Sputum Induction

Sputum cytology is an established, low-cost test for lung cancer and an important method for detecting a variety of other diseases and pathological markers. For a sputum sample to be diagnostically useful, it must contain exfoliated or circulating cells from target areas of the lung, including both peripheral and central airways. Numerous studies demonstrate that high frequency chest compression (HFCC)/high frequency chest wall oscillation (HFCWO) used with nebulized saline solution or water yields larger, better quality sputum samples than other methods.

  1. Agostinis R, Man SFP, Mourad WA, Nguyen A, Thurber DL, Lien DC, Jones RL. High-frequency chest compression in combination with hypertonic saline improves induced sputum cytologic yield. Am J Crit Care Med 1995; 151:A844.

    In this assessment of the sputum-induction efficacy of a thirty-minute treatment with high-frequency chest compression (HFCC) combined with hypertonic saline (HS) solution, specimens from 9 subjects yielded significantly greater sputum volumes ( 4.9 vs 3.7 ml than with HS alone [p = < 0.05] and 0.76 ml with HFCC alone [ p = < 0.001]). Cell counts were higher (2.6x 109 vs. 2.1x 109 and 2.2X 109) respectively. A higher percentage of cells were derived from peripheral lung regions with a greater percentage of alveolar macrophages with combined HS/HFCC than when subjects were treated for an equal time with either saline solution or HFCC alone.
  2. Jones RL, Man SFP, Lien DC. Use of high-frequency chest compression plus hypertonic saline aerosol to provide sputum samples for diagnosis of lung cancer. Abstract presented at the Alberta Respiratory Diseases Symposium, Jasper, Alberta, 1995.

    Investigators used high frequency chest compression (HFCC) plus inhaled hypertonic saline (HS) as a sputum induction technique to determine the usefulness of the specimen for lung cancer diagnosis in patients with radiological abnormalities. Samples obtained by HFCC-HS and by “gold standard” bronchoscopy methods were sent to cytopathology for diagnosis and interpretation. HFCC – HS induced sputum was found to have a cytological sensitivity of 71%, specificity of 80%, positive predictive value of 63%, negative predictive value of 86% and an accuracy of 77%. Two of 22 patients yielded cells diagnostic of lung cancer with HFCC-HC but had negative bronchoscopies, suggesting the value the technique for the investigation of lung cancer.
  3. Lam S. Key issues in lung cancer chemoprevention trials of new agents. Cancer Res 2003; 163:182-195.
    This discussion of key issues in phase II trials of promising lung cancer chemopreventive agents includes the potential usefulness of sputum biomarkers. The author describes his success with high-frequency chest compression (HFCC)/high frequency chest wall oscillation (HFCWO) plus hypertonic aerosolized saline as a method to obtain specimens with both high specificity and sensitivity.
  4. McKinnon M, Payne P, MacAulay C, LeRiche JC, Lee A, Palcic B, Lam S. Optimal sputum cytology collection method. Chest 1996; 110:S1.
    To identify an optimal sputum cytology collection method, 52 heavy smokers were randomly assigned to produce sputum after 20 minutes of inhalation of nebulized water (NW) or induction with nebulized water +high frequency chest compresion (NW+ HFCC). Specimen adequacy was determined by presence of alveolar macrophages. Analysis showed that 90% of NW + HFCC specimens were adequate vs 74% NW; the fraction of normal, atypical and malignant bronchial epithelial cells (BEC) were 1.3 + 1.5% with NV + HFCC vs 0.97 + 1.0% with NW only; all NW+ HFCC samples contained BEC vs 93 % of those obtained with NW alone. NW + HFCC produced significantly more adequate specimens with higher yields of diagnostically important cells.
  5. Rhame F, Armstrong J, Beneke J, McComb C, Klous D, Sandowski P. Comparison of high frequency chest compression (HFCC) with hypertonic saline for the induction of sputum. Int Conf AIDS 1992; Jul 19-24; 8:51 (Abstract no. PuB 7017).
    In a study comparing the efficacy of sputum induction using high frequency chest compression (HFCC) with nebulized hypertonic saline (NHS), patients with HIV infection were randomized to either HFCC or NHS. Using recovery of alveolar macrophages as the outcome measure, both methods were judged adequate and similarly effective.

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