Angela’s Critical Care

Question 1

What ratio of crystalloid replacement is needed to replace blood loss?

Answer 1

Notes say: 3 to 1

This seems old school and more commonly is about 1.5:

see UTD: maintain intraoperative normovolemia… replacement of sensible and insensible losses, fluid boluses (typically 250 mL) in volume responsive patients, and replacement of lost blood on a 1.5:1.0 volume basis until a transfusion threshold is met.

3:1 for severe stress response to surgery (per UTD) (AW)

Question 2

What two measurements help establish endpoints of resuscitation immediately postop?

Answer 2

Lactic acid and Base deficit

hemorrhagic shock resusc end pts-normalize lactate and base deficit (AW)

Question 3

Which ionotropes are preferred in cardiogenic shock?

Answer 3

Dopamine and dobutamine

Dobutamine is not a vasopressor but rather is an inotrope that causes vasodilation. most frequently used in severe, medically refractory heart failure and cardiogenic shock and should not be routinely used in sepsis because of the risk of hypotension. IT DROPS SVR.

Dopamine has dose-dependent effects - changing the dose of the drug is akin to switching vasopressors. When used for cardiac failure, dopamine should be started at 2 mcg/kg per minute and then titrated. CANNOT GIVE IF PULMONARY EDEMA, MAKES IT WORSE.

Question 4

Patient with a low systemic vascular resistance (300) and high cardiac output has what type of shock?

Answer 4

Septic

Low SVR, splanchnic vasoconstriction, increased cardiac output characterizes the hyperdynamic phase of septic shock

FYI: SVR is calculated as 80*(MAP-CVP)/CO, where MAP is mean arterial pressure and CVP is central venous pressure. The normal values of SVR range from 800 to 1200 dynes s/cm5

Question 5

Most important inflammatory mediators of SIRS are?

**TEST QUESTION **

Answer 5

TNF-a, IL-1, and IL-6

Question 6

Patient with sepsis has SVR 300-400, hypotensive, low/normal PCWP, low urine output. What is least useful drug?

A dobutamine
B dopamine
C levophed (norepinephrine)
D neosynephrine (phenylephrine)

Answer 6

dobutamine (drops SVR)

FYI: SVR is calculated as 80*(MAP-CVP)/CO, where MAP is mean arterial pressure and CVP is central venous pressure. The normal values of SVR range from 800 to 1200 dynes s/cm5

Dobutamine is not a vasopressor but rather is an inotrope that causes vasodilation. most frequently used in severe, medically refractory heart failure and cardiogenic shock and should not be routinely used in sepsis because of the risk of hypotension.

Question 7

Patient with h/o of CHF presents with low cardiac output, high SVR, pulmonary edema and increased PCWP (28). What drug is most useful?

Answer 7

dobutamine. This is the drug of choice for severe heart failure.

(do not give dopamine with pulmonary edema b/c it can cause pulmonary venoconstriction and worsen the problem)

FYI The normal pulmonary capillary wedge pressure is between 4 to 12 mmHg.

Question 8

Patient ventilated 100% FiO2 and high PEEP 14, tidal volume 500, mild A-a gradient, desaturating, and unstable. No mention of decreased breath sounds or tracheal deviation initial step in management?

A insert Chest tube without CXR
B start heparin
C VQ scan

Answer 8

start heparin. (basically barotrauma as red herring. work up PE, but treat first)

FYI: physiologic PEEP 4 mmHg. High PEEP —> barotrauma
Also oxygen concentration >60% considered to be potentially toxic and may result in pathologic changes similar to ARDS

High A-a gradients are associated with oxygen transfer / gas exchange problems. These are usually associated with alveolar membrane diseases, interstitial diseases or V/Q mismatch (PE)

Question 9

What is most sensitive value in preoperative pulmonary function tests in a known COPD patient?

Duplicate

Answer 9

NONE
Lit Review: preoperative spirometry was not predictive of complications following abdominal surgery. PFTs should not be performed routinely in patients undergoing nonresectional surgery. The degree of physiologic impairment (eg, FEV1 or FVC) does not correlate with the risk of postoperative pulmonary complications.

IF ANY, lower preoperative spirometry FVC, NOT FEV1 or FEV1/FVC, may predict PPCs in high-risk patients undergoing laparoscopic abdominal surgery

—
Notes say: (FEV1/FVC <70% would be a very poor perioperative indicator), but this is definition of COPD

Lit review: Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria Classification of severity of airflow limitation in COPD:
- a postbronchodilator FEV1/FVC ratio of <0.7 is considered diagnostic for COPD.
- GOLD system categorizes airflow limitation into stages. In patients with FEV1/FVC <0.7:

GOLD 1 - mild: FEV1 ≥80% predicted
GOLD 2 - moderate: 50% ≤ FEV1 <80% predicted
GOLD 3 - severe: 30% ≤ FEV1 <50% predicted
GOLD 4 - very severe: FEV1 <30% predicted.

I think question is more what is sensitive PFT test for COPD pt not what is required testing (AW)…

Question 10

What is the most common finding with ARDS?

Answer 10

hypoxemia refractory to o2 therapy was an answer

Defining criteria:
1. Acute onset after defined insult.
2. Bilateral diffuse infiltrates on CXR
3. No evidence of left atrial hypertension, CHF or Pulmonary Artery Wedge Pressure/Pulmonary Artery Occlusion Pressure <= 18 mmHg
4. Impaired oxygenation * most important criteria* PaO2/FiO2 </= 300mmHg

Question 11

Which of the following is least likely to affect an A-a gradient?
A ARDS
B pneumonia
C PE
D hypoventilation

Answer 11

hypoventilation

Question 12

What is the effect of high PEEP on central venous pressure?

Answer 12

Increased CVP and PCWP. Decreases venous return, stroke volume, cardiac output. Less increase in CVP when PEEP >10 (AW)

Given that PEEP increases right atrial pressure and, thus, CVP through the increase in intrathoracic pressure, it is generally believed that any increase in PEEP is expected to reduce blood flow by increasing the back pressure to venous return, resulting in a reduction in stroke volume index.

PEEP can decrease cardiac output through a decrease in cardiac preload and/or an increase in right ventricular afterload.

old answer/study guide:Decreases venous return, CVP, stroke volume, cardiac output and PCWP

Question 13

Which of the following is the most appropriate postoperative monitoring for an obese patient with sleep apnea?

A Telemetry
B CPAP
C ICU Admission
D PCWP monitoring
E Continuous pulse ox

Answer 13

Continuous pulse ox
CPAP (most appropriate treatment, but not really a monitor)

Question 14

What is a measurement that is an estimation of right atrial filling pressure?

Answer 14

CVP, Central venous pressure, which is a measure of pressure in the vena cava, can be used as an estimation of preload and right atrial pressure.

Question 15

What is a measurement that is an estimation of left atrial filling pressure?

Answer 15

Pulmonary capillary wedge pressure (PCWP) is frequently used to assess left ventricular filling, represent left atrial pressure, and assess mitral valve function.

normal PCWP is 8–12 mmHg

Question 16

Which measurement estimates preload?

Answer 16

CVP, Central venous pressure, which is a measure of pressure in the vena cava, can be used as an estimation of preload and right atrial pressure.

Notes said PCWP, which is incorrect

ETA: PCWP is the estimate of preload for the left ventricle. CVP is the measure of preload for the right ventricle. If the question doesn’t specifiy, then I would say they meant right. Can discuss further ***

Question 17

Which measurement would help distinguish cardiogenic and hypovolemic shock?

**TEST QUESTION **
(Duplicate)

Answer 17

Pulmonary capillary wedge pressure

(Aka pulmonary wedge pressure (PWP), pulmonary arterial wedge pressure (PAWP), pulmonary capillary wedge pressure (PCWP), pulmonary artery occlusion pressure (PAOP), or cross-sectional pressure)

Decreased in hypovolemic
Increased in cardiogenic

Question 18

What does Pulmonary capillary wedge pressure measure?

Answer 18

PCWP is frequently used to assess left ventricular filling, represent left atrial pressure, and assess mitral valve function.
It is measured by inserting a balloon-tipped, multi-lumen catheter (Swan-Ganz catheter) into a central vein and advancing the catheter into a branch of the pulmonary artery. The balloon is then inflated, which occludes the branch of the pulmonary artery and then provides a pressure reading that is equivalent to the pressure of the left atrium.

Question 19

Which of these is least acceptable in management of a fib?
A Beta blocker
B digoxin
C calcium channel blocker
D adenosine

Answer 19

adenosine (this drug is for SVT)

adenosine can cause afib in some pts

Question 20

What is initial pharmacologic treatment for atrial fibrillation?

Answer 20

Beta-blockers and calcium channel blockers are first-line agents for rate control in AF. These drugs can be administered either intravenously or orally. They are effective at rest and with exertion.

Intravenous diltiazem or metoprolol are commonly used for AF with a rapid ventricular response

Question 21

Which is least likely increase perioperative cardiovascular morbidity/mortality?

A critical aortic stenosis
B age > 70 years
C MI < 6 months
D moderate HTN
E unstable angina
F emergent operation

Answer 21

moderate HTN

Remainder are listed as risk factors within the multifactorial index of cardiac risk:

A critical aortic stenosis: 3 points
B age > 70 years: 5 points
C MI < 6 months: 10 points
E unstable angina: not listed in MICR but is a factor in RCRI
F emergent operation: 4 points

underestimates risk in vasc pts

Question 22

What are the Goldman Multifactorial Index of Cardiac Risk risk factors beginning with the riskiest? (9)

Answer 22

11pts. S3 heart sound or increased jugular venous pressure
10 pts. MI within 6 mos
7 pts. non-sinus rhythm other than PACs
7 pts. >5PVCs/min
5 pts. age >70 yo
4 pts. Emergency procedure
3 pts. Significant aortic stenosis
3 pts. Intra-abdominal procedure
3 pts. poor general health status

Question 23

What is the most sensitive test for MI?

Answer 23

troponin I

Question 24

What antibiotic do you use for SBE prophylaxis in PCN allergic patient?

Answer 24

PO: azithro or doxy (AW)
IV: cefazolin or CTX. last resort vanc (AW)

AHA/ACC 2007 Guidelines:
- Infective endocarditis prophylaxis for dental procedures is reasonable only for patients with underlying cardiac conditions associated with the highest risk of adverse outcome from infective endocarditis.
- Administration of antibiotics solely to prevent endocarditis is not recommended for patients who undergo a genitourinary or gastrointestinal tract procedure.

Abx used: amoxicillin or ampicillin —> keflex/Cefazolin or ceftriaxone if allergic; Azithromycin/clarithromycin or doxy as alternative

Notes say: Vancomycin if you do it at all but you very rarely should

Question 25

Which patients should undergo SBE propylaxis?

Answer 25

Pts w:
- Prosthetic cardiac valve or prosthetic material used for valve repair
- Previous Infective endocarditis
- Congenital heart disease (CHD) including unrepaired cyanotic CHD, palliative shunts and conduits
- Completely repaired congenital heart defect with prosthetic material or device during the first six months after the procedure
- Repaired CHD with residual defects at the site or adjacent to the site of a prosthetic patch or prosthetic device (which inhibit endothelialization)

For the following procedures:
- Dental procedures involve manipulating gingival tissue or perforating the oral mucosa.
- invasive respiratory tract procedures that involve incision or biopsy of the respiratory mucosa (e.g., tonsillectomy, adenoidectomy).
- Procedures of infected skin, skin structures, or musculoskeletal tissue

B&H:
Enterococci are part of the normal flora of the GI tract and are the primary bacteria from this area likely to cause IE. In patients with high-risk cardiac conditions (e.g., prosthetic heart valve, previous IE, or congenital heart disease) who receive antibiotics for wound prophylaxis, the inclusion of an antibiotic that is active against enterococci may be reasonable (e.g., penicillin, ampicillin, or vancomycin). However, no published studies demonstrate that such therapy will prevent enterococcal IE

Question 26

Which drug should be stopped prior to contrast administration?

Duplicate

Answer 26

Metformin

can cause life threatening lactic acidosis

Question 27

How do the FeNa, urine specific gravity, urine sodium, BUN:Cr, uCr:pCr, and Uosm differ in hypoperfusion and ATN?

**TEST QUESTION **

Duplicate

Answer 27

hypoperfusion / prerenal
FeNa <1%
SG > 1.025
Urine Na <20-30
BUN:Cr = elevated, >20:1 - increase in passive reabsorption of urea that follows enhanced proximal reabsorption of sodium and water
Urine Cr : plasma Cr: >20:1
Uosm HIGH = >500 mOsm/kg is highly suggestive of prerenal

ATN
FeNa >2-4%
SG 1.010; tubular damage loses renal concentrating ability
Urine Na >40-50 due to tubular damage
BUN:Cr = normal 10 to 15:1
Urine Cr : plasma Cr: <10:1
Uosm LOW = ~300 to 350 mOsm/kg (similar to the Posm). Uosm <500 mOsm/kg is not diagnostically useful

Question 28

Which of problems is least likely with blind loop syndrome?

A bacterial overgrowth
B B12 deficiency
C diarrhea
D fatty malabsorption
E iron malabsorption

Answer 28

iron absorption

bacterial overgrowth, diarrhea, fatty malabsorption, Deficiencies of fat soluble vitamins, and consumption of B12 occurs by anaerobic bacteria occur

Fe absorbed in duodenum (AW)

Question 29

Which drugs should you stop preop?

Answer 29

Oral hypoglycemics
Diuretics
Anticoagulants

Controversial
ACEI/ARBs

Depends
ASA/anti platelets

Question 30

Which drugs should you continue perioperatively?

Answer 30

Most, especially beta blocker, statins

Question 31

Which blood product to use to for low fibrinogen?

Answer 31

Cryo (Cryoprecipitate aka Cryoprecipitated antihemophilic factor (AHF)

rich in factor VIII (8), von Willebrand factor, and fibrinogen (and Factor XIII and fibronectin). contains at least 150 mg of fibrinogen per unit and 80 clotting units of factor VIII.
treat conditions characterized by acquired hypofibrinogenemia (e.g., disseminated intravascular coagulation [DIC]) and major bleeding requiring massive transfusion).
per UTD: no longer hemophilia or von Willebrand disease.

Cryoprecipitate is indicated in bleeding patients with fibrinogen concentrations less than 80-100 mg/dL. The usual dose is 5-10 units of pooled cryoprecipitate. Each unit will raise the fibrinogen level 7 to 10 mg/dL

Though FFP raises fibrinogen, there are only two indications for this product:
1) patients who require massive transfusion of PRBCs,
(2) patients on warfarin therapy who have an intracranial hemorrhage

AW: slightly updated with UTD numbers vs B&C

Question 32

When is it appropriate to use buffy-coat poor RBCS?

Answer 32

In patients with repeated febrile transfusion reaction from leukocyte antibodies

buffy coat is a layer of concentrated platelets and white blood cells (WBCs) that separates from red blood cells and platelet-poor plasma during blood preparation.

Question 33

What has the lowest risk of viral transmission?

A albumin
B PRBC
C platelets
D cryoprecipitate
E FFP

Answer 33

Albumin

• bacterial contamination is most common in platelets

Question 34

If a patient gets an air embolism from line placement, what should you try to do?

Answer 34

Left lateral recumb/trendelenburg, aspirate the air, supportive care

A patient with venous air embolization should be immediately placed into the left lateral decubitus position (Durant’s maneuver), Trendelenburg position, or left lateral decubitus head down position

Different than patient with arterial air embolism should be placed in the supine position

Question 35

What type of colon polyp is most likely to have associated cancer or a high risk of progression to cancer?

A Tubular adenoma
B hyperplastic
C tubulovillous adenoma

**TEST QUESTION **

Answer 35

villous adenoma or tubulovillous adenoma

Question 36

Know if the following antibiotics need dose reduction in renal insufficiency?
levaquin
flagyl
ceftriaxone
cefoparazone
vanc
zosyn

Duplicate

Answer 36

levaquin, vanc, zosyn need dose reduction

No dose reduction needed:
Flagyl, ceftriaxone, cefoparazone

Good resource: https://www.aafp.org/pubs/afp/issues/2007/0515/p1487.html

Most all antimicrobials need renal dosing except:
- Ketoconazole, micoconazole
- Cefoperazone, Ceftriaxone, Cefuroxime axetil
- Azithromycin, Dirithromycin, Erythromycin
- Dicloxacillin, Nafcillin, Penicillin VK
- Moxifloxacin, Trovafloxacin,
- Doxycycline
- Chloramphenicol, Clindamycin, Dalfopristin/quinupristin, Linezolid, Telithromycin
- metronidazole

Question 37

Side affects associated with lidocaine overdose?

Answer 37

agitation, dysphoria, confusion, ataxia, seizures, bradycardia from AV block, hypotension, N/V

tinnitus and blurred vision.
CNS depression, unconsciousness and coma.

Max dose (usually 4.5 mg/kg) - dont exceed 300mg
With vasoconstrictors such as epinephrine 1:200000 increases to 7 mg/kg (max dose 500mg)

Question 38

What shifts O2 dissociation curve to right?
What does shift to the right mean?

(Duplicate)

Answer 38

acidosis, CO2, hyperthermia

increase in the partial pressure of carbon dioxide (Pco2), a decrease in pH, or both, the last of which is known as the Bohr effect

rightward shift of the curve indicates that hemoglobin has a decreased affinity for oxygen, thus, oxygen actively unloads.

CADET - face RIGHT. Increased CO2, acidosis, elevated DPG, exercise, temp

left shift indicates increased hemoglobin affinity for oxygen and an increased reluctance to release oxygen

Question 39

What antibiotic has a high salt load?

Answer 39

ticarcillin disodium and clavulanate potassium
Timentin (be careful with CHF patients)

For the 3.1-gram dosage of TIMENTIN, the theoretical sodium content is 4.51 mEq (103.6 mg) per gram of TIMENTIN. Given q4h = >1200mg/day

Others of interest: ampicillin, unasyn, metronidazole, moxifloxacin, zosyn

TAZMNUM: kind of like Tasmanian
Tasmanian Devil (Taz) has high blood pressure from the high salt
Ticarcillin disodium
Amp
Zosyn
Metronidazole
Nafcillin
Unasyn
Moxi

Question 40

What antibiotic causes Achilles tendon rupture?

Duplicate

Answer 40

Fluoroquinolones

Cipro, levo

Question 41

What antibiotic causes pulmonary fibrosis?

Duplicate

Answer 41

Nitrofurantoin

Question 42

What is the first drug for clostridial myonecrosis (gas gangrene)?

Answer 42

UTD: IV penicillin + IV clindamycin or tetracycline
combination of penicillin and clindamycin is the most favorable

Notes say Pen G.

Other drugs that cover c.perfringens (anaerobic GPR): penicillin, clindamycin, tetracycline, chloramphenicol, metronidazole, and a number of cephalosporins

C. perfinges. Infxn of muscles/tissue under deep fascia, sx dedridement.

Question 43

When is the optimal time for secondary wound closure?

Answer 43

4 days after institution of wet/dry dressing

Question 44

What is first line inpatient treatment for neutropenic fever?

Duplicate

Answer 44

NCCN 6/23:
Inpatient therapy: M PICC

• Meropenem (category 1)
• Piperacillin/tazobactam (category 1)
• Imipenem/cilastatin (category 1)
• Cefepime (category 1)
• Ceftazidime (category 2B)

Outpatient PO options:
- Ciprofloxacin plus amoxicillin/clavulanate (category 1)
- Levofloxacin
- Moxifloxacin (category 1)

Question 45

What role does Clindamycin play in the treatment of necrotizing fasciitis

Answer 45

Clindamycin: antitoxin and other effects against toxin-elaborating strains of beta-hemolytic streptococci and S. aureus

Question 46

How does acyclovir work?

(Duplicate)

Answer 46

Synthetic purine nucleoSIDE analog substrate specific for HSV and VZV-specified THYMIDINE KINASE (which adds phosphate). Then acyclovir triphosphate stops replication by
1) competitive inhibition of viral DNA POLYMERASE,
2) incorporation into and termination of growing viral DNA chain,
3) inactivation of viral DNA polymerase

UTD:
Acyclovir is phosphorylated and inhibits DNA synthesis and viral replication by competing with deoxyguanosine triphosphate for viral DNA polymerase and is incorporated into viral DNA.

Question 47

Besides flagyl and Clinda, which antibiotics has the best anaerobic coverage?

Answer 47

CAMP SCUM

Clindamycin
Augmentin [also Timentin (ticarcillin/clavulanate)]
Metronidazole
Pip/Tazo

Second Gen Cephalosporins (Cefoxitin/Cefotetan)
Carbepenems (Imimpen/Meropenem/Ertapenem)
Unasyn
Moxifloxacin/Gatifloxacin

Question 48

When could you use only oral vanco to tx c.diff?

(Related Qs are test questions)

Answer 48

initial episode of nonsevere or severe CDI

Question 49

How can you treat the initial episode of nonsevere or severe C. Diff?

Answer 49

Options:
- Oral Fidaxomicin
- Oral Vancomycin

• For nonsevere disease, alternative regimen if above agents are unavailable: oral Metronidazole

Question 50

How do you treat the first recurrent episode of c diff?

(Related Qs are test questions)

Answer 50

• oral Fidaxomicin + once IV Bezlotoxumab during standard antibiotic regimen
  Or
• oral Vancomycin + once IV Bezlotoxumab during standard antibiotic regimen

Bezlotuxumab- IgG MAB against toxin B

Question 51

How do you treat the second or greater recurrent episode of c diff?

(Related Qs are test questions)

Answer 51

• oral Fidaxomicin + once IV Bezlotoxumab during standard antibiotic regimen
  Or
• oral Vancomycin + once IV Bezlotoxumab during standard antibiotic regimen
  Or
• oral Vancomycin followed by rifaximin + once IV Bezlotoxumab during standard antibiotic regimen

Or for 3rd or greater recurrence, consider fecal microbiota transplantation (FMT). Consider suppression with PO vanc

Question 52

How do you treat Fulminant c diff?

(Related Qs are test questions)

Answer 52

FYI: Fulminant disease is supported by the following clinical data: Hypotension or shock, ileus, megacolon

Absence of ileus:
- oral vancomycin + IV metronidazole

If ileus is present:
- same tx as non-ileus, but consider addition of the following (JS)
- rectal fecal microbiota transplantation (FMT)
OR
- Rectal vancomycin

Question 53

What is the best outpatient empiric antibiotic regimen for community acquired pneumonia?

Answer 53

Amoxicillin or amoxicillin-clavulanate target S. pneumoniae.
Add macrolide (eg azith) or doxycycline to target atypical pathogens.

empiric regimens target Streptococcus pneumoniae, Haemophilus influenzae, and atypical pathogens (ie, Mycoplasma pneumoniae, Legionella pneumophila, and Chlamydia pneumoniae

Question 54

What are the best empiric antibiotics for healthcare acquired pneumonia?

Answer 54

Low MDR risk options:
●Piperacillin-tazobactam
●Cefepime
●Levofloxacin

High MDR risk options:

ONE of the following:
●Piperacillin-tazobactam
●Cefepime
●Ceftazidime
●Imipenem
●Meropenem
PLUS one of the following:
●An aminoglycoside:
•Amikacin
•Gentamicin
•Tobramycin

FYI: Hospital-acquired (or nosocomial) pneumonia (HAP) is pneumonia that occurs 48 hours or more after admission and did not appear to be incubating at the time of admission.

Question 55

What is the best empiric inpatient antibiotic regimen for community acquired pneumonia?

Answer 55

• IV ceftriaxone, cefotaxime, ceftaroline, ertapenem, or ampicillin-sulbactam PLUS macrolide (azithromycin or clarithromycin) or Doxycycline
• Monotherapy with a respiratory IV fluoroquinolone (levofloxacin, moxifloxacin, or gemifloxacin is an alternative for patients who cannot receive a beta-lactam plus a macrolide. But better to combine with a beta-lactam

Usual pathogens: Streptococcus pneumoniae, respiratory viruses (eg, influenza, parainfluenza, respiratory syncytial virus, rhinovirus, and coronavirus disease 2019), less often, Mycoplasma pneumoniae, Haemophilus influenzae, and Legionella spp

Question 56

On Swan-Ganz, how can you tell when is the pulmonary artery catheter is located in the pulmonary artery?

Answer 56

The pressure wave form shows a dicrotic notch

the location of the catheter can be determined by viewing the pressure measured from the tip of the catheter.

• right atrium (RA), the pressure usually averages <5 mmHg and fluctuates a few mmHg.
• right ventricle (RV), the systolic pressure increases to ~25 mmHg and the diastolic pressure remains similar to right atrial diastolic pressure.
• pulmonary artery (PA), the systolic pressure normally is similar to the right ventricular systolic pressure, but the diastolic pressure increases to about 10 mmHg because of pulmonic valve closure at the beginning of diastole.
• balloon Inflated occludes the PA branch. the pressure in the distal port rapidly falls, reaches a stable lower value that is similar to left atrial pressure (mean pressure normally 8-10 mmHg). The pressure recorded during balloon inflation approximates left atrial pressure because the occluded vessel and its distal branches that eventually form the pulmonary veins act as an extension of the catheter.

See: https://cvphysiology.com/heart-failure/hf008

Question 57

If you cannot wedge the pulmonary artery catheter into a branch of the pulmonary artery to occlude it, what other measure can you use to approximate PCWP (pulmonary capillary wedge pressure)?

(Duplicate Q)

Answer 57

pulmonary artery diastolic pressure

• pulmonary artery (PA) diastolic pressure is similar to the pulmonary artery wedge pressure and is similar to left atrial pressure (mean pressure normally 8-10 mmHg).
• accurate as long as no pulmonary HTN exists

See: https://cvphysiology.com/heart-failure/hf008

Question 58

What patients are at risk for Malignant Hyperthermia?

Answer 58

Patients at inherited risk.

Malignant hyperthermia is an autosomal dominantly inherited disorder
Primary gen: ryanodine receptor RYR1 (Chromosome 19)
Others: CACNA1S and STAC3

Question 59

What is the underlying biology of Malignant Hyperthermia?

Answer 59

skeletal muscle hypermetabolism following exposure to halogenated anesthetics, depolarizing muscle relaxants such as succinylcholine, or, occasionally, physiologic stressors.

triggering substances cause uncontrolled release of calcium from the sarcoplasmic reticulum and may promote entry of extracellular calcium into the myoplasm, causing contracture of skeletal muscles, glycogenolysis, and increased cellular metabolism, resulting in production of heat and excess lactate.

Question 60

What are characteristic clinical findings of malignant hyperthermia?

Answer 60

acidosis, hypercapnia, tachycardia, hyperthermia, muscle rigidity (including trismus [lockjaw] during intubation) compartment syndrome, rhabdomyolysis with subsequent increase in serum creatine kinase (CK) concentration, hyperkalemia with a risk for cardiac arrhythmia or even cardiac arrest, and myoglobinuria (red urine) with a risk for renal failure.

hypotension, mottled cyanosis, red urine (myoglobinuria)
Labs – resp and metabolic acidosis, hyperK and Mg, inc lactate and pyruvate

In nearly all cases, the first manifestations of MH (tachycardia and tachypnea) occur in the operating room; however, MH may also occur in the early postoperative period.

High mortality wo appropriate tx

Question 61

What is the antidote for malignant hyperthermia?

Answer 61

prompt treatment with dantrolene sodium

Question 62

What is the treatment of malignant hyperthermia?

Answer 62

Prompt interruption of sgy, cessation of inhalation anesthetics, ext cooling, 100% O2, sodium bicarbonate, diuresis to reduce myoglobinemia and hyperK, dantrolene 1 mg/kg (until sx resolved or 10 mg/kg max dose)

Question 63

What medications are responsible for malignant hyperthermia?

Answer 63

Inhaled medications include:

Halothane.
Desflurane.
Sevoflurane.
Isoflurane.

Intravenous medications include:
Succinylcholine (fast-acting muscle relaxant).

Question 64

What are complications of malignant hyperthermia?

Answer 64

massive skeletal musc edema, pulm edema, DIC, ARF, cerebral edema/seizures

Question 65

What is the best oral treatment for antibiotic-associated diarrhea?

Answer 65

Supportive care, consider loperamide if cdiff ruled out

notes say Metronidazole