Hemodynamics and Hypovolemic Shock

� Normal Systemic Vascular Resistance (SVR)

o 800-1200 dynes/sec/cm5

� Cardiac Output

o CO=HR x SV
o Normal = 4-8 L/min

� Cardiac Index

o CI=CO/BSA
o Normal = 2.5-4 L/min/m2

� Body Surface Area (BSA)

o Sqrt[(cm x kg)/3600]

� Tachycardia

o > 90 bpm
o Decreased stroke volume

� Bradycardia

o <60 bpm
o Increased stroke volume

� Stroke Volume

o CO=HR x SV
o Normal = 50-100 ml

� Blood Pressure

o BP = SVR x CO
o Normal = < 140/90

� Mean Arterial Pressure (MAP)

o Marker of tissue perfustion
o Calculation most accurate at HR of 60 bpm
o Measured area under pressure waveform divided by duration of the cardiac cycle
o MAP = (2*DBP + SBP)/3
o Normal = 70-100 mHg
o Goal = > 65 mmHg to maintain adequate perfusion (var

� Decreased urine output

o < 0.5 ml/kg/hr

� Heart Rate

o Normal = 60=100 bpm

� Pulmonary Capillary Wedge Pressure

o Pressure distal to the pulmonary artery
Left atrial pressure (LAP)
LV Preload
PCWP=LAP=LEVDP
o Use for measuring in Cardiogenic shock
o Congestive heart failure
o Normal = 4-12 mmHg

� Distributive shock Hemodynamics

o HR: Up
o BP: Down
o CO: Up early due to hemodynamics but decreases later
o Preload (PCWP): Down
o Afterload (SVR): Down

� Cardiogenic shock Hemodynamics

o HR: Up
o BP: Up or Down
o CO: Down
o Preload (PCWP): Up
o Afterload (SVR): Up

� Hypovolemic shock Hemodynamics

o HR: Up
o BP: Down
o CO: Down
o Preload (PCWP): Down
o Afterload (SVR): Up

� Hypovolemic Shock Clinical Presentation

o SBP < 90 mmHg or more than 40 mmHg decrease in baseline
o HR > 90 bpm
o RR > 22 bpm
o Cold, clammy, mottled skin
o Confusiton, agitation, stupor, or coma
o Oliguria: Urine output < 0.5ml/kg/hr
o Metabolic Acidosis: Lactic acid > 4 mmol/l

� Goals of Hypovolemic Therapy

o Improve mental status to baseline
o MAP > 65 mmHg, prevent ischemia
o SaO2 >= 90%
o Urine output > 0.5/kg/hr
o Improve skin color, temperature, reduce mottling

� How much IV fluids typically administered?

o 20 ml/kg based on volume status and perfusion

� 5% Dextrose composition (D5W)

o Like giving water
o Hypotonic
o Osmolarity: 253 m0sm/L

� 0.9% NaCl composition

o Na: 154 mEq/L
o Cl: 154 mEq/L
o Isotonic
o Osmolarity: 308 mOsm/L

� 0.45% NaCl composition

o Na: 77 mEq/L
o Cl: 77 mEq/L
o Hypotonic
o Osmolarity: 154 mOsm/L

� Lactated Ringer's

o Na: 130 mEq/L
o Cl: 109 mEq/L
o K: 4 mEq/L
o Ca: 3 mEq/L
o Lactate: 28 mEq/L
o Isotonic
o Osmolarity: 273 mOsm/L

� Plasmalyte

o Na: 140 mEq/L
o Cl: 103 mEq/L
o K: 10 mEq/L
o Ca: 5 mEq/L
o Mg: 3 mEq/L
o Lactate: 8 mEq/L
o Isotonic
o Osmolarity: 312 mEq/L

� Use Packed red blood cells for patients with

o Profound blood loss or continued deterioration despite IV fluids
o pRBCs increase oxygen carrying capacity by increasing Hemoglobin

� Use Platelets for patients with

o Bleeding due to severe thrombocytopenia (platelet count < 10,000)
o Reverses anticoagulant agents

� Use Fresh-frozen plasma (FFP) for patients with

o Ongoing hemorrhage with PT/PTT > 1.5 x normal
o Other bleeding disorders

� Use Albumin 5% for patients with

o Needed volume expansion or intravascularly depleted patients

� Use Albumin 25% in patients with

o Restricted fluid and sodium intake

� Central Venous Pressure (CVP)

o Mean pressure in the right atrium and RVEDP
o Determined by venous return to the heart
o Marker of fluid status and adequacy of fluid resuscitation
o Normal: 2-6 mmHg
o Goal Fluid Resuscitation (sepsis): 8-12 mmHg, 12-15 mmHg for ventilated patients

Vasopressors

o NE, dopamine
o constrict BVs to prevent pooling, so blood (in the interstitial space) can return to the heart
o BE SURE PT. IS ADEQUATELY HYDRATED PRIOR TO ADMINISTERING VASOPRESSORS
- Give IV Fluids!!!!!

Norepinephrine (NE) [Levophed]

o Vasopressor
o Vesicant [toxin] - causes tissue necrosis (extravasation) if infiltrates
o Assess IV site frequently; V/S q 5min
o ?? Know when it is working; what will you see with adequate perfusion?? stronger pulses, HR improving, increased MAP, increa

Dopamine

o Vasopressor
o constricts BVs to prevent pooling of blood in 3rd space, so blood can return to the heart
o REMEMBER: ensure pt is adequately hydrated prior to admin with IV Fluids (crystalloids), best is L.R.
o Monitor V/S q 5min; titrate appropriately

Intropics

o Dobutamine
o Increases contractility; greater force of contraction

Coronary artery dilators

o Nitroprusside
o Dilates the coronary artery to improve oxygenation
o Increased risk for hypotension
o Monitor B/P q 15min

Medications for Hypovolemic Shock - or any type of shock

o Vasopressors [NE, dopamine] constricts BVs
o Intropics [dobutamine] increases contractility
o Coronary artery dilators [nitroprusside]