Acute Hypoxic Respiratory Failure
Conditions
Brief summary
The optimal noninvasive respiratory support for acute hypoxemic respiratory failure is debated. Recent preliminary data indicate that both pressure-support noninvasive ventilation (NIV) and continuous-positive airway pressure (CPAP) may be of benefit. While often applied interchangeably in clinical practice, NIV and CPAP have different effects on the inspiratory effort, which is the major determinant of self-inflicted lung injury. Also, inspiratory effort widely varies among individuals. The purpose of this study is to assess the physiological effects of a noninvasive respiratory support approach guided by inspiratory effort, as compared to CPAP and NIV, in patients with moderate-to-severe acute hypoxemic respiratory failure.
Detailed description
Patients with acute hypoxemic respiratory failure will undergo a decremental pressure-support trial during helmet noninvasive support. The following pressure-support settings will be applied sequentially, with positive end-expiratory pressure kept constant and equal to 10-12 cmH2O: 20 cmH2O, 16 cmH2O, 12 cmH2O, 8 cmH2O and high-flow-driven CPAP. Inspiratory effort will be monitored during the trial through esophageal manometry. The personalized setting of noninvasive support will be defined as the minimal pressure-support level capable of generating inspiratory effort between 5 and 10 cmH2O. Personalized noninvasive support will be then compared to conventionally-set NIV and CPAP in a randomized cross-over trial.
Interventions
DEVICENoninvasive support
Noninvasive respiratory support delivered through a helmet
Sponsors
Fondazione Policlinico Universitario Agostino Gemelli IRCCS
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Acute hypoxemic respiratory failure and PaO2/FiO2\<200 mmHg * PaCO2\<45 mmHg * Respiratory failure not caused by exacerbation of chronic pulmonary disease, cardiac failure or fluid overload
Exclusion criteria
* Pregnancy * Contraindication to helmet support * Contraindication to esophageal manometry * Contraindication to electrical-impedance tomography monitoring * Recent surgery involving the abdomen or the thorax * Pneumothorax or documented barotrauma
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Tidal volume | 1 hour | Tidal volume size, assessed with electrical impedance tomography |
| Transpulmonary driving pressure | 1 hour | The positive inspiratory swing in transpulmonary pressure, calculated as airway pressure minus esophageal pressure |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Blood oxygenation | 1 hour | PaO2/FiO2 ratio |
| Work of breathing | 1 hour | Simplified esophageal pressure pressure-time product |
| Corrected minute ventilation | 1 hour | Minute ventilation (assessed with electrical impedance tomography) normalized to PaCO2 |
| Tidal volume distribution | 1 hour | Tidal volume distribution in the four lung regions of interest (ventral, mid-ventral, mid-dorsal and dorsal), assessed with electrical impedance tomography |
| Inspiratory effort | 1 hour | Inspiratory effort, defined as the negative deflection in esophageal pressure |
| Pendelluft extent | 1 hour | Pendelluft, assessed with electrical impedance tomography and expressed in % of tidal volume size |
| Lung compliance | 1 hour | Defined as the ration of tidal volume to transpulmonary driving pressure |
| Dyspnea | 1 hour | Dyspnea, defined through a visual analog scale ((ranging from 0 to 10, with representing most severe dyspnea) |
| End-expiratory lung impedance | 1 hour | End-expiratory lung impedance, assessed with electrical impedance tomography |
| Respiratory rate | 1 hour | Respiratory rate per minute |
Countries
Italy
Outcome results
None listed