|Year : 2018 | Volume
| Issue : 2 | Page : 232-237
Relevance of the jaundice meter in determining significant bilirubin levels in term neonates at a tertiary hospital in Lagos State
Oyejoke Oyapero1, Fidelis O Njokanma2, Elizabeth A Disu2
1 Department of Paediatrics, Lagos State University Teaching Hospital, Ikeja, Lagos, Nigeria
2 Department of Paediatrics, Lagos State University College of Medicine, Ikeja, Lagos, Nigeria
|Date of Web Publication||27-Dec-2018|
Dr. Oyejoke Oyapero
Department of Paediatrics, Lagos State University Teaching Hospital, Ikeja, Lagos
Source of Support: None, Conflict of Interest: None
Background and Aim: Jaundice is the yellowish discoloration of the skin and mucous membranes or the visible manifestation as a result of elevated serum bilirubin. With spectroscopic tools now available, it is possible to assess the skin's condition by quantitative measures and to access information from deeper layers of skin not visible to the eye. The aim of this study was to determine the relevance of the jaundice meter in determining significant bilirubin levels in term neonates at a tertiary hospital in Lagos State using the Konica Minolta JM-103. Materials and Methods: One hundred and fifty consecutive neonates who presented at the neonatal unit of the hospital were recruited for the study after checking them with set inclusion and exclusion criteria. The transcutaneous bilirubinometry (TcB) readings of the neonates were taken on the forehead, sternum, and abdomen of the calm neonate in a supine position, and blood samples for total serum bilirubin (TSB) estimation were drawn from a peripheral vein within 10 min of TcB measurement. Pearson's correlation analysis with linear regression was done to test the relationship between TSB and TcB values as well as for TcB measurements taken at different sites. Results: The difference between the bilirubin values measured with TcB and TSB was low, with 104 neonates (69.3%) having a difference that was <0.9 mg/dl. Over 83% of the neonates had TcB values that were higher than TSB values, and the percentage of neonates with TSB values >12 mg/dl was 45.2% compared with 56.8% obtained by TcB. In the present study, bilirubin levels measured with the JM-103 show a good agreement with TSB levels in the study neonates. A comparison of the extent of neonatal jaundice in our study at the different body sites using the Kramer's chart showed that there were similar mean recordings for TcB and TSB, with mean values of 10.27 ± 2.90 and 10.58 ± 2.90 for involvement of the face/neck and 18.34 ± 1.61 and 18.43 ± 1.42 for hand/feet obtained by TSB and TcB, respectively. Conclusion: The excellent correlation of TcB with TSB obtained from this study even at levels of bilirubin that necessitates the initiation of phototherapy is encouraging. The JM-103 device thus appears relevant in determining significant bilirubinemia in black neonates.
Keywords: JM-103, significant neonatal jaundice, total serum bilirubin, transcutaneous bilirubinometry
|How to cite this article:|
Oyapero O, Njokanma FO, Disu EA. Relevance of the jaundice meter in determining significant bilirubin levels in term neonates at a tertiary hospital in Lagos State. Arch Med Health Sci 2018;6:232-7
|How to cite this URL:|
Oyapero O, Njokanma FO, Disu EA. Relevance of the jaundice meter in determining significant bilirubin levels in term neonates at a tertiary hospital in Lagos State. Arch Med Health Sci [serial online] 2018 [cited 2019 Jul 15];6:232-7. Available from: http://www.amhsjournal.org/text.asp?2018/6/2/232/248655
| Introduction|| |
Jaundice is the yellowish discoloration of the skin and mucous membranes or the visible manifestation as a result of elevated serum bilirubin. In neonates, evaluation of the sclera is difficult due to physiological photophobia. Jaundice becomes apparent on the skin when serum bilirubin exceeds 5 mg/dl. In most neonates, hyperbilirubinemia reflects a normal transitional phenomenon. However, in some neonates, serum unconjugated bilirubin levels may rise excessively and if untreated can progress to bilirubin encephalopathy resulting to a lifelong neurologic sequelae. In Sub-Saharan Africa, especially in Nigeria, significant neonatal jaundice is a leading cause of death in newborn nurseries and long-term neurological impairment in survivors., After several years of neglect and exclusion from the global child health agenda under the Millennium Development Goals (MDGs), initiative, neonatal jaundice is increasingly being acknowledged as an important contributor to global neonatal deaths. The emerging interest in the early childhood developmental difficulties faced by many survivors of neonatal diseases under the MDG framework has also drawn attention to neonatal jaundice.
Bilirubin encephalopathy is a clinically significant condition with about 1.1 million neonates at risk globally every year, and about three-quarters of mortality occurs in Sub-Saharan Africa and South Asia. Significant neonatal jaundice, which can result in bilirubin encephalopathy, accounts for about 19.4%–45.6% of admissions into special care baby units in Nigeria.,, These figures are largely underestimated however since the vast majority of babies born in Nigeria are not delivered in hospitals. The cost of care of patients with bilirubin encephalopathy throughout their lives runs to millions of naira. The use of a screening device that has the potential to promptly identify significant neonatal jaundice and possibly reduce the prevalence of bilirubin encephalopathy is thus desirable in Nigeria.
Research has shown that practitioners provide wide ranges of estimates of bilirubin concentrations based on their clinical observations on inspection and may be limited by skin pigmentation, plethora, decreased ambient light, and exposure to sun or phototherapy. The yellow discoloration of the skin first appears on the face and then progresses to the trunk, the palm of the hand, and the sole of the feet in a cephalocaudal pattern. Another technique for estimating serum bilirubin that is real-time, noninvasive, painless, and relatively inexpensive is the use of transcutaneous bilirubinometry (TcB). This method offers an objective assessment compared to visual evaluation by a clinician. With spectroscopic tools now available, it is possible to assess the skin's condition by quantitative measures and to access information from deeper layers of skin not visible to the eye.
Comparisons between total serum bilirubin (TSB) and TcB, however, have some limitations. In preterm infants, TcB may be less accurate as results are affected by the immature skin and by a different albumin-to-bilirubin binding ratio. Bilirubin levels vary considerably between neonatal populations depending on certain environmental and epidemiologic factors. Hyperemia at the test site may also affect the results as well as measurements taken against bruises, birthmarks, and subcutaneous hematoma. In a multiethnic study, a uniform correlation was found between TcB and TSB measurements in infants with varying degrees of skin pigmentation. However, in another study that had a significant number of African-American infants, correlation of TcB with TSB was better in Caucasian infants than in their African-American counterparts. A similar result was obtained by Maisels et al. in yet another multiethnic study.
The rate of rise of the level of bilirubin is very important, and a collaborative multicenter perinatal project of 27,000 infants in the United States of America observed that their neurological development during the 1st year of life has a relationship with their maximal serum bilirubin concentration after birth. The exact bilirubin concentration associated with bilirubin encephalopathy in the healthy term babies is unknown. A threshold of 12 mg/dl has, however, been agreed upon by many professional bodies and international guidelines as the value at which TcB values should be confirmed with a TSB due to the risk of bilirubin encephalopathy., Early identification of infants at risk of severe hyperbilirubinemia is an essential component of newborn care. However, because of the high prevalence of the physiological jaundice, pathological jaundice may be underestimated or inappropriately treated at home and in health facilities. This has contributed to the prevalence of acute bilirubin encephalopathy, cerebral palsy, mental abnormalities, irreparable liver pathology, and cirrhosis in developing nations., The aim of this study was to determine the relevance of the jaundice meter in determining significant bilirubin levels in term neonates at a tertiary hospital in Lagos State.
| Materials and Methods|| |
This was a prospective descriptive study that aimed to determine the relevance of the jaundice meter in determining significant bilirubin levels in term neonates at Lagos State University Teaching Hospital (LASUTH).
Study setting and location
The study was carried out at the neonatal wards of LASUTH which is a tertiary health facility situated in the capital of Lagos State and financed by the Lagos State Government. It is a multispecialty hospital with a bed complement of 741, with about 110 pediatric beds of which nearly half are for neonates.
Successive patients who were brought to the LASUTH neonatal unit were recruited for the study after screening them and checking them with set inclusion and exclusion criteria.
Sample size determination
This was determined using the formulae: N = Z pq/d2
N = Number of patients (estimated sample size)
p = Prevalence of neonatal jaundice in a previous study
q = 1 − p
Z = Standard normal deviate
d = Precision of the study (5%)
Z = 1.96 which is the standard normal deviate at 95% confidence
p = 26.5% = 0.256
q = 0.744 d = 0.05
N = (1.96 × 0.256 × 0.744)/(0.05 × 0.05)
= 150 patients.
- Term neonates with gestational age of 37 completed weeks and above (determined on the basis of the date of the last menstrual period or first-trimester ultrasound findings) and with a birth weight not <2500 g
- Neonates who presented with jaundice
- Those who had been deemed to have jaundice by the attending physician were included in the study.
- Neonates who may require urgent emergency treatment
- Neonates with any skin bruising, local nevus, hemangioma, or melanotic patch on the forehead, sternum or abdomen which could affect the accuracy of TcB readings
- Those whose parents were unwilling to give their informed consent and did not want to participate in the study
- Neonates whose bilirubin values were unrecordable with the JM-103™ due to their high level of jaundice were also excluded from the study. (TcB values are unrecordable above 19.6 mg/dl). Such neonates would have no TcB scores to compare with TSB values
- Neonates who had been exposed to sunlight and those who were given phenobarbitone. Phenobarbitone produces significant reduction in plasma bilirubin levels and can potentially affect the correlation between TcB and TSB.
Ethical approval was obtained from the LASUTH Health Research and Ethics Committee, GRA, Ikeja, Lagos. Written parental informed consent was also obtained before enrolling children in the study. The form gave a simple language description of the study, the names and affiliation of investigators, the right to withdraw at any time, the ethics committee approval, and the privacy guarantee.
Data collection was executed using a structured interviewer-administered questionnaire to obtain the parents' medical, social, and behavioral information, the neonate's gestational age at birth, postnatal age at the time of TcB, and the mother's ethnicity. The neonates' detailed medical history and physical examination findings were also documented and a provisional clinical diagnosis was made.
All the TcB readings were done by the principal investigator (OO) using Minolta Konica Jaundice Meter, JM-103™ (Daisennishimachi, Sakaiku, Osaka, Japan). The recordings were done on the forehead, sternum, and abdomen of the tranquil neonate in a supine position. The forehead recording was taken 2 cm above the glabella with the eyes shielded appropriately while taking the readings. The abdominal recordings were taken 3 cm above the umbilicus while the sternal recording was done at the mid-point of the sternum. The probe was sanitized with 70% isopropyl alcohol after using it on each baby. The recordings over each measurement site were displayed as the TcB level in mg/dl. An average value of three readings from each site in mg/dl was documented.
Total serum bilirubin estimation
The blood samples for TSB were taken by the principal investigator (OO) in the Neonatology unit. Blood samples were drawn from a peripheral vein within 10 min of TcB measurement and transferred into heparinized specimen bottles. The bottles were placed in a light-proof box and transported to the laboratory straightway for total bilirubin determination. TSB levels were determined in the hospital's clinical chemistry laboratory using Beckman Coulter SYNCHRON CX5® automated chemistry analyzer utilizing the diazo method. The Beckman Coulter SYNCHRON CX5® automated chemistry analyzer was calibrated daily according to the manufacturers' requirement using a commercially available control serum supplied with the machine by the medical laboratory scientist to ensure accuracy and consistency of the results obtained. The values gotten from the TSB result was recorded for each patient.
Blood collection equipment
These included a light-proof box for transferring the blood samples, lithium heparin bottles, disposable gloves, adhesive tape/plaster, sterile gauze pads (2” × 2”), tourniquets and sterile syringes/needles.
Chemicals and reagents
Three reagents that were used for the TSB analysis were: Reagent 1 contained HCl (117.6 mmol/l), sulfanilic acid (4.62 mmol/l) and cetrimide (27.44 mmol/l). Reagent 2 contained sulfanilic acid (14.61 mmol/l) in HCl (116.7 mmol/l) while Reagent 3 contained sodium nitrite (145 mmol/l).
- TcB meter model name: Minolta Konica Jaundice Meter, JM-103™ (Daisennishimachi, Sakaiku, Osaka, Japan). The dimensions of the meter are 4.8 cm (1.9”) wide × 15.4 cm (6.0”) high × 3.2 cm (1.2”) deep. It measures in the range of 0.0 to 20 mg/dl or 0 to 340 μmol/l. The light source is a pulsed xenon arc lamp with silicon photodiodes
- TSB machine model name: Beckman Coulter SYNCHRON CX5 automated chemistry analyzer.
Data were managed for analysis using the Statistical Package for the Social Sciences version 20.0 software for Windows (SPSS Inc., Chicago, IL, United States). Chi-square test was utilized to decide the level of association among the categorical variables, while the paired Student's t-test and ANOVA test were used to compare the means of TcB readings and TSB levels. Pearson's correlation analysis with linear regression was done to test the relationship between TSB and TcB values as well as for TcB measurements taken at different sites. The mean bias and imprecision of TcB compared with TSB measurement was calculated using the method of Bland and Altman. The mean bias was defined as the mean difference between each paired TcB and TSB measurement. Imprecision was taken at ±2 standard deviation from the mean difference. Limits of agreement of the mean differences were given as 95% confidence intervals and a 5% level of significance was adopted.
| Results|| |
One hundred and fifty neonates were included in the study; 89 (59.33%) were male and 61 (40.67%) were female. Most of the neonates (129; 86%) were of 37–39-week gestational age while others were 40–42 weeks. About one-third (56; 37.33%) presented in the clinic between 24 and 48 h of life with neonatal jaundice [Table 1].
[Table 2] describes the extent of neonatal jaundice in the study neonates. The mean TSB for neonates with neonatal jaundice extending to the face was 10.27 ± 2.90 mg/dl while the value for neonates with jaundice extending to the sole of the feet was 18.34 ± 1.61 mg/dl. The corresponding mean TcB values for the neonates were 10.58 ± 2.90 and 18.43 ± 1.42 mg/dl, respectively.
[Table 3] shows the paired t-test between TSB and TcB bilirubin measurements on the forehead, sternum, and abdomen as well as the mean of the total TcB values. The percentage difference in the bilirubin values obtained at the forehead, sternum, and abdomen was 6.4%, 8.1%, and 9.7%, respectively.
|Table 3: Paired t-test of total serum bilirubin with transcutaneous bilirubin at the three body sites|
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[Figure 1] shows the Pearson's correlation of total serum bilirubin with mean transcutaneous bilirubinometry. Using linear regression analysis, the correlation of TcB with TSB was 0.924. (p= 0.000).
|Figure 1: Pearson's correlation of total serum bilirubin with mean transcutaneous bilirubinometry|
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[Figure 2] shows the Error Bland–Altman plot between the difference of total serum bilirubin-transcutaneous bilirubinometry and the mean total serum bilirubin + mean transcutaneous bilirubinometry Mean difference between the two assays was 0.97 mg/dl (95% CI: 0.74–1.21). The imprecision was ±2.96 mg/dl.
|Figure 2: Error Bland–Altman plot between the difference of total serum bilirubin-transcutaneous bilirubinometry and the mean total serum bilirubin + mean transcutaneous bilirubinometry|
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| Discussion|| |
The main purpose of this research was to determine the relevance of the jaundice meter in determining significant bilirubin levels in term neonates at a tertiary hospital in Lagos State using the Konica Minolta JM 103. The transcutaneous bilirubinometer has been evaluated in a number of studies and has been proposed to be a valuable screening device that might aid in decreasing the length of stay or rate of readmission of neonates. These results were achieved with no trauma to the patient, no risk of infection, and potentially reduced cost of monitoring serum bilirubin by minimizing the use of hospital personnel and supplies. In addition, as Knudsen and Brodersen had suggested that the routine use of transcutaneous bilirubin measurements could lead to a reduction in the incidence of kernicterus. Even though many of these researches were conducted across the world, there are only a handful of Nigerian studies.,
The mean TSB value of the study neonates was 12.26 ± 3.65 mg/dl while the mean TcB was 13.25 ± 3.60 mg/dl. The variance between the bilirubin values determined with TcB and TSB was thus low, with most of the neonates (69.3%) having a difference that was <0.9 mg/dl. Over 83% of the neonates had TcB values that were >TSB values, and the percentage of neonates with TSB values >12 mg/dl was 45.2% compared with 56.8% obtained by TcB. This indicates that higher values of bilirubin are obtained when Minolta JM-103 is used for screening. This was in agreement with a recent Nigerian study by Kayode-Adedeji et al. who observed in their study that the real-world implication of this is a probable slight increase in the frequency of interventions with phototherapy if only the TcB readings were used for the determination of the severity of jaundice and in clinical judgment.
On clinical examination, newborn jaundice is observed to have cephalocaudal progression and Kramer systematically correlated advancing dermal zones of jaundice with actual serum bilirubin levels. Some studies have established that skilled neonatologists are capable of using the cephalocaudal progression of jaundice to precisely estimate bilirubin levels and recognize infants with significant hyperbilirubinemia, while others have found that visual assessment is neither dependable nor accurate for predicting bilirubin levels. A comparison of the extent of neonatal jaundice in our study at the different body sites using the Kramer's chart showed that there were similar mean recordings for TcB and TSB, with mean values of 10.27 ± 2.90 and 10.58 ± 2.90 for involvement of the face/neck and 18.34 ± 1.61 and 18.43 ± 1.42 for hand/feet obtained by TSB and TcB, respectively. It is noteworthy that TSB and TcB values above 12 mg/dl were obtained with neonatal jaundice with extent from the umbilicus to knees. The exact bilirubin concentration associated with bilirubin encephalopathy in the healthy term babies is unknown. The risk of acute advanced and chronic bilirubin encephalopathy among term and late preterm babies increases with higher TSB level. Acute bilirubin encephalopathy can occur with lower TSB levels in the presence of neurotoxicity risk factors such as sepsis and rhesus incompatibility. A threshold of 12 mg/dl has, however, been agreed upon by many professional bodies and international guidelines as the value at which TcB values should be confirmed with a TSB due to the risk of bilirubin encephalopathy.,
TcB has been documented to correlate well with TSB in neonates whose serum bilirubin level was below 14.62 mg/dl. There is a lack of data on the reliability of transcutaneous estimation of bilirubin at levels above 14.62 mg/dl. In a study by William et al., which aimed to correlate TcB with TSB in a predominantly Hispanic population, the correlation was found to be poor when TSB values were >10 mg/dl. The usefulness of TcB was found to be limited in neonates with relatively high TSB, but this is not clinically significant since such levels are far higher than the levels at which an intervention with phototherapy is indicated. A paired t-test of the TcB recordings obtained at the forehead, sternum, and abdomen showed that even though there was a significant difference in these values, the difference in the readings obtained at each of these sites was <1 mg/dl. This was in consonance with previous screening studies signifying a strong association between TcB and TSB measurements, with correlation coefficients ranging from 0.75 to 0.95.,, TcB recordings have established linear correlation with TSB, and some investigators have recommended its use as a screening device to detect clinically significant jaundice and thus decrease the need for frequent blood sampling in the term neonates.,,
| Conclusion|| |
TcB correlates well with serum bilirubin over the ranges that necessitate initiation of phototherapy in the black neonate, making it a reliable screening tool for detection of significant neonatal jaundice.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3]