close attention objectives: Induced sputum is used to investigate pulmonary diseases.

close attention objectives: Induced sputum is used to investigate pulmonary diseases. Low-output ultrasonic nebulizers have become available and have potential advantages from one side of to the other high-output nebulizers. We hypothesized that a low-output nebulizer would give comparable deductions to a high-output nebulizer, with an acceptable safety profile.

Design: Randomized, crossover study

Setting: University teaching hospital.

Participants: Ten normal enthralls and 10 patients with COPD

Interventions: Participants attended for sputum induction onward two occasions in random order using low-output and high-output nebulizers.

Measurements and results: Lung function and oxygen saturation were measured during sputum induction, and tolerability of the act was assessed. Cell counts, interleukin 8 and neutrophil elastase were measured in sputum Use of the high-output nebulizer deductioned in a greater FE[V.sub.1] (mean [+ or -] SEM 029 [+ or -] 004 L v 021 [+ or -] 004 L; p = 004) and percentage least bit in FE[V.sub.1] (25.8 [+ or -] 26% v 195 [+ or -] 29% respectively; p = 002) compared with the low-output nebulizer in patients with COPD There was a shorter tolerated nebulization time with the high-output nebulizer compared with the low-output nebulizer: 127 [+ or -] 20 min v 165 [+ or -] 18 min, respectively (p = 002) Modified Borg scores were lower with the low-output nebulizer than the high-output nebulizer in normal subjects: median, 0 (interquartile range [IQR], 0 to 1) v median, 15 (IQR, 0 to 2) respectively (p = 005) There were no differences in solitary abode; squalid counts and soluble markers of inflammation.

Conclusions: The low-output ultrasonic nebulizer is comparable to high-output nebulizer for cellular and soluble markers of inflammation, accrues in a smaller reduction in FE[Vsub1] is better tolerated, and is a suitable tool for investigating airway inflammation in patients with COPD

key-note words: COPD; induced sputum; ultrasonic nebulizer

Abbreviations: IL = interleukin; IQR = interquartile range; mB = modified Borg score; NE = neutrophil elastase; VAS = visual analog score

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COPD is an inflammatory disorder characterized by the agency of neutrophilic inflammation in airway secretions, with a predominance of macrophages and lymphocyte forward biopsy. (1) Bronchoscopic investigations are frequently not possible due to severity of disease. Since the 1980 induced sputum has been used as a tool to investigate pulmonary diseases. It is les invasive and bears valid, repeatable results. (2-4)

principally studies use high-output ultrasonic nebulizers that deliver a large bulk of hypertonic saline solution to the airways. More freshly low-output ultrasonic nebulizers have become available, which deliver a smaller dimensions over the same time. These have been used predominantly in asthma research. (56) not many studies have reported the use of low-output nebulizers in patients with COPD and no comparisons have been made with the high-output type

We hypothesized that a low-output nebulizer would give comparable arises to a high-output nebulizer, with an acceptable safety profile. The aim was to compare the sum of two units types of ultrasonic nebulizers, in normal enthralls and patients with COPD, using the lowest concentration of saline solution (3%) This minimizes the load of saline solution delivered and is likely to be les irritant to the airways.

MATERIALS AND METHODS

Participants

Normal Subjects: Ten normal nonsmoking make subordinates (5 men) with no latter serious concomitant illnesses, history of atopy or asthma, or history of childhood chest disease were recruited: mean [+ or -] SEM age, 28 [+ or -] 1 years; FE[Vsub1] 365 [+ or -] 09 L; and FE[Vsub1] percent of predicted, 981 [+ or -] 32%

Patients With COPD: Ten patients (7 men) with stable COPD attending the Belfast City Hospital Respiratory Medicine clinics were also recruited: mean age, 63 [+ or -] 3 years; FE[Vsub1] 108 [+ or -] 014 L; FE[Vsub1] percent predicted, 407 [+ or -] 42%; throb oximetric saturation, 91.4 [+ or -] 18%; and median cigarette consumption, 435 pack-years (interquartile range [IQR], 40 to 475 pack-years). The patients with COPD were choiceed based on a clinical history consistent with COPD as described in British Thoracic Society guidelines. (7) We recruited patients > 40 years not new with a [greater than or equal to] 20 pack-year history of smoking, FE[Vsub1] < 70% FE[Vsub1]/FVC ratio < 75% and < 15% reversibility in reply to inhaled [[beta].sub.2]-agonists. Patients were exclud if they were receiving long-term oral steroids, had any evidence of other inflammatory disorders, or had a history of respiratory tract infection in the last month The Queen's University of Belfast Faculty of Medicine Research Ethics Committee approved the contemplation and informed written consent was obtained from all patients

Sputum Induction

Spirometry was undertaken, and reversibility to salbutamol was experimented in the patients with COPD Fifteen minutes after inhalation of 200 [micro]g of salbutamol, the patients rinsed their openings with water. Spirometry was recorded to assess reversibility, and oxygen saturation and oscillation rate were measured using a beating [i]or[/i] throbbing of an artery oximeter (Sat-Trak Pulse Oximeter; SensorMedics; Bilthoven, the Netherlands). make submissives were randomized to either the high-output nebulizer (DeVilbiss Ultraneb 99; DeVilbiss Healthcare; somersault PA) or the low-output nebulizer (Sonix 2000; tender Clarke International; Harlow, Essex, UK) initially, followed by means of the other nebulizer at least 1 week later. Randomization was achieved using random-number tables. The high-output nebulizer was wager at approximately 3 mL/min (mean particle size < 4 [micro]m), and the low-output nebulizer was wager at approximately 0.4 mL/min (mean particle size of 49 [micro]m).

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