Pain in the Neonate: Acknowledgement to Action

of 12

Please download to get full document.

View again

All materials on our website are shared by users. If you have any questions about copyright issues, please report us to resolve them. We are always happy to assist you.
PDF
12 pages
0 downs
2 views
Share
Description
With technological advancement and a better understanding of physiology, today there is irrefutable evidence that neonates do experience pain and even more so than their older counterparts. This pain sensitivity is further accentuated in preterm
Transcript
  R eview A rticle DOI: 10.18231/2455-6793.2017.0024  International Journal of Medical Pediatrics and Oncology, July-September, 2017:3(3):90-101 90 Pain in the Neonate Acknowledgement to Action Uma Raju 1,* , K. Venkatnarayan 2 , Arjun Raju 3 , Harshal Khade 4   1 Senior Consultant,  4 Consultant, NICE Hospital, Hyderabad, 2 Professor, Dept. of Neonatology, Command Hospital, Pune, 3 Senior Consultant, Dept. of Anaesthesia, Care Hospital, Hyderabad *Corresponding Author: Email: majgenumaraju@gmail.com Abstract With technological advancement and a better understanding of physiology, today there is irrefutable evidence that neonates do experience pain and even more so than their older counterparts. This pain sensitivity is further accentuated in preterm neonates as their pain modulating mechanism is under-developed. The hospitalized neonate is subjected to several procedures daily which result in pain of differing intensities. In the more premature neonates, even gestationally inappropriate procedures are perceived as noxious stimuli. Acute, prolonged and repetitive pain has been associated with both short and long term morbidities which result in not only delayed recovery but also neurodevelopmental and cognitive deficits in later life. As the sick and premature newborns neither verbalize nor mount vigorous behavioural responses to pain, it is often under recognized by the unpracticed healthcare provider. Several neonatal pain scales are available. However these are mostly validated for acute and not acute, repetitive or chronic pain which is the common problem faced by the sick newborns. Multidimensional pain assessment would include both physiological and behavioral parameters necessitating the use of multiple tools to complement each other. Several therapeutic options are available which include general measures which are neonatal friendly as well as non pharmacological and pharmacological measures. These used as combination therapy have been found to be more beneficial. Training of the healthcare providers so that the pain management protocol is appropriately implemented in the NICU as well as a continuous pain management quality improvement programmes with collaborative participation of all echelons would enable a more pain free and comfortable recovery of the neonates in hospital. Keywords : Neonate, Pain, Analgesia, Pain Assessment, Pain Management Introduction Pain perception is an inherent quality of life that appears early in development. (1)  The Committee on Taxonomy of the International Association for the Study of Pain defines pain as “an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage.” Further, “it is best described in terms of self reports.” (2)  Verbal communications is the gold standard for interpreting pain. However newborns cannot verbalize effectively. This leads to a problem in recognizing and acknowledging neonatal pain. Multiple lines of evidence suggest an increased sensitivity to pain in neonates when compared with older age groups. This pain sensitivity is further accentuated in preterm neonates and may not be clinically evident. Critically ill preterm neonates do not mount vigorous behavioural responses to pain and therefore require specialised and detailed assessment. (3) It has been well established that neonates especially pre-terms experience even more pain as their pain modulating adaptive mechanisms are underdeveloped and are more sensitive to noxious stimuli.   Neonates though they cannot verbalize, respond to stress and pain through specific pain behaviors as well as changes in physiologic parameters like heart rate, blood pressure and oxygen saturation. Even the most preterm neonates mount increasing responses to the pain caused by mild, moderate or highly invasive procedures and the magnitude of their response increases with their post natal age. Compared with older children, neonates exhibit greater hormonal, metabolic and cardiovascular responses to painful stimuli and may require relatively higher doses of medications for adequate pain control. The metabolism and clearance rates of most pain regulating agents in preterm neonates are slower but increase rapidly with increasing gestational age and maturity. (3) Despite this, the use of effective analgesic measures in NICUs are suboptimal. (4)   Neonates, especially the more premature ones are subjected to painful procedures at a rate of 2-15 /day in NICU. (5) The nature of pain the neonate is exposed to varies from acute pain arising from minor procedures such as heel sticks, venepuncture or lumbar puncture to chronic pain arising from conditions such as necrotizing enterocolitis and prolonged ventilation. In the extremely preterm neonate, even day to day procedures which are ‘gestationally inappropriate’ such as diaper change, daily weighing and removal of adhesive tapes is perceived as noxious stimuli which make them vulnerable to long term consequences which manifest later as abnormal long term effects. ( Error! Bookmark not defined. )  The consequences of repetitive or prolonged pain in the neonatal period include long-term changes in pain sensitivity and pain processing 6  and may be associated with a variety of neurodevelopmental, behavioral, and cognitive deficits that manifest in later childhood. (7,8)  Improved clinical and developmental outcomes highlight the importance of adequate pain control in the human neonate. (9)  Despite this evidence,  Uma Raju et al. Pain in the neonate: Acknowledgement to action  International Journal of Medical Pediatrics and Oncology, July-September, 2017:3(3):90-101 91 analgesics are used inconsistently during moderate to severely painful procedures in the newborn period. Inspite of a plethora of evidence that even the tiniest neonates experience pain, most centers do not have a pain control programme in place and even in those that do, implementation is often suboptimal.   Hence, every health care facility caring for newborns should implement an effective pain prevention programme which includes routinely assessing pain, minimizing the number of painful procedures performed, effectively using pharmacologic and non-pharmacologic therapies for the prevention of pain associated with routine minor procedures, and eliminating pain associated with surgery and other major procedures. (10) Historical Aspects Before 1980, neonatal pain was hardly recognized, evaluated or treated. (11)  In the past neonates were administered paralytic drugs without anesthesia for major surgical procedures because physicians believed that neonates were incapable of interpreting or remembering pain. Further, there was no understanding of the consequences of untreated pain. Subsequent studies and research have shown that the noxious stimuli perceived by neonates affects the neuronal growth by a complex interaction of environmental, medical risk factors and vulnerable brain regions such as hippocampus, basal ganglia and the sub plate neurons. (12,13)  [Fig. 1] These have translated in better understanding of the physiology and means of assessing the effects of pain and stress in neonates. The neonatal pain control group in its summary proceedings in 2006 defined stress as “an actual or perceived threat that leads to a disturbance of the dynamic equilibrium between an organism and its environment” and stress response as “A response  based on the individual’s perception of as control and predictability of its environment, generally characterized by changes in four primary domains: endocrine, autonomic, immunological, and  behavioral.” (14)   STRESSFUL ENVIRONMENTAL FACTORS Limited / Negative Provider Infant Interactions Loud Noise, Bright Light Medical Conditions Vulnerable Brain Regions Primary Brain Injury Chronic Lung Disease Apnoea and Bradycardia Severe Hemorrhagic/ Hypothyroxinemia Ischemic white matter injury Essential Fatty Acid Deficiency Hyperbilirubinemia Interventions - Procedures Drugs eg Glucocorticoids Fig. 1: Interaction of factors potentially affecting the vulnerable regions of Brain (13)   Physiology of Pain in Neonates   The anatomic pathways of the peripheral nervous system appear to be functional by 20 weeks post-conception, although tracts in the spinal cord and brainstem may be variably myelinated, and the areas of pain processing are different from that in the mature central nervous system (CNS). The number and types of peripheral nociceptors is similar to adult numbers by 20 to 24 weeks’ gestation in the human fetus, implying a greater density per area of skin. These are connected via peripheral nerve fibers, which consist of the A, delta and C fibers with the developing spinal cord dorsal horn at that time. During development, the thickly myelinated A beta fibers, which transmit light touch and proprioception in the adult, also appear to transmit noxious information to pain processing areas of the spinal cord. Lack of myelination in the A, delta or C fibers or spinal cord tracts was proposed as an argument against pain perception in neonates. But even in adults, most pain impulses are carried, albeit slowly, via unmyelinated C fibers. Thus, incomplete myelination merely implies a slower conduction rate. Numerous receptor molecules in the membranes of these nociceptors in neonates affect the nerve impulse that is ultimately transmitted to the CNS very early in gestation. These fibers differ from each other in their   Subplate Neurons Basal Ganglia Thalamus Hippocampus  Uma Raju et al. Pain in the neonate: Acknowledgement to action  International Journal of Medical Pediatrics and Oncology, July-September, 2017:3(3):90-101 92 response to different types of tissue injury and in their thresholds and other physiologic properties. Thus, the CNS of the developing fetus receives a repertoire of different information, depending on the type and intensity of the noxious stimulation. The biochemical mediators involved include chemicals like bradykinin, calcium, potassium, substance P, and prostaglandins which activate the nociceptors of the A delta and C afferent fibers. This activation leads to the pain impulse and subsequently stimulates local wheal and inflammatory response. More importantly, it also results in local dendritic sprouting of nerves and a state of hyperalgesia, which results in lasting experience of pain till adulthood. By 22 to 24 weeks’ gestation, ascending pathways seem to connect with the supraspinal centers in the thalamus, subplate zone, and sensory cortex. However, because of weak linkages between the afferent fibers and dorsal horn of the spinal cord, the effects of pain last longer. In addition, due to over expression of NMDA receptors in the spinal cord, there is hyper-stimulation of dorsal horn interneurons, enroute the transmission to cortical centers, besides the mediation by substance P. This results in increased excitability of uninvolved areas, called ‘wind up’ phenomenon. Because of this wind up phenomenon, preterms experience a more robust, longer pain response, have a lower threshold and feel painful response from uninvolved tissues. In addition to these physiological peculiarities, the preterm neonate is unable to modulate pain as a term neonate or an adult, due to lack of modulation of pain response and due to paucity of levels of expression of dopamine, serotonin, and norepinephrine in the preterm spinal cord. By 20 to 22 weeks’ gestation, autonomic responses from painful stimuli lead to increases in heart and respiratory rate, implying functionality at that time. By 25 to 26 weeks’, the same facial expressions from pain that are seen in adults, such as the brow bulge, eye squeeze, and nasolabial furrow, is evident in preterm infants. These expressions and the autonomic responses provide proof that pain is part of life in the NICU, and although neonates cannot verbalize pain, these expressions and responses allow assessment of pain in term and preterm neonates. These expressions have been used in assessing painful responses in the preterm neonate. (Fig. 2) Fig. 2: Facial Expressions of Preterm Neonate in the PIPP Scoring System (1) Assessment of pain and stress in neonates Accurate pain assessment is the key and central issue that confronts clinicians at the bedside of preterm neonates. Although many validated methods for pain assessment are available, none of them are widely accepted or clearly superior to others. (15)  The quality of the pain evaluation depends on the knowledge, ability, and willingness of the observer to analyze and judge nonverbal behaviors of a phenomenon as subjective as pain. In this context, validated pain evaluation tools should be used to minimize the different perceptions of neonatal pain among the health professionals, making decisions regarding the need or the intensity of analgesia as objective as possible.  Uma Raju et al. Pain in the neonate: Acknowledgement to action  International Journal of Medical Pediatrics and Oncology, July-September, 2017:3(3):90-101 93 Although several neonatal pain scales are available in the literature, most are validated for acute neonatal pain. Very few are designed to evaluate repetitive acute pain or non-acute pain status, which are the most common and difficult situations when dealing with critically ill newborns. Ideally, the multidimensional pain assessment should include physiologic and behavioral indicators of pain. In the face of the absence of a gold-standard pain measurement tool, the clinical team should use multiple tools that may complete and confirm each other. The Premature Infant Pain Profile (PIPP) is designed to assess pain during and soon after acute invasive procedures and includes incorporation of physiological parameters such as heart rate, oxygen saturation and the behavioural state as per gestational maturation. (16)  The PIPP score is the best validated score for neonatal acute pain. Table 1: The Premature Infant Pain Profile(PIPP) (16) Process Indicator 0 1 2 3 Chart GA ≥36wks  32-35 6/7  28-31 6/7   ≤ 28 wks   Score 15 sec before event Behavioral state Active awake Eyes-open Facial move + Quite awake Eyes- open No facial movements Active sleep Eyes-closed Facial movements + Quite/sleep Eyes closed No facial movements Heart rate Baseline: Maximum HR 0-4/min increase 5-14/min 15-24/min ≥ 25/min  O2 Saturation Baseline: Minimum O2 saturation 0- 2∙4% fall   2∙5 - 4∙9% fall  5- 7∙4% fall   ≥ 7∙5% fall  Observe for 30 sec after the event Brow Bulge None (0-9%)   Min (10-39%) Moderate (40-69%)   Maximum (≥ 70% of time)  Eye Squeeze Nasolabial furrow    Score the corrected gestational age, Assess base line HR, SPO2 before procedure    Score behavioral state 15 sec before the event, Observe infant for 30 sec after the event    The min score=0, max score-21; higher the score greater the pain    To be done by staff nurse/ resident doctor and record in the file The Neonatal Infant Pain Scale (NIPS) is relatively simple and has been recommended as the fifth vital sign for newborns who require intensive care. This pain scale can be used by the nursing staff as often as required and includes easily assessable features such as facial expression, type of cry, breathing pattern and states of arousal and posture of arms and legs. The major drawback of the score is that very sick newborns may falsely have low scores. (17) Echelle Douleur Inconfort Nouveau-Ne´ (EDIN) coding system assess chronic pain and to apply this neonatal pain and discomfort scale, nurses observe the infant for several hours during and between caring and feeding and test the efficacy of consoling. EDIN scores greater than 6 indicate pain.   The scoring system is based on facial activity, type of body movements, quality of sleep, quality of contact with nursing staff and consolability. (18)  The other assessment tools include unidimensional behavioural scales of Neonatal Facial Coding system (NCFS) (19)  or behavioural Indicators of Infant pain (BIIP). (20)  These scoring systems at most help the care givers in sensitizing to neonatal pain communications. The CRIES Score assesses crying, requirement for increased oxygen administration, increased vital signs, expression, and sleeplessness in both preterm and term infants and, because of its ease of administration, it is used widely by primary care practitioners. (12) However, no “gold standard”  can be recommended for broad adoption in clinical practice because of 2 problems that are common to all assessment methods. This is because:- 1.   These methods were developed from studies of neonates who underwent acute painful procedures (heel stick, venipuncture, circumcision). Physiologic or behavioral parameters chosen for inclusion in these methods were specifically those that changed most acutely in response to tissue injury and subsided after painful stimulation was over. Subsequent research, however, noted preterm newborns who were more immature, asleep, or exposed to previous painful procedures were less likely to demonstrate specific responses to pain, whereas previous physical handling accentuated their responses to acute pain. (21-22) 2.   Significant inter-observer variability occurs and can be reduced but not eliminated by training or greater experience. (23) The observer variables include many complex characteristics such as age, sex, ethnicity, religion, marital status, personal experience, educational status, professional expertise and socio economic status. The patient variables include gestational age, sex, past experience, physical state of wakefulness, degree of invasiveness of procedure. (24,25)  3.   The limitations of assessments are further increased in case of sick neonates such as those on  Uma Raju et al. Pain in the neonate: Acknowledgement to action  International Journal of Medical Pediatrics and Oncology, July-September, 2017:3(3):90-101 94 ventilator. In the setting of NEOPAIN trial, the markers found useful to assess persistent pain in neonates in ventilated babies receiving placebo in contrast to those receiving morphine were: facial expressions of pain, high activity levels, poor response to routine care, and poor ventilator synchrony. (26) Management and Prevention of Pain Prevention and management of pain involves a multipronged strategy. It entails creating an environment using general measures conducive to neonatal care, training healthcare workers to recognize pain in the neonate, pharmacological and non-pharmacological measures. A.   General Measures: The most obvious strategy would be to reduce the unnecessary painful and stressful conditions in the NICU. Such an approach would include reducing the number of bedside disruptions in care. Other strategies might include bundling interventions, eliminating unnecessary laboratory or radiographic procedures, using transcutaneous measurements when possible, and minimizing the number of repeat procedures performed after failed attempts. (26,27)  Table 2 lists suggested general measures that can be adopted in neonatal care units. Table 2: General measures to reduce pain S. No. Measures 1. Avoid bright light   2. Limit numbers of painful procedures and unnecessary handling   3. Clustering nursing interventions   4. Swaddling and facilitated tucking   5. Judicious use of Investigations   6. Bundling investigations   B.   Non Pharmacological Measures: A variety of non-pharmacologic pain-prevention and relief techniques have been shown to effectively reduce pain from minor procedures in neonates.[Table 3] These include use of oral sucrose/glucose (28-31)  breastfeeding, (32)  nonnutritive sucking, (33)   “kangaroo care” (skin -to-skin contact), (35)  alternative female kangaroo care, (36)  facilitated tuck (holding the arms and legs in a flexed position), swaddling, (38)  and developmental care, which includes limiting environmental stimuli, lateral positioning, the use of supportive bedding, and attention to behavioral clues. (39)  These measures have been shown to be useful in preterm and term neonates in reducing pain from a heel stick, venipuncture and subcutaneous injections and are generally more effective when used in combination than when used alone. (38,40) Oral Sucrose Administration Sucrose administration is the most widely studied non-pharmacologic intervention for infant pain management. The soothing, calming, and pain-relieving effects of sucrose during painful procedures in neonates are believed to be mediated by the release of endogenous opioid neurotransmitters such as beta-endorphins. Oral sucrose used alone is appropriate only for pain of very short duration (2 to 3 min), such as heel stick puncture and venipuncture. For treatment of moderate-to-severe pain or when pain is expected to last longer than a few minutes, it should be used in combination with other analgesics or local anesthetics. Table 3: Non-pharmacological Measures S. No. Measures 1 Sucrose/ Glucose solution   2 Breast feeding/ breast milk supplementation   3 Skin to skin care   4 Swaddling/ Facilitated tucking   5 Tactile stimulation like stroking, caressing, massaging   6 Distraction measures like talking, music, crooning   7 Non nutritive sucking using pacifiers      These measures in combination are more effective than when used in isolation. Oral sucrose can be administered with a syringe or through a pacifier. Sucrose concentrations of 24% to 50% are recommended as lower concentrations have been found to be less effective. Volumes of 0.1 mL of oral sucrose solution are given to preterm infants of 24 weeks’ gestational age and up to 2 mL to term infants. The dose must be administered 2 to 3 minutes before
Related Search
We Need Your Support
Thank you for visiting our website and your interest in our free products and services. We are nonprofit website to share and download documents. To the running of this website, we need your help to support us.

Thanks to everyone for your continued support.

No, Thanks