Determination of normal values of optic nerve sheath diameter in newborns with bedside ultrasonography

Optic Nerve Sheath Diameter Ultrasound: A Non-Invasive Approach to Evaluate Increased Intracranial Pressure in Critically Ill Pediatric Patients

Early diagnosis of increased intracranial pressure (ICP) is crucial for prompt diagnosis and treatment of intracranial hypertension in critically ill pediatric patients, preventing secondary brain damage and mortality. Although the placement of an external ventricular drain coupled to an external fluid-filled transducer remains the gold standard for continuous ICP monitoring, other non-invasive approaches are constantly being improved and can provide reliable estimates. The use of point-of-care ultrasound (POCUS) for the assessment of ICP has recently become widespread in pediatric emergency and critical care settings, representing a valuable extension of the physical examination. The aim of this manuscript is to review and discuss the basic principles of ultra-sound measurement of the optic nerve sheath diameter (ONSD) and summarize current evidence on its diagnostic value in pediatric patients with ICP. There is increasing evidence that POCUS measurement of the ONSD correlates with ICP, thus appearing as a useful extension of the physical examination in pediatrics, especially in emergency medicine and critical care settings for the initial non-invasive assessment of patients with suspected raised ICP. Its role could be of value even to assess the response to therapy and in the follow-up of patients with diagnosed intracranial hypertension if invasive ICP monitoring is not available. Further studies on more homogeneous and extensive study populations should be performed to establish ONSD reference ranges in the different pediatric ages and to define cut-off values in predicting elevated ICP compared to invasive ICP measurement.

Evaluation of the correlation of the new Ballard scoring with the ultrasonographic optical nerve sheath diameter and brain volume of preterm infants

BACKGROUND

Optic nerve sheath diameter (ONSD) measurements with magnetic resonance imaging and ultrasonography in preterm infants are similar.

AIM

We measured ultrasonographic ONSD and calculated the brain volumes of preterm infants using two-dimensional cranial ultrasonography and explored the relationships thereof with gestational age, birth weight, head circumference, and new Ballard score.

METHOD

This prospective study included preterm infants admitted to the neonatal intensive care unit without intracranial pathology. Two images per eye were obtained from a linear array ultrasound transducer placed on the patient's superior eyelid. The ONSD was measured 3 mm behind the globe. The brain was considered an ellipsoid, and estimated absolute brain volumes were calculated by subtracting the volumes of the two lateral ventricles from the total brain volumes.

RESULTS

A total of 143 preterm infants (male 74, female 69) included in the study. The mean gestational age of the study population was 29.7 weeks (23-36), and the mean birth weight was 1390 g (500-2850). There was a significant difference in ONSD between the male and female gender. A significant, strong, and positive correlation was found between ONSD measurements and gestational age (r 0.901, p < 0.001), new Ballard score (r 0.946, p < 0.001), birth weight, head circumference, and brain volumes.

CONCLUSION

Our results suggested that ONSD measurements are highly correlated with anthropometry, and it could be a promising bedside, non-invasive objective tool for the determination of exact gestational age postnatally along with the new Ballard score.

Measurement of optic nerve sheath diameter by ultrasound in healthy term neonates

BACKGROUND

Optic nerve sheath diameter (ONSD) ultrasound is a noninvasive and repeatable tool to dynamically evaluate intracranial pressure with high diagnostic accuracy; however, data in neonates are scarce. The aim of this study was to determine the reference value of ONSD and potential influencing factors in healthy term neonates.

METHODS

We retrospectively reviewed 250 full-term neonates who underwent cranial ultrasound as part of selective newborn screening over a 2-year period. Neonates with any of the following conditions were excluded: using mechanical ventilation, sedatives and/or vasopressors, or signs of infection which needed cerebrospinal fluid analysis and/or intracranial pathologies. Data on sex, gestational age, birth body weight, birth body height, birth head circumference, Apgar score and types of delivery were collected. The neurodevelopmental outcomes were reviewed.

RESULTS

A total of 234 neonates (123 girls and 111 boys) were included. The mean ONSD value was 3.30 ± 0.27 mm in the right eye and 3.30 ± 0.23 mm in the left eye, with no significant difference between both eyes (p = 0.797). Male neonates had a larger ONSD than female neonates (3.34 ± 0.22 mm versus 3.26 ± 0.20 mm, p = 0.007), and ONSD was correlated with birth weight in the males. Otherwise, there were no statistically significant associations between ONSD and other birth characteristics in both sexes. Most (63%) cases were followed for at least 12 months, and 98% had normal neurodevelopment.

CONCLUSION

The reference value reported in this study may be used to evaluate the ONSD in healthy term neonates. Sex differences should be considered in this age group.

Determination of ventriculoperitoneal shunt dysfunction using optic nerve sheath diameter measurement on CT scan in pediatric patients with hydrocephalus

PURPOSE

We aimed to evaluate whether optic nerve sheath diameter (ONSD) measurement by computed tomography (CT) can be a diagnostic criteria for the detection of ventriculoperitoneal shunt dysfunction among children whose fontanels are still open.

METHODS

Patients with a ventriculoperitoneal shunt who were currently showing clinical and radiological signs of acute hydrocephalus depending on the shunt dysfunction were included in this study. The study was designed to compare the preoperative and postoperative ONSDs of three groups of patients divided according to their ages: group 1, patients aged < 4 months; group 2, patients aged 4-18 months; and group 3, patients aged > 18 months.

RESULTS

We included 138 patients (mean age, 35.18 ± 51.01 months). Among the patients, 46.4% were females and 53.6% were males. ONSD measurements in the preoperative period were < 2.86 ± 0.59 in group 1, 3.93 ± 0.82 in group 2, and 5.40 ± 0.81 in group 3 and those in the postoperative period were 2.02 ± 0.38 in group 1, 2.72 ± 0.62 in group 2, and 3.64 ± 0.81 in group 3. Right, left, and mean ONSDs increased significantly in the three groups and were found to be statistically significant.

CONCLUSION

ONSD measurement in CT has been evaluated as an appropriate finding that can be used especially in acute hydrocephalus, when clinical and radiological findings are not diagnostic.

Is Ocular Sonography a Reliable Method for the Assessment of Elevated Intracranial Pressure in Children?

Point-of-care ultrasound has been widely used by clinicians at the bedside in recent years. Various types of point-of-care ultrasound practices are employed, especially in pediatric emergency rooms and intensive care units. Pediatric intensive care specialists perform point-of-care ultrasound virtually as a part of physical examination since it provides just-in-time vital clinical information, which could assist in acute management strategies in critically ill patients. Measurement of optic nerve sheath diameter using point-of-care ultrasound is a noninvasive and radiation-free technique to determine raised intracranial pressure. Ophthalmic artery and central retinal artery Doppler indices can be used as transcranial Doppler to assess raised intracranial pressure. The aim of this review was to provide detailed information on ultrasonographic measurements of optic nerve sheath diameter and central retinal artery Doppler indices as techniques of interest for predicting increased intracranial pressure in pediatric patients in view of the literature.

A new stethoscope for pediatric intensivists: Point-of-care ultrasound

In recent years, the use of point-of-care ultrasound by non-radiologist physicians has become widespread. Especially for clinicians working in pediatric emergency departments and pediatric intensive care units, point-of-care ultrasound has almost become a part of physical examinations due to the rapid responses it offers to the problems of critically ill patients. Numerous studies revealed the important clinical benefits of point-of-care ultrasound use by pediatric intensive care providers. In this review, we aimed to give detailed information about different types of point-of-care ultrasound applications in pediatric intensive care units and wanted to draw attention to the increased use and clinical benefits of this noninvasive and radiation free technique.