Gastrointestinal Flashcards
1
Q
FLUID THERAPY
A
-
%Water (balances @ approx 1y)
- Preemies ~90%
- NB ~70-80%
- Adult ~60%
- ECF>ICF before 6 months
- ICF>ECF after 6 months
- ICF– 30-40%, fluid within cells, K+, Phos-
- ECF– 20-25%, fluid surrounding cells (extravascular, intravascular), Na+, Bicarb
2
Q
Maintenance fluid
A
Wt mL/day Est mL/hr
<10kg – 100mL/kg – 4mL/kg
10-20 – 1000mL + 50mL/kg over 10kg
>20 – 1500mL + 20mL/kg over 20kg
3
Q
Maintenance Fluids Constituents
A
Water & Glucose (D5W to D20W)
- Provides 20% of normal caloric needs
- Dextrose adds osmoles to fluid
- Infants have a higher glucose need
- Higher BMR (100calories/kg baseline)
- Calories needed for growth & basal metabolism
- Low glycogen stores
- With stress, hypoglycemia results quickly
- Electrolytes – amount based on needs
- Na+ - required in nearly all fluids
- K, etc. - based on needs
- Always verify adequate UOP before adding K
4
Q
Maintenance Fluids Tonicity: Isotonic
A
Isotonic Fluids
- Osmolality of fluids equal to plasma osmolality
- 275-295 mOsm/L
- Ideal to keep electrolytes & fluid balanced
- Ex: NS, LR, D51/4NS, D51/2NS, D51/2NS + 20K
- Resus: NS, LR
5
Q
Hypotonic Fluids
A
- Infusing fluids with more water (relative to solute) than present in vessel & inside the cells
- Water shifts out of blood vessels into cells>cells swell & burst
- CV collapse from intravascular fluid depletion
- Increased ICP from fluid shift into the brain cells
- Red blood cells fill with fluid & rupture = hemolysis
- Inflammation, phlebitis, and infiltration at IV site
- Assess for signs of infiltration
- Ex: 1/2NS, 1/4NS, D5W
6
Q
Hypertonic Fluids
A
- 3% NaCl
- Indications:
- Severe hyponatremia with risk of seizures (120-125, 50% sz risk)
- Increased ICP
- CVL required
7
Q
Sodium
A
- Most abundant electrolyte in ECF
- Promotes neuromuscular function
- Maintains acid-base balance
- Influence kidney’s regulation of body water & electrolyte status (K+ & Cl- levels)
- When Na+ falls, kidneys promote diuresis
- When Na+ increases, kidneys retain water
- Maintenance depends on thirst mechanism & kidneys
8
Q
Potassium
A
Managing HyperK
- Correct underlying issue
- Calcium to alter cardiac effects – stabilize heart
Drive serum K+ back into the cells
- IV insulin with glucose
- Albuterol neb
- Sodium bicarbonate
Remove excessive serum K+
- Sodium polystyrene sulfonate (Kayexalate PO/PR)
- Loop, thiazide diuretics
- Dialysis
- Patiromer (Veltassa®) - not currently approved for children
-
MoA: Increases fecal potassium excretion through binding of potassium in the lumen of GI tract
- AE: Hypomagnesemia
- Interactions: Binding to other medications in the GI tract, decreasing GI absorption
- AE: Hypomagnesemia
-
MoA: Increases fecal potassium excretion through binding of potassium in the lumen of GI tract
9
Q
Hypercalcemia
A
Hypercalcemia
Results from:
- Immobilization
- Medications
- Malignancy
- Renal failure
Signs & symptoms:
- Constipation, dehydration, dry mouth
- Muscle hypotonicity
Treatment - Decrease levels
- Treat underlying condition
- Fluid therapy to dilute serum level
10
Q
Hypocalcemia
A
Hypocalcemia
Results from:
- Acute pancreatitis
- Excessive infusion of citrated blood
- Malabsorption
- Cow’s milk given to newborns
- Vitamin D deficiency
- Infants at higher risk
- Stress increases growth hormone secretion increasing deposits of Ca2+ into bone
- Infants already have low stores
- Unable to keep up with the demand to deposit Ca2+ into bones
- CHARGE, DiGeorge syndrome need 2x Ca2+
Signs & symptoms:
- Tingling of fingers and toes
- Abdominal & muscle cramps
- Seizures
Treatment:
- PO or IV supplementation (CaCl, Ca gluconate IV push; Tums)
11
Q
Magnesium
A
- Helps regulate intracellular metabolism
- Activates enzymes
- Affects metabolism of proteins
- Affects electrolyte balance
12
Q
Hypermagnesemia
A
Results from:
- Renal failure
- Overuse of antacids/laxatives
- Adrenal insufficiency
Signs & Symptoms (correlate to levels):
- Lethargy
- EKG changes
- Respiratory depression
- Hypotension (*SE of giving Mg IV too fast)
Treatment
- Administration of Ca2+ to stabilize heart
- Hydration to enhance excretion
- Hemodialysis (severe)
13
Q
Hypomagnesemia
A
Results from:
- Decreased intake
- Decreased intestinal absorption
- Diuretic therapy (thiazides, loops waste all e-s)
- Gastric losses (severe diarrhea)
Signs & Symptoms
- AMS
- Seizures
- Muscle spasms
- EKG Changes, arrythmias (Torsades)
Treatment – IV or PO supplementation
14
Q
Chloride
A
- Imbalances seen as acid-base disturbances
- Metabolic Acidosis
- Loss of bicarbonate in diarrheal stools
- Metabolic Alkalosis
- Loss of acid from vomiting or excessive gastric suction
- Common with diuretic therapy
- Losses of Na+ Cl- & H2O w/o a proportional loss of HCO3-
15
Q
Histamine-2 Receptor Antagonists
A
- Ranitidine (Zantac)
- Famotidine (Pepcid)
- 10-15x potency over ranitidine
- Longer t1⁄2 = less frequent IV dosing
- Indication: GERD, mild esophagitis
-
MoA: Reduce acid secretion stimulated by histamine and gastrin
- Histamine released from ECL cells by gastrin or vagal stimulation is blocked from binding to the parietal cell H2 receptor (blocks histamine<>histamine receptor = less acid)
- Direct stimulation of the parietal cell by gastrin/Ach to secrete acid doesn’t work as well in the presence of H2-receptor blockade (blocks gastrin<>parietal cell)
-
PK: rapidly absorbed from the intestine
- Undergo first-pass hepatic metabolism resulting in a bioavailability of approximately 50%
- Hepatically/renally cleared (reduce dose in renal impairment)
- AE: HA, irritability, somnolence, thrombocytopenia, agranulocytosis; *tolerance* after 6wk, not overcome by dose increase
