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

Kus LH, Sklar MC, Negandhi J, Estrada M, Eskander A, Harrison RV, Campisi P, Forte V, Propst EJ - J Otolaryngol Head Neck Surg (2013)

Bottom Line: 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.Amongst hypoxic/degenerative features, extravasation was the only feature that was significantly higher in the accelerated subglottic injury group (P=.000).Subglottic 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.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Purpose: Subglottic 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.

Methods: Six 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.

Results: Animals 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).

Conclusions: Subglottic 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.

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Related in: MedlinePlus

Creating a vascular circuit in the head and neck for corrosion casting. (A) Blue casting reagent is retrieved from a reservoir by a cardiac perfusion pump and introduced into the arterial circulation via an aortic cannula. After circulating through the head and neck, the venous effluent is collected via a cannula in the superior vena cava. White arrows indicate direction of fluid flow. (B) A Satinsky clamp (SC1) is placed on the ascending aorta (AA) proximal to the bicarotid trunk (BCT). Another is placed distal to the bicarotid trunk on the descending aorta (not seen). A third Satinsky clamp (SC3) is placed on the superior vena cava (SVC) just proximal to the right atrium (RA). One cannula (C1) is placed in the bicarotid trunk (BCT) and another (C2) is placed in the superior vena cava (SVC). (C) A change in skin colour from pink to blue denotes complete perfusion of casting reagent.
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Figure 1: Creating a vascular circuit in the head and neck for corrosion casting. (A) Blue casting reagent is retrieved from a reservoir by a cardiac perfusion pump and introduced into the arterial circulation via an aortic cannula. After circulating through the head and neck, the venous effluent is collected via a cannula in the superior vena cava. White arrows indicate direction of fluid flow. (B) A Satinsky clamp (SC1) is placed on the ascending aorta (AA) proximal to the bicarotid trunk (BCT). Another is placed distal to the bicarotid trunk on the descending aorta (not seen). A third Satinsky clamp (SC3) is placed on the superior vena cava (SVC) just proximal to the right atrium (RA). One cannula (C1) is placed in the bicarotid trunk (BCT) and another (C2) is placed in the superior vena cava (SVC). (C) A change in skin colour from pink to blue denotes complete perfusion of casting reagent.

Mentions: A 25 cm vertical thoracotomy incision was made in the midline of the chest from sternal notch to xiphoid process using monopolar cautery and Liston bone cutting forceps. The superior vena cava and aortic arch were dissected free from their posterior attachments and the pig was euthanized with an intracardiac injection of Euthanyl (25 mg/kg). The mean duration of surgery was 97.3 +/- 8.9 minutes (range 85–113 minutes). Contrary to humans, whereby the left common carotid artery arises from the aorta and the right common carotid artery arises from the brachiocephalic artery, pigs have a solitary bicarotid trunk that divides distally into both left and right common carotid arteries[9]. Satinsky clamps were placed on the aortic arch proximally and distally to the bi-carotid trunk as well as on the superior vena cava adjacent to the right atrium. This created a vascular circuit from the bi-carotid trunk to the superior vena cava (Figure 1). Purse string sutures were placed in the superior vena cava and the arch of the aorta at the takeoff of the bi-carotid trunk using 5–0 Polypropylene sutures (Ethicon, Somerville, New Jersey). These sites were incised with a scalpel and cannulated with 20 French aortic and venous catheters (Terumo Cardiovascular Systems, Ann Arbor, Michigan), respectively (Figure 1). Choker sleeves were used to tighten the purse string sutures and minimize leakage from the cannulation sites. The aortic cannula was attached to a pediatric cardiac perfusion pump (Medtronic, Minneapolis, Minnesota) using ¼ inch surgical tubing (Saint-Gobain Performance Plastics, Akron, Ohio). One-quarter inch surgical tubing was also attached to the venous cannula and was left open to air to allow the intravascular effluent to drain out. This created a vascular loop through the animal’s head and neck whereby fluid could be injected and recovered (Figure 1). 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 (i.e. venous cannula effluent was clear). Arterial and venous cannulae were clamped and the animals were transported to a ventilated room for casting.


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

Kus LH, Sklar MC, Negandhi J, Estrada M, Eskander A, Harrison RV, Campisi P, Forte V, Propst EJ - J Otolaryngol Head Neck Surg (2013)

Creating a vascular circuit in the head and neck for corrosion casting. (A) Blue casting reagent is retrieved from a reservoir by a cardiac perfusion pump and introduced into the arterial circulation via an aortic cannula. After circulating through the head and neck, the venous effluent is collected via a cannula in the superior vena cava. White arrows indicate direction of fluid flow. (B) A Satinsky clamp (SC1) is placed on the ascending aorta (AA) proximal to the bicarotid trunk (BCT). Another is placed distal to the bicarotid trunk on the descending aorta (not seen). A third Satinsky clamp (SC3) is placed on the superior vena cava (SVC) just proximal to the right atrium (RA). One cannula (C1) is placed in the bicarotid trunk (BCT) and another (C2) is placed in the superior vena cava (SVC). (C) A change in skin colour from pink to blue denotes complete perfusion of casting reagent.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3815236&req=5

Figure 1: Creating a vascular circuit in the head and neck for corrosion casting. (A) Blue casting reagent is retrieved from a reservoir by a cardiac perfusion pump and introduced into the arterial circulation via an aortic cannula. After circulating through the head and neck, the venous effluent is collected via a cannula in the superior vena cava. White arrows indicate direction of fluid flow. (B) A Satinsky clamp (SC1) is placed on the ascending aorta (AA) proximal to the bicarotid trunk (BCT). Another is placed distal to the bicarotid trunk on the descending aorta (not seen). A third Satinsky clamp (SC3) is placed on the superior vena cava (SVC) just proximal to the right atrium (RA). One cannula (C1) is placed in the bicarotid trunk (BCT) and another (C2) is placed in the superior vena cava (SVC). (C) A change in skin colour from pink to blue denotes complete perfusion of casting reagent.
Mentions: A 25 cm vertical thoracotomy incision was made in the midline of the chest from sternal notch to xiphoid process using monopolar cautery and Liston bone cutting forceps. The superior vena cava and aortic arch were dissected free from their posterior attachments and the pig was euthanized with an intracardiac injection of Euthanyl (25 mg/kg). The mean duration of surgery was 97.3 +/- 8.9 minutes (range 85–113 minutes). Contrary to humans, whereby the left common carotid artery arises from the aorta and the right common carotid artery arises from the brachiocephalic artery, pigs have a solitary bicarotid trunk that divides distally into both left and right common carotid arteries[9]. Satinsky clamps were placed on the aortic arch proximally and distally to the bi-carotid trunk as well as on the superior vena cava adjacent to the right atrium. This created a vascular circuit from the bi-carotid trunk to the superior vena cava (Figure 1). Purse string sutures were placed in the superior vena cava and the arch of the aorta at the takeoff of the bi-carotid trunk using 5–0 Polypropylene sutures (Ethicon, Somerville, New Jersey). These sites were incised with a scalpel and cannulated with 20 French aortic and venous catheters (Terumo Cardiovascular Systems, Ann Arbor, Michigan), respectively (Figure 1). Choker sleeves were used to tighten the purse string sutures and minimize leakage from the cannulation sites. The aortic cannula was attached to a pediatric cardiac perfusion pump (Medtronic, Minneapolis, Minnesota) using ¼ inch surgical tubing (Saint-Gobain Performance Plastics, Akron, Ohio). One-quarter inch surgical tubing was also attached to the venous cannula and was left open to air to allow the intravascular effluent to drain out. This created a vascular loop through the animal’s head and neck whereby fluid could be injected and recovered (Figure 1). 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 (i.e. venous cannula effluent was clear). Arterial and venous cannulae were clamped and the animals were transported to a ventilated room for casting.

Bottom Line: 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.Amongst hypoxic/degenerative features, extravasation was the only feature that was significantly higher in the accelerated subglottic injury group (P=.000).Subglottic 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.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Purpose: Subglottic 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.

Methods: Six 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.

Results: Animals 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).

Conclusions: Subglottic 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.

Show MeSH
Related in: MedlinePlus