Shock

 

Shock is not a diagnosis but rather a description.

Recognize shock, respond to it, and

Over 50% of people in an ICU are in shock. Over 1 million/year in ED.

Mortality is 90% for cardiogenic shock, but is 1% of anaphylactic shock.

Shock is the inadequate supply of oxygen and nutrients for basic homeostasis at the cellular level, leading to systemic organ hypoperfusion, usually due to hypotension. It can lead to massive cell injury and death. It is a medical emergency.

Inability of CV system to provide

 

 

 

Types of Shock

shock-e

 

volume

flow problems

distribution/ultilization problems

 

hypovolemic shock describes a loss of blood. It can result from hemorrhage, poor fluid intake. Assess for external blood loss over ALL the patient's body. Internal bleedng is of critical importance. Other causes include burns, peritonitis, pancreatitis, and massive diarrhea.

Hypovolemic shock cannot follow intracranial bleeding.

 

anaphylactic: type I hypersensitivity

 

cardiogenic shock: reduced cardiac output. Most common cause is MI; look for signs and symptoms, ECG, labs

septic/distributive shock: Decreased systemic vascular resistance from toxin release

 

 

obstructive shock: decreased cardiac output as a result of obstruction to flow. Common causes include PE, tamponade, tension pneumothorax, and status asthmaticus.

 

spinal/neurogenic/vasomotor shock: patient is pink and warm following circulatory collapse.

 

hypoglycemic:

 

cellular toxin: cyanide, carbon monoxide.

endocrine - hypoglycemic

 

 

Approach to Shock

  • Physical Exam
  • Diagnosing Shock
  • Further Investigations
  • Differential

Physical Exam

anxiety, confusion, air hunger, diaphoresis, tachycardia at rest, hypotension

Monitoring blood pressure and organ perfusion is of critical importance.

Follow the vitals

 

Mentation will be initially begins with agitation as epinephrine is dumped. This is followed by depressed.

Respiratory rate is increased due to sympathetic tone and respiratory compensation for metabolic acidosis.

  • severe respiratory distress can be seen with pneumothorax or pulmonary embolism

Blood pressure is decreased (<90 mmHg)

Heart rate increased and feeble

arterial pH: decreased

urine output: decreased; kidneys are one of the first things to experience hypoperfusion

 

Diagnosing Shock

Early shockL inc HR, narrow pulse pressure, anxiety, peripheral vasoconstriction

 

High output shock

Low output shock
  • temperature
  • heart sounds
  • diastolic BP
  • pulse pressure
  • nail beds
  • extremeties
  • WBC
  • site of infection
  • increased or decreased
  • crisp
  • decreased
  • increased
  • rapid
  • warm
  • increased or decreased
  • yes
  • normal
  • muffled
  • minimally decreased
  • decreased
  • slow
  • cool
  • normal
  • no

 

 

cardiogenic shock

hypovolemic shock
  • JVP
  • S3, S4, gallop
  • crackles
  • CXR
  • clinical context
  • increased
  • yes, yes, yes
  • yes
  • CHF, large heart
  • angina, EKG
  • decreased
  • no
  • no
  • normal
  • hemorrhage, dehydration

 

High output hypotension

  • lungs, lines, gut, urinary tract
  • sinusitis, endocarditis, pancreatitis

sepsis: 1/3 mortality. Incidence is increasing, while

 

traumatic non-hemorrhagic shock

  • tamponade, tension pneumothorax

tamponade: sub-xyphoid

Further Investigations

A pulmonary artery catheter can be used to directly measure cardiac output and pressure in right atrium and ventricle, as well as pulmonary artery and capillary wedge pressure. These values can be used to calculate important parameters to determine cause of shock.

However, there is some question about the true utility of this very dangerous procedure.

 

CBC (baseline); hgb and WBC not helpful at the time

blood group and screen

blood glucose

ethanol level

 

chest X-ray - some diagnoses, ie pulmonary edema and tension pneumothorax, are clinical diagnoses and should not depend on diagnostic imaging.

Hypovolemic shock in the setting of blunt trauma can result from internal bleeding into a number of places - pleural space, thigh, pelvis, and abdomen. A physical exam will rule out femur or pelvic fracture, and a CXR will reveal a hemothorax. Accordingly, CT, followed by surgical exploration of the abdomen, should be carried out if no other potential causes of hypovolemic shock are found.

 

ECG in context of cardiogenic shock

Differential

  • thyroid storm
  • liver failure
  • pancreatitis
  • AV ifstula
  • trauma
  • paget's disease
  • analynoss
  • adrenal insufficiency

 

 

 

Managing Shock

The most important strategy is to quickly gain IV access and aggressively replace volume. Normal saline is often sufficient, but colloids can also be used in situations of severe hypovolemia. People at risk of heart failure should be gingerly treated with IV fluids and given ionotropes (dopamine, dobutamine) to increase perfusion.

 

resuscitate and stabilize patient before sending for many tests

LOC and BP are the LEAST sensitive

urinary output is likely the ebst indicator of adequate fluid resuscitation (0.5 ml/kg/hr)

Reassess constantly.

A central line can help deliver fluids and drugs, while an arterial line will allow for constant blood pressure monitoring.

 

Treat according to etiology. In cardiovascular shock, ionotropes can be used to increase output.

 

Sepsis should be treated with antibiotics and drainage of any infected spaces. Give an effective antibiotics within 1 hour. A decrease in survial of % with every ensuing hour.

 

Obstructive shock should be evaluated for potentially reversible blockages, as in the case of massive PE. Treatment with thrombolytics can be useful in this situation.

Shock + trauma = surgeon

 

Airway

Breathing: decrease work of breathing

Ca: circulation optimization

Cb: control oxygen consumption

D: deliver oxygen adequately

E: extraction: rule out cyanide, metHgb

 

Fluid recusitation

Pathophys

compensation: increased HR