Hypoxemia, Respiratory Failure
Conditions
Brief summary
The investigators designed a cross-over, randomized trial to assess the physiological effects of helmet pressure support ventilation (PSV) and continuous positive airway pressure (CPAP) as compared to high-flow nasal cannula during the early phase of acute hypoxemic respiratory failure
Detailed description
Setting: 21-bed general ICU, emergency room of the Emergency department (ED), Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy.. Patients: adult hypoxemic non-hypercapnic patients admitted to the emergency department or the ICU with de novo acute respiratory failure will be assessed for the enrolment. Each eligible patient, in the absence of exclusion criteria, will receive 15 minutes of heated and humidified 60% oxygen at a rate of 50 l/min via a non-rebreathing face mask. An ABG will be then collected and PaO2/FiO2 ratio computed: given the high flows used, actual FiO2 will be approximated to the set one. Nonhypercapnic patients with a PaO2/FiO2≤200 mmHg will be enrolled. In the absence of exclusion criteria and if all other inclusion in criteria are met, patients showing PaO2/FiO2≤300 and \>200 mmHg will be treated according to the clinical practice eventually reassessed for the presence of oxygenation criterion subsequently. Enrolled patients will receive all the interventions (helmet CPAP, PSV and high-flow nasal cannula) in a randomized, cross-over fashion, for 40 minutes each. At the end of the study, the patient will receive the treatment that will be shown as more appropriate for the patient, according to the attending physician, who will be informed about the results of the study on the individual patient.
Interventions
OTHERRespiratory support (High-flow oxygen therapy)
Noninvasive respiratory support respiratory support
OTHERRespiratory support (Helmet PSV)
Noninvasive respiratory support respiratory support
OTHERRespiratory support (Helmet CPAP)
Noninvasive respiratory support respiratory support
Sponsors
Societa Italiana Anestesia Analgesia Rianimazione e Terapia Intensiva
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
Patients: adult hypoxemic non-hypercapnic patients admitted to the emergency department or the ICU with de novo acute respiratory failure will be assessed for the enrolment. Patients will be considered eligible whether all the following inclusion criteria are met: 1. Respiratory rate\>25 bpm. 2. PaO2/FiO2 ≤200 in the supine position, measured after 15 minutes of high flow treatment with face mask (60 l/min, temperature of the humidification chamber set at 37°C, FiO2 set to achieve a SpO2 \>92% and \<98%). Given the use of the high flows, nominal FiO2 will be considered a reliable estimate of the actual one. 3. PaCO2 \<45mmHg 4. Absence of history of chronic respiratory failure or moderate to severe cardiac insufficiency. 5. Written informed consent
Exclusion criteria
* Exacerbation of asthma or chronic obstructive pulmonary disease; * Cardiogenic pulmonary oedema; * Haemodynamic instability (Systolic blood pressure \<90 mmHg or mean arterial pressure \<65 mmHg) and/or lactic acidosis (lactate \>5 mmol/L) and/or clinically diagnosed Shock * Metabolic Acidosis (pH \<7.30 with normal- or hypo-carbia); * Glasgow coma scale \<13; * Recent head surgery or anatomy that prevent the application of helmet or nasal cannula to patient's face.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Inspiratory effort | 40 minutes | The negative deflection in esophageal pressure during inspiration |
| Tidal volume | 40 minutes | The tidal change in lung impedance, assessed by electrical impedance tomography |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Carbon dioxide | 40 minutes | Blood carbon dioxide, measured with the arterial blood gas analysis |
| Respiratory rate | 40 minutes | Respiratory rate/minute, assessed with the esophageal pressure |
| Dyspnea | 40 minutes | Dyspnea assessed with the visual analog scale, 0-10 scale where the highest value corresponds to the highest degree of dyspnea |
| Comfort | 40 minutes | Comfort assessed with the visual analog scale, 0-10 scale where the highest value corresponds to the highest degree of discomfort |
| Global impedance-derived End-expiratory lung volume | 40 minutes | End-expiratory lung volume, measured with electrical impedance tomography |
| Regional impedance-derived End-expiratory lung volume | 40 minutes | End-expiratory lung impedance in the four regions of the lungs (ventral, mid-ventral, mid-dorsal, dorsal), measured with electrical impedance tomography |
| Oxygenation | 40 minutes | Ratio of PaO2 to FiO2 |
| Global impedance-derived lung dynamic strain | 40 minutes | Change in impedance due to tidal volume / end expiratory lung impedance, both measured with electrical impedance tomography |
| Regional impedance-derived lung dynamic strain | 40 minutes | Change in impedance due to tidal volume / end expiratory lung impedance in the four regions of the lungs (ventral, mid-ventral, mid-dorsal, dorsal), measured with electrical impedance tomography |
| Respiratory system dynamic compliance | 40 minutes | Ratio of the tidal change in lung impedance to dynamic transpulmonary driving pressure |
| Pendelluft | 40 minutes | Occurrence of intra-tidal shift of gas within different lung regions at beginning of inspiration |
| Work of breathing | 40 minutes | Esophageal pressure simplified pressure time product per minute |
| Dynamic transpulmonary driving pressure | 40 minutes | The tidal change in transpulmonary pressure |
| Tidal volume distribution | 40 minutes | Distribution of tidal volume within the lung regions, assessed by electrical impedance tomography |
Countries
Italy
Outcome results
None listed