oxygenation, circulation, perfusion - fundamentals

describe oxygenation

movement of O2 from the air into the body at alveolar-capillary membrane by way of diffusion

describe circulation

heart acts as a pump pushing blood through the pulmonary and systemic circuits to support tissue perfusion

describe perfusion

delivery of oxygenated blood to capillaries/tissues for cellular use

what is ventilation?

breathing

describe inhalation/inspiration 

thorax(chest cavity) expands, so increased lung volume - air flows in - alveoli fill (decreased pressure)

external intercostal muscles push ribs up

diaphragm pushes down

describe expiration/exhalation

thorax recoils, returns to original size (increased pressure in cavity) - CO2 out

internal intercostal muscles / abdominal muscles

describe diffusion in ventilation

oxygen and carbon dioxide flow across the capillary/alveolar membrane

describe what the blood vessels do

maintain pressure and distribute flow to capillaries

how is ventilation effectiveness evaluated? 4

respiratory rate, chest rise, breath sounds, and work of breathing 

describe what gas exchange is

deoxygenated blood from the heart is carried to the lungs through the pulmonary artery

where does gas exchange occur

at the alveolar-capillary membrane

describe what the hemoglobin molecule in RBCs do

it drops off carbon dioxide for exhalation and picks up oxygen during inhalation

how does oxygenated blood return to the heart?

from the lungs by the pulmonary veins 

describe conductivity

generates an impulse

describe excitability

response to the impulse

describe the pathway in little detail of the impulse through the heart

SA node

AV node

bundle of his / AV bundle

R/L bundle branches

what does the impulse from the SA node do?

makes the atria contract 

what’s the rate of contraction from the SA node?

60-100 bpm

what does the impulse do when it travels through the AV node?

makes the ventricles contract

if the SA node stops working, what is next in line to generate impulses?

AV node

40-60bpm

what does electrical conduction produce?

the pulse

influences cardiac output

describe cardiac output

the amount of blood ejected form the heart in one minute

what Is the formula for CO

SV x HR

how is stroke volume impacted

after load

preload

describe preload 

the more volume in the ventricles, the more they stretch. the more they stretch, the more forcefully they contract 

describe after load

its the force/resistance that the ventricles need to overcome

describe diastole / cycle

ventricular relaxation

2/3 of cardiac cycle

describe valves during diastole

AV valves are open allowing blood to flow from atria into ventricles. initially blood flows rapidly due to the pressure in the atria

describe what happens at the end of diastole 

the atria contract to push out the last bit of blood 

describe systole

ventricular contraction 1/3 of cardiac cycle

blood has moved from the atria to ventricles, increasing pressure in the ventricles

describe the valves in systole

AV valves close, contributing to S1

the SL valves open and ventricles contract ejecting blood out

when pressure in ventricles fall below that of the aorta, SL close (S2)

what’re the physiological factors that influence oxygenation and perfusion?

age

obesity

activity 

what’re the lifestyle factors that influence oxygenation and perfusion?

smoking

stress

nutrition

substance abuse

describe age in oxygenation/perfusion

as you get older, contractile strength and elasticity of vessels decreases

describe obesity in oxygenation/perfusion

it impairs lung expansion. it increases cardiac workload

describe activity in oxygenation/perfusion

regular activity improves lung capacity and heart efficiency. 

sedentation reduces both 

describe smoking in oxygenation/perfusion

damages lungs and blood vessels, decreases airflow and oxygen transport

describe stress in oxygenation/perfusion

increased HR and vasoconstriction, more oxygen demand 

describe nutrition in oxygenation/perfusion

saturated fats increase risk for heart disease

describe substance abuse in oxygenation/perfusion

alcohol/drugs depress CNS impairing respiratory and cardiac function

what medications help in oxygenation/perfusion

bronchodilators, antihypertensives, diueretics - they improve oxygen and perfusion

what medications hinder in oxygenation/perfusion

opioids, sedatives, beta-blockers - may decrease respiratory drive or CO

what're the respiratory health history core symptoms?

cough and SOB

what questions would you ask when assessing cough? 6

when did it start? was it gradual or sudden?

is the cough productive or non-productive? describe the sputum (color, odor, amount)

how would you describe the cough?

what makes it better or worse?

associated symptoms?

how does the cough impact ADLs and sleep?

what questions would you ask when assessing SOB? 7

when did it start? what brings it on?

how severe is it and how long does it last?

is it impacted by change of position?

does it occur at a specific time of day or night?

associated symptoms?

how do you manage SOB?

impact on work or ADLs?

what do the respiratory health history contributing and risk factor questions surround?

medical and exposure history 

lifestyle factors 

describe assessing the medical and exposure history?

history of lung disease

recent infections or frequent colds

environmental exposure (dust, chemicals, smoke, occupational hazards, crowded living)

vaccination status (flu, covid, pneumonia)

how to assess lifestyle factors in respiratory health history and contributing factors?

smoking - type, duration, packs/day, attempts to quit

substance use - vaping, weed, alcohol

exercise tolerance - change in activity or fatigue

when doing a physical assessment for respiratory, what do you start with?

inspecting work of breathing including the shape and movement of the thoracic cage.

also look for changes in skin color

what’s the bulk of the respiratory assessment consist of?

auscultation of the anterior and posterior chest 

what is work of breathing?

energy expended to inhale/exhale

what’re the expected findings of WOB?

effortless, rhythmic, and silent

what’re the alternative findings for WOB?

increased rate, decreased depth, mouth breathing, pallor or cyanosis, tripod position, decreased O2 saturation (hypoxia) leading to altered mental status and decreased LOC

describe how the shape of the thorax should be 

narrow apex, broad base 

anterior/posterior diameter should be smaller than the side to side (transverse) diameter

spine should be on the midline

what is barrel chest and who usually gets it?

COPD patients

chest looks like a wine barrel because of air trapping and hyperinflation of the lungs

how should you be observing movement of the chest?

confirm both sides of the chest move symmetrically and that with inspiration the chest rises and during exhalation the chest falls.

what is the specific thing we are listening to when auscultating the thoracic cavity?

sound of air moving through the tracheobronchial tree

how should patient be positioned when auscultating?

sitting is preferred with arms at the side or resting on the lap

describe how to start the auscultation process

clean stethoscope, place diaphragm on pt’s chest, ask them to take a deep breath through the mouth

describe the second part of the auscultation process

auscultate minimum of one respiration at each site, compare bilaterally on the same plane, and always auscultate anterior and posteriorly

what’re the normal things to hear at the tracheal site?

loud, high pitched sounds. inspiratory/expiratory sounds are equal.

what’re the normal things to hear at the brachial site?

loud, high pitched sounds. inspiratory should be shorter than expiratory. hash, hollow, tubular sound

what’re the normal things to hear at the bronchovesticular site?

medium loudness, blowing sound. inspiration and expiration are equal in duration

what’re the normal things to hear at the vesicular site?

low pitched, soft and sound like rustling or hearing wind b/t trees. inspiration is longer than expiration.

where are the ausculatory sites on the anterior chest?

midclavicular line of left and right chest - 2nd intercostal space and 4th intercostal space

midaxillary line - 6th intercostal space

what lobes are heard during 2nd intercostal space?

RUL and LUL - bronchovesicular

what lobes are heard during 4th intercostal space?

RML and LUL - vesicular

what lobes are heard during 6th intercostal space?

RLL and LLL - vesicular 

how should you be proceeding when continuing the auscultation process?

in an S or Snake shape

what’re the auscultatory sites on the posterior chest?

b/t spinous process and clavicle - T2, T5, T7, T9/10

what lobes are heard during T2 ?

RUL and LUL - vesicular

what lobes are heard during T5 ?

bottom of upper lobes and top of lower lobes - vesicular

what lobes are heard during T7 ?

RLL and LLL - vesicular

what lobes are heard during T9/10 ?

bases of RLL and LLL - vesicular 

what’re the adventitious breath sounds? 6

crackles, rhonchi, wheezes, stridor, diminished, or absent

describe crackles

fluid accumulation or inflammation around alveoli, preventing alveoli from fully inflating resulting in discontinuous popping sound

what’re the two types of crackles?

fine - snapping open of alveoli at end of respiration like rubbing hair at end of fingertips

coarse - alveoli re-inflating or air moving through mucous filled trachea/bronchi, like pulling velcro

what could be a condition relating to fine crackle sounds?

heart failure

what could be a condition relating to coarse crackle sounds?

pulmonary edema

what is rhonchi?

fluid, mucous, or growth in larger airway

what does rhonchi sound like?

low-pitched, continuous sound. sometimes clears with coughing, can sound like snoring

what condition can rhonchi be associated with?

pneumonia 

what’re wheezes?

musical, high pitched sound resulting from narrowed airways

what sound is associated with wheezes?

whistling

wheezes during inspiration can be associated with what disease?

asthma

wheezes during expiration can be associated with what disease?

COPD

what is stridor?

high pitched sound caused by possibly life-threatening narrowing of the upper airways

what does stridor sound like

Crowing

what disease process is associated with stridor?

a foreign body or croup

what is diminished breath sounds?

result due to diminished airflow to the lungs. 

when can absent breath sounds be heard?

when a lobe is removed

if there is no explanation for absent breath sounds, what could’ve happened?

collapsed lobe/lung

what diagnostic tests can be used to aid in the diagnosis of cardiopulmonary conditions? 5

chest x ray

CT scan

MRI

arterial blood gases - ABG

Pulmonary Function tests - PFTs

how does an MRI work

imaging that uses radio waves and a powerful magnet to make a series of digital pictures 

what is ABGs?

blood test taken from an artery to measure levels of oxygen and CO2 in the blood

what’re PFTs

evaluate the lung volume, capacity, and rates of flow and gas exchange to determine how well the lungs are working