Use of Airway Pressure Release Ventilation in Morbidly Obese Patients Undergoing Open Heart Surgery

December 30, 2022 updated by: Mohamed Alaaeldin Abdelmoneem Alhadidy, Ain Shams University

Use of Airway Pressure Release Ventilation in Morbidly Obese Patients Undergoing Open Heart Surgery to Improve Post Operative Pulmonary Outcomes

The goal of this Randomized Clinical trial is to to investigate if the use of Air Pressure Release Ventilation in morbidly obese patients undergoing open heart surgery will improve post operative pulmonary outcomes 60 Patients will be randomized into two groups according to the mode of ventilation used into: Group A: airway pressure release ventilation (APRV) group (30 Patients) Group B: Standard (control) group (30 Patients) Post-operatively, Patients will be ventilated with conventional Synchronized Intermittent Mandatory Ventilation (SIMV) volume control mode

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

Obesity is an ongoing worldwide problem, and as such, weight-related issues arise especially in the intensive care unit (ICU). Morbid obesity adversely affects physiology; restricted thoracic movement and increased intra-abdominal pressure leads to reduced lung volumes and compliance resulting frequently in atelectasis, ventilation-perfusion mismatch.

Cardiac surgical patients are at particular risk for PPCs. The use of cardiopulmonary bypass (CPB) is responsible for a systemic inflammatory response and oxidative stress, leading to pulmonary ischemia-reperfusion injury. Mechanical ventilation frequently is disrupted during CPB, thus inducing atelectasis. Some proposed mechanisms are leukocyte activation, fluid accumulation in the lung and atelectasis.

Atelectasis is a highly prevalent pulmonary complication in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) and an important cause of postoperative hypoxemia. Pulmonary collapse occurs early after the induction of anesthesia and persists for several days postoperatively. Studies based on thoracic computed tomography (CT) have shown that pulmonary collapse is mainly distributed to the dependent regions close to the diaphragm and may encompass up to 35% of the overall lung parenchyma which predispose to pneumonia.

This impairment of lung function, particularly oxygenation of the blood, is a common and potentially serious complication after cardiac surgery. It has been shown to persist for as long as one week after the operation.

In obese patients, the functional residual capacity (FRC) and lung compliance are reduced, and thus the elastic work of breathing (WOB) is elevated. By applying continuous positive airway pressure (CPAP), the FRC is restored, and inspiration starts from a more favorable pressure-volume relationship, facilitating spontaneous ventilation, and improves oxygenation.

APRV was originally described as a mode to treat acute lung injury in patients and attempt to maintain the level of airway pressure without reducing cardiac function, delivering mechanical breaths without excessive airway pressure and allowing unrestricted spontaneous ventilation. 6 APRV is essentially a high-level continuous positive airway pressure (CPAP) mode that is terminated for a very brief period of time. It is this short release period that allows carbon dioxide to be cleared. The lengthy time during which the high-level CPAP is present results in substantial recruitment of alveoli of markedly different regional time constants, at rather low gas flow rates and lower airway pressures. The establishment of intrinsic PEEP by the short release time enhances oxygenation. Carbon dioxide clearance is aided by recruitment of the patient's lung at close to total lung capacity; elastic recoil creates large volume gas flow during the release period.

Recent advances in the understanding of the respiratory physiologic alterations in the obese patient suggest that ''open lung'' ventilation approaches such as APRV recruit lung alveolar volumes without exacerbating lung injury and maintain acceptable gas exchange. Given the spontaneous nature of the mode, it is hypothesized that there should be no need for continuous infusions of neuromuscular blocking agents in patients placed on this mode of ventilation.

This may result in a shorter duration of intensive care unit (ICU) stay. Furthermore, because patients may be ventilated at lower airway pressures than are required with cyclic ventilation, there may be a reduced need for pressor support of hemodynamics to ensure oxygen delivery which is favorable in cardiac surgical patients.

So, the investigators hypothesize that APRV may be a preferred mode of ventilation in morbidly obese patients after cardiac surgery.

Study Type

Interventional

Enrollment (Anticipated)

60

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Egypt
      • Cairo, Egypt, 11566
        • Recruiting
        • Cardiothoracic Academy, Ain Shams University Hospitals
        • Contact:
        • Principal Investigator:
          • Mohamed A. Alhadidy, MD
        • Sub-Investigator:
          • Mohamed M. Ellewa, MD
        • Sub-Investigator:
          • Ahmed M. Eldemerdash, MD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Age ≥18 y.
  • Scheduled for open heart Surgery with cardiopulmonary bypass (CPB) pump.
  • Class III Obesity (Morbid obesity): BMI ≥ 40.0 kg/m².

Exclusion Criteria:

  • Patients with obstructive lung disease (asthma or chronic obstructive pulmonary disease).
  • Pneumothorax or Surgical emphysema.
  • Mechanical ventilation prior to the operation.
  • Patient Refusal.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: APRV group

Group A: APRV group (30 Patients) Post operatively, Patients will be ventilated with APRV mode using GE Carescape R860 ventilator Initial Settings15

  1. P high at the P plateau (or desired P mean + 3cm H2O). keep P high below 30-35 cm H2O
  2. T high at 4-6 seconds
  3. P low at 0
  4. T low at 0.5 to 0.8 seconds.
  5. ATC (automatic tube compensation) on.
  6. FIO2: 40% Ventilator settings will be adjusted to keep Pco2 between 35-45 mmhg, PO2 > 60 mmhg on FIO2 < 50 % Once Patients are fully conscious and after complete recovery of reflexes with no postoperative bleeding nor hemodynamic instability, weaning of APRV will start as following, P-High will be lowered 2 or 3 cm of H2O pressure at a time, and T Low will be lengthened in 0.5-2.0 s increments, depending on patient tolerance. When the P-high reaches 10 cmH2O and the Thigh reaches 12-15 seconds, change the mode to pressure support (PS) mode PS of 7-8 cmH20 above PEEP of cmh2o then extubation.
Device: Use Of APRV mode of Ventilation

Post operatively, Patients will be ventilated with APRV mode using GE Carescape R860 ventilator Initial Settings15

  1. P high at the P plateau (or desired P mean + 3cm H2O). keep P high below 30-35 cm H2O
  2. T high at 4-6 seconds
  3. P low at 0
  4. T low at 0.5 to 0.8 seconds.
  5. ATC (automatic tube compensation) on.
  6. FIO2: 40% Ventilator settings will be adjusted to keep Pco2 between 35-45 mmhg, PO2 > 60 mmhg on FIO2 < 50 % Once Patients are fully conscious and after complete recovery of reflexes with no postoperative bleeding nor hemodynamic instability, weaning of APRV will start as following, P-High will be lowered 2 or 3 cm of H2O pressure at a time, and T Low will be lengthened in 0.5-2.0 s increments, depending on patient tolerance. When the P-high reaches 10 cmH2O and the Thigh reaches 12-15 seconds, change the mode to pressure support (PS) mode PS of 7-8 cmH20 above PEEP of cmh2o then extubation.
Active Comparator: Standard group

Group B: Standard (control) group (30 Patients) Post-operatively, Patients will be ventilated with conventional Synchronized Intermittent Mandatory Ventilation (SIMV) volume control mode using GE Carescape R860 ventilator Initial Settings: 16

  1. Tidal Volume 6-8 ml/kg predicted body weight
  2. Respiratory rate (RR) 14 /min
  3. Positive end expiratory pressure (PEEP)= 5 cmH2o
  4. Pressure Support (PS) = 10 cmH2o
  5. Inspiratory time 1.4 Sec
  6. FIO2: 40% Ventilator settings will be adjusted to keep Pco2 between 35-45 mmhg, PO2 > 60 mmhg on FIO2 < 50 %
Device: Use of conventional Synchronized Intermittent Mandatory Ventilation (SIMV) volume control mode

Post-operatively, Patients will be ventilated with conventional Synchronized Intermittent Mandatory Ventilation (SIMV) volume control mode using GE Carescape R860 ventilator Initial Settings: 16

  1. Tidal Volume 6-8 ml/kg predicted body weight
  2. Respiratory rate (RR) 14 /min
  3. Positive end expiratory pressure (PEEP)= 5 cmH2o
  4. Pressure Support (PS) = 10 cmH2o
  5. Inspiratory time 1.4 Sec
  6. FIO2: 40% Ventilator settings will be adjusted to keep Pco2 between 35-45 mmhg, PO2 > 60 mmhg on FIO2 < 50 % Once Patients are fully conscious and after complete recovery of reflexes with no postoperative bleeding nor hemodynamic instability, weaning of mechanical ventilation will be done by switching the ventilation to pressure support (PS) mode PS of 7-8 cmH20 above PEEP of cmh2o then extubation.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
PO2/FIO2 (P/F) ratio
Time Frame: up to 3 days
Will be recorded at admission, 6 hours,12 hours, 24 hours and 48 hours
up to 3 days
Time of mechanical ventilation
Time Frame: up to 3 days
Hours of Mechanical ventilation
up to 3 days

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Need for Non-Invasive ventilation (NIV)
Time Frame: up to 3 days
Need of high flow nasal cannula (HFNC) or Non-Invasive continuous positive airway pressure (NICPAP)
up to 3 days
Occurrence Respiratory complications
Time Frame: up to 1 week
Occurrence of Pneumonia identified by clinical signs, chest Xray and lung ultrasound
up to 1 week
Effect on Blood pressure
Time Frame: up to 1 day
Mean arterial systemic blood pressure (MAP) recorded at admission, 6 hours, 12 hours and 24 hours
up to 1 day
Need for Vasopressors and Inotropes
Time Frame: up to 1 day
Vasopressors and Inotropes needs guided by Vasoactive-Inotrope score (VIS) measured at admission, 6 hours, 12 hours and 24 hours
up to 1 day
length of ICU stay
Time Frame: up to 3 days
Duration of patient stays in ICU in days
up to 3 days
length of Hospital stay
Time Frame: up to 10 days
Duration of hospital stay after surgery in days.
up to 10 days
Mortality
Time Frame: up to 30 days
Post operative Death
up to 30 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Ain Shams University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

December 3, 2022

Primary Completion (Anticipated)

May 3, 2023

Study Completion (Anticipated)

June 1, 2023

Study Registration Dates

First Submitted

December 8, 2022

First Submitted That Met QC Criteria

December 30, 2022

First Posted (Actual)

January 4, 2023

Study Record Updates

Last Update Posted (Actual)

January 4, 2023

Last Update Submitted That Met QC Criteria

December 30, 2022

Last Verified

December 1, 2022

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • FMASU R 243/2022

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

Undecided

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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