Shockby

Momen Ali Khan

Definition

Shock is a systemic state of tissue hypoperfusion which is inadequate for normal cellular respiration

Symptoms signs Cold clammy skin Tachycardia Palpitation Hypotension Restlessness Decrease urinary output Confusion Tachypnoea Coma

CellularMicrovascularCardiovascularRespiratoryRenalEndocrine

CellularIn shock at cellular level decrease supply of oxygen ( hypoxia) and nutrient supply ( such as glucose)So,

HypoxiaSwitch to anaerobic metabolismIncrease lactic acid production

Systemic metabolic acidosis

Glucose exhausted

Ceasation of anaerobic respiration (So no production of ATP)

Failure of sodium-potassium pumpRelease of intracellular lysosomal autodigestive enzymes

Cell lysisRelease of intracellular potassium and cellular content into

blood

So there release of

AcidPotassiumCellular and humoral content ( complement ,

neutrophil)

Into blood

cre

Microvascular

Hypoxia and acidosis activate complement and prime neutrophil

Endothelium damaged and become leaky

Fluid leak out and causes tissue edema, excerbating hypoxia

Cardiovascular

Decrease preload and afterload

Increase sympathetic activity

Tachycardia and systemic vasoconstriction

Respiratory Metabolic acidosis and increases sympathetic activity

Tachypnea

Renal Decrease perfusion pressuere

Reduced filtration

Decrease urine output

Endocrine

Activation of adrenaline and RAAS axis

Increase release ADH

Vasoconstriction and resorption of water in renal collecting system

Cortisol also causes sodium and water reabsorption

Classification of shock

Hypovolemic shock Cardiogenic shock Obstructive shock Distributive shock Endocrine shock

Due to reduced circulating volume

Causes1. Haemorrhagic2. Non –haemorrhagic

Poor fluid intake – dehydrationExcessive fluid loss-vomiting , diarrhea, urinary loss (diabetes)Third space loss in GIT, interstitial space- e.g. intestinal obstruction, pancratitis

Primary failure of heart to pump blood to tissues

CausesMyocardial infarction Cardiac dysrhythmiaValvular heart diseaseCardiomyopathyMyocardial depression

Reduced in preload due to mechanical obstruction in cardiac filling

CausesCardiac tamponadeTension pneumothoraxMassive pulmonary embolus

Distributive shockEvents in distributive shock

Vascular dilatationLow systemic vascular resistanceInadequate afterloadInadequate organ perfusio

Causes Anaphylaxis ( due to histamine release)Septic shockSpinal cord injury (failure of sympathetic outflow)

Endocrine shockMay present as combination of hypovolaemic,

cardiogenic, distributive shock.

CausesHypothyroidism – cardiac output fall due to low inotropy and

bradycardia.Hyperthyroidism- high output cardiac failureAdrenal insufficiency

O

Compensated shockDecompensationMild shock Modetrate shokSevere shock

Pitfalls Capillary refill- it is not a specific marker. In distributive shock peripheries are warm and capillary refill are brisk.

Tachycardia- may not always accompany shock. Pateint on beta blocker or implanted pacemaker unable to mount tachycardia. Yo ng patient in penetrating trauma with hemorrhage but little tissue damage show paradoxical bradycardia.

Blood pressure – last sign of shock. Young patient and adult are able to maintain blood pressure untill final stage.

ImmediateABCD Management Ensure patent airway adequqte oxygenation

Determine the type, nature of shock, if not possible safer to assume as hypovolemic shock

N-

Fluid therapyAlways start with crystalloid

For exampleHartmann’s solutionNormal saline

Pulse Blood pressureUrine output- normal 1ml/kg/hourOxygen saturation- by pulse oximetry

Some notes

If patient with active bleeding (major trauma, GIT hemorrhage) must control bleeding and fluid resuscitation run simultaneously. Transfused blood if required.

Patient with bowel obstruction – hypovolaemic shock resuscitate adequately before undergoing surgery