Figure 1.

Boxplot summary of interleukin (IL)-8 levels (upper panel) and boxplot summary of log-transformed IL-8 levels to achieve normal distribution (lower panel). Median levels of IL-8 were 235 pg/ml (range, 10 to 1,836 pg/ml) pre-intubation, 219 pg/ml (range, 10 to 2,115 pg/ml) immediately post-intubation, and 68 pg/ml (range, 10 to 1,552 pg/ml) at 12 to 26 hours post-intubation. The mean levels of IL-8 after log transformation were 5.2 ± 1.8 pg/ml, 5.5 ± 1.5 pg/ml, and 4.5 ± 1.5 pg/ml, respectively. The decrease in IL-8 level at 12 to 26 hours after intubation was statistically significant (p = 0.002, paired t test with Bonferroni correction for multiple comparisons). The horizontal line represents the median, the box encompasses the 25^th to 75^th percentile, and error bars encompass the 10^th to 90^th percentile.