Drug-Induced Sleep Endoscopy (DISE) with Target Controlled Infusion (TCI) and Bispectral Analysis in Obstructive Sleep Apnea

The overall goal of this procedure is to establish a standardized and reproducible protocol for drug-induced sleep endoscopy for heterogeneous groups of patients with obstructive sleep apnea to differentiate obstruction patterns to enable and improve individualized treatment. This method can help to differentiate obstruction patterns even in heterogeneous groups of patients with obstructive sleep apnea by using a standardized, and reproducible protocol. The main advantage of this technique is the target controlled infusion, or TCI of the sedative can be combined with real-time bispectral analysis to precisely control patient sedation.

Generally, examiners knew the drug induce sleep endoscopy would struggle. With inducing the desired depth of sedation, leading to an unintentional deep sedation, followed by consecutive apnea, hypoxia, or hypertension. Begin by helping the patient into the supine position on the operating table.

Then have the anesthesiologist connect the vital sign monitoring system on the left side of the patient, and wipe the patient's forehead with disinfectant. When the skin is dry, position a sensor with four interconnected and adhesive electrodes diagonally on the patient's forehead with one electrode at the center of the forehead, one directly above each eyebrow, and one on the temple between the corner of one eye and hairline. When all of the electrodes are in place, connect the sensor interface cable to the bispectral analysis monitor, pressing the electrodes firmly to confirm that the automatic test is passed.

Have the anesthesiologist enter the patient's individual age, height, weight, gender, and Propofol plasma target concentration into the data manager with the pre-programmed pharmacokinetic model of Marsh. Now dim the lights in the operating room and use the TCI infusion pump to infuse an initial target plasma level of two micrograms per milliliter of Propofol, inducing sleep. Under continuous monitoring, raise the target plasma Propofol level 0.2 micrograms per milliliter every two minutes.

The most critical step is identifying the target sedation depth. What can be identified as a sleeping patient with closed eyes and spontaneous breathing, accompanied by snoring or an observed obstructive apnea at a target bispectral analysis corridor of 50 to 70. Once the target depth of sedation is reached, stand at the head on the right side of the patient and insert a flexible fiber endoscope transnasally via the inferior nasal meatus.

When the endoscope is in place, using the image acquisition system according to the manufacturers instructions, begin the endoscopic examination of the upper airways by video endoscopy in approximal to distal direction from the nasofarinks as far as the hypopharyngeal entrance. At the target depth of sedation, classify the obstruction sites, obstruction configuration patterns, and degrees of the obstruction severity according to the VOTE system. In the case of isolated sleep endoscopy, after completing the endoscopic examination, stop the Propofol infusion to terminate the patient's sedation.

In the case of sleep endoscopy as part of a planned surgical procedure, have the anesthesiologist start the opioid infusion to induce a total intravenous anaesthesia while increasing the infusion of the Propofol until a loss of consciousness is observed. Then inject a muscle relaxant and intubate the patient prior to beginning the surgical procedure. The identified sites of obstruction are, in decreasing order of frequency, velum, tongue base, oropharynx, and at the level of the epiglottis.

Among the patients with mild obstructive sleep apnea, more than half demonstrate a complete obstruction at a single site, with two or more obstructions sites present in nearly half of the patients. Over half of the patients with moderate obstructive sleep apnea, present a solitary complete obstruction with again, almost half of the patients showing obstruction at two or more sites. Only 20%of patients with sever obstructive sleep apnea exhibit an obstruction at a single site with two or more sites of obstruction observed in 80%of patients with severe obstructive sleep apnea.

48%of the severe obstructive sleep apnea patients display obstruction at the tongue base, which is combined with one other site in 91.7%of cases. The epiglottis is typically the site of at least one obstruction in 52%of cases with 40%of severe obstructive sleep apnea patients also demonstrating coexistent obstructions at the tongue base. The analysis of velum obstruction patterns only reveals a market decrease in anterior posterior collapses from mild and moderate to severe obstructive sleep apnea.

In contrast, a substantial increase of concentric obstructions emerges from mild to moderate to severe obstructive sleep apnea, whereas the ratio of partial and complete velum obstruction appears to be independent of obstructive sleep apnea severity. Drug induced sleep endoscopy provides further insights into the pathophysiology of obstructive sleep apnea and may improve individualized surgical treatment. Whereas investigations in awake patients frequently underestimate the obstruction patterns, particularly at the level of the tongue base and epiglottis.

Once mastered, this procedure can be completed in ten to fifty minutes. Using microchip controlled syringe pumps and pharmacokinetics models, target controlled infusion is a patient individualized drug application method suitable to gradually achieve and maintain certain degrees of sedation by producing and sustaining constant plasma levels of a sedative. Bispectral analysis, which provides a dimensionless number between zero and one hundred, independent of an examiner's interpretation, is currently the best clinically evaluated and easily obtainable parameter for charting sedation depth.

The multilevel obstruction is present in 80%of cases of sever obstructive sleep apnea, with over half of the cases demonstrating epiglottic movement and illustrating the need for the pre-interventional sleep endoscopy. After watching this video, you should have a good understanding of how to preform a standardized and reproducible drug induced sleep endoscopy for the differentiation of individual obstruction patterns in heterogeneous groups of patients with obstructive sleep apnea.