Anaesthetic catastrophe (almost)

Re: Anaesthetic catastrophe (almost)

patrick murphy — Fri, 29 Jun 2012 15:44:08 GMT

I had a midazolam pre-mix once, and I remembering thinking how useless it was until takeoff. wow it sure does work. my patients don't seem to go anywhere on it.just my experience

Re: Anaesthetic catastrophe (almost)

patrick murphy — Fri, 29 Jun 2012 15:35:59 GMT

for sure before

Re: Anaesthetic catastrophe (almost)

Rajat — Wed, 27 Jun 2012 20:25:29 GMT

[quote user="James Laidlaw"] Small world![/quote]

Indeed! Think I remember (vaguely) Si talking about that trip to NZ now that you mention it...

Re: Anaesthetic catastrophe (almost)

James Laidlaw — Wed, 27 Jun 2012 19:04:43 GMT

Toby was mates with post and si who saw practice with me in NZ when I was in my first job, then I locummed with him in Burton on Trent a few years back. Small world!

Re: Anaesthetic catastrophe (almost)

Rajat — Wed, 27 Jun 2012 18:32:58 GMT

No worries, hope tomorrow is a better day and your drink soothes your nerves..btw noticed you're mates with Beer/Toby on FB - how do you know them?! I lived with them in final year!

Re: Anaesthetic catastrophe (almost)

James Laidlaw — Wed, 27 Jun 2012 18:24:45 GMT

Thanks Raj, and all.

Has been one of those days - going to mull it all over once home and with drink in hand, then decide on plan to investigate tomorrow!

30 minutes to go though - not crossing my fingers that the day is over yet the way things have gone...!

Re: Anaesthetic catastrophe (almost)

Alet Engelbrecht — Wed, 27 Jun 2012 18:08:23 GMT

[quote user="Jo Jones"]Just prior to induction for the last GA I had my anaesthetist was quizzing me about veterinary anaesthesia. He waited until after he'd given me an i/v midazolam premed though.... I'm not sure my answers were very useful![/quote]

Lol, same happened here! Very keen to here about our protocols as he was pushing midazolam, I am sure I was already drooling! When I woke up, one of the nurses in recovery asked me about her Westie with skin problems!

Re: Anaesthetic catastrophe (almost)

Rajat — Wed, 27 Jun 2012 17:21:45 GMT

Hi Baby cardiologist here so go gently with me

Interesting, so it sounds like after intubation, the chest wall and bag was moving, but the CO2 registered apnoea... unusual, if correct- but one of the differentials as you know for low CO2/absent CO2 readings is poor/nil cardiac output. This is because with absent/much reduced perfusion -->no CO2 delivered from extremities to lungs-->very low or zero CO2 transferred from blood-lungs and hence the low ET CO2. In fact a rapid drop in CO2 in many cases indicates impending cardiorespiratory arrest, and a return in ETCO2 post cardiac arrest is indicative of return of spontaneous circulation. It is a fantastic tool for many reasons (can you tell I love my capnographs?!!)

Also , as you know, the heart can keep beating with very poor output (electromechanical dissociation or pulseless electrical activity) so its really good you guys felt for the pulse and found it to be weak. You say the second machine showed absent cardiac tracing, I assume this was from the ECG leads (sorry stupid q but thought id clarify) ?Any chance you had a trace from the first machine?

If I was to put money on what happened, it is that the propofol caused severe cardio respiratory depression to the point where perfusion was severely impaired hence the absent CO2 tracing and (assuming). Cardiorespiratory arrest followed. It only takes 10 seconds of absent cardiac activity to cause loss of consciousness in people/dogs. So assume some cerebral hypoxia/myocardial hypoxia and so on. You and your teams quick thinking saved the dogs life!

Tough to know why this happened, but my only suggestion would be to give Propofol much more slowly than 20-30 seconds. The vein to brain time is 2-3 minutes if I remember correctly (and for the life of me cannot find the reference!), and giving it too rapidly is the number one cause of complications as it causes much more hypotension, myocardial depression and respiratory depression/arrest this way, which obviously isn't good.

My general technique for propofol induction (if you are interested!) is to give 1/4th of the calculated dose every 30 seconds while providing flow by oxygen. If the patient gets excited or is very anxious, the initial 1/4th can be given quicker. Some patients I intubate on 2mg/kg others take 5mg/kg. For any ASAIII or higher patient, I either use Alfaxan/midaz ketamine (if no contraindications to ketamine) or fentanyl/midaz//fentanyl/diazepam. For a healthy JRT underoging castration I would not hesitate to repeat propofol induction but if you are nervous (I can imagine) about repeat GA try one of the other techniques. Alternatively, co induction with diazepam/midazolam/ketamine/lidocaine all prior to Propofol can reduce the dose needed by 50%. And worth remembering propofol is given to effect, to check patient after every 1/4 dose and that for 'intubatability' and that not all patients need the 4mg/kg dose.

Best wishes

Raj

Re: Anaesthetic catastrophe (almost)

Hannah Wynne Richards — Wed, 27 Jun 2012 16:23:59 GMT

Any cardiologists around?

Wynne

Re: Anaesthetic catastrophe (almost)

James Laidlaw — Wed, 27 Jun 2012 16:07:13 GMT

Sorry for the mis-use of a term, but when I've seen agonal breathing/cheyene-stokes - it LOOKS like this breath looked, I'm sure all vets know what I mean by this, but apologies if I have assumed that wrong.

Also, he was breathing fine the whole time until I noted the cardiac problems.

Re: Anaesthetic catastrophe (almost)

Jo Cobbett — Wed, 27 Jun 2012 15:59:09 GMT

[quote user="Utlendigur"]

[quote user="patrick murphy"]

[/quote]

Was that before or after your GA??

[/quote]

Just prior to induction for the last GA I had my anaesthetist was quizzing me about veterinary anaesthesia. He waited until after he'd given me an i/v midazolam premed though.... I'm not sure my answers were very useful!

Re: Anaesthetic catastrophe (almost)

Utlendigur — Wed, 27 Jun 2012 15:56:46 GMT

[quote user="patrick murphy"]

[/quote]

Was that before or after your GA??

Re: Anaesthetic catastrophe (almost)

patrick murphy — Wed, 27 Jun 2012 15:46:23 GMT

I once asked my may own anaesthetist if he got propofol apnea, and he said that not only did they get it in people, but they passively/actively encouraged it as it gave them time to get their gear all set up. he was completely unfazed by it, but then I am sure that they have a lot more control and kit and staff.

Re: Anaesthetic catastrophe (almost)

Bob Russell — Wed, 27 Jun 2012 15:33:44 GMT

Not good to tell a client that the last breaths are agonal!

Cheyne-Stokes respiration is a lot more comforting for owners, if not technically correct!

Post-induction apnoea is not unusual with propofol. Perhaps this was true Cheyne-Stokes here as pO2 and CO2 would be changing.

Re: Anaesthetic catastrophe (almost)

Thomas Johnson — Wed, 27 Jun 2012 15:25:22 GMT

[quote user="James Laidlaw"]

then did one breath that looked like Cheyene-stokes

[/quote]

Very distressing, not sure what the cause is likely to be, other than that it's a staff pet.

On a slightly different topic, you can't have one breath that looks like Cheyne-Stokes, from wikipedia:

"Cheyne-Stokes respiration ( /ˈtʃeɪnˈstoʊks/) is an abnormal pattern of breathing characterized by progressively deeper and sometimes faster breathing, followed by a gradual decrease that results in a temporary stop in breathing called an apnea. The pattern repeats, with each cycle usually taking 30 seconds to 2 minutes.^[1] It is an oscillation of ventilation between apnea and hyperpnea with a crescendo-diminuendo pattern, and is associated with changing serum partial pressures of oxygen and carbon dioxide."

What most people mean when they say Cheyne-Stokes breathing is agonal respiration.

Re: Anaesthetic catastrophe (almost)

James Laidlaw — Wed, 27 Jun 2012 14:57:33 GMT

Nope! I hadn't even started and was on the verge of running for the crash kit adrenaline when the heart started again. He never stopped breathing until the heart sopped, then did one breath that looked like Cheyene-stokes, at which point the nurse initiated IPPV I ran for my better stethoscope and by the time I listened again the heart started clearly, loudly and rapidly before resuming normal operation. No more gas, we just woke him up. Heart sounds probably absent for no more than 30-60 seconds (seemed like forever!) but pupils were dilated according to the nurse and the gasping breath looked for all intents and purposes like the end. I'm not so sure it's respiratory, more cardiac to me as that's what stopped. I did give the propofol over 20-30 seconds and flushed through with saline via catheter, but he induced smoothly and was breathing the whole time. Only cases I've ever seen with propofol problems appeared to be gone before the needle was withdrawn.

Re: Anaesthetic catastrophe (almost)

Alet Engelbrecht — Wed, 27 Jun 2012 14:04:56 GMT

[quote user="Utlendigur"]Staff patient - always trouble! [/quote]

Definitely! Same thing happened years ago with one of the receptionists' bitch that came in for spaying. Op wasn't done and receptionist and all vets that were involved at the time now too terrified to touch her.

Saying that - I've had a cat that just did not breath spontaneously under ga when placed in dorsal recumbency. Luckily, I had an extremely competent and experienced nurse who did not panic, informed me of the situation, continued IPPV whilst ensuring that one of the other vets were aware and immediately available to help if required. We had a ventilator, but the procedure was short and we finished with IPPV only. Not my neatest sutures...

After another similar incident, I asked an anaesthesiologist friend what I could do differently or where I went wrong. Advice - these things happen occasionally and sometimes there is a reason and sometimes not. The biggest problem is that the owner (understandably) wants to avoid all future ga's, but that is not the answer either. One has to be careful always and it sounds like you were very cautious, James. Did you finish the procedure?

Re: Anaesthetic catastrophe (almost)

Utlendigur — Wed, 27 Jun 2012 13:27:38 GMT

[quote user="James Laidlaw"]Had a bit of a shock today with a
staff patient.[/quote]

Staff patient - always trouble!

Could it have been just respiratory depression from the propofol? I tend to give it fairly slowly to effect (usually end up giving about 3ml/10kg) but if it's a wriggly dog/cat and I just have to whack it in I've noticed a few need ventilating for a minute or two. It sounds more respiratory than cardiac given the heart came back fairly quickly with ventilation and CRT was 1s - xray chest? bloods?

Re: Anaesthetic catastrophe (almost)

James Laidlaw — Wed, 27 Jun 2012 12:56:21 GMT

Yeah, tube definitely in, could feel breath on intubation and bag moving with chest movements. Can't think of any reason why he'd have a diaphragmatic rupture - no history of trauma - but will keep it in the ideas bank!

Re: Anaesthetic catastrophe (almost)

Hannah Wynne Richards — Wed, 27 Jun 2012 12:35:07 GMT

If visibly breathing but no capnograph registering-was the endo in the oesophagus? Sorry for stating the obvious Alternatively possible ruptured diaphragm so although visible breathing efforts unable to get oxygen in once placed on his back

Wynne

Re: Anaesthetic catastrophe (almost)

James Laidlaw — Wed, 27 Jun 2012 11:59:57 GMT

Sorry about the paragraphing - computer is being stupid...