Airway stenosis

Furthermore, pH determination has been used in other clinical research, both alone and in combination with other measurements. This research includes studies into the relationship between extracellular and intracellular pH in an ischemic heart [6, 7], the pH of airway lining fluid in respiratory disease [8], the study of pH as a marker for pyloric stenosis [9], malnutrition in alkalotic peritoneal dialysis patients [10], pH modulation of heterosexual HIV transmission [11, 12], and wound prevention and treatment [13], In addition, pH changes due to blood acidosis have been used to trigger and pace the ventricular rate of an implanted cardiac pacemaker [14], Research using pH measurements... 

This curve is seen where a large airway has a fixed orifice through which gas is able to flow, such as may be seen in patients with tracheal stenosis. The peak inspiratory and expiratory flow rates are, therefore, dependent on the diameter of the orifice rather than effort. The curves should be drawn almost symmetrical as above, with both limbs demonstrating markedly reduced flow. The TLC and RV are generally unaffected. 

Angioedema due to ACE inhibitors can manifest as recurrent episodes of facial swelling, which resolves on withdrawal, or as acute oropharyngeal edema and airways obstruction, which requires emergency treatment with an antihistamine and corticosteroids. It may be life-threatening (75) and may need tracheostomy (76). It is occasionally fatal (77). An unusual presentation with subglottic stenosis has also been reported (78). A variant form is angioedema of the intestine, which tends to occur within the first 24 8 hours of treatment (79,80). 

The role of neuronal NOS in the airways is incompletely understood. The gene encoding the enzymes has been isolated and cloned (Bredt et al., 1991), and a strain of neuronal NOS knockout mice has recently been developed (Huang etal., 1993 O Dell etal., 1994). WhUe these mice had pyloric stenosis (a characteristic that reaffirmed the important role of iNOS in gastrointestinal neurotransmission), they had no obvious abnormalities of airway structure. The relevance of these findings to the human airway remains to be determined, and the data need to be considered in light of the diverse bioactivities of NO in the lung. 

Snashall, P.D. and Chung, K.F. (1991). Airway obstruction and bronchial hyperresponsiveness in left ventricular failure and mitral stenosis. Am. Rev. Respir. Dis. 144, 945-956. 

Acute, heavy exposure to SM causes loss of the columnar cells of the upper respiratory tract, peribronchial edema, hyperemia of the blood vessels, cellular infiltrations in the submucosa, and intense vacuolization and disorganization of the cytoplasmic and nuclear structures (Emad and Rezaian, 1997, 1999). Pulmonary hemorrhage, pulmonary edema, and respiratory failure similar to ARDS may also occur. These cytotoxic effects are associated with acute thermal injury sustained by the airway mucosa and lead to scarring and development of stenosis of the tracheobronchial tree as was observed in 9.64% of the SM-exposed patients. 

Sondrup C, Liu Y, Shu X Z, Prestwich G D and Smith M E (2006), Cross-linked hyaluronan-coated stents in the prevention of airway stenosis , Otolaryngol Head... 

Hoppe H, Thoeny HC, Dinkel HP, Zbaren P, Vock P (2002) Virtual laryngoscopy and multiplanar reformats with multirow detector CT for detection and grading of upper airway stenosis. Rofo 174 1003-1008 Jolesz FA, Lorensen WE, Shinmoto H et al (1997) Interactive virtual endoscopy. AJR Am J Roentgenol 169 1229-1235 Joshi AR, Khanna PC, Merchant SA, Khandelwal A, Agrawal N, Karnik ND (2003) Role of multidetector CT virtual bronchoscopy in the evaluation of post-tracheostomy tracheal stenosis - a preliminary study. J Assoc Physicians India 51 871-876... 

The most important morphological examination prior to insertion of an airway stent is a spiral computed tomography (CT) of the major airways. A CT enables a delineation of the airway obstruction. It further demonstrates the length of stenosis, grade of obstruction, and allows calibrated measurements of the smallest diameter of the obstruction. CT can also differentiate a mucosal obstruction from a submucosal cause of obstruction, and further extra-tracheal or exo-bronchial disease responsible for airway comprise. Another advantage of CT is the possibility to assess the relation of the underlying cause of obstruction to other crucial mediastinal and/or pulmonary structures (e.g., major vessels, esophagus, heart, lymph nodes). 

George and colleagues (1992) treated nine patients with malignant central airway obstruction due to tracheal (n=3) or main bronchial ( =6) stenosis with Gianturco stents. All patients suffered from severe dyspnea or asphyxia (four were emergency treatments). All patients had dramatic and rapid reUef of their symptoms after stent insertion. Two patients with intraluminal tumor growth required additional endobronchial measures to control local tumor progression. Patients survived between 3 weeks and 8 months after the intervention. Causes of death were cachexia or pneumonia. 

Bolliger CT, Heitz M, Hauser R, Probst R, Perruchoud AP (1996) An airway Wallstent for the treatment of tracheobronchial malignancies. Thorax 51 1127-1129 Bolliger CT, Wyser C, Wu X et al. (1999) Evaluation of a new self-expandable silicone stent in an experimental tracheal stenosis. Chest 115 496-501... 

Tanigawa N, Sawada S, Okuda Y, Kobayashi M, Mishima K (2000) Symptomatic improvement in dyspnea following tracheobronchial metallic stenting for malignant airway obstruction. Acta Radiol 41 425-428 Tojo T, lioka S, Kitamura S, Maeda M, Otsuji H, Uchida H, Mori T, Furuse K (1996) Management of malignant tracheobronchial stenosis with metal stents and Dumon stents. Ann Thorac Surg 61 1074-1078... 

Respiratory diseases are considered among the main causes of mortality worldwide, especially in children and in adult elderly. More than 40 pathological conditions affecting the airways have been identified, including congenital birth defects, cancer, trauma, infections, and stenosis [1],... 

Regarding Y-shaped tubular scaffolds, a limited experimentation has been conducted. Sekine et al. [ 130] implanted a Y-shaped Marlex mesh tube in dogs. The tubes were reinforced with polypropylene spiral and coated with collagen from porcine skin. Six of the 20 dogs have survived after experimentation. The main causes of death were obstmction of the main bronchus, omental necrosis, and air leakage. The same prosthesis was grafted as tracheobronchial bifiircalion replacement after 5 years, the scaffold was completely incorporated. Neitho- stenosis nor dehiscence was observed, and a functional airway was revealed [131]. 

When sarcoidosis progresses to fibrosis, architectural distortion and traction bronchiectasis classically radiating from the hilum to the adjacent upper and lower lobes can be found. Other common CT abnor-mahties in fibrotic sarcoidosis include honeycombing, cysts, and buUa formation. Airway stenosis in sarcoidosis is usually due to extrinsic scarring, or to endobronchial granulomas, whereas lymphadenopathy alone is a rare cause of symptomatic airway narrowing. 

Multislice CT is the method of choice for the morphological visualization of the airways and the associated diseases. High isotropic resolution and high contrast are the ideal prerequisites to generate MPRs in order to demonstrate the typical findings of airway disease, such as dilation, ectasis, wall thickening, increased collapsibility, and stenosis as well as visibility of small airways in bronchiolitis. The major diseases of the airways that can be adequately studied by multislice CT are tracheobronchomalacia, chronic obstructive pulmonary disease (COPD), and cystic fibrosis (CF). 

Quint LE, Whyte RI, Kazerooni EA, et al. Stenosis of the central airways evaluation by using helical CT with multiplanar reconstructions. Radiology 1995 194 (3) 871-877. 

Obstructive lung disease has been rarely associated with BD as well as trachea-bronchial ulcerations and stenosis. Ulcerative lesions may be found in the trachea and proximal airways. Mucosal edema may result in irregular narrowing of the airway (21-23). 

Imbalance between work of breathing and respiratory muscle capacity Critical illness polyneuropathy or myopathy Upper airway obstraction (e.g., tracheal stenosis)... 

---