Re: the twitter posts... I didn't read that as condemnation of Dr. Harris. I read it as a professional acknowledgment of the risks that he had no choice in taking.Originally Posted by bigdave
My wife has been put under more times then I can remember when she had cancer and I know how methodical and monitored it usually is. That just wasn't an option here.
I think it just shows how they judged panic to be by far the biggest risk. The doses mentioned here are well into the dissociative regime, deep into "k-hole" territory, and likely close to unconsciousness. Not just something to take off the edge a bit. It's a substantial risk, but so was the full face mask with no backup plan if it came loose. I'm glad and grateful that it all worked out in the end, except, of course, for the one rescue diver who lost his life.
In my job we frequently use ketamine combined with a benzodiazepine (Dr. Harris used alprazolam, we use midazolam) and atropine (to decrease salivation which is a side effect of ketamine) for procedural sedation and for sedation during critical care transports both air and ground. It's a great combination; the patient continues to breathe and maintain their own airway, but is passive, dissociated, unaware, pain-free, and has no recall of the incident. This combination has a great safety profile and minimal if any effects on hemodynamics or vital signs, and can be given IV or IM.
But in our case the patient is on EKG, oxygen saturation, and blood pressure monitors and has a critical care RN and paramedic at bedside, and in the hospital also a respiratory therapist and a physician immediately available. There is suction, oxygen, and resuscitation equipment and medications within arms reach. They don't get left alone even for a second; eyes-on the whole time. To sedate someone and then swim them through a flooded cave is well off the edge of the map into the "There be Dragons" area. To do it once successfully is an amazing accomplishment. To do it 13 times is almost beyond comprehension.
Last edited by MORGAN; 08-01-2018 at 09:45 AM.
What he said!!! These kids are off the bell curve for guidelines for sedation due to illness, cold, malnutrition, not to mention DROWNING. "Amazing Accomplishment" by absolute Rock Stars!
Appreciate the insight from a pro Morgan, thats fascinating. To put things in perspective based on a bit of internet amateur sleuthing... dosages measure in "mg/kg", milligram of drug per kilogram of body weight, so dosage compensating for body weight. Morgan would know this better but based and dosages it sounds like it was delivered IM (Intramuscular) rather than IV (Intravenous), which is appears to last longer, is less risky and possibly (?) easier for the non-trained divers to administer en-route (would like to hear Morgans thoughts on that).
Dose given to kids (from tweet): 5 mg/kg initial, 2.5 mg/kg top-up
From Erowid Ketamine FAQ: https://erowid.org/chemicals/ketamin...mine_faq.shtml
Psychedelic effects begin (IM): .3 - .4 mg/kg
Fully anesthetic dose begin (IM): 1.0 mg/kg
LD50 (Lethal dose in 50% of test subjects) (IM): 77 mg/kg
From Epocrates: https://online.epocrates.com/drugs/1...ne/Peds-Dosing
Pediatric IM dose: "2-5 mg/kg IM x1; Max: 6 mg/kg/dose; Info: onset 3-10min, duration 15-90min; may give 2-4 mg/kg IM x1 10min after initial dose; consider adjuvant antisialagogue and benzodiazepine; IV route preferred"
Regarding safety, overdose safety of drugs (is? was?) often represented in the "Therapeutic Index", which is the ratio of LD50:ED50 (Lethal Dose in 50% of test subjects compared to Effective Does in 50%...). Based on the above it sounds like the therapeutic index of Ketamine in anesthetic dosages is in the 20-35 range (?)... safer than alcohol or cocaine which is in the 10-15 range but compared to morphine at 70. Aspirin is around 4, yeah, not so safe by that metric.
I asked a uhh friend who has done Ketamine recreationally at a psychedelic/sub-anesthetic dosage, and they described the dissociative effects as being akin to becoming aware of his body as being simply an unrelated physical object, moving around was akin to being a machine operator pulling levers and the body would move accordingly, so the body became something like a slow moving car with the "ego" or self as the driver. But that is merely a stop on the route to being fully unconscious of the body which it sounds like these kids were WELL into. So yah, the kids were in the k-hole.
Take everything posted above with a huge grain of salt, Morgan would love to hear any of your thoughts on the matter. Big respect to the guys who effectively did 13 body recoveries in very harsh conditions while, largely untrained in the medical field, keeping people dosed and alive under anesthetic with 100% success...damn.
Rob
I am an anesthesiologist. I'm not second guessing what they did, they did a fantastic job. Having said that, their dosing regimen was quite aggressive. As an example, if we have a mentally challenged patient that won't let us start an IV, I will give 1 mg/kg intramuscularly to get them to calm down enough to let us start the IV. This dose usually makes them quite relaxed, and sometimes even drowsy. Ketamine will USUALLY allow the patient to maintain an airway, but not always. Pt's can still obstruct and/or become apneic with those doses of ketamine. In an operating room, an obstructed airway is easy to fix, but swimming through a dark cave... not so much. I'm super happy it all turned out okay, but if I had been the one shouldering that responsibility, I'm not sure that's the way I would've done it.
Most anesthesiologists are risk-averse, and Harry is no exception. It was an incredibly courageous decision. Imagine the outcry if even one of those kids had drowned during the exit.
It is interesting to speculate on what might have happened had this incident occurred in the USA with its medicolegal climate. I suspect things might have turned out very differently.
This incident really does add new knowledge. Anecdotal evidence is typically denigrated, but 13 consecutive identical anecdotes with the same outcome becomes pretty convincing.
Andy
I can remember two points re ketamine from my anaesthetics attachment as a medical student back in the mid to late 1970's in the UK
1. Drug of choice if you can not guarantee access to airway. Taught that was used during Moor Gate tube disaster when some amputations required to free casualties where no access to airway.
2. great for children as they do not as tend to to be as distressed by hallucinations during recovery as do adults. Children tend not to mind waking to see elephants flying around the recovery room, adults can become a little distressed.
Isn't that what Good Samaritan laws are for?
It's complicated. Some states actually have a duty to rescue. Even when no such requirement exists, medical professionals do not always have an icon clad protection from Good Samaritan laws. They have a lot more training and experience so they can be held to a higher standard of care.
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