Morphine Pharmacokinetics in Children With Down Syndrome Following Cardiac Surgery

Opioid and benzodiazepine requirements in critically ill post-surgical children with down syndrome: a systematic review and meta-analysis

BACKGROUND

Down syndrome (DS), or Trisomy 21, is defined by the existence of an additional chromosome 21. Various physiological considerations in DS patients might lead to challenges in adequate pain management and sedation after surgery. The aim of this systematic review and meta-analysis is to evaluate the variations of the requirement needed for pain management and sedation in patients with DS who have undergone surgery compared to patients without DS.

METHODS

A systematic review and meta-analysis of studies were conducted, focusing on critically ill patients with DS who were admitted to Intensive care units (ICUs) post-surgery and received opioids and/or benzodiazepines. Searches were conducted in four databases from their inception to November 18, 2023 (Pubmed, Scopus, Cochrane Library, and Web of Science). The primary outcome measured was the dosage of Oral Morphine Equivalent (OME) administered in the days following surgery. Fixed-effect models were used, an approach advisable when only a limited number of studies are available.

RESULTS

Out of the 992 studies initially screened, the systematic review included ten studies, encompassing 730 patients, while the meta-analysis consisted of seven studies, encompassing 533 patients. Of the seven studies included in the analysis, 298 patients were identified to have DS, and 235 patients served as controls. Patients with DS showed a slight increase in OME needs on the first day, but this increase was not statistically significant (mean difference [MD] = 0.09; 95% Confidence Interval [CI]: [-0.02, 0.20]; P = 0.11). There was also no significant difference in the requirement for Midazolam on the first day among DS patients (MD = 0.01; CI [-0.16, 0.19]; P = 0.88). In addition, the duration of mechanical ventilation was not statistically significant in patients with DS compared with the control group (MD = -1.46 hours; 95% CI [-9.74, 6.82]; P = 0.73).

CONCLUSION

Patients with Down syndrome did not require more sedation or analgesia in the first three days after surgery than patients without Down syndrome. Additionally, the two groups showed no significant difference in the duration of mechanical ventilation.

Management of routine postoperative pain for children undergoing cardiac surgery: a Paediatric Acute Care Cardiology Collaborative Clinical Practice Guideline

BACKGROUND

Pain following surgery for cardiac disease is ubiquitous, and optimal management is important. Despite this, there is large practice variation. To address this, the Paediatric Acute Care Cardiology Collaborative undertook the effort to create this clinical practice guideline.

METHODS

A panel of experts consisting of paediatric cardiologists, advanced practice practitioners, pharmacists, a paediatric cardiothoracic surgeon, and a paediatric cardiac anaesthesiologist was convened. The literature was searched for relevant articles and Collaborative sites submitted centre-specific protocols for postoperative pain management. Using the modified Delphi technique, recommendations were generated and put through iterative Delphi rounds to achieve consensus.

RESULTS

60 recommendations achieved consensus and are included in this guideline. They address guideline use, pain assessment, general considerations, preoperative considerations, intraoperative considerations, regional anaesthesia, opioids, opioid-sparing, non-opioid medications, non-pharmaceutical pain management, and discharge considerations.

CONCLUSIONS

Postoperative pain among children following cardiac surgery is currently an area of significant practice variability despite a large body of literature and the presence of centre-specific protocols. Central to the recommendations included in this guideline is the concept that ideal pain management begins with preoperative counselling and continues through to patient discharge. Overall, the quality of evidence supporting recommendations is low. There is ongoing need for research in this area, particularly in paediatric populations.

Dosing of Opioid Medications During and After Pediatric Cardiac Surgery for Children With Down Syndrome

OBJECTIVE

To determine whether children with Down syndrome (DS) receive higher doses of opioid medications compared with children without DS for repair of complete atrioventricular canal (CAVC).

DESIGN

A retrospective chart review of children with and without DS who underwent primary repair of CAVC. The exclusion criteria included unbalanced CAVC and patients undergoing biventricular staging procedures. The primary outcome was oral morphine equivalents (OME) received in the first 24 hours after surgery. The secondary outcomes included intraoperative OME, OME at 48 and 72 hours, nonopioid analgesic and sedative medications received, pain scores, time to extubation, and length of stay.

SETTING

A pediatric academic medical center in the United States.

PARTICIPANTS

One hundred thirty-one patients with DS and 24 without, all <two years old, who underwent a CAVC repair.

INTERVENTIONS

Not applicable.

MEASUREMENTS AND MAIN RESULTS

Patients with DS were older than patients without DS (median 96.3 days [interquartile range {IQR} 70.7-128.2] v 75.9 days [IQR 49.8-107.3], p = 0.033) but otherwise not statistically different in the baseline characteristics. There was no difference in OME received in the first 24 hours postoperatively between groups (3.01 mg/kg [IQR 1.23-5.43] v 3.57 mg/kg [IQR 1.54-7.06], p = 0.202). OME at 48 and 72 hours was lower in the DS group compared with the control group. Similar amounts of opioid and non-opioid analgesics and sedatives were otherwise given to both groups of patients. Median pain scores did not differ between groups.

CONCLUSIONS

These results suggested that patients with DS undergoing CAVC repair do not have increased opioid requirements compared with a similar control group.

Down syndrome and congenital heart disease: perioperative planning and management

Approximately 50% of newborns with Down syndrome have congenital heart disease. Non-cardiac comorbidities may also be present. Many of the principles and strategies of perioperative evaluation and management for patients with congenital heart disease apply to those with Down syndrome. Nevertheless, careful planning for cardiac surgery is required, evaluating for both cardiac and noncardiac disease, with careful consideration of the risk for pulmonary hypertension. In this manuscript, for children with Down syndrome and hemodynamically significant congenital heart disease, we will summarize the epidemiology of heart defects that warrant intervention. We will review perioperative planning for this unique population, including anesthetic considerations, common postoperative issues, nutritional strategies, and discharge planning. Special considerations for single ventricle palliation and heart transplantation evaluation will also be discussed. Overall, the risk of mortality with cardiac surgery in pediatric patients with Down syndrome is no more than the general population, except for those with functional single ventricle heart defects. Underlying comorbidities may contribute to postoperative complications and increased length of stay. A strong understanding of cardiac and non-cardiac considerations in children with Down syndrome will help clinicians optimize perioperative care and long-term outcomes.

Sedation With Midazolam After Cardiac Surgery in Children With and Without Down Syndrome: A Pharmacokinetic-Pharmacodynamic Study

OBJECTIVES

To compare the pharmacokinetics and pharmacodynamics of IV midazolam after cardiac surgery between children with and without Down syndrome.

DESIGN

Prospective, single-center observational trial.

SETTING

PICU in a university-affiliated pediatric teaching hospital.

PATIENTS

Twenty-one children with Down syndrome and 17 without, 3-36 months, scheduled for cardiac surgery with cardiopulmonary bypass.

INTERVENTIONS

Postoperatively, nurses regularly assessed the children's pain and discomfort with the validated COMFORT-Behavioral scale and Numeric Rating Scale for pain. A loading dose of morphine (100 µg/kg) was administered after coming off bypass; thereafter, morphine infusion was commenced at 40 µg/kg/hr. Midazolam was started if COMFORT-Behavioral scale score of greater than 16 and Numeric Rating Scale score of less than 4 (suggestive of undersedation). Plasma midazolam and metabolite concentrations were measured for population pharmacokinetic- and pharmacodynamic analysis using nonlinear mixed effects modeling (NONMEM) (Version VI; GloboMax LLC, Hanover, MD) software.

MEASUREMENTS AND MAIN RESULTS

Twenty-six children (72%) required midazolam postoperatively (15 with Down syndrome and 11 without; p = 1.00). Neither the cumulative midazolam dose (p = 0.61) nor the time elapsed before additional sedation was initiated (p = 0.71), statistically significantly differed between children with and without Down syndrome. Population pharmacokinetic and pharmacodynamics analysis revealed no statistically significant differences between the children with and without Down syndrome. Bodyweight was a significant covariate for the clearance of 1-OH-midazolam to 1-OH-glucuronide (p = 0.003). Pharmacodynamic analysis revealed a marginal effect of the midazolam concentration on the COMFORT-Behavioral score.

CONCLUSIONS

The majority of children with and without Down syndrome required additional sedation after cardiac surgery. This pharmacokinetic and pharmacodynamic analysis does not provide evidence for different dosing of midazolam in children with Down syndrome after cardiac surgery.