Hypertonic saline (HTS) may have anti-inflammatory properties. We aimed to investigate the effect of pre-hospital HTS on neutrophil to lymphocyte ratio (NLR), a simple marker of systematic inflammation, in patients with severe traumatic brain injury (TBIs). We included 110 adults with blunt TBIs requiring pre-hospital anaesthesia (median age 57.1 years, 67% male). On hospital admission, median NLR was lower in patients who received pre-hospital HTS (7.9 vs 11.9,