Resuscitative principles:
ABC and monitoring
IV access: Large bore, central lines, rapid infusers.
Fluid resuscitation: IVF crystalloids and colloids. Based on clinical parameters: ABP, UO, cardiac filling pressures, CO, mental status if not sedated or intubated.
Crystalloids (NS or RL). Aggressive fluid resuscitation in hypovolemic shock in the absence of signs of CHF.
Colloids (albumin 5% - 25%; hetastarch 6%, dextran 40 and dextran 70). Blood products if patient has anemia or active H'ge.
Young adequately resuscitated patients should usually tolerate Hcts of 20% - 25%.
Older patients with CVS comorbidities may need Hct to be maintained >30%, to optimize O2 to tissues.
Vasopressors and inotropes: Important role. Need monitoring with ABP and PA cath (Swan-Ganz). Make sure patient is in fluid resuscitation.
Dopamine: Stimulates cardiac B1-rcp, peripheral alpha-rcp, and dopaminergic rcp in renal, splanchnic, and other vascular beds.
< 5 mcg/kg/min, renal and splanchnic vasodilatory. Increases UO transiently. No renal benefits. Makes UO number look better temporarily.
5 - 10 mcg/kg/min: ▲ CO, by activation of cardiac B1-rcp
>10 mcg/kg/min: ▲ BP, by activation of peripheral alpha-rcp.
Dobutamine: B1 agonist. Inotropic, reduces afterload by peripheral vasodilation, weak chrontropic (so does not send the heart racing). Good hemdynamic response: ▲ SV with modest increase in HR, unless used in high doses in hypovolemia.
Epinephrine: alpha1 and non-selective beta adrenergic activity. Agent of choice in anaphylactic shock. Dose dependent effects.
Norepinephrine: alpha1 and beta1-adrenergic activity. Primarily a potent vasoconstrictor.
Vasopressin: vasconstrictor mediated by 3 different G-peptide rcps, called V1a, V1b, and V2. Dose: 0.01 - 0.04 U/min
Milrinone is a noncatecholamine inhibitor of PDE III that acts as an inotrope and a direct peripheral vasodilator to increase CO.
Circulatory Shock: A process in which blood flow and oxygen delivery to tissues is impaired, resulting in inadequate tissue perfusion, and failure to meet cellular metabolic demands.
SBP <90, MAP <60, hypoperfusion (MS changes, oliguria 0.5 ml/kg/hr; skin mottling), lactic acidosis.
Shock if fluids, and 2 pressors used.
Classification:
Hypovolemic
Causes: Hypovolemic: trauma, GIB, ruptured Aorta, ruptured ectopic preg, burns, NH Pt. on diuretics.
Stages of Hypovolemic Shock:
Stage 1
Up to 15% blood volume loss (750 mL)
Compensated by constriction of vascular bed
Blood pressure maintained
Normal respiratory rate
Pallor of the skin
Slight anxiety
Tachycardia
Stage 2
15 - 30% blood volume loss (750 - 1500 mL)
Cardiac output cannot be maintained by arterial constriction
Tachycardia
Increased respiratory rate
Blood pressure maintained
Increased diastolic pressure
Narrow pulse pressure
Orthostatic changes
Sweating from sympathetic stimulation
Mildly anxious/Restless
Stage 3
30 - 40% blood volume loss (1500 - 2000 mL)
Systolic BP falls to 100 mm Hg or less
Classic signs of hypovolemic shock
Marked tachycardia > 120/min
Marked tachypnea > 30/min
Decreased systolic pressure
Alteration in mental status
Diaphoresis and pallor of skin
Stage 4
Loss greater than 40% (>2000 mL)
Extreme tachycardia with weak pulse
Pronounced tachypnea
SBP 70 mmHg or less
Decreased level of consciousness
Skin is sweaty, cool, and extremely pale (moribund)
Cardiogenic
MI, RV infarct, RV failure due to massive PE, septal wall rupture, acute MR, cardiac tamponade, CHF, DCM, arhythmias.
AMI results in ~40% loss of viable myocardium. STEMI causes shock.
Papillary muscle ruptured VSD - free wall rupture
RV infarct: results in hypotension, JVD, no pulmonary edema. R. sided ECG.
VSD ( has thrill). Check TTE
Drug related: BB, CCB OD; Adriamycin, severe AS, MS; severe tachycardia (AF with RVR); bradyarrhythmia (3° HB)
SBP <60, CI: <2, PAOP >18, altered mentation, ▼ UO = MI
Obstructive.
AS, coarctation of aortia, PE, PTx, air-embolism, tumor embolism. tamponade.
Tx cardiac tamponade medically with IVF bolus. Pericardiocentesis.
Distributive
Septic, neurogenic, and anaphylactic
Sepsis: when there is evidence of inf + SIRS
Severe sepsis: organ dysfunction and hypoperfusion.
Septic shock: sepsis with hypotension despite adequate fluid resuscitation 40 - 60 mL/kg, or need of pressors; combined with altered mental status, oliguria, and/or lactic acidosis.
Neurogenic
Loss of sympathetic tone resulting in hypotension
Anaphylactic
urticaria, angioedema, hypotension.
IV contrast - anaphylactoid shock, cause iodine is not an antigen.
Tx; with epi and steroids
Do not used Dobutamine if MAP <60. Add NE to raise MAP >60.
Isoproterenol used in severe bradyarrhythmia if no PPM available.
Phenylephrine used if shock with tachyarrhythmia with vasopressors.
Refractory shock: dopamine, >15 mcg/kg/min or NE: >0.25 mg/kg/min
Phenylephrine 0.5 mcg/kg 5 mcg/kg/min. Causes reflex bradycardia, alpha adrenergic
Dobutamine is not a pressor, but an Inotrope used in cardiogenic shock and sepsis. 2/5 mcg/kg/min
Cardiogenic shock:
PaO2 >60 mm Hg, Hct >30% or more. ETT and mech vent. BiPAP if Pt. spont. breathing. Fluid management carefully - adequate preload to optimize ventricular fx, esp. if RV infarct and avoid fluid overload in CHF > pulm. edema.
Inotropes and vasopressors. No vasodilators to start with. Consider later after cardiogenic shock resolved, to opitmize LV fx.
Dopamine dose titrated to maintain MAP of 60 mm Hg or greater. Use PA cath readings as a guide to check what else is needed, including other inotropes like dopamine, milrinone, or afterload reduction nitroprusside, and if changes in IVV needed in the form of IVF vs diuresis.
Mechanical circulatory assist devices: IAPB, LVAD
Angioplasty, CABG, Valve replacement, cardiac transplant
Obstructive shock usually 2° massive PE, air-embolism, tumor embolism.
IVF, vasoconstrictors (NE, dopamine), thrombolytic therapy or surgical embolectomy.
Distributive shock: septic or anaphylactic
Septic shock: IVF resuscitation, treat underlying infection, interrupt SIRS and sepsis.
Goal: SBP > 90 mm Hg, MAP > 60 mm Hg, CVP > 8 mm Hg, ScvO2 > 70% or above.
IVF initial bolus 20 mL/kg crystalloid. Targert CVP 8 - 12 cm H2.0
EGDT should be completed <6 hr. If ScV02 <70%
Levophed > vasporessin > dobuatamin
Glucose 140-150 mg/dL. Use insulin drip
RASS score 0 to -2
For hypothermia, -4 (deep sedation)
TOF 4 thumb twitches not enough; 2 twitches O.K, no twitches over medicated with paralytics - back off.