Tracheal Clearance Research Articles

The Prevalence and Risk Factors of Tracheostomal Stenosis Following Total Laryngectomy

Background: Tracheostomal stenosis (TS) following total laryngectomy is relatively common in patientsand a distressing complication with major effects on patient rehabilitation it affected 4-44% of patientsfollowing total laryngectomy worldwide. Various etiological factors and some risks have been indicated ascontributing to the onset of stenosis.Purpose: We aimed to investigate the prevalence and risk factors of tracheostomy stenosis following totallaryngectomyMethod: Tracheostomal stenosis was defined as respiratory insufficiency at rest or during exercise, difficultyin tracheal clearance due to non laminar flow, or both. Eighty data of patients were enrolled in this studyconsisting of 76 male (95.0%) and 4 females (5.0%). Baseline characteristics (BL) stage of cancer (SC), typeof surgery (TS), the onset of stenosis following surgery (OS) and risk factors (RF) from each patient wererecorded and analyzed using a pre-installed statistic software.Result: The overall prevalence of tracheostomal stenosis was 13.8% (11 of 80 patients). The prevalence andrisk factors of tracheostomal stenosis following total laryngectomy consisted of 7 hypertrophic scar patients(63.3%), 2 infection patients (18.12), and 1 radiotherapy and peristomal fat patient (9.01), respectively.Conclusion: Out of eighty patients, eleven patients indicates the characters of tracheostomal stenosisusing the bevel technique. The most common etiological factor is hypertrophic scar, followed by infection,radiotherapy and peristomal fat.

Mucociliary clearance. Results in smokers, nonsmokers and patients with with respiratory tract diseases

Using the modified radiographic teflon particle method the tracheal mucociliary clearance velocity (TCV) was found to be 13.5 +/- 4.5 mm/min in 36 normal probands. In 18 "normal" smokers there was a statistically slightly significant diminution when compared with 18 age-matched non-smokers (12.1 +/- 5.7 vs 15.0 +/- 4.2 mm/min; P less than 0.1). Some smokers with values below 7 mm/min could be "potential chronic bronchitis". Acute exposure to cigarette smoke led to a decrease of TCV from 19 to 8 in healthy smokers, and from 20 to 5 mm/min in nonsmokers. Whereas TCV was equally diminished to values between 0 and 5 mm/min in chronic bronchitis (n = 42), bronchial carcinoma (n = 8) and advanced bronchial asthma (n = 8), patients with bronchiectasis (n = 8) showed marked negative tracheal clearance of up to -25 mm/min.

Acute exposure to acid fog. Effects on mucociliary clearance.

Submicrometric sulfuric acid (H2SO4) aerosol can affect mucociliary clearance without eliciting irritative symptoms or changes in pulmonary function. The effect of larger fog droplets containing H2SO4 on mucociliary clearance is unknown. We quantified mucociliary clearance from the trachea (n = 4) and small airways (n = 7) of young healthy male adults after an acute exposure to H2SO4 fog (MMAD = 10.3 microns; pH = 2.0; liquid water content = 481 +/- 65 mg/m3; osmolarity = 30 mOsm). Acid fog (AF) or saline fog (SF) (10.9 microns; 492 +/- 116 mg/m3; 30 mOsm) was administered for 40 min of unencumbered breathing (no mouth-piece) at rest and for 20 min of exercise sufficient to produce oronasal breathing. Fog exposures were followed by a methacholine (MCh) challenge (a measure of airway reactivity) or inhalation of technetium-99M radioaerosol (MMAD = 3.4 microns) on 2 study days each. Changes in symptoms and forced ventilatory function were also assessed. Clearance was quantified from computer-assisted analyses of gamma camera images of the lower respiratory tract in terms of %removal/min of the radiolabel from the trachea 25 min after inhalation and from the outer zone of the right lung after 1.9 to 3 h. Symptoms, forced ventilatory function, and MCh response were unaffected by either fog. Tracheal clearance was more rapid in four of four subjects after AF (0.83 +/- 1.58% removal/min) compared with that after SF (-0.54 +/- 0.85% removal/min). Outer zone clearance was more rapid in six of seven subjects after AF (0.22 +/- 0.15% removal/min) compared with that after SF (0.01 +/- 0.09% removal/min).(ABSTRACT TRUNCATED AT 250 WORDS)

Respiratory tract clearance of 14C-labeled diesel exhaust compounds associated with diesel particles or as a particle-free extract

Radiolabeled diesel exhaust particles or dichloromethane extracts of these particles were intratracheally instilled (10 mg) into Fischer-344 rats and the clearance of 14C radioactivity was measured. Approximately 88% of the 14C radioactivity associated with the particles was soluble in dichloromethane. The clearance of 14C radioactivity from lungs occurred in two phases. The initial, more rapid phase of lung clearance of both particle-associated 14C radioactivity (Particle 14C) and extract-associated 14C radioactivity (Extract 14C) was very similar ( t 1 2 ⋍ 3 hr ). However, the second phase of lung clearance of the remaining Particle 14C was much slower ( t 1 2 ⋍ 25 days ) than the second phase of lung clearance of the Extract 14C ( t 1 2 ⋍ 2.9 days ). Tracheal clearance rates of 14C radioactivity from both instillation studies were both rapid and similar ( t 1 2 ⋍ 10–12 hr ). These results indicate that diesel engine exhaust particles reduce the lung clearance rate of the organic compounds associated with these particles. These studies also point to the possibility that the rate limiting step in the lung clearance of organic compounds associated with inhaled diesel exhaust particles may be the rate at which they dissociate from these particles in vivo. This is because the long-term clearance rate of the particle-associated organic compounds was shown here to be much slower than that of the same organic compounds in a particle-free form but not as slow as the lung clearance rate reported for diesel exhaust core particles (T. L. Chan, P. S. Lee, W. E. Hering, J. Appl. Toxicol. 1, 77–82 (1981)). These findings will be useful in estimating the lung dose of organic compounds following inhalation of diesel exhaust soot.

Respiratory Tract Clearance of 14C-Labeled Diesel Exhaust Compounds Associated with Diesel Particles or as a Particle-Free Extract

Respiratory Tract Clearance of 14C-Labeled Diesel Exhaust Compounds Associated with Diesel Particles or as a Particle-Free Extract. SUN, J. D., AND MCCLELLAN, R. O. (1984). Fundam. Appl. Toxicol. 4, 388–393. Radiolabeled diesel exhaust particles or dichloromethane extracts of these particles were intratracheally instilled (10 mg) into Fischer-344 rats and the clearance of 14C radioactivity was measured. Approximately 88% of the 14C radioactivity associated with the particles was soluble in dichloromethane. The clearance of 14C radioactivity from lungs occurred in two phases. The initial, more rapid phase of lung clearance of both particle-associated 14C radioactivity (Particle 14C) and extract-associated 14C radioactivity (Extract 14C) was very similar (t½ ⋍ 3 hr). However, the second phase of lung clearance of the remaining Particle 14C was much slower (t½ ⋍ 25 days) than the second phase of lung clearance of the Extract 14C (t½ ⋍; 2.9 days). Tracheal clearance rates of 14C radioactivity from both instillation studies were both rapid and similar (t½ ⋍ 10–12 hr). These results indicate that diesel engine exhaust particles reduce the lung clearance rate of the organic compounds associated with these particles. These studies also point to the possibility that the rate limiting step in the lung clearance of organic compounds associated with inhaled diesel exhaust particles may be the rate at which they dissociate from these particles in vivo. This is because the long-term clearance rate of the particle-associated organic compounds was shown here to be much slower than that of the same organic compounds in a particle-free form but not as slow as the lung clearance rate reported for diesel exhaust core particles (T. L. Chan, P. S. Lee, W. E. Hering, J. Appl. Toxicol. 1, 77–82 (1981)). These findings will be useful in estimating the lung dose of organic compounds following inhalation of diesel exhaust soot.

Deposition, retention, and biological fate of inhaled benzo( a)pyrene adsorbed onto ultrafine particles and as a pure aerosol

The effect of ultrafine, airborne, carrier particles on the deposition, retention, and biological fate of inhaled polycyclic aromatic hydrocarbons (PAHs) was studied. Using a radiolabeled model PAH, [ 3H]benzo( a)pyrene ([ 3H]BaP), Fischer-344 rats were exposed by nose-only inhalation (30 min) to this compound, as a coating (15% by mass) on insoluble 67Ga 2O 3 particles or as a pure aerosol. These aerosols were produced by vapor condensation methods in a dynamic aerosol generation system. The concentrations of [ 3H]BaP in the coated and homogeneous aerosols were 0.6 and 1.0 μg/liter of air, respectively, while the mass median diameter of both these aerosols was approximately 0.1 μm. Pulmonary retention of 3H radioactivity was longer in animals exposed to the [ 3H]BaP coated on the 67Ga 2O 3 particles. The time required to clear 90% of the initial lung burden of 67Ga 2O 3-associated 3H radioactivity detected 30 min postexposure was approximately 1 day as compared to 4 hr for animals exposed to the pure [ 3H]BaP aerosol. Tracheal clearance of 90% of the 67Ga 2O 3-associated 3H radioactivity (as a fraction of the amount detected 30 min postexposure) required 1 day, while only 1.5 hr were required to clear the same percentage of 3H radioactivity from the tracheas of rats exposed to the pure [ 3H]BaP aerosol. The rates of clearance of this 3H material to other tissues suggested that a substantial amount of the [ 3H]BaP coated on 67Ga 2O 3 was cleared from lungs by mucociliary clearance and subsequent ingestion, whereas the majority of the pure [ 3H]BaP aerosol was cleared by direct absorption into blood. In both cases, the ultimate fate of the majority of the [ 3H]BaP and its metabolites was excretion in feces. However, clearance of the 67Ga 2O 3-associated [ 3H]BaP by ingestion may have been the cause for the higher levels and longer retention times of 3H radioactivity in stomach, liver, and kidneys when compared to the levels found in these same tissues from animals exposed to the pure [ 3H]BaP aerosol. Thus, particle association of BaP not only increased the respiratory tract retention of this PAH, but also increased the dose of this compound and its metabolites to stomach, liver, and kidneys.