Anemia and Blood Transfusion in Patients with Isolated Traumatic Brain Injury

Transfusion Guidelines in Traumatic Brain Injury: A Systematic Review and Meta-Analysis of the Currently Available Evidence

Our study aims to provide a synthesis of the best available evidence on the hemoglobin (hgb) red blood cell (RBC) transfusion thresholds in adult traumatic brain injury (TBI) patients, as well as describing the risk factors and outcomes associated with RBC transfusion in this population. A systematic review and meta-analysis was conducted using PubMed, Google Scholar, and Web of Science electronic databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to assess articles discussing RBC transfusion thresholds and describe complications secondary to transfusion in adult TBI patients in the perioperative period. Fifteen articles met search criteria and were reviewed for analysis. Compared to non-transfused, TBI patients who received transfusion tended to be primarily male patients with worse Injury Severity Score (ISS) and Glasgow Coma Scale. Further, the meta-analysis corroborated that transfused TBI patients are older (p = 0.04), have worse ISS scores (p = 0.001), receive more units of RBCs (p = 0.02), and have both higher mortality (p < 0.001) and complication rates (p < 0.0001). There were no differences identified in rates of hypertension, diabetes mellitus, and Abbreviated Injury Scale scores. Additionally, whereas many studies support restrictive (hgb <7 g/dL) transfusion thresholds over liberal (hgb <10 g/dL), our meta-analysis revealed no significant difference in mortality between those thresholds (p = 0.79). Current Class B/C level III evidence predominantly recommends against a liberal transfusion threshold of 10 g/dL for TBI patients (Class B/C level III), but our meta-analysis found no difference in survival between groups. There is evidence suggesting that an intermediate threshold between 7 and 9 g/dL, reflecting the physiological oxygen needs of cerebral tissue, may be worth exploring.

The Comorbidities Coma Scale (CoCoS): Psychometric Properties and Clinical Usefulness in Patients With Disorders of Consciousness

Although comorbidities have a well-known impact on the functional recovery of patients with disorders of consciousness, including coma, vegetative state (VS), and minimally conscious state (MCS), a specific tool for their assessment in this challenging group of patients is lacking. For this aim, a multistep process was used to develop and validate the Comorbidities Coma Scale (CoCoS) in a sample of 162 patients with a diagnosis of coma, VS or MCS admitted to four Acute Inpatient Rehabilitation Units. To establish the psychometric properties of the scale, content validity, and internal consistency were investigated through Exploratory Factor Analysis in the whole sample (n = 162). Interrater reliability, assessed by the weighted Cohen's kappa (Kw), and concurrent validity of the scale as compared to the Greenfield Scale, assessed by ρ Spearman's correlation coefficient, were investigated in a subsample of patients (n = 52) within two of the above units. Our findings provided evidence of a good content validity of the scale, with the identification of a 12-factor structure representing the different comorbid dimensions of the target population. Inter-rater reliability was excellent in both the rehabilitation units where the assessment was made [Kw 0.98 (95% CI 0.96–0.99)]. CoCoS total scores correlated significantly with total scores of the Greenfield Scale (ρ = 0.932, 95% CI 0.89–0.96; P < 0.0001) indicating that CoCoS has concurrent validity while being more informative about the specific pattern of comorbidities of these challenging patients. The CoCos is a new tool which standardizes the approach to assessment of comorbid conditions and reliably identifies the category and severity of each comorbidity detected. It may be used for both clinical and research applications.

The effects of anaemia and transfusion on patients with traumatic brain injury: A review

BACKGROUND

Anaemia in traumatic brain injury (TBI) is frequently encountered. Neurosurgical texts continue to recommend transfusion for hematocrit below 30%, despite clear evidence to do so. Transfusion should increase oxygen delivery to the brain, but it may also increase morbidity and mortality.

METHODS

This study reviewed the relevant literature to better understand the risks of anaemia and benefits of correction of anaemia by transfusion.

RESULTS

Of the 21 studies reviewed, eight found that anaemia was harmful to patients with TBI; five found no significant outcome; seven found transfusion was associated with higher rates of morbidity and mortality; two found that transfusion lowered mortality and increased brain tissue oxygen levels; and ten found no correlation between transfusion and outcome. However, the levels of anaemia severity and the outcome measurements varied widely and the majority of outcomes focused on crude measurements rather than detailed functional assessments.

CONCLUSIONS

No division of response based on gender difference or impact of anaemia in the post-hospital treatment setting was observed. A randomized control trial is recommended to determine the impact of anaemia and transfusion on detailed outcome assessment in comparison of transfusion thresholds ranging from ≤ 7 g dL^-1 to ≤ 9 g dL^-1 in patients with moderate-to-severe TBI.