1 Acute circulatory failure/ cariogenic shock – classification, pathophysiology and managment

Question 1

what is acute circulatory failure

Answer 1

due to reduced CO leads to a severe continuous hypoperfusion and ischemia of vitally important organs,
change to anaerobic metabolism

Question 2

types of acute circulatory failure ?

Answer 2

=hypovolemic shock
loss of 25% of intravasal fluid volume

=cardiogenic shock

=obstructive

=Vasodilative shock (distributive)
Septic shock
anaphylatic shock
neurogenic

Question 3

what causes obstructive shock ?

Answer 3

Cardiac tamponade

Pulmonary embolism

Tension pneumothorax

Constrictive pericarditis

Restrictive cardiomyopathy

Aortic dissection/stenosis

Question 4

what is Cardiogenic shock

Answer 4

reduced function of heart as a pump- reduced CO leading to state of hypotension (less than 90 mmhg) for more than 30 minutes

cardiac index less than 2.2 / l / min / m2

presence of elevated left ventricular filling pressure (Pulmonary capillary wedge pressure - estimate of left ventricular end-diastolic pressure ) more than 18mmhg

signs and symptoms for end organ hypoperfusion-restlessness confusion , cold , oligourea (less than 30ml/hr)

Question 5

what is the clinical appearance of shock?

Answer 5

hypotension

tachycardia

cold ,pale, sweaty skin

confused, even coma GCS 10
́
oliguria
→ due to redistribution of the blood to vitally important organs

weak pulse

cerebral hypoperfusion - cheyne stokes breathing

slow capillary refill

cardiogenic
additional
Chest pain in MI
Palpitations, syncope in arrhythmias

Physical examination might show:
Abnormal auscultatory findings (e.g., S3, S4)
Pulmonary edema, diffuse lung crackles (fine basal crepitations )
Elevated JVP and distended neck veins

Question 6

what is the diagnosis of general shock and cardiogenic ?

Answer 6

heart rate, blood pressure, oxygen saturation

Shock index = pulse rate/systolic blood pressure
> 1 (positive shock index): indicates shock

Catheterize the bladder to assess urine output.

Renal function tests: ↑ BUN and creatinine indicate acute renal failure

Arterial blood gas analysis: lactic acidosis (commonly elevated in septic shock)

blood - increased lactate

pro calcitonin for septic shock ( biomarker that exhibits greater specificity than other proinflammatory markers)

cardiogenic :
ECG: myocardial infarction, cardiac arrhythmias

↑ BNP (or NT-proBNP)

Cardiac markers (e.g., ↑ troponin I, troponin T)

transthoracic Echocardiography: valvular lesions

Pulmonary artery catheterization: to monitor hemodynamic parameters as a guide to therapy
↑ PCWP (> 15 mmHg), can also be ↓
↓ CO
↑ SVR

Question 7

which organs are most vulnerable to shock ?

Answer 7

CEREBRAL

• INTESTINAL WALL MUCOSA
• KIDNEYS
• LUNGS
• LIVER

Question 8

what are the phases in shock?

Answer 8

1) Non-progressive phase (compensation) =
* Peripheral vasoconstriction : cold, clammy extremities increased capillary refill time

• Decreased capillary hydrostatic pressure → increases absorption of interstitial fluids into intravascular space to help maintain blood pressure
• Tachycardia
• Oliguria

2) Progressive phase
* Worsening hypotension

• Hypoperfusion of peripheral tissues → generalized tissue hypoxia → anaerobic metabolism in the underperfused organs → lactic acidosis →
  Worsening tachypnea
• Acidosis, cerebral hypoperfusion → altered mental status
  3) Irreversible phase (stage of decompensation):
• Cerebral hypoxia

*Myocardial ischemia → acute coronary syndrome → decreased cardiac output → Widespread cell necrosis → Release of lysosomal enzymes → further tissue injury
* Bowel ischemia → bacteremic sepsis → worsening of shock
multiple organ failure)

Question 9

what are the compensatory systems?

Answer 9

RAAS
erythropoesis
sympatheticoadrenal systems

Question 10

what is the management of cardiogenic shock in hemodynamically unstable ?

Answer 10

HEMODYNAMICALLY UNSTABLE PATINETS - CARDIOGENIC SHOCK

DRY AND COLD
initial small fluid bolus less than 500 ml - and asses fluid responsiveness , add more if positive - reassessment for volume overload

shock persists =
sBP < 70 mm Hg: norepinephrine

sBP 70–100 mm Hg: dopamine B1 /B2agonist - inotropic effect
dobutamine (more selective beta1 agonist-ionotropic ) -acute heart failure such as massive myocardial infraction
milrinone

WET and cold
inotropic support
if shock persist - vasopressor - NE
once BP is over 90 mmhg - start diuretic

if symptoms persists - refectory acute heart failure

2)

Question 11

what are the causes of cariogenic shock ?

Answer 11

Arrhythmias - VT

ACUTE Myocardial infarction - esp left ventricular

Valve defects / papillary muscle rupture

Heart failure

Cardiomyopathy

Myocarditis

Drugs

Blunt cardiac trauma

Question 12

clinical feature classification of acute heart failure

Answer 12

no evidence of congestion at rest (uncommon) and adequate perfusion = warm and dry

no evidence of congestion (uncommon)and hypoperfursion = cold and dry

evidence of congestion (95 percent patients ) and adequate perfusion = warm and wet

evidence of congestion and hypo perfusion = cold and wet

Question 13

when should we avoid inotropes ?

Answer 13

left ventricular outflow tract obstructions - hypetrophic cardiomyopathy , aortic stenosis

Question 14

hemodynamically stable patients managmnet of ACUTE HEART FAILURE

Answer 14

dry and warm - optimise oral therapy

wet and warm / wet and cold (bp over 90mmhg)
- start diuretics
symptoms persists - refectory acute heart failure