A Comparison of Two Doses of Mannitol on Brain Relaxation During Supratentorial Brain Tumor Craniotomy
Bibliographic record
Abstract
BACKGROUND: Twenty percent mannitol is widely used to reduce brain bulk and facilitate the surgical approach in intracranial surgery. However, a dose-response relationship has not yet been established. In this study, we compared the effects of 0.7 and 1.4 g·kg(-1) mannitol on brain relaxation during elective supratentorial brain tumor surgery. METHODS: In this prospective, randomized, double-blind study, we enrolled 80 patients undergoing supratentorial craniotomy for tumor resection. Patients were assigned to receive 0.7 g·kg(-1) (group L) or 1.4 g·kg(-1) (group H) of 20% mannitol at surgical incision. Brain relaxation was assessed immediately after opening of the dura on a scale ranging from 1 to 4 (1 = perfectly relaxed, 2 = satisfactorily relaxed, 3 = firm brain, 4 = bulging brain). RESULTS: There was no significant difference between the 2 groups regarding age, sex, body mass index, and brain tumor localization or size. In group L 52.5% of patients and in group H 77.5% of patients presented a midline shift (P = 0.03). The median scores of brain relaxation (interquantile range) were 2.0 (1.75-3) and 2.0 (1-3) (P = 0.16 for patients in group L and H, respectively). We then used a proportional odds model to adjust for this unbalanced distribution and to assess the group effect (low-dose versus high-dose mannitol) on brain relaxation scores. When adjusted for the presence of midline shift, the use of a higher dose of mannitol resulted in an odds ratio of 2.5 (P = 0.03). This indicates that, considering the effect of a midline shift, the odds of having a 1-level improvement in relaxation score in patients who received a higher dose of mannitol (group H) was 2.5 times as large as the odds for the low-dose group. The odds ratio of 0.29 (P = 0.007) for the midline shift indicates that its occurrence was associated with a higher probability of a lower relaxation score, on average. CONCLUSION: In this study, we show that 1.4 g·kg(-1) of 20% mannitol results in equivalent brain relaxation scores as 0.7 g·kg(-1) in patients undergoing craniotomy for supratentorial brain tumor. When corrected for the presence of midline shift, this study reveals that patients in the high-dose group had significantly more chances of obtaining a better relaxation score compared with the lower-dose group.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".