Factors Associated With Recovery Room Intravenous Opiate Requirement After Pediatric Outpatient Operations

Olubukola O. Nafiu, MD, FRCA, MS; Aleda Thompson, MS; S. Devi Chiravuri, MD; Benjamin Cloyd, MD; Paul I. Reynolds, MD


Anesth Analg. 2019;128(6):1225-1233. 

In This Article

Abstract and Introduction


Background: Many children recovering from anesthesia experience pain that is severe enough to warrant intravenous (IV) opioid treatment within moments of admission to the postanesthesia care unit (PACU). Postoperative pain has several negative consequences; therefore, preventing significant PACU pain in children is both a major clinical goal and a moral/ethical imperative. This requires identifying patient-level and perioperative factors that may be used to predict PACU IV opioid requirement. This should allow for the development of personalized care protocols to prevent clinically significant PACU pain in children. Our objective was to develop prediction models enabling practitioners to identify children at risk for PACU IV opioid requirement after various painful ambulatory surgical procedures.

Methods: After Institutional Review Board approval, clinical, demographic, and anthropometric data were prospectively collected on 1256 children 4–17 years of age scheduled for painful ambulatory surgery (defined as intraoperative administration of analgesia or local anesthetic infiltration). Three multivariable logistic regression models to determine possible predictors of PACU IV opioid requirement were constructed based on (1) preoperative history; (2) history + intraoperative variables; and (3) history + intraoperative variables + PACU variables. Candidate predictors were chosen from readily obtainable parameters routinely collected during the surgical visit. Predictive performance of each model was assessed by calculating the area under the respective receiver operating characteristic curves.

Results: Overall, 29.5% of patients required a PACU IV opioid, while total PACU analgesia requirement (oral or IV) was 41.1%. Independent predictors using history alone were female sex, decreasing age, surgical history, and non-Caucasian ethnicity (model area under the receiver operating characteristic curve [AUROC], 0.59 [95% confidence interval {CI}, 0.55–0.63]). Adding a few intraoperative variables improved the discriminant ability of the model (AUROC for the history + intraoperative variables model, 0.71 [95% CI, 0.67–0.74]). Addition of first-documented PACU pain score produced a substantially improved model (AUROC, 0.85 [95% CI, 0.82–0.87]).

Conclusions: Postoperative pain requiring PACU IV opioid in children may be determined using a small set of easily obtainable perioperative variables. Our models require validation in other settings to determine their clinical usefulness.


Despite ongoing advances in pediatric anesthesia and perioperative care, clinically significant postoperative pain (POP) remains a common problem, even after procedures that may be considered relatively "inconsequential." Indeed, many children recovering from even the most minor ambulatory surgical procedure experience pain that is severe enough to warrant treatment with opioids in the postanesthesia care unit (PACU).[1,2] Acute POP increases overall complication rates, prolongs PACU and hospital stay, delays ambulation, may cause unplanned hospital admission, and may increase the overall cost of hospitalization.[3–6] Additionally, severe PACU pain delays the time children are reunited with their parents after surgery leading to patient/family disappointment.[7] Moreover, children recovering with substantial pain and discomfort place considerable burden on the PACU nurses due to the need for treatment and the possible side effects associated with potent analgesic medications (such as opioids). Finally, severity of acute POP and opioid consumption are important determinants of chronic postsurgical pain,[8,9] a major predictor of new persistent opioid use.[10] To this end, preventing significant pain after ambulatory surgery is both a major clinical goal and a moral/ethical imperative.

Acute POP is influenced by a wide variety of largely unknown factors in the pediatric ambulatory surgical population. Prospective identification of children who are at risk for PACU pain requiring opioid analgesics is highly desirable because this could guide practitioners to administer appropriate interventions either preemptively or in the early recovery phase of anesthesia. This should help reduce the burden of caring for children with acute pain in the PACU. Furthermore, given the wide interindividual variability in opioid requirements and biotransformation,[11,12] there is increasing concern that administering opioid analgesia to some children in the PACU could significantly increase their risk for postoperative respiratory depression at home.[11] Respiratory depression from opioids is an important clinical problem that impedes safe delivery of pain relief especially in children undergoing ambulatory surgical procedures.[11]

Given the growing number and complexity of pediatric outpatient procedures,[13] a priori identification of predictors of PACU pain requiring supplemental opioid analgesia is an important clinical goal. To date, these factors are largely unknown in pediatric ambulatory surgical patients. Consequently, the objectives of this prospective, observational study were to determine the incidence and risk factors associated with clinically significant PACU pain (indicated by PACU intravenous [IV] opioid requirement) among children who underwent various painful elective ambulatory surgical procedures. We tested the hypothesis that POP experience, assessed by PACU IV opioid requirement, is associated with identifiable baseline clinical differences in children undergoing elective ambulatory surgery.