abfecp - ProfJameson
Download
Report
Transcript abfecp - ProfJameson
PreWork
This powerpoint
will only be helpful
if you run it as a
slide show.
PreWork Objectives
Understand the respiratory and metabolic
mechanism for eliminating acid
Know the normals for Arterial Blood Gasses
and Venous Electrolytes
Explain ADH and Aldosterone effects on
sodium and water.
Explain the effects of sodium and free water
on volume and serum sodium
Explain hormonal regulation of Ca++ and P04
Problem: Metabolism
Produces Acid
H2SO4
H3PO4
HCl
etc.
Getting Rid of Acid
Bicarbonate Reabsorption by the
Kidneys (Metabolic)
Blood
Carbonic Anhydrase
HCO3-
H2CO3
Urine
H+
Getting Rid of Acid
The Lungs Eliminate CO2
(Respiratory)
HCO3-
+ H+
Acidic
H2CO3
Carbonic Acid
H2O + CO2
Getting Rid of Acid
The Lungs Eliminate CO2
(Respiratory)
HCO3Acid
+ H+
H2CO3
H2O + CO2
Carbonic Acid
pH
Alveoli
Normals
Arterial
Blood
pH:
7.35-7.45
pCO2: 40
PO2: 100
HCO3 25
Normals
Venous
Lytes
Sodium:
140
Potassium: 4.5
Chloride
100
Total CO2
26
Total CO2
pCO2 =40mm Hg
Dissolved
in/ L
Water
…..
40mm
1.2
HgmEq
EQUALS
dissolved
+
CO2
25 mEq /L of HCO3
=26
mEq / L = Total CO2
Click Here to Play That Again if
you didn’t get it
Sodium and Water Prework
Volume and Tonicity
Salt rules volume
Salt
Rules
Volume
This represents normal sodium
and volume. Extracellular
space is the vascular plus tissue
Note that intracelluar
space is 2/3 of total
body water
Intracellular
Serum
Sodium
140 mEq/L
(Unchanged)
Serum
Sodium
140 mEq/L
Extracellular
Intracellular
Free Water Rules Serum
Sodium
This represents normal sodium
and volume. Extracellular
space is the vascular plus tissue
Note that intracelluar
space is 2/3 of total
body water
Intracellular
Serum
Serum
Sodium
Sodium
125
mEq/L
140 mEq/L
(hyponatremia)
Extracellular
No Clinically
Significant Volume
Change
(Water Spreads Out)
Intracellular
The Challenge
Figure
out how the ReninAngiotensin-Aldosterone system
and how ADH relate to the above
examples of sodium and water.
What turns them on and what
turns them off.
Calcium And Phosphate Prework
Prework
questions on Calcium
and Phosphate will be easy.
Exam questions will be slightly
less easy.
Calcium
Calcium
Normal value:
Total: 8.5–10.5 mg/dL (2.1–2.7 mmol/L)
Ionized (free): 4.6–5.2 mg/dL (1.15–1.38 mmol/L)
Function
Bone and teeth
Neuromuscular activity (SA node, AV node)
Endocrine/exocrine function
Platelet function
Muscle cell contraction
Calcium Regulation
PTH
Vitamin D
serum calcium
Calcitonin
serum calcium
serum calcium
Calcium homeostasis figure (next
slide)
http://www.biol.andrews.edu/fb/spring/Chap.45-%20Endocrinology/4510.jpg
Corrected Calcium
Only ionized (unbound) calcium is active
Calcium must be corrected when there is a
low albumin (a larger percent is ionized)
For each 1mg/dl change in albumin from
normal, 0.8mg/dl change in Ca2+
[(4 – alb) x 0.8] + serum Ca2+
Ex. Alb 2.3 Ca2+ 7.6
Corrected calcium =
[(4-2.3) x 0.8] + 7.6 = 8.96 mg/dL
Hypocalcemia
Serum Ca2+ < 8.5 mg/dL
Pathophysiology
Hypoparathyroidism
Vitamin D deficiency
Hypomagnesemia
o
Hyperphosphatemia, 2 hypoparathyroidism
Medications/chelating agents
Bisphosphonates,
phenytoin
loop diuretics, calcitonin,
Hypocalcemia
Clinical
Presentation
Acute
Fatigue,
irritability, confusion, seizures
Muscle cramps, spasms, tetany
Chronic
Prolonged
QT interval
Brittle nails, hair loss
Hypocalcemia Treatment
Always correct calcium for albumin!!
Depends on acuity and severity
Check a magnesium level (find out
why for the exam! )
Calcium supplementation
IV
PO
IV Calcium
Acute symptomatic patients
Calcium chloride
1
gm IV (27% elemental)
Very irritating to veins
Calcium gluconate
2-3
gm IV (9% elemental)
availability in liver disease
PO Calcium
Chronic asymptomatic patients
Corrected symptomatic patients
1-3 g/day of elemental calcium ±
vitamin D
Take with meals,
in divided doses for
best absorption
PO Calcium
Calcium Salt
Carbonate
(Tums®,
OsCal®,
VIACTIV®)
Acetate
(PhosLo®)
used as a phosphate binder
Citrate
(Citracal®) Important: Use when
patient has little stomach acid (PPI)
Elemental
Calcium
40%
25%
21%
Hypocalcemia Monitoring
Albumin,
magnesium levels
Symptomatic patient
Serum
and ionized calcium levels
every 4-6 hrs after IV calcium
Serum calcium every 24-48 hrs
during oral therapy, then 1-2 times
weekly
Hypercalcemia
Ca2+ > 10.5 mg/dL
Pathophysiology
Serum
Primary
hyperparathyroidism**
Malignancy**
Other
High
bone turnover, sarcoidosis
Medications (thiazides, lithium, vitamin D)
Hypercalcemia
Clinical Presentation
Depends
on degree and onset
GI – N/V, anorexia, constipation
CV – short QT, prolonged PR & QRS
Neuro – fatigue, weakness, confusion
Renal – polyuria, nocturia,
nephrolithiasis
Hypercalcemia Treatment
Drug
Dose
Onset
0.9% NS (plus
200-300 cc/hr
furosemide below)
* First line therapy
24-48 hrs
Furosemide
40-80 mg IV q 1-4 hrs
Upon diuresis
Calcitonin
4 units/kg SC or IM q 12 hrs
1-2 hrs
Bisphosphonates
Pamidronate 30-90 mg IV
over 2-24 hrs
1-2 days
Prednisone
40-60 mg/day
1-2 weeks
Hypercalcemia Treatment
Other treatment options
Gallium
nitrate, mithramycin
Monitoring
Albumin
ECG
Ca2+ q 6-12 hrs if symptomatic
Serum Ca2+ daily if mild-moderate
Serum
Summary of Calcium
Calcium
regulation
PTH,
Vitamin D, calcitonin
Corrected calcium
Oral
calcium products
Treatment of hypercalcemia
Phosphorus
Phosphorus
Normal
value 2.7-4.5 mg/dL
Function
Phospholipid
membrane
Supports bone and teeth
Metabolism of nutrients
Source of ATP (energy, kinda critical)
Phosphorus
Source
Meats,
dairy, eggs
Regulation
Kidney
Hypophosphatemia
Mild to Moderate 1-2 mg/dL
Severe < 1 mg/dL
Pathophysiology
Decreased
Vitamin
intake/absorption
D deficiency, phosphate binders
Increased
Diuretics,
excretion
hyperparathyroidism
Intracellular
Parenteral
shift
nutrition, insulin
Hypophosphatemia
Clinical
Presentation
– irritability, weakness,
seizures
Muscular – myalgia
Hematologic – hemolysis
Pulmonary – respiratory distress
Other – osteomalacia, arrhythmias
Neuro
Hypophosphatemia Tx
Mild
– moderate
PO
50-60
mmol/day divided in 3-4 doses
Neutra-Phos 1-2 packets QID mixed in 2.5 oz
water or juice
o K-Phos Neutral 1-2 tabs QID with water
o
NOTE:
Dose in mmol NOT mEq
Hypophosphatemia Tx
Mild
– moderate
IV
0.08-0.15
mmol/kg IV
Repeat until serum phosphorus > 2 mg/dL
Hypophosphatemia Tx
Severe
IV
0.25-0.5
mmol/kg IV
Repeat until serum phosphorus > 2 mg/dL
Phosphorus Replacement
Product
Phos Content
Na Content
K Content
K-Phos Neutral* 250mg 8 mmol
13 mEq
1.1 mEq
Fleet Phospho-soda*
20 mmol
24 mEq
0
Sodium Phosphate
3 mmol/mL
4 mEq/mL
0
K-Phos Original
Dissolving Tablets
3.6
0
3.7mEq
Neutra-Phos* 250mg
Recently
discontinued
Doesn’t
matter!
Neutra-Phos K* 250mg
Recently
discontinued
Doesn’t
matter!
Typically used as laxative
*Oral agents
Hypophosphatemia
Monitoring
IV
therapy
Serum
PO
phosphorus every 6 hrs
therapy
Serum
Renal
phosphorus daily
function, BP (IV)
Adverse events – diarrhea (PO), soft
tissue calcification, hypocalcemia,
hypotension (IV)
Hyperphosphatemia
Serum phos > 4.5 mg/dL
Pathophysiology
Decreased
Renal
urinary excretion
failure, hypoparathyroidism
Increased
intake
Parenteral
nutrition, phosphate enemas
Extracellular
Acidosis
shift
Hyperphosphatemia
Clinical
Presentation
N/V,
muscle pain/weakness,
hyperreflexia, tetany
Soft Tissue calcification
Due
to calcium-phosphate product
Goal is less than 55.
Hyperphosphatemia Tx
Restrict dairy products
Phosphate binders
Aluminum
and magnesium-based
antacids
No
longer first line, avoid in renal failure
Calcium
(Drug of first choice unless
Calcium is high)
Sevelamer
Binding
resin Usually given with meals
Hyperphosphatemia
Monitoring
Serum
calcium level
Serum phosphorus level daily
Renal function
Summary of Phosphorus
IV
vs. PO replacement
Give
IV phosphorus when severe
hypophosphatemia
Medications
affecting serum
levels
Phosphate-binders,
calcium,
diuretics, insulin, vitamin D