-
arterial blood gas norms
ph?
pco2?
hco3?(bicarb base)
increase number =basic
- ph-7.35-7.45
- pco2=35-45
- HCO3=21-28
-
ph range in humans
- heart rate will stop
- hypothermia(heart shuts down)
- hyper(brain shuts down)
-
PH definitions
- hydrogen ion concentration
- -measured by ph scale
- --log{H+}
- -1-14
- acidity(ph<7) lower #
- alkalinity(ph>7) higher #
- more free h more acid
- a free h will change ph
- strong acid=fall apart easy H falls off
-
Where do acid/base comes from?
- acid ingestion
- -ASA(asprin)
- -FeSO4(iron sulfate)
- -paraldehyde(antibuse-trying to break addictions)
- *base ingestion(alkaline)-bicarbonate ph increase=alkolosis
- -antacids-TUMS ca+ carbonate
- -citrate(blood preservative)-blood transfusions ph will increase
- -lactate(counteract acidity)
-
Where do acid/base comes from?
- CO2 build up
- -co2 converted to carbonic acid (stop breathing stays in body and converts acid)
- *Metabolic waste products
- -lactic acid (carbs, protein ..anaerobic metabolism)
- -keto acids (fats )
resp arrest-lactic acids builds up(anaerobic) and co2..gives bicarbonate
-
where do acids and base go>
- acid loss : gastric suction, gastric vomiting
- alkali loss : diarrhea(huge amounts of base)why it burns skin , intestinal vomiting
-
regulation of acid/bases
- buffers
- -1st line of defense
- -temporary
- -chemically inactivates H+
- -always there..temporary grabs free h and binds it to something
-
buffer systems
inside cells
- phosphate*** can buffer carbonic acid
- proteins(hemoglobin)-buffers carbonic acid
-
buffer systems
inside cells
- carbonic acid/bicarbonate system(can't buffer own components ..can do ASA, citrate can't buffer co2)
- -can't buffer carbonic acid
- -important because of large amounts of co2 produced daily
-
carbonic acid/bicarb system
(BLOOD)
- must maintain
- 20 parts HCO3 to one part H2CO3 ratio for homeostasis
- (change ratio change ph)
- lungs: regulate h2CO3 (acid regulation)
kidneys: regulate hco3- (bicarb base regulator)
-
LUNGS: 2nd line of defense
- most rapid
- only minutes from co2 production to co2 elimination
- controlled by respiratory center in medulla
- speed up rr to get rid of acid(exhaling more)
- save acid--breath slower RR , limited in how much lungs can do because of the need of 02
-
example of mechanism
- exercise increase in acid production (lactic acid increases RR)
- medulla sense increase in acid(monitor co2 levels)
- tells lungs to speed up
- lungs blow off co2
- acid levels drop
what kills people, because brain is sedated..the brain can't tell the lungs what to do , acidic..lungs are also under voluntary control
-
taking in a deep breath causes ??
- alkolosis -- you lose acid
- dizzy
-
Kidneys: 3rd line of defense
- Regulate HCO3 (base) side of the equation
- may take several days
- very powerful
- act by: reabsorb HCO3, secrete h+ in urine(ammonia) (decreases acid)
-
Respiratory disorders: ACIDOSIS
etiology?
- CO2 retention
- -pneumonia(gas exhange) -alveoli lined with mucous ..barrel chest
- -emphysema, burns(obstruction)
- -chest trauma, polia(NM function)
- -drug overdose, etoh(medulla fx) ..medulla is sedated
ribs goes horizontal due to co2 levels (trapping air) -expand to support structure of lungs ..change and ribs try to accommodate
-
respiratory acidosis
sx?
- symptoms: CNS DEPRESSION(result of ph change)
- -disorientation, coma
- dyspnea
- -tachycardia
- -arrhythmias
- -co2 narcosis(excessive co2) birhgt red
- cause resp problem
-
CO2 narcosis
- respiratory drive becomes insensitive to long term co2 elevation
- medulla uses hypoxia as respiratory trigger
- meed to maintain some degree of hypoxia to keep breathing
- breath runs on co2 levels co2 driver RR
- emphayzeema increases co2 brain then learns to respond to 02 changes ..if you give 02 the resp rate decreases ..limit amounts of 02"keep air hungry"
-
ABG indicators of resp acidosis
acid =depression
- ph- decrease
- co2-increase
- hco3-ultamilty it will save base ..increase ..kidney
-
RESP ACIDOSIS nursing care
- improve respiratory function
- correct acidosis(NaHCO3-high risk of rebound alkalosis.....(overdose of base causes tetny-muscle rigidity ..begins with twitching hyper reflex ...) then give Ca+ to correct )
- IV ringers lactate or NaLactate
- NG suction(sucking acid out of stomach)
Correct other electrolyte imbalance (hyperkalemia(causes arrhythmia problems) or chloride deficit
-
To prevent acidosis take immediate action
take a deep breath and relax
-
REspiratory ALKALOSIS
etiology
- hyperventilation
- overstimulation of respiratory center
- -pain, trauma, hyperstimulus of brain(drugs), panic
- -exhaling too often and too deep
-
resp alkalosis
- cns-irritable
- hyperreflexia- jittery, reflexes are super active
- paresthesia-tingling, numbness, circumoral, extremities, fingertips
Potassium will be low...
-
RESP alkalosis nursing care
- treat underlying disorder
- -sedatives
- -breath into paper bag(not if hypnotic, used for anxiety induced hyperventilation)
- -pain management
- -oxygen therapy
- -change ventilator settings(may be too high)
-
where did the potassium go?
k goes inside cells so H ions can come out to solve the acid deficit
-
METABOLIC ACIDOSIS
causes:
- overproduction of acids( DM, hyperthyroid...too much metabolic..lactic acid and keto acids--breath will smell sweet)
- excessive ingestion( salicylate(aspirin), paraldehyde, antibus)
- renal disease
- loss of alkali(base...diarrhea)
- tissue anoxia(anaerobic--lactic acid = shock)
-
METABOLIC ACIDOSIS
sx
- CNS is depressed
- fruity breath=ketones..DM...can be mistaken for drunks
- nausea/diarrhea=causing the problem
- Potassium level is high=h+ going int0 cell K+ going out
- 02 level=normal most likely
- co2=low-->high resp rate
-
Metabolic acidosis severe sx
- Kussmaul respirations- is a result and hyperventilation to blow of co2
- flushed, warm, dry skin=blood vessels dilate in presence of acidosis(more blood to the lungs to exhale more)
- stupor.coma=dehydrated, dumps sugar into urine ..pulls water with.
-
metabolic acidosis nursing care
- restore blood volume
- correct bicarbonate deficit(NaHCO3) (beware of rebound alkalosis)
- NG suction
- treat electrolyte problems= increase K+, low HC03,
- protect from injury=dehydrated, unstable, confused
- dialysis-esp if renal induced problem
- insule/saline=used temporary fix for hyperkalemia( grabs sugar and gets into cell with a K+, temporarily lowering potassium..
if tenty(from rebound alkalosis) give CA iv
-
metabolic ALKALOSIS
losing acid...too much base
- vommiting
- ng suction
- diuretics(losing acid from kidney)
- hypokalemia( decrease K , cause or result
- ingestion of bicarb(baking soda)
- massive blood transfusion(citrate-preservative in blood)
-
metabolic ALKALOSIS sx
- CNS- irritability , tingling in fingers
- polyuria-if caused by diuretics ..may add to hypokalemia
- dysrhythmias-low K, heart doesn't like any changes in K ..heart will increase or decrease
- tetany=muscle rigidity , stiff muscles, hyper reflexes, ALWAYS ON EKG
-
Met ALKALOSIS lab values
- ph=high
- pco2=high(lungs slow down to save acid immediately)
- hco3=hight
- o2=may be low
SLOW resp
-
Met ALKALOSIS nursing care
- treat primary problem
- -ingestion
- -volume depletion(diuretics)
- control alkalosis
- ringers solution(chloride )
- ammonium chloride(beware rbc hemolysis)=last effort..acid to treat base prob
- treat other deficits(K, NA, cl)
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