Diode laser spectroscopy for noninvasive monitoring of oxygen in the lungs of newborn infants

Self Cite

There is a need to further improve the clinical care of our most vulnerable patients-preterm infants. Novel diagnostic and treatment tools facilitate such advances. Here, we evaluate a potential percutaneous optical monitoring tool to assess the oxygen and water vapor content in the lungs of preterm babies. The aim is to prepare for further clinical studies by gaining a detailed understanding of how the measured light intensity and gas absorption signal behave for different possible geometries of light delivery and receiver. Such an experimental evaluation is conducted for the first time utilizing a specially developed 3-dimensional-printed optical phantom based on a geometry model obtained from computer tomography images of the thorax (chest) of a 1700-g premature infant. The measurements yield reliable signals for source-detector distances up to about 50 mm, with stronger gas absorption signals at long separations and positions related to the lower part of the lung, consistent with a larger relative volume of this. The limitations of this study include the omission of scattering tissue within the lungs and that similar optical properties are used for the wavelengths employed for the 2 gases, yielding no indication on the optimal wavelength pair to use.

Section: Resultsmentioning

confidence: 70%

Section: Introductionmentioning

confidence: 95%

Development of a 3‐dimensional tissue lung phantom of a preterm infant for optical measurements of oxygen—Laser‐detector position considerations

Larsson

Liao

Lundin

et al. 2017

Self Cite

“…The GASMAS technique, which is reviewed in Ref. , has the ability to detect and characterize free gas, and the method has subsequently been applied to investigations of the sinus cavities , neonatal lungs and the femoral head . It has the potential to non‐invasively measure the concentration of oxygen also behind the eardrum, where oxygen relates to ventilation and possibly to bacterial/viral origin of infection.…”

Section: Introductionmentioning

confidence: 99%

Towards an optical diagnostic system for otitis media using a combination of otoscopy and spectroscopy

Lin

et al. 2019

Self Cite

An improved method, where conventional otoscope investigation of human suspicious otitis media is combined with diffuse reflectance spectroscopy and gas in scattering media absorption spectroscopy (GASMAS) is being developed. Otitis media is one of the most common infectious diseases in children, whose Eustachian tube connecting the middle ear with the nasal cavity is more horizontal than for adults, which leads to impaired fluid drainage. At present, the use of an otoscope to visually observe possible changes in the tympanic membrane appearance is the main diagnostics method for otitis media. Inaccurate diagnosis related to similar symptoms, and the difficulty for small children to describe the condition experienced, frequently leads to over‐prescription of antibiotics and alarming increase in bacterial resistance development. More accurate diagnostic methods are highly desirable. Diffuse reflectance spectroscopy is a non‐invasive quantitative spectroscopic technique that enables to objectively quantify changes in the hemoglobin content of the tympanic membrane related to inflammation. If an infection is present, the ventilatory function of the Eustachian tube is frequently impaired and the middle‐ear cavity will be filled with fluid. GASMAS, a non‐invasive detection method, can non‐invasively determine if gas is replaced by fluid in the middle‐ear cavity.

“…This was followed by a minor study on three healthy, full‐term infants, where it was possible to obtain water vapor gas signal from the lungs . A slightly larger study on 29 healthy, full‐term infants was later performed, where also oxygen was detectable . However, the signal was weak, and quantification of the oxygen concentration was not feasible.…”

Section: Introductionmentioning

confidence: 99%

“…In the previously performed studies a few light injection and detection positions have been investigated. It has been found, as expected, that the positioning of the probes is very important.…”

Section: Introductionmentioning

confidence: 99%

Computer simulation analysis of source‐detector position for percutaneously measured O₂‐gas signal in a three‐dimensional preterm infant lung

Liao

Larsson

Svanberg

et al. 2018

Self Cite

Further improvements in the clinical care of our most vulnerable patients-preterm infants-are needed. Novel diagnostic and surveillance tools facilitate such advances. The GASMAS technique has shown potential to become a tool to, noninvasively, monitor gas in the lungs of preterm infants, by placing a laser source and a detector on the chest wall skin. It is believed that this technology will become a valuable clinical diagnostic tool for monitoring the lung function of these patients. Today, the technology is, for this application, in an early stage and further investigations are needed. In the present study, a three-dimensional computer model of the thorax of an infant is constructed, from a set of CT images. Light transport simulations are performed to provide information about the position dependence of the laser- and detector probe on the thorax of the infant. The result of the simulations, based on the study method and the specified model used in this work, indicates that measurement geometries in front and on the side of the lung are favorable in order to obtain a good gas absorption signal.