Pathophysiology Unit 2 Exam

acid

donates H+ in solution

form majority of acids

acidic solutions

volatile acids

• CO2+ H2O= H2CO3 (Carbonic Acid)

• converted back to CO2 and breathed off

nonvolatile acids

acids not converted to CO2

base

accepts H+ in solution

form majority of bases

alkaline/basic solutions

what is used to calculate pH

CO2 measurements

what is expressed as pH

H+ concentration

what are buffer pairs/systems

acids and bases

respiratory control

• second line defense

• chempreceptors in brainstem, corotid/aortic bodies

• CO2 sensors

• rapid response, max in 12-24 hours

renal control

• third line defense

• excrete H+ (protein/fat metabolism)

• reabsorb HCO3-

• produce new HCO3-

• slower response, lasts days

CO2 is carried in the ____ _______ attached to hemoglobin

vascular circulation

pH is bufered by...

lungs and kidney primarily

3 primary pH buffer systems

• bicarbonate

• protein

• H+-K+ exchange

bicarbonate buffer system

• most powerful ECF buffer

• primary compensory system

• H2CO3- buffer moves both ways

  • shift right: excess CO2, access more H+ → acidosis

  • shift left: excess H+, create/exhale more CO2→ alkalosis

protein buffer system

• largest buffer system

• hemoglobin primary protein carries H+

• amphoteric

• albumin and plasma globulins in vascuar compartment

amphoteric

function as an acid or base

H+-K+ exchange buffer system

• move freely between ICF and ECF

• K+ shift more pronounced in metabolic acidosis

bone pH buffer system

• H+ exchange for Na+ or K+ on bone surface

• bone dissolution —> NaHCO3 and CaCO3 can buffer acids

• greater role in chronic acidosis

• bone demineralization, develop kidney stones

blood pH job

ECF- narrow balance

PCO2 job

assesses respiratory component

HCO3 job

buffer

anion gap job

• difference between cations and anions

• diagnose metabolic acidosis

normal range blood pH

7.35-7.45

normal range PCO2

35-45 mmHG (arterial)

normal range HCO3

22-26 mEq/L (arterial)

normal range anion gap

8-16 mEq/L

the ability of the body to maintain pH within normal physiologic range depends on which of the following?

• renal mechanisms

• respiratory mechanisms

acidosis

additon of excess H+

alkalosis

removal of excess H+

compensation

• renal for respiratory

• respiratory for metabolic

respiratory acidosis simplified

low pH, high PCO2, normal HCO3

common cause of respiratory acidosis

respiratory depression (drugs, CNS trauma), COPD, pneumonia

respiratory alkalosis simplified

high pH, low PCO2, normal HCO3

common cause of respiratory alkalosis

hyperventiliation (emotions, pain)

metabolic acidosis simplified

low pH, normal PCO2, low HCO3

common cause of metabolic acidosis

diabetes, shock, renal failure

metabolic alkalosis simplified

high pH, normal PCO2, high HCO3

common cause of metabolic alkalosis

sodium bicarbonate overdose, prolonged vomiting, NG drainage

etiology of metabolic acidosis

• abnormal accumulation of acids

• abnormal loss of bases

• low pH and HCO3, < 22 mEq/L

how does metabolic acidosis occur

• lactic acidosis

• diabetic ketoacidosis

• renal failure

• salicylate toxicity

• excessive HCO3 loss (diarrhea, intestinal suction)

• increased Cl- levels (renal resorption, NaCl infusions)

• methanol and ethylene glycol (converted to acids in body)

clinical manifestations of metabolic acidosis

• results from underlying conditon or disease

• nausea and vomiting

• weakness, lethargy

• confusion

• stupor

• cardiac arrhythmias

• skin warm, flushed

• increased respirtions

• acid urine

• interferes with Ca++ absorption

treatment for metabolic acidosis

• correct underlying disorder

• IV of HCO3

etiology of metabolic alkalosis

• loss of H+ or an addition of base to body fluids

• high pH 7.45, HCO3 → 26 mEq/L

how does metabolic alkalosis occur

• excessive ingestion/infusion HCO3

• citrate-containing blood transfusions

• gastric suction

• binge-purge system

• severe hyperkalemia

• diuretic therapy

• milk-alkali syndome

• loss of body fluids

clinical manifestations of metabolic alkalosis

• confusion

• hyperactive reflexes

• tetany

• convulsions

• hypotension

• arrhythmias

• decreased respirations

treatment for metabolic alkalosis

• correct cause

• replace K+

etiology of respiratory acidosis

• impaired alveolar ventilation

• retaining CO2 (CO2 > 45) (hypercapnia), pH < 7.35

how does respiratory acidosis occur

• airway obstruction, aspiration

• head injury

• drug-induced CNS depression

  • alcohol, narcotics, IV sedation

• CNS injury

• pulmonary disease

  • pneumonia, edema, COPD, emphysema

  • respiratory distress syndrome

• pneumothorax, flail chest

• extreme obesity

treatment for respiratory acidosis

improve ventilation

clinical manifestations of respiraory acidosis

• headache

• weakness

• behavior changes

• hallucinations

• tremors

• confusion

• paranoia

hypocapnia

PCO2 < 35 mmHG, HCO3 < 22 mEq/L, pH > 7.4

how does respiratory alkalosis occur

• excessive ventilation → hyperventilation

  • panic attack, anxiety

• stimulation respiratory center

• elevated blood ammonia

• encephalitis

• fever

• mechanical ventilation

• transitory at altitude → kidneys excrete HCO3

clinical manifestations of respiratory alkalosis

• dizziness

• panic

• light-headedness

• tetany

• positive Chvostek and Trousseau signs

• seizures

• cardiac arrhytmias

treatment for respirtatory alkalosis

• correct underlying cause

• supplemental O2

• adjust mechanical ventialation settings

• reassurance

PaCO2 is the ____ component, and HCO3 is the ___ component

oxygenation, metabolic

HCO3 is primarily controlled by the ____

kidneys

what is pH critical for

• oxygen delivery

• protein structure

• biocemical reactions

acidosis (pH)

pH less than 7.35

alkalosis (pH)

pH greater than 7.45

acidosis (CO2)

CO2 greater than 45

alkalosis (CO2)

CO2 less than 35

an increase in CO2 would cause the pH to become more…

acidic (respiratory)

acidosis (HCO3)

HCO3 less than 22

alkalosis (HCO3)

HCO3 greater than 26

an increase in HCO3 would cause the pH to…

increase

Brady

too slow

tachy

too fast

a-

without/not

dys

difficult

ortho

straight

plea

breathing

bradypnea

breathing too slow, < 12 per minute

tachypnea

breathing too fast, > 20 per minute

apnea

not breathing

dyspnea

difficulty breathing

orthopnea

difficulty breathing while lying down straight

hyper

high

hypo

low

pneum/o

air/lungs

hem/o

blood

pharyng/o

pharynx

bronch/o

bronchi/us

bacter

bacteria

acid

acidic

alka

alkalotic

laryng/o

larynx

naso/rhino

nose

cyan

blue

ox

oxygen

capnia

carbon dioxide

emia

in the blood

optysis

cough/expectorate

osis

condition

itis

inflammation

upper respiratory tract anatomy

• colonized with normal flora

• warms, filters, and humidifies air

lower resporatory tract anatomy

• sterile

• protects and cleans

• controls airflow

• gas exchange occurs in alveoli

mucociliary apparatus

• carpet of hairlike projections lining bronchioles, bronchi, trachea, and sinuses

• beat downward/upward moving particles toward the throat to be swallowed

• damage increases infection risk

ventilation

air movement

perfusion

blood flow