What part of the nervous system monitors blood flow and adjusts accordingly?
Autonomic nervous system
How long can the kidneys survive inadequate perfusion before permanent damage occurs?
45 minutes
How long can the brain and spinal cord survive inadequate perfusion before permanent damage occurs?
4-6 minutes
When does the cardiac cycle start and end?
Begins with onset of muscle contraction and ends with the beginning of the next contraction.
Preload
Amount of blood returned to the heart to be pumped out.
Afterloard
Pressure in the aorta or peripheral vascular resistance
(PVR), against which the left ventricle must pump blood.
What governs afterload?
Arterial BP
BP is represented by “
CO x PVR
Mean arterial pressure
Measurement of arterial pressure in the vessels that perfuse the organs and indicate changes b/n CO and PVR
Equation for MAP
Diastolic pressure + 1/3 pulse pressure
Pulse pressure
Calculated by subtracting diastolic BP from systolic BP
Cardiac output
Amount of blood pumped through the circulatory system in 1 minute
CO equation
SV x PR
Relationship between preload, afterload, and SV.
Preload directly affects afterload which in turn affects the SV.
A higher afterload reduces SV.
Frank-Sterling mechanism
If the heart is stretched the muscle will contract more forecully.
What occurs when the heart muscles are stretched?
The heart will contract more forcefully in order to prevent blood from backing up in veins.
Why does the ejection fraction remain the same if the heart muscles are stretched?
Even though the amount of blood being forced through the heart increases, the same amount of blood that was pumped out of the heart is the amount when it returns to the heart. The amount of blood remains the same whether it returning or leaving the heart.
Signs of shock
AMS Tachycardia Cold, moist skin Shallow, rapid breathing Abnormal cap refill Weak, rapid pulse Dull eyes Weakness, fainting, or dizziness Thirst N/V
Class I hemmorrhage
Blood loss : <750 mL % blood loss : 15% HR : minimally elevated or nl Systolic BP : w/in nl limits Capillary refill : w/in nl limits Pulse : w/in nl limits Respiratory rate : 14-20 CNS/mental status : slightly anxious Skin condition : cool, pink Urine output : >30 Fluid replacement : crystalloid
Class II hemorrhage
Blood loss : 750-1,500 mL % blood loss : 15-30 HR : 100-120 Systolic BP : minimal or no change Pulse : narrow Capillary refill : may be delayed Respiratory rate : 20-24 CNS/mental status : mildly anxious Skin condition : cool, moist Urine output : 20-30 mL/h Fluid replacement : crystalloid
Class III hemorrhage
Blood loss : 1,500-2,000 mL % blood loss : 30-40 HR : =>120, thready Systolic BP : hypotensive Pulse : narrow Capillary refill : delayed Respiratory rate : tachypneic CNS/mental status : anxious and confused Skin condition : cool, pale, moist Urine output : diminished Fluid replacement : crystalloid and blood
Class IV hemorrhage
Blood loss : > 2,000 mL % blood loss : >40 HR : tachycardia Systolic BP : hypotensive Pulse : very narrow Capillary refill : delayed Respiratory rate : markedly tachypneic CNS/mental status : confused and lethargic Skin condition : cold, pale Urine output : minimal or none Fluid replacement : crystalloid and blood
When should you remove an impaled object from a wound?
Impaled through the cheek and interferes with airway or the chest and interfered with chest compressions.
Bleeding will almost always stop when the pressure of the dressing ____ arterial pressure.
Exceeds
What dimensions should a triangular bandage be if you are using it as a tourniquet?
4” wide x 6-8 layers thick
How much air should be inflated in an air splint?
50 mm Hg
Hemostatic agent
Adheres to the damaged tissue and either dehydrations the blood or undergoes a chemical reaction that stimulates the natural blood-clotting cascade.
Treatment for epistaxis
Cold compress over bridge of nose while patient leans forward. Rolled gauze can be placed under upper lip as well.
Management of internal hemorrhage
Maintain airway
C-spine if indicated
Administer supplemental oxygen and assist ventilation PRN
Control external hemorrhage
Establish two 18-gauge IVs
Administer 250 mL of nl saline or lactated Ringer solution. Use warm fluids if able.
Keep patient warm
Provide immediate transport
Consider ALS rendezvous for analgesics for pain
How does TXA work?
Reduces fibrinolysis by inhibiting the activation of plasminogen to plasmin, which also reduces cloth breakdown.
Management of hemorrhagic shock
XABC Identify and stop any major bleeding. NPO Splint extremity fx during transport Signs of shock - administer supplemental oxygen and keep warm Establish two 18-gauge IV en route Administer warm isotonic crystalloid of nl saline in 250 mL increments Monitor LOC, pulse, and BP
