A Study of Ketamine Infusions to Treat Clinically-depressed ICU Patients

Inclusion Criteria: Has been in the Mayo Clinic Florida ICU for the past 1 week. PHQ-9 score of 10 or higher. One of the following diagnoses: acute myocardial infarction; acute renal failure; chronic obstructive pulmonary disease (COPD); congestive heart failure; end-stage liver disease; patients requiring intra-aortic balloon pump (IABP) therapy or continuous renal replacement therapy (CRRT); post-bone marrow transplant; acute Hypoxemic Respiratory Failure; acute or chronic hypoxemic respiratory failure; pre- or post- lung, liver or heart transplant or surgical overflows (such as abdominal aortic aneurysm, thoracotomy or tracheostomy). Exclusion Criteria: Poor vital sign stability hypoxia: O2 < 95%, hypotension: SBP < 90 hypertension: SBP > 180. Heart rate: < 50 or > 120, or Respiratory Rate: < 10 or > 30. Altered mental status. Patient is unwilling to participate or provide informed consent. Any allergy to ketamine or diphenhydramine. Patient is female of child-bearing age and unwilling to provide urine or blood for HCG analysis. Pregnant or breastfeeding. Presence of intracranial mass or vascular lesion. Presence of a history of psychosis or hallucinations (as assessed by electronic chart review). Weight greater than 115 kg or less than 45kg. History of increased intracranial pressure/hypertensive hydrocephalus or increased intraocular pressure. Patient is acutely psychotic. Provider feels that patient currently or likely will require chemical and/or physical restraints. History of prolonged QT-interval. Current treatment includes any medication known to affect the N-methyl-D-aspartate receptor system (e.g., lamotrigine, acamprosate, memantine, riluzole, or lithium). Patient in withdrawal from substance abuse or who have used hallucinogens (including cannabis) in the last month for any indication, as determined by the clinical interview and urine drug screening.