The belief of the restorative powers of fresh air and sunlight by a nurse in charge of a premature unit in a hospital in Essex, England in 1956 showed the way to the discovery of sunlight as treatment for jaundice infant thus lead to the invention of phototherapy devices to treat jaundice (Stokowski, 2006). Although sunlight helps in the treatment of jaundice, the American Academy of Pediatrics (AAP) (2004) mentions that the practice is not considered safe or reliable for jaundice treatment. Ultraviolet irradiation coming from sunlight and artificial therapeutic lamps possess toxic effects that we should be concern about (Matsumura and Ananthaswamy, 2003).
The writer is a staff nurse currently employed in a neonatal intensive care unit of a tertiary hospital. The aim of this essay is to critically appraise available literature pertaining to the efficacy of conventional phototherapy in the newborn with hyperbilirubinemia. Nurses in our unit depend on doctors on how many phototherapy devices we are suppose to expose the infant with elevated serum bilirubin levels. From the ordinary fluorescent lights to the fibre optic ones, we could not possibly determine which is most effective to be used in the treatment of hyperbilirubinemia. Majority of nurses know that it lowers bilirubin levels but without knowing what device suits best. Through research and evidence practice, data accumulated will be used in determining which technique or method produces greater positive result.
In this literature review, the writer will examine different studies on how to determine the efficacy of a phototherapy device, methods to enhance a phototherapy's irradiance and the manner which bilirubin react to light. The treatment approach will greatly affect patient care if nurses know how technical they are delivering phototherapy for the newborn. Continuous phototherapy may not be as effective as intermittent (Stephenson, 2000). Shortening the length of exposure to phototherapy means shortening hospitalization therefore the infant could spend more time with his or her parents (Djokomulijanto et al. 2006).
Articles used in this critical appraisal were mainly acquired using the electronic database CINAHL and Medline on EBSCOHOST, Cochrane, and PubMed. Search engines were also used particularly Google Scholar. Some articles were hand searched; others given by colleagues, medical books on hand and the hospital library were also employed. The search strategy utilized in search of the relevant literatures used the following keywords and phrases either combined or alone, phototherapy, hyperbilirubinemia, jaundice, efficacy, preterm and newborn. There are 886 articles leading to the topic thus limits were applied to the date of publication and language used, but 20 articles were used out of this limits due to the significance of its content. The literatures are classified as quantitative research, literature reviews and some are opinionated materials.
The framework for extracting information from research based literature (Appendix A) was used as a very useful tool in this review. After marking the articles' relevance to the review, the marking with higher ratings was given more emphasis.
It is estimated that neonatal jaundice is likely to occur in 60% of term newborns in the first week of life (Chou et al. 2003; Maisels and McDonagh, 2008). Hyperbilirubinemia is increased levels of the bile pigment in the blood with symptoms of jaundice, lack of appetite and fatigue (Glanze, 1996). Phototherapy is the use of visible light for the treatment of hyperbilirubinemia (Stokowski, 2006). The use of phototherapy is to reduce the increasing level of bilirubin to prevent exchange blood transfusion (Stephenson et al. 2000; Gomella et al. 2004). It converts bilirubin into products that can pass by the liver's conjugating system and be excreted to the bile or in the urine (Maisels, 2006). If delayed treatment or untreated, it might lead to a neurological disorder called kernicterus and may possibly affect the infant's development in the future.
The widely accepted choice for both controlling and preventing hyperbilirubinemia is phototherapy (Granati, 1983). Phototherapy is a simple treatment however, its application does not have a standard. Newman et al. (2009) contends that one gap in evidence in the use of phototherapy is the number needed to treat with phototherapy from the guidelines currently recommended. The factors to consider in determining it's efficacy according to Vreman et al. (2007) are the distance of the infant from the light, length of time to be exposed, body surface area to be treated, the severity of jaundice, and the phototherapy device itself.
Phototherapy evaluation was determined by the potency of the light (bandwidth and peak emission), the dose (irradiance or intensity) where light reaches the infant and the total body surface area (BSA) the light can treat (Vreman et al. 2007). In a level one nursery hospital in Malaysia, a randomized controlled trial clinical trial conducted by Djokomulijanto et al. (2006) was made. The study was made to determine the efficacy of phototherapy if used with white reflecting curtains. In this trial, 100 infants are included, 50 in each group and were randomized either to receive phototherapy with curtains on both sides or without the white curtains. The unit from the infant is set to 45cm as standard distance. The primary outcome measure is the decrease in bilirubin level 4 hours after the initiating phototherapy against the baseline. The secondary outcome measure is the length of time the infant is under phototherapy treatment. In the control group, 49 infants are allocated while 51 infants for the intervention group. 3 of the infants, 1 from the intervention group and 2 from the control group were exited in this study due to high levels of bilirubin close to the exchange transfusion level. If TSB levels nearly reaches or exceeds 12mg/dL, an exchange transfusion should be considered (Gomella et al. 2004).
In the intervention group the mean standard decrease of bilirubin after 4 hours is 27.62(25.24) µmol/l while for the control group is 4.04 (24.27) µmol/l (p<0.001). The median duration of phototherapy is 12 hours (25th quartile 7h, 75th quartile 14h ) in the intervention group and 34h(25th quartile 17h, 75th quartile 40h) for the control group.
The median duration of phototherapy for the intervention group is shorter by 22 hours compared to the control group. The mean standard deviation serum bilirubin level 24 hours after phototherapy was discontinued is not significantly different between the intervention and control group. This is in congruent with Tan (1982) study which demonstrates that further phototherapy after a decrease of 5mg/dL diminishes the efficacy of phototherapy. The infants do not need repeat phototherapy for rebound hyperbilirubinemia. None of the infants have temperature instabilities either hyperthermia or hypothermia. Significant weight lost was not also seen with the infants. All infants passed the otoacoustic emissions test on both ears. No neurodevelopmental abnormality was noted before the infants discharge.
Although the author made a good clinical trial, the writer believes that some key factors were omitted in this study. The author failed to mention if the infant was nursed in a double walled incubator or in an open cot. The use of 6 blue fluorescent bulbs is an uncommon combination seen in phototherapy units in the writer's workplace. Blue lights are discomforting for staff in hospitals because it causes nausea, headaches and dizziness (Levene et al. 1980). The use of blue and white combination of lights is less disturbing to staff and gives a better visual assessment of the infant.
DISTANCE FROM LIGHT
The American Association of Pediatrics Policy Statement on Jaundice (2004) states that the distance of the light source from an infant has a dramatic effect on the spectral irradiance, thus affecting treatment. It is possible to bring the infant as close as 10 cm to the fluorescent tubes (AAP, 2004). Maisels and McDonagh (2008) also states that "The dose and efficacy of phototherapy are also affected by the infant's distance from the light (the nearer the light source, the greater the irradiance)." Although the AAP (2004) established these guidelines, their recommendations do not indicate that it is a standard for medical care.
Stephenson et al. (2005) recommends that the ideal distance of the infant from the phototherapy unit is 45cm, if the infant is inside the isolette there should be a 5cm distance between the wall and phototherapy. The walls of the isolette will protect the infant from ultraviolet irradiation but not from the irradiation needed in treating hyperbilirubinemia (Stephenson et al. 2005). Recent studies outlined by Walker et al. (2007) suggest that delivering phototherapy treatment to a full term healthy infant in an isolette is not as effective as giving it in an open cot.
Further quantitative research should be made because the writer can not presently locate at the moment any study or research that used specific distance of the infant from the phototherapy unit as the factor showing the efficacy of the phototherapy lights.
EXPOSED BODY SURFACE AREA
In a qualitative study conducted by Granati (1983), he investigated the in vivo and in vitro relationship between the hematocrit (HCT) and the effectiveness of phototherapy and the varying effect of skin area exposed to light. For the first study of the in vitro effect of different HCT on bilirubin photodegeneration, they prepared 4 bilirubin solutions. These samples are exposed in blue lights for 24 hours in a 3 cm petri dish. The irradiation at the level of the solution is 22 µW/ cm²/ nm and the wavelength was between 425 and 475nm. The solution was then placed in a 20 incubator continuously agitated. After the incubation, the bilirubin concentration was measured. For the in vivo effect of different HCT on bilirubin photogeneration, 57 infants who had undergone phototherapy for development of nonhemolytic hyperbilirubinemia were utilized. The group is divided into two; each group is similar to age, sex, weight, gestational age, time of treatment, and baseline serum bilirubin level but differs in HCT during the phototherapy period. The mean HCT of the first group of 30 infants is 67 ±5% (60-74) while the HCT for the second group of 27 infants has a mean HCT of 50 ±5% (45-58), p < 0.01 using the student's t test.
The hyper viscous group did not manifest any significant symptoms related to cardiovascular, respiratory, gastro intestinal or central nervous system. After 24 hours of phototherapy 6 of the infants were treated prophylactically with partial exchange transfusion. The decision to perform or not to perform partial exchange transfusion was decided by a physician who is not involved in the study, and the physician's basis is the evaluation of clinical data. In the test involving multiple direction phototherapy versus single direction phototherapy, 20 full term infants with developmental jaundice (nonhemolytic hyperbilirubinemia) are divided into to groups. For the first group multiple direction phototherapy (MDP) was used. The phototherapy had an intensity of 22µW/cm²/nm at wavelengths of 425-475 nm located both below and above the level of the infant with initial serum bilirubin levels of 12.5 ±0.4mg/dl. On the second group the intensity is similar to the first group but only placed above the infant with baseline level of 12.8 ±0.5mg/dl.
The use of Photo-Ictometer was used in acquiring the bilirubin concentrations. To check the presence of metastable geometric isomers, the serum bilirubin solution is washed in the dark with chloroform and then the use of petroleum ether. The results show on the first study that bilirubin photodegradation is high if HCT is low. For the in vivo, there was no significant difference in the decline of bilirubin concentration for the high HCT group or normal HCT group. The results show that hematocrit does not influence the efficacy of phototherapy but the area of skin exposed to light does have a great contribution in the light treatment.
Bilirubin is absorbed toward longer wavelengths at around 475nm, and lights that have longer wavelengths penetrate deeper into the skin. Green lights may penetrate deeper into the skin with a photon of 510 nm but they have the possibility not to be absorbed by bilirubin (Rubaltelli, 2007). Bilirubin is absorbed beneath the skin in light treatments, since preterm infants have lesser skin layers compared to a term or near term infant, they have greater bilirubin absorption. This observation is confirmed by Montcrieff and Dunn (1976) where "Phototherapy seems to control the plasma bilirubin level satisfactorily in very low birth weight infants, but frequent measurements on the second or third day of life are advised."
This is in contrast with Pritchard's (2004) randomized control trial of preterm infants with birth weights greater than 1500g and less than or equal to 36 weeks gestational age were randomized to be nursed naked or partially clothed with only disposable nappies being used. 59 babies were included in this trial. 30 infants were assigned to the partially clothed group while the 29 were assigned in the naked group. These babies were exposed to conventional overhead phototherapy treatment with irradiance of 6µW/cm²/nm and wavelengths of 425-475nm, double walled isolettes and 35cm beneath the lamps. After 24 hours of treatment mean TSB for the group with nappies was 15.4% (while for the naked group was 19% () with a mean difference 3.6% 95% CI -5.1, 12.3. It is concluded that there is no significant difference in reducing total serum bilirubin levels using either practice.
It is also a common thing to cover the genitals of naked babies under phototherapy. Ennever (1990) claims that "The practice of covering the gonads of infants under phototherapy has little scientific basis." He claims that the amount of genotoxic irradiation received babies under phototherapy is only a fraction of the genotoxic irradiation an infant will receive for the first year of their life.
Different studies showed various results in trying to determine the efficacy of phototherapy in treating hyperbilirubinemia in the newborn. According to Pritchard et al. (2004), nursing the infant with or without nappies had no significant difference to decrease total serum bilirubin levels while Maisels (2006) claims that skin exposure is an important factor in improving the device's efficacy. The use of a white cloth around the cot in Djokomulijanto et al. (2006) study could possibly be the most simple efficient device attachment enabling the increase in a conventional phototherapy's efficacy. Although the results are promising, some other relevant situations in the NICU were not tested. Wentworth (2005) states that phototherapy devices are manufactured differently from each other and not all are effective. Care should be taken in considering what kind of phototherapy device to use. The combination of important criteria identified, the more informed decisions we make. Not all infants are the same hence their treatments may be considered in a case to case basis.
It would be a good and probably the best preference if a hospital or clinic will procure the best equipment out there. Being the best doesn't mean to be the most expensive equipment, but being the most efficient in trying to reduce bilirubin levels in infants.
There is no doubt that phototherapy is considered to be the primary choice in treating and preventing hyperbilirubinemia in the neonates (Vreman, 2008). Although research studies have proven that phototherapy decreases TSB levels, there is no specific numbers to treat hyperbilirubinemia. The AAP (2004) established a guideline but does not consider itself as the treatment regimen. After reading the articles on hand, the writer recommends that more quantitative research studies should be conducted particularly in measuring irradiance and serum bilirubin levels in various sites of the infant.
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