- Email: [email protected]
Alternate phototherapy in neonatal hyperbilirubinemia
178
Abstracts
This has been attributed to diminished hepatic glycogen stores, since after glucose treatment an increased hyperglycemic response has been observed (Cornblath, M., and Schwartz, R.: Disorders of carbohydrate metabolism in infancy, Philadelphia London, 1966, W. B. Saunders Company, p. 96). The present authors' findings were quite different. They reported a decrease in blood glucose in both normal and hypoglycemie infants following large doses of glucagon, despite preloading with glucose. Evidently, there is still much to be learned about neonatal carbohydrate metabolism in general and the pathophysiology of hypoglycemia in particular. The authors postulated an abnormality in the adenyl cylase system and this, together with other parts of the complicated chain of events which ultimately lead to degradation of glycogen, may require further investigation in the newborn infant.
7. Criteria for exchange transfusion in the newborn infant M. C. Hart and W. Woznicki, ~ Kansas City, Mo. Criteria for exchange transfusion for prevention of kernicterus remain unsatisfactory. Sephadex absorbs unconjugated bilirubin (BR) that is not firmly bound to albumin in human serum ("free" BR). Presence of this form of BR has been associated with the occurrence of kernicterus. We have developed ultramieromethods for total BR, serum albumin, and Sephadex column filtration of BR allowing repeated sampling with minimal blood loss even in small preterm infants. Total BR is measured spectrophotometricaliy in phosphate buffer. Albumin is determined by a modified bromocresol-green method. The presence of "free" BR is assessed with a G25 fine Sephadex column primed with phosphate enabling analysis of eluates for BR. The in vitro BR binding capacity of individual and pooled infant sera was analyzed by adding aliquots of BR. Second, Sera from hyperbilirubinemic infants were analyzed for in vivo presence of free BR. The amoimt of BR bound in vitro by newborn serum albumin varies directly with the total BR (bound BR ~-~ 0.839 total BR + 1.762, r ~ 0.969). Further the bilirubin/ albumin (B/A) ratio varies directly with the level of total BR (B/A ratio ~-~ 0.0256 total BR + 0.092t, r = 0.905). Data from 20 hyperbilirubinemic infants with total serum bilirubins from 12.5 to 29.9 mg. per cent corroborated the in vitro data. Two infants showed "free" BR ,at molar B/A ratios of 0.81 and 0.6 while the others, ranging from 0.5 to 0.91 molar did not. One infant exhibited symptoms of lcernicterus, the other did not. These data indicate that while the B/A ratio is usefuI as a guide to the risk for development of kernicterus, there is need for direct assessment of free BR." Thus Sephadex filtration may play an important role in determining the need for exchange transfusion.
The Journal o[ Pediatrics July 1972
COMMENT. Sephadex column filtration provides a simple, clinically available method of measuring free bilirubin. Of 5 infants with free bilirubin, symptoms of kernlcterus were recognized in one infant and could not be excluded in two infants. Acidosis, phototherapy, hemolysis, and blood group incompatibility did not influence the likelihood of developing kernlcterus. The effects of free fatty acids or heine pigments were not studied. The level of free billrubin at which kernicterus occurs remains to be defined.
8. Alternate phototherapy in neonatal hyperbilirubinemia R. D. Zachman, Madison, Wis. There is little doubt about the effectiveness of phototherapy in lowering the serum bilirubin levels in low-birth-weight neonates, and its use is widespread. However, several hazards of phototherapy for the human neonate have been suggested recently. The severity of these hazards could possibly be reduced by exposing neonates to phototherapy for shorter periods of time. The objective of this study was to investigate the relative effectiveness of continuous phototherapy when compared to alternate phototherapy. Twentyeight low-birth-weight newborn infants were randomly selected for one of two phot0therapy groups. Infants in the continuous phototherapy group were exposed to Vita-Lite fluorescent light delivering 450 to 500 direct incidence foot-candles for 72 hours. Others were treated with the same light source for 12 hour periods, alternating with 19 hour periods of no phototherapy for a total of 72 hours. The groups were similar in weight distribution, gestational age, admission criteria, and other treatment. The infants were begun on phototfierapy when their bilirubin level was 8 to 10 rag. per cent on either Day 2 or Day 3 of life. After initiation of phototherapy, continuous or alternate, there was no significant rise in the serum bilirubin (at 95 per cent confidence level). Bilirubln levels on Day 6 were significantly (95 per cent confidence level) lower than on Day 3 in both groups. At the same time, there was no difference in the serum bilirubin levels between the continuous and alternate groups themselves on Day 3 or Day 6. This study suggests that with low-birth-weight infants whose serum bilirubln has reached 8 to 10 my. per cent on Day 2 or 3, phototherapy for only 12 hours per day was as effective as continuous phototherapy for a 3 day period. CO~ME~T. Similar results have previously been reported in both Caucasian and Negro infants using alternate periods of 6 hours of phototherapy with 2 hours of no phototherapy (J. PEDIATR. 75: 1045, 1969). The basis for assuming increased safety of alternate phototherapy was questioned. It was suggested that alternate phototherapy might be less hazardous since there is "less of the toxin."
Abstracts
This has been attributed to diminished hepatic glycogen stores, since after glucose treatment an increased hyperglycemic response has been observed (Cornblath, M., and Schwartz, R.: Disorders of carbohydrate metabolism in infancy, Philadelphia London, 1966, W. B. Saunders Company, p. 96). The present authors' findings were quite different. They reported a decrease in blood glucose in both normal and hypoglycemie infants following large doses of glucagon, despite preloading with glucose. Evidently, there is still much to be learned about neonatal carbohydrate metabolism in general and the pathophysiology of hypoglycemia in particular. The authors postulated an abnormality in the adenyl cylase system and this, together with other parts of the complicated chain of events which ultimately lead to degradation of glycogen, may require further investigation in the newborn infant.
7. Criteria for exchange transfusion in the newborn infant M. C. Hart and W. Woznicki, ~ Kansas City, Mo. Criteria for exchange transfusion for prevention of kernicterus remain unsatisfactory. Sephadex absorbs unconjugated bilirubin (BR) that is not firmly bound to albumin in human serum ("free" BR). Presence of this form of BR has been associated with the occurrence of kernicterus. We have developed ultramieromethods for total BR, serum albumin, and Sephadex column filtration of BR allowing repeated sampling with minimal blood loss even in small preterm infants. Total BR is measured spectrophotometricaliy in phosphate buffer. Albumin is determined by a modified bromocresol-green method. The presence of "free" BR is assessed with a G25 fine Sephadex column primed with phosphate enabling analysis of eluates for BR. The in vitro BR binding capacity of individual and pooled infant sera was analyzed by adding aliquots of BR. Second, Sera from hyperbilirubinemic infants were analyzed for in vivo presence of free BR. The amoimt of BR bound in vitro by newborn serum albumin varies directly with the total BR (bound BR ~-~ 0.839 total BR + 1.762, r ~ 0.969). Further the bilirubin/ albumin (B/A) ratio varies directly with the level of total BR (B/A ratio ~-~ 0.0256 total BR + 0.092t, r = 0.905). Data from 20 hyperbilirubinemic infants with total serum bilirubins from 12.5 to 29.9 mg. per cent corroborated the in vitro data. Two infants showed "free" BR ,at molar B/A ratios of 0.81 and 0.6 while the others, ranging from 0.5 to 0.91 molar did not. One infant exhibited symptoms of lcernicterus, the other did not. These data indicate that while the B/A ratio is usefuI as a guide to the risk for development of kernicterus, there is need for direct assessment of free BR." Thus Sephadex filtration may play an important role in determining the need for exchange transfusion.
The Journal o[ Pediatrics July 1972
COMMENT. Sephadex column filtration provides a simple, clinically available method of measuring free bilirubin. Of 5 infants with free bilirubin, symptoms of kernlcterus were recognized in one infant and could not be excluded in two infants. Acidosis, phototherapy, hemolysis, and blood group incompatibility did not influence the likelihood of developing kernlcterus. The effects of free fatty acids or heine pigments were not studied. The level of free billrubin at which kernicterus occurs remains to be defined.
8. Alternate phototherapy in neonatal hyperbilirubinemia R. D. Zachman, Madison, Wis. There is little doubt about the effectiveness of phototherapy in lowering the serum bilirubin levels in low-birth-weight neonates, and its use is widespread. However, several hazards of phototherapy for the human neonate have been suggested recently. The severity of these hazards could possibly be reduced by exposing neonates to phototherapy for shorter periods of time. The objective of this study was to investigate the relative effectiveness of continuous phototherapy when compared to alternate phototherapy. Twentyeight low-birth-weight newborn infants were randomly selected for one of two phot0therapy groups. Infants in the continuous phototherapy group were exposed to Vita-Lite fluorescent light delivering 450 to 500 direct incidence foot-candles for 72 hours. Others were treated with the same light source for 12 hour periods, alternating with 19 hour periods of no phototherapy for a total of 72 hours. The groups were similar in weight distribution, gestational age, admission criteria, and other treatment. The infants were begun on phototfierapy when their bilirubin level was 8 to 10 rag. per cent on either Day 2 or Day 3 of life. After initiation of phototherapy, continuous or alternate, there was no significant rise in the serum bilirubin (at 95 per cent confidence level). Bilirubln levels on Day 6 were significantly (95 per cent confidence level) lower than on Day 3 in both groups. At the same time, there was no difference in the serum bilirubin levels between the continuous and alternate groups themselves on Day 3 or Day 6. This study suggests that with low-birth-weight infants whose serum bilirubln has reached 8 to 10 my. per cent on Day 2 or 3, phototherapy for only 12 hours per day was as effective as continuous phototherapy for a 3 day period. CO~ME~T. Similar results have previously been reported in both Caucasian and Negro infants using alternate periods of 6 hours of phototherapy with 2 hours of no phototherapy (J. PEDIATR. 75: 1045, 1969). The basis for assuming increased safety of alternate phototherapy was questioned. It was suggested that alternate phototherapy might be less hazardous since there is "less of the toxin."