EMS Protocol of the Week - Smoke Inhalation (Adult and Pediatric) and Cyanide Exposure (Adult and Pediatric)

The NYC prehospital approaches to smoke inhalation and cyanide exposure are nearly identical, so it’s worth knocking them both out at once. Both protocols start with ABCs and burn management, and both then focus on the administration of cyanide toxicity kits for post-exposure patients who are symptomatic. You can refer to the PDFs directly for advice on dosing and administration considerations (remember: hydroxocobalaminBEFORE sodium thiosulfate to avoid medication inactivation!). Otherwise, note that prior to administering the cyanide toxicity kit is the ONLY instance in these protocols where paramedics are trained and ordered to draw blood (for pre-medication cyanide levels). 

The key difference in the protocol for cyanide exposure is the early recognition of a possible MCI scenario, which would require a Class Order for widespread medication orders that would then be dispatched through our OLMC line. We touched on this months ago with the WMD protocol and the use of nerve agent antidotes.

Scary stuff, but always better to be aware ahead of time! Want to get even MORE ahead? Check out www.nycremsco.org or the protocol binder to stay on top of it all!

Dave

POTD: Digoxin toxicity

Many of our patients are on digoxin, a potentially scary drug. Today we’re going to discuss what digoxin toxicity looks like, how to approach acute v. chronic toxicity, and digiFab/digiBind.

How does digoxin work?

1. Inhibits cardiac Na/K antiporter → increased intracellular Na, decreased intracellular K

   1. Decreased intracellular K →  HYPERKALEMIA in dig overdose

2. Increased intracellular Na → increased intracellular Ca

3. Increased Ca →  INOTROPY

4. Increased inotropy → reflex INCREASED VAGAL TONE

   1. In afib, this decreases conduction rate through AV node → slowed ventricular rate

Some pharmacology

• Oral bioavailability = 40-90% 

• Onset of action 2-6 hours after ingestion 

• CANNOT be removed via hemodialysis

• Renally excreted

• Things that INCREASE digoxin levels:

  • Amiodarone, carvedilol, ranolazine, ticagrelor

  • Verapamil, tacrolimus, cyclosporine 

  • Macrolides (Azithromycin)

  • Azoles

• Things that DECREASE digoxin levels:

  • Carbamazepine, fosphytoin, phenobarbital

  • Rifampin

Digoxin toxicity: Acute or Chronic

ACUTE - usually starts with GI sxs, and then later neuro sxs

CHRONIC - insidious onset neuro sxs

• Precipitating factors:

  • Any AKI causes accumulation since digoxin is renally excreted

  • Drug interactions that INCREASE digoxin levels (above)

  • Tissue sensitivity to digoxin increased by: Hypo-K, hypo-Mg, hyper-Ca, MI, hypoxemia

Symptoms:

• Arrhythmias:

  • Sinus bradycardia, high degree AV block

  • SVTs with AV block are CLASSIC

    • Afib with slow ventricular rate

    • Afib with junctional rhythm

    • Focal atrial tach with AV block

  • Junctional tachycardia

  • Ventricular arrhythmias usually in CHRONIC toxicity

    • Bidirectional v-tach strongly suggests digoxin

• GI sxs: nausea, vomiting, abd pain, diarrhea

• Neuro sxs: delirium, fatigue, visual changes (change in color perception, blurry vision, photophobia, blindness)

  • Rarely seizures

Some EKGs attached.

“Salvador dali mustache” = scooped ST segment with ST depression, flat/inverted T wave +/- prominent U wave, short QT

Checking digoxin levels:

• PO digoxin requires 6+ hours to distribute into tissues 

• ONLY POST-DISTRIBUTION levels actually reflect severity of intoxication

  • Used to calculate antiserum dose

• ACUTE intox: check baseline digoxin then repeat another in 6 hours

• CHRONIC intox: one digoxin level is fine assuming it was >6 hours after last dose

How much is too much?

• Normal/therapeutic is 0.5-2 ng/ml

• Scary levels:

  • ACUTE: > 10 ng/ml

  • CHRONIC: >4 ng/ml

• However - serum digoxin doesn’t actually correlate that much with tissue levels or cynical toxicity 

• After getting antidote, levels don’t mean anything

The antidote: digoxin specific antibody fragments (DSFab)

• Indications:

  • Significant arrhythmias or HD instability

  • K > 5-5.5 if it’s caused by digoxin

• Softer indications:

  • Acute ingestion > 10 mg

  • Moderate-severe GI sxs

  • Serum digoxin > 10-12 

  • Renal failure

  • AMS

• Should consult toxicologist or poison control if not sure 

  • Poison control: 1-800-222-1222

• Digibind or digifab available (2 diff brands)

  • Comes in vials of 40 mg antibody fragments, which neutralize 0.5 mg of digoxin

• Dosage:

  • Chronic poisoning: (dig level x wt in kg) / 100, can start lower initially

  • Acute ingestion of known dose: (mg digoxin ingested) x 1.6

  • Acute toxicity unknown levels: 5 vials (HD stable) or 10 vials (unstable)

  • Chronic toxicity unknown levels: 3-6 vials and reeval

  • Or you can use MDCalc

The most important thing about digoxin toxicity is to recognize it!! Hopefully this helps!

POTD: Cordis placement

Here is another addition to our video series. Today we go through how to place a cordis. For those who are unfamiliar with it, this is basically a fat central line that is primarily used for rapid infusion of fluids or blood. It only has a single lumen.

The trialysis lumen is actually larger than the cordis lumen, but the cordis is way faster and easier to place since there are less steps and less separate parts, so this makes to place for crashing patients who just need large bore access and not multiple ports. (Of note - oftentimes 2 large bore peripheral IVs in the AC is FINE for resuscitation. But you might need a crash cordis if it's taking too long to place the peripherals.)

To compare:

Standard triple lumen central line = 7 french

Trialysis catheter = 13 french 

Cordis = 6 french or 9 french

We have 2 size cordis kits, 6 french and 9 french. The 6 french is actually the size you use for TVP. Clinically it makes more sense to place a 9 french if you need large bore access, but just know that we have both sizes in resus. 

Of note, the 9 fr kit has the cooler blue syringe that allows you to place the wire through the syringe, reducing another step in the procedure. 9 fr kit also has the wire holder, which makes threading the wire easier. 

So in summary, if you have a patient bleeding out on to the floor, please reach for the 9 fr cordis kit since it is A) larger, and B) has better things inside of it, imo. 

Here is the video:

https://youtu.be/Ls5TdDg9eK0

Enjoy!