Acid/Base Disorders Flashcards
acidity is determined by the ____ ion concentration
H+
degree of acidity is described by the ____
pH
dissociation of acid/base pairs is dependent on ____ and ____
- dissociation constant 2. relative concentration of acid/base in solution
normal pH
7.4 (7.35 - 7.45)
normal PaCO2
40 (35-45)
normal HCO3-
24 (22-26)
effect of increase PaCO2
increase in acid content (decrease pH)
effects of decreased PaCO2
decrease in acid content (increase pH)
effects of increased HCO3
increase in base content (increase pH)
effected of decreased HCO3
decrease in base content (decrease pH)
pH is determined by the ratio of what?
HCO3 and PaCO2
Key extracellular buffers
carbonic acid/bicarb plasma proteins hemoglobin phosphates
What part is under respiratory control?

CO2
What part is under kidney control?

H+ and HCO3-
How much volatile acids are produced daily and excreted as CO2?
12,000 - 15,000 mEq
How are volatile gases eliminated?
as CO2 in lungs
How are nonvolatile acids eliminated?
kidneys
How much non-volatile acids ae produced daily and excreted by kidneys?
1 mEq/kg/day
4,500 mEq bicarb delivered to nephron and must be reabsorbed
the pH of body fluids is determined by what (3)
- amount of acid produced
- buffering capacity
- acid excretion by lungs and kidneys
What can be altered in respiratory system to accommodate acute changes in pH?
respirtory rate
tidal volume
What can be altered in kidney system to adjust pH?
change in bicarb
New HCO3 through ammoniagenesis
Are the lungs or kidney more responsive to acute acid/base changes?
lungs!
t/f the body will try to normalize pH and will return to normal pH
False!
NEVER return to normal pH
**except chronic respiratory alkalosis
Which compensation is faster? respiratory or renal?
Respiratory! (hours)
renal (days)
what equation is used to measure respiratory compensation?
Winters formula
Is insulin resistance a consequence of acidemia or alkalemia?
acidemia
Is impaired cardiac contractility a consequence of acidemia or alkalemia?
acidemia
Is bradycardia and heart block a consequence of acidemia or alkalemia?
acidemia
Is increase pulmonary vascular resistance a consequence of acidemia or alkalemia?
acidemia
Is hyperkalemia a consequence of acidemia or alkalemia?
acidemia
Is increased protein degradation a consequence of acidemia or alkalemia?
acidemia
Is reduction in ventricular fib threshold a consequence of acidemia or alkalemia?
acidmeia
Is arteriolar vasoconstriction a consequence of acidemia or alkalemia?
alkalemia
Is reduced coronary blood flow a consequence of acidemia or alkalemia?
alkalemia
Is reduced cerebral blood flow a consequence of acidemia or alkalemia?
alkalemia
Is hypokalemia a consequence of acidemia or alkalemia?
alkalemia
Is hypomagnesemia a consequence of acidemia or alkalemia?
alkalemia
Is hypophosphatemia a consequence of acidemia or alkalemia?
alkalemia
Is hypocalcimia a consequence of acidemia or alkalemia?
alkalemia
Is seziures, lethargy, delirium a consequence of acidemia or alkalemia?
alkalemia
Where do you get an arterial blood gas sample?
Radial artery
Potential complications of getting arterial blood gas (ABG)
- site pain
- hematoma
- infection
- arterial occlusion or thrombosis
Potential limitations with collection and analysis of ABG
sample should be drawn, chilled and analyzed within 30 mins
Acidemic pH
<7.35
alkalemic pH
>7.45
PaCO2 of respiratory acidosis
>40
PaCO2 of respiratory alkalosis
<40
HCO3- of metabolic acidosis
<22
HCO3- of metabolic alkalosis
>26
What acromyn do you use for acute respiratoyr acidosis?
CAPPHN
Acute respiratory acidosis causes (acronym)
CNS depression
Airway obstruction
Pulmonary edema
Pneumonia
Hemo/pneumothorax
Neuromuscular
**anything causing hypoventilation
3 overall causes of acute respiratory acidosis
- inadequate minute ventilation
- increased dead space ventilation (COPD)
- increased carb metabolism (TPN)
Clinical presentation of acute respiratory acidosis
- altered mental status
- headache
- papilledema
- focal paresis
- seizures
- coma
treatment of acute respiratory acidosis
- restore ventilation
- oxygen
Do you give bicarb to acute respiratory acidosis?
not routinely necessay
may precipiate metabolic alkalosis or suppres patient ability to breath
What acronym do you use for acute respiratory alkalosis?
CHAMPS
CAPPHN - C
CNS depression
COPD
(acute resp acidosis)
CAPPHN - A
Airway obstruction
Apnea
ARDS
(acute resp acidosis)
CAPPHN - P x 2
pulmonary edema
pneumonia
(acute resp acidosis)
CAPPHN - H
hemo/pneumonthorax
Hypnotics/sedative
(acute resp acidosis)
CAPPHN - N
Neuromuscular (acute resp acidosis)
CHAMPS - C
CNS disease (acute resp alkalosis)
CHAMPS - H
hypocapnia
Hepatic encephalopathy
Hypoxia
(acute resp alkalosis)
CHAMPS - A
Anxiety
altitude sickness
(acute resp alkalosis)
CHAMPS - M
mechanical ventilation (acute resp alkalosis)
CHAMPS - P
progesterone/PE
pregnancy
(acute resp alkalosis)
CHAMPS - S
salicylate/sepsis (acute resp alkalosis)
Causes of acute respiratory alkalosis (acronym)
CNS disease
Hypocapnia
Anxiety
Mechanical ventilation
Progesterone/PE
Salicylate
treatment of respiratory alkalosis
treat underlying condition
- slow down breathing (analgesia, anxiolytics)
- correct hypoxemia
- if ventilated, make adjustments (TV or RR)
T/F with compensatory responses the body will return to normal pH
False! try to normalize pH, never return to normal
EXCEPT chronic resp alkalosis
Compensaory mechanisms are dependent on appropriately working _____ and _____
kidneys
lungs
Is respirator or renal compensation quicker?
respiratory (hours)
renal (days
3 main causes of chronic respiratory acidosis
- chronic lung disease
- chronic neuromuscular disease
- chronic respiratory center depression
Chronic lung disease causes of chronic respiratory acidosis
COPD
pulmonary fibrosis
interstitial pulmonary disease
chronic neuromuscular disease causes of chronic respiratory acidosis
Guillian Barre
ALS
Myasthenia Gravis
Management of chronic respiratory acidosis
- clear secretions
- relieve bronchospasm (bronchodilators, steroids)
- aggressively treat CHF or pulm infections
- avoid excessive O2 delivery
Do you use winters formula in respiratory or metabolic disorder?
metabolic
After winters equation, if measured PaCO2 is < than expected then what?
co-existing respiratory alkalosis
After winters equation, if measured PaCO2 is > than expected then what?
co-exisiting respiratory acidosis
A high anion gap means here is a loss of _____ and indicates _____
Bicarb
acidosis
When there is an ______ in acid, there is an increase in anion gap because _____ is decrease in response to _____ the excess acid
increase
bicarb
buffer
Acronym for increase anion gap
MUDPILERS
MUDPILERS - M
Methanol/metformin (increased AG)
MUDPILERS - U
uremia (increased AG)
MUDPILERS - D
DKA (increased AG)
MUDPILERS - P
Paraldehyde (incrased AG)
MUDPILERS - I
isoniazid/iron
(increased AG)
MUDPILERS - L
Lactic acid (increased AG)
MUDPILERS - E
ethylene glycol/ethanol (increased AG)
MUDPILERS - R
Renal failure (increased AG)
MUDPILERS - S
Salicylates (increased AG)
limitations of anion gap
hypoalbuminemia can affect observed AG
Measured AG and hypoalbuminemia
decrease 3 mmol for ever 1 g/dL decrease in albumin
acronym for non-anion gap
HARDUPS
HARDUPS - H
hyperalimentation
HCl admin
(non-AG)
HARDUPS - A
acetazolamide (non-AG)
HARDUPS - R
Renal tubular acidosis
renal bicarb loss
CAIs
(non-AG)
HARDUPS - D
diarrhea (non-AG)
HARDUPS - U
uretero-pelvic shunt
ureteral diversion
(non-AG)
HARDUPS - P
post-hypocapnia
HARDUPS - S
spironolactone (non-AG)
What is delta gap used for?
assist determination for mixed acid/base disorders
Delta gap + measured HCO3 = ____ or higher then what is occuring?
28
underlying concurrent metabolic alkalosis
delta gap + measured HCO3 < ____ then what is occuring?
20
underlying concurrent nongap metabolic acidosis
If there is an underlying nongap metabolic acidosis what could be the causes?
GI loss bicarb (diarrhea)
renal loss bicarb (RTA, ATN, hypoaldosterone)
dilutional (post resuscitation)
Metabolic acidosis treatment
- correct the cause
- renal loss: give bicarb (not in AG acidosis)
- control diarrhea
- DKA: fluids, insulin
- lactic acidosis: improve hemodynamics
- intoxication: treat
Would you use bicarb in metabolic acidosis?
Yes, but not in anion gap acidosis
acronym for metabolic alkalosis
CLEVERPD
CLEVERPD - C
contraction (metabolic alkalosis)
CLEVERPD - L
licorice (metabolic alkalosis)
CLEVERPD - E x 2
excess alkali
endocrine (Conn/cushing)
(metabolic alkalosis)
CLEVERPD - V
vomiting (metabolic alkalosis)
CLEVERPD - R
refeeding (metabolic alkalosis)
CLEVERPD - P
post-hypercapnia (metabolic alkalosis)
CLEVERPD - D
diuretics (metabolic alkalosis)
metabolic alkalosis causes (acronym)
Contraction
Licorice
Endocrine (conn/cushing)
Vomiting
Excess alkali
Refeeding
Post-hypercapnia
Diuretics
Non-anion gap causes (acronym)
Hyperalimentation/HCl admin
Acetazolamide
Renal bicarb loss/renal tubular acidosis
Diarrhea
Uretero-pelvic shunt/diversion
Post-hypocapnia
Spironolactone
Anion gap causes (acronym)
Methanol/metformin
Uremia
- *D**KA
- *P**araldehyde
Isoniazide/irone
Lactic acid
Ethylene glycol/ethanol
Renal failure
Salicylates
metabolic alkalosis treatment
treat underlying disease
- rehydrate with normal saline with K
- if excess mineralocorticoid acvitiy: aldosterone inhibition (spironolactone, amiloride, triamterene)