Objective: To identify parameters that
indicate retained secretions and the need for tracheal suctioning (TS)
in patients receiving mechanical ventilation (MV).
Design: Prospective observational study.
Setting: A 14-bed medical ICU in a 946-bed university
Patients: Sixty-six consecutive patients
Interventions: Two successive tracheal
suctions, TS1 and TS2, performed at a 2-h interval as usual patient
care. Retained secretions were considered significant if the volume of
secretions removed by TS2 was > 0.5 mL.
and results: Variations between TS1 and TS2 of pulse oximetric
saturation (Spo2), peak inspiratory pressure
(Ppeak), tidal volume (Vt), and Ramsay score were compared
between patients with TS2 ≤ 0.5 mL (group 1; n = 27) and patients
with TS2 > 0.5 mL (group 2; n = 39). The presence of a sawtooth
pattern on flow-volume loop displayed on the monitor screen of the
ventilator and of respiratory sounds heard over the trachea before TS2
were compared between the two groups. Variations of Ppeak,
Vt, Spo2, and Ramsay score between
TS1 and TS2 did not differ between the two groups. However, group 2 had
a sawtooth pattern (82% vs 29.6%; p = 0.0001) and respiratory
sounds (66.6% vs 25.9%; p = 0.001) more frequently than group 1
before TS2. For the sawtooth pattern, the likelihood ratio (LR) of a
positive test was 2.70 and the LR of a negative test was 0.25, while
for respiratory sounds it was 2.50 and 0.45, respectively. When the
presence of a sawtooth pattern and of respiratory sounds was combined,
the LR of a positive test rose to 14.7 and the LR of a negative test
Conclusions: A sawtooth pattern and/or
respiratory sounds over the trachea are good indicators of retained
secretions in patients receiving MV and may indicate the need for TS.
Conversely, the absence of a sawtooth pattern may rule out retained