Wednesday, November 19, 2008

Shock

A concise listing of things to know about shock, hopefully to be updated frequently.

Shock is defined as inadequate perfusion to meet the needs of tissue metabolism.

Shock can be compensated or decompensated.

Decompensated shock is defined as shock plus systolic hypotension, or
IF BP is unmeasurable, defined as absent distal pulses, prolonged capillary refill, cool extremities, tachycardia, altered mental status (decreased level of consciousness/responsiveness)

Maximum allowable heart rates.

newborn-to 3 months- 85-205.
3 months to 2 yrs- 100-190.
2 yrs to 10 yrs 60-140.
>10 yrs 60-100

MINIMUM acceptable blood pressures
below 12 hours of life and less than 1 kg of weight. 39 systolic.
12 hours of life, 3 kg neonate- 50 systolic
neonate- 96 hours of life- 60 systolic.
Infant- 1 month to 1 year- 70 systolic.
child from age 1-10 =[70 + (2x age in years)]
child age 10 plus= 90 systolic

Criteria for dehydration in children.
minimal (<5%)dry MM, plus or minus tachycardia plus or minus decreased UO.
there will be NO depressed fontanelle, sunken eyeballs, abnormal turgor, cap refill prolonged, weak pulses, hypotension, hyperpnea, altered mental status, or acidosis.

moderate (5-10)positive for dry mm, tachy, depressed fontanelle, sunken eyeballs, decreased uo, PLUS or MINUS turgor, altered, acidosis.
severe (>10) requires weak peripheral pulses, hypotensions, hyperpnea, altered mental status, acidosis, high urine sp grav.

class 1,2,3,4 hemorrhage
class 1-
up to 750 mL blood loss, pulse less than 100, normal BP, normal or increased pulse pressure, rr 14-20, UO >30 mL/hr (0.5 ml/kg), slightly anxious mental status, replace with 3:1 crystalloid:blood.

class 2-
up to 1500 mL blood loss, pulse >100, normal BP, decreased PP, RR 20-30,UO 20-30,mildly anxious. replace with 3:1 cystalloid:blood.

class 3-
up to 2000 mL blood, pulse >120, decreased BP, decreased PP, RR 30-40, UO 5-15, anxious/confused, replace with crystalloid and blood.

class 4
>2000 mL blood, pulse >140, decreased BP and PP, RR >35, negligible UO, confused/lethargic, replace crystalloid and blood.

Metabolism generates ATP which keeps biological membranes intact and functioning (brain and cardiac).

ATP can be generated through anaerobic and aerobic metabolism.

Although seemingly logical, ATP cannot be injected directly into a tissue to improve performance, for a variety of reasons. British Journal of Anaesthesia 94 (5): 556–62 (2005)
http://bja.oxfordjournals.org/cgi/reprint/94/5/556

Anaerobic glycolysis does not require oxygen or mitochondria, it occurs in the cytoplasm. It generates lactate and acid as a byproduct, leading to lactic acidemia.

Aerobic metabolism requires oxygen and the electron transport chain of the mitochondria, it takes longer than anaerobic glycolysis.

For perfusion to occur, cardiac output must be maintained, which requires heart rate and stroke volume. CO=HRxSV


trauma activation
ejection from auto
death in compartment
pedestrian thrown or run over
speed > 40 mph
deformity >20 inches
intrusion > 12 inches
extrication >20 min
fall >20 ft
rollover
auto vs pedestrian >5 mph impact
motorcycle > 20 mph or separation of rider and bike.


flail chest
two or more prox long bone fx
amputation proximal to wrist/ankle
pen trauma to head, neck, torso, extrem prox to elbow and knee
open and depressed skull fx
limb paralysis
pelvic fx
combo trauma plus burn
major burn

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