Exhaled Air Dispersion During Noninvasive Ventilation via Helmets and a Total Facemask

Hui, David S.; Chow, Benny; Lo, Thomas; Ng, Susanna S.S.; Ko, Fanny W.S.; Gin, Tony; Chan, Matthew T. V.

doi:10.1378/chest.14-1934

Cited by 129 publications

(142 citation statements)

References 36 publications

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“…32 Broad dispersion of exhaled air during NIV via a face mask has previously been shown using a simulated patient encounter. 33 Although NIV was successfully used in a small number of SARS patients without documented nosocomial transmission, 13 other studies showed that NIV might have led to increased nosocomial transmission. 16,34 In our cohort, NIV failure was strikingly high and was associated with more requirements for inhaled nitric oxide.…”

Section: Discussionmentioning

confidence: 99%

Noninvasive ventilation in critically ill patients with the Middle East respiratory syndrome

Alraddadi

Qushmaq

Al-Hameed

et al. 2019

Influenza Resp Viruses

100

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Background Noninvasive ventilation (NIV) has been used in patients with the Middle East respiratory syndrome (MERS) with acute hypoxemic respiratory failure, but the effectiveness of this approach has not been studied. Methods Patients with MERS from 14 Saudi Arabian centers were included in this analysis. Patients who were initially managed with NIV were compared to patients who were managed only with invasive mechanical ventilation (invasive MV). Results Of 302 MERS critically ill patients, NIV was used initially in 105 (35%) patients, whereas 197 (65%) patients were only managed with invasive MV. Patients who were managed with NIV initially had lower baseline SOFA score and less extensive infiltrates on chest radiograph compared with patients managed with invasive MV. The vast majority (92.4%) of patients who were managed initially with NIV required intubation and invasive mechanical ventilation, and were more likely to require inhaled nitric oxide compared to those who were managed initially with invasive MV. ICU and hospital length of stay were similar between NIV patients and invasive MV patients. The use of NIV was not independently associated with 90‐day mortality (propensity score‐adjusted odds ratio 0.61, 95% CI [0.23, 1.60] P = 0.27). Conclusions In patients with MERS and acute hypoxemic respiratory failure, NIV failure was very high. The use of NIV was not associated with improved outcomes.

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Section: Discussionmentioning

confidence: 99%

Noninvasive ventilation in critically ill patients with the Middle East respiratory syndrome

Alraddadi

Qushmaq

Al-Hameed

et al. 2019

Influenza Resp Viruses

100

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“…Moreover, water content in the respiratory droplets may be evaporated and hence produce small droplet nuclei that are suspended in air. Nevertheless, the smoke particles used in this study mark the continuous air phase, and therefore our data indicated the anticipated "upper limits" of droplet dispersion [10][11][12][13][14][15][16]21 .…”

Section: Discussionmentioning

confidence: 54%

“…Our research team of investigators, consisting of a respiratory physician, an anesthesiologist/intensivist, and an aerodynamic architect that have jointly conducted and published a series of infection control experiments on a HPS (HPS 6.1, CAE Healthcare, Sarasota, FL) to display exhaled air dispersion quantitatively using a laser visualization technique during application of common respiratory therapies in different hospital ventilation settings [10][11][12][13][14][15][16] . In this study, we characterized the pattern of dispersion of potentially infected aerosols during two commonly performed procedures during resuscitation.…”

Section: Resultsmentioning

confidence: 99%

“…Smoke particles of <1 μm in diameter, produced by a M-6000 smoke generator (N19, DS Electronics, Sydney, Australia) was used to highlight exhaled airflow as previously described [10][11][12][13][14][15][16]21,24 . A 6 FG catheter was inserted into the right main bronchus of the HPS to deliver smoke particles.…”

Section: Flow Visualizationmentioning

confidence: 99%

“…After mixing with alveolar gas, smoke particles were exhaled through the normal airway passage. Leakage jet plume were then illuminated by a green (532 nm wavelength) laser light-sheet using a continuous pulse, diode-pumped solid state laser generator (OEM UGH-800 mW, Lambdapro Technologies, China) [10][11][12][13][14][15][16]21 . Assuming the intensity of the laser and the size or shape of the smoke particles remained constant during examination 24 , the intensity of light scattered by the smoke particles indicated the exhaled air smoke concentration.…”

Section: Flow Visualizationmentioning

confidence: 99%

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

Chan

Chow

et al. 2018

Sci Rep

Self Cite

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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.

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Respiratory support for adult patients with COVID‐19

Pavlov²,

et al. 2020

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The COVID‐19 pandemic is creating unique strains on the healthcare system. While only a small percentage of patients require mechanical ventilation and ICU care, the enormous size of the populations affected means that these critical resources may become limited. A number of non‐invasive options exist to avert mechanical ventilation and ICU admission. This is a clinical review of these options and their applicability in adult COVID‐19 patients. Summary recommendations include: (1) Avoid nebulized therapies. Consider metered dose inhaler alternatives. (2) Provide supplemental oxygen following usual treatment principles for hypoxic respiratory failure. Maintain awareness of the aerosol‐generating potential of all devices, including nasal cannulas, simple face masks, and venturi masks. Use non‐rebreather masks when possible. Be attentive to aerosol generation and the use of personal protective equipment. (3) High flow nasal oxygen is preferred for patients with higher oxygen support requirements. Non‐invasive positive pressure ventilation may be associated with higher risk of nosocomial transmission. If used, measures special precautions should be used reduce aerosol formation. (4) Early intubation/mechanical ventilation may be prudent for patients deemed likely to progress to critical illness, multi‐organ failure, or acute respiratory distress syndrome (ARDS).

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Exhaled Air Dispersion During Noninvasive Ventilation via Helmets and a Total Facemask

Abstract: A helmet with a good seal around the neck is needed to prevent nosocomial infection during NIV for patients with respiratory infections.

Cited by 129 publications

References 36 publications

Noninvasive ventilation in critically ill patients with the Middle East respiratory syndrome

Noninvasive ventilation in critically ill patients with the Middle East respiratory syndrome

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

Respiratory support for adult patients with COVID‐19

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