Continuous negative external pressure (cNEP) reduces respiratory impairment during screening colonoscopy: a pilot study.

BACKGROUND AND STUDY AIMS: Drugs administered during gastrointestinal procedures cause increased collapsibility of the upper airway, which may lead to respiratory impairment. We evaluated the ability of continuous negative external pressure (cNEP) to lessen respiratory impairment during screening colonoscopy. PATIENTS AND METHODS: The initial 24 patients served as controls, while the next 30 received cNEP. cNEP was delivered by a soft silicone collar placed over the anterior neck. The primary endpoint was the frequency of respiratory impairment, defined as either: (i) a decline from baseline of > 4 % in oxygen saturation, or (ii) apnea lasting ≥ 20 seconds. RESULTS: Mean respiratory impairment episodes were 3.50 in the no-cNEP group vs. 1.92 in the cNEP group, a reduction of 45 % (P = 0.022). Apneas ≥ 20 seconds occurred in 74 % of the no-cNEP group and 28 % of the cNEP group (P = 0.002). While 42 % of the no-cNEP group required increased supplemental oxygen, this was true for only 10 % of the cNEP group (P = 0.01). cNEP adverse events were minimal. CONCLUSIONS: During screening colonoscopy, sedation-related respiratory impairment is significantly reduced by cNEP.ClinicalTrials.gov NCT01895062.

Respiratory morbidity in a coffee processing workplace with sentinel obliterative bronchiolitis cases.

RATIONALE: Obliterative bronchiolitis in former coffee workers prompted a cross-sectional study of current workers. Diacetyl and 2,3-pentanedione levels were highest in areas for flavoring and grinding/packaging unflavored coffee. METHODS: We interviewed 75 (88%) workers, measured lung function, and created exposure groups based on work history. We calculated standardized morbidity ratios (SMRs) for symptoms and spirometric abnormalities. We examined health outcomes by exposure groups. RESULTS: SMRs were elevated 1.6-fold for dyspnea and 2.7-fold for obstruction. The exposure group working in both coffee flavoring and grinding/packaging of unflavored coffee areas had significantly lower mean ratio of forced expiratory volume in 1 s to forced vital capacity and percent predicted mid-expiratory flow than workers without such exposure. CONCLUSION: Current workers have occupational lung morbidity associated with high diacetyl and 2,3-pentanedione exposures, which were not limited to flavoring areas.

Airflow obstruction among street vendors who refill cigarette lighters with liquefied petroleum gas.

BACKGROUND: Manual cigarette lighter refilling with butane/propane admixed liquefied petroleum gas (LPG) is a common low-income occupation in India. This practice may cause adverse health effects from LPG exposure among such workers. OBJECTIVE: To assess respiratory status among LPG-exposed workers and non-exposed controls. METHODS: We quantified the exposure and evaluated respiratory symptoms and lung function among 113 LPG refilling workers (aged 41.9±9.9 years) and 79 controls (aged 40.8±7.2 years). We used multiple linear regression analysis to estimate the LPG exposure response within the group of refilling workers, adjusting for age, height and smoking status. RESULTS: Compared to the controls, the LPG-exposed lighter refillers manifested a 190 ml decrement in 1-second forced expiratory volume (FEV1) (2.55±0.4 vs. 2.26±0.3 l) and a 6% decrement in FEV1/forced vital capacity (FVC) (both P < 0.05). We found a significantly negative exposure response among the LPG workers: for FVC and FEV1, 44 ml per ml of reported daily LPG use in refilling (P < 0.05). CONCLUSION: Likely heavy exposure to LPG through manually refilling cigarette lighters is associated with airflow decrements. This adverse effect may be relevant to other occupational groups heavily exposed to volatile hydrocarbons, especially those in marginal employment sectors.

Intratracheal bleomycin causes airway remodeling and airflow obstruction in mice.

In addition to parenchymal fibrosis, fibrotic remodeling of the distal airways has been reported in interstitial lung diseases. Mechanisms of airway wall remodeling, which occurs in a variety of chronic lung diseases, are not well defined and current animal models are limited. The authors quantified airway remodeling in lung sections from subjects with idiopathic pulmonary fibrosis (IPF) and controls. To investigate intratracheal bleomycin as a potential animal model for fibrotic airway remodeling, the authors evaluated lungs from C57BL/6 mice after bleomycin treatment by histologic scoring for fibrosis and peribronchial inflammation, morphometric evaluation of subepithelial connective tissue volume density, TUNEL (terminal deoxynucleotidyl transferase dUTP-mediated nick-end labeling) assay, and immunohistochemistry for transforming growth factor ß1 (TGFß1), TGFß2, and the fibroblast marker S100A4. Lung mechanics were determined at 3 weeks post bleomycin. IPF lungs had small airway remodeling with increased bronchial wall thickness compared to controls. Similarly, bleomycin-treated mice developed dose-dependent airway wall inflammation and fibrosis and greater airflow resistance after high-dose bleomycin. Increased TUNEL(+) bronchial epithelial cells and peribronchial inflammation were noted by 1 week, and expression of TGFß1 and TGFß2 and accumulation of S100A4(+) fibroblasts correlated with airway remodeling in a bleomycin dose-dependent fashion. IPF is characterized by small airway remodeling in addition to parenchymal fibrosis, a pattern also seen with intratracheal bleomycin. Bronchial remodeling from intratracheal bleomycin follows a cascade of events including epithelial cell injury, airway inflammation, profibrotic cytokine expression, fibroblast accumulation, and peribronchial fibrosis. Thus, this model can be utilized to investigate mechanisms of airway remodeling.

Total airway obstruction during local anesthesia in a non-sedated patient with a compromised airway.

PURPOSE: To report a case of complete upper airway obstruction after topicalization with lidocaine in a completely conscious patient with partial upper airway obstruction. CLINICAL FEATURES: A 69-yr-old man with a history of neck cancer and radiation presented for resection of recurrent neck tumour. No preoperative sedation was given. He had inspiratory and expiratory stridor but had no history of aspiration or swallowing problem. Phonation was distorted but effective. The surgeon was reluctant to perform an awake tracheostomy under local anesthesia. In preparation for a fibrescope-assisted orotracheal intubation, the non-sedated patient was given topical upper airway lidocaine during which he developed total airway obstruction and hypoxemia. He was immediately intubated with a fibrescope. His vocal cords were not edematous although the supraglottic structures appeared to be. The vocal cords were abducted and their movement was limited and not paradoxical. Tumour resection was uneventful upon successful tracheal intubation and general anesthesia. Tracheostomy at the end of the case was difficult, as expected. The patient tolerated the procedures and regained consciousness with no neurologic sequelae. CONCLUSION: Dynamic airflow limitation associated with local anesthesia of the upper airway may lead to complete upper airway obstruction in a compromised airway. The main cause may be the loss of upper airway muscle tone, exacerbated by deep inspiration during panic.

Para-Bromophenacyl bromide alleviates airway hyperresponsiveness and modulates cytokines, IgE and eosinophil levels in ovalbumin-sensitized and -challenged mice.

Airway hyperresponsiveness, airway eosinophilia and increased IgE levels in serum are the important characteristic features of asthma. We evaluated the potential of para-Bromophenacyl bromide (PBPB), a known phospholipase A(2) inhibitor, on allergen-induced airway hyperresponsiveness in a mouse model. We sensitized and challenged mice with ovalbumin (OVA) to develop airway hyperresponsiveness as assessed by airway constriction and airway hyperreactivity (AHR) to methacholine (MCh) induced by allergen. The mice were orally treated with PBPB (0.1, 1 and 10 mg/kg) during or after OVA-sensitization and OVA-challenge to evaluate its protective or reversal effect on airway constriction and AHR to MCh. Determination of OVA-induced airway constriction and AHR to MCh were performed by measuring specific airway conductance (SGaw) using non-invasive dual-chamber whole body-plethysmography. We observed that PBPB (1 mg/kg) significantly reduced OVA-induced airway constriction and AHR to MCh (p<0.01). PBPB (1 mg/kg) treatment significantly inhibited PLA(2) activity in the BAL fluid. Cytokine analysis of the BAL fluid revealed that PBPB caused an increase in interferon-gamma (IFN-gamma) (p<0.02) and a decrease in interleukin-4 (IL-4) (p<0.05) and interleukin-5 (IL-5) (p<0.05) levels. The OVA-specific serum IgE levels (p<0.01) and the BAL eosinophils (p<0.001) were also reduced significantly. Thus, PBPB is capable of modulating allergen induced cytokine levels and serum IgE levels, and alleviating allergen induced airway hyperresponsiveness and eosinophils in mice. These data suggest that PBPB could be useful in the development of novel agents for the treatment of allergen induced airway hyperresponsiveness.

Psyllium-associated anaphylaxis and death: a case report and review of the literature.

BACKGROUND: Psyllium use has increased significantly in the United States in part due to its lipid-lowering property. The increased prevalence of consumption has led to its recognition as an emerging food allergen. OBJECTIVES: To report the case of a 42-year-old woman who experienced fatal anaphylaxis after ingesting a psyllium-based product and to review the literature. METHODS: The MEDLINE database was searched for articles from 1966 to 2002 using the keywords psyllium or ispaghula and each of the following: allergy, hypersensitivity, anaphylaxis, and asthma. Both English and non-English articles were included. RESULTS: Psyllium hypersensitivity has been well described in health care workers and pharmaceutical plant employees. Clinical manifestations of allergy range from upper respiratory tract symptoms on inhalation to anaphylaxis on ingestion. The prevalence of sensitization varies between these 2 groups. The allergenic epitope is not known. CONCLUSIONS: We present a case of psyllium hypersensitivity that resulted in death. There is a clear association between atopy and psyllium allergy. The case underscores the fact that even nonprescription "natural" products can be harmful to people with allergies.

Therapy-related café coronary deaths: two case reports of rare asphyxial deaths in patients under supervised care.

Café coronary deaths, as initially characterized, denote fatal occlusion of the upper airway by food substances. Such fatalities typically occur in individuals who either are clinically inebriated or have clinically significant neuromuscular dysfunction. Both conditions impair mastication and deglutition. The authors review the accidental deaths of two neurologically compromised patients under supervised care. Both subjects underwent complete medicolegal autopsy. In one case, ingestion of a prescribed emollient laxative precipitated death; in the other, death was attributable to aspiration of a contrast medium during a diagnostic radiographic procedure. These therapy-related deaths, which are regarded as a variation of the traditionally described café coronary fatalities summarized in the discussion, represent adverse events occurring during medical care. The adverse outcomes reviewed here are potentially avoidable and require special attentiveness by the clinicians directed to the particular condition of each patient. Such true aspiration-related deaths are confirmed on autopsy examination and are to be differentiated from the findings of agonal aspiration of gastric contents commonly encountered by the autopsy pathologist investigating deaths due to a great variety of natural and traumatic causes.

Life-threatening uvular angioedema caused by Ecbalium elaterium.

Ecbalium elaterium, known as the wild or squirting cucumber, is a hairy perennial herbaceous vine of the Cucurbitaceae family, endemic to the Mediterranean region. All parts of the plant are toxic, particularly the gherkin-like fruits. It is frequently used in the treatment of sinusitis by nasal aspiration in some parts of the Mediterranean. The studies regarding to Ecbalium elaterium, argue that it has an anti-inflammatory characteristic. Two cases of uvular oedema have been ascribed to the undiluted use of this substance. Since they can threaten life, similar cases arising with the improper use of herbals should not be ignored in the emergency department. In this paper we present a life-threatening uvular angioedema caused by nasal aspiration of undiluted juice of squirting cucumber.

The effect of maimendongtang on airway clearance and secretion.

We investigated the effect of Maimendongtang on airway clearance and secretion in anaesthetized quails. The oral application of 1 g/kg of Maimendongtang significantly increased tracheal mucociliary transport velocity (MCTV), whereas 100 or 300 mg/kg of Maimendongtang failed to do so. Moreover, 300 mg/kg or 1 g/kg of Maimendongtang markedly attenuated human neutrophil elastase (HNE) or DNA-induced decrease in MCTV although 100 mg/kg of Maimendongtang had little effect. Furthermore, we found that Maimendongtang significantly restored HNE-induced increases in DNA, fucose and protein contents of airway surface fluid (ASF), whereas only Maimendongtang itself significantly decreased the protein content. These results indicate that Maimendongtang increases MCTV and the increase may be, at least in part, ascribed to the amelioration of ASF in the trachea.

Upper airway anesthesia induces airflow limitation in awake humans.

Upper airway receptors are thought to contribute to upper airway stability by reducing collapsing forces. Their activity can be abolished by topical anesthesia. We have measured in 16 healthy volunteers (mean +/- SD age, 23.7 +/- 1.6 yr) specific airway conductance (SGaw), maximal inspiratory (MIFR) and expiratory (MEFR) flow rates before and 15, 35, and 45 min after extensive upper airway anesthesia (UAA) with 10% lidocaine. Average values of MIFR decreased (p less than 0.01) 15 min after UAA, but they returned to or near to control values at 45 min: MIF25 (4.8 versus 6.0 L/s); MIF50 (5.1 versus 6.2 L/s); MIF75 (4.4 versus 5.3 L/s). Transient decreases in flow (V) rates, reaching zero flow in some subjects, were observed in 13 subjects during forced inspiratory vital capacity (FIVC) maneuvers and in seven subjects during forced expiratory vital capacity (FEVC) maneuvers. MEFR at 25, 50, and 75% FVC, SGaw, and FVC did not change after anesthesia. Simultaneous measurements of supraglottic pressure, V, and lung volume in 12 of the 16 subjects showed that the site of flow limitation was localized at the level of the glottis in all except one subject in whom there was both a glottic and a supraglottic obstruction. We conclude that extensive upper airway anesthesia induced a profound but transitory upper airway obstruction during FIVC and FEVC maneuvers. These findings are compatible with the concept of reflex regulation of upper airway caliber.

Quartz but not iron oxide causes air-flow obstruction, emphysema, and small airways lesions in the rat.

Recent epidemiologic studies have suggested that some workers exposed to inorganic dusts develop air-flow obstruction independent of or greater than that produced by cigarette smoke; the morphologic basis of this effect is unknown. To investigate this problem, we administered saline alone, 10 mg iron oxide (an inert dust), or 10 or 30 mg of quartz to rats by intratracheal instillation. Animals were killed after 30 days, and pulmonary function and morphologic changes were examined. The iron oxide group was similar to the saline control group in all functional and morphometric parameters. However, both quartz-exposed groups showed evidence of air-flow obstruction, with more severe abnormalities in the high dose group. These findings correlated with morphometric observations of emphysema and thickened airway walls, with changes again more severe in the high dose group. Early silicotic nodules were also present in the latter animals. We conclude that in addition to the classic lesions of nodular silicosis, quartz can produce morphologic and functional changes of air-flow obstruction; no such changes are seen with iron oxide. These observations may explain the air-flow obstruction seen in workers exposed to mineral dusts.

Gasoline immersion injury.

Chemical burns and pulmonary complications are the most common problems encountered in the patient immersed in gasoline. Our patient demonstrated a 46-percent total-body-surface area, partial-thickness chemical burn. Although he did not develop bronchitis or pneumonitis, he did display persistent atelectasis, laryngeal edema, and subsequent upper airway obstruction. This had not previously been reported in gasoline inhalation injuries. Hydrocarbon hepatitis secondary to the vascular endothelial damage is apparently a reversible lesion with no reported long-term sequelae. Gasoline immersion injuries may be a series multisystem injury and require the burn surgeon to take a multisystem approach to its diagnosis and treatment.

Clinical pharmacology of beta-adrenoceptor antagonism in angina pectoris: an overview.

Beta antagonists competitively block beta 1-adrenoceptors that mediate both the rate and force of myocardial contraction. Their precise mechanism of anti-anginal action is uncertain. A reduction in oxygen demand may relative pain and improve effort tolerance. Alternatively inhibition of the adrenergic drive to contraction may offset the increased ventricular wall tension due to incomplete relaxation. Partial agonist activity in a beta-antagonist does not influence efficacy nor protect against airflow obstruction. Membrane stabilising activity is clinically trivial. Cardioselectivity makes airflow obstruction less likely at low but not at high blood concentrations of drug. Alpha-receptor antagonism may also prevent broncho-constriction; it has not been assessed in coronary vasospasm. The dosage and choice of drugs are based on pharmaco-kinetic and dynamic data in animals and man. The major side-effects of beta-blockade are heart failure and airflow obstruction. Cardiotoxicity from overdosage may be treated with isoprenaline, dopamine or glucagon while beta 2-agonists will reverse bronchoconstriction. Since beta-antagonists raise-peripheral vascular impedance, reduction of preload with nitrates enhances their antianginal efficacy. Combining a beta-antagonist with nifedipine seems especially useful. Beta-blockade is worth trying in angina with normal coronary arteries. In acute coronary insufficiency beta-blockade reduces both the work-load on the heart and the somatic features of anxiety, so preparing patients for investigations, like coronary arteriography, aimed at definitive treatment.

Protective effect of disodium cromoglycate against airway constriction induced by hemp dust extract.

The effect of disodium cromoglycate (DSCG) was studied in 14 healthy subjects following hemp dust extract (HDE) inhalation (10-min exposure). Ten subjects were given 20 mg of DSCG or a placebo and then challenged with dust aerosol at 30 min post-DSCG inhalation. Partial expiratory flow-volume (PEFV) curves were recorded at least 30 min after exposure, and maximum expiratory flow rates at 40% of the control vital capacity [MEF40%(P)] were read from these curves. Significant acute reduction in MEF40%(P) were recorded after HDE alone and after pretreatment with placebo (p less than 0.01). There was considerable protection from a single dose of 20 mg of DSCG against hemp-induced bronchoconstriction although the acute reductions in MEF40%(P) were still statistically significant at 20 and 30 men postexposure. A group of 7 subjects was given 40 mg of DSCG or placebo 30 min prior to HDE inhalation. In another experiment this group was given 20 mg of DSCG four times daily for 2 days, and on the third day challenged with HDE. The protective effect of DSCG is a short-term one: somewhat less protection was seen after 2 days of four times 20 mg of DSCG/day than 30 min after a single dose of 40 mg. Measurement of airway conductance (Gaw) in 6 subjects demonstrated prevention of acute reductions in Gaw at low lung volumes (25% VC) in 4 out of 6 subjects. We suggest that inhalation of 40 mg of DSCG prior to a work shift might be considered as a temporary means of protecting textile workers against the constrictor effects of dust in their work.