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ORIGINAL ARTICLE
Year : 2020  |  Volume : 23  |  Issue : 1  |  Page : 17-21

Reliability of transcutaneous bilirubin estimation during phototherapy in term infants: A hospital-based observational study


1 Department of Paediatrics, Vikas Hospital Pvt. Ltd, New Delhi, India
2 Department of Gastroenterology, Vikas Hospital Pvt. Ltd, New Delhi, India
3 Department of Paediatrics, Government Medical College, Srinagar, Jammu and Kashmir, India
4 Department of Accident and Emergency, Vikas Hospital Pvt. Ltd, New Delhi, India
5 School of Studies in Chemistry, Jiwaji University, Gwalior, Madhya Pradesh, India

Date of Submission06-Mar-2019
Date of Decision05-Apr-2019
Date of Acceptance16-Jun-2019
Date of Web Publication18-Mar-2020

Correspondence Address:
Dr. Jehangir Allam Bhat
Department of Paediatrics, Kurji Holy Family Hospital, Patna, Bihar
India
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DOI: 10.4103/smj.smj_11_19

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  Abstract 


Background:Blood sampling method is the most common but invasive method for bilirubin estimation. Transcutaneous bilirubin (TCB) estimation, on the other hand is non-invasive. Objectives: The aim was to compare neonatal bilirubin estimation by serum bilirubin and transcutaneous bilirubinometer methods both pre- and during phototherapy and establish the precision of transcutaneous bilirubinometer. Materials and Methods: This prospective hospital-based observational study was conducted on 350 term neonates over a period of 2 years. Bilirubin was estimated in all newborn by both serum bilirubin and transcutaneous method, at the time of admission in nursery (prephototherapy), at 6 h after phototherapy (while neonates were still under phototherapy treatment), and at withholding phototherapy, and a photo opaque patch of 2.5 cm was used to cover the area on midforehead and transcutaneous bilirubin was estimated from this area after removing it during phototherapy. All data were tabulated and analyzed by relevant statistical tests. Results: A total of 350 term healthy newborns with mean gestational age of 38 ± 2 weeks and mean birth weight of 2.97 ± 0.9 kg were studied. Correlation analysis revealed a significant correlation between total serum bilirubin and transcutaneous method (TCB) measurements of bilirubin. When these methods were compared at pre-phototherapy, at 6 hours after phototherapy and before withholding phototherapy, correlation coefficient(r) of 0.9571, 0.7988, and 0.9206 were seen respectively. The precision levels of transcutaneous bilirubinometer (BiliCheck™) were good because plotting of Bland–Altman graphs showed maximum (>97%) data within agreement limits at all stages of phototherapy. Conclusion: Our study revealed good correlation and precision of transcutaneous bilirubinometer both before and during phototherapy. Thus, it supports the previous studies which justify the use of transcutaneous bilirubinometer in assessing newborn jaundice during phototherapy.

Keywords: Bilirubin estimation, phototherapy, transcutaneous bilirubinometer


How to cite this article:
Bhat JA, Sheikh SA, Wani ZA, Ara R, Bhat SU. Reliability of transcutaneous bilirubin estimation during phototherapy in term infants: A hospital-based observational study. Sahel Med J 2020;23:17-21

How to cite this URL:
Bhat JA, Sheikh SA, Wani ZA, Ara R, Bhat SU. Reliability of transcutaneous bilirubin estimation during phototherapy in term infants: A hospital-based observational study. Sahel Med J [serial online] 2020 [cited 2020 May 26];23:17-21. Available from: http://www.smjonline.org/text.asp?2020/23/1/17/280936




  Introduction Top


Neonatal hyperbilirubinemia presents most commonly during the first week after birth.[1] Most of the newborns develop jaundice within physiological range, thus did not possess any risk. However, neonatal hyperbilirubinemia in 10% of term neonates and 25% of near term develops significant jaundice which needs treatment such as phototherapy or another modality.[2] Jaundice in newborn progresses from the head downward to feet, i.e., cephalocaudal direction.[3] The diagnosis and estimation of newborn hyperbilirubinemia is done by noninvasive methods such as visual estimation, transcutaneous estimation, and invasive methods such as serum bilirubin by blood sampling. Visual estimation is based on mechanism of cephalocaudal progression and is assessed by applying Kramer's scale.[3] This method has been shown to be less reliable in recent studies.[4] Blood sampling method is the most common and reliable method used for bilirubin estimation. However, this is often done by heel prick or venous sampling and is considered painful and cumbersome.[5] Transcutaneous bilirubin (TCB) estimation is a noninvasive method of bilirubin estimation done by TCB devices such as, Air-shields-Minolta, Bilitest, and BiliCheck™. This method has been shown to correlate well with prephototherapy serum bilirubin levels of pre- and term neonates.[6],[7]

To assess the effect of phototherapy, infants need frequent monitoring of serum bilirubin level. This is done by venous sample estimation of bilirubin, which is quite cumbersome as explained above, and visual assessment by Kramer's scale lost its significance for jaundice assessment while an infant is under phototherapy.[8] Due to these drawbacks of blood sampling and visual assessment of jaundice, transcutaneous estimation of jaundice by TCB devices is nowadays evaluated to reveal its significance in the assessment of jaundice of infants while under phototherapy. There is increasing tend nowadays to continue phototherapy of infants at home[9] where it is too difficult to visually assess or collect blood sample. Thus, TCB estimation by devices could have significant role if validated.

The aim of our study was to compare neonatal bilirubin estimation by serum bilirubin and transcutaneous bilirubinometer methods both pre- and during phototherapy and establish the precision of transcutaneous bilirubinometer during phototherapy treatment.


  Materials and Methods Top


Study setting and design

This study is prospective, observational and hospital-based in design and involved 350 term neonates recruited over a period of 2 years (January 2017 to December 2018). The study was carried out on in Vikas Hospital, Najafgarh, New Delhi.

This was a prospective hospital-based observational study conducted on 350 term neonates over a period of 2 years from January 2017 to December 2018 in Vikas Hospital, Najafgarh, New Delhi, under the RCT code of ACRVXET-0008763 on 1st January 2017 which was provided by Hospital Scientific and Ethics Committee after approving this research proper consent was obtained from parents or guardians of the study newborns. All the procedures have been carried out as per the guidelines given in the Declaration of Helsinki 2013.

Inclusion criteria

Healthy term newborns who required phototherapy as per the American Academy of Pediatrics Guidelines[10] were included in the study.

Exclusion criteria

Newborns who had Conjugated hyperbilirubinemia, septicemia, life-threating congenital anomalies and congenital infections were excluded from the study.

Ethical consideration

Ethical approve for the study was obtained (RCT code of ACRVXET-0008763 dated 1st January 2017) as approved by Hospital Scientific and Ethics Committee. Consent was obtained from parents or guardians of the study newborns. All the procedures have been carried out as per the guidelines given in the Declaration of Helsinki 2013.

All newborns at the time of prephototherapy were subjected to bilirubin estimation both by serum bilirubin and TCB method. Transcutaneous bilirubinometer used in our study was multiwavelength spectral reflectance meters (BiliCheck™). BiliCheck™which give the reading in mg/dl. However, other meters such as twin wavelength spectral reflectance meters give reading in the form of transcutaneous bilirubin index which then has to be converted to value in mg/dl using available formulae/chart. Serum bilirubin was estimated by microbilirubin (Jendrassik–Grof method), for that venous blood is taken in four microcapillaries and centrifuged at the rate of 10,000 rpm for 5 min, then bilirubin estimation is done spectrophotometrically using beam method (55 nm wavelength) (micro la300, Merck, the Netherlands). Calibration of bilimeter is done daily using labetalol solution. Under phototherapy besides protective coverage of eyes and genitals, a portion of the middle forehead was covered by 2.5-cm photo-opaque patch (BilEclipse Phototherapy Patch, Respironics, Murrysville, PA, USA).

Newborns were then shifted to phototherapy unit and the next measurement of bilirubin by both methods was done at 6 h after phototherapy and at withholding of phototherapy. All measurements for bilirubin by transcutaneous bilirubinometer were taken from the (patched) area before, during, and at the time of withholding phototherapy after removing the patch.

Statistical analysis

All data were collected, tabulated, and assessed by SPSS (Statistical Package for the Social Sciences) version 22, Chicago, IL, USA. The agreement between total serum bilirubin (TSB) and TCB was done by Pearson's correlation. To strengthen this correlation, we used Bland–Altman analysis to assess TSB and TCB variability.


  Results Top


A total of 350 term healthy newborns of the mean gestational age of 38 ± 2 weeks and mean birth weight of 2.97 ± 0.9 kg were studied. The means of total serum bilirubin (TSB) by sampling method and transcutaneous method (TCB) and their differences at pre phototherapy, at 6 hrs of phototherapy and before withholding phototherapy are shown in [Table 1]. The statistical difference in mean values of bilirubin by both methods (TSB and TCB measurement methods) at prephototherapy time was 0.0103 ± 0.568 with P = 0.987 at 6 h after phototherapy was −0.9897 ± 0.546 and P = 0.897 and at withholding of phototherapy was −0.9897 ± 0.62 and P = 0.765. As all the three P values were >0.05, thus no significant statistical differences between TCB and TSB readings were recorded at any stage of phototherapy [Table 1].
Table 1: Total serum and transcutaneous bilirubin levels before and during phototherapy (mg/dl)

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Linear regression and Pearson's correlation analysis revealed a significant correlation between TSB and TCB measurement with correlation coefficient (r) of 0.9571, 0.7988, and 0.9206 when prephototherapy, at 6 h of phototherapy, and before withholding phototherapy levels were compared, respectively. All comparison showed P < 0.0001 which further strengthened the correlation [Table 2] and [Figure 1]a, [Figure 2]a, and [Figure 3]a. The level of precision of transcutaneous bilirubinometer (BiliCheck™) was demonstrated by plotting Bland–Altman graphs by comparing difference versus average of measurements between TCB and TSB at various stages of phototherapy (prephototherapy [Figure 1]b, at 6 h after phototherapy [Figure 2]b, and at withholding of phototherapy [Figure 3]b). All figures reveal >98% of readings fall within the limits of agreement (95% confidence intervals).
Table 2: Correlation of total serum bilirubin with transcutaneous bilirubin at various stages of intensive phototherapy

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Figure 1: Scattered plot (a) and Bland–Altman plot (b) of total serum bilirubin and transcutaneous bilirubin before starting phototherapy

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Figure 2: Scattered plot (a) and Bland–Altman plot (b) of total serum bilirubin and transcutaneous bilirubin after 6 h of phototherapy

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Figure 3: Scattered plot (a) and Bland–Altman plot(b) of total serum bilirubin and transcutaneous bilirubin at withholding phototherapy

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  Discussion Top


This study showed comparable correlation with good agreement between bilirubin estimation by serum sampling and transcutaneous method estimation during prephototherapy and phototherapy. There were no statistical differences between estimation of bilirubin by transcutaneous and TSB methods at any stage of phototherapy (pre- or during phototherapy) if the transcutaneous estimation is done from the area which is covered by photo-opaque patch. The correlations of TCB and TSB before, at 6 h, and at withholding phototherapy were also significant and comparable. This finding is supported by previous research of Alsaedi,[11] who in his study showed a significant correlation between TCB and TSB before starting phototherapy and during phototherapy (r: 0.85; P < 0.001, and r: 0.80; P < 0.001), respectively. Pendse et al.[12] also proved TCB has a good correlation with TSB after initiation of phototherapy (r = 0.918, P < 0.001).

Our study revealed a good level of precision of transcutaneous bilirubinometer both pre- and during phototherapy as proved by Bland–Altman graphs in which maximum values lied between confidence interval of 95% (limits of agreement). Alsaedi[11] and Pendse et al.[12] also proved good precision of transcutaneous bilirubinometer by showing 90% of the data points were in the 95% confidence interval which are the limits of agreement in Bland–Altman graphs.

Strengths and Limitations

Main limitations of our study were measuring of TCB level from single site (patched forehead), thus site comparison must have been taken into consideration. Other limitation of our study was estimation of TCB at 6 h after phototherapy, and we do not know if the same correlation will exist while measuring bilirubin levels at longer or smaller intervals.

The strength of our study was its prospective nature, good, and homogenous (term babies only) sample size.


  Conclusion Top


Our study revealed good correlation and precision of transcutaneous bilirubinometer both before and during phototherapy. Thus, it supports the previous studies which justify the use of transcutaneous bilirubinometer in assessing newborn jaundice during phototherapy. This study will have implication in developing countries where nonavailability of trained staff and micromethods of serum bilirubin estimation is quite high. The main advantage of this study is alleviation of parental anxiety because of frequent venous pricking in bilirubin estimation by invasive methods.

Acknowledgment

We are highly thankful to our senior colleagues and paramedical staff who constantly guided and helped us while conducting this research.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Maisels MJ. Jaundice. In: MacDonald MG, Seshia MMK, Mullett MD, editors. Neonatology: Pathophysiology and Management of the Newborn. 6th ed. Philadelphia: Lippincott Williams & Wilkins; 2005. p. 768-846.  Back to cited text no. 1
    
2.
Sarici SU, Serdar MA, Korkmaz A, Erdem G, Oran O, Tekinalp G, et al. Incidence, course, and prediction of hyperbilirubinemia in near-term and term newborns. Pediatrics 2004;113:775-80.  Back to cited text no. 2
    
3.
Kramer LI. Advancement of dermal icterus in the jaundiced newborn. Am J Dis Child 1969;118:454-8.  Back to cited text no. 3
    
4.
Moyer VA, Ahn C, Sneed S. Accuracy of clinical judgment in neonatal jaundice. Arch Pediatr Adolesc Med 2000;154:391-4.  Back to cited text no. 4
    
5.
Szabo P, Wolf M, Bucher HU, Fauchère JC, Haensse D, Arlettaz R. Detection of hyperbilirubinaemia in jaundiced full-term neonates by eye or by bilirubinometer? Eur J Pediatr 2004;163:722-7.  Back to cited text no. 5
    
6.
Teran CG, Mohamed T, Casey J. Transcutaneous bilirubinometry: Comparison of two multiwavelength devices in healthy term newborns. Eur J Pediatr 2011;170:1485.  Back to cited text no. 6
    
7.
Fouzas S, Karatza AA, Skylogianni E, Mantagou L, Varvarigou A. Transcutaneous bilirubin levels in late preterm neonates. J Pediatr 2010;157:762-60.  Back to cited text no. 7
    
8.
Cloherty JP, Eichenwald EC, Hansen AR, Martin CR, Stark AR(eds). Cloherty and Stark's Manual of newborn care: Neonatal Hyperbilirubinemia. 7th ed. Wolter Kluwer: Philadelphia; 2008. p. 336-7.  Back to cited text no. 8
    
9.
Reyes CA, Stednitz DR, Hahn C, Mutchie KD, McCullough SR, Kronberg K. Evaluation of the BiliChek being used on hyperbilirubinemic newborns undergoing home phototherapy. Arch Pathol Lab Med 2008;132:684-9.  Back to cited text no. 9
    
10.
American Academy of Pediatrics Subcommittee on Hyperbilirubinemia. Management of hyperbilirubinemia in the newborn infant 35 or more weeks of gestation. Pediatrics 2004;114:297-316.  Back to cited text no. 10
    
11.
Alsaedi SA. Transcutaneous bilirubin measurements can be used to measure bilirubin levels during phototherapy. Hindawi Int J Pediatr 2018:1-5.  Back to cited text no. 11
    
12.
Pendse A, Jasani B, Nanavati R, Kabra N. Comparison of transcutaneous bilirubin measurement with total serum bilirubin levels in preterm neonates receiving phototherapy. Indian Pediatr 2017;54:641-3.  Back to cited text no. 12
    


    Figures

  [Figure 1], [Figure 2], [Figure 3]
 
 
    Tables

  [Table 1], [Table 2]



 

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