Chest Wall Influence on Respiratory System Mechanics in Morbidly Obese Patients

NCT ID: NCT02105220

Last Updated: 2015-03-25

Basic Information

• Recruitment Status: COMPLETED
• Total Enrollment: 14 participants
• Study Classification: OBSERVATIONAL
• Study Start Date: 2013-08-31
• Study Completion Date: 2015-03-31

Brief Summary

The goal of this study is to describe the influence of the chest wall on the respiratory system mechanics in morbidly obese patients and in patients with high intra-abdominal pressure.

The effects of increasing and decreasing positive end-expiratory pressure (PEEP) on chest wall and total respiratory system mechanics, lung volumes and gas exchange will be evaluated, both during controlled and assisted mechanical ventilation.

Patients will be studied, first, during the acute phase of respiratory failure, when requiring intubation and controlled mechanical ventilation. Then, patients will be evaluated again during weaning from the ventilator to assess the influence of PEEP in assisted ventilation prior to extubation.

Detailed Description

The goal of this study is to describe the influence of the chest wall on the respiratory system mechanics. Investigators want to describe how extreme obesity and Intra-Abdominal Hypertension (IAH) affect normal respiratory system behavior. The effects of increasing and decreasing positive end-expiratory pressure (PEEP) on respiratory system mechanics, lung volumes and gas exchange will be evaluated, both during controlled and assisted mechanical ventilation.

Investigators will record and compare lung volumes, airway and transpulmonary pressure, gas exchange and hemodynamic changes caused by variations of PEEP. Patients will be studied, first, during the acute phase of respiratory failure, when requiring intubation and controlled mechanical ventilation. Patients will then again be evaluated during weaning from the ventilator to assess the influence of PEEP in assisted ventilation prior to extubation.

Investigators believe that assessment of the transpulmonary pressure and lung volumes is essential to correctly evaluate respiratory system function in patients in which the relationship between the lung and chest wall is altered. Improper mechanical ventilation leads to lung damage. High ventilatory volume/pressure are associated with lung overdistension, while low volume/pressure leads to lung collapse and cyclic opening and closing of alveoli. All of these mechanisms have been associated with ventilator induced lung injury and poorer outcomes. Adequate PEEP and transpulmonary pressure are fundamental in preventing this vicious cycle.

Conditions

Obesity; Intra-Abdominal Hypertension

Study Design

• Observational Model Type: CASE_ONLY
• Study Time Perspective: PROSPECTIVE

Study Groups

Obese

We will enroll patients with BMI≥40 kg/m2 to describe the impact of obesity on chest wall compliance and respiratory mechanics.

Respiratory mechanics assessment: We will assess respiratory mechanics through different end expiratory pressure settings and recording airway and esophageal pressure tracings.

Respiratory mechanics assessment

Intervention Type: OTHER

Data collection on respiratory mechanics, end expiratory lung volumes, gas exchanges, work of breathing. Data will be obtained by setting different end expiratory pressures and recording esophageal and airways pressure tracings.

Intraabdominal Hypertension

We will enroll patients with IAP≥12 mmHg to describe the impact of intraabdominal hypertension on chest wall compliance and respiratory mechanics.

Respiratory mechanics assessment: We will assess respiratory mechanics through different end expiratory pressure settings and recording airway and esophageal pressure tracings.

Respiratory mechanics assessment

Intervention Type: OTHER

Data collection on respiratory mechanics, end expiratory lung volumes, gas exchanges, work of breathing. Data will be obtained by setting different end expiratory pressures and recording esophageal and airways pressure tracings.

Interventions

Respiratory mechanics assessment

Data collection on respiratory mechanics, end expiratory lung volumes, gas exchanges, work of breathing. Data will be obtained by setting different end expiratory pressures and recording esophageal and airways pressure tracings.

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• 18 years or older
• Requiring intubation and mechanical ventilation
• BMI≥40 kg/m2 or IAP≥12 mmHg

Exclusion Criteria

• Known presence esophageal varices
• Recent esophageal trauma or surgery
• Severe thrombocytopenia (PTL≤10,000/mm3)
• Severe coagulopathy (INR≥2)
• Presence of pneumothorax
• Pregnancy
• Patients with diagnosed moderate to severe ARDS or with poor oxygenation index (PaO2/FiO2 < 200 mmHg)

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Massachusetts General Hospital

OTHER

Sponsor Role: lead

Responsible Party

Robert M. Kacmarek

PhD RRT

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Robert M Kacmarek, PhD RRT

Role: PRINCIPAL_INVESTIGATOR

Massachusetts General Hospital

Locations

Massachusetts General Hospital

Boston, Massachusetts, United States

Countries

United States

Other Identifiers

2013P001413

Identifier Type: -

Identifier Source: org_study_id