This is a bit of Medical MacGyverism that I have tried in the past and failed, but got right recently.
Here is the case – could be any day in our shop…
The ambulance have arrived in ED with a young man who was “found down” on the sidewalk with no witnesses to the preceding events. The handover is: “he’s just paraletic…”
En route he has received oxygen, IV fluids and some jaw-lift to support his airway. There is a bit of vomitus on his shirt but no cough or tachypnoea.
Obs on arrival: GCS = 3, no response to pain, no localising signs
BP = 110/50, HR 65/min SpO2 = 98% on 6L/min and RR = 14. His finger prick BSL is 10 (180 for the Americans..)
A line is placed and a VBG shows a mild respiratory acidosis with pCO2 = 50, otherwise normal numbers.
Just as we are contemplating the next move and searching for any overt injuries / scalp lacerations etc our pavement paedestrian starts to vomit and gag, he is suctioned aggressively and is tolerating a Yankauer in the upper airway a little too easily.
This is looking like he is requiring a definitive airway to protect his lungs and maintain oxygenation – we still don’t have a clue as to why he is unconscious. Sure, it is Broome – therefore alcohol is top of the list… however, it would be folly to narrow the diagnostic curtains so early.
The Police arrive at this minute to try and assist with identification and they report witnesses did see a bit of shadow-boxing and argumentation occurring an hour before he was “discovered” on the ground. Maybe trauma is on the cards?
OK – we need to exclude a brain injury, we need a CT. He needs a tube… so we do a brain-sparing intubation (see Clinical Case 135). He passes through the doughnut of death unharmed (aside from a few milliSeverts). And….. the CT is …[drum roll] … completely normal.
So what is going on? Wouldn’t it be great to know his alcohol levels? Yes, it would. But we have no way of measuring plasma alcohol levels in the bush and he is smoking a “blue cigar” – so how can we get a breath analysis done?
well after a few failed attempts to do this over the years I think I have cracked it. I am not sure if this is described elsewhere, and I apologise if I have stolen / plagiarised this from others..
Here is how we do it step-by-step…
- Put the FiO2 up to 100% for a few minutes to give adequate reserve.
- Recruit 2 friends to help – this is a 3-person job
- Get the trusty breath-alcohol analyser (or steal the Police’s if you don’t have one in your ED) and attach the mouthpiece.
- Loosen the tube connector so that you can disconnect quickly. You need to disconnect at the tube connector, not at the 3/4inch circuit connection.
- Team member 2 can now give a big inspiratory breath (use a self inflating bag or hold the vent / circuit manually to fill the lungs
- Quickly disconnect the tube connector and put your thumb over the end to prevent the breath escaping.
- Count 1-2-3… place the mouthpiece over the end of the tube as best you can to get a seal.
- Ask team member ‘number 3’ to give a lateral chest squeeze to empty out as much of the residual volume as possible to allow the device to register its automatic volume to perform analysis.
- reconnect the tube once you have your breath , make sure it is tight and your end-tidal CO2 is reading again.
- Bingo – you have a breath-alcohol level on an unconscious / ventilated patient in the bush.
In our patient we got a reading of 0.42% – which is rather high, even for Broome. So now we need to decide what we should do with this information. Be very careful. There is a big risk of “confirmation bias” and “early diagnostic closure” in this setting.
My rule: the sicker the patient, the broader that you need to think. Keep all the cards on the table until they show improvement.
In this case there is a reasonable predictable course we might expect if this is really “just the grog”. Any deviation from that course, unexpected results, change in status should make us reconsider our position.
Hope that makes sense.
Let me know if you have a better way to do this, or have a protocol to follow for this sort of patient.