Pain and its effects in the human neonate and fetus

Comparison of continuous infusion of fentanyl to bolus dosing in neonates after surgery

OBJECTIVE

Concern about respiratory depression may lead to underuse of postoperative narcotic analgesia in neonates. The authors compared continuous infusion of fentanyl with bolus dosing in infants after surgery to determine whether continuous infusion is associated with less respiratory depression.

STUDY DESIGN

In the first phase of the study, 16 patients were randomly assigned to receive fentanyl by continuous infusion (C) or bolus dosing every 2 hours (B) in a double-blinded trial. Respiratory events were recorded. An observational pain score and saliva for cortisol concentration were obtained 2, 8, and 24 hours after beginning treatment to compare efficacy of pain control. In the second phase, 20 additional patients received fentanyl by continuous infusion in an unblinded fashion, with the same data collection, to more accurately determine the incidence of respiratory events.

RESULTS

In phase 1, apnea occurred in eight of nine B patients (89%) compared with one of seven C patients (14%; P < .009), prompting termination of the randomized trial. The incidence of apnea or significant respiratory depression in the next 20 patients (phase 2) who received fentanyl by continuous infusion was 25% (5 of 20; P < .01 v B). Episodes of apnea in B patients required significantly more intervention than episodes in C patients (P < .01). However, in phase 2, more patients remained intubated and ventilated than in phase 1. Pain scores and salivary cortisol concentrations decreased over the 24-hour study period and were similar in B and C patients during both phases of the study.

CONCLUSION

Continuous infusion of fentanyl at the doses studied is associated with pain control similar to that with bolus dosing at regular intervals. Although episodes of respiratory depression were less severe and less frequent for C patients, there may be an increased need for ventilator support with continuous infusion of fentanyl to achieve acceptable pain control. Providing adequate pain control to neonates in the immediate postoperative period remains a challenge.

Treatment of pain in pediatric oncology: a Swedish nationwide survey

Pain treatment is a crucial aspect in the care of children with cancer and there are many studies demonstrating inefficient pain treatment. In this study, questionnaires dealing with pain treatment of children with malignant diseases were sent to all (47) pediatric departments in Sweden. The aims of this nationwide survey were to evaluate the extent and causes of pain, the use of methods for pain evaluation (e.g. analysis of type of pain and monitoring of pain intensity), principles of pain management, side effects of pain treatment and the educational needs of physicians and nurses regarding these issues. The response rate was 100%. Answers from physicians and nurses reveal that pain is a common symptom during different periods of cancer treatment. Pain due to treatment and procedures is a greater problem than pain due to the malignant disease itself. Instruments for the measurement of pain intensity and analysis of the type of pain are still rarely used. Most physicians (63%) follow the analgesic 'ladder' principle recommended by World Health Organization (WHO). According to a majority of physicians and nurses (72%), pain could be treated more effectively than it is presently, and 64% state that they need more time for the management of pain. Both physicians and nurses state that they need additional education in different areas of pain evaluation and pain treatment. Swedish treatment practices for the management of pediatric cancer pain roughly follow the published guidelines, but many improvements are still necessary.

Anesthetic efficacy of eutectic prilocaine-lidocaine cream in pediatric oncology patients undergoing lumbar puncture

OBJECTIVE

To evaluate the efficacy of eutectic mixture of local anesthetics 5% (Emla) in reducing pain associated with lumbar punctures in children.

DESIGN

Prospective, double-blind, randomized, placebo-controlled trial.

SETTING

University pediatric hospital.

PATIENTS

Eleven pediatric oncology patients (mean age 6.6 y, range 4-16) who underwent 31 lumbar punctures.

MAIN OUTCOME MEASURES

The analgesic effect was measured by using two methods. The first was a 10-point visual analog scale reported by the patient and the second was an 8-point behavioral pain scale assessed by the nurse who applied the cream.

RESULTS

Emla cream was associated with significantly lower pain scores than those with placebo as measured by the patient when the puncture was successful on the first attempt (2.0 +/- 1.6 Emla group, 3.8 +/- 1.9 placebo group; p < 0.05).

CONCLUSIONS

The use of Emla cream may reduce pain substantially only in patients who undergo a successful lumbar puncture on the first attempt.

[Evaluation of the views of 189 mothers on the sensory capacities of their newborn infants. Can the information be a tool for prevention?]

IS INFORMATION A TOOL FOR PREVENTIVE ACTION? The aim of this study was to evaluate maternal beliefs concerning neonatal performances, to compare them with currently accepted knowledge and to analyse parameters that could influence the maternal judgement.

POPULATION AND METHODS

A total of 189 mothers in the postpartum period were prospectively questioned about their beliefs concerning the developmental visual, auditive, olfactive, gustative and sensitive functions of their neonates.

RESULTS

Only 57.7% of mothers agreed with the fact that their neonates were able to see. Similarly, there were more than 80% for the olfactive and gustative function and more than 90% for the auditive function and pain discrimination. Multiparity and high level of professional activities improved the mothers' answers about the visual abilities of their neonates. Scientific information through media appeared poorly assimilated.

CONCLUSIONS

The time spent by the mothers in the maternity home or word could be used to inform them.

CAUDAL ANALGESIA FOR POSTOPERATIVE PAIN RELIEF IN CHILDREN

Postoperative pain relief in 40 children undergoing elective infraumbilical surgery was assessed after caudal epidural adminstration of either lignocaine or bupivacaine in the doses of 0.5 mL/kg body weight of a 1 per cent solution and 0.5 mL/kg body weight of a 0.25 per cent solution respectively. Pain free period was assessed by subjective pain scales. The pain free period was significantly prolonged in children who were given bupivacaine (14.75 ± 2.75 hours) as compared to lignocaine (7.25 ± 3.25 hours).

[Anatomical route of pain in premature newborn infants]

Recent research about nociceptive pathways in newborn infants have shown that, even very immature, preterm infants have all the anatomical and functional components required for the perception of painful stimuli. However, the perception of pain in preterm infants is thought to be slightly different from that of term infants: because of a lack of myelination of their sensitive fibers and a still immature cortical organization of the somatosensory system, painful stimuli are perceived more widespread and durable. In addition, the threshold of pain seems to be lower in premature infants, probably due to a lack of protection of their spinal and supraspinal inhibitory pathways. Finally, abnormal behavioural imprinting secondary to early painful stimuli is now suggested. Thus in contrast with the former misconception of "insensitivity towards pain", premature infants must be now considered as "hypersensitive" and vulnerable.

Stress responses in preterm neonates after normal and at-risk pregnancies

OBJECTIVE

To evaluate the autonomic response in preterm neonates born after an at-risk pregnancy.

METHODOLOGY

Twenty-one preterm neonates (gestational age; GA) 29-37 weeks; bodyweight (BW): 720-2113 g; postnatal age: 2-126 days), born after at-risk pregnancies (stressed (STR) group), were compared to 30 preterm neonates (GA: 26-36 weeks; BW: 813-2380 g: postnatal age: 2-86 days) without any intrauterine risk factor (C group). A 10 s pain stimulus was given on the forefoot and heart rate, respiratory rate and blood pressure were measured at 15 and 30 s, at 1, 2, 3, 4 and 5 min. After 10 s ocular compression six cardiac variables were recorded.

RESULTS

After the pain stimulus the STR-group had a significant increase of heart rate at 15 s and an increase of diastolic blood pressure at 30 s. In the C group a significant increase of heart rate at 15 s was recorded. For the respiratory rate both groups showed an initial depression (significant at 15 s in the C group) followed by an increase. The time to react to the ocular compression was significantly shorter in the STR-group than in the C-group and thus more parasympathetic.

CONCLUSIONS

We hypothesize that the different sympathetic and parasympathetic reaction patterns of the vital parameters to triggers in the STR-group are due to chronic stress, pointing to an altered maturation of the two components of the autonomic nervous system after chronic intrauterine stress (CIUSTR).

Routine use of fentanyl infusions for pain and stress reduction in infants with respiratory distress syndrome

OBJECTIVE

To determine whether fentanyl infusions given to premature infants with respiratory distress syndrome reduce stress and improve long- and short-term outcome.

METHODS

Twenty premature infants undergoing mechanical ventilation for respiratory distress syndrome were randomly assigned, in a double-blind fashion, to receive fentanyl by continuous infusion or a volume-matched placebo infusion. A behavioral state score was used to assess the infants' behavior. Cortisol and 11-deoxycortisol levels were measured as physiologic markers of stress. Urinary 3-methyl histidine/creatinine molar ratio was determined and the fractional excretion of urea was measured to assess catabolic state. Ventilatory indexes were recorded for each infant.

RESULTS

Infants receiving fentanyl showed significantly lower behavioral state scores (p < 0.04) and lower heart rates (p < 0.001) than those receiving placebo. 11-Deoxycortisol levels were lower in the fentanyl group on days 3, 4, and 5 of the study (p < 0.003). 3-Methyl histidine/creatinine ratios and fractional excretion of urea were not significantly different between the two groups. On the third day of the study, infants receiving fentanyl required a higher ventilator rate (p < 0.01), higher peak inspiratory pressures (p < 0.001), and higher positive end-expiratory pressure (p < 0.0001) than those receiving placebo. There was no difference in long-term outcome with respect to the incidence of bronchopulmonary dysplasia, intraventricular hemorrhage, or sepsis or with respect to the duration of ventilator use.

CONCLUSIONS

Although there was a reduction in stress markers in the infants receiving fentanyl, we were unable to demonstrate an improvement in catabolic state or long-term outcome. In addition, the infants receiving fentanyl required higher ventilatory support in the early phase of respiratory distress syndrome than did those receiving placebo.

Nonpharmacological interventions to use with children in pain

Children's pain is often poorly managed, and interventions other than medications are rarely used. Yet many nonpharmacological interventions are helpful in managing children's pain. These techniques are reviewed, and the physiological mechanisms underlying them are briefly addressed. A discussion of the three major classifications (sensory, cognitive, and cognitive-behavioral) of interventions follows. Factors that influence the use of nonpharmacological techniques, including type of pain and developmental level, are discussed.

Oral sweet solution reduces pain-related behaviour in preterm infants

To evaluate the effectiveness of oral sucrose in the prevention of pain-induced crying in preterm infants, a sample of 28 healthy neonates (15M, 13F; gestational age at procedure less than 37 weeks) who were having routine blood drawn by arm venipuncture was studied. Infants were randomly allocated to receive by mouth, using a syringe, 2 ml of one of three solutions: spring water (group W) and sucrose 12 and 24% w/v (groups S12 and S24, respectively), all in water vehicle. After 2 min, while awake, arm venipuncture was performed and duration of crying was measured. The time spent crying was reduced in the group treated with the sweetest solution (S24, n = 8, mean = 19.1 s). No difference was observed between the S12 group (n = 8, mean = 63.1 s) and W group (n = 12, mean = 72.9 s). Physiological measurements were recorded at different time points to evaluate excessive basal and procedural distress.

Pain responses of hospitalized infants and children to venipuncture and intravenous cannulation

The purpose of this study was to describe the experience of pain in infants and children in response to venipuncture and intravenous cannulation. Data on physiological, behavioral, and subjective responses were collected from 90 infants and children, in subgroups of 1 to 12 months, 1 to 3 years, 4 to 6 years, and 7 to 12 years. Changes in behavior were significant in all four groups, although the toddler group was the only group that showed a significant physiological change. The subjective measures showed that the children were able to identify their pain sites and intensity.

[Severe head injuries in neonates and infants: physiopathological and therapeutic aspects]

Severe head injuries in infants have specific circumstances such as obstetrical injury, battered infant, shaken infant. Pediatric scales must be used for neurological evaluation, the Bicêtre scale being a sensitive index of clinical course. Transfontanellar ultrasound can be useful as first line tool of evaluation of brain injury, but computerized tomography scan is necessary to correctly assess the brain lesions and the presence of hematoma. Hemorragic lesions can rapidly lead to hypovolemic state which must be prevented, or treated without delay. Treatment requires hemodynamics and hydroelectrolytic support, measures to control intracranial hypertension, sedation, and neurosurgical intervention according to the hemorragic lesions.

Evidence for morphine downregulating immunocytes during cardiopulmonary bypass in a porcine model

Cardiopulmonary bypass is associated with both cellular immunosuppression and an inflammatory response. Previous studies have demonstrated that morphine, a naturally occurring substance, can downregulate granulocyte, monocyte and endothelial activity. It can even prevent the activation caused by exposing these cells to plasma obtained from patients undergoing cardiopulmonary bypass. The present study demonstrates that preadministering a high dose of morphine (3.3 mg/kg) to pigs prior to cardiopulmonary bypass also diminishes the activation levels of these cells. In animals not given morphine, monocyte activation levels were 45% compared to 14% exposed to the opiate. Granulocytes also exhibited the same statistically significant (P < 0.05) drop in cellular activation. Activation is determined by computer-assisted microscopic image analysis whereby cellular shape is indicative of the cells activity. Additionally, in animals pretreated with morphine, a twofold increase in the number of cells was obtained, indicating that the endothelium also was downregulated.

Reduction of pain response in premature infants using intraoral sucrose

The potential of sucrose to reduce the pain response in a group of healthy premature infants was investigated. Fifteen infants of 32-34 weeks postmenstrual age were tested in a blind crossover manner on two separate occasions no more than two days apart. Either 1 ml of 25% sucrose solution or sterile water was syringed into the baby's mouth 2 minutes before routine heel lancing. Response to the painful stimuli was measured by duration of cry and by facial expression (pain score). There was a significant reduction in the duration of first cry, the percentage of time spent crying in the 5 minutes after heel prick, and the pain score in the sucrose treated group. It is concluded that sucrose has analgesic effects in healthy premature infants.

Effect of non-sucrose sweet tasting solution on neonatal heel prick responses

A substance commercially described as 'sugar free,' used as a sweetener for paracetamol suspension, was evaluated on measures of neonatal pain. Sixty infants were randomly allocated to receive one of four solutions before heel stab blood sampling: sterile water (placebo); 25 or 50% sucrose (weight/volume); and the commercial sweet-tasting solution. There was a significant reduction in crying time and pain score 3 minutes after the painful stimulus in all groups compared with the controls. It is concluded that this sweet-tasting solution has analgesic effects as potent as those of concentrated sucrose solutions.

Effects of fentanyl administration on general and cerebral haemodynamics in sick newborn infants

Despite the wide use of fentanyl for analgesia in newborns, concerns have been raised about potential haemodynamic side-effects. Since sick newborns may lose their cerebral blood flow autoregulation, a drug-induced haemodynamic instability could lead to brain injury. We assessed the effects of a 15-min infusion of fentanyl (3 micrograms/kg) on the general and cerebral haemodynamics in 15 newborns (median gestational age 29 weeks, 25th-75th percentile, range 28-31 weeks; birthweight 1170 g, range 955-1790 g). The heart rate and mean arterial blood pressure were continuously recorded. Mean cerebral blood flow velocity and pulsatility index were measured using pulsed Doppler ultrasound before, during and up to 60 min after the onset fentanyl administration. No significant modification of general or cerebral haemodynamics was observed. In conclusion, the infusion of 3 micrograms/kg of fentanyl did not lead to any deleterious effect on the general or cerebral haemodynamics in sick normovolaemic newborns.

[Pain in hospitalized children]

Pain is present in many hospitalized children and this requires from every physician a constant attention to its recognition, evaluation and treatment. The semeiology of pain differs whether it is acute or chronic. Acute pain can be recognized from its various behavioural, motor and neurovegetative manifestations. Pain evaluation must be adapted according to age: autoevaluation procedures for children older than 5 years, behavioural scales for children younger than 5 years. One must know that there is an appropriate and efficient treatment for each stage of pain intensity. For a better recognition and management of pain in hospitalized children, the organization of teams specialized in the evaluation and treatment of pain in children is to be encouraged.

Issues of assessment of pain and discomfort in neonates

Pain assessment in neonates often presents problems. The problem of inadequate or inaccurate assessment is complicated by issues related to the nature, consistency, and variability of the infant's physiologic and behavioral responses; the reliability, validity, specificity, sensitivity, and practicality of existing neonatal pain measures or measurement approaches; ethical questions about pain research in infants; and uncertainty about the responsibilities of health care professionals in managing pain in clinical settings. Despite these many issues, neonates need to be comfortable and as free of pain as possible to grow and develop normally. Valid and reliable assessment of pain is the major prerequisite for attaining this goal. Issues embodied in neonatal pain responses, measurement, ethical, and clinical considerations are explored. Suggestions for resolving some of these problems are presented.

Pediatric nurses' knowledge and practice related to infant pain

A convenience sample of 181 registered nurses completed questionnaires about their knowledge, attitudes, and clinical practice related to infant pain. The majority of respondents thought infants felt pain with the same intensity as adults and were comfortable administering narcotic and nonnarcotic pain medications. The most frequently identified infant pain cues were: crying, irritability, and inability to be consoled. There were associations between greater numbers of pain cues and higher pain severity ratings and between postlicensure education about pain and number of strategies proposed to relieve pain. There were no associations for noncritical versus critical care unit assignment or participation in postlicensure education about pain with number of assessment cues. There were no associations for pain severity or noncritical versus critical care unit assignment with pain management strategies. Until the research base about management of infant pain is expanded, nurses should continue to use and evaluate a variety of pain management interventions on a case-by-case basis.

The effect of pain on infant behaviors

Facial, body, and cry behaviors, heart rate, palmar sweating, and acoustic cry measures were compared across differing levels of infant pain. Eighty-eight infants were placed in a 16-cell matrix of 4 ages (0 to 3 mo., 4 to 6 mo., 7 to 9 mo., and 10 to 12 mo.) and levels of pain (LOP) (none, mild, moderate, severe) with 5 to 6 infants occupying each cell. Matrix placement was determined by agreement of > 75% among five pediatric clinical nurse specialists who viewed videotapes and read information about the infant's history, diagnosis, medical and/or surgical status, medications, and nutritional/fluid status. Coded infant behaviors and acoustic cry parameters were compared using a 2-level (LOP, age) MANOVA. Behaviors that differed across LOP were influenced by infant development. Facial expressions were clinically useful LOP indicators only for 0- to 3-month-old infants. Facial and body behaviors and cry measures that differed across LOP in younger infants did not differ in older infants due to the development of intentionality. Cry orientation and consolability may be useful clinical indicators of pain with older infants.

The analgesic effect of sucrose in full term infants: a randomised controlled trial

OBJECTIVE

To evaluate the effects of different sucrose concentrations on measures of neonatal pain.

DESIGN

Randomised, double blind, placebo controlled trial of sterile water (control) or one of three solutions of sucrose--namely, 12.5%, 25%, and 50% wt/vol.

SETTING

Postnatal ward.

PATIENTS

60 healthy infants of gestational age 37-42 weeks and postnatal age 1-6 days randomised to receive 2 ml of one of the four solutions on to the tongue two minutes before heel prick sampling for serum bilirubin concentrations.

MAIN OUTCOME MEASURE

Duration of crying over the first three minutes after heel prick.

RESULTS

There was a significant reduction in overall crying time and heart rate after three minutes in the babies given 50% sucrose as compared with controls. This was maximal one minute after heel prick in the 50% sucrose group and became statistically significant in the 25% sucrose group at two minutes. There was a significant trend for a reduction in crying time with increasing concentrations of sucrose over the first three minutes.

CONCLUSION

Concentrated sucrose solution seems to reduce crying and the autonomic effects of a painful procedure in healthy normal babies. Sucrose may be a useful and safe analgesic for minor procedures in neonates.

Differential response to pain by very premature neonates

The ability of very low birth weight (VLBW) premature infants to respond differentially to real versus a sham heelstick conditions was examined in this crossover study. Using a multidimensional assessment of responses of premature infants (n = 48) between 26 and 31 weeks gestational age (GA) at the time of the study, it was found that they respond differentially to real versus sham heelstick both behaviourally and physiologically. The multivariate effect of condition (real/sham) was significant with maximum heart rate and upper facial action (lower facial action was not scored) contributing significantly to the main effect. GA had a main multivariate effect, with the younger infants responding less robustly. The variability outcome measures of heart rate standard deviation and range of transfontanelle intracranial pressure contributed significantly to the main effect of GA, but not to the effect of condition. Young VLBW premature infants are capable of a multidimensional differential response to pain. GA is an important factor to consider when assessing pain in premature infants.

Skin blood flow changes during routine nursery procedures

OBJECTIVE

The objective of this study was to establish that changes in skin blood flow could serve as an index of pain and discomfort in newborn infants.

METHODS

Skin blood flow changes during intensive care procedures and during morphine administration were measured in a group of newborn infants using a laser Doppler technique. Heart rate, respiratory rate and oxygen saturation were also measured. Changes in skin blood flow and physiologic variables that occurred during procedures were analyzed and compared among procedures.

RESULTS

Measurements were made during 145 procedures in 15 infants 2-32 days old with birth weights of 500-2900 g and gestational ages of 23-37 weeks. Ten of the infants were receiving mechanical ventilation. Skin blood flow increased 27-134% during lancet puncture of the heel, physical handling, standard suctioning and chest physiotherapy, and there were no changes during closed system suctioning. Skin blood flow decreased 35% by 20 min after intravenous morphine. Changes seen in heart rate, respiratory rate and oxygen saturation were generally minimal.

CONCLUSIONS

We conclude that laser Doppler skin blood flow changes could be an index of neonatal pain and discomfort; even noninvasive handling procedures are associated with increases in skin blood flow; and changes in skin blood flow may be more useful than conventional physiologic variables in assessing the response to intensive care nursery procedure.

Difficulties in symptom recognition in infants

The subject of symptom recognition in infants is just beginning to be explored in nursing literature; the process may be more difficult that it originally appears. Because symptoms are subjective and their identification is dependent on communication between the client and the nurse or caretaker, it becomes important to assist nurses, parents, and other health care providers in this process. This article discusses the impact of cues, developmental aspects, and inferences as they influence the identification of symptoms experienced by infants.

Ontogenesis of goal-directed behavior: anatomo-functional considerations

Recent neuroanatomical and neurophysiological studies in man have revealed ontogenetic events which coincide with broadly defined phases of behavioral and cognitive development. During the early fetal period, early produced neurons make initial synapses which form the basis for the earliest electrical activity of the human brain. The overall immaturity of neuronal connections, in particularly in cortical areas, correlates with the absence of any behavioral pattern or goal-directed movements. In the late fetus and preterm infant, transient accumulation of major afferent pathways, the presence of transient layers (subplate zone) and transient pattern of transmitter-related organization form the neurological basis of cortical electric responses as well as transient behavioral states and sleep patterns. Parallel to the profound structural and chemical reorganization of the human cerebrum during the first 6 postnatal months there is a disappearance of transient behavioral and motor patterns. The previously close spatio-temporal correlation between these events becomes progressively looser. The overproduction of circuitry elements during the subsequent period peaks in associative cortex between 1 and 2 years of age, corresponding to the emergence of skilled actions and cognitive functions. After the elimination of some circuitry elements after the second year of life, the prolonged maturation of goal-directed behavior and the protracted emergence of different cognitive functions correlates with the development plateau of synapse production which can be seen up to 16 years of age. Parallel to the prolonged maturation of postsynaptic elements, there are well defined maturational changes in the chemical properties of associative pyramidal neurons of cortical layer III. These findings correspond to the prolonged maturation of movement-related brain macropotentials as well as other cognition-related potentials, where the last prominent changes were seen after 10 years of age. Although the coincidence of the developmental events does not necessarily mean a causal relationship, the combination of structural and physiological data opens new vistas for the further investigation of the neurobiological basis of goal-directed movement and cognitive behavior.

Effect of neonatal circumcision on pain responses during vaccination in boys

Using data from one of our randomised trials, we investigated post-hoc whether male neonatal circumcision is associated with a greater pain response to routine vaccination at 4 or 6 months. Pain response during routine vaccination with diphtheria-pertussis-tetanus (DPT) alone or DPT followed by Haemophilus influenzae type b conjugate (HIB) was scored blind. 42 boys received DPT and 18 also received HIB. After DPT, median visual analogue scores by an observer were higher in the circumcised group (40 vs 26 mm, p = 0.03). After HIB, circumcised infants had higher behavioural pain scores (8 vs 6, p = 0.01) and cried longer (53 vs 19 s, p = 0.02). Thus neonatal circumcision may affect pain response several months after the event.

Facilitated tucking: a nonpharmacologic comfort measure for pain in preterm neonates

OBJECTIVE

To identify the effectiveness of "facilitated tucking," a nonpharmacologic nursing intervention, as a comfort measure in modulating preterm neonates' physiologic and behavioral responses to minor pain.

DESIGN

Prospective, repeated measure, random sequencing, and experimental.

SETTING

Level III neonatal intensive-care unit of a tertiary care university pediatric hospital.

PARTICIPANTS

Thirty preterm neonates, 25-35 weeks gestation.

INTERVENTIONS

Heart rate, oxygen saturation, and sleep state were recorded 12 minutes before, during, and 15 minutes after two heelsticks, one with and one without facilitated tucking.

HYPOTHESIS

Premature neonates will have less variation in heart rate and hemoglobin oxygen saturation, shorter crying and sleep disruption times, and less fluctuation in sleep states in response to the painful stimulus of a heelstick with facilitated tucking than without.

RESULTS

Neonates demonstrated a lower mean heart rate 6-10 minutes post-stick (p < 0.04), shorter mean crying time (p < 0.001), shorter mean sleep disruption time (p < 0.001), and fewer sleep-state changes (p = 0.003) after heelstick with facilitated tucking than without.

CONCLUSION

Facilitated tucking is an effective comfort measure in attenuating premature neonates' psychologic and behavioral responses to minor pain.

A comparison of the antinociceptive effects of opioid agonists in neonatal and adult rats in phasic and tonic nociceptive tests

Changes in the attitudes about neonatal pain and pain management have recently resulted in increases in the administration of opioids to neonates. Little is known, however, about the relative potencies of the various opioid agonists employed, especially in comparison to adult responses. The first objective in the present study was to compare the antinociceptive potency of four clinically relevant opioids in neonatal and adult rats. The second objective was to compare and contrast these agents in two different types of nociceptive tests: tonic (formalin-induced inflammation) and phasic (tail flick and hot plate). Our results indicate that the opioid agonists morphine, meperidine, and fentanyl, and the mixed agonist buprenorphine were all effective antinociceptive agents in both neonates and adults in each of the three tests employed, and that the relative potencies of these agents appeared to be similar in neonates and adults. In general, the pups were more sensitive to the antinociceptive agents when tested in the phasic nociceptive tests, and the drugs were more potent in the tonic test than either of the phasic tests.

Plasma beta-endorphin levels and childhood intussusception

To determine whether childhood intestinal intussusception is associated with elevated plasma beta-endorphin levels, a series of patients was studied prospectively. Fourteen patients (age range between 3 months and 7 years) presented to two university pediatric emergency departments in Chicago with clinical symptoms and signs of intussusception. Venous blood (2cc) was withdrawn for plasma beta-endorphin determination, followed by barium enema. Plasma beta-endorphin levels were measured by radioimmunoassay. The mean beta-endorphin level of the 8 patients with barium enema proven intussusception was 14.1 +/- 12.0 pg/ml. Two of these patients presented with marked lethargy and had beta-endorphin levels of 7.5 and 21.2 pg/ml. The mean plasma beta-endorphin level of the 5 patients with negative barium enema studies was 18.1 +/- 10.0 pg/ml (P = 0.56). A sixth control patient had a plasma beta-endorphin level of 1569 pg/ml. In conclusion, childhood intestinal intussusception is not associated with elevated plasma beta-endorphin levels.

Morphine pharmacokinetics in premature and mature newborn infants

The pharmacokinetics of a single dose of morphine was investigated in five term infants (gestational age 37-40 weeks) and eight preterm infants (gestational age 25-32 weeks). In the five term infants, median (range) volume of distribution at steady state (Vd beta) was 1758 (634-2700) ml/kg, plasma clearance (Cl) was 4.73 (1.75-6.61) ml/kg/min and terminal half-life (T1/2) was 224 (107-394) min. In the eight preterm infants, Vd beta was 2366 (1662-2876) ml/kg, Cl was 2.82 (1.88-6.60) ml/kg/min and T1/2 was 556 (248-834) min. No correlation was found between clearance and gestational age, but we found a significant negative correlation between T1/2 and gestational age. We conclude that there is considerable variation in the pharmacokinetic properties of morphine in both term and preterm newborn infants. Because of this variation, careful individual assessment of the clinical effect of therapy with morphine in newborn infants should be exercised.

Placebo-controlled trial of midazolam sedation in mechanically ventilated newborn babies

Although midazolam is used for sedation of mechanically ventilated newborn babies, this treatment has not been evaluated in a randomised trial. We have done a prospective placebo-controlled study of the effects of midazolam on haemodynamic variables and sedation as judged by a five-item behaviour score. 46 newborn babies on mechanical ventilation for respiratory distress syndrome were randomly assigned to receive midazolam (n = 24) or placebo (n = 22) as a continuous infusion. Doses of midazolam were calculated to obtain plasma concentrations between 200 and 1000 ng/mL within 24 h of starting treatment and to maintain these values throughout the study. Haemodynamic and ventilatory variables were noted every hour, as were complications and possible side-effects of treatment. Mean (SD) duration of inclusion was 78.7 (30.9) h. 1 patient in the treatment group and 7 in the placebo group were withdrawn because of inadequate sedation (p < 0.05). Midazolam gave a significantly better sedative effect than placebo, as estimated by the behaviour score (p < 0.05). Heart rate and blood pressure were reduced by treatment but remained within the normal range for gestational age and there was no effect on ventilatory indices. The incidence of complications was similar in the two groups. No midazolam-related side-effects were noted. Continuous infusion of midazolam at doses adapted to gestational age induces effective sedation in newborn babies on mechanical ventilation, with positive effects on haemodynamic variables. The course of the respiratory distress syndrome was not influenced by this treatment. Midazolam was given over only a few days and the limited effects on heart rate and blood pressure that we report should not encourage long-term administration.

Pain sensitivity and temperament in extremely low-birth-weight premature toddlers and preterm and full-term controls

High-technology medical care of extremely low-birth-weight (ELBW) infants (< 1001 g) involves repeated medical interventions which are potentially painful and may later affect reaction to pain. At 18 months corrected age (CCA), we examined parent ratings of pain sensitivity and how pain sensitivity ratings related to child temperament and parenting style in 2 groups of ELBW children (49 with a birth weight of 480-800 g and 75 with a birth weight of 801-1000 g) and 2 control groups (42 heavier preterm (1500-2499 g) and 29 full-birth-weight (FBW) children (> 2500 g). Both groups of ELBW toddlers were rated by parents as significantly lower in pain sensitivity compared with both control groups. The relationships between child temperament and pain sensitivity rating varied systematically across the groups. Temperament was strongly related to rated pain sensitivity in the FBW group, moderately related in the heavier preterm and ELBW 801-1000 g groups, and not related in the lowest birth-weight group (< 801 g). Parental style did not mediate ratings of pain sensitivity. The results suggest that parents perceive differences in pain behavior of ELBW toddlers compared with heavier preterm and FBW toddlers, especially for those less than 801 g. Longitudinal research into the development of pain behavior for infants who experience lengthy hospitalization is warranted.

Fetal plasma cortisol and beta-endorphin response to intrauterine needling

The purpose of this study was to investigate whether the fetus mounts a hormonal stress response to a potentially painful procedure, intrauterine needling. Cortisol and beta-endorphin concentrations in fetal plasma obtained during uncomplicated fetal blood sampling or intrauterine transfusions by needling the fetal intra-abdominal portion of the umbilical vein (intrahepatic vein) were compared to hormone concentrations in fetal plasma obtained by the conventional technique of needling the placental cord insertion, which is not innervated. Cortisol and beta-endorphin concentrations did not increase within 10 minutes of fetal abdominal needling (n = 15). However, more prolonged needling during transfusion at the intrahepatic vein was associated with an increase in fetal plasma cortisol (median increase 48 nmol/L; 95% Cl, 23-86) and beta-endorphin (207 pg/mL; 113-307) concentrations compared to transfusion at the placental cord insertion (p < 0.005 for both hormones). The magnitude of rise in hormone increased linearly with the duration of needling (cortisol, r = 0.80; beta-endorphin, r = 0.88, p < 0.05 for both). These data suggest that the fetus mounts a hormonal stress response to invasive procedures. They raise the possibility that the human fetus feels pain in utero, and may benefit from anaesthesia or analgesia for invasive procedures.

Plasma beta-endorphin concentrations and analgesia-muscle relaxation in the newborn infant supported by mechanical ventilation

We evaluated the effects of pancuronium and opiates on plasma beta-endorphin concentrations in 25 infants supported by mechanical ventilation. Infants receiving opiate were randomly assigned to receive either fentanyl or morphine. There was no change in beta-endorphin concentrations after administration of pancuronium, whereas both fentanyl and morphine reduced beta-endorphin concentrations by approximately 60%.

Sedative-analgesic agent administration in children: analysis of use and complications in the emergency department

The frequency of, indications for, and complications from non-acetaminophen sedative-analgesic agents (SAAs) administered to children less than 16 years of age in the emergency department (ED) were determined by a retrospective review. All 21,353 charts from a single university hospital ED over a 16-month period were included. Few children (N = 759; 3.5%) received SAAs. Of 919 total doses, 13% of children received a second and 4.5% received a third SAA. The group was 59% male. Most children were < or = 10 years of age. Sixty-two percent of SAAs were either sedatives or opioids. Sedatives given included chloral hydrate, diazepam, lorazepam, midazolam, and phenobarbital. Opioids given included morphine, codeine, and meperidine. Indications for SAAs included painful procedures, analgesia, radiographic imaging, and seizure activity. Complications (N = 51; 6.7%) included inadequate sedation, vomiting, and respiratory depression or oxygen desaturation. Respiratory depression or oxygen desaturation occurred only after intravenous administration of SAAs for seizures. In children, non-acetaminophen SAAs are used most commonly in younger patients requiring sedation for painful procedures or for radiologic imaging. Respiratory depression was observed only after intravenous administration of anticonvulsants.

[Specific aspects of perioperative pain relief in children.]

Pain relief in children during the perioperative period can be provided by means of peripherally or centrally acting analgesics or of regional anaesthetic techniques. Narcotics or regional blockde are indicated when peripherally acting analgesics prove inadequate to abolish pain. Side effects of narcotics must be taken into account: opioids must not be administered unless continuous safety monitoring of the child's respiration is assured. If narcotics fail to relieve pain, regional anaesthesia may be indicated. All advantages and drawbacks of the various techniques that might be appropriate must be considered: the technique involving the least risk and side effects is the anaesthetic technique with a broad margin of safety when applied by an anaesthesiologist who has experience with paediatric regional blocks include topical anaesthesia, local infiltration, peripheral nerve blocks (e.g. nervi dorsalis penis, plexus axillaris) and caudal epidural blockade. Caution must be exercised whenever narcotics are administered systemically or epidurally; side effects must not be underestimated, even under conditions of intensive care observation. The provision of effective pain relief is a rewarding task-and particularly in little children.