The effect of aspiration pressure over endobronchial ultrasound-guided transbronchial needle aspiration on the diagnosis of intrathoracic lymphadenopathies.

BACKGROUND: Data regarding the effect of aspiration pressure over endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) on the diagnosis of intrathoracic lymphadenopathies is limited. The aim of this study was to compare the effect of three levels of aspiration pressure over EBUS-TBNA on the diagnostic yield and numbers of diagnostic cells.
METHODS: A prospective study was conducted on 66 patients with enlarged intrathoracic lymph nodes. Three levels of aspiration pressure (0, 20, and 40 mL) were applied after the needle pierced the target and the needle's position was confirmed by EBUS images. The diagnostic yield and the numbers of diagnostic cells attained with each pressure from the same target were compared. The cellularity of the obtained diagnostic cells was classified into four grades (inadequate, minimal, moderate, and numerous) by a cytopathologist in a blinded study.
RESULTS: The mean nodal size was 19.1 ± 6.2 mm. The final diagnoses included 53 malignant and 13 benign lymphadenopathies. Adequate lymph node samples were obtained in 63 patients (95.5%), and EBUS-TBNA revealed definite diagnosis for 58 patients (87.9%). Negative pressure of 40 mL provided a diagnostic yield similar to that of 20 mL (83.3 vs. 75.8%; p = 0.23), but both showed higher diagnostic yields than zero pressure. In terms of cellularity of the specimen, however, high negative pressure (40 mL) gave higher numbers of adequate cells than the comparators (p < 0.001).
CONCLUSION: Negative pressure should be applied in an EBUS-TBNA procedure. Although the diagnostic yield was not different, high negative pressure was superior to low negative pressure in obtaining numbers of adequate cells.