abgs Flashcards
abg use
gives best representation of pH and PaCO2
used to assess acid=base status and determine adequacy of oxygenation and ventillation
vbg
PaCO2 higher
so pH change and PO2 not accurate
PaCO2 normal
35 - 45
resp parameter
HCO3- normal
24 - 29
metabolic parameter, reported as CO2 on chm panel, calculated in ABG
primary event
problem that initiates acid-base imbalance -> hyper/hypovent, v/d, etc
primary disorder
results from primary event -> resp acidosis, met alkalosis, etc
compensation mechanisms
phys process that adjusts pH back to normal, lungs v kidneys
lungs = H2CO3, respiratory, not prolonged compensation
kidneys = HCO3, metabolic
metabolic alkalosis
too much bicarb or not enough carbonic acid
primary = high HCO3, compensation = high CO2 to decrease pH
give H2 blockers, PPI to retain H
metabolic aklalosis: causes
causes: too much baking soda, prolonged v (stomach acid loss), NG suction, diuretics (esp loop), aklaseltzer -> hypoK bc K goes into cell and H comes out
metabolic aklalosis: cm
CNS over excitability, confusion, tremor, muscle cramp, paresthesias (tingling of fingers and toes), coma, n/v/d, resp dep -> hold in to CO2, cardiac cm
restlessness followed by lethargy, dysR (tachy), compensatory hypovent, confusion (decreased LOC, dizzy, irritable), hypoK
respiratory alkalosis
H2CO3 (carbonic acid) deficit in ecf
hypervent = primary event, blow off CO2, can also happen with ventilation
give rebreather
respiratory alkalosis: causes
hypervent, ventilation, increased metabolic demands (fever, sepsis), meds, acute anx, hypoxia, PE or lung disease, CNS lesions, vent settings
respiratory alkalosis: cm
CNS overexcitability
tachypnea (deep and rapid, hypervent), light headed, confusion, blurred vision, paresthesia, hyperactive reflexes, seizure, coma
tachy, decreased or normal BP, hypoK, lethargy and confusion, light headed, n/v
resp acidosis
acute or chronic
hypovent = primary event -> CO2 retained (H+)
acute = resp arrest, chronic = COPD or oversedation
H2CO3 excess in ecf (too much acid/H+)
ABG low pH, CO2 high, HCO3- normal in acute (no time for kidneys to compensate)
HCO3- high and pH normal in chronic bc kidneys have time to compensate
put on vent, dont really give sodium bicarb
resp acidosis: causes
cardiopulm arrest, head injury, narcotics/sedatives, anesthesia, pain and abd distention (cant take deep breath)
pulm distress = acute asthma, CPOD exacerbation, pna, resp failure, drug OD, atelectasis
airway obstruction, chest wall deformities, NM problems bc muscles not strong enough (ALS, guillain-barre)
resp acidosis: cm
CNS dep causing hypovent and dyspnea, resp distress, shallow resp, anesthesia, HA, restless, confusion, tachy, arrhythmias (hypoerK), decreased LOC, stupor, coma
decreased BP with vasodilation, drowsy, dizzy, disorientation, muscle weak, hyperreflexia
metabolic acidosis
HCO3 (bicarb) deficit in ecf, excess acids added or bicarb loss
rapid acting insulin, sodium bicarb
metabolic acidosis: causes
renal fail
fistulas - F+E loss
DM - type 1 - DKA
lactic acidosis - not enough O2
prolonged d - relative increase in acid d/t decreased HCO3
starvation - usually fat for E, ketosis
shock
cardiac arrest
metabolic acidosis: cm
CNS: lethargy, drowsy, confusion, tremor, muscle cramp, paresthesia
hypoT, hyperK, deep breathing (kussmal resp - DKA)
resp acidosis: w/o compensation
low pH
high CO2
normal HCO3
resp acidosis: full compensation
pH normal
high CO2
high HCO3
resp alkalosis: w/o compensation
high pH
low CO2
normal HCO3
resp alkalosis: full compensation
pH normal
low CO2
low HCO3
met acidosis: uncompensated
low pH
normal CO2
low HCO3
met acidosis: full compensation
pH normal
low CO2
low HCO3
met alkalosis: uncompensated
high pH
CO2 normal
high HCO3
met alkalosis: full compensation
pH normal
CO2 high
HCO3 high
uncompensated
pH abn
acid or base abn
partially compensated
pH abn
acid and base abn (bc compensation kicking in)
compensated
pH wnl -> neutralized but not corrected acid/base balance, acid or base components are abn but balanced, arrows in same direction
corrected
pH wnl, all acid/base parameters wnl
COPD never reach
