A Simulation Study of Propofol Effect-Site Concentration for Appropriate Sedation in Pediatric Patients Undergoing Brain MRI: Pharmacodynamic Analysis

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).

Innovation in sedation and analgesia training

PURPOSE OF REVIEW

We reviewed evidence of recent innovations in sedation education and discuss experiences with sedation training in Taiwan.

RECENT FINDINGS

Current Status of Sedation Training: Didactic training and supervised clinical mentoring are common methods of sedation training. Although training course designed by professional societies to meet individual hospital credentialing requirements, the course content and training expectations vary and are likely inadequate to non-anesthesiologist sedation practitioners. Less Common Forms of Sedation Training: These include screen-based simulation, high-fidelity manikin-based simulation. Screen-based simulation sedation training is popular, convenient, and relatively inexpensive. Although there are numerous courses available, course content has not been standardized. High-fidelity simulation has been accepted to improve knowledge, self-confidence, awareness of emergency, crisis resource management, and teamwork, but it is costly, time intensive, and requires expertise in using simulation equipment. Although screen-based training is attractive and convenient, there is no evidence to suggest that it can replace high-fidelity simulation. Another recently developed education modality is virtual reality simulation. It has gained recent popularity as an immersive approach to medical training, but minimal content has been developed for sedation training. Beyond training, several other potential innovations may improve sedation effectiveness and patient safety. These include adherence to practice guidelines established by professional organizations, utilization of a pre-procedure sedation checklist, interpreting capnography, and implementation of real-time bedside drug displays that provide predictions of concentrations and their associated effects.

SUMMARY

Effective sedation education and training, especially for nonanesthesiologists, is essential to improve patient safety for procedural sedation. Several innovative approaches have been proposed and are relatively early in their development and implementation. Further studies designed to assess the impact of these new training modalities on patient safety and outcomes are warranted.

Sedation Strategies for Procedures Outside the Operating Room

With the rapid development of diagnostic and therapeutic procedures performed outside the operating room (OR), the need for appropriate sedation care has emerged in importance to ensure the safety and comfort of patients and clinicians. The preparation and administration of sedatives and sedation care outside the OR require careful attention, proper monitoring systems, and clinically useful sedation guidelines. This literature review addresses proper monitoring and selection of sedatives for diagnostic and interventional procedures outside the OR. As the depth of sedation increases, respiratory depression and cardiovascular suppression become serious, necessitating careful surveillance using appropriate monitoring equipment.

Future of paediatric sedation: towards a unified goal of improving practice

This review offers a perspective on the future of paediatric sedation. This future will require continued evaluation of adverse events, their risk factors, and predictors. As the introduction of new sedatives with paediatric applications will remain limited, the potential role of mainstay sedatives administered by new routes, for new indications, and with new delivery techniques, should be considered. The role of non-pharmacological strategies for anxiolysis, along with the application of non-mainstay physiologic monitoring, may aid in the improvement of targeted sedation delivery. Understanding the mechanism and location of action of the different sedatives will remain an important focus. Important developments in paediatric sedation will require that large scale studies with global data contribution be conducted in order to support changes in sedation practice, improve the patient experience, and make sedation safer.