DRG Category: 84
Mean LOS: 2.6 days
Description: Medical: Traumatic Stupor and Coma > 1 Hour Without Complication or Comorbidity or Major Complication or Comorbidity
DRG Category: 86
Mean LOS: 4.0 days
Description: Medical: Traumatic Stupor and Coma < 1 Hour With Complication or Comorbidity
DRG Category: 955
Mean LOS: 11.0 days
Description: Surgical: Craniotomy for Multiple Significant Trauma
A diffuse axonal injury (DAI), the most severe of all traumatic brain injuries (TBIs), occurs when nerve axons are stretched, sheared, or even torn apart during trauma. A DIA generally consists of tears in the white matter of the brain that measure 1 to 15 mm in size. The severity and outcome of a DAI depend on the extent and degree of damage to brain structures and can be classified as mild, moderate, or severe DAI. All types of DAI are associated with an immediate and prolonged (> 6 hr) coma. Mild DAI is associated with a coma that lasts from 6 to 24 hours and has a 15% mortality rate; 80% of patients experience a good recovery. Moderate DAI, the most common form, is associated with a coma that lasts 24 hours or more, decerebration (extension posturing), and decortication (flexion posturing). Approximately 25% of patients with moderate DAI die. Severe DAI, which has a mortality rate of 50%, occurs when there is an extensive disruption of axons in the white matter of the central nervous system. People who emerge from coma usually do so in the first 3 months after injury, but many of those who live remain in a persistent vegetative state. DAI is more likely to cause morbidity than other types of TBI.
The pathophysiology of DAI is based on a model of shear injury; the TBI occurs because of sudden acceleration-deceleration impact, which can produce rotational forces that affect the brain. The injury to tissue is greatest in areas where the density difference in the brain is greatest, so most DAI lesions occur at the junction of gray and white matter. Injury results in edema and axonal tearing, and the severity of injury depends on the distance from the center of rotation, the arc of rotation, and the duration and intensity of the force. Complications include posttraumatic coma, disability, persistent neurovegetative state, and death.
The predominant causes of injuries that lead to DAI are high-speed motor vehicle crashes (MVCs), motorcycle crashes, and automobile-pedestrian crashes. The severity of the MVC is correlated with the severity of DAI. While there is some uncertainty, experts suggest that DAIs can result from explosion injuries and incendiary weapons.
No clear genetic contributions to susceptibility have been defined.
DAIs can be experienced by patients of all ages and both sexes, but males are affected at higher rates than females. Trauma is the leading cause of death between the ages of 1 and 44 years, and high-speed MVCs are the most common cause of DAI followed by sports injuries. In children from birth to 4 years of age, assault is the most common cause of TBI. In people recovering from DAIs, younger age is associated with a more favorable recovery.
In recent years, Black persons have been killed in traffic crashes at a rate almost 25% higher than White persons (National Highway Traffic Safety Administration [NHTSA], 2021). However, Native American persons have the highest rate of MVC injury in the United States, more than twice the rate of Black persons (NHTSA, 2021). Experts have noted that Black and Native American communities tend to be crisscrossed by more dangerous roads than other locations, placing people from those communities at risk for injury. Healthy People 2020 reports that non-Hispanic Black persons have the highest overall injury death rate in the United States (79.9 injury deaths per 100,000 people), followed by non-Hispanic White persons (79.2), Native American persons (78.2), Hispanic persons (45.5), and Asian/Pacific Islander persons (25.6). Stark disparities exist with the incidence, management, and rehabilitation of TBI and DAI. The Centers for Disease Control and Prevention (CDC) report that Native American children and adults have the highest TBI-related hospitalizations and deaths in the United States. Important health disparities exist in treatment, follow-up, and rehabilitation of TBI. Non-Hispanic Black and Hispanic patients are less likely to receive follow-up care and rehabilitation following TBI and more likely to have poor psychosocial, functional, and employment-related outcomes as compared to non-Hispanic White patients (CDC, 2021).
The CDC reports that in the 20 years since the year 2000, more than 400,000 U.S. service members were diagnosed with TBI, including active military service members and Veterans. Approximately 80% of these injuries occurred when the service members were not deployed. These injuries may result in ongoing symptoms, posttraumatic distress syndrome, and suicidal thoughts. People in correctional or detention facilities, people who experience homelessness, and survivors of intimate partner violence may have long-term consequences from TBI. People with lower incomes and those without health insurance have less access to TBI care, are less likely to receive surgical procedures and cranial monitoring when indicated, are less likely to receive rehabilitation, and are more likely to die in the hospital. Recent work has shown that rural populations have injury mortality rates that are more than twice as high as urban rates. Many factors contribute to these health disparities, including the risk of traffic injury in narrow rural roads, the lack of graded curves and lighted traffic signals on rural highways, and the distance from major trauma centers. Many of the most dangerous occupations, such as mining and agriculture, are found in rural areas and can result in injury, disability, and death. People living in rural areas who experience a TBI have more time to travel to get emergency care, less access to high-level trauma care, and more difficulty accessing TBI services. Sexual and gender minority persons have high risk for dating and interpersonal violence, violence related to bullying, and intentional and unintentional injury and therefore are at risk for TBI (Healthy People 2020).
DAI is a diagnosis made primarily in Western countries by radiography. Few epidemiological data are available internationally or in developing countries. However, developing countries have a growing health crisis as MVCs increase, and violence/war is an ongoing, serious issue in many parts of the developing and developed world.
PLANNING AND IMPLEMENTATION
Collaborative
Most patients with severe injury will require endotracheal intubation and mechanical ventilation to ensure oxygenation and ventilation and to decrease the risk of pulmonary aspiration. A Pao2 greater than 100 mm Hg and a Paco2 between 28 and 33 mm Hg may be maintained to decrease cerebral blood flow and intracranial swelling. Fluid administration guided by intracranial pressure (ICP), cerebral perfusion pressure (CPP; calculated number CPP = MAP - ICP; MAP is mean arterial pressure), arterial blood pressure, and saturation of mixed venous blood (SvO2) is critical.
ICP monitoring may be used in patients with severe head injuries who have a high probability of developing intracranial hypertension. Some physicians use a GCS score of less than 7 as an indicator for monitoring ICP. The goal of this monitoring is to maintain the ICP at less than 10 mm Hg and the CPP at greater than 80 mm Hg. Management of intracranial hypertension can also be done by draining cerebrospinal fluid through a ventriculostomy.
Some patients may have episodes of agitation and pain, which can increase ICP. Sedatives and analgesics can be administered to control intermittent increases in ICP, with a resulting decrease in CPP. Additionally, some patients with severe head injuries may require chemical paralysis to improve oxygenation and ventilation. Other complications are also managed pharmacologically, such as seizures (by anticonvulsants), increased ICP (by barbiturate coma), infection (by antibiotics), and intracranial hypertension (by diuretics). While corticosteroids have been used to reduce swelling and improve outcomes after DAI, several randomized controlled trials have shown that they are not beneficial in DAI.
| Medication or Drug Class | Dosage | Description | Rationale |
|---|
| Sedatives and chemical paralytics | Varies by drug | Short-acting: Midazolam (Versed); propofol (Diprivan) | Control intermittent increases in ICP with a resultant decrease in CPP; improve oxygenation and ventilation |
| Analgesics | Varies by drug | Fentanyl (Sublimaze) | Control intermittent increases in ICP with a resultant decrease in CPP |
Independent
The highest priority is to maintain a patent airway, appropriate ventilation and oxygenation, and adequate circulation. Make sure the patient's endotracheal tube is anchored well. If the patient is at risk for self-extubation, maintain the patient in soft restraints. Note the lip level of the endotracheal tube to determine if tube movement occurs. Notify the physician if the patient's Pao2 drops below 80 mm Hg, if Paco2 exceeds 40 mm Hg, or if severe hypocapnia (Paco2< 25 mm Hg) occurs.
Serial assessments of the patient's neurological responses are of the highest importance. When a patient's assessment changes, timely notification to the trauma surgeon or neurosurgeon can save a patient's life. The patient with DAI is dependent on nurses and therapists for maintaining muscle tone, joint function, bowel and bladder function, and skin integrity. Consult the rehabilitation department early in the hospitalization for evaluation and treatment. Frequent turning, positioning, and use of a pressure-release mattress help prevent alterations in skin integrity. Keep skin pressure points clean and dry.
Provide the family with educational tools about head injuries. Referrals to clinical nurse specialists, pastoral care staff, and social workers are helpful in developing strategies to increase education and support. Establish a visiting schedule that meets the needs of the patient and family while providing adequate time for patient care and rest. The mortality of patients with diffuse axonal injury ranges from 15% to 51%, with a wide variation in the level of cognitive functioning that the patient can reach through intensive rehabilitation. Education and support for the family are critical in assisting them in coping with the severity of this injury.
Evidence-Based Practice and Health Policy
Lohani, S., Bhandari, S., Ranabhat, K., & Agrawal, P. (2020). Does diffuse axonal injury MRI grade really correlate with functional outcome? World Neurosurgery, 135, e424–e426.
- The authors examined the association of DAI grades with the extended Glasgow Outcome Scale (GOSE). The authors performed a medical record review of a cohort of patients discharged with the diagnosis of DAI with a focus on GCS, DAI grade, length of hospital stay, and occurrence of posttraumatic seizures. They contacted patients 6 months after treatment to assess their GOSE.
- Nine patients (23%) had posttraumatic seizures. Mean GCS at admission was 9.67; mean length of hospital stay was 24.12 days. Mean GOSE after 6 months was 6.10. Mortality rate was 12.5%. Patients with low mean GCS had significant unfavorable outcomes, but higher DAI grades were not associated with unfavorable outcomes. The authors concluded that mean GCS at presentation is a better predictor of outcome after DAI than its grade.