Acid-Base balance made simple.

pH is a measurement of acidity. It just measures how acidic something is. When referencing acidity, we’re talking about excess hydrogen ions (H+), but we’re just going to use the general term “acid.” Its a scary foreign phrase, but it just means “percentage of acids” Acid isn’t always a bad thing like in movies. The pH scale goes from 0-14, so neutral is 7 (water is neutral.)  The body needs a pH of 7.35-7.45 to maintain homeostasis. 0.5 in either direction away is not conducive to life. So, when we find someone whose acid levels are not conducive with life, we counteract the problem and restore homeostasis. You want to keep the body neither too acidic or too alkaline, you want to balance it. This is all Acid-Base balance means.

ACIDIC – TOO MUCH ACID – Lower than 7.35 means that there is too much acid in your system.
NORMAL – Just right! pH between 7.35 and 7.45 is perfect for homeostasis.
ALKALINE – NOT ENOUGH ACID - It just means NOT acidic enough. pH higher than 7.45 is considered Alkaline.

Test yourself
Your patient has a ph of 6.9    Is he acidic or alkalotic?
Your patient has a ph of 7.4    Is he acidic or alkalotic?
Your patient has a ph of 7.7   Is he acidic or alkalotic?
Your patient has a ph of 7.25  Is he acidic or alkalotic?
Your patient has a ph of 7.43  Is he acidic or alkalotic?
Your patient has a ph of 8.0    Is he acidic or alkalotic?

REALLY IMPORTANT 
You take in oxygen by inhaling, your body turns oxygen into carbon dioxide, you exhale and remove the carbon dioxide from your body.
Carbon dioxide is “respiratory acid.” When you’re not breathing adequately, you are not getting rid of this “respiratory acid” and it builds up in the tissues. The extra CO2 molecules combine with water in your body to form carbonic acid and makes your pH go up. This is bad.

How do we measure it?
We can measure the amount of respiratory acid in the arterial blood using blood gases. They measure the amount of each gas in your blood. We measure the pH, the amount of carbon dioxide (PaCO2) and the amount of oxygen in the blood (PaO2).

PaCO2 is the partial pressure of carbon dioxide. We can measure it to see how much respiratory acid (CO2) there is in the blood. We use arterial blood gas tests to check it. How much respiratory acid (CO2) should there be? The normal value is 35-45 mmHg (mmHg just means millimeters of mercury, its a measurement of pressure.)  The (a) in PaCO2 just stands for arterial. If you measured venous blood gasses, the levels are different and PvCO2 is used. If CO2 is HIGH, it means there is a buildup of respiratory acids because he’s not breathing enough CO2 away. If your pH is acidic, and your CO2 is HIGH, its considered respiratory acidosis. If CO2 is LOW, it means there are not enough respiratory acids because he’s probably hyperventilating too much CO2 away. When pH is high, and CO2 is high, this is called Respiratory Alkalosis.

Field Note:
On the trucks,  pETCO2 (End Tidal Carbon Dioxide) is sometimes used and is expressed as a percentage. instead of measuring the pressure in mmHg to measure the effectiveness of ventilations and circulation. A pETCO2 of 5-6% roughly equates to a PaCO2 of 35-45mmHg, so titrate your ventilations to achieve 5-6% pETCo2.

EMT Quick Rule for testing
Inadequate breathing  - Respiratory Acidosis – PH will be low, CO2 level will be high, because he’s not breathing it off.
Hyperventilating patients – Respiratory Alkalosis – PH will be high, CO2 levels will be low, because they’re breathing off too much CO2.

Making it simple:
If your CO2 is LOW, then DECREASE rate and depth of ventilations.
If your CO2 is HIGH, then INCREASE rate and depth of ventilations.

Review

Respiratory Acidosis
NOT Breathing adequately – NOT exhaling enough means you aren’t getting rid of CO2 therefore pCO2 (percent of Co2 is HIGH!)
Clinical Presentation: Altered LOC, Tachycardic, Diaphoresis, headache
Cause: Crappy or no respirations (COPD, Overdose, Pneumonia, Smoke inhalation, Pneumothorax, airway obstruction)
Treatment - Increase rate and depth of ventilations – Bag them, so you get rid of some CO2 for them.

Respiratory Alkalosis 
Blowing off too much CO2, as in hyperventilation. When there is not enough CO2 in the blood, the body uses bicarb to compensate for the lack of respiratory acid. (Metabolic compensation)
Clinical Presentation: Numbness or muscle twitch in fingers, toes, seizures
Cause: Shock, DKA Kussmaul Respirations – Deep and FAST breathing! (The body is trying to compensate for its metabolic acidosis by producing a respiratory alkalosis on purpose.) Caused by (anxiety, pain, fever, hypotension, hypoxia, CHF, PE, Sepsis)
Treatment: decrease rate and depth of ventilations. (Calm them down or stop bagging so fast.)

Test Yourself
Your patient’s PH is 7.25, and his PaCO2 is 20mmHg.   Respiratory Acidosis, Respiratory Alkalosis, or Normal?
Your patient’s PH is 7.75, and his PaCO2 is 20mmHg.   Respiratory Acidosis, Respiratory Alkalosis, or Normal?
Your patient’s PH is 6.25, and his PaCO2 is 45mmHg.   Respiratory Acidosis, Respiratory Alkalosis, or Normal?
Your patient’s PH is 7.55, and his PaCO2 is 69mmHg.   Respiratory Acidosis, Respiratory Alkalosis, or Normal?

Metabolic
Metabolic just means it has to do with metabolism. Metabolism just means the chemical changes that sustain life. Oxygen combines with glucose to create energy. Carbon dioxide is a waste product of this process. CO2 is then carried from the blood to the alveoli to the lungs for expiration. We blow off this respiratory acid when ventilations are sufficient. Your body produces a buffer known as bicarbonate that is alkaline and it binds up with excess acids and turns it neutral. Bicarbonate is like Tums for your bloodstream.

HCO3 is the amount of bicarbonate in the bloodstream. HCO3 is just the chemical name for bicarbonate. Normal is 22-26/mEq/l (milliequivalents per liter) This measures how much Tums are in your blood binding up the excess acid. If your HCO3 (Tums) level is 10, it means that there is not enough of it, and so the acid in your blood just builds up and the overall pH of your body goes DOWN! This is called Metabolic Acidosis. To fix it, we bring bicarbonate levels up by administering Bicarb via IV! If there’s too much, it binds up too much acid and there isn’t enough, so now your pH goes alkaline! This is called Metabolic Alkalosis. Fix it by keeping your patient stable long enough for the bicarb to work itself out.

Review

Metabolic Acidosis 
Acid in the blood is used to combine with oxygen and metabolize it. If you do not have enough oxygen rich blood circulating, the acid is not used and builds up.
Clinical Presentation: Tachycardia, Pulmonary edema, Tachypnea, confusion or coma
Cause: Cardiac arrest, renal failure, DKA, diarrhea for a long time, ASA or antifreeze Overdose
Treatment – Increase rate and depth of Ventilations. Consider Bicarbonate – Its like Tums for your blood. It binds up the acid in your body and turns it neutral.

Metabolic Alkalosis
Too much bicarbonate, not enough acid
Clinical Presentation: Seizures, Headache, Dysrhythmias
Cause: Diuretics, cystic fibrosis, chewing tobacco, penicillin, overzealous bicarb administration
Treatment: Keep them alive long enough for their body to use up the excess bicarb.

Handy Dandy Quick Reference Chart

Test Yourself 
If you have blood gases, first consider whether your patient is acidotic or alkalotic by evaluating the pH. Then, determine whether the cause is respiratory or metabolic.

Your patient has a PH of 7.25, a CO2 of 60mmHg and HCO3 22
Your patient has a PH of 7.25, a CO2 of 45mmHg and HCO3 40
Your patient has a PH of 7.4, a CO2 of 40mmHg and HCO3 25
Your patient has a PH of 7.25, a CO2 of 50mmHg and HCO3 21
Your patient has a PH of 7.45, a CO2 of 24mmHg and HCO3 22

Kidneys
The kidneys also have a fail safe switch on them. If your pH is too high when it hits the kidney filter, your kidney senses it and flushes MORE acid out with your urine. Similarly, if your kidneys sense that you don’t have enough acid, they kick out less acid into your urine. Unfortunately, the kidneys take awhile to process it, so it takes hours or days for it to compensate.

Field Note:
Your dialysis patients are chronically acidotic because their kidneys are not participating in the compensation system. So, if your dialysis patient crashes, assuring adequate ventilations and bicarb administration is even more vital.

 Advanced Learning Links
http://enw.org/ETCO2inCPR.htm

http://www.paramedicine.com/pmc/End_Tidal_CO2.html

http://www.the-abg-site.com/about.htm

What are they, Where are they, and What are they for?

Where to Listen

The location for auscultation of each heart sound is in the diagram above.
(M) Mitral (T) Tricuspid (A) Aortic (P) Pulmonic. The blue area is the pleura, pink is lung, red outline is heart.

Why should I care about heart sounds?

You can use heart tones in combination with other clinical findings to create a differential diagnosis and begin to treat heart failure and other cardiac pathologies en route. You can also provide a better picture to the ED, so they can treat your patient faster and more accurately. Paramedics and EMTs who know and listen to heart tones are the CSI team of cardiac EMS! By knowing what’s going on (or not going on) when you hear these sounds, it will make you a better medic. Its not hard, and you want to be a rock star, so learn them and practice them all the time. You’re not going to be able to pick out bad heart tones until you’ve listened to normal heart tones hundreds of times. As with everything clinical, practice practice, practice!

The two beats you should hear on a “normal” patient are called “Sound 1″ and “Sound 2.” We shorten this to S1 and S2. They are the two “Lub dub” beats you hear in a normal heartbeat.

The First Heart sound  (S1) “Lub”  is caused by the closing of the Mitral (Bicuspid) and Tricuspid atrioventricular valves.  If you want to review, we talked more about valves in our Quick and Dirty Guide to Cardiology I.  The first sound (S1, Lub) is caused by blood slamming shut these valves. They generally shut at the same time in healthy patients so you only hear one nice distinct “Lub” The mitral side is operating at a much higher pressure, so the sound will mostly be coming from it. Sometimes, when the two atrioventricular valves aren’t shutting at the same time, you can hear them both, with the tricuspid sound much quieter. When this happens, its called a Split S1, and it is normal for about 40% of patients. Split S1 is also common in RBBB because of conduction delays. The time that you hear the S1 represents the beginning of systole (when the heart flexes ventricular muscle and SQUEEZES the blood out of it. [Systole = Squeeze].

The Second Heart sound (S2) “Dub” is caused by blood slamming shut of the semilunar valves (Aortic and Pulmonic). They generally shut at the same time in healthy patients so you only hear one nice distinct “Dub.”  The left side (Aortic valve) is the loud one here because the left side of the heart is the high pressure side. Just like S1, these sounds can be split. The S2 sound means blood has left the ventricle and is no longer being allowed back in, so it represents the end of ventricular systole [systole =squeeze.]

Pro Tip: In Tachycardic (fast heart rate) patients, the two sounds “LUB DUB” sound the same sometimes and its hard to distinguish them. When you can’t tell which is which, feel a pulse while you’re listening. The Pulse is felt on every S1.

1.5 minute short video summarizing 1-2 again, so you can hear it and see it.

The Third Heart Sound (S3) “Ta”  is short and called “ta.” Its known as a ventricular gallop because it makes the heart tones sound like a horse galloping.  S3 is the sound of blood sloshing around in a compliant left ventricle. It occurs directly after “Dub” and is a lower pitch than “Dub.” It can be an important sign of heart failure. The best place to listen for an S3 is at the cardiac apex. (M in diagram)

Take 55 seconds and listen/watch S3 in action

The Fourth Heart Sound (S4) is rare. The best way to remember it is that it sounds like a gallop where the loudest sound (s1) comes in the middle. So, it sounds like Ta-LUB-dub, ta-LUB-dub. The S4 sound is usually caused by a failing left ventricle and is best heard at the cardiac apex.

Take 55 seconds and listen/watch S4 in action

Murmurs and Rubs

Murmers

A murmur is simply the sound of turbulent blood flowing through an incompetent valve. Sometimes hardening of the valve (stenosis) causes it to be unable to fully open or close, so blood is able to backflow against it. This is called regurgitation. It sounds like a miniature version of putting your thumb over the water hose.  Here is a chart to where and when you will hear the murmur and to the condition with which it is associated. For the most part, just remember that a murmur is turbulent blood flow through a failing valve. Depending on where its heard and at what stage of lub-dub, you can predict which valve it is!

Quick Reference

As an example, here is the sound of a mitral valve regurge with a picture so you can see and hear that the blood is leaking back into the left atrium!

Pericardial Friction Rub

Pericardial friction rubs are the sounds of two layers of the pericardium rubbing together. It sounds awful and is loudest during systole (between the lub and dub) It is indicative of pericarditis (inflammation of the pericardium) and your patient is usually a chest pain CC. You can also see signs of pericarditis on a 12 lead (more about that in ECG lessons.) Pericarditis is also a significant STEMI imposter, so listening for a friction rub can be an important part of your differential diagnosis!

Take 55 Seconds and listen to a Pericardial Friction Rub

Test Yourself 

Practice checking for s1, s2, splits, extra sounds and murmurs with this interactive online game. Very Helpful! 

More Knowledge

Blaufuss.org Heart Tones tutorial (Amazing!) 

Wikipedia Page on Heart Sounds

Advanced – Heart Tones PDF with a treasure of clinical criteria to be mined

Advanced Murmur Videos explaining a TON of information about murmurs and their diagnostic capability
Part 2: Murmur Pitch
Part 3: Putting it all together

MedicTests.com’s Quick and Dirty Guide to Heart Failure

As usual, I want you to break it down into parts that are easy to remember, and then practice them in order until they are second nature.

Assessment mnemonics – For this lesson, we’re not focusing on HOW to do an assessment as much as how to REMEMBER the steps!

Your ENTIRE medical assessment for the registry can be broken down into mnemonics – (BSMAC-GACCAT-OPQRST-SAMPLE-FVIT)

We’re going to go into each category and explain, but instead of trying to remember every single line of the assessment in order, this is a way to remember the whole list simply. All critical failure criteria is in red.

1. B-SMAC is the first section of the assessment, they are the first thing you do on a scene.

BSI
Scene Safe?
Mechanism?
Additional Units?
C-spine?

2. GACCAT – is your initial assessment. It stands for:

General Impression?
AVPU?
CC/Life Threats?
ABC’s (good Airway?, O2 and Breath sounds? Skin color, temp, condition?)
Transport Decision – Load and Go now (There are no stay and play scenarios in the registry practical!)

3.  OPQRST-I : These are slightly different based upon the type of medical call. We will use Chest pain as an example.

Onset- when did this start?
Provocation – what started it?
Quality – how would you describe it?
Radiation – Does the pain travel anywhere?
Severity – Scale of 1-10, how severe?
Time – How long has this been going on?
Interventions What have you done about it?

4. SAMPLE :  This should be familiar!

Signs and Symptoms – chief complaint and pertinent findings
Allergies – Are you allergic to anything?
Medications – What prescription medications do you take on a regular basis?
Past Med Hx – History of present illness (Has anything like this happened before?)
Last Oral Intake – When was the last time you had anything to eat or drink?
Events – What was going on just prior or leading up to the problem today?

5. FVIT – Once again, we’ll use EMT chest pain protocol as an example.

Focused History (Verbalized)
Vitals
Interventions – Nitro Example, but similar for all meds
1  Get orders for nitro (0.4mg sublingually) or state that you have a standing order
2  Check expiration date, right patient right dosage, right drug, make sure fluid is right consistency and color (not precipitated) , check for contraindications
3  Explain to patient effects of Nitro and reason for administration; doublecheck systolic over 100 and no ED meds or hx of sensitivity
4  Administer 1 spray or tablet of 0.4mg nitro under the tongue
5  Monitor for changes every 5 minutes (if poor, repeat 1-5 to a max of 3 doses.)
Transport (Reevaluate transport decision)

GACCAT again
Vitals again
Focused again

 BSMAC-GACCAT-OPQRST-SAMPLE-FVIT

Now look at the national registry skillsheet for EMT Medical or Paramedic Medical

Try to break it down in your mind so you can see the mnemonic

B-smac – Bsi, Scene safe, Mechanism, additional units, C-spine
Gaccat – General imperssion, Avpu, Chief complaint, ABCs, Transport
OPQRST - SAMPLE ( you know these!)
F-VIT – Focused, Vitals, interventions transport

Here’s a great video to go over and reinforce what you need to do for the National Registry Medical Assessment!

]]> http://medictests.com/how-to-memorize-the-national-registry-medical-assessment/feed/ 0 http://medictests.com/cardiology-ii/ http://medictests.com/cardiology-ii/#comments Wed, 23 Nov 2011 17:09:20 +0000 admin http://medictests.com/?p=1840 MedicTests.com’s Quick and Dirty Guide to Cardiology II: Coronary Circulation and Heart Attacks

The heart is an organ whose muscles require oyxgenated blood too!
Where does the heart muscle get its blood from? Where does it go? What happens when its blocked?

Answer: 1) The heart gets its blood from arteries that branch off of the aorta called Coronary arteries.

Answer 2) Blood goes through the two main coronary arteries into the walls of the heart muscle.

Answer 3.) When there is a block in the coronary arteries and blood cannot pass through to the walls of heart muscle, the muscle tissue dies. Then it is no longer able to “squeeze” and cannot help pump blood through your body. And then you die. This is how a heart attack happens!

Remember how blood leaves the left ventricle and shoots blood up over the aorta and to the rest of your body? Well, there are two branches off the aorta that go directly back to the heart. They are the left and right Main Coronary Arteries and they carry blood directly back to feed the heart oxygenated blood.

The Right main Coronary Artery feeds the right atrium, right ventricle, inferior (lowest) muscle wall of the left ventricle and most of the posterior (rear surface) of the left ventricle. We’re not up to electrophysiology yet, but to peek over the wall, the RMCA also supplies food to the SA, AV nodes and the near portion of the bundle of His. If there is ischemia(insufficient oxygenated blood flow) in the RCA, the AV node (atrioventricular) and SA node (sinoatrial) *sets the pace of the heart contractions,* is also affected. This is why your inferior MIs (dying heart tissue in lower heart wall) almost always come with bradycardia (heart rate <60). Look at the picture above and see how the blood flowing from the right coronary artery supplies blood to the heart. When there is a blockage of blood flow in the RMCA, the muscle tissue of the heart that rely on its blood does not receive its oxygenated blood and starts to die without it. This is called a myocardial infarction, or heart attack.

Left Main Coronary Artery branches into Left Anterior Descending and the left circumflex. The Left Anterior Descending (LAD) feeds the anterior and lateral surfaces of the left ventricle and the intraventricular septum. The left circumflex supplies blood to the left atrium, lateral wall of left ventricle (with LAD) and in 15% of the people, also the inferior and posterior walls of the left ventricle. If there is a blockage in the left circumflex, the left atrium and part of the left ventricle will not get enough oxygenated blood and the muscle tissue there starts to die. The LAD is responsible for the most blood flow to the left ventricle, which is the main pump, so if there is a blockage in the LAD that reduces distal blood flow, there is a much increased chance of death. That’s why LAD blockages are known as “widowmakers.”

Watch this excellent 2 minute video with a 3D simulation showing myocardial blood flow.

Video showing “hand mnemonic” for remembering which main coronary arteries do what…

So, a heart attack occurs when there is a blockage in the coronary circulation resulting in muscle tissue ischemia and muscle cell death! When you have inadequate blood flow and oxygen to your heart, it causes pain called Angina Pectoris, or “chest pain.”

So, how do we know when this is going on and what do we do about it? 

Stay tuned for part 3 of MedicTests.com’s Quick and Dirty Guide to Cardiology where we discuss Chest pain assessment tools, how to get a good history, cardiac diagnostic techniques and treatments that maximize survivability!

Anatomy of the Heart

Cardiology is the study of the heart. You want to be great at this, so I want you to study this a little at a time, and do not move on to the next part until you have an excellent grasp of this one. The way these guides will work, is that we will stack upon information learned in the last section. So, we will go from very general, to very specific, then back to general again as a way to help assimilate the information. There will be tests, videos and more to make sure you have the correct information. This isn’t a guide you want to “finish.” Its one you want to understand.

All of the parts of your body need oxygenated blood to survive. The two primary systems are the circulatory system and the respiratory system. The respiratory system is responsible for getting oxygen onto the blood. The circulatory system is responsible for getting oyxgenated blood to all the parts of your body and bringing the deoxygenated blood back to the lungs to get more oxygen.

Getting oxygenated blood to parts of your body is called perfusion. When you have enough oxygenated blood getting to the body part to make it function correctly, you have good perfusion. If you have inadequate oxygenation to the tissues of the body, you have poor perfusion. Inadequate tissue perfusion is hypoperfusion, also known as shock. Example: “Hypovolemic shock” is inadequate tissue perfusion secondary to a lack of blood volume. Cardiogenic shock is inadequate tissue perfusion caused by a pathology in the heart.

The circulatory system is composed of vessels and a pump. The pump is the heart. Its a pouch of muscle that squeezes. Blood goes into the heart, and an electrical signal makes the heart contract, forcing the blood out of it and into your body. The heart is about the size of a fist and sits directly in the center of your chest, between your sternum and spine.

Basic CardioAnatomy

Right Right Lungs, Left Left Tissue

The heart is an organ with 4 pockets in it called chambers. Each chamber has a  particular function. The RIGHT side of your heart’s job is to pump blood to the pulmonary circulation for oxygen onloading. The LEFT side of your heart’s job is to pump oxygenated blood to your tissue. Your body uses the oxygen in your blood for energy. After your body uses the oxygen in it, the “used” blood feeds into the right atrium. It flows from the right atrium through the tricuspid valve into the right ventricle. The right ventricle squeezes, and shoots that blood through the pulmonic value into the pulmonary artery and to the lungs. There, the blood is reoxygenated. The oxygenated blood, then travels through te  pulmonary veins into the left atrium.  The blood goes through the “bicuspid” or “mitral” valve to the left ventricle.  The left ventricle contracts and shoots that oxygenated blood over the aorta and to the body to provide oxygen to tissues and organs!

The order that blood flows through the chambers is Right Atrium, Right Ventricle, Lungs, Left Atrium, Left Ventricle, Tissue.  Right, right, lungs! Left, left, tissue! Right, right, lungs! Left, left, tissue!  Train your brain!

Follow a drop of blood around the heart to the beat!

Valves – The Pigs Big Ass

The valves prevent blood from backing up and keep it all flowing in the right direction. That’s the only purpose of valves. They work like the 1 way valves on a BVM. Take a look at it next time you have a BVM near you. If there is a problem with the valve, that means blood is able to flow the wrong direction. The valves are just named by their shape. The pulmonic semilunar valve is just called that because it is a halfmoon in shape and it goes to the pulmonary system. The easy way to remember the bicuspid/tricuspid order is to remeber that you ride a tricycle before you ride a bicycle. The tricuspid always comes first. Its on the right side and separates the right atrium from the right ventricle. The bicuspid separates the left atrium from the left ventricle. So, the order of the valves… Tricuspid Valve, Pulmonic valve, Bicuspid Valve, Aortic valve. A way to remember the order of the valves = The Pigs Big Ass. TPBA = Tricuspid, Pulmonic, Bicuspid, Aortic.

Major Vessels

Vessels moving blood toward the heart are called Veins. Vessels moving blood away from the heart are called arteries. The big vessel that feeds “used” blood into your right atrium is called the vena cava. Its divided into 2 parts. The superior vena cava brings blood from your head and arms. The inferior vena cava brings blood back to the heart from your lower body.  After that blood goes through the tricuspid valve and into the right ventricle, the right ventricle SQUEEZES and shoots the blood into the pulmonary artery which goes to the pulmonary circulation. It is there that oxygen is put back into the blood. After moving through the pulmonary circulation, the blood then goes through the pulmonary veins into the left atrium. The left atrium dumps the blood through the bicuspid valve into the left ventricle. The left ventricle SQUEEZES, and shoots the blood up over the Aorta, which is the giant artery that feeds blood to the rest of the body.

So… lets review already… a drop of blood travels…  chambers are in blue, major vessels in red, valves in green

Tissue – Vena Cava – Right Atrium – Tricuspid  Valve – Right Ventricle – Pulmonic valve –  Pulmonary Artery – Lungs -

Pulmonary Veins – Left Atrium - Bicuspid Valve – Left Ventricle – Aortic Valve – Aorta -Tissue

Here is a picture with all of these structures shown in approximate locations.

Label the Heart – Game

With your mind… imagine 1 drop of blood flowing and follow it mentally through each section of the heart

Anatomy of the Heart

Video to help assimilate this knowledge and a headstart for advanced cardioanatomy!

Practice and test your knowledge.

Interior Heart Anatomy Learning Tutorial
Posterior Heart Anatomy Learning Tutorial

Simple Cardioanatomy Games

http://www.purposegames.com/game/heart-anatomy-quiz

Anatomy Bowl – CardioAnatomy - SUPER FUN! Compete online!

Look for our next section in MedicTests.com’s Quick and Dirty Guide to Cardiology
Coming soon at MedicTests.com!

Advice for New Paramedic Students

Congratulations to this year’s EMT and Paramedic students! Its going to be a fun year! Youre going to learn a lot and be completely overwhelmed at certain points. My instructor told me on our first night of paramedic school that he wanted me to go home and put my picture on the fridge. He explained that it was the only way my family would get to see me that year! Its true. This is going to take some time, but its worth it. At the end of this journey, you’re going to have something special. You’re going to have earned  a set of skills with which you can have an impact on the lives of your fellow man. Medic school is about shoving concepts into your head, fine tuning your understanding of the concepts, and then beating them into your brain over and over until they’re a part of you. By following these few simple tips, you will save yourselves TONS of hours, TONS of mental gymnastics,  and you’ll be a better medic. Throughout the year, MedicTests.com will be giving your more tips and tricks for surviving this year! Here are the first 3!

1. Preread. This is the biggest tip that distinguishes great medic students from those who just try to get by. If you’re going over a chapter in class tonight… just read the chapter before you go in. Highlight what you think are the important points. This way, when the instructor goes over it in class, it’s not the first time you have heard it, so it helps you understand the fine points better, helps you retain the entire subject better, and gives you the opportunity to clarify things that were foggy. The tendency in high school or other college classes is to get behind, then cram the bullet points right before the test. The problem is that this type of learning is that YOU DO NOT RETAIN IT! After the test is over, your brain will dump it. Then you have to learn it AGAIN for the next test and the final! You do not have all of these hours to spare. You can tell the people who do not preread the chapter, because they will be the ones with the confused face and saying “wait…what?” all night. Preread. Preread. Preread.

2. Do every skill as often as you can. Your EMT and Paramedic skills are lists! Just focus on a skill and do it over and over. Get comfortable with it. Whenever you hear the words “Who wants to go first?” ITS YOU! You want the first scary time, so you can really see where your at and how much work you need at the skill. Most people will want to “watch a few other people do it” first. This is NOT how real emergency medicine works. You need the practice and you need the pressure. You are going to make mistakes. You can make them in training, and risk being embarrassed in front of a group of students while youre in school… or you can make them in real life on real people. Beat it into your head. Go first. Then… when everyone is done, ask to do it one more time. When you have a break in class, do it again. You will find that the next time, you will be less nervous, and more in charge of the situation. Your magic words this year are “CAN I TRY THAT AGAIN?”

3. Ask early and often in clinicals. I have seen so many students come in and want to spend the day trying to be friends and acting like they are already good at everything. You might think they will be easier on you if you’re nice to them and like the same things. DONT DO THIS! If you’re checking off the truck first thing on your clinicals… make yourself ask a question. “Whats the difference in liter flow between a nebulizer and a nasal cannula?”  Ask to practice a skill. Ask to do a medical assessment. Always go into a clinical to practice your skills with real paramedics and EMTs. DO NOT wait for the calls to come out. If you get good calls or patients while on a clinical, its a bonus. After each call, ask why they did what they did… even if you think you already know. It gives you a chance to see what they’re thinking. Do not wait for the calls to practice your skills. Start in the morning. Ask what the hell perfusion really means. Ask them exactly how exactly Epinephrine works. Ask to practice doing a hypoglycemia call. Practice practice practice. When you do this, a magical thing happens:  when they realize you’re curious to learn, they explain MORE throughout the day on their own! Youre a student on a 12 hour mission to learn about medicine from medics. Hunting and computers are great, but on your first clinical with a crew, establish yourself as a someone who gives a damn about what they’re doing.

Every success is built on the ability to do better than good enough.  The stuff YOU are learning in class will make a difference in the lives of REAL people. You WILL change lives. Dedicate yourself completely to your craft. Pre-read your material, practice skills as often as you can and be aggressive.  MedicTests.com will be there with you all year to make sure that our students are the most prepared, most practiced, and most highly trained medics in the field.  There is no “good enough” in this job. You must become great. This is not a job for the timid. You are worthy of this challenge.

Nasal Cannula Approximations : Rule of thumb 4% FiO2 for each liter
1L : 24%
2L: 28%
3L: 32%
4L: 36%
5L: 40%
6L: 44%

Simple masks, Trach masks
deliver FiO2 of 40-50% with a minimum liter flow of 5-12 LPM. Do not use a simple mask with liter flow at lower than 5LPM because you need the pressure to be high enough to flush the CO2 out of the mask.

Nonrebreather masks
deliver FiO2 of 60-100% and you can titrate O2 to the patient’s inspiratory needs… ie. the bag should not deflate completely on inspiration.

Tools, Videos and links!

This video is the best one I’ve found on the internet in explaining the different FiO2′s for infants, peds and adults in various circumstances!

Awesome Slideshow presentation with lots of great information on oxygen application systems

MedicTests.com Quick and Dirty Guide to CHF and Pulmonary Edema

HEART FAILURE means the heart is not pumping enough blood to keep the organs alive. Since its unable to pump the blood fast enough, the blood ON THE WAY TO THE HEART gets backed up in the veins. Reduced blood flow to the kidneys results in water retention. You end up with fluid in the lungs and edema on the body. This is a very serious condition. You need to handle both the “pump” problem and the fluid problem in a quick way. Look for signs of hypoventilation and be ready to BVM or intubate these patients immediately. Use CPAP to keep alveoli open and O2 going in. Reduce the workload on the heart by using drugs like Nitroclycerin, and getting the fluid off by using drugs like Furosemide (Lasix.)

Diagnosing CHF

When you’re called out for a CHF emergency, its mostly likely going to be toned out as a shortness of breath or respiratory distress. Go through your normal ABCs, look for signs of cardiogenic shock such as cyanosis, clammy, and  diaphoretic skin. CHF’ers will have coughing, labored breathing, and wheezing. Listen for rales in lower lung lobes, tachypnea and pitting edema in legs. Look at the neck tilted in a 45 degree angle and look for jugular veinous distention (JVD) that is common with CHF.  So, basically, even if your patient is in mild respiratory distress, this condition can build upon itself and become life threatening in a hurry. Be ready to intubate if the patient’s respiratory distress worsens.

Physical exam –

• Inspect face and neck:  for pursed lip breathing (an effort to pressurize the lungs) and accessory muscle use (muscles will exhaust soon.) Check jugular vein distention, it is a sign of right sided heart failure resulting from severe pulmonary congestion.
• Sputum production:
  • Thick, green, or brown sputum may indicate pneumonia
  • Yellow or pale gray sputum may be related to allergic or inflammatory causes
  • Pink, frothy sputum is associated with severe and late stages of pulmonary edema
• Chest Wall – inspect chest wall for signs of trauma, barrel chest from COPD or accessory muscle use. Listen for breath sounds. Equal? Adventitious?
• Extremities : Check for peripheral cyanosis – its caused when a lot of the hemoglobin in the blood isn’t carrying oxygen. Clubbing of the fingers is caused by chronic hypoxemia. Carpopedal spasms are spasms of the hands, thumbs, feet or toes, and are associated with hypocapnia. They come from long periods of rapid, deep respiration.

Cardiac monitor and 12 Lead – You will typically see signs of Left Ventricular Hypertrophy on a 12 lead, but CHF can result in a myriad of dysrhythmias you may need to manage as well.

Auscultate heart tones - Normal heart beats consists of 2 sounds: (s1 and s2) Lub, dub… lub, dub…. lub, dub: If you hear extra heart tones, we use the sound “ta” or (S3)

The “Lub” sound (S1) is created by the closing of the bicuspid and tricuspid valves at the beginning of ventricular systole.
The “Dub” sound (S2) is creatd by the closing of the aortic and pulmonic semilunar valves at the end of ventricular systole.

If you hear an extra sound, it means the bicuspid and tricuspid valves are closing at different times, making 2 noises…
SO : S1-S2-S3 (Lub-dub-ta) = CHF

(S4-S1-S2-S3) (Ta-lub-dub-ta) indicates core pulmonare (right heart failure secondary to chf)

Sample CHF Protocol:

Place pt in position of comfort (Generally, CHF pts will not be able to lie flat.)
Apply O2, Establish IV , get CPAP ready and keep intubation kit close
Make sure its CHF – Look for signs of poor perfusion, edema, rales in lower lung lobes, tachypnea, JVD and difficulty speaking. Pneumonia can look like CHF, and pneumonia pts are frequently dehydrated. Giving diuretics to a dehydrated pneumonia patient with congestion will result in very bad things.

Administer Nitroglycerin 0.4mg SL up to 3 times, of course making sure that you have an IV, Pt BP >100, and pt is not on enhancement drugs.
Initiate CPAP or assist ventilations with PEEP valve
Administer LASIX 40mg IVP SLOWLY over 2 minutes. If your pt takes Lasix regularly, use 80mg instead. Maintain BP>100.
CONSIDER Morphine 4mg IVP SLOWLY over 2 minutes.

Nuts and bolts

Left Ventricular Failure (LVF) and Pulmonary Edema - possibly due to chronic hypertension, electrolyte imbalance: results in reduced ejection fraction (percentage in decimal of the amount of blood that left ventricle puts out with each contraction.) 85 to 90% is normal ejection fraction expressed as .85 to .90. As ventricle fails, contraction is not as strong, it wont squeeze with same amount of intensity, so ejection fraction falls. If EF falls below .6 then you need to figure out whats wrong. When you get down to .45, its called CHF.
- Left ventricle fails to function as an effective forward pump
- Causes back-pressure of blood into pulmonary circulation - causes pulmonary vascular distention. Pulmonary capillaries – as they distend, the area inside the capillary distends and the internal pressure increases, and it pushes serum and fluid out. Blood cells stay inside capillaries, but fluid goes out because the walls are only 1 cell wall thick. You end up with fluid buildup between the capillary walls and the alveolus by almost 10 times. Its normally 1 micron distance in order to pass oxygen. If the space is increased 10x, oxygen can no longer pass freely in the built up interstitial fluid. Crackels (rales) is the sound you hear when air is “bubbling” through the fluid at the alveolar level.

Links and Tools

Cardiogenic Shock/ CHF Flash Cards

Wikipedia Entry for CHF

Each GROUP of muscles, nerves and vessels are kept separated from each other into little compartments by a fibrous mesh. (Example: Compartments in the leg) This mesh is called fascia. When the muscles inside the fascia are damaged, they swell. Fascia (the netting that holds the group together) does NOT expand to permit the swelling. So, what happens is that the swelling increased the pressure within the “compartment” to the point where it doesn’t allow blood flow or transmission of sensory impulses. If it isn’t handled quickly, the muscle tissue goes too long without oxygen, it dies and the extremity must be amputated.

The most common situations where you will find compartment syndrome is in the calf or forearm after a car accident or other traumatic blunt force injury.  Look specifically for decreased sensation, severe pain that doesn’t respond to painkillers and gets worse over time as pressure increases and gradual weakness or loss of sensation distal to injury site. The skin over the area may be swollen and waxy looking. Squeezing the compartment or moving the affected part will evoke extreme pain.

When you get to the ER, they will confirm the diagnosis by attaching a pressure gauge on the end of a needle and jamming it into the muscle to measure pressure within the compartment. If confirmed, the patient will need surgery where they will cut the fascia to relieve the pressure, similar to the reasoning behind an escharotomy in severe burn patients. All of that pressure has to be released. A follow up surgery is required to close the fascia again in a few days. As long as the compartment syndrome has been addressed before muscle and nerves begin to die, the prognosis is great!

One of the most common questions missed in the EMT and Paramedic OBGYN test involve the terms Gravida and Para.

No one wants to hear the paramedic yell over the radio and then to the ER staff that “this chick has been pregant 5 times; she had two kids, two miscarriages and an abortion.” So, since these are pertinent factors that need to be communicated in some OB calls, we use G/P/A.

Quick version: Gravida means pregnancies and Para means live births. If your patient has had a miscarriage and two live births, you could say she was Gravida 3, Para 2 or simply G3 P2. If the patient has had an abortion, a third notation (A) for Abortus can be used.

A more detailed explanation of the rules and finer points courtesy of Wikipedia:

• Gravida indicates the number of times the mother has been pregnant, regardless of whether these pregnancies were carried to term. A current pregnancy, if any, is included in this count.
• Para indicates the number of viable (>20 wks) births. Pregnancies consisting of multiples, such as twins or triplets, count as ONE birth for the purpose of this notation.
• Abortus is the number of pregnancies that were lost for any reason, including induced abortions or miscarriages. The abortus term is sometimes dropped when no pregnancies have been lost.

Therefore, the history of a woman who has had two pregnancies (both of which resulted in live births) would be noted as G2P2. The obstetrical history of a woman who has had four pregnancies, one of which was miscarried, would be noted as G4P3A1. That of a woman who has had one pregnancy of twins with successful outcomes would be noted as G1P1