Exhaled nitric oxide in the diagnosis and management of asthma: clinical implications.

Exhaled nitric oxide (eNO) used as an aid to the diagnosis and management of lung disease is receiving attention from pulmonary researchers and clinicians alike because it offers a noninvasive means to directly monitor airway inflammation. Research evidence suggests that eNO levels significantly increase in individuals with asthma before diagnosis, decrease with inhaled corticosteroid administration, and correlate with the number of eosinophils in induced sputum. These observations have been used to support an association between eNO levels and airway inflammation. This review presents an update on current opportunities regarding use of eNO in patient care, and more specifically on its potential usage for asthma diagnosis and monitoring. The review will also discuss factors that may complicate use of eNO as a diagnostic tool, including changes in disease severity, symptom response, and technical measurement issues. Regardless of the rapid, convenient, and noninvasive nature of this test, additional well-designed, long-term longitudinal studies are necessary to fully evaluate the clinical utility of eNO in asthma management.

Multiple flow rates measurement of exhaled nitric oxide in patients with sarcoidosis: a pilot feasibility study.

Fraction of end tidal exhaled nitric oxide (FeNO) has been introduced as a non-invasive marker of airway inflammation in patients with asthma and may have value in monitoring disease activity in patients with sarcoidosis. This pilot study explored: 1) feasibility of the multiple flow rates maneuver to estimate alveolar (C(AlV)NO) and airway wall (J(AW)NO) NO in patients with sarcoidosis; and 2) utility of exhaled NO (FeNO, C(Alv)NO and J(AW)NO) measurements to detect and monitor treatment response in patients with active pulmonary sarcoidosis. Patients with sarcoidosis (n = 42) and healthy non-smokers (n = 20) underwent FeNO measurement at 7 flow-rates (50 to 400 ml/s). Using the Tsoukias and George (1998) model, C(Alv)NO and J(AW)NO were estimated. Both patients and healthy non-smokers were able to perform the multiple flow rates maneuver without discomfort, with first measurement success rate of 57% and 65%, respectively. No significant difference was found between patients with sarcoidosis and healthy non-smokers in exhaled NO. None were correlated with pulmonary function tests, except a significant negative correlation between C(Alv)NO and FVC% (p = 0.001) and DLCO% (p = 0.012). In 8 patients with active sarcoidosis, FeNO, C(Alv)NO or J(AW)NO were not different from those of patients with inactive sarcoidosis. Treatment of active sarcoidosis using oral prednisone and methotrexate did not show any consistent pattern of changes in C(Alv)NO or J(AW)NO. Due to a large inter-subject variability and difficulty controlling use of the inhaled corticosteroids, exhaled NO measurement did not appear to be a clinically useful method of monitoring disease progression in sarcoidosis.

Smoking and chronic obstructive pulmonary disease.

Smoking is overwhelmingly the major cause of chronic bronchitis and emphysema worldwide. Additional risk factors for developing COPD are presented, along with the variables that govern cigarette smoke deposition in the lung. Major paradigms for the pathogenesis of COPD, including the protease-antiprotease and oxidant-antioxidant theories are described, and evidence for impaired reparative mechanisms in the causation of emphysema is noted. A description of the natural history of declining lung function in smokers and in the susceptible subset of smokers that ultimately develop smoking-induced COPD is accompanied by a discussion of the effects of smoking cessation on preservation of lung health. The disordered ventilation and gas-exchange physiology in the cigarette smoke-damaged lung is explained on the basis of the observed morphological changes.

Mechanical ventilation in chronic obstructive lung disease.

Exacerbations of COPD are a leading indication for MV in the intensive care unit. A thorough understanding of the pathophysiology of AVF in COPD is critical for physicians caring for these patients. In particular, physicians should understand DHI and use the ventilator and ancillary techniques to minimize its impact. Noninvasive positive-pressure ventilation should be considered strongly in relatively stable patients with an adequate mental status and manageable secretions. Once AVF resolves, patients should be removed from the ventilator as soon as is safe to do so to minimize the adverse effects of prolonged MV. An organized approach to weaning and identifying patients capable of independent breathing is crucial. Most patients with COPD and AVF benefit from MV and generally return to or approach their premorbid functional status. A significant subset, however, will not benefit from, or choose not to undergo, MV. Deciding upon appropriate therapeutic options for these patients relies heavily on effective communication between physician and patient. Comprehensive discussions before the development of AVF can assist decision-making after respiratory failure develops.

Guillain-Barré syndrome: rehabilitation outcome and recent developments.

Guillain-Barré syndrome is the most common polyneuropathy causing major disability and respiratory failure. Respiratory complications are the main cause of death. Improved respiratory care and new treatment strategies such as plasmaphoresis and immunoglobulin have been shown to improve outcome. We studied the course and outcome of 37 patients with Guillain-Barré syndrome who were admitted to a rehabilitation and respiratory care facility over a 10-year period. There were 21 males and 16 females with a mean age of 62+/-3 years. Fourteen patients developed respiratory failure requiring endotracheal intubation and mechanical ventilation. The mean duration of mechanical ventilation was 38+/-10 days. All patients were successfully liberated from the ventilator. However, 83 percent of the patients were moderately to severely disabled at the time of discharge. Thirteen out of 37 (35 percent) developed long-term disability. None of the patients died over the period of follow-up. These results indicate that early recognition and treatment of respiratory complications in Guillain-Barré syndrome could reduce the morbidity and mortality of this condition.

Internal carotid artery embolism by shotgun pellet.

Various examples of foreign body embolization of cerebral arteries, usually followed by serious consequences, have been reported (Lindberg et al., 1961; Chason et al., 1963; Steele et al., 1972; Wetli et al., 1972). However, a shotgun pellet entering the left atrium of the heart through a gunshot wound of the chest with subsequent embolic occlusion of one of the carotid arteries appears to be unique. It is the subject of this short communication.

Urethral striated sphincter responses to electro-bulbocavernosus stimulation.

Electric stimuli of known strength, duration and frequency were applied to the glans penis, and the cystosphincterometric and electromyographic responses of the urethral striated sphincter were recorded. Studies performed on male subjects, including normal men, patients with a neurologic deficit and patients who had undergone prostatectomy, indicate the usefulness of this technique in evaluating the striated sphincter excitability via the pudendal reflex arc. The intravenous administration of diazepam produced a notable increase in the striated sphincter threshold, indicating the applicability of this technique to evaluate the effect of various neuropharmacologic agents on the striated sphincter activity. In addition, the transit time through the pudendal reflex arc was measured with this method to assess the somatic neural integrity of the lower urinary tract. Also, studies on patients with post-radical prostatectomy incontinence have suggested that our technique of striated sphincter evaluation could be applied to the prediction of postoperative urinary incontinence.