Chest Wall Influence on Respiratory System Mechanics in Morbidly Obese Patients

Obesity Clinical Trial

Official title:

Chest Wall Influence on Respiratory System Mechanics in Morbidly Obese Patients

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT02105220
• Other study ID #: 2013P001413
• Status: Completed
• Phase: N/A
• First received: February 12, 2014
• Last updated: March 24, 2015
• Start date: August 2013
• Est. completion date: March 2015

Study information

• Verified date: March 2015
• Source: Massachusetts General Hospital
• Contact: n/a
• Is FDA regulated: No
• Health authority: United States: Institutional Review Board
• Study type: Observational

Clinical Trial 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.

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 14
• Est. completion date: March 2015
• Est. primary completion date: January 2015
• Accepts healthy volunteers: No
• Gender: Both
• Age group: 18 Years and older

Eligibility

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)

Study Design

Observational Model: Case-Only, Time Perspective: Prospective

Related Conditions & MeSH terms

• Intra-Abdominal Hypertension
• Obesity

Intervention

Other:
• 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.

Locations

Country	Name	City	State
United States	Massachusetts General Hospital	Boston	Massachusetts

Sponsors (1)

Lead Sponsor	Collaborator
Massachusetts General Hospital

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	End Expiratory Lung Volumes	EELV variation at different levels of PEEP in mechanically ventilated and sedated morbidly obese patients and patients with intraabdominal hypertension	2 hours	No
Secondary	Respiratory mechanics	Evaluation of effects of PEEP level set by ICU staff on respiratory mechanics after 24 hours from enrollment Evaluation of PEEP level set by ICU staff	24 hours	No
Secondary	Work of breathing	Evaluation of work of breathing variation at different level of PEEP during spontaneous breathing and ventilation weaning in morbidly obese patients	20 minutes	No
Secondary	Respiratory mechanics	Respiratory mechanics variation at different levels of PEEP in mechanically ventilated and sedated morbidly obese patients and patients with intraabdominal hypertension	2 hours	No
Secondary	Gas Exchange	Gas exchange variation at different levels of PEEP in mechanically ventilated and sedated morbidly obese patients and patients with intraabdominal hypertension	2 hours	No
Secondary	Respiratory mechanics	Evaluation of respiratory mechanics at different level of PEEP during spontaneous breathing and ventilation weaning in morbidly obese patients	20 minutes	No
Secondary	Gas exchange	Evaluation of gas exchange variation at different level of PEEP during spontaneous breathing and ventilation weaning in morbidly obese patients	20 minutes	No
Secondary	End Expiratory Lung Volume	Evaluation of effects of PEEP level set by ICU staff on EELV after 24 hours from enrollment	24 hours	No
Secondary	Gas Exchange	Evaluation of effects of PEEP level set by ICU staff on gas exchange after 24 hours from enrollment	24 hours	No