Background

Use of point of care ultrasound has expanded over the last decades particularly in intensive care to the point that it is now readily available for use by the clinical care practitioners in this setting1. Today clinicians are using ultrasound at the bedside to assist in the evaluation of physiological abnormalities in a number of body systems. Ultrasound has been used to image body organs for over 50 years2. It is currently the most widely used imaging modality in medicine. Advantages are that ultrasound is portable, free of radiation risk and relatively inexpensive compared to other diagnostic modalities like magnetic resonance and computed tomography3. The main limitation when considering this for use by NICU clinicians is that it requires advanced training. In addition, when compared to traditional x-ray, ultrasound has limited penetration to air and bones and therefore structure deeper to them cannot be well assessed4

Indications

There are three general indications for ultrasound in the neonatal setting: 


1) Anatomic assessment of static organs such as the brain, lungs, liver, kidney, spleen to evaluate for anomalies, hemorrhage, space occupying lesions and abnormal fluid collections. 

2) Dynamic assessment of moving organs, such as the heart, lungs, intestine, and vascular system to evaluate blood flow and physiologic processes.

3) Locating vessels for cannulation and determining the position of catheter tips 


Anatomic ultrasound assessment of static organs should be provided by a trained radiologist. Dynamic ultrasound assessment can be performed by a trained neonatal clinician who understands the clinical details of his patients and is familiar with the underlying pathophysiologic mechanisms
5. Table 1 shows different applications performed by a trained clinician.  

Point of care Lung Ultrasound

In the last 10years, research studies have shown that lung ultrasound (LUS) is an accurate, non-invasive method for predicting ventilatory failure and offers advantages over traditional chestradiography6. LUS can accurately and reliably diagnose transient tachypnea of the newborn (TTN)and has a great value in differentiating TTN from respiratory distress syndrome (RDS)7.Additionally,  many of the other common pulmonary and pleural diseases in neonates display specific findings on LUS which can be useful in the differential diagnosis8

We developed a screening model of bedside lung ultrasound assessment for infants requiring respiratory support5. Like any other diagnostic technique it should be only used in integration with the clinical assessment,  interpreted according to the clinical presentation of the individual patient while considering particular limitations of this modality. 

Point of care Intestinal Ultrasound

Necrotising enterocolitis is a serious disorder in infants and commonly associated with complications like short bowel syndrome and total parenteral nutrition related issues. The reported mortality of up to 40%, so early diagnosis and management are essential9. The radiographic diagnosis by XR after clinical suspicion is still the standard in most Centers. The main issue with radiograph is being limited to 3 main findings, pneumatosis intestinalis (PI), portal vein gases (PVG), and perforation, and radiograph diagnosis of PI and PVG is sometimes a challenge with low sensitivity and wide range of inter-observer variability.  There has been increasing evidence that with real-time ultrasound, PI and PVG can be better detected than with x-ray10. Ultrasound is able to assess the bowel wall directly and detect bowel wall thickening or thinning, reduced peristalsis or abnormal bowel wall perfusion by color Doppler. Peritoneal fluid, both intraluminal and extra luminal is also visible11,12. This can be performed in any suspected case with compromised intestinal performance like intestinal obstruction or ischemia and not only in cases with suspected NEC.

Table 1: Different applications performed by either professional sonographer (radiologist or cardiologist) or a trained clinician 

Point of care ultrasound in Newborns

Indications 

Cranial ultrasound 

 

emergency assessment of suspected hemorrhage

Doppler assessment of cerebral arteries in cases hemodynamic instability e.g. PDA 

Intestinal ultrasound 

Urgent evaluation of suspected necrotizing entercolitis, intestinal ischemia  

Lung ultrasound 

New emerging modality for assessment of common neonatal lung diseases, e.g. RDS, TTN, meconium, pneumothorax, pleural effusions. 

Focused heart ultrasound            

 Assessment of specific neonatal hemodynamics issues 

Vascular assessment 

Blood flow by Doppler for assessment of resistance or shunting of blood through arteriovenous malformation or PDA

Interventional POCUS 

Central line placement, lumber puncture, bladder tapping for urine sample. Peritoneal and pericardial tap of significant effusions  

References

1.        Evans N, Gournay V, Cabanas F, et al. Point-of-care ultrasound in the neonatal intensive care unit: international perspectives. Semin Fetal Neonatal Med. 2011;16(1):61-68. doi:10.1016/j.siny.2010.06.005.

2.        Pereda M a., Chavez M a., Hooper-Miele CC, et al. Lung ultrasound for the diagnosis of Pneumonia in Children: A Meta-analysis. Pediatrics. 2015;135(4):714-722. doi:10.1542/peds.2014-2833.

3.        Escourrou G, De Luca D. Lung ultrasound decreased radiation exposure in preterm infants in a neonatal intensive care unit. Acta Paediatr. 2016:n/a-n/a. doi:10.1111/apa.13369.

4.        Volpicelli G, Elbarbary M, Blaivas M, et al. International evidence-based recommendations for point-of-care lung ultrasound. Intensive Care Med. 2012;38(4):577-591. doi:10.1007/s00134-012-2513-4.

5.        Elsayed Y, Abdelmawla M, Narvey M. A model of integrated lung and focused heart ultrasound as a new screening examination in infants at risk of respiratory or hemodynamic compromise. 2017;6(1):1-14. doi:10.7363/060131.

6.        Xirouchaki N, Magkanas E, Vaporidi K, et al. Lung ultrasound in critically ill patients: comparison with bedside chest radiography. Intensive Care Med. 2011;37(9):1488-1493. doi:10.1007/s00134-011-2317-y.

7.        Liu J, Cao H-Y, Wang X-L, Xiao L-J. The significance and the necessity of routinely performing lung ultrasound in the neonatal intensive care units. J Matern Neonatal Med. 2016;7058(March):1-6. doi:10.3109/14767058.2016.1152577.

8.        Copetti R, Cattarossi L. Lung Ultrasound in Newborns, Infants, and Children. 2011:241-245. doi:10.1007/978-3-642-21247-5.

9.        Dilli D, Suna Oğuz S, Erol R, Ozkan-Ulu H, Dumanlı H, Dilmen U. Does abdominal sonography provide additional information over abdominal plain radiography for diagnosis of necrotizing enterocolitis in neonates? Pediatr Surg Int. 2011;27(3):321-327. doi:10.1007/s00383-010-2737-8.

10.      Bohnhorst B. Usefulness of abdominal ultrasound in diagnosing necrotising enterocolitis. Arch Dis Child Fetal Neonatal Ed. 2013;98:F445-50. doi:10.1136/archdischild-2012-302848.

11.      Gale HI, Gee MS, Westra SJ, Nimkin K. Abdominal ultrasonography of the pediatric gastrointestinal tract. World J Radiol. 2016;8(7):656. doi:10.4329/wjr.v8.i7.656.

12.      Kim H-Y, Kim I-O, Kim WS, Kang GH. Bowel sonography in sepsis with pathological correlation: an experimental study. Pediatr Radiol. 2011;41(2):237-243. doi:10.1007/s00247-010-1806-4.