Non-invasive Ventilation and Dexmedetomidine in Critically Ill Adults

Acute respiratory failure (ARF) is a common reason for admission to an intensive care unit (ICU). Non-invasive positive pressure ventilation (NIV) is a life-saving intervention for selected patients with ARF. Compared to endotracheal intubation and invasive mechanical ventilation (IMV), NIV is safer, less invasive, preferred by most patients, and is associated with a reduced ICU length of stay (LOS), less pneumonia and mortality, and lower healthcare costs.

NIV failure can occur, necessitating IMV. Risk factors associated with NIV failure including intolerance, agitation, and delirium. Sedation is a potential solution for NIV intolerance, however the evidence is sparse and the risk of over-sedation resulting in respiratory depression, inability to protect the airway, and inadvertent need for intubation are all large deterrents.

Dexmedetomidine (Dex) is an α2-adrenergic agonist sedative commonly used in IMV that promotes patient wakefulness, has no effect on respiratory drive, has important analgesic properties, and reduces delirium. The investigators hypothesize that Dex, when compared to placebo, reduces NIV failure in hospitalized adults with ARF and agitation or NIV intolerance.

Overall Goal: To determine if Dex, compared to placebo, reduces the risk of NIV failure in patients that admitted to hospital with acute respiratory failure and are intolerant of NIV.

Target Population: 846 patients will be enrolled into the trial if they meet all the following criteria: 1) ≥18 years old; 2) Receiving any NIV modality for ARF of any etiology; 3) Admitted to ICU, PACU, step-down unit (surgical or medical), or emergency department; 4) Presence of one or more of the following: a) Agitation, b) Patient expresses intolerance or requests removal of NIV secondary to self-reported discomfort, anxiety, or claustrophobia, or c) Other reason that the physician feels the patient is intolerant of NIV or agitated not captured above, or feels that the patient will benefit from sedation (all reasons will be recorded).

Methods: The inDEX trial is a pragmatic, international, multi-centred, stratified, randomized, parallel-group, placebo-controlled trial. Patients, investigators, healthcare team, data collectors, outcome assessors, and the statistician will be blinded to trial arms. The trial will maximize external validity by including patients in a range of hospitals across the world. Patients randomized to the experimental arm will receive Dex while those randomized to the control arm will receive placebo.

Assessment: The primary outcome is NIV failure. The investigators define NIV failure as the proportion that require intubation or have died at 28 days.

Inclusion criteria

• Age ≥18 years
• Patient receiving any NIV modality for acute respiratory failure of any etiology
• Admitted to ICU, PACU, step-down unit (surgical or medical), or emergency department(with planned admission to a monitored setting) or equivalent unit where hemodynamics and respiratory status can be monitored, and NIV is permitted; and
• Presence of one or more of the following after optimized NIV treatment:

• Agitation (Defined as a Richmond Agitation and Sedation Scale [RASS] score of ≥+2 or a Riker Sedation-Agitation Scale [SAS] score of ≥5) (Appendix 1 Table 2 and Table 3)
• Patient expresses intolerance or requests removal of NIV secondary to self-reported discomfort, anxiety, or claustrophobia
• Other reason that the physician judges the patient to be intolerant of NIV or agitated, not captured above, or feels that the patient would benefit from titrated sedation for other reasons.

Exclusion criteria

• Absence of a functioning pacemaker with one of the following: a-Persistent bradycardia defined as a heart rate (HR) ≤60bpm; b-Second or third-degree heart block; or c- Tachybrady syndrome
• Persistent hypotension, defined as a mean arterial pressure (MAP) ≤65mmHg despite volume resuscitation and vasopressors
• Imminent need for endotracheal intubation as determined by healthcare team
• Patient's goals of care do not include intubation and IMV
• Patient is not for vasopressors or inotropic support
• Death is deemed imminent and inevitable
• Patient is currently on a dexmedetomidine infusion for a duration of > 12 hours
• Previously enrolled in the inDEX trial
• Acute liver failure with hepatic encephalopathy INR > 3 and/or bilirubin > 300
• Current pregnancy or breast feeding
• Known allergy to dexmedetomidine
• Patients receiving Amphotericin B or Diazepam
• Treating physician does not believe that participation in the trial is in the best interest of the patient (reasons for refusal will be captured)