Drug-induced sleep endoscopy (DISE) has become a routine diagnostic tool to assess the upper airway in obstructive sleep apnea patients, enabling effective diagnosis and appropriate treatment of the obstruction site. A number of protocols with different drugs and availability of target-controlled infusion (TCI) systems have been reported and published, making comparisons between studies difficult. In recent years, dexmedetomidine has claimed a role as a potential alternative to propofol for DISE sedation. In a real-life study we compared the effects of dexmedetomidine continuous infusion or propofol-TCI in patients undergoing DISE on time to reach adequate observation conditions, cardio-respiratory parameters, and recovery.
Pilot prospective, randomized not blinded, single center study. A total of 28 patients scheduled to have DISE were randomly assigned to either group P (N=14; propofol-TCI, initial propofol effect-site target concentration 2.0 µg/mL, increased by 0.3 µg/mL every 2 min) or group D (N=14; dexmedetomidine bolus 1 µg/kg over 10 min, followed by infusion at 0.7 µg/kg/h). Hemodynamic and respiratory variables (including SpO2 nadir), time to reach the observation window and overall DISE duration were recorded.
A total of 28 patients were enrolled and completed the study: the cohort included 26 males (92.85%) and 2 females (7.14%). The mean age was 45.4±11.1 years [interquartile (IQ), 25.0–65.0], body mass index 30.5±3.4 kg/m2 (IQ, 21.0–36.0), and apnea-hypopnea index 36.9±21.1 events/hour (IQ, 7.8–95.0). There were no statistically significant differences between the 2 groups in baseline apnea-hypopnea index, oxygen desaturation index, Epworth Sleepiness Scale score, preprocedural SpO2 nadir, age, sex, or body mass index. Compared with group P, group D showed significant differences in SpO2 (higher nadir during DISE, 87.09±5.4% vs. 75.0±11.0; P<0.001) and heart rate (80.4±8.9 vs. 62.8±6.6; P<0.001). While group D had longer duration of endoscopic examination times and emergence time from sedation, the grading of site of obstructions were similar in the 2 groups.
Dexmedetomidine seems a limited, if viable, clinical alternative for DISE when propofol is contraindicated or not available: while causing higher SpO2 nadirs compared with propofol, it has a slow onset and longer recovery time, increasing total procedural time. Studies with greater patient numbers are needed to confirm these observations.
Drug-induced sleep endoscopy (DISE) has established itself as a diagnostic procedure to identify the pattern of airway obstruction in obstructive sleep apnea (OSA) patients, thus driving the therapeutic decision making process1,2. Choosing the right drug and its administration protocol are crucial in this setting: the aim is to reproduce natural sleep as closely as possible, avoiding or minimizing the effect of the drug on upper airway muscle tone. Among the various drugs used, propofol is the gold standard for its pharmacokinetic profile, allowing a rapid onset and an equally rapid emergence from sedation3. Nevertheless, propofol can cause muscle tone loss, decrease ventilatory drive, and induce respiratory depression in OSA patients. Importantly, sedation induced by propofol does not reproduce physiological sleep4. In the last decade dexmedetomidine, a selective alpha-2 adrenergic receptor agonist reproducing the EEG pattern of physiological sleep without causing respiratory depression, has been considered as possible pharmacological alternative for DISE5,6. Several studies have confirmed the favorable properties of propofol for this procedure, yet there is relative paucity of studies comparing propofol to dexmedetomidine7. Importantly, procedural conditions may vary depending on the type of sedation regimen. We conducted a pilot real-life study comparing procedural conditions under dexmedetomidine continuous infusion with propofol target-controlled infusion (TCI). The primary aim of the study was to compare the effects of dexmedetomidine and propofol on lowest oxygen saturation (SpO2), as this is potentially the most relevant aspect of DISE in terms of safety; the secondary aim was to compare other DISE procedural conditions, namely time to obtain optimal observation, recovery time after sedation, overall procedure time, cardiovascular variables and DISE obstruction sites and grading.
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