Critical Care - Shock Flashcards
What is shock?
is a syndrome condition resulting from inadequate tissue perfusion and impaired cellular metabolism leading to cell dysfunction, cell death and organ failure. Cells experience hypoperfusion since the demand for oxygen and nutrients are deprived.
Decreased tissue perfusion can lead to:
hypoperfusion > impaired oxygen and glucose delivery > increasing cellular demand (oxygen and nutrients) and comsumption > impaired cellular metabolism
types of shock
hypovolemic
cardiogenic
obstructive
distributive
what is hypovolemic shock
caused by inadequate blood circulation volume or intravascular volume
oxygen delivery is impaired since RBC volume is decreased which carries oxygen
causes of hypovolaemic shock
non-haemorrhagic (not bleeding) - fluid shift (oedema) and severe dehydration (vomiting, diarrhoea and burns)
haemorrhagic (bleeding) - trauma, GI bleed, postpartum (after giving birth)
hypovolaemic shock transitions
decreased circulating volume > decreased venous return > decreased cardiac output > HYPOTENSION > decreased tissue perfusion > impaired cellular metabolism
S&S of hypovolaemic shock
HR - Tachy (compensates to increase blood flow)
Pulse - weak and thready
BP - hypotension
CO - decreased
CVP - decreased
SVR - increased due to vasoconstriction
O2 sat - low (decreased tissue perfusion)
Skin and Temp - cyanotic, cool and pale skin. cap refill is > 3 secs
oliguria
confused and agitated mental state (decreased blood circulation in the brain)
nursing treatments and intervention for hypovolaemic shock
Fluids and blood replacement
- crystalloids (normal saline) and colloids (albumin) if non-hemorrhagic
- RBCs or blood products for hemorrhagic
encourage fluids
what is cardiogenic shock?
-caused by inadequate cardiac pump function leading to low CO and SV or HR
-heart cannot pump enough blood to meet normal tissue perfusion
-caused by myocardial damage
-blood volume is adequate, however, the heart pump function is impaired causing fluid accumulation in the lungs (pulmonary oedema)
cardiogenic shock transitions
- decreased CO > compensatory RAAS (renin angiotensin aldosterone system) > increased blood volume > increased preload, SV and HR > systemic and pulmonary oedema > dyspnea
- decreased CO > compensatory catecholamine (neurohormone) > increased SVR, preload and HR > increased myocardial oxygen demand > decreased CO and EF (ejection fraction) > decreased tissue perfusion (ischaemia) > impaired cellular metabolism > myocardial dysfunction
S&S of cardiogenic shock
HR - Tachy (compensates to increase blood flow)
Pulse - weak peripheral pulses
BP - hypotension
CO - decreased
CVP - increased
SVR - increased due to vasoconstriction
O2 sat - low (decreased tissue perfusion)
Skin and Temp - cool and clammy skin. cap refill is > 3 secs
oliguria
confused and agitated mental state (decreased blood circulation in the brain) or sense of impending doom
jugular vein distention
chest pain
dyspnea (due to pulmonary oedema)
nursing intervention and treatment for cardiogenic shock
MI - agioplasty (procedure used to open blocked coronary artery)
thrombolytics (medication to dissolve blood clots)
Oxygen therapy
Vasopressors (adrenaline, dobutamine or dopamine) - increase vasoconstriction to increase blood circulation therefore increasing tissue perfusion
Diuretics - decrease heart workload and extra blood volume
pathologic conditions that cause cardiogenic shock
acute MI - cardiomyopathy, sepsis, myocarditis, pericarditis, aneurysm, dysrhythmias (impaired diastolic filling), contusion (blood capillary injury), metabolic abnormalities and papillary muscle rupture
cardiac obstructions due to pulmonary embolism, cardiac tamponade (pressure in the heart due to fluid accumulation between heart muscle spaces and pericardium), valvular disorders, tumours and arterial wall ruptures or defects
what is obstructive shock?
- CO is decreased as circulation is blocked into the heart and its vessels
cause of obstructive shock
-pulmonary embolism (blocked pulmonary artery)
-tension pneumothorax (accumulation of air in the pleural cavity causing pressure in the lungs)
-pericardial tamponade (accumulation of fluid around the sac of the heart)
-abdominal compartment syndrome (increased pressure in the abdomen that restricts blood flow)