Numerical investigation of the influence of the source and detector position for optical measurement of lung volume and oxygen content in preterm infants.

There is an urgent need for improved respiratory surveillance of preterm infants. Gas in scattering media absorption spectroscopy (GASMAS) is emerging as a potential clinical cutaneous monitoring tool of lung functions in neonates. A challenge in the clinical translation of GASMAS is to obtain sufficiently high signal-to-noise ratios in the measurements, since the light attenuation is high in human tissue.

Changes in pulmonary oxygen content are detectable with laser absorption spectroscopy: proof of concept in newborn piglets.

Background: Using an optical method based on tunable diode laser absorption spectroscopy, we previously assessed oxygen (O) and water vapor (HO) content in a tissue phantom of the preterm infant lung. Here we applied this method on newborn piglets with induced lung complications.

Methods: Five mechanically ventilated piglets were subjected to stepwise increased and decreased fraction of inspired oxygen (FiO), to atelectasis using a balloon catheter in the right bronchus, and to pneumothorax by injecting air in the pleural cavity.

Comparison of dermal vs internal light administration in human lungs using the TDLAS-GASMAS technique-Phantom studies.

Oxygen and water vapor content, in the lungs of a 3D-printed phantom model based on CT-images of a preterm infant, is evaluated using Tunable Diode Laser Absorption Spectroscopy (TDLAS) in Gas in Scattering Media Absorption Spectroscopy (GASMAS), that is, the TDLAS-GASMAS technique. Oxygen gas is detected through an absorption line near 764 nm and water vapor through an absorption line near 820 nm. A model with a lung containing interior structure is compared to a model with a hollow lung.

Computer simulation analysis of source-detector position for percutaneously measured O -gas signal in a three-dimensional preterm infant lung.

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.

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

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.

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

Background: Newborn infants may have pulmonary disorders with abnormal gas distribution, e.g., respiratory distress syndrome.

Noninvasive monitoring of gas in the lungs and intestines of newborn infants using diode lasers: feasibility study.

Preterm newborn infants have a high morbidity rate. The most frequently affected organs where free gas is involved are the lungs and intestines. In respiratory distress syndrome, both hyperexpanded and atelectatic (collapsed) areas occur, and in necrotizing enterocolitis, intramural gas may appear in the intestine.

Physiological influence of basic perturbations assessed by non-invasive optical techniques in humans.

New non-invasive techniques enabling frequent or continuous assessments of various pathophysiological conditions might be used to improve in-hospital outcome by enabling earlier and more reliable bedside detection of medical deterioration. In this preclinical study, three modern non-invasive optical techniques, laser Doppler imaging (LDI), near-infrared spectroscopy (NIRS), and tissue viability imaging (TVI), were all evaluated with respect to the influence of basic physiological perturbations (including local changes in arm positioning, skin temperature, and regional blood flow conditions) on quasi simultaneously obtained values of skin perfusion, muscle tissue oxygenation (StO₂), and skin blood volume, recorded in eighteen healthy volunteers. Skin perfusion measured by LDI responded prominently to changes in positioning of the arm, whereas muscle StO₂ measured by NIRS did not change significantly.