Local anaesthetic eye drops for prevention of pain in preterm infants undergoing screening for retinopathy of prematurity

Infants born less than 1500 g or less than 32 weeks are at increased risk of retinopathy of prematurity, a potentially blinding eye condition, and so have routine ophthalmological assessment. This process is a recognised source of pain and discomfort for preterm infants. This review highlights that retinopathy of prematurity is a painful examination and that instillation of local anaesthetic eyedrops immediately prior to examination of the eye is associated with a reduction in pain scores, as assessed by validated pain scores. Ongoing research is required to determine the optimum local anaesthetic eyedrop and other potentially important methods of reducing pain, including swaddling, and sucrose.

Authors' conclusions: 

The administration of topical proparacaine 30 seconds prior to the ophthalmological evaluation was associated with a reduction in pain scores especially at the time of speculum insertion. However, despite treatment, screening remains a painful procedure and the role of nonpharmacological and pharmacological intervention including different local anaesthetic agents should be ascertained in future randomised trials.

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Background: 

Screening examinations for retinopathy of prematurity (ROP) are performed routinely in the neonatal intensive care unit and are a recognised cause of pain in the newborn.

Objectives: 

To determine the effect of instillation of topical anaesthetic eye drops compared with placebo or no treatment on pain in infants undergoing ROP screening.

Search strategy: 

We used the standard search strategy of the Cochrane Neonatal Review Group. This included a search of the Cochrane Neonatal Group register and the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 10, 2010). We identified relevant studies by searching the following: (1) computerised bibliographic databases: MEDLINE (1966 to October 2010), EMBASE (1988 to October 2010) and Web of Science (1975 to March 2010; (2) the Oxford Database of Perinatal Trials. We searched electronically abstracts from PAS from 2000 to 2010 and handsearched abstracts from ESPR from 2000 to 2009.

Selection criteria: 

All randomised, or quasi-randomised controlled trials, or randomised cross-over trials.

Data collection and analysis: 

We used the standard methods of the Cochrane Neonatal Review Group.

Main results: 

We identified two studies for inclusion. Both studies were randomised cross-over trials performed in single centres. Both studies used the Premature Infant Pain Profile (PIPP) score as a measure of pain response. Different methods of evaluating PIPP scores are presented including the absolute PIPP score, a PIPP score > 10 or > 12 and an increase in PIPP ≥ 4 from the baseline value. There is a nonsignificant reduction in pain scores at one minute and a nonsignificant increase at five minutes post insertion of the speculum. PIPP score > 12 at one minute resulted in a statistically significant reduction in the number of patients who experienced pain (typical risk ratio (RR) 0.56, 95% CI 0.36 to 0.89; typical risk difference (RD) -0.23, 95% CI -0.39 to -0.86; number needed to treat to benefit (NNTB) 4). When pain was defined as an increase in PIPP > 4 there was a statistically significant reduction in the absolute number of patients who experienced pain at one minute (typical RR 0.70, 95% CI 0.52 to 0.94; typical RD -0.19, 95% CI -0.34 to -0.04; NNTB 5.3).

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