Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Surgery > Critical Care > Flashcards

Critical Care Flashcards

1
Q

What determine tissue perfusion?

A

1) CO = SV x HR
2) SV = Preload x contractility
2) SVR = (MAP - CVP)/CO
3) BP = CO x SVR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Hypovolemic shock

A

Reduced venous return, pump is working

Low preload. Low CO

Bleeding, vomiting/diarrhea, and third spacing (burns, bowel obstruction, pancreatitis)

Tachy, ortho hypo, cool skin

Will become hypotensive, low pulse pressure, confused, cold clammy skin due to clamping down of peripheral vessels via increased sympathetic tone

in trauma, assume shock is hypovolemic until proven otherwise

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

First vital organ to succumb to shock?

A

kidney - in hypovolemic or cardiogenic ( the cold shocks)

Blood shunted away from constricted renal arteries

CRUCIAL to monitor for renal failure. A good urine output is a great sign that treatment is working

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What factors suppress the tachycardic response in hypovolemia?

A

Beta blockers

Athletes

Damage to autonomic nervous system (spinal shock)

Never use dextrose-containing solution for resuscitation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

SIRS criteria

A

2+ of following:

Temp > 38C or 90
RR > 20 or PaCO2 12 or 10% bands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Sepsis

A

Identifiable source of infection + SIRS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Severe sepsis

A

Sepsis + organ dysfunction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Septic shock

A

Sepsis + cardiovascular collapse (requiring vasopressor support)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What kind of bacteria are notorious for causing septic shock?

A

gram-negative bacteria

E Coli
Kleb
Pseudomonas

Top 3 gram positives are:
Staph aureus
Enterococcus
Coag-neg staph

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

HR issues leading to shock

A

too slow

too fast (not enough time to fill)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Preload issues leading to shock

A

More blood into heart = more blood out

Volume down
Hemorrhage
Obstruction (tension pneumo, pericardial tamp)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Contractility issues leading to shock

A

HF

MI or myocardial contusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

SVR and shock

A

Massive vasodilation - sepsis/anaphylaxis

Spinal trauma (ANS is lost)

Anesthetics

ANS dysfunction (elderly diabetic)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Neurogenic shock

A

CNS injury causing disruption of sympathetic system, resulting in unopposed vagal outflow and vasodilation.

Hypotension and bradycardia (absence of reflex sympathetic tachy and vasoconstriction)

Usually secondary to spinal cord injury of cervical or high thoracic region

Tx = IVFs - helps to place patient in trendelenburg

Vasopressors - used early if patient unresponsive to fluids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

End points of resuscitation for shock of any etiology

A

Normalization of lactate (marker of O2 debt), base deficit, pH

Normalization of mixed venous O2 sat (marker of O2 delivery and extraction) and CO

Urine output (marker of renal perfusion)***

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Swan Ganz

A

Measure PCWP (preload) - normal 6-12 - reflecting pressure in LV

If pump is failing, you’ll see increased wedge

Risks = infection, arrhythmia, injury of pulmonary artery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Mixed venous O2 sat

A

% of O2 bound to hemoglobin in blood returning to heart

It’s the amount of O2 left over after tissues remove what they need

Normal = 60-80%

Low = CO isn’t high enough to meet tissue O2 needs

BUT

Rise in setting of increased lactate means we’re going to anaerobic (late septic shock or in cell poisoning)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Side effects of pressors

A

If B1 stimulation - arrhythmia

If B2 stimulation - vasodilation therefore hypotension

19
Q

The alpha agonists

A

Phenylephrine, methoxamine (a1 > a2)

Clonidine, methylnorepinephrine (a2 > a1)

20
Q

The mixed alpha and beta agonists

A

Norepi a1=a2; B1> B2

Epi a1=a2; B1=B2

21
Q

Beta agonists

A

Dobutamine B1 > B2

Isoproterenol B1 = B2

Terbutaline, metaproterenol, albuterol, ritodrine B2 > B1

22
Q

Dopamine agonists

A

Dopamine D1 = D2

Fenoldopam D1 > D2

23
Q

Dobutamine

A

Strong B1 stimulator (ionotropic/chronotropic) wit mild B2 stimulation (vasodilation)

Causes increase in CO and decrease in SVR

Usually used in: Cardiogenic shock

24
Q

Isoproterenol

A

Similar to dobutamine

Strong stim of B1 (ionotropic/chronotropic) and B2 (vasodilation)

Increased CO and decreased SVR

Use: Cardiogenic shock with bradycardia

25
Q

Milrinone

A

Phosphodiesterase inhibitor, which results in increased cAMP. This has positive ionotropic effects on heart and also vasodilates

Increased CO and decreased SVR

Use: HF/Cardio shock

26
Q

Dopamine

A

Different actions depending on dose

1) Low dose (1-3ug/kg/min) = renal dose. Stimulates dopamine recepters (dilates renal vessels) and mild B1 stim

Use: None

2) Intermed dose (5-10) = cardiac dose. Stimulation of dopamine receptors, moderate stim of B1 (heart ionotropy/chrono) and mild a2 (vasoconstriction)

Result = Increased CO
Use = cardiogenic shock

3) High dose (10-20). Stim D, B1, and strong a1 (vasoconstict)

Result = Big increase in SVR
Use = septic shock (replaced by norepi)
27
Q

Norepinephrine

A

Strong stim of a1 (vasoconstrict), moderate B1 (heart ionotrope/chrono)

Result: higher SVR and higher CO
Use = septic shock

28
Q

Epinephrine

A

Strong stim of B1 and B2. Also A1 and A2

Result = Increased SVR +/- Increased CO, bronchodilation

Use = Anaphylaxis, septic shock, cardiopulmonary arrest

29
Q

Phenylephrine

A

Strong stim of A1 (vasoconstrict)

Result = Increased SVR

Use = septic shock, neurogenic shock, anesthesia-induced hypotension

30
Q

Indications for intubation

A

Airway protection (GCS

31
Q

Complications of mechanical ventilation

A

Ventilator-associated pneumonia

Barotrauma and tension pneumo

Decreased venous return (preload) and CO

32
Q

Ventilator settings

A

Must define mode (AC, IMV, PS, CPAP)

RR (10-20)

TV (for AC or IMV only) - usually 400-600cc (6-8cc/kg)

FiO2 - always start at 100% and go down. Maintain the pulse ox >90%. Keep FiO2 below 60% to minimize oxygen-induced free radical injury

33
Q

What are some strategies to improve oxygenation on a vent?

A

Increase FiO2

Increase PEEP

34
Q

What happens when you change minute vent?

A

Increased minute vent: lowers PCO2 and increases pH

PCO2 is marker of ventilation
PO2 is marker of oxygenation

35
Q

Causes of failure to wean off vent

A

1) Anxiety/agitation
2) Drugs (sedatives)
3) lytes (low phosphate)
4) Diaphragm dysfunction (neuromuscular dysfunction)
5) Hypothyroidism/malnutrition
6) Excess CO2 production (overfeeding)

36
Q

What is a potential problem of PEEP?

A

Hypotension

Decreases preload

37
Q

CPAP

A

Noninvasive vent that applies constant positive pressure with no variation in breathing cycle

Keeps inspiratory airway pressure above atmospheric w/o increasing work of breathing

Patient must breathe on own

Can be used to help avoid intubation. Mode of choice for OSA

38
Q

Synchronized Intermittent Mandatory Ventilation

A

Patient breathes on own, plus receives a preset rate of MV synchronized to and delivered with patient’s breath.

Pressure support is often added to spontaneous breathing (gives Pt initial boost of pressure to overcome airway resistance)

39
Q

Assist-control

A

Each breath initiated by the patient triggers machine to deliver set tidal volume (volume control) or set peak inspiratory pressure (pressure control)

A set volume/pressure is given a set number of times per minute even if patient is breathing less than the preset rate

40
Q

Pressure support

A

Each breath started by patient triggers machine to deliver an initial boost of pressure with variable flow of air into lungs. Patient determines rate, duration of inspiration and tidal volume

Good mode for weaning

41
Q

Causes of ARDS

A

1) Direct lung injury
- pneumonia
- aspiration
- near drowning

2) Indirect
- Sepsis (#1 of all causes)
- Massive transfusion
- severe trauma, burns, toxins
- pancreatitis

42
Q

Diagnostic criteria for ARDS

A

1) Bilateral fluffy infiltrates on CXR (3 out of 4 lung fields)
2) PaO2/FiO2 ratio

43
Q

ARDS

A

Acute lung injury due to inflammatory process in both lungs causing increased permeability of capillaries and severe V/Q mismatch.

Disease of altered lung compliance

Tachypneic and hypoxic with b/l crackles on exam

44
Q

Management of ARDS

A

Intubate

Treat underlying cause, esp infections

Low tidal volume ventilation (6-8cc/kg)

PEEP often used to improve gas exchange and keep lungs open at relatively low volumes

FiO2 kept at less than 60% to avoid free radical injury

Surgery (27 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions