DIFFUSE AXONAL INJURY (DAI) IS NOT ASSOCIATED WITH ELEVATED INTRACRANIAL-PRESSURE (ICP)

Objective. Traditionally, intracranial pressure (ICP) monitoring has b een utilized in all patients with severe head injury (Glasgow coma sco re of 3-8). Ventriculostomy placement, however, does carry a 4 to 10 p ercent complication rate consisting mostly of hematoma and infection. The authors propose that a subgroup of patients presenting with severe head trauma and diffuse axonal injury without associated mass lesion, do not need ICP monitoring. Additionally, the monitoring data from IC P, MAP, and CPP for a comparison severe head injury group, and subgrou ps of DAI would be presented. Materials and methods. Thirty-six patien ts sustaining blunt head trauma and fitting our strict clinical and ra diographic diagnosis of DAI were enrolled in our study. Inclusion crit eria were severe head injury patients who did not regain consciousness after the initial impact, and whose CT scan demonstrated characterist ic punctate hemorrhages of < 10 mm diameter at the greywhite junction, basal ganglia, corpus callosum, upper brainstem, or a combination of the above. Patients with significant mass lesions and documented anoxi a were excluded. Their intracranial pressure (ICP) and cerebral perfus ion pressure (CPP) were compared to a control group of 36 consecutive patients with severe non-penetrating non-operative head injury, using the Analysis for Variance method. Results. Eighteen (50.0%), six (16.7 %), and twelve (33.3%) patients had types I, II, and III DAI, respecti vely. The admission Glasgow Coma Score (GCS) was higher for types I an d II than for type III DAI. ICP was monitored from 23 to 165 hours, wi th a mean ICP for 36 patients of 11.70 mmHg (SEM = 0.75) and a range f rom 4.3 to 17.3 mmHg. Of all ICP recordings, of which 89.7% (2421/2698 ) were less than or equal to 20 mmHg. Average mean arterial pressure ( MAP) was 96.08 mmHg (SEM = 1.69), and 94.6% (2038/2154) of all MAP rea dings were greater than 80 mmHg. Average cerebral perfusion pressure ( CPP) was 85.16 mmHg (SEM = 1.68), and 90.1% (1941/2154) of all CPP rea dings were greater than 70 mmHg. This is compared to the control group mean ICP, MAP, and CPP of 16.84 mmHg (p = 0.000021), 92.80 mmHg (p = 0.18), and 76.49 mmHg (p = 0.0012). No treatment for sustained elevate d ICP > 20 mmHg was needed for DAI patients except in two; one with ex tensive intraventricular and subarachnoid hemorrhage who developed com municating hydrocephalus, and another with ventriculitis requiring int rathecal and intravenous antibiotic treatments. Two complications, one from a catheter tract hematoma, and another with Staph epidermidis ve ntriculitis, were encountered. All patients, except type III DAI, gene rally demonstrated marked clinical improvement with time. The outcome, as measured by Glasgow Coma Score (GCS) and Glasgow Outcome Score (GO S) was similarly better with types I and II than type III DAI. Conclus ion. The authors conclude that ICP elevation in DAI patients without a ssociated mass lesions is not as prevalent as other severe head injure d patients, therefore ICP monitoring may not be as critical. The prese nce of an ICP monitoring device may contribute to increased morbidity. Of key importance, however, is an accurate clinical history and inter pretation of the CT scan.