Early Initiation of Sub-Anesthetic Ketamine Infusion in Adults with Vaso-Occlusive Crises Is Associated with Greater Reduction in Sickle Cell Pain Intensity: A Single Center's Experience.

Abstract

Recurrent, severely painful episodes, known as vaso-occlusive crises (VOCs) are the hallmark of sickle cell disease (SCD) and the primary reason for hospitalization. Opioids have been the gold standard for VOC treatment without significant improvement pain outcomes. To aid analgesia and combat opioid related adverse effects (ORAEs), some SCD clinicians have trialed infusions of sub-anesthetic ketamine along with opioids to treat VOCs. In this retrospective analysis, we compared adult SCD patients who received early vs late adjunctive sub-anesthetic ketamine infusions for VOCs. We identified adult SCD patients (age 18-50 years) who presented to Duke University with a VOC and received sub-anesthetic ketamine infusions from July 2015 to June 2019. We assessed both daily opioid consumption (measured as oral morphine milligram equivalents (MME)) and self-reported 0-10 numeric pain ratings (NPR) at 1, 2, and 3 days after infusion initiation, as well as 1 day after discontinuation. A total of 56 patients were identified with a median age of 30 years. Compared to late administration, early infusion of sub-anesthetic ketamine was associated with a 24.5% (P = .0003) and 25.9% (P = .0006) reduction, respectively, in median NPR at 1 day and 2 days after infusion initiation but did not persist at 3 days following initiation of the infusion. A statistically significant reduction in MME was not observed. In a nonrandomized study of sickle cell patients with VOCs, early sub-anesthetic ketamine infusion led to greater reduction in subjective pain intensity than late initiation of the infusion. Randomized studies should further explore whether early vs late ketamine infusion improves management of acute SCD pain.