Bedside Detection of Retained Tracheobronchial Secretions in Patients Receiving Mechanical Ventilation

Objective: To identify parameters thatindicate 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 universityhospital. Patients: Sixty-six consecutive patientsreceiving MV. Interventions: Two successive trachealsuctions, TS1 and TS2, performed at a 2-h interval as usual patientcare. Retained secretions were considered significant if the volume of secretions removed by TS2 was > 0.5 mL. Measurementsand results: Variations between TS1 and TS2 of pulse oximetricsaturation (Sp o 2 ), peak inspiratory pressure(Ppeak), tidal volume (V t ), and Ramsay score were comparedbetween patients with TS2 ≤ 0.5 mL (group 1; n = 27) and patientswith TS2 > 0.5 mL (group 2; n = 39). The presence of a sawtoothpattern on flow-volume loop displayed on the monitor screen of theventilator and of respiratory sounds heard over the trachea before TS2were compared between the two groups. Variations of Ppeak, V t , Sp o 2 , and Ramsay score betweenTS1 and TS2 did not differ between the two groups. However, group 2 hada sawtooth pattern (82% vs 29.6%; p = 0.0001) and respiratorysounds (66.6% vs 25.9%; p = 0.001) more frequently than group 1before TS2. For the sawtooth pattern, the likelihood ratio (LR) of apositive test was 2.70 and the LR of a negative test was 0.25, whilefor respiratory sounds it was 2.50 and 0.45, respectively. When thepresence 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 testwas 0.42. Conclusions: A sawtooth pattern and/orrespiratory sounds over the trachea are good indicators of retainedsecretions in patients receiving MV and may indicate the need for TS. Conversely, the absence of a sawtooth pattern may rule out retainedsecretions.