Bronchoalveolar lavage (BAL) has been proposed as a useful procedure f
or bacteriologic diagnosis of lower respiratory tract infection in mec
hanically ventilated patients. To determine the cardiopulmonary effect
s of this procedure and to identify the patients at risk of poor toler
ance, 30 critically ill ventilated patients suspected of having pneumo
nia were studied. Hemodynamic and gas exchange parameters were continu
ously recorded using an arterial catheter, a Swan-Ganz catheter with S
vO2 display, and a pulse oximeter. In addition to the basal sedation r
equired by these patients, midazolam, 0.1 mg/kg intravenously, was adm
inistered 5 min prior to bronchoscopy. A moderate increase (10 percent
from basal values) in heart rate, mean arterial pressure, and cardiac
index was recorded at each measurement during the procedure. A marked
decrease in PaO2 was observed during bronchoscopy associated with an
increase in oxygen consumption. Maximal changes in SaO2 and SvO2 were
recorded at the end of BAL. Two hours after the end of BAL, PaO2 value
s were still 20 percent lower than pre-BAL values in 40 percent of the
patients. We conclude that BAL can be performed safely in most critic
ally ill ventilated patients who have stable, hemodynamic and ventilat
ory parameters. However, none of the recorded parameters allows identi
fication of the patients at risk of poor tolerance of the procedure.