Description of the condition

Jaundice is the yellow discolouration of the skin caused by the presence of bilirubin in the soft tissues and can result from high levels of conjugated or unconjugated bilirubin.  About 97% of full term and preterm neonates demonstrate a biochemical hyperbilirubinaemia (serum bilirubin level > 1 mg/dl) and about 65% appear clinically jaundiced (serum bilirubin > 5 mg/dl) (Maisels 1986; Keren 2008). Physiological jaundice results from a high level of circulating unconjugated bilirubin due to accelerated red cell break‐down, reduced liver bilirubin handling capacity and increased enterohepatic circulation (Horn 2006). Pathologic jaundice results from conditions such as haemolytic disease of the newborn, sepsis, and inborn errors of metabolism (Maisels 2005). Supplementary feeding, percentage weight loss, ABO incompatibility and vacuum extraction significantly increase the risk of jaundice (Bertini 2001).

Untreated indirect hyperbilirubinaemia may result in kernicterus. In the acute phase, the signs of kernicterus are poor feeding, lethargy, high‐pitched cry, hypertonia or hypotonia, opisthotonos and seizures. The chronic manifestations of kernicterus include athetoid cerebral palsy, motor delay, gaze palsy, dental dysplasia, mental retardation and sensorineural hearing loss. When neurological signs are evident in the infant, permanent damage has already occurred, leading to death or long‐ term disability (AAP 2004).

Description of the intervention

In 1985, the National Institute of Child Health and Human Development (NICHHD) reported that phototherapy was as effective as exchange transfusion in preventing neurological sequelae (NICHHD 1985). Since then, phototherapy has been widely adopted as the initial therapy of choice for neonatal jaundice (Knudsen 1991; Eberhard 1994). Phototherapy converts the bilirubin through structural photoisomerization and photo‐oxidation into excretable products. This molecular conversion occurs when bilirubin accumulating in the skin is exposed to light of wave‐lengths 425 ‐ 475 nm (blue‐green spectrum).The effectiveness of phototherapy is related to the area of skin exposed, the radiant energy, the sources and wave‐length of the light (Tan 1982; Thaithumyanon 2002), and the cause and severity of jaundice (Maisels 2008). The guidelines or protocols used to determine the need for phototherapy may vary from one study to the other. Lewis et al showed that early institution of phototherapy produced a more rapid decline in serum bilirubin levels compared to delayed phototherapy (Lewis 1982).

Side effects of phototherapy include temperature instability manifesting as either hyperthermia or hypothermia, dehydration (Oh 1972), gastrointestinal hypermotility, diarrhoea, drowsiness, and exanthemata (Knudsen 1991). Phototherapy has been linked to persistent ductus arteriosus (Clyman 1978; Rosenfeld 1986; Travadi 2006) and to increased incidence of atypical melanocytic naevi (Csoma 2007; Bauer 2004).

Continuous phototherapy involves maintaining the jaundiced neonate under phototherapy virtually all the time with only minimal interruptions (e.g. during feeding or cleaning) so as to maximize the time spent under radiant energy and hopefully minimize the duration of phototherapy and hospital stay. Intermittent phototherapy involves regular cessation of phototherapy at specific times and for specific duration to reduce exposure to radiant energy and allow ample time for parental‐infant interaction. There is no optimal time schedule for intermittent phototherapy defined in the literature and, therefore, different studies have looked at various time intervals for their effectiveness at lowering serum bilirubin while allowing ample time for parental‐infant interaction. A study by Vogl et al looked at three different intermittent schedules: fifteen minutes on and 15 minutes off phototherapy; 15 minutes on and 30 minutes off phototherapy; 15 minutes on and 60 minutes off phototherapy (Vogl 1978). A study by Hodgman looked at 12 hours on and 12 hours off phototherapy (Hodgman 1976). Jahrig et al also considered 12 hours on and 12 hours off phototherapy (Jahrig 1982).

The advantages and disadvantages of intermittent and continuous phototherapy remain controversial. Rubaltelli et al showed that continuous phototherapy was more effective than intermittent therapy in newborns greater than three days of age (Rubaltelli 1978). Rudenko and Kalinicheva showed that continuous phototherapy had the highest efficacy in prematures that was enhanced with the addition of alpha‐tocopherol acetate (Rudenko 1990). The study by Hodgman comparing intermittent versus continuous therapy showed that continuous phototherapy was more effective but was associated with higher metabolic demands (Hodgman 1976).

Other studies have supported the use of various schedules of intermittent phototherapy. Vogl et al showed that intermittent phototherapy was as effective as continuous phototherapy (Vogl 1978). Wu et al demonstrated that the subsequent catch‐up growth, after initial weight loss, was better in the intermittent compared to the continuous therapy group (Wu Py 1974). Roll observed that there was a marked reduction in the total light energy required to decrease serum bilirubin by a certain concentration. The ''dark periods'' of the intermittent therapy would allow for evaluation of the neonates’ skin colour, reduce stray light exposure to staff or parents, and facilitate feeding and parent‐child bonding. Increased apoptosis and necrosis was noted with longer exposure periods and was possibly due to increased photo‐oxidation and cell damage (Roll 2005).

Komar‐Szymborska et al showed that  the effectiveness of phototherapy depended on the initial bilirubinaemia and was similar in both continuous and intermittent groups (Komar‐Szymborska 1994). Intermittent therapy is convenient and best suited for home phototherapy in infants with no major risk factors (CIGNA 2008). Lau and Fung in their study noted that the chief advantage of intermittent treatment is the reduction of total irradiance. It was also simple and economically attractive for developing countries where the need is great and the resources are scarce (Lau 1984).

Why it is important to do this review

There is no consensus on whether intermittent phototherapy or continuous phototherapy is the preferred method of treatment. Intermittent therapy would be simple, economical, facilitate adequate feeding and bonding, home therapy, and have minimal adverse effects (Lau 1984; Roll 2005). Therefore, the aim of this review is to systematically assess the available evidence from randomized and quasi‐randomized controlled trials for the effect of intermittent phototherapy compared to continuous phototherapy in reducing the incidence of kernicterus and treatment failure.