gas exchange Flashcards
purpose of ABG’s
to measure acid-base balance in the body
oxygenation
the process of getting O2 into the body
ventilation
the process of eliminating CO2 from the body
respiratory failure as an indication for ABG
- evaluates efficiencty of oxygenation and ventilation
- helps determine if intubation and mechanical ventilation are necessary
mechanical ventilation as an indication for an ABG
- ongoing monitoring of a patients response to the ventilation
- helps guide ventilator settings
- evaluates pt response and readiness to be weaned from ventilator
critical illness as an indication for ABG
- evaluates pt response to treatment and interventions
- assists in prognosing patients condition
pH
normal is 7.35-7.45
- lower than 7.35 is considered acidotic
- greater than 7.45 is considered alkalotic
CO2
lungs/respiratory; normal is 45-35
- greater than 45 is acidotic
- less than 35 is alkalotic
HCO3
carbonic acid; metabolic/kidneys; normal range is 22-26; excreted in lungs; considered a base
- lower than 22 is acidotic
- higher than 26 is alkalotic
H+
metabolic acid; metabolic/kidneys; excreted in kidneys
respiratory acidosis
pH and CO2
increased CO2, decreased pH
respiratory alkalosis
pH and CO2
decreased CO2, increased pH
metabolic acidosis
pH and HCO3
decreased HCO3, decreased pH
- may be caused by a-fib as there is poor perfusion leading to anaerobic metabolism causing lactic acid buildup
metabolic alkalosis
pH and HCO3
increased HCO3, increased pH
respiratory acidosis patho
too much CO2 or carbonic acid caused by hypoventilation
- renal compensation through excretion of H and retention of HCO3
- can be seen in asthma, COPD, pneumonia, pulmonary edema, sleep apnea
respiratory alkalosis patho
too little CO2 (blowing off more than being produced) caused by hyperventilation
- renal compensation by decreased H production and increased HCO3 secretion
- can be seen in MI, asthma, anxiety, COPD, sepsis, DKA, PE
metabolic acidosis patho
too much metabolic acid and get rid of too much base (HCO3); too much acid in body
- increased secretion of H and increased retention of HCO3
- respiratory compensates by hyperventilation
- can be caused by DKA, excessive diarrhea or vomiting, lactic acidosis, HF, seizures, liver failure
metabolic alkalosis patho
too little metabolic acid
- correct through decreased secretion of H and increased secretion of HCO3
- respiratory compensates through hypoventilation
- can be caused by overuse of diuretics, large loss of potassium or sodium in short amount of time
chloride responsive alkalosis
metabolic alkalosis
loss of H by vomiting or dehydration
chloride-resistant alkalosis
metabolic alkalosis
body retains too much HCO3 or shift of H from blood to cells
respiratory acidosis s/s
- hypoxia d/t hypoventilation
- shallow/rapid breathing
- decreased BP
- pale
- hyperkalemia –> dysrhythmias
- dizzy
- muscle weakness
respiratory alkalosis s/s
- seizures
- deep breathing/rapid
- hyperventilation
- tachy
- decrease or normal BP
- hypokalemia
- numbness
- lethargy
- light headed
- n/v
metabolic acidosis s/s
- decreased BP
- hyperkalemia
- muscle twitching
- vasodilation (warm/flush skin)
- n/v
- decreased muscle tone and reflex
- hyperventilation
metabolic alkalosis s/s
- restlessness followed by lethargy
- dysrhythmias (tachy)
- hypoventilation
- confusion
- n/v
- tremors, tingling, muscle cramps
- hypokalemia
full compensation
pH presents as normal
- body is correcting the imbalance
partial compensation
all 3 values (pH, CO2, HCO3) are abnormal
- body is attempting to correct the imbalance
uncompensation
CO2 or HCO3 is within normal limits and the other value
(CO2 or HCO3) is abnormal ‘
- body has made no attempt to correct
outcomes when compensatory mechanisms fail
- altered cell function, esp in brain
- change in intracellular enzyme activity causing cell dysfunction
- decreased LOC caused by acidosis
- decreased LOC and other neuro manifestations caused by alkalosis
potassium and acidosis
shifts out of cell into blood (swaps with H) and causes hyperkalemia
potassium and alkalosis
H switches to ECF and K moves in to cell or becomes excreted causing hypokalemia
- remember “K-low sis”
treatment/intervention for metabolic acidosis
hemodialysis, NaHCO3 admin
treatment/intervention for metabolic alkalosis
- sodium chloride in chloride responsive alkalosis
- diamox which increases HCO3 excretion
- hemodialysis
preventative interventions for respiratory acidosis (hypoventilation)
- bronchodilators
- CPAP/BiPAP, give O2, ventilator
prevention of respiratory alkalosis (hyperventilation)
breathe into paper bag to re-breath CO2, pursed lip breathing
left lung
2 lobes
right lung
3 lobes
lung anatomy
bronchi –> bronchioles –> alveoli
- apex: top of lungs
- base: bottom of lungs
parietal pleura
covers body wall
visceral pleura
covers lungs
pleural fluid
between the 2 pleura to decrease friction
Asthma
exaggerated hypersensitivity response to allergens, exercise, etc..
COPD
airway obstruction due to hyperinflation, mucus hypersecretion, gas exchange abnormalities
pneumothroax
presence of air in the lungs
- common in young, tall, thin males
- closed: air moves from alveoli into pleural space
- open: air enters in inspiration and exits during expiration
tension pneumothroax
pleura acts as one way valve where air can enter but cannot exit
- look for mediastinal shift to their left side
PE
caused by DVT
- s/s are chest pain, SOB, low O2
- need CT to diagnose
crackles
popping sounds; more
- common during inspiration
- can be coarse or fine
wheezing
continuous; high or low
- more pronounced on expiration
DKA
no insulin in the body and breaks down fats which releases ketones; glucose stays in blood
- hyperglycemia
- keotsis
- acidosis
acute pancreatitis
does not lead to chronic unless complications develop
- can be caused by alcohol abuse or gallstones
chronic pancreatitis
inflammatory disorder caused by progressive destruction on pancreas
cholecystitis
inflammation of gallbladder which can be caused by bacteria, alterations in fluid and electrolytes, and bile stasis
- increase in WBC will be seen
gallbladder location
right side of abdomen just beneath liver
sepsis
innapropriate and extreme systemic response to infection; pathogen in organ or blood leads to extreme vasodilation and hypoperfusion –> can lead to activation of coagulation system which then forms clots whether or not there is bleeding due to cytokines
- can be a product of respiratory alkalosis
atelectasis
collapse of alveoli where there is not enough ventilation but perfusion is adequate
- increased risk for hypoxia
chronic bronchitis
type of COPD
chronic productive cough greater than 3 months
- inflammation and secretions of bronchioles
emphysema
type of COPD
airspace in alveoli is increased and alveoli walls are stiff leading to trapped air
cardiogenic pulmonary edema
increase in capillary hydrostatic pressure and pulmonary circulation backs up into the lungs
- leading and related to left sided heart failure
ARDS
occurs within 1 week of respiratory changes from original event relating to inflammation
- increased CO2 in blood, decreased O2 inhalation leading to hypoxemia and hypercapnia
