Respondents' comments

- gone through simulation sessions in chamber for courses, but can’t recall any actual arrests in chamber requiring defibrillation. Have had arrests but from other causes-profound anaemia, probable CAGE”

-  “none in last 25 years (living memory), no records/memories prior to that time”

-  mention of an experiment in the late 1990s where a hyperbaric physician colleague defibrillated a side of beef in the multiplace chamber at Fremantle Hospital at 2 ATA and then lit a candle, without any adverse outcome. The respondent witnessed the event from outside the chamber. 

- “our unit has just received access to our first ever hyperbaric compatible monitor/defibrillators in Nov 2021. We are yet to establish any policy on their use yet”

- “no doubt there is a process, as the chamber tech I am only aware of my procedure”

3 Is there an EP for monoplace chambers?

4 If you answered “Yes” to Q 3+/-4 do your EPs differ for different treatment tables or depths/pressures?

5 If there were cases of cardiac arrest requiring defibrillation in your unit, what was the outcome for the patients?

6 In your unit, do you have the capability for defibrillation with the adhesive pads on the patient, the cables fed through the chamber hull and the defibrillator and operator placed outside the chamber (i.e. the ability to defibrillate under pressure)?

7 Did you have any cases of cardiac arrest during HBOT when it was decided to remain at pressure, continue CPR or manage with chest compressions only?

8 Do you regularly run “pulseless diver” or “pulseless hyperbaric patient” cardiac arrest drills in your unit?

- probably not often enough”
- ”we do run them semi-regularly and have practiced them with and without the sling (high BMI patients)”
- “ would run drills every 2-3 years, but more with COVID and recent Monoplace development”

9 Do you think there should be a standardised hyperbaric ACLS-like protocol for cardiac arrest occurring under pressure applicable in all Australasian HMUs?

-  “would be very helpful” 
-  “too many variables between units-e.g. physical chamber size and design, ability to lock-in additional staff in a hurry, staffing levels and skill sets etc. Knowing the various units around Australasia, no “one-size-fits-all” solution is likely to be practical (person with long experience >25y, Royal Hobart)”
-  “only if locally derived protocols are absent or inadequate”
-  “high pressure, low frequency and short “time to think” events, especially with a relatively fixed immediate intervention requirement (i.e. cardiac arrest) would only benefit by an accepted and clear treatment protocol/algorithm”
-  “ it would depend entirely on on the circumstances of the CA as to what to do (eg PEA secondary to tension pneumothorax would potentially require decompression of the pneumothorax first” 
-  “would be very interested in any such standard”
-  “would be nice, but I think impractical as physicians tend to manage things as per their experience. Even treatment tables vary from place to place. I think a guideline with bespoke alterations depending on unit capabilities/experience would be most likely”

10 If you are happy to be contacted for follow-up or further discussion about this topic, please enter your name and contact details for your HMU below. Email me on …@…if you would like to share further details or have additional comments.

10 respondents left their details and some offered to share their EPs, 4 skipped this question.

The HMUs at Fiona Stanley Hospital, Murdoch, WA and Christchurch, New Zealand, shared more detail and their EPs