetic/analgesic drugs and ventilation parameters will also be collected.

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 15 participants
Allocation: Non-Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Evaluation of Ventilation Distribution After Bariatric Surgery - High Flow Nasal Cannulas Versus Continuous Positive Airway Pressure
Actual Study Start Date : April 15, 2019
Estimated Primary Completion Date : August 31, 2019
Estimated Study Completion Date : August 31, 2019

Resource links provided by the National Library of Medicine


Arm Intervention/treatment
Baseline conventional facemask
The patients will receive oxygen therapy through conventional facemask for 10 minutes
Device: Facemask
Oxygen therapy through a conventional facemask

Experimental: HFNC 40 L/min up
The patients will receive oxygen/air mixture through high flow nasal cannula at incremental, then decremental flows, starting at 40 L/min for 10 minutes
Device: High flow nasal cannula
High flow of warm and humidified oxygen/air mixture delivered through nasal cannula

Experimental: HFNC 60 L/min up
High flow nasal cannula at 60 L/min for 10 minutes
Device: High flow nasal cannula
High flow of warm and humidified oxygen/air mixture delivered through nasal cannula

Experimental: HFNC 80 L/min up
High flow nasal cannula at 80 L/min for 10 minutes
Device: High flow nasal cannula
High flow of warm and humidified oxygen/air mixture delivered through nasal cannula

Experimental: HFNC 100 L/min
High flow nasal cannula at 100 L/min for 10 minutes
Device: High flow nasal cannula
High flow of warm and humidified oxygen/air mixture delivered through nasal cannula

Experimental: HFNC 80 L/min down
High flow nasal cannula at 80 L/min for 10 minutes
Device: High flow nasal cannula
High flow of warm and humidified oxygen/air mixture delivered through nasal cannula

Experimental: HFNC 60 L/min down
High flow nasal cannula at 60 L/min for 10 minutes
Device: High flow nasal cannula
High flow of warm and humidified oxygen/air mixture delivered through nasal cannula

Experimental: HFNC 40 L/min down
High flow nasal cannula at 40 L/min for 10 minutes
Device: High flow nasal cannula
High flow of warm and humidified oxygen/air mixture delivered through nasal cannula

Washout conventional facemask
Again, the patients will receive oxygen therapy through conventional facemask for 10 minutes, to reduce the influence of HFNC on CPAP therapy
Device: Facemask
Oxygen therapy through a conventional facemask

Active Comparator: CPAP
The patients will receive CPAP at 10 cmH2O for 10 minutes
Device: Continuous positive airway pressure
Positive airway pressure applied through a sealed face mask




Primary Outcome Measures :
  1. Change of global inhomogeneity index [ Time Frame: The data needed to calculate the index will be collected at minute 10, 20, 30, 40, 50, 60, 70, 80, 90 and 100 (i.e. at the end of every step of oxygen therapy). The values obtained will then all be compared each other. ]
    This parameter, calculated from data collected with EIT, evaluates lung ventilation distribution. To calculate this index, the median value of regional impedance changes from ventilated regions within the tidal image has to be computed, then the sum of differences between the median and every pixel value needs to be calculated, and the result must be normalised by the sum of impedance values within the lung area. The minimum value of the index is 0 and corresponds to homogeneous ventilation, whereas the maximum value is 1 and corresponds to inhomogeneous ventilation (in this context likely due to atelectasis).


Secondary Outcome Measures :
  1. Change of Δ end expiratory lung impedance (ΔEELI) [ Time Frame: The data will be collected at minute 10, 20, 30, 40, 50, 60, 70, 80, 90 and 100 (i.e. at the end of every step of oxygen therapy). The values obtained will then all be compared each other. ]
    The parameter, measured with EIT, expresses deviations of the regional end-expiratory lung impedance in relation to the global tidal impedance variation. ΔEELI closely correlates with changes of end-expiratory lung volume of the EIT sensitivity region.

  2. Change of tidal impedance variation [ Time Frame: The data will be collected at minute 10, 20, 30, 40, 50, 60, 70, 80, 90 and 100 (i.e. at the end of every step of oxygen therapy). The values obtained will then all be compared each other. ]
    This parameter, measured with EIT, corresponds to the difference between end-expiratory and end-inspiratory lung impedance and is related to tidal volume. It will be expressed in units, where one unit corresponds to the tidal impedance variation of the patient breathing with baseline conventional facemask.

  3. Change of oxygenation [ Time Frame: The blood gas analysis will be performed at minute 10, 20, 50, 90 and 100. The values will then all be compared each other. ]
    Oxygen arterial partial pressure

  4. Change of carbon dioxide [ Time Frame: The blood gas analysis will be performed at minute 10, 20, 50, 90 and 100. The values will then all be compared each other. ]
    Carbon dioxide arterial partial pressure

  5. Change of pH [ Time Frame: The blood gas analysis will be performed at minute 10, 20, 50, 90 and 100. The values will then all be compared each other. ]
    Arterial pH

  6. Change of respiratory rate [ Time Frame: The parameter will be collected at minute 10, 20, 30, 40, 50, 60, 70, 80, 90 and 100 (i.e. at the end of every step of oxygen therapy). The values obtained will then all be compared each other. ]
    Respiratory rate

  7. Change of patient's comfort: modified Borg dyspnea scale [ Time Frame: The parameter will be collected at minute 10, 20, 30, 40, 50, 60, 70, 80, 90 and 100 (i.e. at the end of every step of oxygen therapy). The values obtained will then all be compared each other. ]
    Comfort related to the oxygen therapy will be evaluated with the modified Borg dyspnea scale (0: nothing at all, 0.5: very, very slight, 1: very slight, 2: slight, 3: moderate, 4: somewhat severe, 5: severe, 6, 7: very severe, 8, 9: very, very severe - almost maximal, 10: maximal)



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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

  • Patient's consent to the trial
  • Candidate to laparoscopic bariatric surgery (sleeve gastrectomy or Roux-en-Y gastric bypass)
  • BMI 35-50 kg/m2
  • ASA class 1-3

Exclusion Criteria:

  • Obesity hypoventilation syndrome
  • Contraindication to EIT (e.g. implantable cardioverter-defibrillator)

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03975348


Contacts
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Contact: Lucia Comuzzi 00393297835749 lucia.comz@gmail.com

Locations
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Italy
Azienda Sanitaria Universitaria Integrata di Trieste Recruiting
Trieste, Italy, 34100
Contact: Lucia Comuzzi    00393297835749    lucia.comz@gmail.com   
Contact: Enrico Lena    00393488427261    enrico.aj.lena@gmail.com   
Sponsors and Collaborators
University of Trieste
Investigators
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Principal Investigator: Lucia Comuzzi Azienda Sanitaria Universitaria Integrata di Trieste

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Responsible Party: Lucia Comuzzi, Principal investigator, University of Trieste
ClinicalTrials.gov Identifier: NCT03975348     History of Changes
Other Study ID Numbers: 123/2018
First Posted: June 5, 2019    Key Record Dates
Last Update Posted: June 5, 2019
Last Verified: June 2019
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Product Manufactured in and Exported from the U.S.: No

Keywords provided by Lucia Comuzzi, University of Trieste:
High flow nasal cannula
Bariatric surgery
Postoperative atelectasis
Electrical impedance tomography

Additional relevant MeSH terms:
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Pulmonary Atelectasis
Lung Diseases
Respiratory Tract Diseases