2014 / 10 / 21 R2 VS Introduction Drug Drug- -induced sleep - PowerPoint PPT Presentation

2014 / 10 / 21 R2 林書瑜 VS 劉宏濱 主任

Introduction � � Drug Drug- -induced sleep endoscopy (DISE induced sleep endoscopy (DISE ) ) uses sedative-hypnotics to induce moderate obstruction to facilitate anatomic differentiation of obstructive physiolygy. � A diagnostic tool for Obstructive sleep apnea (OSA) � Common collapse sites: palate, pharyngeal wall, tongue base � Real time visual observation of the airway � May also provide prognostic information

Introduction � � Polysomnography Polysomnography: : � Sleep disorder diagnosis � Sleep-related symptom evaluation � Monitors : � Monitors : � Electroencephalogram (EEG) � Electro-oculogram (Eye movement) � Electromyogram (muscle activity) � Electrocardiogram (EKG) � Nasal pressure transducer � Oronasal thermistor (Air flow) � Oxygen Saturation

Introduction � � Polysomnography Polysomnography: :

Introduction � Obstruction commonly, but not always, occurs contemporaneously with loss of consciousness. � � Propofol Propofol : � Reliable prediction of the necessary porpofol dose to � Reliable prediction of the necessary porpofol dose to achieve and maintain obstruction without causing prolonged loss of consciousness or oxygen desaturation is challenging !

Introduction � � Propofol Propofol : : � Manual bolus � Experienced practitioner to obtain consistent results � Target-controlled infusion (TCI) � Target-controlled infusion (TCI) � Not available in North America… � Small serial increments in the target to achieve the desired clinical end point => time-consuming porcess

Introduction � Both Manual and TCI approaches assume that the anesthesiologist can surmise the appropriate target level for each patient. � We have previously demonstrated in simulation a method for producing a continuously increasing probability of loss for producing a continuously increasing probability of loss of consciousness with a simple sequence of infusion rates . � We hypothesized that such an approach, with a hybrid pharma-cokinetic/pharmacodynamic model , would permit reliable and efficient titration of propofol to an end point of visible airway collapse and/or loss of genioglossus tone in a population with severe OSA.

Method � 97 patients were enrolled in a prospective study of transoral robotic resection of the tongue base � The apnea apnea- -hypopnea hypopnea index (AHI) index (AHI) for each patient was recorded from the sleep study was recorded from the sleep study � Defined as cessation of breathing for 10 seconds or more � � The The saturation saturation nadirs nadirs � The lowest oxygen saturation during the night

Method � All patients were screened with DISE with DISE with propofol propofol infusions infusions determined by custom software written in MATLAB � The system uses the Cortínez et al. pharmacokinetic model and the Johnson pharmacodynamic model to determine an and the Johnson pharmacodynamic model to determine an infusion sequence comprised a bolus, initial infusion, secondary infusion, and a time for transition from the initial to secondary infusion using the age and weight of the individual patient.

� PROPOFOL PHARMACOKINETIC MODEL � the model of Cortínez et al � PROPOFOL PHARMACODYNAMICS MODEL � The model of Johnson et al.

Method � Propofol was administered by an anesthesiologist. � No topical anesthesia / No other IV drugs � 2L/min supplemental oxygen � Pulse oximetry � Pulse oximetry � A Baxter AS50 pump: � Initial bolus and infusion rates as determined by the control system

Method � Bronchoscope � Observation of the pharynx was performed for a sufficient period to obtain images of the anatomic site(s) of obstruction. site(s) of obstruction. � Comparison of saturation nadirs saturation nadirs from DISE and polysomnography was performed with both the paired and unpaired Student t test.

Results � Patient characteristics

Results � The median time to obstruction, as determined by the otorhi-nolaryngologist, was 3.8 minutes. � The mean, predicted effect-site concentration of propofol at obstruction was 4.2 ± 1.3 mcg/mL. at obstruction was 4.2 ± 1.3 mcg/mL. � The median saturation nadir during DISE was significantly higher (91.4 ± 5.1% IQR) than that during standard sleep studies ( 81.0% ± 11.2% IQR)

Nadir oxygen saturation: The lowest oxygen saturation during the night

Discussion � DISE with sedation-hypnotics: � Midazolam regimen � Propofol by TCI or manual bolus � In children: dexmedetomidine after sevoflurane � In children: dexmedetomidine after sevoflurane induction has been reported

Discussion � Narrow range of anesthetic depth � Patients with AHI > 30 (severe OHA) � Most present study excluded higher risk p’ts with BMI> 30 kg/m 2 kg/m � Reports of desaturation requiring bag-mask ventilation are not uncommon � Recent study: Manual group: 65 % V.S the TCI group : 5 % � The effective sedation seen in this study with a low rate of desaturation and infrequent need for airway support is an important result !

Discussion � The lowest saturation measured in our study (patients received oxygen at 2 L/min via oral cannula) was 74 %. � The mean oxygen saturation value was significantly higher than the mean during polysomnography and was than the mean during polysomnography and was comparable with that reported by De Vito during TCI infusion.

Discussion � The extent of desaturation in obese patients with OSA is multifactorial . � In addition to obstruction or apnea, loss of functional residual capacity during sleep and the balance of metabolic residual capacity during sleep and the balance of metabolic rate and oxygen delivery under the effects of propofol also play a role.

Discussion � � TCI TCI : � Good reliability but require slow titration � Predicted effect-site concentration 2.0 ~ 4.8 μg/mL to achieve obstruction have been reported with the achieve obstruction have been reported with the Schnider or Marsh propofol models � The predicted effect-site concentration for obstruction we observed ( 4.2 ± ± 1.3 μg/mL ) when using the Cortinez is in a ± ± range of similar magnitude.

Discussion � In one study by De Vito et al. the average time for the procedures : � the TCI group => 15.2 minutes � the manual control group => 6.2 minutes � the manual control group => 6.2 minutes � The mean time to obstruction employing our control system was 3.9 minutes, which is comparable with the manual approach and substantially faster than with TCI control in published studies.

Conclusions � � Propofol Propofol infusion strategy infusion strategy � Require limited experience with propofol dose selection � Produce airway obstruction faster the TCI based system � O desaturation is within clinically acceptable range � O 2 desaturation is within clinically acceptable range

Thanks for your attention !