Artificial Respiration

Hospitalization in an intensive care unit (ICU) is accompanied by major physical and emotional stress for patients, a source of discomfort and a risk factor for post-resuscitation syndrome. Efficient patient-caregiver and patient-family communication is needed to: understand the patient's symptoms in order to relieve them, understand the patient's primary needs, understand the patient's questions and concerns in order to respond to them, rehumanize our care and re-establish a more balanced relationship with the patient. However, communication with the patient is often limited, due for example to invasive mechanical ventilation: it is estimated that half of intubated patients meet basic communication criteria (calm patient responding to simple commands and verbal requests) after 2 days of mechanical ventilation, without however being able to express themselves verbally. Augmentative and alternative communication tools exist, ranging from pictograms and slates to voice synthesizers, and are used in ICU. The critical care departments of the University Hospitals of Marseille and Tours use a communication interface consisting of a mobile screen with eye tracking for vigilant patients unable to communicate verbally, which seems to have been appreciated by patients and their families, although its effect has not been measured. Connected glasses are one of the tools available. These are pairs of glasses fitted with infrared sensors that detect a signal predefined with the patient (such as a wink) and thus enable a tablet with customized communication software to be clicked on and navigated. Potential advantages over eye tracking, which has already been used in critical care departments, include: use in low-light conditions, smaller size (no need for an arm to adjust screen orientation), less concentration (eye tracking requires precise, sustained eye fixation). The objective is to conduct a pilot study to assess the feasibility of using this tool in non temporarily speaking patients hospitalized in ICU.

Conventional continuous mandatory mechanical ventilation relies on the passive recoil of the chest wall for expiration. This results in an exponentially decreasing expiratory flow. Flow controlled ventilation (FCV), a new ventilation mode with constant, continuous, controlled expiratory flow, has recently become clinically available and is increasingly being adopted for complex mechanical ventilation during surgery. In both clinical and pre-clinical settings, an improvement in ventilation (CO2 clearance) has been observed during FCV compared to conventional ventilation. Recently, Schranc et al. compared flow-controlled ventilation with pressure-regulated volume control in both double lung ventilation and one-lung ventilation in pigs. They report differences in dead space ventilation that may explain the improved CO2 clearance, although their study was not designed to compare dead space ventilation within the group of double lung ventilation. Dead space ventilation, or "wasted ventilation", is the ventilation of hypoperfused lung zones, and is clinically relevant, as it is a strong predictor of mortality in patients with the acute respiratory distress syndrome (ARDS) and is correlated with higher airway driving pressures which are thought to be injurious to the lung (lung stress). This trial aims to study the difference in dead space ventilation between conventional mechanical ventilation in volume-controlled mode and flow controlled-ventilation.