Get access

Cycled light in the intensive care unit for preterm and low birth weight infants

  • Review
  • Intervention

Authors


Abstract

Background

The potential benefits and harms of different lighting in neonatal units have not been quantified.

Objectives

To compare the effectiveness of cycled lighting (CL) (approximately 12 hours of light on and 12 hours of light off) with irregularly dimmed light or near darkness (ND) and with continuous bright light (CBL) on growth in preterm infants at three and six months of age.

Search methods

Electronic searches of the literature were conducted (in May 2010) of the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), MEDLINE, EMBASE, CINAHL and abstracts from Pediatric Academic Societies' annual meetings.

Selection criteria

Randomised or quasi-randomised trials of CL versus ND or CBL in preterm and low birth weight infants.

Data collection and analysis

Data collection and analyses were performed according to the methods of the Cochrane Neonatal Review Group.

Main results

Five studies enrolling 387 infants compared CL to ND. No study reported on weight at three or six months. In one study (n = 40) there was no statistically significant difference in weight at four months between the CL and the ND groups. In another study (n = 62) the ratio of day-night activity prior to discharge favoured the CL group (mean difference 0.18, 95% CI 0.17 to 0.19) indicating 18% more activity during day than night in the CL group compared to the ND group. Two studies (n = 189) reported on retinopathy of prematurity (stage ≥ 3). There was no statistically significant difference between the CL and ND groups (typical RR 0.53, 95% CI 0.25 to 1.11, I2 = 0%; typical RD -0.09, 95% CI -0.19 to 0.01, I2 = 0%).

Two studies enrolling 82 infants compared CL to CBL. One study (n = 41) reported higher mean weight at three months corrected age in infants cared for in the CL nursery (P < 0.02) and lower mean number of hours spent awake in 24 hours at three months (P < 0.005). In one study (n = 41) days on a ventilator were reduced in the CL group (mean difference -18, 95% CI -31 to -5 days).

For many outcomes the trends favoured CL versus ND as well as CL versus CBL.

Authors' conclusions

Trials assessing the effect of CL have enrolled 469 infants. Trends for many outcomes favoured cycled light (CL) compared to near darkness (ND) and CL compared to continuous bright light (CBL) The studies may have lacked significance due to a lack of statistical power. Future research should focus on comparing CL to ND.

Resumen

Antecedentes

Tratamiento con luz en ciclos en la unidad de cuidados intensivos para lactantes prematuros y de bajo peso al nacer

No se han cuantificado los posibles efectos beneficiosos y perjudiciales de distintos tipos de luz en las unidades neonatales.

Objetivos

Comparar la eficacia de la luz en ciclos (LC) (aproximadamente 12 horas con luz y 12 horas sin luz) con la luz irregularmente atenuada o la ausencia casi completa de luz (AL) y con luz brillante continua (LBC) en el crecimiento de lactantes prematuros a los tres y seis meses de vida.

Estrategia de búsqueda

Las búsquedas electrónicas en la literatura (en mayo 2010) se realizaron en el Registro Cochrane Central de Ensayos Controlados (Cochrane Central Register of Controlled Trials) (CENTRAL) (The Cochrane Library), MEDLINE, EMBASE, CINAHL y en los resúmenes de las reuniones anuales de las Pediatric Academic Societies.

Criterios de selección

Ensayos aleatorios o cuasialeatorios de LC versus AL o LBC en lactantes prematuros y de bajo peso al nacer.

Obtención y análisis de los datos

La extracción y los análisis de los datos se realizaron según los métodos del Grupo Cochrane de Neonatología (Cochrane Neonatal Review Group).

Resultados principales

Cinco estudios que incluyeron 387 lactantes compararon la LC con la AL. Ningún estudio informó sobre el peso a los tres o seis meses. En un estudio (n = 40) no hubo diferencias estadísticamente significativas en el peso a los cuatro meses entre los grupos LC y AL. En otro estudio (n = 62) el cociente de actividad díanoche antes del alta favoreció al grupo de LC (diferencia de medias 0,18; IC del 95%: 0,17 a 0,19), lo que indica una actividad 18% mayor durante el día que durante la noche en el grupo de LC en comparación con el grupo de AL. Dos estudios (n = 189) informaron retinopatía del prematuro (estadio ≥ 3). No hubo diferencias estadísticamente significativas entre los grupos LC y AL (RR típico 0,53; IC del 95%: 0,25 a 1,11; I2 = 0%; DR típica −0,09; IC del 95%: −0,19 a 0,01; I2 = 0%).

Dos estudios que incluyeron 82 lactantes compararon LC con LBC. Un estudio (n = 41) informó el peso medio mayor a los tres meses de edad corregida en los lactantes atendidos en la unidad de recién nacidos con LC (p < 0,02) y el número medio menor de horas despiertos en 24 horas a los tres meses (p < 0,005). En un estudio (n = 41) los días en un respirador se redujeron en el grupo de LC (diferencia de medias −18; IC del 95%: −31 a −5 días).

Para muchos resultados las tendencias favorecieron a la LC versus la AL, así como a la LC versus la LBC.

Conclusiones de los autores

Los ensayos que evaluaron el efecto de la LC incluyeron 469 lactantes. Las tendencias para muchos resultados favorecieron a la luz en ciclos (LC) comparada con la ausencia casi completa de luz (AL) y a la LC comparada con la luz brillante continua (LBC). Los estudios pueden haber carecido de significación debido a la falta de poder estadístico. Los estudios de investigación futuros se deben centrar en comparar la LC con la AL.

Traducción

Traducción realizada por el Centro Cochrane Iberoamericano

Plain language summary

Cycled light in the intensive care unit for preterm and low birth weight infants

The pregnant woman is exposed to variable intensities of lighting and sound and, in general, lower levels at night. Some of the lighting and sound reaches the fetus in the womb and induces circadian rhythms. Circadian is a term used to describe biological processes that recur naturally on a 24-hour basis. After birth, preterm infants are cared for in an environment that has no planned light-dark cycles or any other circadian entraining signals. Infants are exposed to either continuous bright light, continuous near darkness or an unstructured combination of the two. Our primary objective was to determine the effectiveness of cycled light (approximately 12 hours of light on and 12 hours of light off) on growth in preterm infants at three and six months corrected gestational age. To date fewer than 500 infants have been enrolled in trials assessing the effect of cycled light. One study reported improved growth at three months of age. One study found no difference in weight at four months of age. Only few outcomes reached statistical significance, likely due to the small number of infants enrolled in the studies, but trends for most outcomes (weight gain, length of stay, incidence of retinopathy of prematurity) favoured cycled light compared to near darkness and cycled light compared to continuous bright light.