Shock + Nutrition

Question 1

List the 4 main categories of shock.

Answer 1

1. Hypovolemic
2. Cardiogenic
3. Obstructive
4. Distributive

[Can always have mixed shock]

Question 2

DDx - Hypovolemic shock

Answer 2

Hemorrhage (trauma, GI bleeding)
Third space loss of plasma volume (pancreatitis, bowel obstruction, infarction, anaphylaxis)
Diarrhea
Burns

Question 3

DDx - Cardiogenic shock?

Answer 3

Acute MI
Arrhythmia
Acute valvular dysfunction
Ventricular septal rupture
Dilated/end-stage cardiomyopathy
Ventricular aneurysm
LV outflow track obstruction
Myocarditis

Question 4

DDx - Obstructive shock?

Answer 4

Pericardial tamponade
IVC/SVC obstruction
Aortic dissection
Massive PE
Severe pulmonary HTN
Tension pneumothorax

Question 5

DDx - distributive shock?

Answer 5

Neurogenic
Septic
Toxic (OD)
Anaphylaxis
Endocrine (adrenal)

Question 6

Pathophysiology of shock?

Answer 6

All involve circulatory failure leading to inadequate cellular oxygen utilization

Distributive - decreased SVR + altered O2 extraction

All others - low CO -> inadequate O2 transport

Question 7

Calculate MAP

Answer 7

MAP = diastolic pressure + (1/3 pulse pressure) = [CO x SVR] + CVP

Pulse pressure = systolic - diastolic

Question 8

Define each type of shock by warm/cold and wet/dry.

Answer 8

Warm: distributive (bounding pulses, high pulse pressure)
Cold: cardiogenic, hypovolemic, obstructive (weak, thready pulses)

Wet: cardiogenic
Dry: hypovolemic

Question 9

What is the purpose of pulmonary artery catheter?

Answer 9

Measure CO

Question 10

Indications for use of pulmonary artery catheter?

Answer 10

Dx and manage numerous CV illnesses (pHTN, cardiogenic shock, mixed shock, cardiac tamponade, mechanical complications of STEMI

Standard evaluation of patients being considered for heart and lung transplant

Question 11

What is measured by a pulmonary artery cath and how is it used?

Answer 11

RA pressure ~ CVP ~ diastolic RV pressure

Pulmonary artery pressure ~ systolic RV pressure

Pulmonary capillary wedge pressure ~ LA pressure

Calculate CO, SVR, pulmonary vascular resistance

Question 12

Normal range of RA, RV, PA, PCW pressures?

Answer 12

RA: 1-5
RV: 15-30/1-7
PA: 15-30/4-12
PCW: 4-12

Question 13

Pulmonary artery cath findings in cardiogenic shock

Answer 13

Low CO
Increased filling pressures in LA –> elevated PCWP
Elevated SVR
Decreased MVO2

Question 14

Pulmonary artery cath findings in early distributive shock

Answer 14

Increased CO
Decreased SVR
Increased MVO2

Question 15

Pulmonary artery cath findings in hypovolemic shock

Answer 15

Low CO
Inadequate ventricular filling -> low PCWP
Compensatory changes in SVR and MvO2

Question 16

CO = ?

Normal range?

Answer 16

Oxygen consumption (mL/min) divided by (Ca - Cv), where Ca is O2 content of arterial blood and Cv is O2 content of venous blood

4.8-7.3 L/min

Question 17

CI = ?

Normal range?

Answer 17

CO/BSA

2.8-4.2 L/min/m^2

Question 18

SVR = ?

Normal range?

Answer 18

80[(MAP - RA) / CO]

700-1600

Question 19

PVR = ?

Normal range?

Answer 19

80[(PA - PCWP)/CO]

20-130

Question 20

SIRS?

Answer 20

2+ of the following:
-Tachycardia (HR>90)
-Tachypnea (RR>20)
-Fever (T>38) or hypothermia (T<36)
Leukocytosis (WBC>12K), leukopenia (WBC<4K), or bandemia (>10%)
pCO2 32 or less

Question 21

Sepsis?

Answer 21

SIRS + suspected/confirmed infection

Question 22

Severe sepsis?

Answer 22

Sepsis complicated by organ dysfunction

• Thrombocytopenia <100K, DIC, areas of mottled skin
• Capillary refill 3+ seconds
• UOP <0.5mL/kg
• Lactate >2
• Abrupt change in mental status or abnormal EEG findings
• Acute lung injury/ARDS
• Cardiac dysfunction

Question 23

Septic shock?

Answer 23

Sepsis-induced hypotension persisting despite adequate fluid resuscitation

Question 24

qSOFA?

Answer 24

2+ of the following:
RR 22+
Change in mental status
Systolic BP 100 or less

Question 25

What does mixed venous O2 saturation tell us?

Answer 25

End result of oxygen consumption and delivery; helpful in determining adequacy of balance between O2 demand and supply; helpful in interpreting CO

Question 26

Normal O2 delivery and extraction?

Answer 26

O2 delivery ~1 L/min O2 extraction 250 mL/min 75% SvO2

Question 27

How can SvO2 be improved?

Answer 27

Increase delivery of O2 to the tissues (transfusion in theory; dobutamine increases contractility and CO) Decrease O2 consumption (sedation, paralysis, treat fever)

Question 28

Rx shock?

Answer 28

Ventilate (O2) - decrease O2 demand of respiratory muscles, decrease LV afterload by increasing intrathoracic pressure Infuse (fluid resuscitation - crystalloid at 300/30 min) Pump (vasoactive agents)

Question 29

NS vs. LR fluids?

Answer 29

NS can worsen acidosis | LR can negate this due to presence of bicarb

Question 30

First line pressor in septic shock?

Answer 30

Norepinephrine Predominant A1 + modest B1 (vasoconstriction, inotropy) Improves MAP w/little change in HR or CO

Question 31

Second line pressor in septic shock?

Answer 31

Epinephrine Predominant B1 at low doses Predominant A1 at higher doses

Question 32

First line inotrope?

Answer 32

Dobutamine Primarily B1, weak B2 -> increased HR, SV, CO; peripheral vasodilation Preferred inotrope in patients w/myocardial depression associated with septic shock, IN COMBO w/vasoconstrictor

Question 33

Describe hemodynamic profile (CVP, PCWP, CO, SVR, SvO2) for distributive shock

Answer 33

``` CVP: low PCWP (preload): no change CO (pump function): low/normal SVR (afterload): low SvO2 (tissue perfusion): high ```

Question 34

Describe hemodynamic profile (CVP, PCWP, CO, SVR, SvO2) for cardiogenic shock.

Answer 34

``` CVP: high PCWP (preload): high CO (pump function): low SVR (afterload): high SvO2 (tissue perfusion): low ```

Question 35

Describe hemodynamic profile (CVP, PCWP, CO, SVR, SvO2) for hypovolemic shock.

Answer 35

``` CVP: low PCWP (preload): low CO (pump function): low SVR (afterload): high SvO2 (tissue perfusion): low ```

Question 36

Describe hemodynamic profile (CVP, PCWP, CO, SVR, SvO2) for obstructive shock (think massive PE)

Answer 36

``` CVP: high PCWP (preload): normal/high CO (pump function): low SVR (afterload): high SvO2 (tissue perfusion): low ```

Question 37

Basic methods of assessing nutrition status?

Answer 37

Hx: poor eating habits, alcohol abuse, social stressors Exam: BMI, weight loss, thin appearance, temporal wasting Labs - Best acute indicators: retinol binding protein, prealbumin, transferrin - Best overall indicator: albumin

Question 38

Prior to starting TPN, what should be done?

Answer 38

CBC, LFT, BMP, lipid w/triglycerides Place CVC or PICC w/post-placement CXR Nutrition consult

Question 39

Risks of TPN?

Answer 39

TPN metabolized by the liver, so can increase bilirubin, AST, ALT Can cause profound hyperglycemia (insulin often added)

Question 40

Why is enteral nutrition preferred to TPN?

Answer 40

Better immunological function and overall better outcomes than those who are NPO or on TPN (disuse of intestines results in atrophy w/increased infection risk)

Question 41

Risks of enteral nutrition?

Answer 41

Pneumothorax if placed in lung, aspiration, can cause diarrhea + decreased GI motility

Question 42

What should be done if NG or DHT are placed following by acute SOB/hypoxia?

Answer 42

``` CXR Non-rebreather (hastens absorption of pneumo) Pull tube Serial CXRs Chest tube if no improvement ```

Question 43

NG vs. DHT?

Answer 43

NG - easy to place, commonly dislodged, prolonged placement can result in nasal and esopahgeal erosion and sinusitis; can be used for both feedings and suction DHT - dedicated feeding tube, weighted at end, somewhat easier to pass post-pyloric

Question 44

Define refeeding syndrome.

Answer 44

Hypophosphatemia (whole body depletion of phosphorus in the setting of insulin surge) Hypokalemia (shift to anabolism -> increased potassium uptake) Hypomagnesemia Hyperglycemia (glucose intake after starvation suppresses gluconeogenesis through insulin release)

Question 45

Manage/prevent refeeding syndrome?

Answer 45

Slow nutrition intiation over several days Decrease KCals by 50% until lytes are corrected. Check lytes Q12 hours + aggressive repletion Start thiamine and MV Once clinically stable and normal lytes for 24 hours, increase nutrition by 10-20% caloric increments until final requirements are met

Question 46

What should be done if a patient has high residuals with tube feeds?

Answer 46

KUB - obstruction or ileus? (Note that ileus is not a contraindication to TF) Do not immediately start TPN. If ileus - promotility agents like erythromycin and Reglan If aspiration pneumonia - ABX If SBO - stop tube feeds, place NG to suction, initiate TPN.