Effect of high-frequency chest wall oscillation on the central and peripheral distribution of aerosolized diethylene triamine penta-acetic acid as compared to standard chest physiotherapy in cystic fibrosis

Background and objectives: High-frequency chest wall oscillation (HFCWO) has been shown to be as effective as standard chest physiotherapy (SCPT) for removal of pulmonary secretions as well as increasing FEV1 in cystic fibrosis (CF) patients. Patients using HFCWO often administer aerosolized medications simultaneously, reducing time required for daily care. While peripheral pulmonary distribution of tracer in normal subjects has been shown to be unaffected by HFCWO, this has not been studied in CF patients. We evaluated distribution of aerosolized Tc-99m diethylene triamine penta-acetic acid (DTPA) administered simultaneously with HFCWO and compared this with DTPA aerosolized after SCPT. Study design: Ten CF patients, ages 22 to 38 years, with moderate-to-severe obstructive disease were studied in a crossover design after documentation of stable lung function. (XC)-X-133 was administered to delineate total lung volume. DTPA was aerosolized (Pari LC Plus nebulizer and Pulmo-Aide compressor; Pari Respiratory Equipment Inc.; Richmond, VA) to delineate airway deposition. The central to peripheral deposition ratio (C/P ratio) of each lung was analyzed in each study group. Central regions were represented by the inner one third of the Xe-133 scan as demonstrated in previous research models. Results: The mean C/P ratio (+/- SD) for both lungs was 1.45 +/- 0.31 with HFCWO and 1.46 +/- 0.28 following SCPT (p = not significant [NS]). Right lung mean C/P ratio was 1.74 +/- 0.43 with HFCWO and 1.85 +/- 0.63 after SCPT (p NS). Left lung mean C/P ratio was 1.25 +/- 0.29 with HFCWO and 1.21 +/- 0.35 after SCPT (p NS). There was no correlation between C/P ratio and FEV1 or FVC. Conclusions: Use of HFCWO in combination with aerosolized DTPA did not result in increased central deposition as compared with aerosolized DTPA administered after SCPT. Further study is required to determine if combining HFCWO with aerosolized medications can be modified to improve peripheral deposition.