Heel blood sampling in preterm infants: which technique?

AARC Clinical Practice Guidelines: Capillary Blood Gas Sampling for Neonatal and Pediatric Patients

In the absence of an indwelling arterial catheter, capillary blood gas sampling may be used to evaluate the acid/base and ventilation status of neonatal and pediatric patients with cardiorespiratory conditions. These guidelines were developed from a comprehensive review of the literature to provide guidance for the collection, handling, and interpretation of blood obtained from an arterialized capillary sample. Capillary and venous blood gas measurements are a useful alternative to arterial blood gas measurements for neonatal and pediatric patients who do not require close monitoring of [Formula: see text] In the presence of alterations in body temperature, blood pressure, or peripheral perfusion, agreement between a capillary blood gas with an arterial sample is recommended to determine whether changes in these physiologic conditions reduce reliability. Perfusion to the sample site should be assessed and preference given to blood sampling from a well perfused site, and blood should be analyzed within 15 min of sampling to minimize the propensity for pre-analytical errors. Clinicians should consider re-collecting a blood sample, obtained from an artery, vein, or capillary, when the blood gas or analyte result interpretation does not align with the patient's clinical presentation. A pneumatic tube system can be reliably used to transport blood gas samples collected in a syringe and capillary tube to a clinical laboratory for analysis. To reduce the cumulative pain effect and risk of complications, the capillary puncture procedure should be minimized when possible. Non-pharmacologic interventions should be used to reduce pain associated with capillary blood gas sampling. Automatic lancets are preferred to puncture the skin for capillary blood gas collection.

Neonatal pain response to automatic lancet versus needle heel-prick blood sampling: A prospective randomized controlled clinical trial

BACKGROUND

Automatic lancets have been reported to be superior to manual lancets in terms of pain and treatment time. However, no studies have yet been published comparing automatic lancet and needle puncture heel-prick blood sampling. The objective of this study was to compare the pain response and efficiency between the automatic lancet and needle at the time of heel blood sampling. The design was a randomized controlled trial. The inclusion criteria for the participants were a birthweight of ≧1,500 g and a gestational age of ≧30 weeks.

METHODS

The study examined a total of 105 neonates who were randomized into an automatic lancet group (n = 53) and a needle group (n = 52). The parameters measured included blood collection time, number of calf squeezes, duration of audible crying, and the Neonatal Infant Pain Scale (NIPS) score. The main outcome measure was audible crying duration.

RESULTS

The duration of audible crying was significantly shorter in the automatic lancet group when compared to the needle group (median 3 s, interquartile range (IQR) 0-33 s vs median 39 s, IQR 5-91.5 s, P = 0.0023). The NIPS score at the time of puncture was significantly lower in the automatic lancet group than in the needle group (median 1, IQR 0-5 vs median 5, IQR 3-6, P = 0.0060). There was no significant difference in the blood collection time and the number of calf squeezes between the two groups. The automatic lancet was found to be less painful than the needle puncture in neonatal heel-prick blood sampling with no significant difference in blood sampling time.

CONCLUSION

The automatic lancet was found to be less painful than the needle puncture in neonatal heel-prick blood sampling with no significant difference in blood sampling time.

Assessing Neonatal Pain, Duration of Crying and Procedure Time following Use of Automatic or Manual Heel Lances: A Randomized Controlled Study

OBJECTIVE

The objective of this study was to compare neonatal pain, duration of crying and procedure time following use of automatic or manual heel lancets.

METHODS

This randomized trial was conducted with neonates undergoing heel prick procedures in a neonatal intensive care unit for routine blood bilirubin monitoring. An information form, an observation form and the Neonatal Infant Pain Scale (NIPS) were used. Pain before, during and after (1 and 3 min) was assessed using NIPS scoring.

RESULTS

Seventy neonates were included (automatic lancet, n = 35; manual lancet, n = 35); there was no difference between the groups (p > 0.01). Pain scores were significantly lower, with automatic lancets compared with manual lancets (p = 0.001). The duration of crying after the procedure (p = 0.001) and procedure time (p = 0.001) was significantly shorter with automatic lancets compared with manual lancets.

CONCLUSION

Automatic heel lancets in neonates are more effective than manual lancets at reducing pain, and shorten the procedure time and duration of post-procedural crying.

Iatrogenic skin injury in the neonatal intensive care unit

Although neonatal care has become more and more meticulous with significant changes in technology in the neonatal intensive care unit (NICU) in the past 50 years, iatrogenic cutaneous injuries continue to occur. Although the incidence of severe injuries is decreasing because the more difficult procedures are being replaced by improved techniques, skin injuries have not yet been completely eliminated. However, the nature and causes of cutaneous injuries have changed, and the injuries are frequent but generally minor. The major risk factors are low birth weight, gestational age, length of stay, a central venous line, mechanical ventilation, and support with continuous positive airway pressure. The rate of iatrogenic events is about 57% at gestational ages of 24-27 weeks, compared with 3% at term. There are no current comprehensive reviews of iatrogenic cutaneous injury. The purpose of this review is to describe the iatrogenic cutaneous injuries that may occur in the newborns as a consequence of perinatal and postnatal medical procedures. With increased survival of extremely-low-birth-weight (ELBW) infants and changing modes of management in the NICU, neonatologists must make every effort to recognize injuries and prevent their occurrence in the NICU.

Non-pharmacological pain relief

The delivery of humane neonatal care demands that attention is given to interventions that reduce pain effectively. Painful procedures are common for neonatal patients and a growing body of research suggests that simple non-pharmacological methods are effective in reducing the signs of pain. Both oral sucrose and pacifiers reduce pain scores during procedures, and other simple measures, including facilitated tucking and skin-to-skin contact, might also be effective. Organising care to reduce exposure to painful procedures and also optimising the devices used for procedures might reduce the experience of pain. There is some evidence of long-term improvement in pain sensitivity following pain reduction programmes. Further research is needed to understand the detail of how and when to best apply these interventions; the long-term outcomes of policies that give routine prominence to pain reduction on the neonatal intensive care unit also need to be investigated. The absence of long-term effect should not impede the introduction of these simple, low-cost humane measures.

Topical amethocaine gel for pain relief of heel prick blood sampling: a randomised double blind controlled trial

BACKGROUND

Heel prick blood sampling is a commonly performed and painful procedure in the newborn infant. Use of a topical local anaesthetic does not relieve this pain. A 4% w/w amethocaine gel (Ametop) reduces the pain of venepuncture in the newborn but has not been tried with heel pricks.

AIM

To investigate the effect of topical amethocaine gel on the pain of heel prick in the newborn infant.

DESIGN

Randomised, double blind, placebo controlled trial.

SUBJECTS

Sixty newborn infants, gestation 28-42 weeks (median 36), postnatal age 1-16 days (median 5) undergoing routine heel prick blood sampling.

METHODS

A 1.5 g portion of 4% w/w amethocaine gel or placebo was applied to the skin under occlusion for one hour, then wiped away. Heel prick blood sampling with a spring loaded lance was performed five minutes later. The procedure was videotaped and pain assessed at one second intervals using an adaptation of the neonatal facial coding system (NFCS). No or minimal pain was defined as a cumulative score of less than 5 (out of 15) in the three seconds after firing of the lance and as lack of a cry in the first five seconds.

RESULTS

In terms of a low NFCS core and lack of cry (p = 0.12) 20 of 30 (67%) in the amethocaine group and 13 of 29 (45%) in the placebo group had no or minimal pain in response to the heel prick. The median cumulative NFCS score over the three seconds after firing the lance was 3 (interquartile range 0-6) in the amethocaine group compared with 5 (interquartile range 1-10) in the placebo group (p = 0.07). These differences are not significant.

CONCLUSIONS

Topical amethocaine gel does not have a clinically important effect on the pain of heel prick blood sampling and its use for this purpose cannot therefore be recommended. Alternative approaches to the relief of pain from this procedure should be explored.

Treatment of pain in the neonatal intensive care unit

Pain is a disruptive influence on infants in the NICU. The most obvious and effective strategy to decrease infant pain in the NICU is to stringently limit the frequency of painful procedures, especially those that are most commonly reported (i.e., heel lances and endotracheal suctioning), and have these performed on infants that are most unstable or critically ill by the most experienced person available. Organizational concerns over the cost of NICU care have forced a re-evaluation of the necessity of certain diagnostic and care procedures and a limiting of procedures to those that can be documented to positively affect clinical outcome. Pharmacologic and nonpharmacologic strategies are essential to the prevention and management of neonatal pain, and these should be considered for complementary use for every infant. Research has shown the safety and effectiveness of some of the strategies in reducing mild pain caused by brief invasive procedures; however, many of the studies had methodologic limitations. Therefore, more research is required to determine the comparative efficacy of the various strategies and to document additive or synergistic effects when combined.

Ultrasound study of heel to calcaneum depth in neonates

AIM

To investigate whether it would be safe to extend the currently recommended area of sampling to the whole heel in neonates.

METHODS

Eighty newborn infants were studied, weight range 0.56 to 4.34 kg, gestation 24 to 42 weeks. Ultrasound scanning was used to measure the shortest distance between the skin and the perichondrium of the calcaneum.

RESULTS

The shortest depth of perichondrium was in the centre of the heel and ranged from 3 to 8 mm. In 78 of the 80 infants the distance was 4 mm or more. There was a small but significant positive correlation with weight.

CONCLUSIONS

Standard automated lancets for preterm use that puncture to a depth of 2.4 mm may be safely used anywhere over the plantar surface of the heel. The posterior aspect of the heel should be avoided. Reducing the density of heel pricks should reduce the associated pain.

Environmental and behavioral strategies to prevent and manage neonatal pain

This article provides an overview of environmental and behavioral methods for pain management in newborn infants. Specific interventions in the areas of containing, positioning, nonpainful sensory stimuli, non-nutritive sucking, sucrose, and procedural technique are discussed. The conceptual framework and research evidence for the efficacy of these methods are examined. Opportunities for further research to evaluate the comparative efficacy of environmental and behavioral pain interventions are emphasized.

Practical approach to analgesia and sedation in the neonatal intensive care unit

The anatomic and physiological bases for nociception are present even in very preterm neonates. Neonates show the same behavioral, endocrine, and metabolic responses to noxious stimuli as older subjects. Preterm infants appear to be more sensitive to painful stimuli and have heightened responses to successive stimuli. Infants receiving intensive care are subjected to frequent stressful procedures and also chronic noxious influences related to the environment of care. Inflammatory conditions such as necrotizing enterocolitis may also cause pain. Untreated pain in babies is associated with increased major morbidity and mortality. Nonpharmacological interventions, including environmental modification and comforting during procedures reduce stress. Intravenous opiates are the mainstay of pharmacological analgesia. A pure sedative agent can provide physiological stability in settings in which there are less acutely painful stimuli or when there are adverse effects from, or tolerance to, opiates. Local anesthesia of skin and mucous membranes is helpful for invasive procedures. Antipyretic analgesics such as acetaminophen have a role in inflammatory pain.

Does change in skin perfusion provide a good index to monitor the sympathetic response to a noxious stimulus in preterm newborns?

Skin perfusion was measured using laser Doppler fluximetry (LDF) in 16 preterm babies undergoing a standardised heel prick procedure. Although there was a significant reduction in skin blood flow following the heel prick, this was variable and dependent on basal skin blood flow. This, together with loss of data due to movement artefact, makes this technique unreliable in quantifying the sympathetic response to a noxious stimulus in preterm infants.

Exposure to invasive procedures in neonatal intensive care unit admissions

The nature and numbers of invasive procedures were studied in 54 consecutive infants admitted to a neonatal intensive care unit. Over 3000 procedures were recorded, 74% in infants below 31 weeks of gestation. One infant (23 weeks' gestation, birth weight 560 g) underwent 488 procedures. Heel prick blood sampling was the most common procedure (56%), followed by endotracheal suction (26%) and intravenous cannula insertion (8%). Invasive procedures which would cause pain or distress to a child are frequently performed on infants admitted to the neonatal intensive care unit. A reduction in the number of procedures, modifying them, or providing adequate analgesia could relieve some of this pain and distress.