Pain, 47 (1991) 3-4 0 1991 Elsevier Science
Publishers
B.V. All rights reserved
0304-3959/91/$03.50
PAIN 01947
Guest Editorial
Second International Symposium on Pediatric Pain, Montreal, April 1991 Donald Tyler ‘, Maria Fitzgerald b, Patrick McGrath ‘, and Patricia A. McGrath d a Department of Anesthesiology, Children S Hospital and Medical Center, University of Washington, School of Medicine, Seattle, WA 98195 (U.S.A.), ’ Department of Anatomy and Developmental Biology, VniL1ersityCollege London, London WCIE 6BT (U.i.K.), ’ Department of Psychology, Dalhousie University, Halifax, NS, B3H 4JI (Canada), and d Children’s Hospital of Western Ontario, Child Health Research Institute, University of Western Ontario, London, Ont., N6C 2V5 (Canada) (Received
and accepted
The Second International Symposium on Pediatric Pain was held in Montreal, Canada on 24-27 April 1991. The most remarkable aspect of the conference was the growth in interest in the field since the first meeting in Seattle in 1988. The number of people working in the field is increasing rapidly, yet the essential nature of the conference remains multidisciplinary. There has also been a change in the aims of workers in the field since 1988 from a group which was trying to prove that children did experience pain and that their pains were generally mismanaged to a group which is now focussed on applying new scientific and clinical advances to the treatment of children in pain. The abstracts were published in the Journal of Pain and Symptom it4unagement. Below we summarize our impressions of the highlights of the meeting from the viewpoint of a pediatric anesthesiologist, a basic scientist, and two clinical psychologists.
Clinical
management
Postoperative pain management was an area that received considerable discussion, and several areas merit comment. Patient-controlled analgesia is commonly used, although the lower age limit of effective use has not been defined. The use of nurse-controlled and parent-controlled analgesia was investigated, but these approaches have seen limited use, and their benefits and risks have not fully been described. The use of new drugs such as ketorolac is starting to be investigated in children, and there were descriptions of the use of routes other than parenteral administration of opioids, including the rectal, oral, and oral transmucosal routes. Epidural administration of opioids remains an important treatment, although the nature and frequency of side effects are limitations in the use of
27 June 1991)
this approach. Continuous epidural infusion of opioids, the use of opioids other than morphine, and the infusion of combinations of opioid and dilute solutions of local anesthetics may provide some relief from side effects, although dosage, infusion rates, potential problems and necessary monitoring have yet to be established. As experience increases with pain management in children, several problem areas have surfaced. The pain of burns, sickle cell disease, and AIDS remains difficult to treat. In addition the management of procedure pain is still a problem, with no clear consensus about how to manage pain of repeated procedures, such as bone marrow aspirations in patients with cancer. Problems of recognition of pain in the hospital setting persist, especially in newborns. While it appears clear that measures are being developed to quantify the response of a newborn infant to a short sharp stimulus, the relevance of that paradigm to measurement of postoperative pain in newborns is questionable. Measurement of pain intensity or even recognition of the presence of pain in the postoperative period in newborns remains a major problem. The number of clinical trials with different patient populations is growing and the quality of the information presented is rapidly improving, but a number of generic problems remain with studies in this field. Results are reported with an insufficient number of patients to allow conclusions to be drawn. The use of non-standard pain intensity measures makes interpretation of data difficult. Retrospective chart reviews for side effects are an appropriate first start, but more definitive information can only come from prospective studies. An appropriate model for evaluation of analgesics is still lacking, although there is some promising work being done in this area.
Basic science
The input from basic scientists into this field is still very small, despite the fact that it is an area where so many exciting issues of interest to developmental neuroscientists are emerging. Studies on the developmental anatomy, neurochemistry, physiology and pharmacology of the peripheral and central nervous system are all highly relevant to the understanding of pain processing in babies and young children. This meeting and the whole area of pediatric pain provides an unusual opportunity to put advances in these basic fields into the context of clinical and psychological findings. Such applications are made possible by the sincerity and genuine eagerness for interdisciplinary collaboration by people in this field. An example of an area that can be directly related to laboratory studies is the change in pain responses or pain experience with age. A number of studies reported at the meeting indicated that pain intensity and pain affect were greater in younger age groups and decreased in older children. This correlates well with physiological findings of lower skin sensory thresholds and exaggerated cutaneous reflexes in immature animals. Localization of pain in young children was reported to be less precise than in older age groups, and this may be related to the large sensory receptive fields recorded in the spinal cord and cortex of immature mammals leading to lack of precision in CNS somatosensory maps. One clear point to emerge from the meeting was the need to investigate the long-term consequences of painful or traumatic peripheral stimulation on the subsequent development of the nervous system. Immature peripheral and central neurons are highly sensitive to damage, and relatively minor injury may lead to substantial and permanent reorganization of the connec-
tions within the CNS. Preliminary results from psychological testing of children who were preterm babies indicate a number of unusual behavior patterns which may be related to this reorganization as well as to psychological factors.
Psychological
studies
The most impressive feature of the psychologically oriented papers was the strong emphasis on development and evaluation of pain measurement. There is increasing psychometric sophistication employed in most studies. Widely used self-report studies are being subjected to more careful validation. In addition, there were a number of studies examining the Neonatal Facial Action Coding System developed by Grunau and Craig. This method is proving to be a very sensitive measure of short sharp pain in neonates. The behavioral measurement of longer term pain e.g., from postoperative pain and from cancer was the subject of a number of papers. There were well designed case-control studies examining social-psychological correlates of somatizing. recurrent abdominal pain and reflex sympathetic dystrophy. These studies may reveal clues to the causes of these disorders. Given the widespread use of psychological interventions and the potential advantages of these interventions in children’s pain, there were surprisingly few well designed trials evaluating their effectiveness. In conclusion the recent meeting showed that the field of pain in infants and children is undergoing rapid growth and evolution and we can anticipate substantial new advancement in our understanding of the underlying biology, measurement and treatment of pediatric pain in the future. A third symposium is planned for 1994.
Publishers
B.V. All rights reserved
0304-3959/91/$03.50
PAIN 01947
Guest Editorial
Second International Symposium on Pediatric Pain, Montreal, April 1991 Donald Tyler ‘, Maria Fitzgerald b, Patrick McGrath ‘, and Patricia A. McGrath d a Department of Anesthesiology, Children S Hospital and Medical Center, University of Washington, School of Medicine, Seattle, WA 98195 (U.S.A.), ’ Department of Anatomy and Developmental Biology, VniL1ersityCollege London, London WCIE 6BT (U.i.K.), ’ Department of Psychology, Dalhousie University, Halifax, NS, B3H 4JI (Canada), and d Children’s Hospital of Western Ontario, Child Health Research Institute, University of Western Ontario, London, Ont., N6C 2V5 (Canada) (Received
and accepted
The Second International Symposium on Pediatric Pain was held in Montreal, Canada on 24-27 April 1991. The most remarkable aspect of the conference was the growth in interest in the field since the first meeting in Seattle in 1988. The number of people working in the field is increasing rapidly, yet the essential nature of the conference remains multidisciplinary. There has also been a change in the aims of workers in the field since 1988 from a group which was trying to prove that children did experience pain and that their pains were generally mismanaged to a group which is now focussed on applying new scientific and clinical advances to the treatment of children in pain. The abstracts were published in the Journal of Pain and Symptom it4unagement. Below we summarize our impressions of the highlights of the meeting from the viewpoint of a pediatric anesthesiologist, a basic scientist, and two clinical psychologists.
Clinical
management
Postoperative pain management was an area that received considerable discussion, and several areas merit comment. Patient-controlled analgesia is commonly used, although the lower age limit of effective use has not been defined. The use of nurse-controlled and parent-controlled analgesia was investigated, but these approaches have seen limited use, and their benefits and risks have not fully been described. The use of new drugs such as ketorolac is starting to be investigated in children, and there were descriptions of the use of routes other than parenteral administration of opioids, including the rectal, oral, and oral transmucosal routes. Epidural administration of opioids remains an important treatment, although the nature and frequency of side effects are limitations in the use of
27 June 1991)
this approach. Continuous epidural infusion of opioids, the use of opioids other than morphine, and the infusion of combinations of opioid and dilute solutions of local anesthetics may provide some relief from side effects, although dosage, infusion rates, potential problems and necessary monitoring have yet to be established. As experience increases with pain management in children, several problem areas have surfaced. The pain of burns, sickle cell disease, and AIDS remains difficult to treat. In addition the management of procedure pain is still a problem, with no clear consensus about how to manage pain of repeated procedures, such as bone marrow aspirations in patients with cancer. Problems of recognition of pain in the hospital setting persist, especially in newborns. While it appears clear that measures are being developed to quantify the response of a newborn infant to a short sharp stimulus, the relevance of that paradigm to measurement of postoperative pain in newborns is questionable. Measurement of pain intensity or even recognition of the presence of pain in the postoperative period in newborns remains a major problem. The number of clinical trials with different patient populations is growing and the quality of the information presented is rapidly improving, but a number of generic problems remain with studies in this field. Results are reported with an insufficient number of patients to allow conclusions to be drawn. The use of non-standard pain intensity measures makes interpretation of data difficult. Retrospective chart reviews for side effects are an appropriate first start, but more definitive information can only come from prospective studies. An appropriate model for evaluation of analgesics is still lacking, although there is some promising work being done in this area.
Basic science
The input from basic scientists into this field is still very small, despite the fact that it is an area where so many exciting issues of interest to developmental neuroscientists are emerging. Studies on the developmental anatomy, neurochemistry, physiology and pharmacology of the peripheral and central nervous system are all highly relevant to the understanding of pain processing in babies and young children. This meeting and the whole area of pediatric pain provides an unusual opportunity to put advances in these basic fields into the context of clinical and psychological findings. Such applications are made possible by the sincerity and genuine eagerness for interdisciplinary collaboration by people in this field. An example of an area that can be directly related to laboratory studies is the change in pain responses or pain experience with age. A number of studies reported at the meeting indicated that pain intensity and pain affect were greater in younger age groups and decreased in older children. This correlates well with physiological findings of lower skin sensory thresholds and exaggerated cutaneous reflexes in immature animals. Localization of pain in young children was reported to be less precise than in older age groups, and this may be related to the large sensory receptive fields recorded in the spinal cord and cortex of immature mammals leading to lack of precision in CNS somatosensory maps. One clear point to emerge from the meeting was the need to investigate the long-term consequences of painful or traumatic peripheral stimulation on the subsequent development of the nervous system. Immature peripheral and central neurons are highly sensitive to damage, and relatively minor injury may lead to substantial and permanent reorganization of the connec-
tions within the CNS. Preliminary results from psychological testing of children who were preterm babies indicate a number of unusual behavior patterns which may be related to this reorganization as well as to psychological factors.
Psychological
studies
The most impressive feature of the psychologically oriented papers was the strong emphasis on development and evaluation of pain measurement. There is increasing psychometric sophistication employed in most studies. Widely used self-report studies are being subjected to more careful validation. In addition, there were a number of studies examining the Neonatal Facial Action Coding System developed by Grunau and Craig. This method is proving to be a very sensitive measure of short sharp pain in neonates. The behavioral measurement of longer term pain e.g., from postoperative pain and from cancer was the subject of a number of papers. There were well designed case-control studies examining social-psychological correlates of somatizing. recurrent abdominal pain and reflex sympathetic dystrophy. These studies may reveal clues to the causes of these disorders. Given the widespread use of psychological interventions and the potential advantages of these interventions in children’s pain, there were surprisingly few well designed trials evaluating their effectiveness. In conclusion the recent meeting showed that the field of pain in infants and children is undergoing rapid growth and evolution and we can anticipate substantial new advancement in our understanding of the underlying biology, measurement and treatment of pediatric pain in the future. A third symposium is planned for 1994.
