Perioperative monitoring of intracranial pressure using optic nerve sheath diameter in paediatric liver transplantation

Optic Nerve Ultrasound Evaluation in Children: A Review

Managing patients with neurocritical illness requires monitoring and treating elevated intracranial pressure (ICP), especially in cases in children. In terms of precise and real-time measurements, invasive ICP measurements are presently the gold standard for the initial diagnosis and follow-up ICP assessments. As a rapid and non-invasive way to detect elevated ICP, point-of-care ultrasonography (POCUS) of optic nerve sheath diameter (ONSD) has been proposed. The utility of bedside POCUS of ONSD to detect elevated ICP with excellent diagnostic test accuracy in adults has already been demonstrated. Nonetheless, data on the relationship between POCUS of ONSD and ICP in children are scarce. Therefore, the purpose of this review is to point out the most recent findings from the pediatric published literature and briefly discuss what was assessed with ONSD ultrasound examination, and also to describe and discuss the diagnostic procedures available for optic nerve ultrasound appraisal. A search of the medical databases PubMed and Scopus was carried out. The terms such as "ocular ultrasonography", "ICP assessment", "children", "point-of-care ultrasound", and "POCUS" were searched. In conclusion, the use of the standardized A-scan technique coupled with the B-scan technique should be suggested to provide data that are as accurate, precise, repeatable, and objective as possible.

Optic nerve sheath diameter in children with acute liver failure: A prospective observational pilot study

BACKGROUND & AIMS

Early detection of raised intracranial pressure (ICP) improves outcome in acute liver failure (ALF). We evaluated the feasibility of bedside, ultrasound-guided measurement of optic nerve sheath diameter (ONSD) in normal and ALF children and correlation of ONSD with grade of hepatic encephalopathy (HE), international normalized ratio (INR) and blood ammonia (BA).

METHODS

Forty-one ALF and 47 healthy children (5-18 years) were prospectively enrolled and 12 hourly clinical evaluation was done. Laboratory parameters including INR and BA were recorded. ONSD was measured at admission, change in HE grade and at recovery in ALF, and once in controls.

RESULTS

One hundred and twenty-one ONSD measurements (ALF-74, controls-47) were taken without complications. ONSD was 4.2 (3.9-4.3), 4.4 (4.0-4.6), 5.2 (4.8-5.8) and 3.9 (3.3-4.1) mm in controls, ALF without HE, with HE and at recovery respectively. ONSD was significantly higher in ALF with HE than those without HE. ALF without HE and at recovery had ONSD similar to controls. ONSD was higher in ALF with the clinical signs of raised ICP than those without (5.4 [4.9-5.7] vs 4.6 [4.1-5.3] mm; P = .01). ONSD of 4.6 mm differentiated ALF with HE vs without HE and 5.1 mm between poor vs good non-transplant outcome with ≥80% sensitivity and specificity. ONSD positively correlated with INR (r = .53, P < .001) and BA (r = .42, P = .002).

CONCLUSIONS

ONSD can be safely and easily measured in ALF children and correlates with HE grade, INR and BA. Normal ONSD in children (>4 years) is <4.5 mm and value of >5.1 mm in ALF requires urgent attention.