Chest
Volume 118, Issue 4, October 2000, Pages 1095-1099
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Clinical Investigations in Critical Care
Bedside Detection of Retained Tracheobronchial Secretions in Patients Receiving Mechanical Ventilation: Is It Time for Tracheal Suctioning?

https://doi.org/10.1378/chest.118.4.1095Get rights and content

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 (Spo2), peak inspiratory pressure(Ppeak), tidal volume (Vt), 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, Vt, Spo2, 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.

Section snippets

Materials and Methods

The study was performed in a 14-bed medical ICU of Saint-AntoineHospital, a 946-bed university hospital. It was conducted according tothe local Ethics Committee Guidelines for Human Research. Informedconsent was obtained from each patient or the nearest next of kin.

All consecutive patients receiving MV with the Cesar ventilator (CFPO;Paris, France) or the T-Bird ventilator (SEBAG; Pantin, France)were included. Both ventilators display real-time flow-volume loops ontheir monitor screen. Either

Results

Sixty-six patients were studied. Their characteristics arepresented in Table 1. Thirty-nine patients (59%) had TS2 > 0.5 mL (group 2). The meanvolume of removed secretions by TS2 was 2.6 ± 2.5 mL (range, 0.6 to12 mL) in group 2, and 0.1 ± 0.1 mL (range, 0.0 to 0.5 mL) in group1. The mean time elapsed between TS1 and TS2 was 122 ± 38 min.

Variations of Ppeak, Vt,Spo2, and Ramsay score between TS1and TS2 did not differ between the two groups (Table 2). However, group 2 had a sawtooth pattern (82%

Discussion

In this prospective study, we observed that the presence of asawtooth pattern on the flow-volume loop displayed on the monitorscreen of the ventilator or the presence of respiratory sounds over thetrachea accurately indicates the presence of retained tracheobronchialsecretions in ICU patients receiving MV, and may indicate the need for TS. Conversely, modifications of the respiratory pattern, Spo2, or Ramsay score fail toidentify patients with retained secretions.

The sawtooth pattern is a

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