Clinical trial of tin mesoporphyrin to prevent neonatal hyperbilirubinemia

OBJECTIVE

To assess the efficacy of the heme oxygenase inhibitor, tin mesoporphyrin (SnMP), to reduce total bilirubin (TB) levels.

STUDY DESIGN

Masked, SnMP (4.5 mg kg(-1)), placebo-controlled, multicenter trial of single intramuscular injection to newborns ⩾35 weeks gestational age whose predischarge screening transcutaneous bilirubin (TcB) was >75th percentile.

RESULTS

Two hundred and thirteen newborns (median age 30 h) were randomized to treatment with SnMP (n=87) or 'sham' (n=89). We found that the duration of phototherapy was halved. Within 12 h of SnMP administration, the natural TB trajectory was reversed. At age 3 to 5 days, TB in the SnMP-treated group was +8% but sixfold lower than the 47% increase in the sham-treated group (P<0.001). At age 7 to 10 days, mean TB declined 18% (P<0.001) compared with a 7.1% increase among controls. No short-term adverse events from SnMP treatment were noted other than photoreactivity due to inadvertent exposure to white light phototherapy.

CONCLUSION

Early, predischarge SnMP administration decreased the duration of phototherapy, reversed TB trajectory and reduced the severity of subsequent hyperbilirubinemia.

Transcutaneous bilirubin levels in newborns <35 weeks' gestation

OBJECTIVE

In infants <35 weeks' gestation, we sought to define the transcutaneous bilirubin (TcB) levels at which a total serum bilirubin (TSB) level suggesting the need for phototherapy is unlikely to occur and a TSB measurement can, therefore, be avoided.

STUDY DESIGN

Nursing staff performed 896 TcB measurements within 1 h of a TSB on 225 neonates 26 0/7-34 6/7 weeks' postmenstrual age (PMA). Generalized linear models were fit with generalized estimating equations (GEEs) to model the probability of having a TSB level at or above the phototherapy initiation cutpoint as a function of the TcB; these methods allow for multiple tests per infant.

RESULTS

The mean difference between TcB and TSB measurements was <1 mg dl(-1) for each PMA category. When the TcB was at least 3 mg dl(-1) below the TSB cutpoint for phototherapy, there was a ⩾98% probability that the TSB was not at, or above, the recommended phototherapy level. The single exception to this was a phototherapy level of 6 mg dl(-1) for infants of 28 0/7-29 6/7 weeks' PMA, where a TcB of 4 mg dl(-1) below the phototherapy level (ie a TcB ⩽2 mg dl(-1)) was necessary to achieve ⩾98% probability.

CONCLUSION

Our data support the use of routine TcB screening for infants 28-34 6/7 weeks' gestation. TcB screening in the neonatal intensive care unit can identify infants who require a TSB to confirm or exclude the need for phototherapy.

Routine transcutaneous bilirubin measurements combined with clinical risk factors improve the prediction of subsequent hyperbilirubinemia

OBJECTIVE

To evaluate predischarge transcutaneous bilirubin (TcB) measurements combined with risk factors as predictors of the risk of a subsequent total serum bilirubin (TSB) >or=17 mg per 100 ml (291 micromol l(-1)).

STUDY DESIGN

Routine TcB measurements are obtained daily for all infants in our well baby nursery. We performed a nested case-control study comparing all 75 infants who had been readmitted with TSB >or=17 mg per 100 ml (291 micromol l(-1)) between 1 February 2005 and 28 February 2007 with randomly selected controls that had not been readmitted.

RESULT

Between 1 February 2005 and 28 February 2007, 11 456 infants were discharged from the well baby nursery. Seventy-five infants (0.65%) were readmitted at a mean age of 110+/-29.9 h with a TSB>or=17 mg per 100 ml (291 micromol l(-1)). All received phototherapy. Using logistic regression analysis, three variables were statistically significant for predicting cases: the maximum predischarge TcB percentile group (P<0.0001, adjusted odds ratio (AOR), >95th percentile 148; 95% confidence interval (CI) 21 to >999, AOR 76 to 95th percentile 15; 95% CI 3.1 to 70, AOR 50 to 75th percentile 6.1; 95% CI 1.3 to 28 compared with <50th percentile), exclusive breastfeeding (P<0.0001, AOR 11; 95% CI 3.7 to 34) and gestational age (P=0.0057, AOR 35 to 36 6/7 week 21; 95% CI 2.3 to 185, AOR 37 to 37 6/7 week 15; 95% CI 1.9 to 115, AOR 38 to 38 6/7 week 1.8; 95% CI 0.3 to 11, AOR 39 to 39 6/7 week 1.1; 95% CI 0.2 to 7 AOR >or=41 week 0.88; 95% CI 0.1 to 10 compared with 40 to 40 6/7 week infants). These three variables provided the best prediction of a case (c=0.885, area under the receiver operating characteristic curve) and this prediction was significantly better than the use of the clinical risk factors, gestation and exclusive breastfeeding, alone (c=0.770, P<0.001) or the TcB percentile grouping alone (c=0.766, P<0.001). Substituting the TcB rate of rise (c=0.903, P=0.316) or the last measured TcB (c=0.873, P=0.292) for the maximum TcB measurement did not significantly improve the predictors of a case.

CONCLUSION

Combining predischarge TcB levels with two clinical risk factors-gestational age and exclusive breastfeeding-significantly improves the prediction of subsequent hyperbilirubinemia.

Randomized controlled trial of light-emitting diode phototherapy

OBJECTIVE

We wished to compare the efficacy of light-emitting diode (LED) phototherapy with special blue fluorescent (BB) tube phototherapy in the treatment of neonatal hyperbilirubinemia.

STUDY DESIGN

We randomly assigned 66 infants >or=35 weeks of gestation to receive phototherapy using an LED device or BB. In addition to phototherapy from above, all infants also received phototherapy from below using four BB tubes or a fiberoptic pad.

RESULT

After 15+/-5 h of phototherapy, the rate of decline in the total serum bilirubin (TSB) was 0.35+/-0.25 mg/dl/h in the LED group vs 0.27+/-0.25 mg/dl/h in the BB group (P=0.20).

CONCLUSION

LED phototherapy is as effective as BB phototherapy in lowering serum bilirubin levels in term and near-term newborns.

Does intensive phototherapy produce hemolysis in newborns of 35 or more weeks gestation?

OBJECTIVE

Because there is some in vivo and in vitro evidence that standard phototherapy might produce hemolysis, we wished to know whether intensive phototherapy produces hemolysis.

STUDY DESIGN

We measured end-tidal carbon monoxide (CO) concentration corrected for ambient CO (ETCOc) in 27 newborn infants > or =35 weeks gestation receiving intensive phototherapy (average irradiance 43 microW/cm2/nm).

RESULTS

There was a steady decrease in the mean ETCOc over the course of the phototherapy.

CONCLUSION

Intensive phototherapy did not produce hemolysis in infants > or =35 weeks gestation.

Jaundice in low birthweight infants: pathobiology and outcome

Jaundice in preterm, as well as full term, infants results from (a) an increased bilirubin load in the hepatocyte, (b) decreased hepatic uptake of bilirubin from the plasma, and/or (c) defective bilirubin conjugation. Hyperbilirubinaemia in preterm infants is more prevalent, more severe, and its course more protracted than in term neonates.

Treatment of jaundice in low birthweight infants

Exchange transfusion and phototherapy remain the staples of intervention for the jaundiced newborn. Clinical management of the jaundiced low birthweight infant is discussed.

The Bloxsom air lock: a historical perspective

In 1950, Allan P. Bloxsom (1901-1991), a pediatrician at the St Joseph Hospital in Houston, introduced his positive pressure oxygen air lock (AL) for the delivery room resuscitation of the asphyxiated newborn. The infant's entire body was placed into a cylindrical steel chamber that was tightly sealed and infused with warmed humidified 60% oxygen. The positive pressure within the AL was cycled between 1 and 3 lb/in(2) at 1-minute intervals to simulate the intrauterine pressures during the second stage of labor. Bloxsom developed the AL device in response to his hypothesis that the contractions of labor help to "condition: the infant for extrauterine survival. Parmalee said that the AL "certainly locks the infant up, safe from meddlesome and unintelligent treatment." When clear plastic versions of the AL became commercially available, it received widespread use in delivery rooms and newborn nurseries throughout the United States. In 1953, Apgar and Kreiselman produced apnea in adult dogs using pentobarbital and a muscle relaxant, and found that the AL device was unsuccessful with the oxygenation and ventilation of the animals. In 1954, Townsend in Rochester, New York, reported on his experience with the AL in 150 premature infants. He concluded that the AL should be "more accurately referred to as an oxygenator" and that, "the truly apneic infant cannot be maintained in a acyanotic state by the AL." The AL was finally subjected to the scrutiny of a randomized, controlled clinical trial that was published in 1956. Reichelderfer and Nitowski at Johns Hopkins randomized 171 infants to receive care in the AL or in an Isolette. Routine resuscitation, including positive pressure ventilation, was administered, as needed, to both study groups before placement into the AL or Isolette (Air Shields Inc, Hatboro, PA). They did not find any differences in the outcomes of the 2 study groups. By the mid 1950s, new information linking oxygen therapy and retrolental fibroplasia, led to a rapid decline in the use of the AL, even before the publication of the randomized trial.

Phototherapy--traditional and nontraditional

An observation by an English nurse in 1956 led to the discovery that visible light could lower serum bilirubin levels in newborn infants, and subsequent research showed how photons of light energy are absorbed by the bilirubin molecule converting it into isomers that are readily excreted by the liver and the kidney. Understanding the dose-response effect and other factors that influence the way light works to lower bilirubin levels has led to the effective use of phototherapy and has eliminated the need for exchange transfusion in almost all jaundiced infants.

Prediction of hyperbilirubinemia in near-term and term infants

OBJECTIVE

The purpose of this study was to determine whether end-tidal carbon monoxide (CO) corrected for ambient CO (ETCOc), as a single measurement or in combination with serum total bilirubin (STB) measurements, can predict the development of hyperbilirubinemia during the first 7 days of life.

METHODS

From nine multinational clinical sites, 1370 neonates completed this cohort study from February 20, 1998 through February 22, 1999. Measurements of both ETCOc and STB were performed at 30+/-6 hours of life; STB also was measured at 96+/-12 hours and subsequently following a flow diagram based on a table of hours of age-specific STB. An infant was defined as hyperbilirubinemic if the hours of age-specific STB was greater than or equal to the 95th percentile as defined by the table at any time during the study.

RESULTS

A total of 120 (8.8%) of the enrolled infants became hyperbilirubinemic. Mean STB in breast-fed infants was 8.92+/-4.37 mg/dl at 96 hours versus 7.63+/-3.58 mg/dl in those fed formula only. The mean ETCOc at 30+/-6 hours for the total population was 1.48+/-0.49 ppm, whereas those of nonhyperbilirubinemic and hyperbilirubinemic infants were 1.45+/-0.47 and 1.81+/-0.59 ppm, respectively. Seventy-six percent (92 of 120) of hyperbilirubinemic infants had ETCOc greater than the population mean. An ETCOc greater than the population mean at 30+/-6 hours yielded a 13.0% positive predictive value (PPV) and a 95.8% negative predictive value (NPV) for STB > or =95th percentile. When infants with STB > or =95th percentile at <36 hours of age were excluded, the STB at 30+/-6 hours yielded a 16.7% PPV and a 98.1% NPV for STB >75th percentile. The combination of these two measurements at 30+/-6 hours (either ETCOc more than the population mean or STB >75th percentile) had a 6.4% PPV with a 99.0% NPV.

CONCLUSIONS

This prospective cohort study supports previous observations that measuring STB before discharge may provide some assistance in predicting an infant's risk for developing hyperbilirubinemia. The addition of an ETCOc measurement provides insight into the processes that contribute to the condition but does not materially improve the predictive ability of an hours of age-specific STB in this study population. The combination of STB and ETCOc as early as 30+/-6 hours may identify infants with increased bilirubin production (eg, hemolysis) or decreased elimination (conjugation defects) as well as infants who require early follow-up after discharge for jaundice or other clinical problems such as late anemia. Depending on the incidence of hyperbilirubinemia within an institution, the criteria for decision making should vary according to its unique population.

Prediction of hyperbilirubinemia in near-term and term infants

OBJECTIVE

The purpose of this study was to determine whether end-tidal carbon monoxide (CO) corrected for ambient CO (ETCOc), as a single measurement or in combination with serum total bilirubin (STB) measurements, can predict the development of hyperbilirubinemia during the first 7 days of life.

METHODS

From 9 multinational clinical sites, 1370 neonates completed this cohort study from February 20, 1998, through February 22, 1999. Measurements of both ETCOc and STB were performed at 30 +/- 6 hours of life; STB also was measured at 96 +/- 12 hours and subsequently following a flow diagram based on a table of hours of age-specific STB. An infant was defined as hyperbilirubinemic if the hours of age-specific STB was greater than or equal to the 95th percentile as defined by the table at any time during the study.

RESULTS

A total of 120 (8.8%) of the enrolled infants became hyperbilirubinemic. Mean STB in breastfed infants was 8.92 +/- 4.37 mg/dL at 96 hours versus 7.63 +/- 3.58 mg/dL in those fed formula only. The mean ETCOc at 30 +/- 6 hours for the total population was 1.48 +/- 0.49 ppm, whereas those of nonhyperbilirubinemic and hyperbilirubinemic infants were 1.45 +/- 0.47 ppm and 1.81 +/- 0.59 ppm, respectively. Seventy-six percent (92 of 120) of hyperbilirubinemic infants had ETCOc greater than the population mean. An ETCOc greater than the population mean at 30 +/- 6 hours yielded a 13.0% positive predictive value (PPV) and a 95.8% negative predictive value (NPV) for STB >/=95th percentile. When infants with STB >95th percentile at <36 hours of age were excluded, the STB at 30 +/- 6 hours yielded a 16.7% PPV and a 98.1% NPV for STB >75th percentile. The combination of these 2 measurements at 30 +/- 6 hours (either ETCOc more than the population mean or STB >75th percentile) had a 6.4% PPV with a 99.0% NPV. Conclusions. This prospective cohort study supports previous observations that measuring STB before discharge may provide some assistance in predicting an infant's risk for developing hyperbilirubinemia. The addition of an ETCOc measurement provides insight into the processes that contribute to the condition but does not materially improve the predictive ability of an hours of age-specific STB in this study population. The combination of STB and ETCOc as early as 30 +/- 6 hours may identify infants with increased bilirubin production (eg, hemolysis) or decreased elimination (conjugation defects) as well as infants who require early follow-up after discharge for jaundice or other clinical problems such as late anemia. Depending on the incidence of hyperbilirubinemia within an institution, the criteria for decision making should vary according to its unique population.

Less aggressive treatment of neonatal jaundice and reports of kernicterus: lessons about practice guidelines

The publication of guidelines calling for less aggressive treatment of jaundice in newborns has been followed by a reappearance of case reports of kernicterus. These case reports illustrate important issues for writers and consumers of practice guidelines. One issue is the particular salience of identified patients with bad outcomes, and their potentially disproportionate influence on decision-makers. A second issue is whether, when good evidence of treatment benefit is lacking, policymakers should recommend what has traditionally been done, recommend less treatment, or not make recommendations at all. Finally, the cases raise the question of whether treatment guidelines should be more conservative than their authors actually believe is necessary, to take into account the likelihood that they will not be closely followed. We believe that case reports can serve as an important early warning system, but policymakers should be aware of their potentially disproportionate influence. In the long run, patients and clinicians will be best served by guidelines that summarize and acknowledge the limitations of existing evidence, that allow a wide range of treatment options when evidence is weak, and that recommend what the guideline authors actually believe should be done. In the short run a period of readjustment may be required, however, as clinicians become accustomed to guidelines written to be followed, rather than bent.

Changing partners: the dance of infant formula changes

The purpose of the study was to establish the frequency of, reasons for, and outcome of formula changes in infants. In this survey, we interviewed a convenience sample of 100 parents in our pediatric outpatient clinic and 75 parents in private pediatric office practices regarding their baby's initial formula, changes in formula, age at change, reason for change, initiator of the change, and outcome. The infants were 30-210 days old. Sixteen of the 175 infants (9%) were started on nonstandard formulas at birth. Fifty-eight of the remaining 159 infants (36%) were changed from regular to nonstandard formulas. After using nonstandard formulas, only seven infants (4%) were ever challenged subsequently with regular formula and all did well. Colic and regurgitation were the main reasons for switching formulas. In 47% the decision to change the formula was made by the mother and in 44% by the pediatrician. Following the formula change, mothers reported improvement or complete resolution of symptoms in 80% of infants. Although published estimates of formula intolerance range from 2% to 7.5%, one in three infants experiences a formula change, suggesting that nonstandard formulas are used excessively by both mothers and physicians. Nevertheless, in the vast majority of cases, parents report that the changes result in improvement or resolution of symptoms. Thus, while this practice appears to be a simple and effective intervention, it produces a significant population of soy and other nonstandard formula-fed babies who should be drinking regular formulas. Such changes encourage a belief by parents that their infants are allergic or otherwise abnormal and could have a negative impact on subsequent child development.

Bilirubin levels and severe retinopathy of prematurity in infants with estimated gestational ages of 23 to 26 weeks

Oxidative injury may contribute to the development of retinopathy of prematurity (ROP), and bilirubin may be a physiologically important antioxidant. Therefore we evaluated the relationship of ROP to bilirubin levels in 157 infants born at 23 to 26 weeks estimated gestational age. We found no definite association between bilirubin levels and severe ROP.

Capillary refill time in the hands and feet of normal newborn infants

We measured capillary refill time (CRT) in a convenience sample of 137 healthy newborns between 1 and 120 hours of age and 36-42 weeks gestation in the well-baby nursery of a large community hospital. CRT was measured by applying moderate pressure to the dorsum of the right hand and right foot for 5 seconds. Pressure was released and the time for complete refilling of the blanched area noted. Each infant was studied only once. We also measured ambient temperature and the skin temperature of the dorsum of the hand and foot and tested interobserver agreement. Mean CRT was 4.23 +/- 1.47 s (SD) range 1.63-8.78 s) in the hand and 4.64 +/- 1.41 s (range 2.15-9.94 s) in the foot (p = 0.0001) and did not change significantly in the first 72 hours. CRT decreased with increasing temperature. Environmental temperature, axillary temperature, and temperature of the hand and foot were all significantly and indirectly related to CRT, the strongest relationship existing between CRT and the skin temperature of the hand (r = -0.59, 95% CI -0.69, -0.47 p < 0.00001) and foot (r = -0.33, 95% CI -0.46, -0.16 p < 0.0001). With triplicate measurements, there was a statistically significant, but clinically moderate, order effect, CRT decreasing with each successive measurement (p < 0.0001). Interobserver agreement was fair, the correlation coefficient (r) ranged from 0.47 to 0.71. We conclude that CRT as measured in the hand or foot of a newborn infant in the first 5 days of life is a relatively subjective measurement with an endpoint that is not easy to define and a wide range of values in normal infants. It is influenced significantly by environmental, axillary, and skin temperatures. Since there is no accepted standard for measuring decreased perfusion in the newborn, it is impossible to document the clinical utility of CRT in this population. Further studies are necessary before CRT can be accepted as a useful measure of peripheral perfusion and circulatory status in the newborn infant.

Jaundice in full-term and near-term babies who leave the hospital within 36 hours. The pediatrician's nemesis

There has been an increase in hyperbilirubinemia in the newborn population and, perhaps, an increase in bilirubin encephalopathy. The early discharge of newborns from hospital has made it necessary for us to reorient our thinking about bilirubin levels in the first 24 to 48 hours of life and alter our approach to follow-up. The pediatrician must evaluate and follow infants who have risk factors for the development of severe hyperbilirubinemia, paying particular attention to the breast-feeding, near-term infant.

Length of stay, jaundice, and hospital readmission

OBJECTIVE

To evaluate the effect of postnatal age at the time of discharge on the risk of readmission to hospital with specific reference to readmission for hyperbilirubinemia.

DESIGN

Case-control study based on chart review.

SETTING

Large suburban community hospital in southeastern Michigan, delivering more than 5000 infants annually.

PATIENTS

Newborn infants, born between December 1, 1988, and November 30, 1994, who were readmitted to hospital within 14 days of discharge, were compared with a randomly selected control group who were not readmitted.

RESULTS

Of 29,934 infants discharged, 247 (0.8%) were readmitted by the age of 14 days. One hundred twenty-seven (51%) were admitted because of hyperbilirubinemia and 74 (30%) with the diagnosis of "rule out sepsis." The factors associated with an increased risk of readmission to the hospital were: infant of diabetic mother [odds ratios (OR), 3.45; 95% confidence limits (CL), 1.39 to 8.60]; gestation < or = 36 weeks (OR, 4.56; CL, 1.45 to 14.33), and 37 1/7 to 38 weeks (OR, 2.95; CL, 1.63 to 5.35) versus > or = 40 weeks; presence of jaundice in the nursery (OR, 1.73; CL, 1.14 to 2.63); breastfeeding (OR, 1.78; CL, 1.13 to 2.81); male sex (OR, 1.58; CL, 1.07 to 2.34); length of stay < 48 hours (OR, 1.91; CL, 1.15 to 3.16) and 48 to < 72 hours (OR, 2.09; CL, 1.25 to 3.50) versus > or = 72 hours. Factors associated with readmission for jaundice were gestation < or = 36 weeks (OR, 13.2; CL, 2.70 to 64.6), 36 1/7 to 37 weeks (OR, 7.7; CL, 2.69 to 22.0), 37 1/7 to 38 weeks (OR, 7.2; CL, 3.05 to 16.97) versus > or = 40 weeks; jaundice during nursery stay (OR, 7.80; CL, 3.38 to 18.0); length of stay < 48 hours (OR, 2.40; CL, 1.09 to 5.30) and 48 to < 72 hours (OR, 3.15; CL, 1.40 to 7.09) versus > or = 72 hours; male sex (OR, 2.89; CL, 1.46 to 5.74); and breastfeeding (OR, 4.21; CL, 1.80 to 9.87). Infants whose length of stay was < 48 hours were at no greater risk for readmission for jaundice or other causes than those whose length of stay was > or = 48 hours to < 72 hours.

CONCLUSIONS

Discharge at any time < 72 hours significantly increases the risk for readmission to hospital and the risk for readmission with hyperbilirubinemia when compared with discharge after 72 hours. The American Academy of Pediatrics recommends that infants discharged < 48 hours should be seen by a health care professional within 2 to 3 days of discharge. Our observations, as well as those of others, suggest that this recommendation should also be extended to those discharged at < 72 hours after birth. One approach to decreasing the risk of morbidity and readmission, particularly from hyperbilirubinemia, would be to help mothers to nurse their infants more effectively from the moment of birth.

Early discharge from the newborn nursery-effect on scheduling of follow-up visits by pediatricians

OBJECTIVE

To evaluate the impact of shorter hospital stays on the follow-up scheduling of newborn infants by private pediatricians.

DESIGN

Five surveys over a period of 18 months with educational intervention.

SETTING

Large community hospital well baby nursery.

PARTICIPANTS

Twenty private pediatricians who cared for at least 20 newborn infants in the well baby nurseries during 1995.

INTERVENTION

Oral and written communications to pediatricians emphasizing the importance of evaluating infants within 2 to 3 days of discharge if the hospital stay was less than 48 hours.

MAIN OUTCOME MEASURE

Interval between discharge from the nursery and the scheduled follow-up visit to the pediatrician.

RESULTS

In the first two surveys (September 1994 and March 1995) there was no significant difference in follow-up scheduling by pediatricians for those infants discharged <48 hours vs >/=48 hours. Differences were significant in July and November 1995, and in the final survey in March 1996. Nevertheless, in March 1996, 38% of short-stay infants were scheduled to be seen 4 or more days after discharge, and 33% 14 days after discharge.

CONCLUSION

Although follow-up practices have changed in response to shorter newborn hospital stays, a significant proportion of pediatricians are not following the American Academy of Pediatrics guidelines for the follow-up of short-stay infants. Whether or not failure to follow these guidelines will lead to an increase in morbidity is unknown.