01-08-2011 | Original Article
The Effect of Decompressive Hemicraniectomy on Brain Temperature After Severe Brain Injury
Published in: Neurocritical Care | Issue 1/2011
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Background
Animal studies have shown that even a small temperature elevation of 1°C can cause detrimental effects after brain injury. Since the skull acts as a potential thermal insulator, we hypothesized that decompressive hemicraniectomy facilitates surface cooling and lowers brain temperature.
Methods
Forty-eight patients with severe brain injury (TBI = 38, ICH = 10) with continuous brain temperature monitoring were retrospectively studied and grouped into “hemicraniectomy” (n = 20) or “no hemicraniectomy” (n = 28) group. The paired measurements of core body (T
Core) and brain (T
Br) temperature were recorded at 1-min intervals over 12 ± 7 days. As a surrogate measure for the extent of surface heat loss from the brain, ∆T
Core−Br was calculated as the difference between T
Core and T
Br with each recording. In order to accommodate within-patient temperature correlations, mixed-model regression was used to assess the differences in ∆T
Core−Br between those with and without hemicraniectomy, adjusted for core body temperature and diagnosis.
Results
A total of 295,883 temperature data pairs were collected (median [IQR] per patient: 5047 [3125–8457]). Baseline characteristics were similar for age, sex, diagnosis, incidence of sepsis, Glasgow Coma Scale score, ICU mortality, and ICU length of stay between the two groups. The mean difference in ∆T
Core−Br was 1.29 ± 0.87°C for patients with and 0.80 ± 0.86°C for patients without hemicraniectomy (P < 0.0001). In mixed-model regression, accounting for temperature correlations within patients, hemicraniectomy and higher T
Core were associated with greater ∆T
Core−Br (hemicraniectomy: estimated effect = 0.60, P = 0.003; T
Core: estimated effect = 0.21, P < 0.0001).
Conclusions
Hemicraniectomy is associated with modestly but significantly lower brain temperature relative to core body temperature.