Shock
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Transcript of Shock
Shock : Pathophysiology Shock : Pathophysiology Causes & ManagementCauses & Management
Dr.Anil HaripriyaDr.Anil Haripriya
Assistant Professor SurgeryAssistant Professor Surgery
NHDC & RCNHDC & RC
IntroductionIntroduction ““Rude unhinging of machinery of life’Rude unhinging of machinery of life’
-GrossGross
Inadequate delivery of oxygen and Inadequate delivery of oxygen and nutrients to maintain normal tissue and nutrients to maintain normal tissue and cellular functioncellular function
Clinically accompanied by hypotension Clinically accompanied by hypotension
MAP < 60 mmHg in a previously MAP < 60 mmHg in a previously normotensive personnormotensive person
Types of ShockTypes of Shock
HypovolemicHypovolemic Vasodilatory (Septic)Vasodilatory (Septic) NeurogenicNeurogenic CardiogenicCardiogenic Obstructive Obstructive TraumaticTraumatic
PathophysiologyPathophysiology
Physiologic response to hypovolemia Physiologic response to hypovolemia directed directed at preservation of perfusion to vital at preservation of perfusion to vital organsorgans
- Increase cardiac contractility & - Increase cardiac contractility & peripheral peripheral vascular tone via ANSvascular tone via ANS - Hormonal response to preserve salt & - Hormonal response to preserve salt &
waterwater - Change in local micro circulation to - Change in local micro circulation to regulate regulate regional blood flow regional blood flow
Neuroendocrine Neuroendocrine responseresponse
Mediated via baro & chemo receptors Mediated via baro & chemo receptors which stimulates ANS & HPA axis which stimulates ANS & HPA axis
release of epinephrine & release of epinephrine & norepinephrinenorepinephrine
Hormonal responseHormonal responseHypothalamusHypothalamus
HyperglycemiaLypolysisGluconeogenesisGlycogenolysis
Cortisol
ACTH
CRH
Hormonal responseHormonal response Stimulation of renin angiotensin Stimulation of renin angiotensin system system
Release of ADH to conserve salt & Release of ADH to conserve salt &
waterwater
Cellular responseCellular response Inadequate delivery of oxygen & Inadequate delivery of oxygen & substrates substrates
leads to in oxidative phosphorylation & leads to in oxidative phosphorylation & ATP ATP
generationgeneration
Anaerobic respiration leads to lactic Anaerobic respiration leads to lactic acidosisacidosis
Cellular responseCellular response
Na+,K+ ATP ase activity decrease Na+,K+ ATP ase activity decrease leading to leading to accumulation of Na+ & leak of K+accumulation of Na+ & leak of K+
Cellular gene expression for Cellular gene expression for HSP,VEGF,NO HSP,VEGF,NO synthase & cytokines is also increasedsynthase & cytokines is also increased
Hypovolemic shockHypovolemic shock
M/C form of shockM/C form of shock
Due to loss of blood, plasma, Due to loss of blood, plasma, extravascular extravascular
sequestration sequestration
C/f and severity depends upon amount of C/f and severity depends upon amount of volume lost volume lost
Hypovolemic shockHypovolemic shock
CausesCauses - Trauma - Trauma - Severe dehydration- Severe dehydration - Burns- Burns - Intestinal obstruction- Intestinal obstruction - Perforation peritonitis- Perforation peritonitis
Hypovolemic shockHypovolemic shock
PhasesPhases - Compenseted- Compenseted
- Decompenseted- Decompenseted
- Irreversible- Irreversible
Hypovolemic shockHypovolemic shock
Mild (<20%)Mild (<20%) Moderate(20-Moderate(20-40%)40%)
Severe(>40%Severe(>40%))
Cold Cold extremitiesextremities
CRTCRT
DiaphoresisDiaphoresis
AnxietyAnxiety
Same +Same +
TachycardiaTachycardia
TachypnoeaTachypnoea
OliguriaOliguria
Postural -Postural -hypotensionhypotension
Same +Same +
HypotensionHypotension
Mental status Mental status deteriorationdeterioration
Cardiogenic shockCardiogenic shock Circulatory pump failure in setting of Circulatory pump failure in setting of adequate vascular volume adequate vascular volume
Sustained hypotension SBP < 90 mm Hg Sustained hypotension SBP < 90 mm Hg for at least 30 minutesfor at least 30 minutes
– CI < 2.2 L/min/mCI < 2.2 L/min/m22
– PAWP >15mmHgPAWP >15mmHg
Surgical importance in patients with Surgical importance in patients with chest trauma forchest trauma for
–TamponadeTamponade–Tension pneumothoraxTension pneumothorax
Cardiogenic shock Cardiogenic shock Chest painChest pain
HypotensionHypotension
ArrhythmiasArrhythmias
Beck’s triadBeck’s triad
Vasodilatory shockVasodilatory shock Characterised by peripheral vasodilatation with Characterised by peripheral vasodilatation with hypotension & resistance to T/t with hypotension & resistance to T/t with vasopressorsvasopressors
CausesCauses- Septic shock- Septic shock- Hypoxic lactic acidosis- Hypoxic lactic acidosis- CO poisoning- CO poisoning- terminal stage of cardiogenic & hemorrhagic - terminal stage of cardiogenic & hemorrhagic shockshock
Septic shockSeptic shock
Manifestation of excessive & Manifestation of excessive & inflammatory response of endogenous inflammatory response of endogenous immune mechanismimmune mechanism
Sepsis is SIRS with established focus of infection
Septic shock - severe sepsis unresponsive to continuous fluid infusion and inotropes
Septic shockSeptic shock Gram –ve bacilliGram –ve bacilli
LPS+CD14
TNF
IL-1
IL-6/IL-8
NO/PAF
Neurogenic shockNeurogenic shock
tissue perfusion as a result of loss of vasomotor tone to peripheral arterial beds
Secondary to spinal cord injury from vertebral #
- Hypotension with bradycardia- Warm extremities - Motor and sensory deficit
ManagementManagement
Initially empirical
Air way secured+ oxygenation
Two wide bore lines
I.V. fluids NS/BSS
Catheterisation
Insertion of central venous catheter
Hb, CBC, Blood sugar, urea, creatinine, electrolytes
ABG
Hypovolemic shockHypovolemic shock
I.V. fluid NS/RL 2-3 liters over 15-30 min
If hemodynamic instability persist then start blood transfusion & control on going heamorrhage
Ionotropic like
Dopamine 5-10microgms/Kg/min
Dobutamine 2-20microgms/Kg/min
Cardiogenic shockCardiogenic shock
Conformation of diagnosis by ECG & ECHO
Intubation & mechanical ventilation often required
Avoid fluid overload
Ionotropic support preferably Dobutamine 2-20microgms/Kg/min
USG guided pericardiocentesis
Neurogenic shockNeurogenic shock
Restoration of intravascular volume by crystalloids
Vasoconstrictor
Dopamine > 10microgms/Kg/min
Phenylephrine 0.2-2.9microgms/Kg/min
Septic shockSeptic shock Culture of body fluids
Infuse BSS 500 cc/15min monitor SBP/CVP
Repeat if CVP 8-12mmHg
Goal to have a MAP of 65 mmHg & P < 120/min
If hemodynamic instability persists start vasopressor preferrably Norepinephrine 0.02-0.25microgms/Kg/min
Broad spectrum antibiotic given
Aims of resuscitationAims of resuscitation
CVP of 8-12 mmHg/ PCWP 8-12 mmHg
MAP of > 65 mmHg
Urine output of 0.5ml/Kg/hr
Hb of 7-9 gm%
CI of > 4.2 L/Kg/m2 of BSA
End Points of End Points of resuscitationresuscitation
Resuscitation complete when oxygen debt repaid,tissue Resuscitation complete when oxygen debt repaid,tissue acidosis corrected & aerobic metabolism restored acidosis corrected & aerobic metabolism restored
Systemic ParametersSystemic Parameters
LactateLactate
Base deficitBase deficit
Tissue ParametersTissue Parameters
Gastric tonometeryGastric tonometery
Near infrared spectroscopy Near infrared spectroscopy
ConclusionConclusion Early recognition of warning signs and diagnosis in the reversible phase important for successful management of shock
Hypovolemia and sepsis account for majority of shock in surgical patients
Principles of initial resuscitation same irrespective of type of shock
Ultimate treatment of underlying cause forms cornerstone of management