Articles: intubation.
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J Anaesthesiol Clin Pharmacol · Aug 2020
Negative pressure aerosol containment box: An innovation to reduce COVID-19 infection risk in healthcare workers.
Healthcare workers (HCW's) are at increased risk of corona virus disease (COVID-19) infection during aerosol generating activities. The aerosol box has been used during intubation and extubation to prevent transmission of infection to HCWs. ⋯ The described containment box has been designed to be useful in COVID intensive care unit (ICU) as a multipurpose box which is a cost effective and readily available resource. This innovation combines the containment box with negative pressure generation using central vacuum.
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Why the interest?
The combination of a deadly contagion (COVID-19) and recognition that endotracheal intubation is a high risk procedure for the airway technician has lead to the development of novel medical equipment. One such innovation is the clear-perspex 'intubating box' designed to contain viral-aerosols released during intubation. There has been limited prior evaluation of the safety or efficacy of such devices, despite their promotion.
What did they do?
Begley et al. conducted 36 simulated intubations with twelve PPE-adorned1 anaesthetists, with and without intubating boxes. They primarily aimed to quantify the effect on time to intubation.
Investigators tested both a first-generation and newer generation device. Each of twelve senior anaesthesiologists performed three block-randomised intubations: no box, original, and latest-design box. The airway manikin tongue was inflated to simulate a grade 2A airway.
And they found...
Intubation time was significantly increased by both the older and newer box designs (x̄=48s and x̄=28s longer respectively, though with wide confidence intervals). More relevantly there were frequent prolonged-duration intubations with the box (58% >1 minute, 17% >2 min), but none without the box.
Most worrying, there were eight breaches of PPE caused by box use, seven occurring with the newer, more advanced design.
"PPE breaches often seemed to go unrecognised by participants, potentially increasing their risk further."
Reality check
Despite the superficial appeal of an intubation box, this simulation study warns that such devices fail both to support safe and timely intubation and to protect the clinician – the very arguments used to advocate for its use.
These failings occur before even considering the actual effectiveness in reducing viral exposure, the box's impact on emergent airway rescue, or the practicality of cleaning a reusable device now coated with viral particles.
The intubating aerosol box appears dead on arrival.
Bonus biases
Begley notes the appeal of such novel devices may be partly driven by 'gizmo idolatry' (Leff 2008) and 'MacGyver bias' (Duggan 2019), blinding clinicians to consider unknown consequences of box use and discounting resultant hazards.
summary
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Local COVID PPE guidelines were used: face-shield, goggles/glasses, mask, gown & gloves. ↩
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The number of patients requiring tracheal intubation rose dramatically in March and April 2020 with the COVID-19 outbreak. Our thoracic surgery department has seen an increased incidence of severe pneumomediastinum referred for surgical opinion in intubated patients with COVID-19 pneumonitis. ⋯ We hypothesise that the mechanism for this is the aggressive disease pathophysiology with an increased risk of alveolar damage and tracheobronchial injury, along with the use of larger-bore tracheal tubes and higher ventilation pressures. We present this case series in order to highlight the increased risk of this potentially life-threatening complication among the COVID-19 patient cohort and offer guidance for its management to critical care physicians.
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Videolaryngoscopes are crucial components of a difficult airway cart. Issues of cost and availability, however, remain a problem. We compared the combination of an endoscope used in conjunction with the Macintosh laryngoscope with established videolaryngoscopes and the Macintosh laryngoscope using the intubation difficulty scale (IDS) score. ⋯ The performance of videoendoscope was comparable to C-MAC D Blade and superior to Truview EVO2 and Macintosh laryngoscope with respect to the IDS score and may thereby provide an effective alternative to commercial videolaryngoscopes in low resource settings.