Obesity, Pulmonary Atelectasis, Respiratory Insufficiency, Respiratory Mechanics, Right-Sided Heart Failure
Conditions
Brief summary
The goal of this interventional crossover study in morbidly obese intubated and mechanically ventilated patients is to describe the respiratory mechanics and the heart-lung interaction at titrated positive end-expiratory pressure levels following a recruitment maneuver with transthoracic echocardiography and electric impedance tomography imaging.
Detailed description
Obese patients under mechanical ventilation are more likely to develop atelectasis as a consequence of the increased abdominal weight. Atelectasis is the primary responsible for respiratory insufficiency and impossibility to wean obese patients from respiratory support. In a previous study we demonstrated the efficacy of the application of titrated PEEP levels following a recruitment maneuver in obese patients, i.e. improvement in respiratory mechanics and gas exchanges without negative hemodynamic effects. The application of lung and heat imaging will allow us to quantitatively describe: * Increase in aerated lung tissue (reduction of atelectasis) * Reduction of over-inflation of the ventilated regions * Recoupling of ventilation and perfusion * Improvement in right heart function by reduction of right heart afterload
Interventions
PROCEDUREPEEP INCREMENTAL
PEEP was progressively increased by steps of 2 cmH2O every 60 second until the end-expiratory transpulmonary pressure became positive between 0-2 cmH2O.
PROCEDUREPEEP DECREMENTAL
Lung recruitment maneuver (LRM) is a transitory and controlled increase in airway pressure to open collapsed alveoli. LRM is the first step of the PEEP DECREMENTAL method. After LRM, PEEP is systematically decreased, in small decrements, until the best respiratory system mechanics is identified.
Sponsors
Massachusetts General Hospital
Study design
Allocation
NON_RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
NONE
Intervention model description
Physiologic crossover study. There is no randomization. All participants will receive the same interventions in the same order.
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* ICU admitted requiring intubation and mechanical ventilation * BMI ≥ 35 kg/m2 * Waist circumference \> 88 cm (for women) * Waist circumference \> 102 cm (for men)
Exclusion criteria
* Known presence of esophageal varices * Recent esophageal trauma or surgery * Severe thrombocytopenia (Platelets count ≤ 5,000/mm3) * Severe coagulopathy (INR ≥ 4) * Presence or history of pneumothorax * Pregnancy * Patients with poor oxygenation index (PaO2/FiO2\< 100 mmHg with at least 10 cmH2O of PEEP) * Pacemaker and/or internal cardiac defibrillator * Hemodynamic parameters: systolic blood pressure (SBP) \<100 mmHg and \>180 mmHg, or if SBP is between 100-180 mmHg on high dose of IV continuous infusion norepinephrine (\>20 μg per minute), or dobutamine (\>10 μg per minute), or dopamine (\>10 μg per Kg per minute), or epinephrine (\>10 μg per minute).
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Respiratory System Elastance | During study time points :baseline, PEEP incremental, PEEP decremental | Difference in Respiratory System Elastance measured in cmH2O/L |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Lung mechanics - Compliance | Study time points: baseline, PEEP incremental, PEEP decremental | Difference in respiratory system, lung and chest wall compliance measured in mL/cmH2O |
| Lung mechanics - Airway resistances | During study time points: baseline, PEEP incremental, PEEP decremental | Difference in resistances of the airways measured as cmH2O/L/sec (Raw) |
| Survival | 28 days after the performance of the study protocol | Incidence of death among the study population |
Other
| Measure | Time frame | Description |
|---|---|---|
| Gas Exchange - Arterial carbon dioxide | Study time points: baseline, PEEP incremental, PEEP decremental. Follow up: 1, 2 , 24 and 48 hours after study procedures | Difference in arterial carbon dioxide measured in mmHg (PaCO2) |
| Electrical Impedance Tomography measurement: lung perfusion | Study time points: baseline, PEEP incremental, PEEP decremental | Differences in distribution in lung perfusion measured as regional percentage of the total cardiac output. |
| Central venous pressure | Study time points: baseline, PEEP incremental, PEEP decremental. Follow up: 1, 2 , 24 and 48 hours after study procedures | Changes in central venous pressure (CVP, mmHg) |
| Lung volumes - respiratory dead space | Study time points: baseline, PEEP incremental, PEEP decremental. | Difference in dead space fraction measured as the ratio of death volume over the total tidal volume (Vd/Vt) |
| Heart rate | Study time points: baseline, PEEP incremental, PEEP decremental. Follow up: 1, 2 , 24 and 48 hours after study procedures | Changes in heart rate (HR, bpm) |
| Blood pressure | A) 48 and 24h before study procedures B)Study time points: baseline, PEEP incremental, PEEP decremental C)Follow up: 1, 2 , 24, 48 and 72 hours after study procedures. | Changes in invasive arterial blood pressures (BP, mmHg) |
| Right heart function -Tricuspid Annular Plane Systolic Excursion (TAPSE) | Study time points: baseline, PEEP incremental, PEEP decremental. Follow up: 1, 2 , 24 and 48 hours after study procedures | Differences in TAPSE measured through two-dimensional transthoracic echocardiography (apical four-chamber view). |
| Right heart function - S' | Study time points: baseline, PEEP incremental, PEEP decremental. Follow up: 1, 2 , 24 and 48 hours after study procedures | Differences in the systolic excursion of the tricuspid annulus measured by tissue doppler imaging. |
| Intra-abdominal pressure | Study time point: baseline | Changes in bladder pressure measured in mmHg. |
| Vasopressor requirement | 48, 24h before AND 24, 48 and 72h after study procedures. | Norepinephrine (mcg/kg/min), epinephrine (mcg/kg/min) , phenylephrine ( mcg/kg/min) and vasopressin (U / min) |
| Creatinine | 48, 24h before AND 24, 48 and 72h after study procedures. | Serum level of creatinine |
| Urinary output | 48, 24h before AND 24, 48 and 72h after study procedures. | Changes in urinary output (mL) |
| Fluid balance | 48, 24h before AND 24, 48 and 72h after study procedures. | Changes in fluid balance (mL) |
| Incidence of tracheostomy | 28 days after the performance of the study protocol | Necessity of tracheostomy for prolonged ventilatory support among the study population |
| Duration of mechanical ventilation | 28 days after the performance of the study protocol | Number of days on mechanical ventilation |
| Intensive care unit length of stay | 28 days after the performance of the study protocol | Numbers of days spent in the intensive care |
| Hospital length of stay | 28 days after the performance of the study protocol | Numbers of days spent in the hospital |
| Right heart function - Tei index | Study time points: baseline, PEEP incremental, PEEP decremental | Differences in global right ventricular function obtained from right ventricle tissue doppler imaging. |
| Electrical Impedance Tomography measurement: collapsed and overdistension | Study time points: baseline, PEEP incremental, PEEP decremental | Percentage of lung tissue collapsed and over distended at different PEEP levels by analyzing pixel compliance ( variation in impedance divided by applied pressure during a respiratory cycle). |
| Gas Exchange - Oxygenation | Study time points: baseline, PEEP incremental, PEEP decremental. Follow up: 1, 2 , 24 and 48 hours after study procedures | Difference in oxygenation measured in mmHg of PaO2/FiO2 |
| Electrical Impedance Tomography measurement: distribution of ventilation | Study time points: baseline, PEEP incremental, PEEP decremental | Difference in end-expiratory lung impedance as percentage estimating the distribution of ventilation among 4 horizontal regions of interest ( from non-dependent to dependent lung regions). |
Countries
United States
Outcome results
None listed