Corrosion casting of the subglottis following endotracheal tube intubation injury: A pilot study in Yorkshire piglets

Abstract

PurposeSubglottic stenosis can result from endotracheal tube injury. The mechanism by which this occurs, however, is not well understood. The purpose of this study was to examine the role of angiogenesis, hypoxia and ischemia in subglottic mucosal injury following endotracheal intubation.MethodsSix Yorkshire piglets were randomized to either a control group (N=3, ventilated through laryngeal mask airway for corrosion casting) or accelerated subglottic injury group through intubation and induced hypoxia as per a previously described model (N=3). The vasculature of all animals was injected with liquid methyl methacrylate. After polymerization, the surrounding tissue was corroded with potassium hydroxide. The subglottic region was evaluated using scanning electron microscopy looking for angiogenic and hypoxic or degenerative features and groups were compared using Mann–Whitney tests and Friedman’s 2-way ANOVA.ResultsAnimals in the accelerated subglottic injury group had less overall angiogenic features (P=.002) and more overall hypoxic/degenerative features (P=.000) compared with controls. Amongst angiogenic features, there was decreased budding (P=.000) and a trend toward decreased sprouting (P=.037) in the accelerated subglottic injury group with an increase in intussusception (P=.004), possibly representing early attempts at rapid revascularization. Amongst hypoxic/degenerative features, extravasation was the only feature that was significantly higher in the accelerated subglottic injury group (P=.000).ConclusionsSubglottic injury due to intubation and hypoxia may lead to decreased angiogenesis and increased blood vessel damage resulting in extravasation of fluid and a decreased propensity toward wound healing in this animal model.

Angiogenesis in costal cartilage graft laryngotracheoplasty: A corrosion casting study in piglets

“…They were ventilated through a size 3 pediatric laryngeal mask airway (LMA North America, San Diego, CA) to avoid further injury to the airway. We have previously described this casting technique in detail . Essentially, a 25‐cm midline vertical thoracotomy was performed, the superior vena cava and aortic arch were dissected out, and the pig was euthanized with an intracardiac injection of Euthanyl (25 mg/kg).…”

“…The vascular loop was flushed with 3 L of heparinized (15 units/mL) 0.9% saline at a rate of 150 mL/min until there was no more blood in the circuit. The blue casting reagent (methyl methacrylate) described elsewhere was perfused into the aortic cannula until it extravasated from the venous cannula and the animal's skin color changed from pink to blue . The animal was placed on ice for 3 hours while the casting resin solidified.…”

“…We have previously described this casting technique in detail. 4 Essentially, a 25-cm midline vertical thoracotomy was performed, the superior vena cava and aortic arch were dissected out, and the pig was euthanized with an intracardiac injection of Euthanyl (25 mg/kg). Contrary to humans, pigs have a solitary bicarotid trunk that divides into both left and right common carotid arteries.…”

Post Intubation Tracheal Stenosis in Children

“…The main risk factors associated with tracheal stenosis are, the time spent intubated, tissue hypoperfusion and intubation related trauma. 3 , 4 …”

Unexpected Difficulties in Intubation: Undiagnosed Subglottic Stenosis

“…Anestezistler için oldukça önemli bir sorun olan SGS'nin risk faktörleri arasında, entübasyon süresi, hipoperfüzyon, balonlu endotrakeal tüpler ve entübasyona bağlı travma bulunmaktadır (2,3). Biz de önceden SGS tanısı bilinmeyen, konka hipertrofisi nedeniyle radyofrekans (RF) ve gromet yerleştirilmesi operasyonu sırasında entübasyon güçlüğü yaşadığımız olgumuzdaki tecrübemizi paylaşmayı amaçladık.…”