Efficacy of phototherapy in non-haemolytic hyperbilirubinaemia

Efficacy of bidirectional fiber-optic phototherapy for neonatal hyperbilirubinemia

OBJECTIVE

To evaluate the efficacy of fiber-optic phototherapy using the standard Ohmeda Biliblanket, a large version, double standard Biliblankets, and conventional phototherapy using daylight fluorescent lamps in full-term, healthy infants with nonhemolytic hyperbilirubinemia.

METHODS

Full-term, healthy infants with nonhemolytic hyperbilirubinemia (bilirubin concentration, >255 micromol/L or 222 micromol/L at <48 hours of age) were allocated randomly to one of four modes of phototherapy: standard fiber-optic mat (Ohmeda Biliblanket), a large version, double standard Biliblankets, and conventional phototherapy. Bilirubin levels were monitored every 12 hours. Exposure was stopped when bilirubin levels were less than 185 micromol/L, the minimum duration being 24 hours.

RESULTS

A total of 171 infants were studied; 42 were exposed to standard fiber-optic phototherapy, 43 to large fiber-optic phototherapy, 42 to double-fiber-optic phototherapy, and 44 to conventional phototherapy. Durations of exposure were 87.05 +/- 6.09 (SEM), 82.57 +/- 5.84, 64.85 +/- 5.43, and 62.61 +/- 3.74 hours, respectively; the 24-hour decline rates were 10.26% +/- 1.84%, 14. 50% +/- 1.53%, 21.82% +/- 1.71%, and 19.00% +/- 1.65%, respectively; the overall decline rates over the whole exposure period were 0.47% +/- 0.03%, 0.52% +/- 0.04%, 0.71% +/- 0.05%, and 0.75% +/- 0.04% per hour, respectively. The efficacy of double-fiber-optic phototherapy and conventional phototherapy was similar and significantly better than that of the large fiber-optic mat and the standard fiber-optic mat in duration, 24-hour decline rate, and overall decline rate. The large mat was slightly better than the standard-size mat with regard to 24-hour decline rate and overall decline rate, but this difference was not significant. Failure of phototherapy occurred only in the large fiber-optic mat group (3 of 43) and the standard fiber-optic mat group (4 of 42); none occurred in the other two groups, but differences not statistically significant. The nursing personnel were more comfortable with single fiber-optic phototherapy, which caused no initial disturbance to the swaddled infants as did conventional phototherapy, but found double-fiber-optic phototherapy difficult to use.

CONCLUSION

For efficacy of fiber-optic phototherapy in full-term infants to be comparable to that of our conventional phototherapy, the light dose of the standard mats needs to be doubled.

Effect of phototherapy on thyroid stimulatory hormone and free thyroxine levels

OBJECTIVE

To study the effect of phototherapy for neonatal hyperbilirubinaemia on thyroid function as neonatal thyroid screening is sometimes performed during exposure to phototherapy.

METHODOLOGY

Infants with non-haemolytic hyperbilirubinaemia were sequentially allocated to fibre-optic phototherapy, conventional daylight phototherapy, or a combination of both. Bilirubin concentration was monitored 12 hourly by capillary blood sampling; venous blood was sampled for thyroid stimulating hormone (TSH) and free thyroxine (fT4) determinations, at start of exposure, at 24 h, end of exposure and 1 day later. Comparable unexposed infants served as controls.

RESULTS

All 123 study infants and 25 controls remained well during the study. Bilirubin levels declined during phototherapy, being most rapid in the combination group. The TSH and fT4 values at start of exposure were 3.86 +/- 0.41 mU/L (mean +/- SEM) and 33.20 +/- 1.16 pmol/L, respectively, in the fibre-optic group, 3.62 +/- 0.38 mU/L and 37.22 +/- 1.76 pmol/L in the daylight group, and 4.40 +/- 0.48 mU/L and 29.91 +/- 1.13 pmol/L in the combined group, compared with 5.77 +/- 0.40 mU/L and 34.46 +/- 1.68 pmol/L in the control group. The TSH and fT4 values declined with increasing age in the phototherapy and control groups with end of exposure values of 2.90 +/- 0.28 mU/L and 27.71 +/- 0.71 pmol/L, 2.77 +/- 0.31 mU/L and 33.52 +/- 1.22 pmol/L, and 3.44 +/- 0.30 mU/L and 27.54 +/- 0.88 pmol/L, respectively, compared with 4.21 +/- 0.61 mU/L and 27.19 +/- 2.33 pmol/L (at 72 h) in the control group. The pattern of TSH and fT4 decline in the exposed and control groups was similar, being related to increasing age.

CONCLUSIONS

The validity of neonatal thyroid screening is not affected by fibre-optic or conventional phototherapy or by both combined.

Phototherapy for neonatal jaundice

Exchange transfusion for severe neonatal jaundice is a tedious and expensive procedure with high morbidity and mortality rates, and is followed by a prompt and marked bilirubin rebound. It has largely been replaced by phototherapy, which though more gradual in its effect results in a prolonged reduction of the bilirubin concentration. Its efficacy is influenced by the gestational age, birthweight and postnatal age of the infant, the aetiology of the jaundice, and the spectral emission and intensity (dose) of the light; its dose-response relationship enables it, at the optimal dose, to control very severe jaundice or a rapidly rising bilirubin concentration, including severe haemolysis. Its relative freedom from complications together with its non-invasive nature, ease of usage and convenience has resulted in widespread acceptance in virtually all neonatal units.

Phototherapy for neonatal jaundice in infants with cephalhematomas

The efficacy of phototherapy in a group of infants with nonhemolytic hyperbilirubinemia and no cephalhematomas was compared with a second group of infants with large cephalhematomas (> 7 cm across), but similar in all other aspects. The cephalhematoma group demonstrated significantly lower hemoglobin (Hb) and hematocrit (hct) values (P < .0001, P < .002 respectively) than the standard group, even after the latter group had been adjusted by stratification (P < .0001, P < .005) such that the starting bilirubin concentration, birth weight, and gestational age were highly comparable to the cephalhematoma group. The bilirubin concentrations of the cephalhematoma, original, and adjusted groups were 277.8 +/- 5.8 mumol/L (16.24 +/- 0.03 mg/dL), [mean +/- sem], 265.2 +/- 0.5 mumol/L (15.50 +/- 0.03 mg/dL), and 275.2 +/- 0.9 mumol/L (16.09 +/- 0.05 mg/dL), respectively. The postnatal age at the start of phototherapy in the cephalhematoma group was comparable with that of the standard group before and after adjustment. Phototherapy was equally effective in the cephalhematoma and standard (original and adjusted) groups of infants, in terms of duration, 24-hr decline, and overall decline/hr for the duration of exposure. The proportionate 24-hr decline was 24.02 +/- 1.90% vs 20.99 +/- 0.23% and 22.61 +/- 0.48% and overall decline/hr was 0.83 +/- 0.06% vs 0.74 +/- 0.01% and 0.78 +/- 0.01%. We conclude that the sequestrated blood in the cephalhematomas did not significantly interfere with the efficacy of phototherapy.

Comparison of the efficacy of fiberoptic and conventional phototherapy for neonatal hyperbilirubinemia

A comparative evaluation of the efficacy of fiberoptic phototherapy using the Ohmeda Billiblanket fiberoptic device, conventional phototherapy using daylight fluorescent lamps, and a combination of the two forms of phototherapy was made in 165 term healthy infants and 105 preterm infants with hyperbilirubinemia. In the term infants, the 24-hour decline rate for fiberoptic phototherapy was 9.2% +/- 1.6% (mean +/- SEM) versus 21.5% +/- 1.8% for daylight phototherapy (p < 0.01), and the overall decline rate was 0.49% +/- 0.03%/hr versus 0.70% +/- 0.04%/hr (p < 0.001). Combination phototherapy, with a 24-hour decline rate of 29.9% +/- 1.0% and an overall decline rate of 0.97% %/- 0.04%/hr, was significantly better than daylight phototherapy in both respects (p < 0.01 and < 0.01, respectively). The duration of exposure for fiberoptic phototherapy was significantly longer than that for daylight phototherapy, which in turn was significantly longer than that for combination phototherapy. Response to exposure in the preterm infants was significantly better than that in the term infants with the respective types of phototherapy. The nursing personnel unanimously felt more comfortable with fiberoptic phototherapy, which did not disturb the swaddled infants as much as conventional phototherapy. The parents also felt more reassured. Fiberoptic phototherapy proved adequate in controlling hyperbilirubinemia in preterm infants; in term infants, failures often occurred. Combination phototherapy can be recommended for severe or rapidly increasing jaundice in preterm infants, but its efficacy in term infants is uncertain.

Efficacy of phototherapy in neonatal hyperbilirubinaemia associated with glucose-6-phosphate dehydrogenase deficient status

The efficacy of phototherapy in a group of 427 infants with hyperbilirubinaemia associated with glucose-6-phosphate dehydrogenase (G6PD) deficiency and a comparable group of 3924 G6PD normal infants with non-haemolytic hyperbilirubinaemia was evaluated. Phototherapy was highly effective in reducing bilirubin levels in both groups of infants, being significantly more effective in the group with normal G6PD status. Failure rate was very low (2.03/1000) in the group with normal G6PD status and nil in the G6PD deficient group. Bilirubin rebound after phototherapy was unremarkable with very few infants requiring a second exposure--4.68/1000 in the G6PD deficient group and 6.37/1000 in the G6PD normal group. All the babies tolerated phototherapy well. Phototherapy would therefore seem to be a simple and effective method for the management of severe jaundice associated with G6PD deficiency.

Phototherapy for neonatal nonhemolytic hyperbilirubinemia. Analysis of rebound and indications for discontinuing therapy

Phototherapy, an effective treatment for neonatal indirect hyperbilirubinemia, has guidelines for its initiation but none for its discontinuation. In our study, phototherapy was begun at a mean age of 90 hours in 28 full-term and 30 preterm infants with indirect nonhemolytic hyperbilirubinemia. After three days, phototherapy was halted at a mean bilirubin concentration of 13.0 +/- 0.7 mg/dL in term and 10.7 +/- 1.2 mg/dL in preterm infants, levels higher than those used by other investigators. Bilirubin rebound then occurred at a mean of 12.5 hours to a level of 0.86 +/- 1.0 mg/dL in term and at a mean of 14.1 hours to a level of 0.83 +/- 0.56 mg/dL in preterm infants. No complications were observed nor was there a need for reinstitution of phototherapy. Based on these data, discontinuation of phototherapy at higher bilirubin concentrations and earlier home discharge than previously described appear harmless for both term and preterm neonates.

Efficacy of "high-intensity" blue-light and "standard" daylight phototherapy for non-haemolytic hyperbilirubinaemia

We report our clinical experience with phototherapy in 3802 infants; 3629 were exposed to "standard" daylight phototherapy and 173 to "high-intensity" blue-light phototherapy. High-intensity blue-light phototherapy was twice as effective as standard daylight phototherapy in decreasing bilirubin concentrations. No failures occurred with high-intensity phototherapy compared with an overall failure rate of 1.84/1000 with daylight lamps; these cases were transferred to high-intensity phototherapy with prompt response. Rebound after cessation of phototherapy was greater in those exposed to high-intensity blue light with a significantly greater number requiring a second exposure. However, the incidence was still low. No third exposure was required in any infant. Nursing of infants under high-intensity blue light was more difficult and inconvenient as was clinical monitoring. The light also caused more stress on the nursing and medical personnel. However, the infants tolerated both types of phototherapy equally well. High-intensity blue-light phototherapy would seem to be the treatment of choice for infants with rapidly increasing or very high bilirubin levels, as well as in those not responding adequately to daylight phototherapy.

Efficacy of fluorescent daylight, blue, and green lamps in the management of nonhemolytic hyperbilirubinemia

The efficacy of fluorescent daylight, green, and blue lamps in reducing bilirubin levels was compared in two groups of infants with nonhemolytic hyperbilirubinemia: healthy infants in a term nursery and infants in an intensive care unit. The decline of serum bilirubin concentration was most rapid with the blue lamps, with the duration of exposure required being significantly shorter than that with the other two types of light in both groups. The rate of decline over the first 24 hours, as well as the overall rate of decline for the whole duration of phototherapy, was also significantly greater with the blue lamps, the rate being about twice that for the green lamps in the infants in the intensive care unit; the daylight lamps were intermediate in efficacy. The daylight lamps permitted easy clinical monitoring with minimal side effects, whereas the green and blue lamps were equally disturbing to the attending personnel. The green lamps caused severe erythema and tanning in the initial 200 hours of phototherapy. It appears preferable to use either daylight lamps, which permit enhanced clinical monitoring with adequate efficacy, or special blue lamps, which provide maximal therapeutic effect, rather than green lamps, which offer neither.