Re: Inhaled anesthetic gas for severe bronchospasm at the emergency department

Dear Editor,

We read the article titled “Inhaled Anaesthetic Gas for Severe Bronchospasm at the Emergency Department” by Adi et al. with great interest [ ]. We would like to congratulate the authors for their meticulous management and excellently drafted manuscript. Using an anesthesia-conserving device (AEC) like AnaConDa™ (Sedana Medical, Sundbyberg, Sweden) for the management of refractory bronchospasm in the emergency department (ED) has added another dimension to its pre-existing uses. However, through this correspondence, we would like to highlight some unaddressed issues that the readers would be keen to know.

Firstly, the availability of AEC is likely to be an issue. The use of an anesthesia workstation can be an effective alternative for delivering inhalational anesthetics like sevoflurane as these are stationed in all institutes. By using the workstation, we can deliver the gases precisely instead of a syringe pump [ ]. Moreover, the exhaled and inhaled gases could have been measured more accurately along with monitoring of airway pressures and exhaled carbon dioxide which can guide treatment. Secondly, when the authors felt the requirement for anesthetic gases, they could have shifted the patient to the nearby post-anesthesia care unit (PACU) instead of managing such cases in the ED. The patients would have benefited from the easy availability of anesthesia workstations, monitoring and trained anesthesia staff. Thirdly, the authors haven’t mentioned anything regarding serial chest X-rays or computed tomography scans for monitoring the chest condition. Since hyperinflation is very common in patients with status asthmaticus and mechanical ventilation in a patient with refractory bronchospasm can be associated with increased risk of barotrauma, and volutrauma following high end-inspiratory pressure [ ]. Fourthly, there is no information regarding the rebound bronchospasm and how the sevoflurane infusion was tapered (rate and time period). Additionally, the authors have mentioned in case-2 that the patient developed hypotension (blood pressure-90/60) on increasing the sevoflurane dose. But the MAC value was kept at 0.5 (0.4–0.6), and hypotension at this MAC is unlikely. We feel that the hypotension might have been due to dynamic hyperinflation which can occur in such cases of obstructive lower airway pathologies though the authors do not mention an increase in auto-positive end-expiratory pressure (PEEP). In case-1, the authors mention a worsening intrinsic PEEP and air-trapping but there is no mention of the resulting changes in hemodynamic parameters. Hypotension is a possibility in these patients due to this dynamic hyperinflation and such success stories might trigger an indiscriminate use of this device in the ED, which can worsen patient outcomes if not rectified immediately. In the same case, they mentioned that the patient was maintained on inhaled sevoflurane for a total of 6 h in the ED before being admitted to the High Dependency Unit (HDU). But there is no mention of the course of the patient in HDU like tapering of sevoflurane, any tracheostomy plan or development of ARDS which can complicate pre-existing asthma, any other drug infusion like the intravenous anesthetic agent, sedation or muscle relaxant to achieve the target Richmond Agitation-Sedation Scale (−3 to −5) to maintain ventilator synchrony and decrease auto-PEEP.

Another important concern is the environmental impact of the use of sevoflurane. These cases are relatively common in the ED which is not well equipped to handle inhalational agents. There is generally no provision for scavenging systems and long-term exposure to these agents can be a health hazard for ED personnel. Hence, shifting them to PACU and administering sevoflurane through the anesthesia workstation and the closed circuit would be a better option as even low flows can be provided and scavenging can be done [ ].

To conclude, we feel the manuscript will be more interesting and clearer to the readers and students alike if the authors can throw some light on the above-mentioned issues.

Author contributions statement (CRedIT statement)

AKB and CRM: Conceptualization (lead); Methodology (lead); Writing – original draft (support); Writing – review and editing (equal). AG: Writing – original draft (Support), Investigation (lead), and writing – review and editing (support). RVR and RKK: Software and investigation (support), Writing- review and editing. CRM did the overall supervision of the whole study, and all authors had made a substantial contribution. All authors have read and agreed to the content of the final manuscript. [AKB: Amiya Kumar Barik, CRM: Chitta Ranjan Mohanty, AG: Anju Gupta, RVR: Rakesh Vadakkethil Radhakrishnan, RKK: Rajani Kant Kumar].

Consent to participate

Not needed.

Ethical approval

Not Applicable.

Source(s) of support

Nil

CRediT authorship contribution statement

Amiya Kumar Barik: Conceptualization, Formal analysis, Project administration, Resources, Software, Supervision, Validation, Visualization, Writing – original draft, Writing – review & editing. Chitta Ranjan Mohanty: Conceptualization, Data curation, Methodology, Resources, Software, Supervision, Validation, Visualization, Writing – original draft, Writing – review & editing. Anju Gupta: Conceptualization, Project administration, Resources, Software, Supervision, Validation, Visualization, Writing – original draft, Writing – review & editing. Rakesh Vadakkethil Radhakrishnan: Conceptualization, Resources, Software, Supervision, Validation, Visualization, Writing – original draft, Writing – review & editing. Rajani Kant Kumar: Formal analysis, Resources, Supervision, Validation, Visualization, Writing – original draft, Writing – review & editing.