Shock : hypovolemic, septic and neurogenic

SHOCK Part II

Bethelhem Berhanu

Shock

CardiogenicHypovolaemic

Anaphylactic

Distributive

Neurogenic

Classification of Shock

Septic

Hypovolemic Shock

• most common • reduced circulating volume Hemorrhagic shock

Non Hemorragic hypovolemic shock

Vomiting DiuresisDiarrhoea Burns

External or Internal

Pathophysiology of Hypovolemic shock

Hypovolemia

↓Venous Return

Multiorgan failure

Organ dysfunction

Perfusion failure &Tissue hypoxia

Hypotension

↓Cardiac output

↓Preload

BP = CO x TPR

CO = SV x HR

Bodily responses

Physiologic responses- sympathetic activity – tachycardia and SVRHyperventilationcollapse of venous capacitance vesselsstress hormonesAttempt to replace intravascular volume loss

The body will prioritize – Brain and heartSeverity ~ magnitude and the rate of fluid loss

“TENNIS STAGING”15,15-30,30-40,40

American College of Surgeons, 1989

Postural Drop

Clinical Manifestations

• Anxiety - lethargy• Tachypnea• Tachycardia – weak, thready pulse• Normal → Orthostatic drop → Hypotension• Delayed Capillary refill• Cool clammy skin• Oliguria• Thirst

Mild (<20% Blood Volume)

Moderate (20–40% Blood Volume)

Severe (>40% Blood Volume)

Cool extremities

Increased capillary refill time

Diaphoresis

Collapsed veins

Anxiety

Same, plus:

Tachycardia

Tachypnea

Oliguria

Postural changes

Same, plus:

Hemodynamic instability

Marked tachycardia

Hypotension

Mental status deterioration (coma)

Treatment principles: Hypovolemic Shock

• control ongoing loss

• rapid reexpansion of the circulating intravascular blood volume

• GOAL: restore blood volume and improve tissue perfusion and oxygenation

Control bleeding• Direct pressure on the site of wound, Gauze• Elevation• Pressure points -• Tourniquets - • Surgical Methods

• Artery forceps (Spencer Well’s forceps)• Ligation• Cauterisation• Splenectomy – splenic rupture, Hysterectomy for post

partum bleeding

Treatment contd.

• ABC … – Supplemental Oxygen – Endotracheal intubation

• Secure a large bore IV line for fluid resuscitation – Median cubital vein, saphenous vein and

sometimes the internal jugular and subclavian veins

– In pediatric patient - intraosseus line

Re-expansion of Intravascular volume

Fluid TherapyCrystalloid solutions –

0.9% saline Ringer Lactate

Colloid solutions – 5% albumin, gelatins, hetastarch 20 ml/kg in 5 – 15 minutes – repeat upto 60 ml/kg Blood transfusion – 1 unit of blood in 20 minutes

>40% of blood loss (class IV) If the patient is anemic ( Hg < 8g/dl)

We may need to supplement fresh frozen plasma and platelates

Treatment contd.

• Improved perfusion : Warmth Strong pulses Better capillary refill improved mental status Lower HR BP – ideally 90+(agex2) higher Urine output.

Septic Shock

• Septicemia - Presence of microbes or their toxins in blood

• Sepsis – Systemic inflammatory response syndrome (SIRS) that has a proven or suspected microbial etiology

• Severe sepsis – Hypoperfusion with signs of organ dysfunction – Lactic acidosis, oliguria etc.

• Septic shock - Sepsis + hypotension (ABP<90 mmHg systolic, or 40 mmHg less than patient's normal BP) for at least 1 hr despite adequate fluid resuscitation;

Sepsis

Severe Sepsis

Septic shock

MODS

Death

Sepsis and organdysfunction, hypoperfusion,or hypotension

Sepsis-inducedhypotension

Septic, contd.• Importance??

– The most common of the distributive types,– The leading cause of Deaths in ICU in the US. – Increasing in occurrence

• Increased life support for high risk patients• Increase in invasive procedures• Growing number of the immunocompromised

– HIV– Chemotherapy

• PREDISPOSING FACTORS - examples–Extended hospitalization–Advanced age–Debilitating illness–Immunodeficiency disorder–Disseminated malignancy

Septic, contd.

Septic, contd.

• Focus of infection– Pneumonia, UTI, Meningitis, skin and soft tissue

infections, GI infections, etc.

• Gram –ve bacteria (70%) – LPS – Lipid A• Peptidoglycan & lipoteichoic acid of gram +ves• Polysaccharide surface of Candida

Septic, contd.

LPS LBP

LPS

ENDOTHELIAL CELL

Bacteria

LPS

LBP LPS

CD 14

MONOCYTE, MACROPHAGESNEUTROPHILS

soluble CD 14

TNF-AIL-1

Cellular chemotaxisEndotherlial injuryActivation of coagulation cascade

Septic, contd.

• The syndrome of septic shock – Systemic vasodilation (hypotension)– Diminished myocardial contractility– Widespread endothelial injury and activation,

causing systemic leukocyte adhesion and pulmonary alveolar capillary damage (ARDS)

– Activation of the coagulation system, culminating in DIC

Septic Shock Hemodynamics

Warm (hyperdynamic) shock

hypotensive

tachycardia

tachypnea

bounding pulse

warm, well perfused extremities

skin flushed, moist

Cold (hypodynamic) shock

hypotensive

tachycardia

tachypnea

narrow, thready pulse

cold, poorly perfused extremities

skin pale, dry

Principles of treatment:Septic shock

• Ventilatory support• IV fluids – crystalloids or colloids - Fill the tank

• Vasoactive agents – Norepinephrine, Dopamine etc.

• Draw blood for culture – before Antibiotics

• Remove septic focus – Resect a gangrenous bowel, Drain an abscess

• Early empirical antibiotic therapy

Neurogenic Shock

• Cause – high spinal cord injury, spinal anaesthesia

• Pathophysiology - Interruption of sympathetic vasomotor input

• extremities are warm• Rx – IV fluids

• norepinephrine or a pure -adrenergic agent (phenylephrine)

Hypovolemic shock

• History – • Trauma• tearing type of chest pain• hematemesis, melena, severe diarrhea

• P/E – Obvious bleeding• Cool clammy skin• sweating• Narrow pulse pressure• Delayed capillary refill• Anxious, confused

Cardiogenic shock

• History - chest pain, shortness of breath, diaphoresis, syncope etc.

• Symptoms of Hypoperfusion plus • Raised JVP • gallop• Rales – Basal creptations • Beck’s triad

Septic shock

• History – Sx of underlying infection• P/E

– Evidences of Infection – Warm extermities– Bounding pulse– Wide pulse pressure– Brisk capillary refill– Obtunded

References • Harrison’s principles of internal medicine-

18th edition• ACS surgery: principles & practice• Mannipal manual of surgery• Robbin’s basic pathology• Shwartz principles of surgery• Davidson’s principles and practice of medicine• World Wide Web

QUESTIONS?