Pharmacodynamic Estimate of Propofol-Induced Sedation and Airway Obstruction Effects in Obstructive Sleep Apnea-Hypopnea Syndrome

A Debate on Surgical and Nonsurgical Approaches for Obstructive Sleep Apnea: A Comprehensive Review

Regular and unobstructed breathing during the night is the prerequisite for an undisturbed and restful sleep. The most prevalent nocturnal breathing disturbance with morbid consequences is obstructive sleep apnea syndrome. The prevalence of obstructive sleep apnea (OSA) is increasing, and a significant number of patients with OSA are undiagnosed. On the other hand, the "obesity epidemic" is a growing concern globally. A sleep test is required to diagnose sleep apnea and to individualize therapy. A multidisciplinary approach is the key to success. This narrative review presents a debate on whether surgery is a friend or a foe in the treatment of sleep apnea. Depending on the type and severity of the apnea, the causal factor, and the presence of obesity and hypercapnia as well as the associated pathologies, the optimal therapeutic method is determined for each individual case. The article concludes that each case is unique, and there is no ideal method. Positive pressure ventilation, although a therapeutic gold standard, has its disadvantages extensively discussed in this paper. Nevertheless, it is necessary prior to any surgical intervention, either for the curative treatment of the causal factor of apnea or for elective surgery for another condition. The anesthetic risks associated with the presence of apnea and obesity should not be neglected and should form the basis for decision making regarding surgical interventions for the treatment of sleep apnea.

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

PURPOSE

We aimed to establish the propofol effect-site concentration (Ce) for appropriate sedation by pharmacodynamic analysis and to determine the propofol Ce during occurrence of sedation-related side effects in pediatric patients undergoing brain magnetic resonance imaging (MRI).

MATERIALS AND METHODS

In 50 pediatric patients scheduled for brain MRI, sedation was induced with 2.0 mg/kg propofol; additional propofol doses were 0.5-1 mg/kg. Propofol Ce was simulated by inputting the propofol administration profiles of patients into a pediatric compartmental model (Choi model). The relationship between propofol Ce and probabilities of sedation and recovery were analyzed using a sigmoidal Emax model. The simulated propofol Ce for sedation-related side effects was investigated. Population model parameters were estimated using the Nonlinear Mixed-Effects Modelling software.

RESULTS

The mean values of propofol Ce₅₀ for sedation during the preparation, scanning, and recovery phases were 1.23, 0.43, and 0.39 μg/mL. The simulated propofol Ce values during oxygen desaturation (SpO₂ <90%) (3 patients; 6%), hypotension (16 patients; 32%), and bradycardia (12 patients; 24%) were 3.01±0.04, 2.05±0.63, and 2.41±0.89 μg/mL, respectively.

CONCLUSION

The required propofol Ce₅₀ for applying monitors during the preparation phase before the start of MRI was higher than the propofol Ce₅₀ required during the scanning phase. During low-intensity stimulation phases, such as scanning, propofol bolus dose should be strictly titrated not to exceed the propofol Ce that can lead to oxygen desaturation because of the relatively low propofol Ce (Ce₉₅, 1.43 μg/mL) required for sedation in most patients.