ABGs - patho 406 Flashcards by Stef Sis

purpose of ABGs

to assess acid base status and to determine adequacy of oxygenation & ventilation

How well did you know this?

Not at all

Perfectly

primary event

the problem that initiates the acid base imbalance
(ex: hypovent, hypervent, vomiting, diarrhea)

How well did you know this?

Not at all

Perfectly

primary disorder

what results from the primary event
(ex: resp acidosis, metabolic alkalosis)

How well did you know this?

Not at all

Perfectly

compensation mechanisms

physiologic processes that adjust the pH back to the normal range
(ex: lung problem -> kidney will comp)

How well did you know this?

Not at all

Perfectly

general causes of imbalance: metabolic

-HCO3 level changes secondary to metabolic alterations (kidneys)

How well did you know this?

Not at all

Perfectly

general causes of imbalance: respiratory

-H2CO3 level changes secondary to respiratory alterations (lungs)

How well did you know this?

Not at all

Perfectly

respiratory acidosis or alkalosis

increases or decrease in CO2
change in ventilation

How well did you know this?

Not at all

Perfectly

metabolic acidosis or alkalosis

changes in H+ or bicarb ions

How well did you know this?

Not at all

Perfectly

acid base mnemonic: ROME

R espiratory
O pposite
inc pH, dec PCO2 = alk; dec pH, inc PCO2 = acid

M etabolic
E qual
inc pH, inc HCO3 = alk; dec pH dec HCO3 = acid

How well did you know this?

Not at all

Perfectly

metabolic acidosis: what is it & what is our comp

dec HCO3, dec Ph
comp: lungs blow off CO2 to decrease levels (dec pCO2)

How well did you know this?

Not at all

Perfectly

respiratory alkalosis: what is it & what is our comp

dec CO2, inc pH
comp: kidneys get rid of bicard (HCO3) to decrease levels
(dec HCO3)

How well did you know this?

Not at all

Perfectly

respiratory acidosis: what is it & what is our comp

inc pCO2, dec pH
comp: kidneys hold on to bicard to increase levels
(inc HCO3)

How well did you know this?

Not at all

Perfectly

metabolic alkalosis: what is it & what is our comp

inc HCO3, inc pH
comp: lung hold on to CO2 to increase levels
(inc pCO2)

How well did you know this?

Not at all

Perfectly

metabolic alkalosis: ABG

too much bicard or not enough carbonic acid
pH > 7.48 (B)
PaCO2: 35-45 (N)
HCO3 >29 (B)

How well did you know this?

Not at all

Perfectly

metabolic alkalosis: clinical manifestations

CNS over excitability
confusion
tremors
muscle cramps
parethesias
coma
N/V/D
resp depression (to try to hold on to CO2)

How well did you know this?

Not at all

Perfectly

respiratory alkalosis: ABGs

H2CO3 deficit in extracellular fluid
pH >7.45 (H/basic)
PaCO2 <35 (L)
HCO3-: 24-29 (N)

How well did you know this?

Not at all

Perfectly

respiratory alkalosis: causes

-hyperventilation (primary event)
kidneys need to comp but can’t work quickly so often time these pts pass out
-fever / sepsis (inc metabolic demand)
-medications
-acute anxiety
-hypoxia
-PE or lung disease
-CNS lesions
-ventilator

respiratory alkalosis: clinical manifestations

-CNS over excitability
-tachypnea
-light headedness
-confusion, blurred vision
-paresthesia
-hyperactive reflexes
-coma

respiratory acidosis: ABGs

H2CO3 excess in ECF
pH <7.35 (L/acidic)
PaCO2 > 45 (H)
HCO3-: 24-29 (N)
hco3 is wnl w/ acute resp acid bc kidneys don’t have time to comp -> if copd/chronic high bicard and normal pH d/t comp

respiratory acidosis: clinical manifestation

-hypoventilation (primary event)
-dyspnea
-respiratory distress
-H/a, restlessness, confusion
-tachycardia, arrhythmias
-dec LOC, stupor, coma

when a pt goes into respiratory arrest, they become

acidotic bc they are not breathing

respiratory acidosis: causes

not taking good breaths or any
-hypoventilation
-cardiopulmonary arrest
-head injury
-narcotics/sedatives
-anesthesia
-pulmonary disorders
-pain (not taking deep breaths)
-abdominal distension
-airway obstruction
-chest wall deformities
-neuromuscular problems

metabolic acidosis: ABGs

HCO3 deficit in the ECF
pH < 7.35 (L/acidic)
PaCO2: 35-45
HCO3- <24 (L)

metabolic acidosis: causes

-renal failure
-fistulas
-DKA
-lactic acidosis
-prolonged diarrhea (lose bicarb)
-starvation (ketosis)
-shock & cardiac arrest

metabolic acidosis: clinical manifestations

-lethargy, drowsiness, confusion, tremors, muscle cramps, paresthesia -hypotension -hyperkalemia -deep breathing (kussmaul respirations in DKA)

summary of respiratory comp

Rate: rapid Organ: Lungs activity: hyper/hypo vent trigger: met acid-base abnorm

summary of metabolic comp

Rate: slow Organ: Kidneys activity: retention/excretion of H+/HCO3 trigger: resp acid-base abnorm

what do we do for pt w/ respiratory acidosis

-give narcan if drug related -bag mask -intubate **do not give bicarb bc doesn't fix respiratory problem**

what would some w/ respiratory acidosis ABGs look like if they have COPD

**they will be fully compensated** pH: normal PCO2: high HCO3: high

what would we do for a patient with respiratory alkalosis

-calm -anti anxiety meds -breathing into paper bag -rebreather

what will someones ABGs look like in respiratory alkalosis who is fully compensated

pH: normal/basic PCO2: low HCO3: low

what do for someone w/ metabolic acidosis

treat the cause ex: if DKA, bring down BG

what would someones ABGs look like if they have fully compensated metabolic acidosis

pH: normal - acidic PacCO2: low HCO3: low

with compensation, the arrow will always move....

in the same direction as the disorder

what would someones ABGs look like if they have fully compensated metabolic alkalosis

ph: normal PaCO2: high HCO3: high

treatment for metabolic alkalosis

treat the cause so if vomiting give drugs to reduce gastric hydrochloric acid secretions

what is the parameters for the pH to be leaning after compensation has occurred

neutral = 7.4 -leaning toward acidic: <7.4 -leaning toward base: >7.4

uncompensated

pH abnormal, acid **or** base abnormal

partially compensated

pH abnormal, acid **and** base component abnormal

compensated

pH normal, acid or base imbalance is neutralized but not corrected -> arrows moving in same direction

metabolic alkalosis: causes

-taking excess baking soda, alka-seltzer (H shifts out of the cell & K+ goes in causing hypoK) -prolonged vomiting -NG tube suctioning -diuretics (lose H but bicard stays)