Shock Flashcards
Shock definition:
Inadequate oxygen delivery to meet metabolic demands… results in… global tissue hypoperfusion and metabolic acidosis
Shock can/ can not occur with a normal BP:
Can
Pathophysiology:
The lack of adequate energy supply leads to a build up of waste products and failure of energy-dependent functions, release of ccellular enzymes, accumulation of calcium and ROS -> cellular injury and cell death
Stages of shock:
- Initial compensated stage - sympathoadrenal system, cortisol secretion, ACTH, vasopressin, RAAS, endothelin and vasoconstrictor production
- Decompensated reversible stage - organ damage symptoms appear - hypotension, hypoxia, tachypnea, oliguria, acidosis, altered mentation
- Decompensated irreversible stage - Multi-organ faliure
Organ response (microcirculation):
Systemic vascular resistance rises - NE acts on a-1 receptors as a VC
Reduced filtration
Organ response (cellular response):
Decreased ATP
Accumulation of H+, lactate
Organ response (neuroendocrine response):
Vasoconstriction
Reduced vagal activity
ACTH release
Increased renin release
Organ response (Cardiovascular response):
Decreased ventricular filling (decreased preload)
Impaired myocardial contractility which reduced SV
Elevated systemic vascular resistance
Organ response (Pulmonary response):
Increased pulmonary vascular resistance (septic shock)
Tachypnoea but restricted ventilation
Atelectasis
ARSD
Organ response (renal response):
Reduced renal blood flow and reduced GFR
Reduced urine volume, oliguria, ARF
Acute tubular necrosis
Organ response (Inflammatory responses):
Activation of coagulation cascade causes microvascular thrombosis
TNF-a
IL-8
Thromboxan A2
Compensation:
- Mobilization of 11L interstitial fluids
- SNS activation
- RAAS activation, ADH secretion
Types of distributive shock:
Septic
SIRS
Neurogenic
Anaphylatic
Drug-/toxin-induced
Endocrine
Mild shock:
Loss of 10-15%
Collapse of subcutaneous vv. of extremities
Patient is thirsty and cold
Moderate shock:
Loss of 20-30%
Mild tachycardia
Narrow pulse pressure
Tachypnea
Anxiety
Oliguria
Drowsy
Confused
Severe shock:
Unconscious
Loss of >40%
Anuria
Rapid pulse
Hypotension
ET Intubation can _____ hypotension
worsen
Shock treatment goals:
BP (MAP>65mmhg)
CVP (8-12mmh2O)
Urine (>0.5ml/kg/hr)
Central venous O2 sat. > 70%, or mxed venous sat. >65%
Maintain Hg>__d/l
10
First step in treatment of shock:
Crystalloids 1000ml or
colloids 300-500ml in 30m
Hypovolemic shock treatment:
Crystalloids
- normal saline or lactate ringers
- up to 2-2.5L
- Consider catecholamines
Sepsis criteria:
HR > 90
RR > 20
WBC >12,000 or <4,000
Sepsis initial treatment:
20-40mL/lg bolus
Cardiogenic shock parameters:
SBP <90mmhg
CI < 2.2L/m/m2
PCWP > 18mmHg
Loss of __% LV function causes clinical shock
40
Intubation will ______ preload
decrease
Anaphylaxis is ___ mediated
IgE
How to distinguish anaphylaxis from anaphylactoid rxn clincally?
You can’t dumbass
Cause of anyphylactoid rxn?
Anasthetics, stings, food, AB
Anaphylactic shock treatment?
0.3mg IM Epi-pen
Repeat every 5-10mins as needed
Caution w/ beta-blockers > HTN due to unopposed alpha stimulation
CV collapse 1mg IV 1:10,000
If refractory, start IV drip
Injury above __ can cause neurogenic shock
T1
In neurogenic shock keep MAP at _______
85-90
For blunt spinal cord injury consider
methylprednisolone
Infusion of one litre of 0.9% NaCl adds ___mL to the plasma volume and ___mL to the interstitial volume
275
825
Crystalloids
Contain electrolytes
First line
25% in plasma, 75% in interstitial volume
short HL: 30-60mins
Colloids:
Large solute molecules do not pass readily from plasma to interstitial fluid
75% expands plasma volume
25% expands interstitial volume
HL 2-4h
Suitable for small-volume rescuscitation
Indications for whole blood:
Hemorrhage (25% or more volume loss)
Exchange transfusion
Patients who bleed after 4 units of packed RBC’s
Indications for packed cell transfusion:
Symptomatic chronic anemia w/o hemorrhage
Acute sickle cell crisis
Cardiac faliure
Acute blood loss
Perioperative anemia
Autologous vs Allogenic blood transfusion:
Autologous - same person
Allogenic - another person
