ICCM - Final Exam

what is the acid-base equilibrium equation?

CO2 + H2O ⇌ H2CO3 ⇌ HCO3− + H+

what is a complication of respiratory acidosis?

ventricular fibrillation -> death

what is the normal range for blood pH?

7.35 - 7.45

what is the normal range for CO2 on ABG?

35 - 45

what is the normal range for HCO3 on ABG?

22 - 26

what population is at risk for respiratory acidosis?

COPD patients

what are the causes of respiratory acidosis?

lung - COPD, asthma, pneumonia, CHF, hypoventilation

rib - flail chest

muscle - dystrophy

brain - myasthia gravis, botulism, ALS, polio, guillain barre, multiple sclerosis, tumor

acute vs chronic presentation for respiratory acidosis

acute - for every 10 mmHg above 40 for PCO2, the pH will go down 0.08

chronic - for every 10 mmHg above 40 for PCO2, the pH with go down 0.04

acute on chronic - somewhere in between these values

what does ROME stand for?

R - respiratory

O - opposite

M - metabolic

E - equal

partial vs complete compensation

partial - pH is still out of range

complete - pH is back to normal range, but borderline abnormal still

what are causes of respiratory alkalosis?

anxiety/nervousness, hyperventilation, fever, pain, ASA overdose

what are causes of metabolic acidosis due to too much H+?

lactic acid - sepsis, shock, hypoxia

citric acid - citrus fruit

keto acid - DKA, starvation, alcohol

exogenous source - aspirin, methanol, ethylene glycol

distal nephron - polycystic kidney disease

what are causes of metabolic acidosis due to not enough HCO3?

proximal nephron - lupus, sarcoidosis, rheumatoid arthritis

GI - diarrhea

what are causes of metabolic alkalosis due to not enough H+?

vomiting, loop diuretics, sustained hypokalemia

what are the causes of metabolic alkalosis due to too much HCO3?

exogenous - tums (calcium carbonate), baking soda

what percent of oxygen is normal air?

21%

what is the max for nasal cannula?

6 liters

what is the max for venti-mask?

up to 50% oxygen

what is the max for a non-rebreather?

15 liters

what are the options for supplemental oxygen and airway management?

1. nasal cannula

2. venti-mask

3. non-rebreather

4. CPAP

5. BiPAP

6. intubation

how much does 1 liter of oxygen increase the inspired oxygen concentration by?

1 L with raise it 3% (from 21% to 24%)

then every liter after that is 4% (ex. 2L - 28%, 3L - 32%, etc.)

how much pressure is needed to keep normal lung inflated?

5 - 6 liters of pressure

what is CPAP and what is a setting for a healthy person?

continuous positive airway pressure

6 cm H2O

what is CPAP commonly use for?

sleep apnea

what is BiPAP and what is a setting for a healthy person?

bilevel positive airway pressure

similar to CPAP but there are two levels of pressure given

8 / 4 cm H2O - top number is inhalation, bottom is exhalation

what are medications used for rapid sequence intubation (RSI)?

sedative - etomidate, ketamine, or propofol

paralytic - succinylcholine (fastest, but don't use with hyperkalemia), rocuronium, or vecuronium

what are the components to ventilation settings?

tidal volume - the amount of air that moves in and out of the lungs with each normal breath

respiratory rate

FIO2 - fraction of inspired oxygen

positive end-expiratory pressure (PEEP) - the pressure remaining in the lungs at the end of exhalation, above atmospheric pressure, used to keep alveoli from collapsing (normal 5)

what is the history of cephalosporins?

discovered starting in 1945 when Italian scientist Giuseppe Brotzu found a Cephalosporium acremonium fungus

what is the mechanism of action for cephalosporins?

inhibit bacterial cell wall synthesis

what are the side effects for cephalosporins?

local irritation with IV or IM, nausea and diarrhea with oral intake, renal toxicity (uncommon), and cross-reactivity

first generation cephalosporins

cephalexin (PO), cefazolin (IV)

gram + (staph and strep), some gram - coverage

second generation cephalosporins

cefuroxime (PO), cefoxitin (IV), cefotetan (IV or IM)

gram + (staph and strep), some gram - coverage

third generation cephalosporins

ceftriaxone (IV or IM), cefpodoxime (PO), ceftazidime (IV)

broad gram - (ceftazidime covers pseudomonas), some gram + coverage

fourth generation cephalosporins

cefepime (IV)

broad gram - (including pseudomonas), some gram + coverage

fifth generation cephalosporins

ceftaroline (IV)

broad gram -, some gram + coverage (including MRSA)

what is the history of macrolides?

isolated in 1950 from the bacterium Saccharopolyspora erythraea. it was first used clinically in 1952, often as a penicillin alternative for patients with allergies

what is the mechanism of action for macrolides?

bind reversibly to the 50S subunit of the bacterial ribosome inhibiting protein synthesis

what are the macrolide medication names?

erythromycin

azithromycin - shortest half-life

clarithromycin

what is the coverage for macrolides?

gram +, gram -, atypicals

what are the side effects of macrolides?

diarrhea

additionally - cardiac toxicity, ototoxicity and tinnitus

what are the four types of shock?

hypovolemic

cardiogenic

distributive

obstructive

what is shock?

body isn't getting enough blood flow and oxygen to its tissues and organs due to low blood pressure

what organs are impacted by shock?

kidneys (first)

lungs

heart

brain

liver (last)

what is the blood pressure equation?

blood pressure = cardiac output (CO) × systemic vascular resistance (SVR)

what is the equation for cardiac output?

cardiac output = stroke volume (SV) × heart rate (HR)

what is hypovolemic shock and how does the body respond?

what? - not enough blood to pump

equation - decreased stroke volume, increased heart rate, increased systemic vascular resistance

what can cause hypovolemic shock?

blood - trauma, GI (peptic ulcers, diverticula), postpartum bleeding (uterine atony)

non-blood - dehydration, polyuria, burns

what is cardiogenic shock and how does the body respond?

what? - heart is unable to pump enough blood to meet the body's needs

equation - decreased stroke volume, decreased heart rate, increased systemic vascular resistance

what can cause cardiogenic shock?

MI, CHF, arrhythmias, myocarditis, valve disease

what is distributive shock and how does the body respond?

what? - widespread decrease in blood vessel tone and blood flow, leading to inadequate tissue perfusion

equation:

septic and anaphylactic - increased stroke volume, increased heart rate, decreased systemic vascular resistance

neurogenic - decreased stroke volume, heart rate, and systemic vascular resistance

what can cause distributive shock?

sepsis

anaphylaxis

neurogenic

more on septic shock

due to gram - (release endotoxin) or gram + (release exotoxin)

these toxins damage the cells causing release of histamine, prostaglandin, and leukotrienes. they then lyse and cause leaky vessels

more on anaphylactic shock

pathway: peanut -> B cell releasing IgE -> mast cells releasing histamine, prostaglandin, and leukotrienes -> cells lyse and cause leaky vessels

more on neurogenic shock

due to a brain or spinal cord injury - the body is wanting to raise the blood pressure, but brain is unable send the signals

what is obstructive shock and how does the body respond?

what? - heart and vessels are fine, but obstruction is present

equation - decreased cardiac output, decreased heart rate, increased systemic vascular resistance

what are the causes of obstructive shock?

pleural effusion, tension pneumothorax, cardiac tamponade

dental infections

outpatient - augmentin or clindamycin

inpatient - vancomycin and zosyn

lung infections

outpatient pneumonia - levofloxacin, augmentin, azithromycin, or doxycycline

inpatient pneumonia - ceftriaxone and azithromycin or levofloxacin

derm infections

cat/dog bite - augmentin or clindamycin

simple cellulitis - cephalexin

large cellulitis (MRSA) - doxycycline, bactrim, or clindamycin

GI infections

diverticulitis (E.coli, bacteroides) - ciprofloxacin and metronidazole

outpatient colitis - ciprofloxacin and metronidazole

inpatient colitis - zosyn

GU infections

outpatient UTI - ciprofloxacin, bactrim, augmentin, cephalexin, levofloxacin, doxycycline, clindamycin, macrobid

inpatient UTI - ceftriaxone

ESBL UTI - carbapenem

what is the history of clindamycin?

first made in 1966 from lincomycin

what is the mechanism of action of clindamycin?

bind reversibly to the 50S subunit of the bacterial ribosome inhibiting protein synthesis

what is the coverage of clindamycin?

gram + (MRSA), gram -, anaerobes

what are the side effects of clindamycin?

diarrhea (risk of C. diff superinfection), skin rash

what is the history of bactrim?

discovered in 1968

combined two antibiotics, sulfamethoxazole and trimethoprim, to create a more potent drug

what is the mechanism of action of bactrim?

inhibit dihydropteroate synthase, blocking folate synthesis

what is the coverage of bactrim?

gram + (MRSA), gram -

what are the side effects of bactrim?

stevens-johnson syndrome, nausea, vomiting, diarrhea, crystalluria, dermatologic hypersensitivity (sulfa allergy)

what is the treatment for SJS

send patient to burn unit and IVIG

what is congestive heart failure?

a pump problem leading to fluid back-up in the legs and lungs

how do you classify heart failure?

left ventricular ejection fraction (LVEF) and symptoms

what are causes of heart failure?

chronic hypertension

diabetes

dyslipidemia

CAD

MI

valvular disease

drugs

what are the signs/symptoms of heart failure?

dyspnea, edema, weight gain, etc

what are the two types of heart failure?

reduced ejection fraction and preserved ejection fraction

what is the first medication that you need to give for a CHF exacerbation and why?

nitroglycerin

it is a vasodilator for the veins (SVC and IVC) which reduces the workload on the heart and alleviates symptoms like pulmonary edema

what is the other medication given for CHF exacerbation and why?

loop diuretic

relieves symptoms of fluid overload, such as shortness of breath and swelling, by forcing the kidneys to excrete excess salt and water

what are you going to see on physical exam for a patient with a CHF exacerbation?

signs of fluid overload

such as jugular venous distension, peripheral edema, and rales or crackles in the lungs

route and dosage options of nitroglycerin for CHF exacerbation

sublingual - 0.4 mg q 5 min as needed

IV - 5 mcg/hour

paste/lotion - 1/2 to 1 inch thick

what are side effects of nitroglycerin?

headaches, dizziness, low blood pressure, flushing

what is the mortality rate for a patient after being seen for a CHF exacerbation in the ED?

50% in 5 years

what is the mortality rate for a patient after being seen for flash pulmonary edema in the ED?

50% in 2 years

route and dosage of loop diuretics for CHF exacerbation

furosemide (Lasix) - 40 mg PO or 20 mg IV

torsemide (Demadex) - 20 mg PO or 10 mg IV

bumetanide (Bumex) - 1 mg PO or 0.5 mg IV

how would you compare the loop diuretics?

furosemide -> torsemide -> bumetanide

more potent, harder on the kidneys, and more expensive

if someone takes 80 mg PO of furosemide at home, how much torsemide IV would they need in the ED?

40 mg IV

what is the general rule for dosing loop diuretics in the ED for CHF exacerbations and why?

double the dose that they are on at home

want to give enough to alleviate the patient's symptoms, but not too much to cause dehydration

what labs and imaging should you order for a patient coming in with dyspnea?

labs - CMP, CBC, troponin, Mag, BNP

imaging - EKG and chest x-ray

what is your differential diagnosis for bilateral, symmetric leg edema?

CHF exacerbation

end-stage kidney failure

liver failure

hypothyroidism

lymphedema

what is severe hypothyroidism called and what sign is present?

myxedema coma - pretibial edema

what is cardiac tamponade?

fluid in the pericardial space

what are signs/symptoms of cardiac tamponade?

dyspnea, jugular vein distention, muffled heart sounds, hypotension

what is Beck's Triad?

jugular vein distention

muffled heart sounds

hypotension

what can cause cardiac tamponade?

acute onset - trauma, MI, aortic dissection, pericardial effusion

slow onset - autoimmune, malignancy, chronic inflammation, pericarditis, hypothyroidism, connective tissue disorders

what population do you see cardiac tamponade the most?

patients with autoimmune diseases

what do you see on EKG for cardiac tamponade?

electrical alternans - beat-to-beat alternation in the QRS

tachycardia

low QRS complex voltage

what do you see on echo for cardiac tamponade?

swinging heart in the pericardial sac

what do you see on x-ray for cardiac tamponade?

water bottle shaped heart

what do you see on ultrasound for cardiac tamponade?

pericardial Effusion

RA systolic collapse

RV diastolic collapse

plethoric IVC

what is the treatment for cardiac tamponade?

emergent pericardiocentesis

what trial supports lisinopril/lorsartan, amlodipine, and hydrochlothiazide as treatment options for hypertension?

Systolic Blood Pressure Intervention Trial (SPRINT)