WEEK 6- SHOCK Flashcards
Shock Definition
- Widespread abnormal cellular metabolism that occurs when the human need for oxygenation and tissue perfusion is not met to the level needed to maintain cell function.
- “Whole-body” response.
- Shock is a “syndrome.”
- Any problem that impairs oxygen delivery to tissues and organs can start the syndrome of shock and lead to a life-threatening emergency
Shock- KEY POINT
Causes and initial manifestations of each type may vary but hypotension and anaerobic cellular metabolism eventually result in the common key features of shock
Features of Shock
***Cardiac output is decreased Increased pulse rate, thready Decreased blood pressure Increased respiratory rate, cyanosis Decreased urinary output* Skin cool to the touch, pale to mottled Nausea, diminished bowel sounds
Types of Shock
Hypovolemic
Cardiogenic
Septic
Distributive
**may have more than one type at the same time
Hypovolemic Shock
- -Occurs when low circulating blood volume causes a mean arterial pressure (MAP) decrease; the body’s oxygen need is not met
- -Commonly caused by hemorrhage (external or internal) and dehydration
Cardiogenic Shock
- Actual heart muscle is unhealthy, and pumping is directly impaired
- Myocardial infarction is the most common cause of direct pump failure
Distributive Shock
- Blood volume is not lost but is distributed to the interstitial tissues where it cannot circulate and deliver oxygen
- Caused by loss of sympathetic tone, blood vessel dilation, pooling of blood in venous and capillary beds, capillary leak
- Ie: anaphylaxis, sepsis
Complex type of distributive shock—
usually begins as a bacterial or fungal infection and progresses to a dangerous condition over a period of days
Sepsis—
widespread infection coupled with a more general inflammatory response, known as systemic inflammatory response syndrome (SIRS), that is triggered when an infection escapes local control
Stage of sepsis and SIRS when multiple organ failure
is evident and uncontrolled bleeding occurs.
Even with appropriate intervention, the death rate among patients in this stage of sepsis exceeds 60%.
Stages of Shock
Initial stage
Nonprogressive stage
Progressive stage
Refractory stage
Initial Stage of Shock
Baseline MAP decreased by less than 10 mm Hg
Heart and respiratory rate increased from the baseline or a slight increase in diastolic blood pressure
Adaptive responses of vascular constriction and increased heart rate
works at the cellular level
Nonprogressive Stage/ compensatory stage
MAP decreases by 10 to 15 mm Hg.
Kidney and hormonal adaptive mechanisms activated
Tissue hypoxia in non-vital organs
Acidosis and hyperkalemia (high potassium)
Stopping conditions that started shock and supportive interventions can prevent shock from progressing
Non-Progressive Stage S & S
Anxiety
Restlessness
Increased thirst (because of low liquids in body)
Tachycardia
Increased RR
Decrease UO
Decrease SBP/increasing DBP (narrowing PP)
Cool extremities
2-5% decrease in O2 saturation
**if stable can stay at this stage for hours
Progressive Stage
Further decrease in blood pressure
Sustained decrease in MAP of more than 20 mm Hg from baseline
Vital organs develop hypoxia
Life-threatening emergency
Immediate interventions are needed
Conditions causing shock need to be corrected within 1 hour of the onset of the progressive stage
COMPENSATORY MECHANISM FAIL
Progressive Stage S &S
**Worsening of S &S *life-threatening* Action needed within 1 hr** Severe thirst, anxiety Sense of impending doom Confusion Rapid, weak pulse Pallor (?) to cyanosis (mucous membranes/nail beds) Cool, moist skin Anuria- increase urine NA and dec in K 5-20% 02 sat drop Labs: low pH, high lactic acid, high K+
Refractory Stage of Shock
Too much cell death and tissue damage resulting from too little oxygen reaching the tissues.
Body can no longer respond effectively to interventions, and shock continues.
Severe hypoxia
Multiple organ dysfunction
Death
profound hypotension
