Exhaled air dispersion during bag-mask ventilation and sputum suctioning - Implications for infection control

Abstract

Mask ventilation and coughing during oro-tracheal suctioning produce aerosols that enhance nosocomial transmission of respiratory infections. We examined the extent of exhaled air dispersion from a human-patient-simulator during mask ventilation by different groups of healthcare workers and coughing bouts. The simulator was programmed to mimic varying severity of lung injury. Exhaled airflow was marked with tiny smoke particles, and highlighted by laser light-sheet. We determined the normalized exhaled air concentration in the leakage jet plume from the light scattered by smoke particles. Smoke concentration ≥20% was considered as significant exposure. Exhaled air leaked from mask-face interface in the transverse plane was most severe (267 ± 44 mm) with Ambu silicone resuscitator performed by nurses. Dispersion was however similar among anesthesiologists/intensivists, respiratory physicians and medical students using Ambu or Laerdal silicone resuscitator, p = 0.974. The largest dispersion was 860 ± 93 mm during normal coughing effort without tracheal intubation and decreased with worsening coughing efforts. Oro-tracheal suctioning reduced dispersion significantly, p < 0.001, and was more effective when applied continuously. Skills to ensure good fit during mask ventilation are important in preventing air leakage through the mask-face interface. Continuous oro-tracheal suctioning minimized exhaled air dispersion during coughing bouts when performing aerosol-generating procedures.

COVID-19 and Neonatal Respiratory Care: Current Evidence and Practical Approach

“…54 In a series of physiological experiments, Chan et al programmed an adult simulator to mimic varying severities of lung injury. 55,56 When a tidal volume (VT) of 300 mL was applied, air dispersion reached up to 0.3 to 0.35 m. Presumably, lower VT would produce less air dispersion. Indeed, in another experiment using noninvasive ventilation, a five-fold decrease in VT was associated with a 30% reduction in air dispersion.…”

“…Technical skills to minimize exhaled air dispersion is also paramount since inexperienced HCW can increase the spread by 40%. 55 Thus, in neonatal respiratory care, avoidance of manual ventilation solely for the purpose of preventing air dispersion appears unnecessary.…”

“…To further protect HCW during manual ventilation, several NICUs have also embraced the use of bacterial/viral filters. While the filter is effective in reducing viral dispersion, 55,56 there are important considerations to its use. For example, addition of a filter can increase the bulk of the device and reduce efficiency by increasing mask leaks.…”

“…53 However, some evidence from adult studies suggests that in nonintubated patients, continuous suctioning may be more effective at reducing aerosol dispersion compared with intermittent suctioning. 55 Noninvasive Respiratory Support CPAP and nasal intermittent positive pressure ventilation (NIPPV) may play a supportive role in infants with viral pneumonia and early ARDS. Considering that some viral infections can convert from droplets to airborne during respiratory therapy, it is possible that CPAP and NIPPV Table 3 Practical approach to neonates with suspected or conformed COVID-19…”

Practical considerations for performing regional anesthesia: lessons learned from the COVID-19 pandemic

“…19 Other than the general benefits of reduced pain and opioid consumption, postoperative pulmonary complications, postoperative nausea and vomiting, and possibly postoperative cognitive dysfunction and delirium offered by RA over GA (with systemic opioids), 20 the main advantage in patients with infectious respiratory viral diseases would be the avoidance of airway instrumentation and patient coughing during intubation and extubation, 21,22 thus reducing the risk of infecting staff via the associated aerosol generation and dispersion of viral particles. 23 Secondly, and broadly speaking, RA has fewer effects on respiratory function and dynamics compared with GA with or without muscle paralysis. [24][25][26] This relative preservation of respiratory function could theoretically reduce postoperative pulmonary complications in COVID-19 patients who may already have reduced respiratory function from COVID-19-associated pneumonia or acute respiratory distress syndrome.…”