The goal of this clinical trial study is to compare dexmedetomidine versus the combination of dexmedetomidine with ketamine in hemodynamic changes and sedative effects in ARDS patients who are in need of mechanical ventilation. The main question[s] it aims to answer are:

• [question 1]: Which dose that get the target in sedation, single and combined drugs?
• [question 2]: In which drug group that hemodynamic did not affect Participants will be patients with ARDS that will be divided into two group the first ont will receive dexmedetomidine 0.5 µg/kg/h mixed with ketamine 0.5 mg/kg/h and the second one will receive dexmedetomidine at 0.5 µg/kg/h infusion only. In both the groups, studied drugs will be titrated to achieve target sedation.

This study will include 60 patients with ARDS who will be admitted to the intensive care unit (ICU) and chest ICU of Banha university hospitals during the period between June 2023 and June 2024.

ARDS will be diagnosed based on the presence of new or worsening symptoms within one week of a known clinical insult; bilateral opacities on anteroposterior chest X-ray that are not due to effusions, nodules or lobar or lung collapse; and hypoxemia, defined as arterial oxygen tension/fraction of inspired oxygen (Pao2/FiO2) < 300 mm Hg and a minimum positive end-expiratory pressure ≥ 5 cm H2O, that is not explained by heart failure or fluid overload.

Patients were divided randomly into two groups. Group A (n = 30); received with starting dose of dexmedetomidine 0.5 µg/kg/h mixed with ketamine 0.5 mg/kg/h and Group B (n = 30); received dexmedetomidine at 0.5 µg/kg/h infusion only. In both the groups, studied drugs will be titrated to achieve target sedation.

All patients will be subjected to the following:

1. Thorough history taking and clinical examination
2. Calculation of acute physiology and chronic health evaluation (APACHE) score at time of ICU admission
3. Sedation score calculation using the Richmond Agitation-Sedation Scale (RASS)
4. ECG, blood pressure monitoring
5. Measurement of plasma C-reactive protein (CRP) level before and after initiation of sedation.
6. Measurement of oxygenation status (Pao2/Fio2) before and at 24, 48, 72, and 120 h after the administration of the sedatives
7. Any adverse effects related to sedation or intubation will be recoded

All data will be tabulated and statistically analyzed

Inclusion Criteria:

• patients with ARDS with the following:

  • Those whose duration of endotracheal intubation was > 120 h
  • those whose ages were 18- 70 years old
  • those with acute physiology and chronic health evaluation (APACHE) II scores > 12 points.

Exclusion Criteria:

• patients with a history of allergy to ketamine or dexmedetomidine
• Pregnant women,
• patients in the early stage of recovery,
• patients with unstable hemodynamics, bradycardia, sinus arrest, or other cardiac arrhythmias