Photoacoustic detection of propofol in breath gas for monitoring depth of anaesthesia: from bench to bedside

Meidert, Agnes S. ; Rucz, Péter ; Angster, Judit; Esser, Joseph ; Miklós, András und Schelling, Gustav (2025): Photoacoustic detection of propofol in breath gas for monitoring depth of anaesthesia: from bench to bedside. In: British Journal of Anaesthesia, Bd. 135, Nr. 5: S. 1203-1211

Abstract

Background

Ensuring adequate depth of i.v. anaesthesia by measuring propofol in breath gas could increase patient safety. Mass spectrometry, representing the reference standard of propofol breath gas measurements, is not feasible in routine clinical practice; hence, a photoacoustic sensor was developed.

Methods

The photoacoustic sensor quantifies propofol concentration in gas via the sound waves emitted by propofol molecules excited by light of specific wavelength and frequency. We studied the performance of the new sensor in propofol test gas, gas sampling bags filled with breath gas from different patients, and performed real-time measurements in patients undergoing propofol anaesthesia in comparison to ion-molecule reaction mass spectrometry.

Results

In test gas, photoacoustic and mass spectrometry correlated with an R2 of 0.9975 in a range from 2.5 to 60 ppb. In gas sampling bags, propofol could be detected with both methods. Bland–Altman analysis of propofol general anaesthesia over 18 h in 10 patients revealed a mean propofol difference of −0.02 ppb (standard deviation 3.31) between mass spectrometry and photoacoustic measurements in breath gas, ranging from 4 to 47 ppb.

Conclusions

Photoacoustic measurement of propofol concentration in breath gas is feasible with high accuracy in clinical applications.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Medizin > Klinikum der LMU München > Klinik für Anaesthesiologie
• Themengebiete: 600 Technik, Medizin, angewandte Wissenschaften > 610 Medizin und Gesundheit
• ISSN: 00070912
• Sprache: Englisch