TBI Calculator
The Traumatic Brain Injury Calculator
The traumatic brain injury calculator is a useful, but generalized model that is used to assess traumatic brain injuries. It is used in acute, sub-acute and post-acute settings. The purpose of it is to help establish the prognosis for clients who have sustained head injuries. More specifically, it is a prognostic model that may be used as an aid to estimate mortality at approximately 14 days through six months post TBI. It can help to calculate other outcomes, including:
• Persistent vegetative state;
• Severe disability;
• Lower grade disability: expected dependency for activities of daily living (ADLs);
• Upper grade disability: expected ability to care for oneself, but unable to work;
• Moderate disability: refers to the expected ability to travel independently and to work in a sheltered environment;
• Upper grade disability: the individual is expected to be able to work in a reduced capacity, but there are deficits in speech, memory and personality change;
• Good recovery: There are sub-categories to this level. At the lower grade, the individual will be expected to participate socially. At the upper grade, there is an expectation of the resumption of normal life subject to relatively minor neurological or psychological deficits[1].
Among the key predictors in these types of calculators is the Glasgow Coma Scale (GCS) if it is administered within eight hours of the injury. The average GCS for adults that is used by the calculators in making the predictions, is a score of 14 or less. Other predictors are age of the injured person, pupil reactivity and the existence of major extracranial injury. This is referred to as the “basic” model. There also exists a “CT” model that, in addition to the foregoing predictors, includes computed tomography[2]. The Extended Glasgow Scale is sometimes used to predict outcomes as well, the categories of which are described above[3].
There are other, broad, categories that are considered by the models. These include “clinical” categories that encompass the following predictors:
• Age: People who sustained traumatic brain injuries when over age 40 usually experience worse outcomes in the sense that their recovery is less complete as compared to their pre-injury physical and mental status;
• Hypotension (low blood pressure): Although one might think that low blood pressure is always a good thing, for many people, low blood pressure can cause symptoms of dizziness and fainting. In severe cases, low blood pressure can be life threatening;
• Hypoxia (low oxygen levels);
• Pupil size and reaction to light;
• Nature and extent of intracranial injuries;
• Comorbidities (one or more other conditions or diseases that exist in conjunction with the main condition);
• Another factor affecting the utility of these calculators is the quality of care administered to the injured person. In turn, this correlates with the country in which the injury occurred, (where the person is located) and where the care was delivered. These are all variables considered by the calculators and in the predicted outcome for the injured person[4]. The models allow for the selection of specific countries, but in general, the estimates are based on two sets of alternative models: high income countries and middle to low income countries
Another predictor for the modeling is “radiological.” This is often disclosed by a CT scan of the brain. Ominous results include an abnormal condition or obliteration of the third ventricle or the basal cisterns, or evidence of a “midline shift.”
• The absence of the basal cisterns is a strong predictor of 6-month mortality. Damage to the third ventricle, as a major pathway for cerebrospinal fluid to and from the brain, may alter the flow and result in abnormal intracranial pressure;
• Midline shift. This is a shift of the brain in either direction beyond its center line. It is potentially troublesome because it may be indicative of a distortion of the brain stem or high intracranial pressure. It may evidence itself by abnormal posture, abnormal pupillary reaction.
NeuLife, in Mount Dora, Florida, is a fully accessible residential post-acute program providing superior care and specialized rehabilitation to individuals diagnosed with traumatic brain injury (TBI), spinal cord injury (SCI), traumatic amputations and other catastrophic injuries.
2725 Robie Avenue
Mount Dora, Florida 32757
Call: 800-626-3878
Email: [email protected]
Visit: NeuLifeRehab.com
[1] http://lifeinthefastlane.com/education/ccc/traumatic-brain-injury-tbi-prognosis/
[2] Predicting outcome after traumatic brain injury: practical prognostic models based on large cohort of international patients British Medical Journal, http://www.bml.com/content/336/7641/425
[3] Sander, A. (2002). The Extended Glasgow Outcome Scale. The Center for Outcome Measurement in Brain Injury. http://www.tbims.org/combi/gose
[4] hppp://www.trialscoordinatingcentre.lstm.ac.uk/Risk%20calculator/index.html
