Feasibility of End-tidal Oxygen Concentration Monitoring During Preoxygenation for Intubation in the Intensive Care Unit.

Feasibility of End-tidal Oxygen Concentration Monitoring During Preoxygenation for Intubation in the Intensive Care Unit. First Part, Preliminary Study of the IMPROVE Global Project

Intubation is a common procedure in the intensive care unit. Hypoxemia is the most frequent complication of this procedure.

Monitoring the end-tidal of oxygen is recommended in operating room (OR). End-tidal of oxygen (EtO2) >90% is an indication of a correct preoxygenation.

This monitoring is not used in routine in intensive care unit (ICU). There is no recommendation on the monitoring of end-tidal of oxygen in intensive care unit. In practice, clinicians use pulsed oxygen saturation (SpO2) to determine whether the patient is sufficiently preoxygenated. However, this parameter is not a good indicator of a correct preoxygenation.

In the OR, patients are compliant during the preoxygenation period and the measure of EtO2 with the face mask monitor is considered reliable because i) mask leakage is minimal and ii) the patient can breathe slowly and regularly.

Theses conditions are not available in critical ill patients requiring emergency intubation. EtO2 measured on the facemask may not reflect true EtO2.

This concern about the reliability of EtO2 measurement via the facemask justifies that we conduct a study to compare EtO2 measured on a facemask (facemask EtO2) to EtO2 measured in pharynx (via e nasopharyngeal catheter).

The aim of this study is to determine whether the measurement of EtO2 on facemask is reliable in patients in ICU.

This is a prospective non-comparative interventional study.

A double monitoring of EtO2 will be performed during the procedure of intubation (from the beginning of the preoxygenation to the success of intubation):

• In the pharynx (via a nasopharyngeal catheter) for the needs of the study
• On the facemask (as the practice in the OR) The duration of the study will not exceed one hour, including the installation of the devices.

Inclusion Criteria:

• Age ≥ 18 years
• Requiring an intubation in ICU for acute respiratory failure defined as a respiratory rate ≥ 25/min or clinical signs of respiratory distress or hypoxemia defined as oxygen requirement ≥ 15L/min or FiO2 ≥80% to maintain SpO2 ≥92% or a PaO2/FiO2 ratio <100 mmHg
• With preoxygenation by noninvasive ventilation

Exclusion Criteria:

• Intubation for cardiac arrest
• EtO2 monitoring not available
• Pulsed oxygen saturation monitoring specific for the study not available
• Preoxygenation by high-flow nasal oxygen therapy or bag-mask ventilation
• Allergy to lidocaine (for local nasal anesthesia)
• Previously
• Patient not affiliated or excluded from social protection, or under law protection (namely minors, pregnant or breastfeeding women, persons deprived of their liberty by court or administrative decision)
• Previously included in the study