Exam 3- Pales- acid base Flashcards
what is hyperkapnia or hypokapnia
increased or decreased CO2 in blood
what is minute ventilation
rate by which air reaches alveoli
what is the quickest compensation mechanism of the body(minutes)
buffering
how long does metabolic compensation take in kidneys
2-3 days
What can cause respiratory acidosis
decreased RR or decreased Tidal Volume
what are the causes of decreased RR
decreased drive: drugs, coma stroke
what are causes of decreased tidal volume
neuro-muscular disorders severe kyphoscholiosis ariway obstruction COPD obstructive sleep apnea/obesity
What are the types of metabolic acidosis
normal anion gap and high anion gap
what does anion gap actually mean
unmeasured anions in plasma: albumin, phosphate, sulfate, organic anions
What are causes of high anion gap metabolic acidosis
methanol, uremia, diabetic ketoacidosis, paraldehyde, infection, iron, isoniazide, lactic acidosis, ethylene glycol, alcohol, salicylates, starvation ketoacidosis
what is uremic acidosis
severe renal fucntion
Creatinine is less than 25
what causes uremic acidosis
decreased excretion of acids, J and decreased reabsorption of HCO3
what are causes of lactic acidosis
anaerobic metabolis: hypozemia, circulatory failure, peripheral vessel blockage, anemia
medications: metformin, some HIV meds and isoniazide
liver failure, thiamine deficiency, hypophosphatemia
sepsis and seizures
how do you Dx lactic acidosis
measuring venous or arterial
What causes diabetic ketoacidosis
insulin deficiency increases lypolysis which increase FFA to liver and increase ketone production leading to acidosis
how does alcohol lead to ketoacidosis
altered hormonal and enzymatic activities leading to ketone production
what is difference of diabetic ketoacidosis with alcoholic?
no hyperglycemia in alcoholic ketoacidosis
what is a normal osmol gap
<10
what is calculated osmolality
2 Na+ glucose/18 +BUN/2.8
how do you know if acidosis caused by ethanol
ethanol level/4.6 should be equal to the osmol gap
what are signs of ethylene glycol poisoning
metabolites hgihly toxic
increased osmol gap
Ca oxalate crystals in urine
ARF common
what are signs of methanol poisoning
found in wood alcohol and windshield fluid, causes blindess and ARF
increased osmol gap
what are symptoms of salicylates poisoning
hemorrhage, fever, nausea, vomiting, diaphoresis, tinnitus, pulmonary edema
what are causes of normal anion gap metabolic acidosis
diarrhea, ileal drainage with stoma/bypasses
decrease reabsorption of HCO3 by renal tubules
Increase anion intakes
large amount to NaCl
how does diarrhea lead to metabolic acidosis
loss of HCO3
unless chloride wasting diarrhea with villous adenoma
what can cause a decrease in reabsorption of HCO3 by renal tubules
RTA
CA inhibitors
what can lead to a large amount of NaCl in normal anion gap metabolic acidosis
“expansion acidosis” dilution of bicarb
decreased bicarb reabsorption from volume expansion
describe RTA type I
distal. decreased H excretion in collecting ducts
increased Ca excretion and decreased citric acid concentration leading to kidney stone formation
increased potassium loss
describe RTA II
defect in HCO3 reabsorption in proximal tubules
increased Ca in urine, but normal citric acid concentration
distal tubules ok so try to compensate urine pH( will not see a big difference from normal)
hypokalemia
describe RTA IV
distal hyperkalemic
in patients with moderate chronic renal failure
insufficient aldosterone production or aldosterone tubular resistance
insufficient K excretion leads to hyperkalemia
What is the pH in all types RTA
type I >5.5
type II <5.5
what are serum K levels in types of RTA
I low
II low
III high
kidney stones are assoc with which type RTA
I, distal
how do you differentiate between RTA and diarrhea as cause of HCO3 loss
urine anion gap
if negative (more cations than anions) extrarenal loss
high level NH4
if positive (more anions than cations) renal loss
low level NH4
What are causes of respiratory alkalosis
pain, anxiety, salicylates overdose, fever, sepsis, hypoxia (CHF, pneumonia, PE), mild asthma, mechanical ventilation
what are causes of metabolic alkalosis
vomiting/NG suction
contraction alkalosis from increased HCO3 reabsorption
hypokalemia
recent correction chronic resp acidosis
what are types of contraction alkalosis(increased HCO3) leading to metabolic alkalosis
dehydration, diuresis
increased mineralocorticoid secretion can lead to what imbalance with potassium and what broad metabolic acid base disorder
hypokalemia causing metabolic alkalosis
What are manifestations of metabolic acidoss
kussmaul respiration
nausea/vomiting, cardiac effects (arrhythmia and hypotension) neuro (confusion, lethargy, coma
what are manifestations of respiratory acidosis
ineffective respiration/respiratory distress
cardiac effects: arrhythmia hypotension
neuro: confusion, lethargy coma(hypercapnic, CO2 narcosis)
what are manifestations of metabolic alkalosis
decreased respiration
neuro: paresthesia, carpopedal spasm, confusion, seizures, dizziness, coma
weakness
what are manifestations of respiratory alkalosis
hyperventilation, deep (not kussmaul)
neuro:paresthesia, dizziness
symptoms of underlying disease
What are the 7 steps for reading ABG
1) look at pH above or below 7.4
2) look at HCO3 to determine if metabolic or respiratory (does it match pH)
3) determine if compensated or uncompensated, or partially
4) calculate anion cap to see if meatbolic acidosis
5) if have anion gap, calculate delta delta gap for mixed disorders
6) if metabolic look at pCO2 to determine if additional respiratory process exist
7) look at clinical picture
How do you calculate anion gap when patient has extremley high glucose
add 1 Na for every 100 mg/dl glucose
how do you calculate delta anion gap
(AG-10) / (24-HCO3)
if 1-1.6 only metabolic acidosis
if less than 1 concomitant non AG acidosis
>1.6 concomitant metabolic alkalsosis
describe telling if additonal resp problem if a metabolic problem exists
see if pCO2 goes in same direction as pH
if same, no resp
if opp directions then additional respiratory
what is step 1 ABG
alkalosis vs acidosis
what is step 2 ABG
metabolic or respiratory? look at HCO3 and see if match pH
what are the midline numbers for ABG
pH 7.4
pCO2 40
HCO3 24
what is step 3 ABG
determine if compensated or uncompensated. Look at pH with metabolic!
What is step 4 ABG
anion gap
what is step 5 ABG
delta anion gap
AG-10)/(24-HCO3
what is step 6 ABG
if metabolic look at pCO2 to see if goes along or not with HCO3. if so no other resp disorder
if against, another disorder
skip if primary is respiratory
what is normal AG
10
what are delta gap interpretations
if 1-1.6 pure high AG metabolic acidosis(no other)
if less than 1, concomitant non-AG acidosis
If more than 1.6 concomitant metabolic alkalosis
If case is respiratory how do you calculate step 3 ABG–> compensation?
for each 10 mmHg increase pCO2 there is increase in HCO3
if HCO3 inc 1 mmole- no compensation
3-5 mmol– compensation
for each 10 mmHg decrease in pCO2 there is a dec in HCO3
1-1 mmol– no compensation
5 mmol compensation
