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 in accordance with Cochrane Neonatal Collaborative Review Group. All randomized controlled trials which compared pain response to venepuncture vs. heel lance were searched using MEDLINE, EMBASE, CINAHL, the Cochrane Library, 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 including the need of repeat blood sampling, bruising/hematoma at local site, and parental perception of their own anxiety and infant's pain were also abstracted. All data were analysed using RevMan 4.1. When possible, meta-analysis was done using relative risk (RR) and event rate difference (ERD), along with their 95% confidence intervals (CI). If ERD 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.
Main results: Three trials were eligible for inclusion in the review. 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. Despite the heterogeneity in the pain measures used, all studies showed statistically significantly lower pain scores for venepuncture as compared to heel lance. 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. A meta-analysis was performed on the need for at least one additional skin puncture to obtain the required amount of blood using venepuncture as compared to heel lance. The relative risk for requiring more than one skin puncture for venepuncture versus heel lance was 0.30 [95% confidence interval (CI) 0.18, 0.49]. The risk difference was -39% (95% CI -50%, -28%). For this outcome there was statistically significant between study heterogeneity (for RR, p=0.02; for RD, p=0.0001). The number needed to treat (NNT) to avoid one repeat skin puncture was 2.56 (95% CI 2, 3.57).
Reviewer's conclusions: Venepuncture, when performed by a trained phlebotomist, appears to be the method of choice for blood sampling in term neonates. For each two to three venepunctures instead of heel lance, the need for one additional skin puncture can be avoided. In view of the promising results derived from these small studies with some methodological limitations, including statistically significant between study heterogeneity, 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.