I read with great interest the article by Brashear et al,1 demonstrating the effect of handling on preterm infants. They showed that preterm infants had significant changes in heart rate and oxygen saturation when exposed to stressful care procedures (SPCs), defined as "direct or indirect procedures causing physical uneasiness or annoyance or disrupting the balance between the neonate and its environment." Although transcutaneous bilirubin (TcB) was not listed as an SPC in Brashear et al's Table 1,1 we assume it is an SPC, just like the temperature measurement.
TcB is used as a screening tool for monitoring neonatal jaundice. We recently published the value of TcB as a screening tool for monitoring jaundice in term infants in the first 6 hours of life.2 Sankar et al3 extended the role of TcB as a screening tool for monitoring jaundice in extremely preterm (EP) infants. They showed a good correlation between TcB and serum bilirubin levels. The advantage of TcB is that it is a noninvasive tool; however, it is an SPC. Using the readily available indwelling umbilical catheters, we monitor total serum bilirubin (TSB) in EP infants. To minimize blood volume, some centers use point-of-care devices to measure TSB.4-6 The other caveat in measuring TcB in these EP infants is the interference with phototherapy. Most EP infants required early phototherapy, which could mask the TcB readings.7
The findings of Brashear et al1 and Sankar et al3 pose an important question: Do we need TcB in EP infants in addition to TSB? To find the answer, we performed a quick scan of our neonatal intensive care unit to see the range of TSB levels and the time taken to obtain the first TSB in a selected group of EP infants born at less than 30 weeks' gestational age. We screened 9 EP infants. The time range for the first TSB varied from 6 to 26 hours (Table 1). The TSB ranged from 2.2 to 6.6 mg/dL. Our unit policy is to obtain the laboratory test as morning laboratory test results (drawn from 5 to 6 AM). The infant (case 2) was born at 23:29 and had bilirubin drawn the next morning (6 hours). The infants (cases 6 and 7, twins) were born at 4:25 and 4:26 AM and had the laboratory test results drawn the next morning (24 and 25 hours). All our infants had their blood drawn through the umbilical arterial or venous catheters (which one is available). We do not obtain electrolytes (the complete metabolic profile [CMP]) at admission. CMP is ordered as the morning laboratory test result.
In summary, concerning the findings of Brashear et al,1 TcB should be regarded as an SPC. It is helpful in term infants,2 but its use in preterm infants should be viewed critically. In high-risk cases, TSB could be obtained with admission laboratory test results. The risk of changes in heart rate and oxygen saturation with serial TcBs could be detrimental to EP infants.
-Shabih Manzar, MD, MPH
Department of Pediatrics
Louisiana State University Health Sciences Center
Shreveport
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