Determination of the Optimal Spontaneous Breathing Trial During Weaning of Mechanical Ventilation

Determination of the Optimal Spontaneous Breathing Trial During Weaning of Mechanical Ventilation: a Randomized and Personalized Cross Over Physiologic Study in the Perioperative and Critically Ill Patient

Assessment and comparison of three spontaneous breathing trials in five specific profiles of intensive care unit and perioperative patients. A physiological cross over study

Mechanical ventilation is the most used organ replacement therapy in intensive care unit (ICU). After resolution of acute illness, separating the ventilator from the patient may be specially challenging. Before extubation, it is recommended to perform a spontaneous breathing trial (SBT) to evaluate the ability to sustain breathing with minimal or no support.

The way to carry out this step of the weaning process present important variation across regions of the world. Two techniques are preferentially used : the T-piece trial (oxygen supply without positive pressure) and low pressure support ventilation (PSV) from 6 to 10 cmH2O according to the airway humidification device.

The best strategy for successful weaning remains unknown, especially about specific subgroups of respiratory and neurological diseases.

Our aim is to assess which spontaneous breathing trial would best reproduce post-extubation inspiratory effort. We compare T-piece trial, PSV 7 cmH2O without positive end expiratory pressure (PEEP) and PSV 0 cmH2O without PEEP. Five specific profiles are evaluated : chronic obstructive pulmonary disease (COPD), severe brain injury, blunt thoracic trauma, post abdominal surgery and miscellaneous.

The hypothesis is that T-piece trial and PSV 0 CPAP 0 trial are the best for mimic inspiratory effort after extubation. However, we could highlight various results according to different subgroups of ICU patients. The final aim is to determine a personalized wean trial for each.

Inclusion Criteria:

• ICU patient with invasive mechanical ventilation for at least 24 hours
• Physician decision to extubate and all criteria for ventilatory weaning must be present
• Resolution of disease acute phase for which the patient was intubated
• Conscious patient (Richmond Agitation-Sedation Scale (RASS) > 0), no sedation
• Good coughing effort, good swallowing, positive leak test (> 12% of tidal volume (VT))
• No important secretions
• No respiratory acidosis, adequate oxygenation (PaO2 / FiO2 > 150 mmHg and CPAP ≤ 8)
• Adequate pulmonary function (respiratory rate (RR) ≤ 35, negative inspiratory force (NIF) > 20 cmH2O, RR/VT < 105)
• Stable cardiovascular status (heart rate (HR) < 140 bpm, systolic blood pressure > 90 mmHg, no or minimal vasopressors)
• If severe brain injury, the VISAGE score must be ≥ 3 (visual pursuit, good swallowing, GCS > 10)

Exclusion Criteria:

• Obese patients with BMI ≥ 35 kg/m2
• Contraindication for nasogastric tube or esophageal manometric balloon placement
• Refusal of study participation or to pursue the study by the patient, no consent
• Pregnancy or breastfeeding
• Absence of coverage by the French statutory healthcare insurance system