Postoperative pain expression in preschool children: validation of the child facial coding system

Validation of the Parents' Postoperative Pain Measure in Finnish children aged 1-6 years

The Canadian Parents' Postoperative Pain Measure (PPPM) is a behavioural pain measure for children. The purpose of this study was to test validity and reliability of this measure in 1-6-year-old Finnish children at home after minor day surgery. Children (n = 85) and their parents from four hospitals were included in the sample. The parents, mostly mothers (93%), filled in at home a questionnaire including PPPM during the day of operation, and the first and second postoperative days. Parents (n = 85) rated the presence or absence of behavioural changes from a checklist and also the child's worst pain during each day (using a Visual Analogue Scale, VAS). The response rate was 58. Principal component factor analysis, testing of correlation coefficient, cross-tabulations and Cronbach's alpha were used to test the instrument. The findings showed that construct validity of the measure was satisfactory. The PPPM was successful in discriminating between children who had no/low pain and children who had a clinically significant pain measured by VAS (convergence validity). Scores on the PPPM decreased from days 0 to 1 and from days 1 to 2 (predictive validity). Internal consistency of the measure and correlations with the pain scores on VAS were high on all days following surgery (equivalence). Sensitivity was satisfactory only when specificity was weaker. The findings of this study can be utilized in the development of children's postoperative pain assessment at home. However, further studies are needed to test the instrument in larger samples.

An admixture of 3 mg x kg(-1) of propofol and 3 mg x kg(-1) of thiopentone reduces pain on injection in pediatric anesthesia

PURPOSE

To evaluate the incidence of pain on injection in children during anesthetic induction with a 3:1.2 volume admixture of 1% propofol and 2.5% thiopentone (P/T) compared to a 10:1 volume admixture of 1% propofol and 2% lidocaine (P/L).

METHODS

After Ethics Committee approval and informed written parental consent, 127 children, aged one to ten years were studied and randomized into two groups; Group P/L received an induction with 5 mg x kg(-1) of 1% propofol and 1 mg x kg(-1) of lidocaine, Group P/T with 3 mg x kg(-1) of 1% propofol and 3 mg x kg(-1) of 2.5% thiopentone in a standardized fashion. A single, blinded observer scored pain behaviour defined as a motor response of the arm, a verbal complaint of pain, cry and/or one of three standardized facial expressions of pain.

RESULTS

The incidence of pain was 14% in the P/T group, compared to 35% in the P/L group (chi(2)(1) = 7.5, P = 0.006). Motor response was the most frequent pain response in the P/L group (68%).

CONCLUSION

The P/T admixture is a practical and efficacious alternative to P/L for reducing pain on induction in children. Further work to evaluate the optimum proportions and possible adverse effects of this admixture should be done.

Are postoperative pain instruments useful for specific groups of vulnerable infants?

Based on the authors' review of the literature on pediatric postoperative pain assessment with special attention to groups of vulnerable infants, this article (1) reports on type of surgery and its relationship to postoperative pain intensity; (2) reviews the characteristics of existing postoperative pain instruments for neonates, infants, and toddlers; (3) discusses timing, duration, and who should assess postoperative pain; (4) reviews the specific literature on pain assessment in critically ill infants, including the extremely low birth weight and the cognitively and/or neurologically impaired infant, and (5) discusses the role of parents in postoperative pain assessment. Postoperative pain instruments are useful for specific groups of vulnerable infants, but it is important that in addition to the valuable scoring of pain, common sense is used and factors such as developmental stage, temperament and personality, number of previous painful experiences, anxiety, and environmental factors are taken into account.

Efficacy of continuous versus intermittent morphine administration after major surgery in 0-3-year-old infants; a double-blind randomized controlled trial

A randomized double-blind clinical trial compared the efficacy of 10 microg/kg/h morphine continuous intravenous infusion (CM) with that of 30 microg/kg morphine (IM) every 3h after major abdominal or thoracic surgery, in 181 infants aged 0-3 years. Efficacy was assessed by the caregiving nurses with the COMFORT 'behavior' and a visual analogue scale (VAS) for pain, every 3h in the first 24h after surgery. Random regression modeling was used to simultaneously estimate the effect of randomized group assignment, actual morphine dose (protocol dosage plus extra morphine when required), age category, surgical stress, and the time-varying covariate mechanical ventilation on COMFORT 'behavior' and the observational VAS rated pain, respectively. Overall, no statistical differences were found between CM and IM morphine administration in reducing postoperative pain. A significant interaction effect of condition with age category showed that the CM assignment was favorable for the oldest age category (1-3 years old). The greatest differences in pain response and actual morphine dose were between neonates and infants aged 1-6 months, with lower pain response in neonates who were on average satisfied with the protocol dosage of 10 microg/kg/h. Surgical stress and mechanical ventilation were not related to postoperative pain or morphine doses, leaving the inter-individual differences in pain response and morphine requirement largely unexplained.

Watch Needle, Watch TV: Audiovisual Distraction in Preschool Immunization

OBJECTIVE

To evaluate the effectiveness of audiovisual distraction compared with a blank TV screen in the reduction of pain associated with intramuscular immunization.

DESIGN

Subjects were randomly assigned to watch television (TV) (N = 29) or a blank TV screen (control) (N = 33) during immunization, and were videotaped. Immediately after the injection, the children rated their pain. Videotapes were coded for pain behaviors and for distraction. t tests determined between-group mean differences and chi-square tests compared proportions for clinically significant self-reported pain.

SETTING

Two urban pediatric practices in Halifax, Nova Scotia, Canada.

SUBJECTS

Five-year-old children (N = 62), undergoing diphtheria, polio, tetanus, and pertussis immunization, and their parents.

INTERVENTIONS

An age-appropriate musical cartoon or a blank TV screen.

OUTCOME MEASURES

Pain measurements were the children's self-reports on Faces Pain Scale, facial actions on Child Facial Coding System, and Children's Hospital of Eastern Ontario Pain Scale. Distraction was measured by mean time spent watching the TV screen. Parents rated their own and their child's anxiety on a visual analogue scale.

RESULTS

There were no significant group differences for any pain or distraction measures. The relative risk estimate for clinically significant pain among the distraction group was 0.64 (range: 0.23-1.80). Higher levels of distraction (i.e., greater time looking at the TV screen) related to lower levels of pain on all three pain measures. Only correlations with objective pain measures were statistically significant.

CONCLUSIONS

Watching cartoons did not distract children during needle injection nor reduce their pain. Looking at the TV screen was related to lower behavioral pain scores in the total sample.

A theoretical framework for understanding self-report and observational measures of pain: a communications model

Self-report and observational measures of pain are examined from the perspective of a model of human communication. This model examines the experience of pain as affected by intrapersonal and contextual factors, the process whereby it is encoded into expressive behaviour, and the process of decoding by observers prior to their engaging in action. Self-report measures primarily capture expressive pain behaviour that is under the control of higher mental processes, whereas observational measures capture behaviour that is less subject to voluntary control and more automatic. Automatic expressive behaviours are subject to less purposeful distortion than are behaviours dependent upon higher mental processes. Consequently, observational measures can be used and have clinical utility as indices of pain when self-report is not available, for example, in infants, young children, people with intellectual disabilities or brain damage, and seniors with dementia. These measures are also useful when the credibility of self-report is questioned and even when credible self-report is available. However, automatic behaviours may be more difficult for observers to decode. The model outlined herein takes into account the role of various human developmental stages in pain experience and expression and in understanding the utility of self-report and observational measures. We conclude that both observational and self-report measures are essential in the assessment of pain because of the unique information that each type contributes.

Nursing staff members' perceptions of pain indicators in persons with severe dementia

OBJECTIVES

The aims of this study were to (1) identify behaviors that occur in noncommunicative nursing home residents that are perceived by nurses to be indicators of pain, (2) determine factors affecting the differentiation of pain behaviors from similar behaviors due to other causes, and (3) assess nurses' perceptions of the prevalence and importance of specific indicators of pain as well as barriers to the detection of pain in this population.

SETTING AND PATIENTS

Seventy-two staff members of three nursing homes were interviewed and surveyed about specific behaviors associated with pain. Focus groups were conducted with staff to validate pain indicators and investigate perceptions of their own ability to identify pain.

RESULTS

Nursing staff members agreed on a core group of behaviors that they perceive as pain indicators in elderly persons suffering from dementia. These indicators include specific physical repetitive movements, vocal repetitive behaviors, physical signs of pain, and changes in behavior from the norm for that person. The nursing staff members' level of familiarity with the residents was reported to have a significant effect on staff members' ability to identify and differentiate pain behaviors from other behaviors of impaired residents. Barriers to the detection of pain pertain to staff issues, resident behaviors, and resident-staff relationships.

CONCLUSIONS

The study of pain among the noncommunicative elderly and, in particular, the development of a tool that can be used to assess their pain may greatly improve the quality of life of the estimated 20% to 35% of nursing home residents who cannot adequately express their needs.

Facial expression of children receiving immunizations: a principal components analysis of the child facial coding system

OBJECTIVE

To identify the structure of facial reaction to procedural pain and to determine the subset of facial actions that best describe the response.

DESIGN

Observational.

SETTING

Five rural and five urban physicians' offices.

PATIENTS

One hundred twenty-three children aged 4 to 5 years undergoing routine diphtheria, pertussis, tetanus, and polio immunization.

OUTCOME MEASURES

The Child Facial Coding System, comprising 13 discrete facial actions, was used to code each second of five 10-second phases from videotape: baseline, preneedle, needle, postneedle, and posthandling. Parents and a technician provided visual analog scale ratings of children's pain. Children provided a self-report using a Faces Pain Scale, and parents and nurses rated the children's pain and anxiety using visual analog scales.

RESULTS

A "pain face" similar to that reported in adults emerged with the onset of pain. Principal component analyses revealed the frequency and intensity of facial action during the needle phase could be represented by components reflecting pain sensation, a "brave face," and the children's expectations for pain. Children's Faces Pain Scale and adult visual analog scale ratings were best predicted by components reflecting pain sensation and expectations of high pain.

CONCLUSIONS

These results provide a preliminary indication that the Child Facial Coding System can be reduced to components that reflect several aspects of children's acute pain experience and predict self-reports and observer reports of children's pain.