NURS 460 - Pulmonary Basics, V/Q Mismatch, Oxygen Dissociation Curve

acute lung injury is an issue with

exchange of O2 and CO2

severe ALI is common in

ICU

ALI can cause symptoms of

multiple organ distress syndrome (MODS)

in acute respiratory distress syndrome, lungs are

stiff and wet

ARDS are caused by

diffuse alveolar damage causing profound hypoxia

what ABG is decreased with ARDS

PaO2

in ARDS, pt have problems with

compliance and recoil

what is the most severe type of ALI?

ARDS

gas exchange occurs through

alveolar capillary membrane

ventilation involves

musculoskeletal and nervous systems

ventilation is a

mechanical act of movement of air in and out

we breathe on a ____________ pressure system

negative

main muscle in ventilation is the

diaphragm

when the diaphragm flatten, air is

sucked in

when diaphragm relaxes, we

passively blow air out

respiration is the

transport of O2 and CO2 between the alveoli and pulmonary capillaries (alveolar capillary membrane)

functions of respiratory system

ventilation and respiration

chemoreceptors are a part of the

SNS

chemoreceptors increase or decrease breathing based on

CO2, O2, and H+

ventilation is usually controlled by chemoreceptors monitoring

CO2 levels

increased CO2 means increased

breathing

what muscles support the diaphragm?

intercostal muscles, scaline, and sternoclidomastoid

what 3 things make up the work of breathing?

compliance, recoil, resistance

what is compliance?

ability of lungs and thorax to stretch and expand given a change of pressure

compliance is decreased in pts with what diseases specifically?

pulmonary fibrosis and ARDS (stiff)

compliance is increased in pts with what diseases specifically?

emphysema and COPD

what is recoil?

how well the lungs return to their original state after exhalation

recoil is decreased in what diseases specifically?

ARDS and COPD

why do pts with COPD have good compliance but bad recoil?

good compliance bc they have a barrel chest - can expand but can't recoil bc of the barrel chest

resistance has to do with

size of airway

airway resistance will increase when

the airway is constricted (asthma, oral ETT, bronchoconstriction)

respiration occurs because of diffusion from a _______ to _______ concentration

high (in alveolus) to low (in capillary)

normal unit (V/Q mismatch)

normal ventilation and perfusion

physiologic shunt (V/Q mismatch)

ventilation < perfusion

blood flow is good, but ventilation is not

causes of physiologic shunt

pneumonia (fluid blocking alveolis), atelectasis (alveoli sticky, so when they collapse, they don't open again)

encourage what with physiologic shunt

coughing and deep breathing

alveolar dead space/high-ventilation-perfusion ratio (V/Q mismatch)

ventilation > perfusion

air goes in and out, but perfusion is blocked

part of the lung looks like this, not the whole long

causes of V>P mistmatch

pulmonary embolus, pulmonary infarct, some type of blockage

silent unit (V/Q mismatch)

little to no ventilation nor perfusion

what causes silent unit mismatch?

severe ARDS (pt's lungs are wet, so fluid is blocking alveolis), pneumothorax (air enters thoracic cavity and presses on lungs and prevents alveoli from blowing up and puts pressure on blood flow to stop bloodflow in that area)

if a patient has ARDS, they are probably ________ which is causing the low blood flow in a silent unit

septic

what is PaO2?

partial pressure of oxygen dissolved in arterial blood

normal PaO2

80-100 mmHg

PaO2 decreases in the

elderly

<60 PaO2 =

treat

<50 PaO2 =

intubate

what is SaO2?

amount of oxygen bound to hemoglobin

normal SaO2

92-99% (can't go over 100%)

SaO2 measured by

pulse oximetry (SpO2) but can see precise number on ABG

fxn of Hgb

carries O2 through body and delivers to tissues

normal pH

7.35-7.45

what is affinity?

capacity/ability of Hgb to combine with O2

what is high affinity?

Hgb latches onto O2 in the alveolar-capillary membrane but doesn't let it go into tissues - tissues are hypoxic

high affinity pH

7.46+

alkalotic pt

another name for high affinity

greedy Hgb

what is low affinity?

Hgb doesn't pick up O2 at the alveolar-capillary membrane, but it does release all the oxygen it has to the tissues

low affinity pH

7.26-7.34

other name for low affinity

good Samaritan Hgb

what is low-low affinity?

hgb doesn't bind with oxygen in lungs, and it doesn't release oxygen in tissues

-does no work, just flows through

low-low affinity pH

<7.25

another name for low-low affinity

lump on a log

pts with a low-low affinity will have a very high

lactic acid

out of all of the affinities, which one would be the 'best' to have?

low affinity bc oxygen is still getting to the tissues, but this isn't sustainable and won't last long

purpose of the oxyhemoglobin dissociation curve

assists nurses to understand the pt's tissue oxygenation

_____% of oxygen is carried in SaO2

97%

_____% of oxygen is dissolved in PaO2 in serum?

3%

what affinity is in the left shift oxygen dissociation curve?

high

left shift oxygen dissociation curve means oxygen is picked up in the

lungs

-Hgb attaches to as much oxygen as possible in the lungs but gives nothing to tissues

left shift oxygen dissociation curve - alkalosis or acidosis?

alkolosis

pH 7.46+

left shift oxygen dissociation curve temperature?

low - hypothalamus response

left shift oxygen dissociation curve CO2?

low CO2 d/t breathing off CO2

<35 mmHg

what might a pt look like in a left shift oxygen dissociation curve?

pale, blue, mottled

what affinity is in a right shift oxygen dissociation curve?

low affinity

7.26-7.34 pH

right shift oxygen dissociation curve means that the oxygen is being

released in the tissues/muscles but not being picked up in the lungs, so tissues still require more oxygen

low affinity/right shift oxygen dissociation curve will eventually turn into

low-low affinity and fall off the curve - there is only a finite amount of O2

right shift oxygen dissociation curve temperature

rise in temp - hypothalamus response

right shift oxygen dissociation curve CO2?

rise in CO2 ; >45

Hgb doesn't bind with oxygen in lungs but gives it to tissues

geriatric considerations for increased function of respiratory system (this is a bad thing - it means increased worsening)

-V/Q mismatch

-AP diameter

-Residual volume

geriatric considerations for decreased function of respiratory system

-cough and laryngeal reflexes decreased so pt gets pneumonia easily

-mucociliary escalator function

-alveoli

-respiratory muscle strength

when older adults develop respiratory failure, they often manifest non-specific symptoms of hypoxemia such as:

-agitation

-confusion

-disorientation

-lethargy

-dyspnea

-chest pain

first sign of respiratory failure in elderly

change in LOC/mental status, AMS