Study objectives: Some respiratory units routinely
administer supplemental oxygen to all patients during flexible
bronchoscopy, but other units give oxygen only to those who desaturate
(arterial oxygen saturation [SaO2], < 90%). We
performed a study to examine both the requirement for supplemental
oxygen and the effect of IV midazolam therapy on oxygenation during
flexible bronchoscopy for patients with a known FEV1.
Design: Data on the SaO2 of patients
during flexible bronchoscopy were collected prospectively for all
procedures performed in our respiratory unit for the period 1992 to
Results: There were 1,051 flexible bronchoscopy
procedures performed in which the patient had a known FEV1
and was not receiving supplemental oxygen before the procedure.
Supplemental oxygen was commenced during or immediately after the
procedure in 151 cases (14.4%), while a further 101 cases (9.6%) had
momentary desaturation (ie, < 20 s) not requiring
oxygen therapy. The lower the FEV1, the greater the risk of
significant desaturation and the need for supplemental oxygen
(p < 0.0001) [supplemental O2 therapy was administered
in 35% of cases if FEV1 < 1.0 L, in 14% of cases if
FEV1 was 1.0 to 1.5 L, and in 7% of cases if
FEV1 > 1.5 L]. The use of low-to-moderate doses of
midazolam as sedation did not affect the probability of the occurrence
of significant desaturation (p = 0.204).
Conclusions: This study supports guidelines that suggest
that all patients should be monitored by pulse oximetry during flexible
bronchoscopy. Desaturation may occur at any FEV1 level even
without sedation. The majority of our patients did not require routine
oxygen supplementation, especially the group with an FEV1
above 1 L.