generalidades del shock Flashcards
definition of shock
an abnormality of the circulatory system that results in inadequate organ perfusion and tissue oxygenation
what is the first and second step in the initial management of shock in trauma patients
1st: recognize its presence
2nd: ID probable cause of shock
what is the most common cause of shock in the injured patient
hemorrhage
how is stroke volume determined
preload
myocardial contractility
afterload
how is cardiac output determined
HR (beat/min) x Stroke volume (ml/beat)
what is the earliest measurable circulatory sign of shock in a trauma patient
tachycardia
what is the most effective method of restoring adequate cardiac output and end-organ perfusion
restore venous return to normal by locating and stopping the source of bleeding, along with appropriate volume repletion
T/F. Vasopressors are contraindicated for the tx of hemorrhagic shock
TRUE
they worsen tissue perfusion
T/F. Any injured pt who is cool and has tachycardia is considered to be in shock until proven otherwise
TRUE
how is shock in a trauma patient classified
hemorrhagic or nonhemorrhagic
what does nonhemmorrhagic shock include
cardiogenic shock cardiac tamponade tension pneumothorax neurogenic shock septi shock
chacarteristics of cardiogenic shock
myocardial dysfx can be caused by blunt cardiac injuty, cardiac tamponade, and air embolus, or, rarely a myocardial infarction
characteristics or cardiac tamponade
tachycardia, muffled heart sounds, and dilated, engorged neck veins with hypotension resistant to fluid therapy suggest cardiac tamponade
cardiac tamponade is best managed by thoracotomy
how does a tension pneumothorax develop
when air enters the pleural space, but a flap-valve mechanism prevents its escape
intrapleural pressure rises, causing total lung collapse and a shift of the mediastinum to the opposite side with the subsequent impairment of venous return and fall in cardiac output
the presence of acute respiratory distress, subcutaneous emphysema, absent breath sounds, hyperresonance to percussion, and tracheal shift supports the dx and warrants immediate thoracic decompression w/o x-ray confirmation of the dx
do isolated intracranial injuries cause shock
NO
What is the classic picture of neurogenic shock
hypotension w/o tachycardia or cutaneous vasoconstriction
a narrowed pulse pressure is not seen in neurogenic shock
how is the blood volume calculated in an adult and pediatric patient
adult - 7% of body weight
obese - 7% of IDEAL body weight
child - 8 - 9% of body weight
characteristics of class I hemorrhage
its exemplified by the condition of an individual who has donated a unit of blood
blood loss: ≤750ml, ≤15% HR: <100 resp. rate: 14 -20 urine output: >30ml/hr CNS/mental status: slightly anxious initial fluid replacement: crystalloid
characteristics of class II hemorrhage
in uncomplicated hemorrhage for which crystalloid fluid resuscitation is required
blood loss: 750 - 1500 ml, 15 - 30% HR: 100 - 120 resp. rate: 20 - 30 urine output: 20 - 30ml/hr CNS/mental status: mildly anxious initial fluid replacement: crystalloid
characteristics of class III hemorrhage
is a complicated hemorrhagic state in which at least crystalloid infusion is required and perhaps also blood replacement
blood loss: 1500 - 2000 ml, 30 - 40% HR: 120 - 140 BP: decreased resp. rate: 30 - 40 urine output: 5 - 15ml/hr CNS/mental status: anxious, confused initial fluid replacement: crystalloid and blood
characteristics of class IV hemorrhage
is considered a terminal event; unless very aggressive measures are taken, the pt will die within minutes
blood loss: >2000, >40% HR: >140 BP: decreased resp. rate: >35 urine output: negligible CNS/mental status: confused, lethargic initial fluid replacement: crystalloid and blood
what is the basic management principle in the initial management of hemorrhagic shock
stop the bleeding
replace volume loss
what are the solutions used for initial resuscitation
Warmed isotonic electrolyte solutions
- Lactated Ringer’s
- normal saline
this type of fluid provides transient intravascular expansion and further stabilizes the vascular volume by replacing accompanying fluid losses into the interstitial and intracellular spaced
an initial, warmed fluid bolus is given. The usual dose is 1 - 2 L for adults and 20mL for pediatric patients
cuales son las manifestaciones hemodinamicas mas frecuentes en choque distributivo
resistencias vasculares sitemicas bajas
gasto cardiaco elevado
presion venosa central baja
la variedad mas comun es el choque septico
caracteristicas del choque distributivo
taquicardia e hipotension que NO responde despues de admin. liquidos o vasopresores
caracteristicas del choque cardiogenico
el dx se establece despues de documentar disfuncion miocardica y excluir causas alternativas de hipotension (hipovolemia, hemorragia, sepsis, embolismo…)
cual es la causa mas frecuente del choque cardiogenico
infarto agudo al miocardio
cuales son las tres variantes clinicas que se puede presentar un un pt con choque cardiogenico
- normotenso/congestivo
- hipotenso/congestivo
- hipotension sin congestio
cuales son las manifestaciones de bajo gasto
palidez oliguria (diuresis <20ml/h) llenado capilar prolongado reacicon adrenergica: - piloereccion - tegumentos frios - diaforesis - cianosis periferica
caracteristicas del choque neurogenico
la variedad mas comun: traumatismo medular
existe una falta de vaso-regulacion sistemica
dependiendo del nivel de lesion medular, pueden presentarse hemiplejia superior con incapacidad para movilizacion de las extremidades, falta de sensibilidad en las mismas, y en muchas ocasiones insuf. respiratorioa
si existe daño medular bajo, se obervara hemiplejia inferior con falta de sensibilidad en las etremidade e incontinencia de esfinteres
c
cual es la dosis inicial de dobutamina en presencia de choque cardiogenico
dobutamina 5 - 10 microgramos/kg/min (como inotropico de inicio)
cual es el vasopresor de primera linea cuando se sospecha disminucion de las resistencias vasculares concurrente con gasto cardiaco alto
dopamina
luego sigue: norepinefrina o epinefrina
luego sigue vasopresina
