Objective. A number of studies have shown that orally administered sweet-tasting solutions reduce signs of pain during painful procedures. The local anesthetic cream EMLA has recently been shown to be safe for use in neonates. This study compared the pain-reducing effect of orally administered glucose with that of EMLA cream during venipuncture in newborns.
Methods. Randomized, controlled, double-blind study including 201 newborns undergoing venipuncture for clinical purposes. Ninety-nine of the newborns received EMLA on the skin and orally administered placebo (sterile water), and 102 received glucose 30% orally and placebo (Unguentum Merck) on the skin. Symptoms associated with pain at venipuncture were measured with the Premature Infant Pain Profile (PIPP) scale (also validated for full-term infants). Heart rate and crying time were recorded.
Results. There were no differences in background variables between the 2 groups.
The results shows that the PIPP scores were significantly lower in the glucose group (mean: 4.6) compared with the EMLA group (mean: 5.7). The duration of crying in the first 3 minutes was significantly lower in the glucose group (median: 1 second) than in the EMLA group (median: 18 seconds). There were significantly fewer patients in the glucose group who were scored having pain (defined as PIPP score above 6); 19.3% compared with 41.7% in the EMLA group. The changes in heart rate were similar in both groups.
Conclusions. We found that glucose is effective in reducing symptoms associated with pain from venipuncture in newborns and seems to be better than the local anesthetic cream EMLA.
We thank dr Jain for his comments on our article. It is clear that pain assessment in infants is a question with many answers. There exists a big amount of pain assessment instruments using physiological and/or behavioural parameters. Due to the multidimensional nature of pain an ideal pain tool should take more than one body system into account (1). This is done by the Premature Infant Pain Profile (PIPP), that combines physiological (heart rate, oxygen saturation) and behavioural (facial expressions) variables with contextual factors like sleeping state and gestational age. This is also done by the Neonatal Infant Pain Scale (NIPS) with different behavioural parameters including face activity and body movement as well as one physiological indicator (breathing pattern).
If one wants to describe these scoring systems in terms of subjectivity and objectivity, one also have to define which of the included variables that are considered subjective. It is tempting to assume that many people would call behavioural parameters subjective (which they don’t have to be) and in that case NIPS would be more subjective than PIPP. This classification however, is not a fruitful way in choosing the ideal pain assessment tool. Both PIPP and NIPS have their place in research, and in the clinical setting.
Time since last feeding varied in both groups, but there was no difference between the groups. The number of blood collectors was limited, and all the nurses that performed the blood sampling were experienced neonatal nurses with clear instructions about the methods in the actual study.
The pain relieving effect of sucrose lasts about five minutes with the most intense effect at two minutes (2); Clinical observations reveals that the effect of glucose seems to have the same duration. Smaller doses can be given in a repeated administration if the procedure takes longer time. The international consensus document about pain in neonates (3) suggests that sweet solutions should be given as a complement to other treatment during procedures like lumbar puncture or percutaneous arterial catheter insertion.
Maria Gradin, Mats Eriksson, Jens Schollin Department of Paediatrics, Orebro University Hospital
References
1. Abu-Saad HH, Bours GJ, Stevens B, Hamers JP. Assessment of pain in the neonate. Semin Perinatol 1998;22(5):402-16. 2. Blass EM, Shah A. Pain-reducing properties of sucrose in human newborns. Chem Senses 1995;20(1):29-35. 3. Anand KJ, International Evidence-Based Group for Neonatal P. Consensus statement for the prevention and management of pain in the newborn. Archives of Pediatrics & Adolescent Medicine 2001;155(2):173-80.
Inadequate means of assessing pain in the newborn infants is unresolved clinical area. The multidimensionality of pain as explained by Gate Control Theory (1) suggests that physiological, behavioral, and modifying components of the experience should be included in any pain measure. Premature Infant Pain Profile (PIPP) can be considered multidimensional as it consists of contextual, physiological activity, and behavioral state. But most of the parameters included in PIPP are subject in nature. I think Neonatal Infant Pain Scale (NIPS) could be a better scale because it provides clinician with an objective measure of intensity of response that can be used to compare pain relief measures. What was the protocol as far as feeding was concerned? Blood collectors may inflict more painful stress depending on their experience. Did you limit the number of blood collectors? How long analgesic effect of glucose lasts? Can we use it do other short procedures like lumbar puncture or arterial puncture in the newborn infants?
References 1. Melzack R, Wall PD. Pain mechanisms: a new theory. Science 1965;150:971 -9.