shock Flashcards
what is perfusion
the adequate delivery and removal of gasses, minerals and other nutrients to and from body tissues
what factors ensure correct tissue perfusion
- functioning heart
- functioning lungs
- intact vessels
- adequate blood volume
what is shock
an inadequate tissue perfusion doe to acute circulatory failure leading to cellular hypoxia and inability of the cells to utilise oxygen
what are causes of shock
- improper function of the heart
- inadequate fluid
- vessel failure
what causes improper function of the heart
- blunt chest trauma
- tamponade
- drugs
- electrical function
what causes inadequate fluid
- dehydration
- burn injuries
- profuse bleeding
- excessive environmental temperature
what causes vessel failure
- neurological dysfunction causing dilation
- severe allergic reactions
- massive infection
what are the 3 stages of shock
- compensated
- decompensated
- irreversible
what is compensated shock
the body is able to compensate for decreased perfusion
what is decompensated shock
the body is unable to adequately perfuse its cells
what are the compensatory mechanisms in compensated shock
- increase in HR and contraction
- increase in RR to increase arterial oxygenation
- vasoconstriction to improve perfusion to vital organ
what is the SNS response in compensated shock
- increase SNS activity
- increases Na release
what is the RAAS response in compensated shock
- increased RAAS
- increased AgII release
what is the adrenal response in compensated shock
- increased adrenal response
- increase Ad and Na release
what is the pituitary response in compensated shock
- increased pituitary response
- increase ADH
- increase vasopressin release
what are the signs and symptoms of compensated shock
- normal/ increasing HR
- tachypnoea
- normal BP
- normal pupil
- clammy
- pallor
- nausea/ vomiting
- thirst
- restlessness
- anxiety
- agitation
- impending doom
what are the mechanisms on decompensated shock
- BP and vascular tone decreased
- dysfunctioning organs
- anaerobic metabolism = lactic acidosis
- compensatory mechanisms are no longer available
what are the signs and symptoms of decompensated shock
- rapid, weak, thready pulse
- shallow laboured breathing
- decreased BP
- dilated pupils
- clammy hands and feet
- pallor with cyanosis
- extreme weakness
- altered mental status
what are the mechanisms of irreversible shock
- blood shunted from liver, kidney, lung
- brain and heart perfused
- metabolic acidosis
- postcapillary sphincters release stagnant and coagulated blood
- cell death
what are the signs and symptoms of irreversible shock
- bradycardia
- apnoea
- profound hypotension
- fixed and dilated pupil
- unresponsive
what are the different types of shock
- hypovolemic
- distributive
- obstructive
- cardiogenic
what are the types of hypovolemic shock
- haemorrhagic
- non-haemorrhagic
what are the types of disruptive shock
- septic
- anaphylactic
- neurogenic
what causes hypovolemic shock
- loss of blood or bodily fluids
- diminished COP and inadequate O2 delivery
- causes low cardiac output
what causes haemorrhagic shock
- traumatic injuries
- dissected aortic aneurysm
- ectopic pregnancy
- GI bleeding
what are the results of haemorrhagic shock
O2 carrying capacity diminished as RBCs are depleted
what are causes of non-haemorrhagic shock
- vomiting
- diarrhoea
- significant burns
what are the signs and symptoms of hypovolemic shock
- increased RR
- tachycardia
- weak thready pulse
- hypotension
- cool clammy skin
- thirst
- oliguria
- mental status deterioration
what is obstructive shock
when blood flow in the great vessels or heart is occluded
what are the causes of obstructive shock
- acute pericardial tamponade
- massive pulmonary embolus
- tension pneumothroax
what are the signs and symptoms of obstructive shock
- tachypnoea
- tachycardia
- shortness of breath
- hypotension
- cyanosis
- anxiety
what is disruptive shock
inadequate volume of blood to fill vascular space due to an increased vascular capacity
- capillary leakage into extravascular and interstitial spaces
what are the cardiac effects of disruptive shock
- decreased PVR
- decreased preload
- decreased COP
what is septic shock
- an infection causing sepsis
- multiple organ dysfunction syndrome
- massive systemic inflammatory response to infection
what is the pathophysiology of septic shock
- macrophages
- IL, TNFa, NO
- SIRS, leading to sepsis
- vasodilation, hypertension, tissue inflammation
- myocardial depression
- multiple organ dysfunction
what are the signs and symptoms of septic shock
- tachypnoea
- tachycardia
- pyrexial, rigors
- warm
- nausea + vomiting
- high WBC
what is anaphylactic shock
extreme widespread hypersensitivity reaction
what is the pathophysiology of anaphylactic shock
- antigen and antibodies
- histamine, kinins, and PG release
- bronchoconstriction, laryngospasm
- vasodilation
- relative hypovolemia
- decreased COP
- decreased tissue perfusion
what are the signs and symptoms of anaphylactic shock
- cutaneous manifestations (histamines)
- respiratory compromise
- circulatory collapse
- vomiting, nausea + diarrhoea
what is neurogenic shock
result of widespread vasodilation from imbalances between parasympathetic and sympathetic stimulation
what are causes of neurogenic shock
- trauma to spinal cord or medulla
- drugs
- severe emotional stress and pain
what are the signs and symptoms of neurogenic shock
- hypotension
- bradycardia
- pink warm skin
what is cardiogenic shock
decreased cardiac output and evidence of tissue hypoxia with adequate intravascular volume
what are the causes of cardiogenic shock
- MI
- congestive heart failure
- dysrhythmias
- acute valvular dysfunction
- cardiac tamponade
- drug toxicity
what is the pathophysiology of cardiogenic shock
- decreased cardiac output
- compensatory RAAS and catecholamine
- increased SVR and increase blood volume
- increase preload, stroke volume, HR
- increase myocardial O2 needs
- decrease cardiac output and ejection fraction
- decrease tissue perfusion
- impaired cellular metabolism
- myocardial dysfunction
what are the signs and symptoms of cardiogenic shock
- increased RR
- crackles, pulmonary oedema
- bradycardic
- weak thready pulse
- chest pain
- SOB
- MAP <70
what are some complications of shock
- acute renal failure
- acute respiratory distress syndrome
- hepatic dysfunction
- coagulopathies
- multiple organ dysfunction
what cause acute renal failure in shock
lack of perfusion so insufficient oxygenation
what causes acute respiratory distress syndrome in shock
- increased capillary permeability
- fluids build up in alveoli
- impaired ventilation and inadequate oxygenation
what cause hepatic dysfunction in shock
ischemic liver from high liver transaminases and serum bilirubin
what causes coagulopathies in shock
- overstimulation of clotting cascade
- clotting and bleeding occur simultaneously
- clots clog blood vessels and cut off supply
- clotting factors are exhausted, increasing bleeding
what causes multiple organ dysfunction syndrome in shock
- combined failure of 2 or more organs
- mainly seen in septic shock
