This study demonstrates that African American and Caucasian children exhibit significant differences in postoperative pain responses, postoperative opioid requirements, and opioid adverse effects after tonsillectomy or adenotonsillectomy. African American race is associated with higher maximum postoperative pain scores and greater postoperative morphine requirements, whereas Caucasian race is associated with higher incidence of opioid related adverse effects despite lower morphine requirement. Importantly, these differences were independent of OSA.
In our study, African American children had significantly higher postoperative pain scores and received more morphine than Caucasian children. The higher pain scores in African American children are consistent with adult studies.17–21
An experimental study in children examined the influence of race on children’s pain sensitivity and revealed a differential moderating effect of pain coping and pain sensitivity between African American and Caucasian children.22
Authors of previous studies have demonstrated that African American patients have disproportionally inadequate pain control than Caucasian patients.6,9,23
We showed that African American and Caucasian children receiving similar doses of morphine during surgery have different postoperative pain experience for the same surgical procedure.
Racial disparities in pain management have been reported in emergency department,9
and postsurgical pain management.5
Though these studies6,9,23
suggest that there is under treatment of African American patients leading to inadequate pain control, our study indicates that African American children have intrinsically higher morphine requirements for comfort after surgery. African American children had higher postoperative pain scores in the PACU after receiving identical morphine doses to Caucasian children.
We also found that African American children had lower levels of side effects and increased tolerance of higher morphine doses than Caucasian children. Overall incidences of opioid related side effects in the PACU and incidences of prolonged PACU stay due to side effects were higher in Caucasian children compared with African American children, despite Caucasian children receiving relatively lower total perioperative opioid dose than African American children (). Though a few children had clinical respiratory depression with higher doses of opioid, in our monitored PACU setting, none of the participants had serious harm or required re-intubation, naloxone use, or extended ventilator support.
Tonsillectomy and adenotonsillectomy are a common surgical treatment of recurrent tonsillitis and OSA in children.24
OSA is a common indication for adenotonsillectomy in children. African Americans have higher incidence of OSA than Caucasian patients,25
which was observed in this study’s pediatric population as well. Postsurgical administration of opioids in patients with OSA has recently been linked to an increased risk for respiratory complications.26
It is recommended that the total opioid dose to ensure adequate analgesia is about half in children with OSA compared with those with no OSA history.24
Paradoxically, in our study we observed significantly higher incidence of opioid related adverse effects in Caucasian children than African American children.
Because of this increased sensitivity to morphine related adverse effects in children with OSA, children in our study who presented for tonsillectomy due to OSA had lower intraoperative morphine doses compared with those presented for recurrent tonsillitis. Despite controlling for OSA in the study design, a history of OSA appears to be associated with increased pain and analgesic requirement in African American children. Our results indicate that reducing morphine dose is reasonable practice for Caucasian patients with OSA but may be leading to more pain related complications postoperatively in African American children with OSA.
In our follow-up and related study, we observed that African American children have higher morphine clearance than Caucasian children. Common UGT2B7 genetic variations (−161C>T and 802C>T) were not associated with observed racial differences in morphine’s clearance although the wild type of the UGT2B7 isozyme is more prevalent in the African American patients. Race of the child is an important factor in perioperative intravenous morphine’s clearance, and its potential role in personalizing analgesia with morphine needs further investigation (S.S., personal communication 2012).
There are a few limitations in our study. Although our study revealed an association between race and postoperative pain perception and responses to perioperative opioid, it is not possible to say whether these differences are related to race per se or to some unknown or not measurable variables that are highly associated with race, such as socioeconomic status, pain coping skills, and unknown genetic factors. Secondly, due to local demographics, we enrolled mainly African American and Caucasian children. Our current study does not address other races, especially the growing Hispanic population. Inclusion of other races/ethnicities is necessary to generalize and personalize perioperative outcomes based on race and ethnicity. Lastly, variations among clinical care providers such as PACU nurses and their subjective bias toward children’s pain perception and comfort level with opioid doses and responses might have influenced the results because of the observational nature of this prospective study. Findings from a large national study to describe pediatric nurses’ projected responses to children’s pain suggest that most nurses would make appropriate decisions relating to the treatment of children’s pain.27
Because intraoperative doses of morphine in both races were the same, only postoperative doses differed between races. The differences in dosing are based on postoperative pain scores; thus we believe the data to be free of racial bias.
Accurate measures of pain intensity are needed if postoperative pain is to be adequately managed while avoiding potentially harmful side effects. Difficulties in communication with children especially after surgery while recovering from anesthesia can compromise subjective pain assessment. The NRS is a self-reported pain score. In addition to subjective pain scores, we used an objective pain score, FLACC score, to measure pain in children. The FLACC scale uses behavioral cues to evaluate the degree of pain, and it is unknown if children of different ethnic backgrounds behave differently in response to pain.