Suitability of the JAWAC Sensor to Complement CO₂ Monitoring to Detect Obstructive Apnea during Propofol TCI Sedation

Background: Induced obstructive apnea still occur during propofol sedation despite CO₂ monitoring. This even leads to episodes of oxygen desaturation. The Jaw activity analysis system ( JAWAC) has become a monitor of reference to detect sleep obstructive apnea (1).

Objective: Our purpose was to analyze the JAWAC and CO₂ (CapnoLine) monitoring signals to define a more reliable and faster recognition sequence for obstructive apnea than CO₂ monitoring alone.

Methods: This study was registered on ClinicalTrial.gov [NCT02909309]. 21 participants scheduled for sleep endoscopy were recruited. SPO₂, CO₂, JAWAC and BIS signals were recorded continuously. Propofol TCI sedation (Marsh pharmacokinetic model) was started at a 2 µg/ml and progressively increased by 1 µgml. Apnea was defined as a zero value lasting 10 seconds on the CapnoLine.

Results: 54 episodes of obstructive apnea were recorded. The combination of the analysis of the JAWAC signal with the respiratory rate from the CapnoLine determined a new recognition sequence. On average, this sequence detects apnea 37 seconds before CapnoLine. Kappa agreement comparing this sequence and the CapnoLine was very good reaching 68%. Sensitivity and specificity of the sequence were 76% and 92.5%, respectively.

Conclusion: Even if CO₂ monitoring is recommended by scientific societies, it does not predict all episodes of obstructive apnea during propofol sedation. The simultaneous use of both JAWAC and CapnoLine sensors seems to provide a more reliable and faster signal to detect obstructive apnea during propofol sedation. This combination should be assessed during different sedation techniques and other procedures.

(1) Martinot, Respirology 2016