Ketorolac at Lower Doses for Analgesic Pain Control in ICU: A Pilot Feasibility Study

Inclusion Criteria: * Age \> 18 years * Admission to intensive care unit (ICU) * Participants with pain (Critical Care Pain Observation Tool \[CPOT\] \> 1 and/or self-report pains score \>1 on visual analogue scale \[VAS\] or numerical rating scale \[NRS\]) Exclusion Criteria: * Serum Cr \> 100 mmol/L for females, and \>130 mmol/L for males * Ongoing ACEi (angiotensin converting enzyme inhibitor)/ARB (angiotensin receptor blocker) use in ICU * Known hyperkalemia \> 5.5 * Pre-existing chronic kidney disease (CKD Stage \> 3), defined by a serum Cr \> 100 mmol/L for females, and \>130 mmol/L for males (at the time of screening, based on pre-hospital stable outpatient baseline values) * New acute kidney injury KDIGO Stage \> 2 (increased more than \> 2-to-3 times in serum creatinine above baseline AND/OR \<0.5mL/kg/hour urine output for \>12 hours) * Pre-existing gastrointestinal bleeding (within 12 weeks of hospital admission, requiring hospitalization or medical evaluation), new peptic ulcer disease, esophagitis, esophageal varices within the last 3 months * Active gastric / duodenal / peptic ulcer, active GI bleeding * Prior contraindications/allergies to NSAIDS or stress ulcer prophylaxis, specifically if a participant has had an anaphylactic reaction (asthma or urticaria) or non-anaphylactic asthma reaction to NSAIDs or any stress ulcer prophylaxis, e.g. proton pump inhibitor, histamine-2-blockers, etc. (e.g. proton pump inhibitor, histamine-2-blockers, etc.) * Complete or partial syndrome of ASA-intolerance (e.g. rhinosinusitis, urticaria/angioedema, nasal polyps, asthma) * Participants who are not receiving stress ulcer prophylaxis (e.g. proton pump inhibitor, histamine-2-blockers, etc.) while in ICU * Any active bleeding (requiring any blood products or adjunctive coagulation agents, any output of blood \>100 mL/hr, e.g. chest tube drainage, abdominal cavity drain, etc.) * Currently receiving NSAID(s) for another indication * Inflammatory bowel disease (e.g. participants with prior diagnosis of Crohn's disease or ulcerative colitis) * Receiving probenecid, oxpentifylline or pentoxifylline * Active ischemic heart disease (acute myocardial infarction, acute coronary syndrome during current hospital admission) * Moderate-severe uncontrolled heart failure (New York Heart Association: Class II-IV) * Moderate to severe liver impairment or active liver disease (Operational definition: participants with prior history of Child-Pugh class B (moderate) or C (severe) liver cirrhosis, OR Model for End-Stage Liver Disease-Sodium (MELD-Na) score \>25, OR active acute liver failure: severe acute liver injury with encephalopathy and impaired synthetic function International Normalized Ratio (INR) \>1.5 with or without pre-existing liver disease) * Active cerebrovascular bleeding or stroke (cerebrovascular accident, transient ischemic attacks and/or amaurosis fugax, e.g. participants with active stroke symptoms within current hospital admission) * Cerebrovascular bleeding or other bleeding disorders * Coagulation disorders, post-operative patients with high haemorrhagic risk or incomplete haemostasis in patients with suspected or confirmed cerebrovascular bleeding * Neuraxial (epidural or intrathecal) administration of ketorolac tromethamine injection due to its alcohol content * Rhabdomyolysis (creatinine kinase \>5000 U/L) * Recent transplant (during same hospital admission, e.g., heart, lung, kidney, liver, etc.) * Known allergy to ketorolac or other NSAIDs * Participants expected to stay in ICU \< 48 hours * In the opinion of the attending physician, expected death or withdrawal of life-sustaining treatments within 48 hours * Participant is known to be pregnant and/or breastfeeding * Most responsible physician, participant, or substitute decision maker declines study participation (and reason)