Field Guide to ParaMagic

Medical Mnemonics// Post MI complications can be remembered using the mnemonic DARTH VADER.

Anyone that has spent some time learning about the physiology the body should have crossed the term acid-base balance. Our body is a system of checks and balances with everything we do and one of the major systems is to make sure out pH in the blood stays between 7.35 - 7.45.

For those who don’t understand pH or acids and bases check out this link for a quick idea:

Crash Course

There are four major lab values to look for to understand the what we are discussing here and I want you to have them prior, so I won’t spend time talking about that much. You should be able to look and know what is high and what is low from this.

There are two major groupings that will affect the acid base balance and those are the metabolic (kidneys) and respiratory (lungs). With that being said, you will find four categories for these to be broken into as well:

Respiratory Acidosis

First thing you need to know is that when you disrupt the oxygen supply to the body, you create CO2 alkyl ion which then becomes a carbonic acid. There are a lot of causes but the major ones include: CVA, tumour, infection (encephalitis), haemorrhage, narcotics and sedatives.

Treat these patients with clearing obstructions from the airway, giving supplemental oxygen and treating the underlying cause the best you can.

You may find the body will increase the bodies Bicarb levels to offset the increased levels of CO2. Pts with COPD who naturally have a higher Bicarb levels after a period of time to manage the constant increase in CO2 in the blood.

Respiratory Alkalosis

My favorite story to tell is the young college student who went to the walk-in one day and had a heart rate of 146 bpm and was hyperventilating. The kid was having a panic attack, but then freaked himself out more when he began having carpal pedal spasms, causing more hyperventilating. We (EMS crew) found him on the floor crying, “am I going to die?”

This story is one of a pt who pushed off way too much CO2 and caused the pH to go up. There are many ways for this to happen thought (CVA, ICH, psychogenic, Thyrotoxicosis

Pregnancy, Sepsis, DT, anxiety, pain, DKA and aspirin OD), and again we must treat the underlying cause for this. Usually this will mean coaching the pt down when they are breathing.

The checks and balance system of the metabolic system will play a role and you will find the body will keep some of those hydrogen ions trapped in the body, so you can keep the pH in normal range.

Metabolic Acidosis

The major organ to play a role with this is the kidneys. This is where the excess anions are pushed to the bladder and then excreted out during urination. So, imagine a pt on dialysis that has not received treatment for a week or two. Do you think their pH will be lower?

Here is a good acronym to allow you to know for causes for metabolic acidosis:

M            Methanol (formic acid), metformin

U            Uraemia (including aminoglycosides)

R            Renal failure (Uric acid)

K            Ketoacidosis (alcohol, diabetes (acute), starvation)

L            Lactic acidosis

E            Ethanol

S            Salicylates

E            Ethylene glycol (glycolic acid)

P            Paraldehyde, propylene glycol

T            Toluene

I             Iron, isoniazid

C            Cyanide and carbon monoxide

Treatment for these patients will be based on what they are currently dealing with. Remember that if a pt is having metabolic acidosis, you might see an increase respiratory drive from the pts at this time to balance the acid.

Metabolic Alkalosis

Increase the pH in the blood and what do you get? If you said a turtle wearing a jumpsuit, than you are wrong! If you said Metabolic Alkalosis, then you read the title right.

Whether it is a loss of acid or increase in alkali in the body, you might have a higher pH. The major thing to remember is our lovely formula of acid/base balance. Bicarb might be high or you might have vomitted all day and decreased your Hydron ions that way. Either way the increase pH will cause a variety of problems in the body. You might find yourself dizzy or light headed. Chest pain has been known to come with alkalosis. And then anxiety came sometimes take part in the action.

Once again, there is a massive list of things to know and I don’t have a textbook, so I’ll share some key points you might like to research on your own or I can find some material later if you request. This is a quick bullet point showing  list of ways you may lose to extra anions:

G          GIT excess acid loss

Vomit (and pyloric stenosis)

NGT drainage

Diarrhoea

Ileostomy

Dehydration

R          Renal excess acid loss

Bartter’s

Gitelman’s

Diuretics (Loss of H+, K+, Cl-)

O          Overdose of base

Antacid OD, Laxative, Milk-alkali syndrome

Massive Hartmann’s transfusion

Iatrogenic use of HCO3

E           Endocrine

Cushing

Steroid excess

Hyperaldosteronism

Extra sources:

This is is a entire lecture on the subject and it a good 50 minutes long. I would recommend watching the first bit of it at least and then putting it on times 2 speed through it all.

Major source for material was from: Lifeinthefastlane

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Today I taught myself about reading EKG’s and where they actually line up with things going on in the heart with regards to MIs. Basically you have 3 coronary arteries that get occluded in most MIs: Left Anterior Descending (LAD), Left CircumfleX (LCX), and Right Coronary Artery (RCA). LAD feeds the anterior heart and the septum. LCX feeds the lateral and some posterior heart. RCA feeds the right ventricle and some posterior heart, as wells as the SA node in 60% of people.

Now EKGs are confusing and complicated, but it gets easier if you remember where they measure relative to the anatomy. This little diagram helps me get started:

I’ve overlaid the heart over this in the diagram up top. Now remember, those arrows are vectors which is reflected in an EKG read by the upstrokes and downstrokes of the read. (I’m oversimplifying things, but physics makes my brain hurt, and this has worked for me so far.) Practically, what it means is that if the arrow is pointing towards the damage you get ST elevations. For example, in an inferior infarct, you get ST elevations in II, III and aVF, which point towards the inferior part of the heart.

You also have leads V1-V6 which are arranged like so:

(Image from wikipedia)

Notice their vectors point anteriorly. So an anterior infarct shows up at ST elevations in some or all of V1-V6. Meanwhile a posterior infarct will show up as ST depression in V1-V3 which point away from the posterior part of the heart.

To take it one step further you can figure out which artery is blocked. But that’s just a matter of knowing the blood supply, which is basically just what’s nearby. When I’m trying to figure it out on a test, sometimes I draw out this 5 second diagram (aka artistic masterpiece):

Cricoid pressure, commonly called the Sellick maneuver,1 has many uses in emergency airway management. Although simple to perform, the Sellick maneuver requires explanation:

Locate the cricoid cartilage, larynx, trachea, and the hyoid bone by palpation so that pressure is applied to the right structure. Hold the cricoid cartilage between the thumb and the middle finger. Place the index finger on the cricoid cartilage. Push the cricoid cartilage backward against the spine. Push with about 9 pounds of pressure (40 Newtons). Use common sense. If the patient is at risk for a cervical spine fracture, use less pressure.

The primary purpose of this pressure is to collapse the esophagus between the cricoid cartilage and the spine. This prevents regurgitation of gastric contents. a It is not intended to prevent vomiting. Patients who vomit have active gag reflexes. If you are applying cricoid pressure and the patient vomits, let go and let the patient cough out the vomitus. Log roll the patient to ease this process and to suck out the vomitus with a suction tip.

During orotracheal intubation, the person who performs cricoid pressure must maintain this pressure from the onset of the procedure until the ET tube has been inserted and tested for correct placement (esophageal intubation detector [EID], CO2 detection, breath sounds, etc.) and the cuff of the ET tube has been inflated.

One can press too hard. If the intubator is having difficulty getting the endotracheal tube introducer (ETI) or the ET tube into the trachea, you may be obstructing the larynx with too much pressure. Ease up the pressure momentarily and let the tube in.

If the intubator is having difficulty visualizing the larynx, move the cricoid cartilage from side to side. If the intubator is looking at the esophagus, it will not move.

If the intubator inserts the laryngoscope blade too deeply, you will feel the larynx being lifted by the blade. If this occurs, inform him or her. As the blade backs out, you will feel the larynx fall back when it reaches its correct position.

If the intubator uses an ETI, you will feel the tip of it run over the tracheal rings. This feels like a washboard sensation. If you feel this effect, it is positive confirmation of correct placement of the ETI. Inform the intubator.