Ex Vivo Evaluation of Secretion-Clearing Device in Reducing Airway Resistance within Endotracheal Tubes

Evaluation of a Closed Suction System With Integrated Tube-Scraping Technology

BACKGROUND

Endotracheal tube (ETT) scraping or sweeping refers to mucus removal from an ETT that can increase airway resistance. The study objective was to evaluate the effect of ETT scraping on the duration of mechanical ventilation, time to first successful spontaneous breathing trial (SBT), duration of hospital stay, and occurrence of ventilator-associated events (VAEs).

METHODS

This was a single-center, randomized clinical trial of adult subjects intubated between October 2019-October 2021. Subjects were randomly assigned to either ETT suctioning via a standard in-line suction catheter (control group) or ETT suctioning and scraping via a suction catheter with balloon-sweeping technology (experimental group). Airway suctioning was performed as clinically indicated, and the ETT was scraped every time a respiratory therapist suctioned the subject. The study outcome was duration of mechanical ventilation, time to first successful SBT, hospital length of stay, and VAE rate. Intent-to-treat statistical analysis was performed.

RESULTS

Of 272 randomized subjects, the median age was 63 (interquartile range [IQR] 52-73) y; 143 (53%) were males, and 154 (57%) had a primary diagnosis of acute respiratory failure. There were no significant differences between the groups in median duration (h) of mechanical ventilation (72 [37-187] vs 70.6 [37-148], P = .58). There was no significant difference between the study groups in median time (h) to the first successful SBT (46.7 [IQR 30-87] vs 45.7 [IQR 27-95], P = .81), length of hospital stay (P = .76), the incidences of ventilator-associated conditions (P = .13), or infection-related ventilator-associated complications (P = .47).

CONCLUSIONS

ETT suctioning plus scraping, compared to ETT suctioning alone, did not significantly improve the duration of mechanical ventilation, time to first successful SBT, length of hospital stay, and VAEs. These study findings do not support the routine use of ETT scraping for mechanically ventilated patients.

AARC Clinical Practice Guidelines: Artificial Airway Suctioning

Artificial airway suctioning is a key component of airway management and a core skill for clinicians charged with assuring airway patency. Suctioning of the artificial airway is a common procedure performed worldwide on a daily basis. As such, it is imperative that clinicians are familiar with the most-effective and efficient methods to perform the procedure. We conducted a systematic review to assist in the development of evidence-based recommendations that pertain to the care of patients with artificial airways. From our systematic review, we developed guidelines and recommendations that addressed questions related to the indications, complications, timing, duration, and methods of artificial airway suctioning. By using a modified version of the RAND/UCLA Appropriateness Method, the following recommendations for suctioning were developed for neonatal, pediatric, and adult patients with an artificial airway: (1) breath sounds, visual secretions in the artificial airway, and a sawtooth pattern on the ventilator waveform are indicators for suctioning pediatric and adult patients, and an acute increase in airway resistance may be an indicator for suctioning in neonates; (2) as-needed only, rather than scheduled, suctioning is sufficient for neonatal and pediatric patients; (3) both closed and open suction systems may be used to safely and effectively remove secretions from the artificial airway of adult patients; (4) preoxygenation should be performed before suctioning in pediatric and adult patients; (5) the use of normal saline solution should generally be avoided during suctioning; (6) during open suctioning, sterile technique should be used; (7) suction catheters should occlude < 70% of the endotracheal tube lumen in neonates and < 50% in pediatric and adult patients, and suction pressure should be kept below -120 mm Hg in neonatal and pediatric patients and -200 mm Hg in adult patients; (8) suction should be applied for a maximum of 15 s per suctioning procedure; (9) deep suctioning should only be used when shallow suctioning is ineffective; (10) routine bronchoscopy for secretion removal is not recommended; and (11) devices used to clear endotracheal tubes may be used when airway resistance is increased due to secretion accumulation.

Tracking respiratory mechanics around natural breathing rates via variable ventilation

Measuring respiratory resistance and elastance as a function of time, tidal volume, respiratory rate, and positive end-expiratory pressure can guide mechanical ventilation. However, current measurement techniques are limited since they are assessed intermittently at non-physiological frequencies or involve specialized equipment. To this end, we introduce ZVV, a practical approach to continuously track resistance and elastance during Variable Ventilation (VV), in which frequency and tidal volume vary from breath-to-breath. ZVV segments airway pressure and flow recordings into individual breaths, calculates resistance and elastance for each breath, bins them according to frequency or tidal volume and plots the results against bin means. ZVV's feasibility was assessed clinically in five human patients with acute lung injury, experimentally in five mice ventilated before and after lavage injury, and computationally using a viscoelastic respiratory model. ZVV provided continuous measurements in both settings, while the computational study revealed <2% estimation errors. Our findings support ZVV as a feasible technique to assess respiratory mechanics under physiological conditions. Additionally, in humans, ZVV detected a decrease in resistance and elastance with time by 12.8% and 6.2%, respectively, suggesting that VV can improve lung recruitment in some patients and can therefore potentially serve both as a dual diagnostic and therapeutic tool.