Look Ma, No Hands: Jaw Thrust Device For ECT Anesthesia
Out on PubMed, from an anesthesiologist in India, is this report:
Utility of a novel airway collar in electroconvulsive therapy - A handsfree technique.
Korean J Anesthesiol. 2021 Dec 9. doi: 10.4097/kja.21481. Online ahead of print.PMID: 34883009
This is an interesting technical innovation in anesthesia technique; whether it is necessary or helpful, I'm not sure. Perhaps the more interesting part of this technique is the insufflation device that replaces bag/mask ventilation of the patient, something touted during the current COVID pandemic to avoid aerosolization in the treatment room.
It would be good to hear some opinions as to whether this technique is regarded favorably as an addition to the possible technical approaches to ECT anesthesia, or if it just seems glitzy and not worth the bother...
All followers of the ECT anesthesia literature will want to read this brief LTE.
This is a very exciting technical development. Of course, it remains to be seen whether such a technique can really be applied to every patient. In any case, I find it remarkable that more than five times as much oxygen is used, which is not an unimportant aspect nowadays, since oxygen can already be considered the most expensive consumable in ECT.
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ReplyDelete(…continued from prior comment) Interestingly, prior studies of THRIVE devices (like the one pictured above) suggest that they don't strictly work by passive oxygenation. Indeed, there is clear evidence that these devices, which rely on high oxygen flows (greater than 30L/min...for reference, a standard facemask typically delivers O2 at 6-8L/min while a standard nasal cannula typically delivers flows of 2-4L/min), are actually contributing to ventilation through bulk gas exchange. In other words, patients on these devices do continue to off-load CO2 from the lungs. This form of ventilation most likely occurs through simple mass action due to the constant introduction of large volumes of fresh oxygen to the open respiratory system. True, there may be no movement of the diaphragm and no bellows-like action of the lungs, but a form of positive pressure ventilation is nonetheless demonstrably occurring in patients who are under a combination of general anesthesia and full muscle relaxation while using one of these devices. Without a sealed bag-valve mask device or an endotracheal tube in place, this positive pressure ventilation is occurring in an open circuit. The implication here is that this approach may not truly provide protection against dissemination of COVID virus into the procedural environment.
That said, further studies would be needed to compare aerosolization rates and ranges between this type of system, a bag-mask system, and a closed-circuit system utilizing endotracheal intubation in order to compare COVID-related safety profiles of these various strategies for airway management. It is possible that these devices would lead to less viral dissemination. It is also possible (and easy to imagine) that they could increase the risk for respiratory pathogen transmission.
Long story short, this device looks like an excellent addition to the armamentarium of airway management strategies. As an anesthesiologist, I can think of several applications for this device that would be convenient and make my job easier by obviating the need for manual ventilation (which occupies two hands) or endotracheal intubation (with all of its unique risks). The duration of ECT and the common use of succinylcholine do indeed make this set of devices a welcome device in the ECT suite.
However, while this device may increase the ease of performing the necessary procedures, those same procedures most certainly can be performed safely/reliably with other commonly available tools. Thus, the utility of this set of airway devices is probably limited to enhancement of ergonomics and convenience but not to enhancement of patient safety. In other words, my first assessment is that this strategy for airway management during ECT could find widespread use if the relative cost of utilization is low. If purchase and/or maintenance of the required equipment comes at a substantial cost relative to existing equipment, the ultimate utility of this strategy will be limited.
As to the topical question of whether this alternative strategy for airway management decreases risk of periprocedural COVID-19 spread, further rigorous study would be needed to make any such claim. Given what we know about how these systems function, we certainly cannot say out of hand that they reduce this risk.
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ReplyDeleteVery cool device. There are many situations in the day to day practice of anesthesiology in which a hands-free mechanism for providing/maintaining airway patency would be useful and convenient. Naturally, in cases where muscle relaxants (like succinylcholine) are used, maintenance of a patent airway will not, in and of itself, maintain hemoglobin oxygen saturation. Fresh oxygen must still be entrained into the lower airway. Typically, this requires ventilation of the lungs, almost always using positive pressure to move air into the lungs. This usually means the use of a bag-valve mask device or placement of an endotracheal tube which is then connected to a ventilator. All forms of positive pressure ventilation create a risk of aerosolization of respiratory particles, thought to be a key point of risk for transmission of respiratory pathogens like COVID-19. Beyond that, positive pressure ventilation with a bag mask device typically occupies both of an anesthesiologist’s hands and endotracheal intubation carries with it its own set of risks and possible complications.
In situations where closed circuit positive pressure ventilation is not feasible (often in pediatric and ENT anesthesia), concentrated oxygen can be delivered via an open circuit into the upper airway. Passive diffusion of oxygen from areas of high concentration in the oro/naso-pharynx to areas of low concentration in the lungs allows for some replenishment of deoxygenated venous blood, and thus for longer apneic time before clinically significant desaturation events. This passive oxygenation of the blood can (if airway patency is maintained) significantly increase safe apneic time. The increase in safe apneic time that results is significant in the case of ECT performed under succinylcholine-induced muscle relaxation. The clinical duration of a single dose of succinylcholine is well matched to the duration of the ECT procedure itself. The period of time required for the procedure (and for recovery from a single dose of succinylcholine) is greater than average safe apneic time in the absence of passive oxygenation. But passive oxygenation can easily push the duration of desaturation-free apneic time beyond the expected duration of the procedure and the duration of action of succinylcholine, thus theoretically obviating the need for positive pressure ventilation (thereby reducing the risk of aerosolization which can contribute to the spread of respiratory pathogens like COVID-19).
What cannot be achieved with purely passive oxygenation is true ventilation. While oxygenation of blood can be achieved, the other major function of pulmonary respiration – the clearance of CO2 and subsequent maintenance of blood pH – will not result from truly passive oxygenation. Thus, passive oxygenation without ventilation is only sustainable for short periods before hypercarbia and acidosis set in. (continued in next response...)