MN, a 28-year old female arrives via EMS to the emergency room. After gathering a history from the patient’s family members, you learn MN fell down the stairs and struck her head. Upon examination it is determined that MN is suffering from a traumatic brain injury with significantly elevated intracranial pressure.  MN’s laboratory findings and vitals are listed below: 

Labs/Vitals:

Ht: 5’9 ft

Wt: 140 lbs

BP: 80/50 mmHg

HR: 121 BPM

Temp: 100.6 F

Na: 132 mEq/L (135-145 mEq/L)

Cl: 90 mEq/L (95-105 mEq/L)

K: 3.5 mEq/L (3.5-5 mEq/L)

Ca: 8.5 mg/dL (8.5-10.5 mg/dL)

Mg: 1.7 mg/dL (1.7-2.2 mg/dL)

Serum lactate 3.0 mmol/L (0.5-2.2 mmol/L)

What therapeutic resuscitation option is most appropriate for the acute management of MN at this time?

A. Lactated Ringer’s solution

B. 3% NaCl solution

C. Dextrose solution

D. 5% Albumin

Answer with rationale:

TBI injuries are common and can occur in patients at any age. These are typically from an acute event, such as blunt force trauma. Signs and symptoms can be mild such as headache or dizziness or severe with seizures. 

Hypertonic saline is the preferred fluid for traumatic brain injury (TBI) for patients with elevated intracranial pressure (ICP) because it reduces cerebral edema while maintaining cerebral perfusion. The high osmolarity pulls water out of the swollen brain cells and into the intravascular space, lowering ICP without worsening brain swelling. Unlike hypotonic or dextrose-containing fluids, hypertonic saline does not increase the water content of the brain. Clinical evidence supports its safety and efficacy in TBI patients making it superior option compared to crystalloids for managing elevated ICP.

Answer A is incorrect. During a traumatic brain injury lactate levels may increase due to a decrease in available oxygen and the conversion from aerobic metabolism to anaerobic. In this case, the patient’s lactate levels are currently out of range and elevated. Prescribing lactated ringers would further elevate the patient’s lactate level and would not be recommended. Keep in mind that this solution also contains potassium at a concentration of 4 meq/L which could be problematic in patients with significant hyperkalemia. 

Answer B is correct. Hypertonic solutions have a higher osmolarity to aid in removing excess water from the brain. This allows for a reduction in swelling and an improvement in cerebral perfusion. It is important to avoid rapid correction with hypertonic solution to prevent cell shrinkage and damage to the myelin sheath. Hypertonic saline can also be used to manage significant hyponatremia with clinical symptoms (e.g. neurologic). 

Answer C is incorrect. Dextrose is not a suitable fluid option to be used for resuscitation. The use of a hypotonic fluid such as dextrose can cause an increase in intracranial pressure and further exacerbate cerebral edema associated with traumatic brain injuries.

Answer D is incorrect. Albumin is not recommended in traumatic brain injuries. Not only can it cause an increase oncotic pressure but also exacerbate cerebral edema and intracranial pressure. The use of albumin in traumatic brain injuries is associated with an increased mortality rate in some studies.  

Naplex Domains Covered:

1.C.5 - Drug concentrations, ratio strengths, osmolarity, or osmolality

2.A.2 – Indications, usage

2.A.5 - Safety and effectiveness (eg, laboratory parameters, vital signs)

3.C.2 - Appropriateness of therapy (eg, medications, immunizations, non-drug therapy, dosing, contraindications, warnings, evidence-based decision making)