Hypovolemia and Dehydration PDF

Shock  Syndrome characterized by decreased tissue perfusion and impaired cellular metabolism  Imbalance in supply/demand for O2 and nutrients Shock  Classification of shock  Low blood flow  Cardiogenic  Hypovolemic  Maldistribution of blood flow  Septic  An...

Shock  Syndrome characterized by decreased tissue perfusion and impaired cellular metabolism  Imbalance in supply/demand for O2 and nutrients Shock  Classification of shock  Low blood flow  Cardiogenic  Hypovolemic  Maldistribution of blood flow  Septic  Anaphylactic  Neurogenic S Septic, Spinal H Hypovolemic O Obstructive, Mechanical C Cardiogenic K Anaphylactic Low Blood Flow Hypovolemic Shock  Absolute hypovolemia: Loss of intravascular fluid volume  Hemorrhage  GI loss (e.g., vomiting, diarrhea)  Fistula drainage  Diabetes insipidus  Hyperglycemia  Diuresis  Relative hypovolemia  Results when fluid volume moves out of the vascular space into extravascular space (e.g., interstitial or intracavitary space)  Termed third spacing Another classification ◆ Hemorrhagic ◆ Internal blood loss, eg. G.I bleed ◆ External blood loss, laceration ◆ Non-Hemorrhagic ◆ G.I losses prolonged severe vomiting and diarrhea ◆ Renal losses excessive use of diuretics. Pathophysiology of Hypovolemic Shock Copyright © 2010, 2007, 2004, 2000, Mosby, Inc., an affiliate of Elsevier Inc. All Rights Reserved. Low Blood Flow Hypovolemic Shock  Clinical manifestations  Anxiety  Tachypnea  Increase heart rate  Hypotension  If loss is >30%, blood volume is replaced Stages of Shock 1st Stage: 0-15 % of blood volume 2nd Stage: 15-30% of blood volume 3rd Stage: 30-40% of blood volume 4th Stage: >40% Refractory Stage (Irreversible)  Exacerbation of anaerobic metabolism  Accumulation of lactic acid  ↑ Capillary permeability  Profound hypotension and hypoxemia  Tachycardia worsens  Decreased coronary blood flow  Cerebral ischemia  Failure of one organ system affects others  Recovery unlikely Management ABCs: Airway, breathing, and circulation Focused assessment of tissue perfusion Vital signs Peripheral pulses Level of consciousness Urine output & CVP  Cornerstone of therapy for septic, hypovolemic, and anaphylactic shock = volume expansion  Isotonic crystalloids (e.g., normal saline) for initial resuscitation of shock Management focuses on stopping the loss of fluid and restoring the circulating volume  Fluid replacement is calculated using a 3:1 rule (3 ml of isotonic crystalloid for every 1 ml of estimated blood loss)   Volume expansion  If the patient does not respond to 2 to 3 L of crystalloids, blood administration and central venous monitoring may be instituted  Complications of fluid resuscitation  Hypothermia  Coagulopathy  Primary goal of drug therapy = correction of decreased tissue perfusion  Vasopressor drugs (e.g., epinephrine)  Achieve/maintain MAP >60 to 65 mm Hg  Reserved for patients unresponsive to other therapies