Acid/base

what do alterations in pH do

disrupt boy functioning especially protein structure and function

whats the narrow range blood pH has to be

7.35-7.45

what helps prevent large changes in pH

Buffer systems

Hydrogen ions are acidic so they are donated when the solution is

too basic

Hydrogen ions are acidic so they are absorbed when the solution is too

acidic

compound that donates H+ ions

carbonic acid (H2CO3) and carbon dioxide (CO2)

acid

compound that accepts H+ ions

bicarbonate (HCO3) accepts hydrogen ion

base

represents the concentration of H+

inverted relationship the more H+ the lower the pH and vice versa

pH

what are the two acid forms are in the body

volatile and non volatile

CO2 combines w/ water forming the volatile acid carbonic acid (H2CO2)

enzyme- carbonic anhydrase in RBCs

H2CO3 dissoatiates into CO2 and water

CO2 exhaled by the lungs

(needs lungs to be working

volatile acid

not converted to CO2

excreted by kidneys

ketones lactic acid etc (fat metabolism)

need kidneys to be working

negative logarithm of H+ concentration -log

pH

lower pH value

more acidic

higher pH value

more basic

very strong acid but low concentrations compared to other acids in body fluids

H+

CO2 (volatile)- combine with H2O H2CO3

ketones formed when body iis starved of glucose begins using ketones from the liver

lactic acid- pyruvic acid from protein synthesis lactic acid = emergency backup

metabolic acid example

metabolism of negatively charged amino acid

hydrolysis of phosphates (when water breaks ATP bond produce

building up and breaking down of amino acid to support protein synthesis

metabolic bases

what are the three major buffer systems in the blood

1st line of defense against changes in the bodys pH

Absorb or donate H+ ions to prevent blood pH changes

protein

phosphate

carbonic acid bicarbonate buffering

largest buffering system in the body (amino allow protein to donatr/absorb H+ ion)

hemoglobin- bind H+ ions as needed

one of the primary proteins carrying out this function

protein

regulate intracellular pH

key role in regulating fat environment (can take basic or acidic form)

phosphate

involves carbon dioxide (CO2) carbonic acid (H2CO3) hydrogen ion (H+) bicarbonate (HCO3)

lungs and kidneys utilize this system to help maintain blood pH

kidneys are the first thing considered w/ acid excretion but lungs are the major organs because they can expel CO2

carbonic acid - weak ones

carbonic acid bicarbonate buffering

bicarc is not something the body is trying to excrete in most cases because ——— typically store it it can also excrete H+ions and generate new bicarb when needed

kicks in need lungs and kidneys

CO2 + H20←→ H2CO3←→H+ + HCO3-

goal is equilibrium

equation goes both ways

carbonic acid bicarnate system

H2CO3

carbonic acid

HCO3-

bicarb (weak base)

enzyme in erythrocytes (helps catalyze reaction)

carbonic anhydrase

carbon dioxide combines w/ water to form

carbonic acid

carbonic acid dissociates ibto

bicarbonates and hydrogen ions

H+ is a

strong acid

HCO3- is a

weak base

when CO2 is elevated -

More HCO3- + H+ are formed

CO2 → bicarb

so it can be transported

equation moves toward the right

when H+ ions are elevated H2CO3 ions are converted to CO2 and H2O

Co2 exhaled

equation moves to the left

more H+ added blood becomes more acidic

H+ removed blood becomes more basic

the reaction can shift left and right depending on the bodys needs

Carbonic acid bicarbonate system

control bhow much CO2 is breathed out

fast pH control 9minutes

not sustainable

lungs

reabsorb or excrete HCO3; excrete H+

slow pH control (hours to days)

kidneys

Protein and phosphate act immediately

limited capacity compared to lungs and. kidney

other buffers

if Co2 is high reactions shifts to the—- and the respiratory rate increases

right

if Co2 is low the reaction shifts to the —- and respiratory rate decreases

left

what is the secondary line of defense

respiratory compensation

Co2 exhaled H+ concentration fall and PH raises causing —-

basically —— reduces CO2 and diminishes H+ and raises pH

hyperventilation

retention of CO2 H+ concentration elevated and PH lowers ——-

— causes retention of CO2 which increases H+ ion levels and decreases pH

hhypoventilation (overdose too much CO2)

lung response cannot be maintained

indefinitely

partial pressure of CO2 (PaCO2)

35-45 mmHg

the brain closely monitors H+ levels and alerts the —- (brainstem/respiratory center) to adjust ventilation

medulla

3rd line of defense

renal compensation

what are the 3 roles in regulation

reabsorption of HCO3(bicarb) has filtered through glomerulus

excretion of H+(acid) resulting from metabolism diluted/excreted through urine

production of new HCO3 released back into blood (recycled through kidney)

if pH is too acidic the kidneys

retain HCO3- and excreate H+

if pH is tto basic kidneys

retain H+

and excrete HCO3-

the renal compensation occurs in the

renal tubules

hrs to days to compensate

response maintained for longer - unlike the lungs which is unattainable for long periods

pressure of O2 in the arterial blood (90-100 mmHg)

PaO2

pressure of carbon dioxide in arterial blood (35-45 mmHg)

PaCO2

amount of bicarbonate ion in the blood

22-26 mEq/ liter

HCO3-

saturation of HgB w/ O2 (95-100%)

pulse oximeter

base excess or deficient - measures all buffer systems of blood too much base or deficient of base

SaO2

measure of the balance between cations and anions in the blood

cations minus anions

(Na+ and K+) - (Cl- and HCO3-)

anion gap

anion gap is ussually

equal

the difference between the measured cations and anions

unmeasured anions

normal anion gap

8-16 mEq/ L

deviation in anion gap can help to differitiate forms of

metabolic acidosis

increased anion gap

large amounts of unmeasured acids enter blood stream

ex- ketones in diabetic ketoacidosis

bicarbinate levels fall as bicarbinate ions (measured anions) buffer the acid

normal anion gap

the bloodstream normally has a certain level of unbound anions called —— when bloodstream has an increased number of acids as in DKA the anion gap is increased

some forms of metabolic acidosis such as GI loss of bicarb do not have elevated anion gap

lactic acidosis

ketoacidosis

renal failure

overdose of aspirin (acetylsalcylic acid (ASA)

ingestion of methonol or ethyline glycol

elevated anion gap

GI loss of H3O3- (could have all other signs of metabolism acidosis→ increased bicarbonate loss due to basically lossof base does not alter it diarrhea

increased release HCO3 loss

hypoaldosteronism

ingestion of ammonium chloride

hyperalimentation

normal anion gap

changes in PH affect ion (electrolyte) movement

changes in ion (electrolyte) concentration can also affect pH

K+ and Ca+

some of the symptoms associated w/ pH imbalances are due to electrolyte disturbances

electrolytes

K+ and H+ are —

and move freely between ICF and ECF

changes in concentration in one affects movement in the other

positively charged

H+ shifts into cells and K+ shifts out of cells leading to hyperkalemia

electrolytes would show increased potassium levels

acidosis (especially metabolic)

k+ ions shift into cell from plasma leading to hypokalemia

alkolosis

H+ shifts out of cells leading to acidosis

hyperkalemia

H+ shifts into cells leading to alkalosis

hypokalemia

when the kidneys and lungs cannot maintain acid base balance any of more the four acid base imabalances occu

lungs and kidneys

respiratory acidosis

pH <7.35 PCO2 >45mmHg

high acid low pH

inadequate exhange of CO2 w/in the lungs leading to CO2 elevation (hypercapnia)

lungs are unable to remove sufficient CO2 cauing it to accumukate in the bloodstream

moves quation to the right

caused by interference w/ breathing (COPD, respiraory muscle weakness, suffacation, trauma, overdose)

compensation occurs by kidneys reabsorbing HCO3 and excreting H+ ions however the kidneys take hours to days to accomplish this so medical intervention is needed → intubation, mechanical ventilation

presents with restlessness headache rapid breathing lethargy SOB wheezing

can develop confusion carbon dioxide narcosis

obstructive lung disease may be cause (COPD)

respiratory center (medulla0 may become insensitive to chronically high CO2

respiratory acidosis

pH greater than 7.45

PCo2 less than 35 mmHg

respiratory alkalosis

pH high acid low

often due to hyperventilation

stress anxiety drug toxicity head injury (often told to breathe in bag breathe CO2. back in)

reduction in CO2 and H+ levels can be caused by breathing too fast as in anxiety hyperventilation pneumonia

moves equation to the lef t(CO2 low)

hypercalcemia and hhyperkalemia may develop effect on excitability of muscles (arrythmia, GI function0

free ionized (at in the blood rushes to fill the binding sites on albumin after H+ has been released to correct the alkalosis (making it more acidic)

K+ moves ito the cell to replace the H+ that left to correct the alkolosis and tgerefore the K+ serum levels drops

clinical manifestation is

feeling lightheaded parathesis (tingling in extremities pin and needles) altered consiousness muscle spasm tetany confusion if hypoxic can develop cyanosis

the bodys attempt to compensate kidney attempt to reabsorb maxximum H+ and excrete HCO3-

takes hrs to days so medical intervention is needed decrease clients breathing rate increase CO2 (CO2 rebreathing breathe into paper bag non rebreather mask

respiratory alkalosis

excess of acid not related to CO2

pH less than 7.35 w/ normal to low CO2

HCO3 less than 22 MEq/L

same direction base low and pH low

metabolic acidosis

causes increased acidsin blood decreased excretion of acids lossof base from blood toxic ingestion of acidic substances (ASA)- lactic acidosis (anaerobic metabolism)

excess acid- lactic acidosis (byproduct of anaerobic metabolism) ketoacidosis of diabetes (DKA) renal failure causing acid waste buildup

bicarbonate loss- kidney disorders GI disorders prolonged diarrhea w/ loss of bicarb

may be present w/ normal or elevated anion gap increased caid =increase anion gap loss of base no charge

helps providers to determine cause of imbalance

hyperkalemia and hypercalcemia may develop hydrogen takes all place on albumin

clinical manifestation kussmauls breathing (deep rapid respirations) disorientation/ confusion coma, dysrhythmia, tachycardia, hypotensionheadache seizures nausea vomiting dehydration

the bodys attempt at compensation the lungs increase ventilation to try to blow off Co2 kussmaus breathing however the lungs can only increase ventilation so much

kidneys excrete H+ reabsorb HCO3- hrs to days moving to left

mdical intervention needed IV bicarb correct underlying cause

metabolic acisosis

pH is greater than 7.45 q/ normal or high CO2

HCO3 greater than 26

pH high bicarb high

metabolic alkalosis

excessive loss of acids unrelate dto CO2

most common cause is depletion of H+ ions diuretics (loss of K ions H+ shift into place)

kidneys unable to retain H+ or excrete HCO3- and GI tract loss (vomiting NG sunctioning bulemia 0

increase in bicarb levels (antacids) tums- post cose excess bucarb IV

hypocalcemia and hypokalemia may develop

clinical manifestation dysrhythmia paresthesia lightheaded to confusion muscle weakness diarrhea weakness agitation

compensation- lungs decrease ventilation to increase Co2

kidneys excrete HCO3 and retain H= the kidney will reabsorb H+ instead of its usual K+

therefore hyperkalemia occurs w/ metabolic alkalosis

tx- electrolyte and fluid replacemnt

respiratory

opposite

metablic

equal

ROME

compensation- -which side of 7.4

compensation

only on system abnormal - ph not normal

uncompensated

both systems abnormal pH still abnormal

partially compensating

whichever component (respiratory or metabolic) pushes the pH in the sma edirection (acidic or alkalotic) identifies the primary cause

fully compensatied

both systems abnormal pH normal (7.35-7.45)

primary cause compensatied ABGS

step 1- identify pH

if normal range- 7.35-7.45→ fully compensatied

which side of 7.4

match the pH direction

the one that matches teh pH direction → primary cause

so if less than 7.4 acidic

if above 7.4 alkalosis

nmatch pH direction

steps for rome interpretation

1. assess pH <7.35-acidodis >7.45- alkalosis

2. asses PaCO2 if it indicates repiratory effect >45 - acidosis. <35alkolosis (respirtory opposite)

3. assess HCO3- metabolic affect <22- acidosis >26 alkolosis

4. the apply ROME if pH and PaCo2 are opposite→ respiratory

5. if pH and HCO3 move in same direction → metabolic

6. then determine comensations

7. uncomesatied if one system is abnormal and the pH is not normal

8. partially compensated if both systems are abnormal and pH still abnornal

9. fully compensated- both systems pH is normal (7.35-7.45)