Selective cerebral hypothermia induced via hypothermic retrograde jugular vein saline flush in a porcine model

Objectives: Multiple methods of selective brain cooling have been used to prevent cerebral ischemia secondary to trauma and pathological or iatrogenic cerebral blood flow restriction. In this study, we tested the efficacy of hypothermic retrograde jugular vein flush (HRJVF) in eliciting selective brain hypothermia in a porcine model. Methods: Twelve swine were divided into two groups: retrograde jugular vein infusion (RJVI) with cold saline (4°C RJVI, n = 6) and with room temperature saline (24°C RJVI, n = 6). For 90 minutes, the following parameters were measured: brain parenchymal temperature, rectal temperature, intracranial pressure (ICP), mean arterial pressure, and heart rate (HR). Results: Swine receiving 4°C RJVI experienced a drop in mean brain parenchymal temperature of 1.1 ± 0.1°C, compared to 0.1 ± 0.1°C in swine receiving 24°C RJVI. At 90 minutes, mean brain parenchymal temperature in the 4°C RJVI treatment group was 35.5 ± 0.2°C, as compared to 37.1 ± 0.2°C in the 24°C RJVI treatment group (P <0.001). In the 4°C RJVI group, the brain-systemic temperature gradient peaked 10 minutes after initiation of cooling and remained significantly different when comparing the two experimental groups (P <0.001) throughout the duration of the 90 minutes experiment. Of note, ICP, mean arterial pressure, and HR remained constant without any significant changes or differences between treatment groups. Discussion: These results suggest that HRJVF is an effective method for selective brain hypothermia in a large animal model. Clinical application may prove effective in delaying neural ischemia.