Am. J. Respir. Crit. Care Med., Vol 149, No. 2, Feb 1994, 320-323.
Quantitative cultures of protected brush specimens and bronchoalveolar lavage in ventilated patients without suspected pneumonia
F Rodrguez de Castro, J Sole and R Elcuaz
Section of Pneumology, Hospital Universitario Ntra. Sra. del Pino, Las Palmas de Gran Canaria, Spain.
Quantitative bacterial cultures of protected specimen brush (PSB) and
bronchoalveolar lavage (BAL) specimens were used to assess the presence of
distal bronchial microflora in mechanically ventilated patients who were
not suspected of having pneumonia. A total of 54 specimens from 32 ICU
patients were obtained. In 10 patients, only PSB specimens were recovered,
whereas in 22 patients both PSB and BAL specimens were obtained. Cultures
demonstrated no growth in 10 (45%) of the 22 samples recovered by BAL and
in 21 (66%) of the 32 samples recovered by the PSB method. Twenty-three
specimens yielded microorganisms, but in only six patients was a
significant growth in PSB and/or BAL cultures (> or = 10(3) and > or
= 10(5) cfu/ml, respectively) detected. Four of these patients developed
pneumonia on subsequent follow-up. In mechanically ventilated patients, the
diagnostic thresholds of bacterial growth in PSB and BAL cultures may be
misleading. A significant relationship was found between the ability of PSB
to recover microorganisms and the duration of mechanical ventilation (p
< 0.05). These findings may be a limitation present in all patients
receiving prolonged mechanical ventilation.
