December 1975
TheJournalofPEDIATRICS
977
The lack of effect of phototherapy on serum bilirubin-binding capacity in newborn infants Using a Sephadex G-25 separation technique, the total bilitv~bin-binding capacity was measured in 18 jaundieed infants before and after phototherapy. The initial total bilirubin-binding capacity obtained at 20 to 113 hours of age averaged 17.5 + 4.4 mg/dl (mean +_ SD) and was unchanged during phototherapy at 34 to 135 hours of age. In ten infants, the total bilirubin-binding capacity was measured before, during, and 24 hours after the cessation of phototherapy. Here too, phototherapy did not significantly influence the TBBC. These data indicate that in vivo, phototherapy does not alter the serum bilirubin binding capacity of newborn infants.
William J. Cashore, M.D., Edward H. Karotkin, M.D., Leo Stem, M.D., and William Oh, M.D.,* Providence, R. I.
P H O T O T H E R A P Y is an effective means of lowering serum bilirubin levels in jaundiced newborn infants, the possible hazards of exposure to high intensity light are still uncertain? Light-induced changes in the albumin molecule, or competitive binding of a phototherapy breakdown product to albumin, could decrease the binding affinity of serum albumin for bilirubin and render such therapy self-defeating. Odell and associates -~ have reported a decreased bilirubin-binding capacity of albumin in vitro following dye-sensitized photo-oxidation of human serum albumin. 2 The present study is an investigation of the effect of phototherapy in vivo on bilirubin binding capacity, using a Sephadex G-25 technique that measures the specific binding of bilirubin to albumin. ALTHOUGH
MATERIALS
AND METHODS
Eighteen infants undergoing phototherapy were the subjects of this study. Their gestational ages ranged from 26 to 40 weeks, and birth weights from 935 to 3,685 gin. Clinical diagnoses included idiopathic neonatal jaundice
From the Department of Perinatal Medicine, Women & Infants Hospital of Rhode Island, Brown University Program in Medicine. *Reprint address: Women & In]ants Hospital of Rhode Island, 50 Maude St., Providence, R. L 02908.
in ten infants; jaundice was probably associated with breast feeding in two infants, A-O or B-O blood group incompatibility in four infants, and neonatal sepsis in two infants. At the time light therapy was begun, serum indirect-acting bilirubin levels ranged from 6.4 to 18.0 mg/dl. When jaundice became clinically apparent, and before any treatment was undertaken, measurements of reserve bilirubin-binding capacity and total bilirubin-binding capacity were performed, as described below. The patients were 20 to 113 hours of age at the time of these initial measurements. Reserve and total bilirubin-binding capacity were measured a second time at 14 to 39 hours after the start of phototherapy (mean = 22 hours). The mean duration of phototherapy was 54 hours (19 to 106 hours); in ten of the 18 patients, the measurements of bilirubin-binding capacity were repeated 13 to 41 hours after discontinuation of phototherapy (mean = 26 hours). Phototherapy was given by four 30-Watt fluorescent lamps mounted in a shelf 50 cm above the bed surface of a standard incubator (Air-Shields lsolette, Narco Medical Co., Warminster, Pa.). Total and direct serum bilirubin concentrations were measured by the Martinek micromodification of the Malloy and Evelyn technique? Reserve and total bilirubinbinding capacity were determined by Sephadex G-25 gel
Vol. 87, No. 6, part 1, pp. 977-980
978
Cashore et al.
The Journal of Pediatrics December 1975
Table I. Serum indirect bilirubin, reserve b i l i r u b i n - b i n d i n g capacity, and total bilirubin-binding capacity before, during, and after p h o t o t h e r a p y
Serum albumin eonc~on~Indirect Patient Weight (gm)
bilirubin* (mg/ dl)
Pre- ~ Duying ~ Post I Pre-
During ~fiost
Reserve bilirubin binding capacity* (mg/dl) Pre- I During
Total bilirubinbinding capacity* (mg/ dl)
Pos--W
Post
I
M.O.R. R.I.C. M.I.Z. H.I. L.A.P. M.A.R. G.O. D.U.M. M.A.N. P.E.S. J.O.N. B.U.N. C.A.R. J.A. R.E. J.O.H. C.A.R. S.A. Mean • SD p (paired "t")
3,400 3,085 2,610 980 1,050 2,240 2,015 935 1,960 1,740 2,890 1,725 1,930 2,410 3,515 2,430 3,685 2,390 2,275 810 -
--3.90 2.85 3.70 2.90 2.35 2.85 3.75 2.65 -2.60 2.90 2.90 4.30 4.75 3.35 3.30 0.70 -
3.75 --2.80 3.05 3.40 3.10 2.75 -3.75 2.50 2.75 2.95 3.20 --4.70 3.20 3.20 0.60 " ns
------3.25 3.40 -3.20 2.60 2.70 2.80 -4.75 3.10 3.20 0.65 ns
18.0 13.9 11.0 6.6 7.7 14.0 10.8 6.7 6.4 10.0 10.0 15.8 6.4 13.0 8.5 8.7 13.6 18.0 11.1 3.8
16.5 10.1 10.7 9.0 8.3 10.2 11.8 7.2 5.4 11.4 15.6 9.4 9.4 12.2 10.5 8.6 13.8 16.6 10.9 3.0
-
ns
----
TheJournalofPEDIATRICS
977
The lack of effect of phototherapy on serum bilirubin-binding capacity in newborn infants Using a Sephadex G-25 separation technique, the total bilitv~bin-binding capacity was measured in 18 jaundieed infants before and after phototherapy. The initial total bilirubin-binding capacity obtained at 20 to 113 hours of age averaged 17.5 + 4.4 mg/dl (mean +_ SD) and was unchanged during phototherapy at 34 to 135 hours of age. In ten infants, the total bilirubin-binding capacity was measured before, during, and 24 hours after the cessation of phototherapy. Here too, phototherapy did not significantly influence the TBBC. These data indicate that in vivo, phototherapy does not alter the serum bilirubin binding capacity of newborn infants.
William J. Cashore, M.D., Edward H. Karotkin, M.D., Leo Stem, M.D., and William Oh, M.D.,* Providence, R. I.
P H O T O T H E R A P Y is an effective means of lowering serum bilirubin levels in jaundiced newborn infants, the possible hazards of exposure to high intensity light are still uncertain? Light-induced changes in the albumin molecule, or competitive binding of a phototherapy breakdown product to albumin, could decrease the binding affinity of serum albumin for bilirubin and render such therapy self-defeating. Odell and associates -~ have reported a decreased bilirubin-binding capacity of albumin in vitro following dye-sensitized photo-oxidation of human serum albumin. 2 The present study is an investigation of the effect of phototherapy in vivo on bilirubin binding capacity, using a Sephadex G-25 technique that measures the specific binding of bilirubin to albumin. ALTHOUGH
MATERIALS
AND METHODS
Eighteen infants undergoing phototherapy were the subjects of this study. Their gestational ages ranged from 26 to 40 weeks, and birth weights from 935 to 3,685 gin. Clinical diagnoses included idiopathic neonatal jaundice
From the Department of Perinatal Medicine, Women & Infants Hospital of Rhode Island, Brown University Program in Medicine. *Reprint address: Women & In]ants Hospital of Rhode Island, 50 Maude St., Providence, R. L 02908.
in ten infants; jaundice was probably associated with breast feeding in two infants, A-O or B-O blood group incompatibility in four infants, and neonatal sepsis in two infants. At the time light therapy was begun, serum indirect-acting bilirubin levels ranged from 6.4 to 18.0 mg/dl. When jaundice became clinically apparent, and before any treatment was undertaken, measurements of reserve bilirubin-binding capacity and total bilirubin-binding capacity were performed, as described below. The patients were 20 to 113 hours of age at the time of these initial measurements. Reserve and total bilirubin-binding capacity were measured a second time at 14 to 39 hours after the start of phototherapy (mean = 22 hours). The mean duration of phototherapy was 54 hours (19 to 106 hours); in ten of the 18 patients, the measurements of bilirubin-binding capacity were repeated 13 to 41 hours after discontinuation of phototherapy (mean = 26 hours). Phototherapy was given by four 30-Watt fluorescent lamps mounted in a shelf 50 cm above the bed surface of a standard incubator (Air-Shields lsolette, Narco Medical Co., Warminster, Pa.). Total and direct serum bilirubin concentrations were measured by the Martinek micromodification of the Malloy and Evelyn technique? Reserve and total bilirubinbinding capacity were determined by Sephadex G-25 gel
Vol. 87, No. 6, part 1, pp. 977-980
978
Cashore et al.
The Journal of Pediatrics December 1975
Table I. Serum indirect bilirubin, reserve b i l i r u b i n - b i n d i n g capacity, and total bilirubin-binding capacity before, during, and after p h o t o t h e r a p y
Serum albumin eonc~on~Indirect Patient Weight (gm)
bilirubin* (mg/ dl)
Pre- ~ Duying ~ Post I Pre-
During ~fiost
Reserve bilirubin binding capacity* (mg/dl) Pre- I During
Total bilirubinbinding capacity* (mg/ dl)
Pos--W
Post
I
M.O.R. R.I.C. M.I.Z. H.I. L.A.P. M.A.R. G.O. D.U.M. M.A.N. P.E.S. J.O.N. B.U.N. C.A.R. J.A. R.E. J.O.H. C.A.R. S.A. Mean • SD p (paired "t")
3,400 3,085 2,610 980 1,050 2,240 2,015 935 1,960 1,740 2,890 1,725 1,930 2,410 3,515 2,430 3,685 2,390 2,275 810 -
--3.90 2.85 3.70 2.90 2.35 2.85 3.75 2.65 -2.60 2.90 2.90 4.30 4.75 3.35 3.30 0.70 -
3.75 --2.80 3.05 3.40 3.10 2.75 -3.75 2.50 2.75 2.95 3.20 --4.70 3.20 3.20 0.60 " ns
------3.25 3.40 -3.20 2.60 2.70 2.80 -4.75 3.10 3.20 0.65 ns
18.0 13.9 11.0 6.6 7.7 14.0 10.8 6.7 6.4 10.0 10.0 15.8 6.4 13.0 8.5 8.7 13.6 18.0 11.1 3.8
16.5 10.1 10.7 9.0 8.3 10.2 11.8 7.2 5.4 11.4 15.6 9.4 9.4 12.2 10.5 8.6 13.8 16.6 10.9 3.0
-
ns
----
