Detection of acute smoke-induced airway injury in a New Zealand white rabbit model using optical coherence tomography

Abstract

Optical coherence tomography (OCT) is a micron scale high-resolution optical technology that can provide real-time in vivo images noninvasively. The ability to detect airway mucosal and submucosal injury rapidly will be valuable for a range of pulmonary applications including assessment of acute inhalation smoke and burn injury. OCT has the potential ability to monitor the progression of airway injury changes including edema, hyperemia, and swelling, which are critical clinical components of smoke-inhalation injury. New Zealand white male rabbits exposed to cold smoke from standardized unbleached burned cotton administered during ventilation were monitored for 6 h using a 1.8-mm diameter flexible fiberoptic longitudinal probe that was inserted through the endotracheal tube. The thickness of the epithelial, mucosal, and submucosal layers of the rabbit trachea to the tracheal cartilage was measured using a prototype superluminescent diode OCT system we constructed. OCT was able to detect significant smoke-injury-induced increases in the thickness of the tracheal walls of the rabbit beginning very shortly after smoke administration. Airway wall thickness increased to an average of 120% (+/-33%) of baseline values by 5 h following exposure. OCT is capable of providing real-time, noninvasive images of airway injury changes following smoke exposure. These studies suggest that OCT may have the ability to provide information on potential early indicators of impending smoke-inhalation-induced airway compromise.

In vivo optical coherence tomography detection of differences in regional large airway smoke inhalation induced injury in a rabbit model

“…General model and preparation methods have been described previously 30 and are briefly summarized here.…”

“…On completion of the experiment, the animals were euthanized with an intravenous injection of Eutha-6 (1.0-2.0 cc) administered through the marginal ear vein. 30 …”

“…30 70 g of unbleached cotton was burned in a modified bee smoker (Smoke Stack Smoker 644, Brushy Mountain Bee Farm, Moravian Falls, North California) for approximately 20 min. The bee smoker was then connected to the inlet port of the mechanical ventilator with the tidal volume and ventilation rate set at 700 ml and 25 breaths per minute, respectively.…”

“…High-resolution flexible fiber optic optical coherence tomography (OCT) provides the potential to observe real-time changes in the airway mucosa and epithelium using minimally invasive imaging techniques. [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] Most importantly, some of the early pathologic changes following smoke inhalation that may be indicative of the extent of injury such as edema and hyperemia 2,[26][27][28][29] may not be apparent clinically, endoscopically, or following histologic preparations of excised specimens, but can be readily detected on OCT. 30 Previous OCT airway injury studies 30 in rabbit smoke inhalation models suggested to us that the upper trachea airway may react very differently to acute smoke inhalation compared to distal trachea and proximal bronchi. The purpose of this study was to demonstrate the potential role of OCT in quantitatively detecting early smoke inhalation injury and assessing differences in response of more proximal versus distal large airways to smoke inhalation injury.…”

Optical imaging of subacute airway remodeling and adipose stem cell engraftment after airway injury

“…Optical coherence tomography (OCT) is a recently developed technology capable of providing real-time, noninvasive, high-resolution (micron-level) imaging of tissues such as trachea and bronchi to depths up to 2 mm below the tissue surface. To date, there have been multiple studies using OCT to detect acute airway inflammation and chronic subglottic stenosis in rabbit models [6,7]. Recently, with respect to early intervention, adipose stem cells have been studied as a potential alternative solution to ameliorate airway or lung injury.…”