Flashcards in Shock States Deck (67)
What is shock?
A complex state of circulatory dysfunction resulting in insufficient oxygen and nutrient delivery to satisfy tissue requirements
Why is early intervention of shock so important?
To interrupt the cycle: decreased blood flow & decreased available oxygen > tissue hypoxia > anaerobic metabolism > metabolic acidosis > irreversible cellular change > cellular death
How are hypotension and shock related?
hypoTN is distinct from shock, but can indicate a late uncompensated shock state
What might cause a dampened wave form on a recently placed arterial line?
1) air in the transducer
2) air in the tubing
3) a clot in the system
What are the clinical signs of shock?
- poor/reduced perfusion
- prolonged cap refill
- respiratory distress
- poor tone
- poor color
- cold extremities (with normal core temp)
- narrow pulse pressure
- A’s & B’s
- metabolic acidosis
- weak pulse
How should adequate UOP in the hypoTN neonate be interpreted?
If BP is low, but UOP is WNL, aggressive intervention may not be necessary; renal perfusion is not adversely affected
* exception: infant with septic shock and hyperglycemia with osmotic diuresis
How can a history of birth asphyxia inform your interpretation of hypoTN?
Birth asphyxia may be a/w myocardial dysfunction and may indicate cardiogenic shock
What influences CO?
HR x SV
How does a neonate affect their CO?
Neonates have limited myocardial compliance, and therefore, can increase their output by increasing their HR
What factors negatively affect cardiac output?
- decreased preload
- increased afterload
- decreased myocardial contractility
- electrolyte, mineral or energy imbalances
What is preload?
the end diastolic volume at the beginning of systole (accounted for by the "stretch" of the ventricles caused by volume of blood that returns from venous circulation)
Why does a decreased preload negatively affect your CO?
With decreased venous return, you don’t have enough blood to push out for systemic perfusion
What is afterload?
ventricular pressure at the end of systole (Ejection stops, and systole is complete- because the ventricular pressure developed by the myocardial contraction is less than the arterial pressure. This determines the end-systolic volume (ESV).
Why does increased afterload negatively affect CO?
Increased systemic resistance is difficult for the heart to pump against and therefore, systemic perfusion is limited
Why does decreased myocardial contractility negatively affect CO?
If myocardial ctx is poor or ineffective, systemic perfusion will be inadequate
What electrolytes have a significant on cardiac function?
What are the different types of shock states?
What is included in the term distributive shock?
What should be considered in differential of shock v. inborn error of metabolism?
Some inborn errors resulting in hypoglycemia or hyperammonemia can mimic the presentation of shock (ex: galactosemia, maple syrup urine disease, etc..)
What is the most common form of shock in the neonate?
What is hypovolemic shock the result of?
Inadequate blood volume
What is the etiology of hypovolemia in the neonate?
- antepartum hemorrhage
- postpartum hemorrhage
- non-hemorrhagic losses
What conditions create a hypovolemic state secondary to antepartum hemorrhage?
1) placental hemorrhage (abruptio placentae & placenta previa)
3) Fetomaternal hemorrhage
4) Difficult delivery (often a/w asphyxia)
5) Umbilical cord injury
6) Birth injuries (spleenic and hepatic rupture)
What conditions create a hypovolemic state secondary to postpartum hemorrhage?
1) coagulation disorders (DIC, coagulopathies)
2) vitamin K deficiency
3) iatrogenic (ex: loss of arterial catheter)
4) adrenal hemorrhage
5) ICH (subdural or subgaleal)
6) pulmonary hemorrhage
7) circumcision wound
What conditions create a hypovolemic state secondary to non-hemorrhagic losses?
1) umbilical cord obstruction (cord, true knot, entanglement)
2) insensible water loss
3) diuretic use
5) heat stress
6) vomiting/ diarrhea
7) GI abnormalities
What increase the risk for a subgaleal hemorrhage?
The likelihood of tearing the emissary vein is increased with a spontaneous, instrument assisted delivery (especially vacuum)
Why are fluid boluses not effective in correcting hypoTN in the septic neonate?
With an infx, endotoxins are released from invading organism affecting the integrity of the capillary wall. The resultant severe capillary leak permits fluid to seep into the interstitium.
What is cardiogenic shock?
Inadequate tissue perfusion secondary to myocardial dysfx and implies primary failure of the heart as a pump
What is the etiology of cardiogenic shock?
1) severe intrapartum or postpartum asphyxia
2) metabolic and/or electrolyte imbalances
3) congenital heart defects
5) PPHN and severe RDS
7) Arrhythmias/ dysrhythmias
8) Infectious agents
9) Hypoxemia and/or metabolic acidosis