Table 3. Cytokine levels in bronchoalveolar lavage (BAL) of mechanically ventilated trauma patients.

	Culture Positive	RTF	Culture Negative
IFN-Gamma	17.45 ± 3.46	15.84 ± 5.03	1.12 ± 0.73*
IL-17F	22.03 ± 3.22	21.84 ± 7.96	4.22 ± 2.70*
IL-1B	1190.67 ± 340.1	349.69 ± 104.1	46.27 ± 37.13*
IL-31	6.11 ± 1.30	5.88 ± 1.74	0.71 ± 0.46*
TNF-a	28.49 ± 9.49	42.104 ±22.2	0.8 ± 0.0.32*

Supernatants from raw BALs were measured by multiplex cytokine assay. Samples were divided into three groups based on the results from the clinical pathology lab: culture-negative, culture-positive, and respiratory tract flora (RTF). All samples were run in triplicate. Values are given as pg/ml ± standard error of the mean. Culture-negative and RTF samples were compared against culture-positive samples using Kruskal-Wallis test (overall P = 0.0006).

Dunn’s post-hoc multiple comparison test was utilized to adjust P-values to determine statistical significance at *P < 0.05.

The cytokine levels between culture positive and culture negative samples were statistically different (adjusted P = 0.0016). Cytokine levels between respiratory tract flora and culture positive (adjusted P = 0.1957) or culture negative (P = 0.2526) samples.