Outline Chapter 14 — Treatment

- Treatment

- Both oral and IV treatment can be used for volume replacement

- The goal of therapy are to restore normovolemia

- And to correct associated acid-base and electrolyte disorders

- Oral Therapy

- Usually can be accomplished with increased water and dietary sodium

- May use salt tablets

- Glucose often added to resuscitation fluids

- Provides calories

- Promotes intestinal Na reabsorption since there is coupled Na and Glucose similar to that seen in the proximal tubule

- Rice based solutions provide more calories and amino acids which also promote sodium reabsorption

- 80g/L of glucose with rice vs 20 g/L with glucose alone

- IV therapy

- Dextrose solutions

- Physiologically equivalent to water

- For correcting hypernatremia

- For covering insensible losses

- Watch for hyperglycemia

- Footnote warns against giving sterile water

- Saline solutions

- Most hypovolemic patients have a water and a sodium deficit

- Isotonic saline has a Na concentration of 154, similar to that of plasma see page 000

- Half-isotonic saline is equivalent to 550 ml of isotonic saline and 500 of free water. Is that a typo?

- 3% is a liter of hypertonic saline and 359 extra mEq of Na

- Dextrose in saline solutions

- Give a small amount of calories, otherwise useless

- Alkalinizing solutions

- 7.5% NaHCO3 in 50 ml ampules 44 mEq of Na and 44 mEq of HCO3

- Treat metabolic acidosis or hyperkalemia

- Why 44 mEq and not 50?

- Do not give with calcium will form insoluble CaCO3

- Polyionic solutions

- Ringers contains physiologic K and Ca

- Lactated Ringers adds 28 mEq of lactate

- Spreads myth of LR in lactic acidosis

- Potassium chloride

- Available as 2 mEq/mL

- Do not give as a bolus as it can cause fatal hyperkalemia

- Plasma volume expanders

- Albumin, polygelastins, hetastarch are restricted to vascular space

- 25% albumin can pull fluid into the vascular space

- 25% albumin is an albumin concentration of 25 g/dL compare to physiologic 4 g/dL

- Says it pulls in several times its own volume

- 5% albumin is like giving plasma

- Blood

- Which fluid?

- Look at osmolality, give hypotonic fluids to people with high osmolality

- Must include all electrolytes

- Example of adding 77 mEw of K to 0.45 NS and making it isotonic

- DI can be replaced with dextrose solutions, pure water deficit

- Case 14-3

- Diarrhea with metabolic acidosis

- He chooses 0.25 NS with 44 mEq of NaCl and 44 NaHCO3

- Talks about blood and trauma

- Some studies advocate delaying saline until penetrating trauma is corrected APR about to. Keep BP low to prevent bleeding. Worry about diluting coagulation factors

- Only do this if the OR is quickly available

- Volume deficit

- Provides formula for water deficit and sodium deficit

- Do not work for isotonic losses

- Provides a table to adjust fluid loss based on changes in Hgb or HCTZ

- Says difficult to estimate it from lab findings and calculations

- Follow serial exams

- Serial urine Na

- Rate of replacement

- Goal is not to give fluid but to induce a positive balance

- Suggests 50-100 ml/hr over what is coming out of the body

- Urine

- Insensibles 30-50

- Diarrhea

- Tubes

- Hypovolemic shock

- Due to bleeding

- Sequesting in third space

- Why shock?

- Progressive volume depletion leads to

- Increased sympathetic NS

- Increased Ang 2

- Initially this maintains BP, cerebral and coronary circulation

- But this can decrease splanchnic, renal and mucocutaneous perfusion

- This leads to lactic acicosis

- This can result in intracellular contents moving into circulation or translocation of gut bacteria

- Early therapy to prevent irreversible shock

- In dogs need to treat with in 2 hours

- In humans may need more than 4 hours

- Irreversible shock associated with pooling of blood in capillaries

- Vasomotor paralysis

- Hyperpolarization of vascular smooth muscle as depletion of ATP allows K to flowing out from K channels opening. Ca flows out too leading to vasodilation

- Glyburide is an K-ATP channel inhibitor (?) caused increased vasoconstriction and BP

- Pluggin of capillaries by neutrophils

- Cerebral ischemia

- Increased NO generation

- Which Fluids?

- Think of what is lost and replace that.

- Bleeding think blood