2. Hypovolemic Shock Flashcards
Hypovolemic Shock is
The critical reduction in the circulating intravascular volume, leading to inadequate tissue perfusion
Most common type of shock:
-Internal causes: third-spacing or pooling in the intravascular compartment
-External causes: hemorrhage, GI or renal losses, burns, excessive diaphoresis
Hypovolemia effects on pulse pressure:
-Systolic decreases, diastolic maintains or elevates;
NARROW pulse pressure
e.g. Baseline is 130/80
Volume loss–>110/80, 100/80, 90/70
Hemodynamics
-Decreased BP
-Decreased pulse pressure
-Decreased Right atrial pressure (CVP)
-Decreased Cardiac output, O2 delivery
-decreased Left atrial pressure (PAOP)
-decreased SvO2
-Increased systemic vascular resistance (SVR)
Everything is decreased except SVR
Treatment of hypovolemic shock
-Identify the etiology and correct it, if possible
-Replace the volume appropriately: “Fill up the tank!”
-Rapid and vigorous volume loading
-Requires at least 2 large bore IV sites
(hemorrhagic); a central line is not necessary but
may assist fluid replacement.
-Use a fluid warmer if >2000 mL of fluids are
administered in 1 hour (ALL fluids for trauma pts)
-Avoid use of vasopressors
-Fluid resuscitation: goal is to maintain O2 delivery (DO2) and O2 uptake (VO2) into tissue and sustain aerobic metabolism.
Fluid resuscitate to clinical targets (e.g., decreased tachycardia, increased urine output)
-Use isotonic fluid: 0.9 NSS or lactated Ringer’s.
Which is better, 0.9 NSS or LR? Advantages and Disadvantages in Table 5-1
see pic
Normal Saline
is an isotonic crystalloid, effects last approximately 40 minutes, then leaves vascular space
Disadvantages – large volumes may lead to hyperchloremic acidosis
Do not give to those with hypernatremia or renal failure
-Has 154 mols Na+ and 154 of Cl-; does NOT contain any K+, Ca++, or lactate
Lactated Ringer’s
is an isotonic crystalloid, effects last approximately 40 minutes, then leaves vascular space
Best mimics extracellular fluid (ECF) minus proteins, recommended resuscitation fluid by the ACS Committee on Trauma
-Has the potential to correct lactic acidosis; yet in severe hypo perfusion, it may promote lactic acidosis due to lactate accumulation
DO NOT give through a blood product transfusion line or to those who should not receive K+ or lactate
-Has 130 mols of Na+, 109 Cl-, 4 K+, 2.7 Ca++, 28 lactate
Resuscitation endpoints
-MAP greater than/equal to 65 mmHg
-CVP ~ 6 mmHg (not well-defined)
-Urine output 0.5 mL/kg/hr
-HR decreased
-Hgb > 7.0 g/dL and coagulation/platelet abnormalities corrected
-Hemoglobin and hematocrit measurements are not
accurate during active blood loss.
Hemorrhagic Shock
The severity of hemorrhagic shock is categorized into 4 classes (Table 5-2)
Class I
Blood loss (mL): Up to 750
Blood loss (% blood vol): Up to 15%
Heart Rate: < 100
BP: Normal
Pulse pressure: Normal or decreased
Capillary refill: Normal
RR: 14-20
Urine output (mL/hr): > 30
Mental status: slightly anxious
Treat with crystalloids
Class II
Blood loss (mL): 750 - 1500
Blood loss (% blood vol): 15-30%
Heart Rate: > 100
BP: Normal
Pulse pressure: Decreased
Capillary refill: Decreased
RR: 20-30
Urine output (mL/hr): 20-30
Mental status: Mildly anxious
Treat with crystalloids
Class III
Blood loss (mL): 1500-2000
Blood loss (% blood vol): 30-40%
Heart Rate: > 120
BP: Decreased
Pulse pressure: Decreased
Capillary refill: Decreased
RR: 30-40
Urine output (mL/hr): 5-15
Mental status: Anxious, confused
Treat with crystalloids + blood
In which class does BP decrease?
BP does not decrease in hemorrhagic shock until Class III, a lost of 1500 - 2000 mL of blood.
Class IV
Blood loss (mL): > 2000
Blood loss (% blood vol): >40%
Heart Rate: > 140
BP: Decreased
Pulse pressure: Decreased
Capillary refill: Decreased
RR: >40
Urine output (mL/hr): scant
Mental status: Confused, lethargic
Treat with crystalloids + blood
