Background: Heel lance has been the conventional method of blood sampling in neonates for screening tests. Neonates undergoing this procedure experience pain. Despite various studies evaluating the role of pharmacological and non-pharmacological interventions to date, there are no effective and practical methods to alleviate pain from heel lance.
Objectives: To determine whether venepuncture or heel lance is less painful and more effective for blood sampling in term neonates.
Search strategy: Systematic search was performed in accordance with the Cochrane Neonatal Collaborative Review Group. Randomized controlled trials which compared pain response to venepuncture vs. heel lance were identified using MEDLINE (1966 - June 2007), EMBASE (1980 - June 2007), CINAHL (1982 - June 2007), Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 2, 2007), reference lists of identified trials and personal files. No language restrictions were applied.
Selection criteria: Randomized controlled trials which compared pain response to venepuncture vs. heel lance were selected for this review.
Data collection and analysis: Data regarding the primary outcome of pain response to venepuncture vs. heel lance as assessed by validated pain measures were abstracted. Secondary outcomes included the need of repeat blood sampling, bruising/hematoma at local site, and parental perception of their own anxiety and infant's pain. All data were analysed using RevMan 4.2.10. When possible, meta-analyses were performed using relative risk (RR) and risk difference (RD), along with their 95% confidence intervals (CI). If RD was significant, number needed to treat (NNT) was calculated. Weighted mean difference (WMD) was used for continuous data. When present, statistically significant between study heterogeneity was reported including the I squared (I(2) ) test.
Main results: Five trials were eligible for inclusion in the review (including one additional trial identified in this update). Pain assessments were made using validated pain measures including Neonatal Infant Pain Scale (NIPS), Neonatal Facial Action Coding System (NFCS), Premature Infant Pain Profile (PIPP) score and cry characteristics. Two trials did not report on outcomes for all enrolled infants (not intention to treat analyses). Despite the many different pain measures used, all studies showed statistically significantly lower pain scores for venepuncture as compared to heel lance. A meta-analysis of the NIPS scores during the first minute of the procedure (reported in two studies) was statistically significantly lower in the venepuncture group compared to the heel lance group [typical WMD -1.84 (95% CI -2.61, -1.06)]. There was no statistically significant heterogeneity for this outcome (p = 0.22; I(2) 33.3%). The typical RR for requiring more than one skin puncture for venepuncture vs. heel lance (reported in 4 studies) was 0.30 (95% CI 0.18, 0.49). The RD was -0.31 (95% CI -0.41, -0.22). For this outcome there was statistically significant between study heterogeneity (for RR, p = 0.02, I(2 )74.3%; for RD, p < 0.00001, I(2) 96.6%). The number needed to treat (NNT) to avoid one repeat skin puncture was 3 (95% CI 2, 5). In one study, maternal anxiety was noted to be higher in the venepuncture group as compared to heel lance group prior to the procedure; however, after observing the procedure, mothers rated their infant's pain to be lower in the venepuncture group.
Authors' conclusions: Venepuncture, when performed by a skilled phlebotomist, appears to be the method of choice for blood sampling in term neonates. For each three venepunctures instead of heel lance, the need for one additional skin puncture can be avoided.Further well designed randomized controlled trials need to be conducted. The interventions should be compared in settings where several individuals perform the venepuncture and/or the heel lance.