Therapeutic Hypothermia with Rapid Thin Liquid Convection Is Safe and Feasible in Acute Stroke Patients: The SISCO Pilot Study

Justin A. Salerian¹Robert B. Schock^2*Clemens M. Schirmer³Souvik Sen⁴Sheryl Martin-Schild⁵Oded Goren³Douglas F, Kupas³Robert J. Freedman²Aimee Aysenne¹

• ¹School of Medicine, Tulane University, New Orleans, Louisiana, United States
• ²Life Recovery Systems, Kinnelon, United States
• ³Geisinger Medical Center, Danville, Pennsylvania, United States
• ⁴University of South Carolina, Columbia, Missouri, United States
• ⁵Dr. Brain, Inc., Metairie, Louisiana, United States

Background: Laboratory studies have shown that rapid therapeutic hypothermia (TH) of <34°C can reduce stroke infarct volume by over 50%. The EuroHyp-1 and ICTUS 2/3 trials found no benefits in the slow cooling of ischemic stroke patients, while extensive shivering was observed. More powerful cooling methods are required to improve outcomes. Methods: In a feasibility study approved to include up to 30 patients, the ThermoSuit® System (TSS) was used to cool sedated ischemic stroke patients to 32-34°C. Patients were cooled after reperfusion, and TH was maintained for 24 hours. Cooling speeds, adverse events, and neurological outcomes (including Modified Rankin Score (mRS) at 90 days) were documented. Results: The trial was terminated after enrolling 14 subjects from 3 sites after meeting the study feasibility criteria. Ten subjects qualified for outcomes analysis. All cooled patients reached the 34°C target with a median time of 40 minutes. Patients cooled under this protocol showed no increased harm and trends for improved neurological outcomes compared to previously published studies. A pneumonia rate of 23% (3/13) was comparable to prior studies in which stroke patients were cooled. Brief shivering occurred in most patients but was limited to 5.4% of the time while in the hypothermic temperature range. Patients cooled per the SISCO protocol had a rate of acceptable outcomes (mRS≤3) of 90%. In intention-to-treat analysis, 82% of patients had acceptable outcomes. Discussion: The TSS is a feasible tool to achieve TH in ischemic stroke patients. This non-invasive cooling technique allows swift cooling of patients to ≤ 34°C with little shivering and no apparent safety issues. Further studies are warranted to prove this rapid cooling method is cytoprotective in stroke patients, as evidenced by improved odds of functional independence.