Page 1179 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

816 PART 6: Neurologic Disorders

involvement of the dominant or nondominant hemisphere, the require- bifrontotemporoparietal craniectomy with durotomy in adults (<60
ment for a unilateral or bilateral procedure, and the necessity for dural years old) with severe TBI (GCS 3-8) and refractory intracranial
closure or the use of a dural patch to significantly expand the intracra- hypertension (defined in this study as elevation of ICP >20 mm Hg for
nial compartment. Diffuse cerebral edema usually requires bifrontal >15 minutes). The study showed significant reduction in ICP, fewer
168
craniectomies in order to sufficiently control ICP. Unfortunately, there interventions for increased ICP, and fewer days in the ICU for the
164
is currently little consensus among neurosurgeons with respect to the surgical group; however, clinical outcome as assessed by the Extended
indications, usefulness, and techniques of decompression. The crani- Glasgow Outcome Score was worse in the surgical group. Patients
ectomy must be large enough to relieve brain swelling and control ICP in the decompression group had an odds ratio for a worse score of
as well as to reduce the risks of herniation through the craniectomy site 1.84 (95% CI 1.0-3.24; p = 0.03) and a greater risk for unfavorable
and along the bony edges (Fig. 86-12). The latter can be associated with outcome (odds ratio 2.21; 95% CI 1.14-4.26; p = 0.02) while rates
new hematoma formation. There is also lack of consensus as to the exact of death at 6 months were similar in both groups (surgical 19% and
timing of craniectomy. Intuitively, decompression should be performed medical 18%). In this study refractory ICP was defined as ICP around
as soon as neuromedical ICP management fails and prior to irreversible 20 mm Hg for a short time period whereas practicing physicians
secondary brain injury from uncontrolled ICP and brain swelling. A would use medical therapy for longer time periods. Further, close to
reasonable approach seems to indicate decompressive surgery either at 3500 patients were screened to enroll 155 patients because patients
the time of surgery for a focal mass lesion (ie, the need is evidenced by with a mass lesion (eg, hematoma) were excluded, as were patients with
the extent of intraoperative brain swelling) or to immediately proceed to successful control of increased ICP. Early surgical evacuation of focal
surgery when ICP is refractory to protocol-based maximal neuromedi- mass lesions is indicated in all severe TBI patients and in many cases
cal therapy. Neurosurgical consultation should occur early to optimize the operating surgeon intraoperatively decides to extend the surgery
a timely team approach. It is essential for the nonsurgeon to mutually to include craniectomy because of severe brain swelling. For example,
formulate with the operative colleague an a priori care approach includ- in a multicenter survey involving 726 TBI patients undergoing sur-
ing defining refractory ICP (eg, ICP >25 mm Hg for >15 minutes after gery because of an intradural mass lesion about one-third required
escalation of nonsurgical measures). also a mostly unilateral decompressive procedure at the side of the
Complications of decompressive craniectomy occur in approxi- hematoma. Therefore, the study population represents a selected,
162
mately 30% of patients. After craniectomy, subdural hygroma forma- small subgroup of severe TBI patients. This problem will be at least
165
tion (16%-50%), contralateral development of subdural or epidural in part addressed in another trial called Randomized Evaluation of
hematoma (6%-25%), hydrocephalus (2%-29%), excessive herniation Intracranial Pressure (RESCUEicp) in which patients are randomly
through the skull defect (up to 26% depending on the definition), assigned to either standard care or standard care plus craniectomy
and intracranial infections (2%-6%) have been reported. The removed (either bifrontal decompression or unilateral wide decompression)
bone is stored either within the patient’s abdominal tissue pouch or when maximal medical therapy cannot maintain ICP <25 mm Hg for
under sterile conditions at an organ bank. The bone is placed back more than 1 to 12 hours. 169
into the skull defect (cranioplasty) at a variable time point following
craniectomy once the brain parenchyma has sufficiently decompressed ■ LARGE SUPRATENTORIAL HEMISPHERIC INFARCTION
to allow for bone replacement, usually 6 to 8 weeks later. Perioperative While large, supratentorial cerebral hemispheric infarctions (LHI) are
infection (about 11%) and bone flap resorption and sinking after cra- not common (accounting for less than 10% of all ischemic strokes), they
nioplasty (up to 12%) can complicate this procedure. The syndrome are associated with a high mortality rate (70%-80%) and severe disabil-
of the trephined has been described after craniectomy and includes ity in survivors when standard medical management is used. 170,171 As a
headaches, memory disturbance, mood alteration, dizziness, and result, physicians involved with the management of these patients must
sometimes contralateral upper extremity weakness not due to the ini- be equipped with a contemporary management strategy to minimize
tial injury. It is reversed by cranioplasty. Paradoxical herniation has disability and mortality in patients in whom survival is desired and in
165
been described as a complication of lumbar puncture after extensive keeping with the patient’s life philosophy. LHI defines a group of patients
craniectomy 166 with disabling strokes at risk for variable degrees of infarct extension,
■ ALGORITHM APPROACH TO ELEVATED ICP (SEE FIG. 86-18) brain swelling, and life-threatening brain herniation due to intracranial

Figure 86-18 represents an algorithmic approach in the management hypertension. Furthermore, progress becomes quite predictable when
serial bedside examination and neuroimaging are utilized to determine
of elevated ICP. deterioration. This helps guide decision-making regarding the imple-
mentation of early interventions.
GENERAL DISEASE-SPECIFIC COMMENTS In addition to the usual priorities of general systemic care (eg, respi-
ratory, cardiovascular, and nutritional) and general stroke care (eg,
While we cannot provide an exhaustive delineation of management glucose control, fever management, DVT prophylaxis), patients who
recommendations for all causes of intracranial hypertension, we would suffer from an LHI should receive thoughtful application of medical
like to address disease-specific recommendations for some of the causes treatments and monitoring to optimize brain perfusion, minimize
most commonly encountered in a medical critical care setting. brain swelling, and limit brain tissue shifts. There should be early dis-
■ TRAUMATIC BRAIN INJURY cussion with the patient (if possible), family, and surrogates regarding
(1) the patient’s life priorities and directives prior to the stroke as they
One of the most deleterious forms of secondary injury is intracranial may apply to decision-making regarding level of care and employing
hypertension due to global cerebral edema. Surgical decompressive aggressive therapy in the context of a disabling stroke; (2) a strategic
craniectomy, nowadays most commonly in the form of bilateral fron- monitoring plan for early detection of deterioration and brain swelling
totemporoparietal bone removal, is performed in severe TBI patients should be implemented; (3) and other professionals (eg, neurosurgeons,
with medically refractory ICP elevations with increasing frequency. palliative care specialists) should be engaged for the timely application
However, until very recently there was only one small, prospective, ran- of treatments necessary in case of significant worsening. Factors that
domized trial that used bitemporal decompression without durotomy increase the likelihood of mortality include high National Institutes
in 27 children (no longer an accepted surgical approach) and supported of Health Stroke Scale scores, early drowsiness, and early nausea and
surgical therapy. A landmark multicenter randomized controlled vomiting. 172-176 These prognostic factors are generally associated with
167
Decompressive Craniectomy (DECRA) investigated standard neuro- larger infarctions; CT and MRI studies predictably confirm a correla-
critical care versus standard care plus early decompression employing tion between supratentorial infarction volume and outcome. 177,178 All

section06.indd 816 1/23/2015 12:56:11 PM