maintaining optimal oxygenation to preserve cerebral function. An obstructed airway
causes carbon dioxide retention and hypoventilation, which can produce cerebral vessel
dilation and increased ICP.
Interventions to ensure an adequate exchange of air are discussed in Chapter 61 and
include the following:
Maintain the unconscious patient in a position that facilitates drainage of oral
secretions, with the head of the bed elevated about 30 degrees to decrease
intracranial venous pressure (Fan, 2004).
Establish effective suctioning procedures (pulmonary secretions produce
coughing and straining, which increase ICP).
Guard against aspiration and respiratory insufficiency.
Closely monitor arterial blood gas values to assess the adequacy of ventilation.
The goal is to keep blood gas values within the normal range to ensure adequate
cerebral blood flow.
Monitor the patient who is receiving mechanical ventilation.
Monitor for pulmonary complications such as acute respiratory distress
syndrome (ARDS) and pneumonia (Bader & Littlejohns, 2004).Monitoring Fluid and Electrolyte Balance
Brain damage can produce metabolic and hormonal dysfunctions. The monitoring of
serum electrolyte levels is important, especially in patients receiving osmotic diuretics,
those with syndrome of inappropriate antidiuretic hormone (SIADH), and those with
posttraumatic diabetes insipidus.
Serial studies of blood and urine electrolytes and osmolality are carried out, because
head injuries may be accompanied by disorders of sodium regulation. Hyponatremia is
common after head injury due to shifts in extracellular fluid, electrolytes, and volume.
Hyperglycemia, for example, can cause an increase in extracellular fluid that lowers
sodium (Hickey, 2003). Hypernatremia may also occur as a result of sodium retention
that may last several days, followed by sodium diuresis. Increasing lethargy, confusion,
and seizures may be due to electrolyte imbalance.
Endocrine function is evaluated by monitoring serum electrolytes, blood glucose
values, and intake and output. Urine is tested regularly for acetone. A record of daily
weights is maintained, especially if the patient has hypothalamic involvement and is at
risk for the development of diabetes insipidus.
Promoting Adequate Nutrition
Head injury results in metabolic changes that increase calorie consumption and
nitrogen excretion. Protein demand increases. Early initiation of nutritional therapy has
been shown to improve outcomes in patients with head injury. Parenteral nutrition via a
central line or enteral feedings administered via a nasogastric or nasojejunal feeding
tube should be started within 48 hours after admission (Bader, Littlejohns & March,
2003). If CSF rhinorrhea occurs, an oral feeding tube should be inserted instead of a
nasal tube.
Laboratory values should be monitored closely in patients receiving parenteral
nutrition. Elevating the head of the bed and aspirating the enteral tube for evidence of
residual feeding before administering additional feedings can help prevent distention,
regurgitation, and aspiration. A continuous-drip infusion or pump may be used to
regulate the feeding. The principles and technique of enteral feedings are discussed in
Chapter 36. Enteral or parenteral feedings are usually continued until the swallowing
reflex returns and the patient can meet caloric requirements orally.