Page 90 - JSOM Fall 2025

can detect elevated ICP at its inception, before papilledema Because of the ongoing critical resuscitation, only one mea-
develops; it can be completed rapidly, at the point of care and surement was taken per eye at each time period; a total of six
can be repeated to trend values; other modalities requiring measurements were taken (Figures 1–6). In two of the images,
equipment (like CT or MRI scanners) or expertise (e.g., neu- slight variances appear secondary to the time pressure under
rosurgery) are often not available to combat casualties; and which the measurements were made—in Figure 3, the depth
measuring ONSD is a skill that can be acquired relatively was measured at 3mm, but the caliper at the globe was inad-
quickly. 4,7,9,19 vertently moved after the measurement was completed, mak-
ing the measurement appear to have been taken at 3.8mm; in
Against this backdrop, we report the case of a patient present- Figure 5, the caliper measurement of 3mm was not perpen-
ing as a level 1 trauma patient with a penetrating traumatic dicular to the optic nerve, thereby minimally shortening the
head injury who received a bolus of 250mL 3% hypertonic retrobulbar distance. The results of the six measurements and
saline to treat presumed elevated ICP. ONSD measurements the times at which they were taken are presented in Table 1.
taken before, during, and after administration of this hyper-
tonic saline bolus showed a reduction in the ONSD of 0.6mm Following transfer, the patient was treated nonoperatively and,
in the right eye (from 5.4 to 4.8mm) and 1.3mm in the left eye at the time of writing, remains intubated and ventilated in a
(from 7.6 to 6.3mm) within 20 minutes. To our knowledge, long-term acute care facility. Efforts were made to locate the
our data are the first reported demonstration of real-time re- patient’s next of kin without success; approval for this case
duction in ONSD following emergency treatment for elevated report was provided by the institutional ethics committee.
ICP in the context of acute penetrating head trauma.
Discussion
Case Presentation
Although debate continues as to the optimal cutoff for
The patient presented to a military treatment facility as a an ONSD, multiple studies have shown that an ONSD of
level 1 trauma case with a penetrating traumatic head injury. greater than 5mm measured on ultrasound is concerning for
The individual had been endotracheally intubated in the field increased ICP, 4,10–12 and a recent meta-analysis reviewing 22
using ketamine and rocuronium. During the primary survey, studies reported 5.82mm as the mean ONSD measurement in
endotracheal tube placement was confirmed using video laryn- patients with elevated ICP. Patients with traumatic head in-
20
goscopy. The remainder of the primary survey was significant jury have repeatedly been shown to have ONSD greater than
for a hemostatic penetrating wound to the right skull; initial 5mm, 4,5,6,11,17,21 and use of ultrasound for ONSD assessment
blood pressure of 102/55mmHg, a heart rate of 127 beats has been proposed as a screening tool for head trauma patients
per minute; palpable pulses in all four extremities; 2mm non- in both civilian and military contexts. 3,5,9,11
reactive pupils; and a Glasgow Coma Scale (GCS) score of 3T.
The secondary survey was significant for a 4×2cm penetrating Ultrasound measurement of the ONSD of head trauma pa-
wound to the right parietal skull without a corresponding sec- tients for monitoring, assessment of treatment efficacy, and
ondary or exit wound. prognostication is an evolving approach. 4,17,18,22,23 Thotakura
et al. reported that the patients included in their study “with
The patient’s chest and pelvic X-rays were negative for acute descending trend[s] in ONSD values had good outcome[s]
traumatic injury, and the extended focused assessment with and required no surgery” and concluded that “[s]erial mea-
sonography for trauma (eFAST) was negative. An X-ray of the surements of ONSD in head injury patients will help in the
skull was significant for right-sided skull fractures with intra- intermittent monitoring of elevated ICP.” As mentioned
18
cranial radio-opaque fragments. previously, the JTS CPG already recommends serial ONSD
measurements during prolonged field care of unconscious TBI
The patient received the following intravenous medications: patients without ocular injury.
3
cefazolin 2g, levetiracetam 3g, 1 unit of packed red blood cells,
calcium chloride 1g, tranexamic acid 1g, and 3% hypertonic To our knowledge, the literature contains no instance of ul-
saline 250mL. After administration of a tetanus vaccine, the trasound measurement of ONSD for assessment of treatment
patient was sedated using a propofol drip and transferred as response following 3% hypertonic saline given for elevated
an emergency to a facility with neurosurgical services. ICP in TBI patients, regardless of whether the injury was blunt
or penetrating. At least one previous study found a reduction
During the patient’s resuscitation, three ultrasound measure- in ONSD after administration of 3% hypertonic saline. In a
ments of the ONSD were performed over a 17-minute period prospective, non-randomized trial in an emergency depart-
before, during, and after administration of the 3% hypertonic ment, Duyan and Vural measured ONSD in 60 patients with
saline bolus. The images were acquired by an experienced op- symptomatic hyponatremia, before and after the patients re-
erator, and the measurements were taken by a trainee under ceived either one or two boluses of 150mL 3% hypertonic sa-
the experienced operator’s supervision, using a Sonosite PX line. They found a statistically significant reduction in ONSD
cart-based ultrasound system (Fujifilm Sonosite, Bothell, WA) following treatment with hypertonic saline, although they did
with a 19-5MHz linear probe and ophthalmic settings. With not report how long after the hypertonic saline treatment the
the patient in the supine position, copious amounts of gel were second ONSD measurement was taken. 8
placed on the patient’s closed upper eyelids to facilitate imag-
ing. Care was taken not to exert pressure on the globe. The At least two studies have reported an immediate and real-time
probe was angled to bring the optic nerve into view with the reduction in ONSD with a concomitant drop in ICP. Over
lens where possible because the patient could not cooperate a period of about 6 months, Chen et al. recruited a conve-
with the examination. The ONSD was measured in the trans- nience sample of 84 patients who required outpatient lumbar
verse view at a depth of 3mm behind the globe. punctures for diagnostic purposes, and they performed ONSD

88 | JSOM Volume 25, Edition 3 / Fall 2025