Mayuki Aibiki, Kensuke Umakoshi, Saori Ohtsubo, Satoshi Kikuchi, Hironori Matsumoto, Muneaki Ohshita, Soichi Maekawa and Takashi Nishiyama
Objectives: We studied retrospectively to examine differences in the occurrence rate of pneumonia and the
time-course changes in pulmonary oxygenation between hypothermic and normothermic therapies with or without
dexamethasone (D) administration in patients with traumatic brain injury (TBI).
Design: A retrospective observational study.
Setting: Two university hospitals.
Subjects and Methods: In consecutive TBI patients (GCS ≤ 8) treated with hypothermic (N=23, 32-33°C) or
normothermic (N=16, 36-37.5°C) therapy, the occurrence rate of pneumonia, PaO2/FIO2 (P/F) ratios and C-reactive
protein (CRP) levels were examined. The comparisons were made among hypothermic and normothermic groups
with or without D administration. In several patients in both groups, neutrophil functions were examined. Data were
analyzed with ANOVA followed by Sheffe’s F-test, Mann-Whitney U-test, Kruskal-Wallis tests or chi-squared test
(p<0.05) as appropriate.
Results: The occurrence rate of pneumonia in a hypothermic group with D administration was significantly
lower than in a hypothermic group without D. In the hypothermic group without D treatment, CRP elevation during
the rewarming phase occurred, which was followed by more severe P/F ratio deteriorations as compared to the
hypothermic group given D. Neutrophil phagocytic functions in hypothermic patients without D were activated
around 35°C, which were followed by marked decreases in pulmonary oxygen. In contrast, phagocytic function in a
hypothermic patient receiving D was depressed, but without P/F ratios below 280.
Conclusion: This study poses hypotheses that neutrophils play a role in the pulmonary oxygenation impairment in
hypothermic therapy for TBI patients, and that dexamethasone improves the pulmonary complications in therapeutic
hypothermia.