A presentation by Emilie Krite Svanberg at the 2017 meeting of the Scandinavian Society of Anaestesiology and Intensive Care Medicine. All available content from SSAI2017: https://scanfoam.org/ssai2017/ Delivered in collaboration between scanFOAM, SSAI & SFAI.

1. Emilie Krite Svanberg
MD, PhD
Anesthesiology and Intensive Care Medicine
Skåne University Hospital
Lund/Malmö
No conflict of interest

2. Think of it as pulse oximetry
but for the oxygen gas in the lungs!

3. Spectroscopic Fingerprint!

4. T = I/I0 = e-σ(λ)cl
Tissue
Path length (ɭ)
Clear solution
Path length (ɭ)
[c]
[c]
[c]
[c]
[c]
II0
I0
I T = transmitted light
I = light intensity at the absorption line
I0 = intensity of emitted light
σ(λ) = extinction coefficient
c = concentration
l= path length through the sample
Substance-specific absorption
Beer-Lambert law
I0
I
ɭ
[c]
?

5. Hb-
HbO2
Melanin
Lipid
Water
O2
H2O
vapor
O2 H2O
σ(λ)

6. Free oxygen
Possibilities of monitoring the oxygen content in the lungs

7. – 50-90 % av preterm infants
(v 22-31)
– Lack of surfactant
– Immature lungs
– Inhomogenous air distribution
– Permanent lung and brain
damage
X-ray…
Can the use be reduced?

8. • GAs in Scattering Media Absorption Spectroscopy
(GASMAS)
• Possibility to measure and quantify gas enclosed in
biological tissue cavities
• Non-invasive optical technique
• Near infra-red light (tissue optical window)
• Determination of the oxygen
concentration by normalization
against known water vapor concentration
• Estimation of the cavity size

9. λ
Power
σ[a.u]
Tunable diode laser absorption spectroscopy (TDLAS)Sharp absorption lines...

10. The amplitude of the curve is proportional to the absorption of oxygen gas or water vapor
…but very weak.
Second derivative of the signal

11. • To develop a new non-invasive
surveillance technique for monitoring
of lung function in newborn/preterm
infants

12. • 3 full-term infants (~ 4 kg)
H2O Lung
Lundin P, Krite Svanberg E. et al.

13. • 29 healthy full-term infants (0-3 days old)
• GASMAS further developed
- stronger O2 laser
• Lung measurements
• Approx. 10 sec/measurement
• Total time 20 min/infant
Krite Svanberg E. et al. Pediatric Research (2016), 79, 621-628;
doi: 10.1038/pr.2015.267

14. SNR = 11 SNR = 12
SNR = 3.1 SNR = 0.9
a)
d)c)
b)

15. • Strong and clear oxygen signals over the
lungs!
• Measurements possible up to 4 kg
• Potential for an ”optical stetoscope”
• Possibly minimizing the need of potentially
harmful investigations
• Probes too large for measurements on
preterm infants

16. • The most important future goal with gas monitoring in the lungs
is to be able to reduce potentially harmful x-ray radiation
• Increase the output of the laser for better signal quality
• Choose a wavelength for H2O closer to O2
• Internal light illumination from the airways
 European Eurostar project
 Patent application (internal laser illumination)

20. J Biophotonics. 2017 Aug 16. doi: 10.1002/jbio.201700097. [Epub ahead of print]
Development of a 3D tissue lung phantom of a preterm infant for optical measurements of oxygen - laser-detector
position considerations.
Larsson J1, Liao P2,3, Lundin P2,3, Krite Svanberg E4,5, Swartling J3, Lewander Xu M3, Bood J1, Andersson-Engels S2,6,7.
Absorption Intensity

21. • Guide respirator settings for infants
• Follow in real-time result of intervention
• Optical stetoscope – lung borders
• Lung measurements on adults
• Possibly minimizing the need of potentially
harmful investigations
• GASMAS could be a valuable complement
for surveillance and treatment evaluation of
preterm infants

22. • Stefan Andersson-Engels
• Lars Björklund
• Joakim Bood
• Lorenzo Cocola
• Vineta Fellman
• John Jahr
• Jim Larsson
• Marcus Larsson
• Märta Lewander Xu
• Peilang Liao
• Patrik Lundin
• Gabriel Somesfalean
• Katarina Svanberg
• Sune Svanberg
• Johannes Swartling
• Jonas Åkeson

23. Ragnhild 2