The administration of high-dose propofol sedation with manual and target-controlled infusion in children undergoing radiation therapy: a 7-year clinical investigation

Survey of Anesthesia, Sedation, and Non-sedation Practices for Children Undergoing Repetitive Cranial or Craniospinal Radiotherapy

Background

Children undergoing cranial or craniospinal radiotherapy may require over 30 treatments within a six-week period. Facilitating these many treatments with the patient under anesthesia presents a significant challenge, and the most preferred anesthetic methods remain unknown. The primary goal of this study was to determine the most preferred anesthetic methods and agents for children undergoing daily cranial or craniospinal radiotherapy.

Methods

An 83-item web-based survey was developed. An introductory email was sent to 505 physicians and child-life specialists with expertise in pediatric anesthesia and/or affiliated with pediatric radiation oncology departments.

Results

The response rate was 128/505 (25%) and included specialists from Africa (5, 4%), Asia (18, 14%), Australia/Oceania (5, 4%), Europe (45, 35%), North America (50, 39%), and South America (5, 4%). The 128 respondents included 91 anesthesiologists (71%), 20 physicians who were not anesthesiologists (16%), 14 child life/social education specialists (11%), one radiotherapist, one pediatric radiation nurse, and one non-specified medical professional (all = 2%). Of the 128 respondents, 95 (74%) used anesthesia or sedation to facilitate repetitive cranial or craniospinal radiotherapy. Overall, total intravenous anesthesia without intubation was preferred by 67 of 95 (71%) specialists during one or more forms of radiotherapy. During photon-based radiotherapy, total intravenous anesthesia without intubation was the preferred anesthetic method with the patient in the supine (57/84, 68%) and prone positions (25/40, 63%). Propofol was the most used anesthetic agent for both supine (73/84, 87%) and prone positions (38/40, 95%). For proton radiotherapy, total intravenous anesthesia without intubation was the most preferred anesthetic method for the supine (32/42, 76%) and prone treatment positions (11/18, 61%), and propofol was the most used anesthetic (supine: 40/43, 93%; prone: 16/18, 89%).

Conclusions

In this survey of 95 specialists responsible for anesthesia or sedation of children undergoing repetitive cranial or craniospinal radiotherapy, propofol-based total intravenous anesthesia without intubation was the preferred anesthetic technique.

The relationship between the effect-site concentration of propofol and sedation scale in children: a pharmacodynamic modeling study

Background

Continuous infusion of propofol has been used to achieve sedation in children. However, the relationship between the effect-site concentration (C_e) of propofol and sedation scale has not been previously examined. The objective of this study was to investigate the relationship between the C_e of propofol and the University of Michigan Sedation Scale (UMSS) score in children with population pharmacodynamic modeling.

Methods

A total of 30 patients (aged 3 to 6 years) who underwent surgery under general anesthesia with propofol and remifentanil lasting more than 1 h were enrolled in this study. Sedation levels were evaluated using the UMSS score every 20 s by a 1 μg/mL stepwise increase in the C_e of propofol during the induction of anesthesia. The pharmacodynamic relationship between the C_e of propofol and UMSS score was analyzed by logistic regression with nonlinear mixed-effect modeling.

Results

The estimated C_e50 (95% confidence interval) of propofol to yield UMSS scores equal to or greater than n were 1.84 (1.54–2.14), 2.64 (2.20–3.08), 3.98 (3.66–4.30), and 4.78 (4.53–5.03) μg/mL for n = 1, 2, 3, and 4, respectively. The slope steepness for the relationship of the C_e versus sedative response to propofol (95% confidence interval) was 5.76 (4.00–7.52).

Conclusions

We quantified the pharmacodynamic relationship between the C_e of propofol and UMSS score, and this finding may be helpful to predict the sedation score at the target C_e of propofol in children.

Trial registration

http://www.clinicaltrials.gov (No.: NCT03195686, Date of registration: 22/06/2017).

Incidence of tolerance in children undergoing repeated administration of propofol for proton radiation therapy: a retrospective study

Background

Propofol is an excellent hypnotic drug for use in repeated radiation procedures in young children. To date, tolerance to propofol generally does not develop in pediatric patients undergoing radiation therapy. However, several studies have suggested that there may be potential for development of tolerance to propofol. The aim of this study was to evaluate the development of a tolerance to propofol used for repeated deep sedation in children undergoing proton radiation therapy (PRT).

Methods

All children undergoing PRT at our institution between December 2015 and January 2018 were eligible for inclusion in this study. Sedation was induced by a bolus dose of propofol (2.0 mg.kg^− 1) followed by a continuous infusion of 250 μg.kg^− 1.min^− 1 via an infusion pump to achieve deep sedation. Sedation was maintained with the propofol infusion of 200 μg.kg^− 1.min^− 1, which was adjusted in 25 μg.kg^− 1.min^− 1 increments up or down as necessary to ensure deep sedation. The primary outcome was mean doses of propofol over time.

Results

Fifty-eight children were analyzed. The mean (SD) age was 4.5 (2.1) years. The mean (SD) number of treatment sessions was 19 (7). Fifteen patients (26%) developed tolerance to propofol. However, there were no significant differences between the children who developed tolerance and the children who did not develop tolerance in mean propofol dose and awakening time over time (p = 0.887 and P = 0.652, respectively). Age, the number of PRT, and attending anesthesiologists was not significantly associated with the incidence of tolerance to propofol.

Conclusion

Repeated prolonged deep sedation for PRT elicited multiple times over several weeks in young children using propofol did not develop tolerance in 74% of patients. Although the incidence of 26% tolerance to propofol may still be present, the increase in propofol dose was minimal. Therefore, the use of repeated propofol for children was safe.

Factors affecting propofol dosage for sedation in pediatric oncology

BACKGROUND

There is limited reference data for determining the appropriate dose of propofol for individual patients. Therefore, we investigated the factors affecting propofol dosage for pediatric patients undergoing sedation for computed tomography (CT) simulation.

METHODS

We retrospectively analyzed the electronic medical records of pediatric patients who underwent CT simulation for proton therapy following a cancer diagnosis at the National Cancer Center (Korea) between 1 May 2012 and 30 April 2016. We evaluated the following factors, which reflect comorbidities or chronic illness in pediatric oncology patients: age, tumor lesion, preterm birth, American Society of Anesthesiologists (ASA) classification, pre-sedation temperature, history of propofol use, nothing by mouth time, chemotherapy history, pre-sedation laboratory findings, regular medication (opioids, anticonvulsants), and use of diuretics. A regression analysis was performed and P < 0.05 was considered statistically significant.

RESULTS

Electronic medical records of 84 pediatric cancer patients were used in the analysis. Patients in ASA classes 1-2 required approximately 43% more propofol than patients in classes 3-4 (exp(β), 1.43; 95%CI: 1.21-1.69, P < 0.001).

CONCLUSION

American Society of Anesthesiologists class 3 or 4 is an independent indicator of decreased propofol dosage for pediatric oncology patients during sedation.