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30 HOW TO TREAT : NEONATAL JAUNDICE

30 HOW TO TREAT : NEONATAL JAUNDICE

8 DECEMBER 2023 ausdoc . com . au
zones . Three babies with SBR levels in the high-risk zone were misclassified by visual assessment to be in the low-risk zones . In a prospective study of 522 infants of more than 35 weeks ’ gestation and 2.5kg or more than 36 weeks and 2kg born in Pennsylvania , the accuracy of visual assessment by nurses using a five-point scale to grade the maximum cephalocaudal extent of jaundice prior to discharge was investigated by Keren and colleagues . 52 They found there was only moderate correlation between visual assessment and bilirubin levels . The overall accuracy for predicting risk of significant neonatal hyperbilirubinaemia was low . Of note in this study , complete absence of jaundice on visual inspection had a sensitivity of 96 % and negative predictive value of 99 %.
Transcutaneous bilirubinometry
Transcutaneous bilirubinometry
( TCB ) is a non-invasive , painless ,
point-of-care method of estimating
SBR . The technique was first
described in 1978 by Peevy and colleagues
using the spectral reflectance of neonatal skin . 55 Typically , a handheld device known as a bilirubinometer
is used to direct light
into the newborn ’ s skin . The wavelength
intensity of the reflected
light is analysed by the meter to
provide an SBR level estimate by
means of a mathematical algorithm
that accounts for haemoglobin and skin pigments . 56 The device provides an immediate result , is typically
easy to use , and requires
minimal clinician training . The
location for TCB measurements has
commonly been either the sternum
or forehead . There is evidence
however , that TCB levels are often
higher on the sternum ( presumably
secondary to reduced light expo-
Figure 3 . Bilirubin metabolism .
sure ) and therefore , the sternum should routinely be used for measurement
of TCB . 56
US National Institute of Diabetes and Digestive and Kidney Diseases / bit . ly / 3IZDhRx
Bilirubinometers and TCB correlation with SBR have been extensively evaluated . In healthy newborns , correlation coefficients reportedly range from 0.70 to 0.97 . 57-68 Jones and colleagues studied the use of the newest TCB meter , the Drägar Jaundice Meter JM-105 in North Carolina to determine SBR correlation in comparison with the Philips Bili- Chek device among 176 near-term infants . 69 TCB measurements were taken on the forehead and sternum with both devices , and a SBR blood sample was obtained within 30 minutes of TCB measurement . Optimal TCB / SBR correlation was with sternal TCB samples taken with the JM-105 . Per previous studies
, significant reliability variation
was found among racial groups :
SBR was significantly overestimated
in Hispanic / Latino and African
babies and underestimated
in those of Caucasian ethnicity . 70 TCB / SBR correlation decreased
Figure 4 . Normal biliary tree .
with higher SBR levels , with a tendency to over and underpredict
equally , unlike previous studies
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Visual inspection is
estimation of hyperbilirubinae-
in healthy newborn infants of 35
days 2-5 . A total of 3532 observa-
that have raised concerns that TCB
in general , the primary , and in many developing countries , the only screening method for assessment of neonatal hyperbilirubinaemia . 10 The reliability of visual
mia has been extensively evaluated . 51-54 Riskin and colleagues prospectively studied the reliability of clinical assessment screening for neonatal hyperbilirubinaemia
weeks ’ gestation or more born during a five month period from 2003 to 2004 in a single centre in Israel . 51 Visual assessments were made by nurses and doctors on postnatal
tions were recorded in a group of 1129 newborns by 23 observers . Clinical visual estimations misclassified 61.5 % of cases of jaundice as being in the lower-risk
measurements tend to be underestimated at higher SBR levels .
62 , 71
Of the TCB / SBR paired measurements , 5 % taken on the sternum with the JM-105 underestimated