Evaluation of the Safety and Effectiveness of the Rapid Flow Expulsion Maneuver to Clear Subglottic Secretions in Vitro and in Vivo

Abstract

BACKGROUND: Clearing subglottic secretions has been proved to reduce ventilator-associated pneumonia. A manual method named the rapid flow expulsion maneuver was developed to clear subglottic secretions. This study evaluates its safety and effectiveness and analyzes the influential factors. METHODS: This study was composed of 2 parts. In an in vitro study, secretions were instilled directly to the area above the cuff in an intubated tracheal model. Secretions were expelled by the rapid flow expulsion maneuver with different volumes and peak flows in 3 tracheal positions (0, 15, and 30°). At each tracheal position, the maneuver was repeated twice, unless secretions above the cuff were <0.5 mL. In an in vivo study, subglottic secretions were suctioned via subglottic secretion drainage and then were cleared by the rapid flow expulsion maneuver. After the initial maneuver, methylene blue (2 mL) was instilled above the cuff, and the maneuver was performed again. The subject's sputum color was then recorded over 24 h. RESULTS: In the in vitro study, no aspiration was observed in the 277 maneuvers completed. Subglottic secretions were visibly expelled in 167 of 277 maneuvers (60.3%), and the median clearance efficiencies of the 3 consecutive maneuvers were 39.6, 6.3, and 0.4%. In the 108 first maneuvers, 93 (86.1%) produced visible secretions. Multiple linear regression models were used to identify predictors of clearance efficiency: tracheal position (P < .001), flow (P ‫؍‬ .041), and secretion viscosity (P ‫؍‬ .017). In the in vivo study, 77 rapid flow expulsion maneuvers were completed after suctioning via subglottic secretion drainage in 16 subjects, and the maneuvers collected 221.5 mL of secretions. No aspiration was observed over 24 h. CONCLUSIONS: The rapid flow expulsion maneuver was safe and effective to clear subglottic secretions. The first maneuver was the most effective to expel the majority of secretions. Supine position and high peak flow improved the clearance efficiency.

An Artificial Cough Maneuver to Remove Secretions From Below the Endotracheal Tube Cuff

“…The authors developed a manual technique that effectively removed subglottic secretions above the ETT cuff and prevented aspiration by deflating the ETT cuff and producing a high peak expiratory flow around the ETT cuff by a resuscitation bag. 23 Our prototype provides 2 further advancements compared to the technique proposed by Li et al, 23 which was aimed at removing subglottic secretions above the ETT cuff. Primarily, our technology is automated.…”

“…21 At that time, the technique was manual and did not involve the deflation of the ETT cuff, and the expiratory flow was centered within the inner diameter of the ETT and could only be guaranteed by the passive elastic recoil of the respiratory system (ie, the mechanically ventilated patient) or active patient expiration (in spontaneous breathing) with the addition, in some cases, of manual chest compressions. 22 Li et al 23 recently conceived a strategy of subglottic secretion drainage above the ETT cuff to address the issue of ventilator-associated pneumonia caused by the leakage of colonized subglottic secretions across the ETT cuff to the lower airways. The authors developed a manual technique that effectively removed subglottic secretions above the ETT cuff and prevented aspiration by deflating the ETT cuff and producing a high peak expiratory flow around the ETT cuff by a resuscitation bag.…”

Non-Pharmacological Interventions to Prevent Ventilator-Associated Pneumonia: A Literature Review

“…To overcome the absence of the cough reflex due to the presence of an ETT, an artificial cough maneuver known as rapid flow expulsion is used to clear secretions from the subglottic space: during expiration, the cuff is quickly deflated and a resuscitation bag is squeezed to increase the total gas flow. 100 In in vitro experiments, no aspiration was noted, and the maneuver showed good feasibility at the bedside. An automated system based on quick cuff deflations and inflations to simulate cough was recently proposed, but its use in the clinical scenario remains to be evaluated.…”

Artificial Cough Maneuvers: A New Method of Secretion Clearance?

“…To overcome these technological shortcomings, an innovative maneuver was recently proposed to clear subglottic secretions. 10 This maneuver requires a minimum of 2 experienced clinicians, one to produce a rapid flow by squeezing a resuscitation bag at the beginning of the patient's expiration, the other to manage the ETT cuff deflation-re-inflation. Although the maneuver seems to be safe and effective, its success relies on practitioner skill and understanding of the mechanism.…”

“…The large pressure gradient between the airway and oral cavity generates a rapid flow, which simulates a cough to move secretions from the airways to the oral cavity. 2,10 The secretions located in the central airway, around the tip of the ETT and cuff, and below and above the cuff, are expelled by the effective artificial cough.…”