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Abstract

Introduction: The purpose of this study was to identify clinical cues for endotracheal (ET) suctioning in mechanically ventilated (MV) patients. Guidelines recommend auscultation of coarse crackles over the trachea and/or a sawtooth pattern on flow-volume loop of the ventilator waveform as the best indicators. Hypothesis: Audible crackles over the trachea and/or sawtooth pattern on the ventilator waveform will indicate the need for suctioning, defined as retrieval of? 1.0 mL secretions. Methods: This descriptive study was conducted in the critical care units following informed consent from the legal proxy. Forty adult subjects on MV with a respiratory waveform screen were enrolled; one was discontinued from MV, resulting in a sample size of 39 subjects. Closed-method ET suctioning was used on all. Following baseline ET suction, subjects were assessed hourly up to 4 hours for guideline-based cues for ET suctioning. When indicated, ET suctioning was done and secretion volume was measured. If no cues were present within 4 hours, suctioning was done at that time. Results: The majority of subjects were male (61.5%), Caucasian (92.3%), and on SIMV (84.6%) via ET tube (69.2%) with heat-moist exchanger humidification (53.8%). Mean (SD) age was 51.8 (20.7) years, and duration of MV 7.7 (6.2) days. The median time to ET suction was 2 hours; range 1-4 hours. All subjects had? 1.0 mL of mucus; range 1 to 15 mL; mean 4.5 (3.3) mL. Three subjects had no identified cues for suction within 4 hours, yet had secretions. Sensitivities of cues were coarse crackles over the trachea, 0.90; sawtooth waveform, 0.36; cough, 0.31. Related sample McNemar or t-test found improvements (p<.05) in tracheal sounds, waveform, peak inspiratory pressure, and oxygenation after suction. Sensitivity of coarse lung sounds was 0.39; lung sounds did not improve after suction. Since? 1.0 mL mucus was retrieved in all, specificity was not calculated. Conclusions: Auscultation of coarse crackles over the trachea is a specific indicator for the need for suction. Assessment every two hours is recommended. Patients may need suction at least every 4 hours, even without clinical cues. Despite common practice, assessment of lung sounds is not recommended as a cue.