Dependence of rate of brain cooling on nasal airflow rate. (a) In 1.8-kg piglets, brain temperature (averaged across 5 regions) fell more rapidly by increasing the airflow rate from 4 L/min (n = 6) to 8 L/min (n = 6) and from 8 L/min to 16 L/min (n = 6); *P < 0.05 from 8 L/min, †P < 0.05 from 16 L/min. (b) In 4-kg piglets, brain temperature fell more rapidly with airflow rates of 32 L/min (n = 8) or 48 L/min (n = 6) than with 16 L/min (n = 6); *P < 0.05 from 32 and 48 L/min and (c) In 15-kg piglets, airflow had no differential effect between 16, 32 and 48 L/min (n = 7 per group). Values are means ± SD; data analyzed with two-way ANOVA and Holm-Sidak post hoc comparisons.