200809_dyspnea - respirology aspects

8/12/2019 200809_Dyspnea - Respirology Aspects

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Respiratory aspects of

dyspnea


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Dyspnea -1 The sensation of abnormal or uncomfortable

breathing in the context of what is normal for aperson according to his/her level of fitness andexertional threshold for breathless

Am Fam Phys, Evaluation of Dyspnea, 1998

Other terminologies: Shortness of breath

Breathlessness

Difficult breathing

Breathing difficulties

Breathing discomfort

Chest tightness

Breath stops

Air hunger

Labored breathing

Troubled breathing

Getting winded

Constriction

Uncomfortable breathing

Unusual awareness of breathing

Increased breathing effort

Increased muscular effort to breath

The need to breath more


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symptom(subjective) VS sign (objective)

symptom: sensory experience (sensation),

that only could be feel and judge by thepatient psychologic disturbances

sign: respiratory distress, patient breath with

difficulties, involvement of additionalrespiratory muscle physiologic disturbances

Dyspnea -2


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Dyspnea

an abnormal(pathophysiologic)

condition

breathing

phenomenonrespiratory

physiology

to know itbetter


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Breathing respirationBreathing: taking air into the lungs and

send it out againOxford Dictionary

Respiration: the exchange of O2& CO2between the atmosphere and the cells of thebody; includes ventilation(inhalation &

exhalation), the diffusionof oxygen in thealveoli, & the transportof O2& CO2and theuseof them by the cells

Dorlands Medical Dictionary


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Breathing phenomenonunconscious acthealthy persons,

especially children generally unaware

automatic

conscious actwe can control our

own breath limited


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availability of arterial blood(O2, CO2), every timefor the

tissue of the whole body

vital, crucial, can not bepostponed

Respiratory physiology

teamwork of 2 main systems :respiratory & cardiovascular


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Respiration

the primary function is to obtain O2for useby the bodys cells and to eliminate CO2thecells produce

involves the sum of processes thataccomplishmovement of O2 from theatmosphere to the tissue to support cellularmetabolism and removal of CO2 the cellsproduce to the atmosphere

the respiratory system does not participatein all steps in respiration

Sherwood L, The Respiratory System, 2004


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1. Ventilationor gas exchange

between atmosphere and alveoli

2. Diffusionof O2& CO2

between alveoli and the blood

3. Circulation(transport)of O2&

CO2between the lungs and the

tissue

4. Exchange of O2 & CO2

between the blood and the tissues


Steps of Respiration - 1


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producer

Diffusionof O2& CO2between alveoli

& the bloodcrucial point

distributor

consumer


Steps of Respiration - 2


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Respiration - 1

The respiratory system only partiallyparticipate in external respiration

Internal respirationIntracellular metabolic processes carried out within the

mitochondria which use O2& produce CO2 during

the derivation of energy from nutrient molecules

External respiration

The entire sequence of events involved in the exchangeof O2& CO2 between the atmosphere (external

environment) and the alveoli of the lungs


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Respiration- 2

respiratorysystem

cardio-vascularsystem

neuromuscularsystem

respiratorycenter organtissuecell

mitochondria

ENVIRONMENTExternal respiration

Internal respiration

CRUCIAL

POINT!

blood


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2000 Lippincott Williams & Wilkins Fudamentals of Nursing 4th Edition

CRUCIAL

POINT!


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respiratorysystem

cardiovascular

system

ventilation

Diffusionof O2& CO2between alveoli& the bloodcrucial point

perfusion


External respiration - 1


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ventilationV

perfusion

Q

A VOLUME of airFLOW in and out therespiratory tract

Diffusionof O2& CO2between alveoli

& the bloodcrucial point

A VOLUME of bloodFLOW through

alveolar capillary


L/mnt

L/mnt


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ventilationV

perfusion

Q

to take place, gas exchange(diffusion) from air to blood

in alveolar capillary bed needan optimal ratio between

VENTILATION & PERFUSION

V/Q = 4/5


VQQ V


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V/Q = 4/5

V/Q 4/5


V/Q matchoptimal diffusion

V/Q mismatch

not optimal diffusion

Clinically DYSPNEA


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Dyspnea

The sensation of abnormal or uncomfortablebreathing in the context of what is normal for aperson according to his/her level of fitness andexertional threshold for breathless

Am Fam Phys, Evaluation of Dyspnea, 1998

unusual awareness of breathing

the need to breath more

whenever the respiratory mechanism cannot with ease functionate the body need

disproportion : demandsupply


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the mechanisms responsible for dyspnea arestill uncleargenerated centrally orperipherally

afferent activation: from many sites pulmonary stretch receptors

rib joint

respiratory muscles, including diaphragm

others: visceral, neural, emotion no specific receptor

Dyspnea mechanism


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respiratory receptors related to cough center

dyspnea receptor chemoreceptor: hypercapnia, hypoxia

mechanoreceptors : upper airways, lungreceptors (pulmonary stretch receptor, irritantreceptor, C fibers

chest wall receptors

Dyspnea receptors


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according to severity

normal activity -- patient can not walk withoutdyspnea

rest vs exercise onset & progressivity

acute, sub acute, chronic

according to etiology

cardiac, pulmonary, mix cardio-pulmonary,non cardio-pulmonary

Dyspnea classification -1


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Acute VS Chronic(sudden onset) (long standing)

acute: often resolves with treatment of theunderlying condition

chronic: usually result in progressive dysfunction,severe disability, and eventual death

Dyspnea classification -2


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V/Q = 4/5

V/Q 4/5

Dyspnea approach - 1

from this crucial pointwe can make a practical approach

to almost all kind of

DYSPNEA

V/Q mismatch

not optimal diffusion

Clinically DYSPNEA

CRUCIALPOINT!


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Dyspnea approach - 2

the result of V/Q mismatch

organ system involved in respirationespecially respiratory systemtry to

overcome the mismatch, by increase theventilation

2 components of ventilation: flow& volume

FLOWdisturbances:dyspnea with

expiratory effortVOLUMEdisturbances: dyspnea with

inspiratory effort


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Obstruction of proximal /

larger airway

Obstruction of distal / smallerairway

Respiratory center disorders

Extra-pulmonary disorders

Lung compliance disorders

Lung parenchyma disorders

FLOW

disorders

VOLUMEdisorders

EXTRA

thorax

INTRAthorax

EXTRA

thorax

INTRA

thorax

Dyspnea approach -3pathophysiology, anatomic, disorders


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rhinitis with nasal obstruction, nasal polypcranio-facial malformation

OSAS (obstructive sleep apnea syndrome)

tonsil-adenoid hypertrophy

laringo-tracheo-malacia

larynx papilloma

diphtheria

croup, epiglottitisthymus hypertrophy

clinical: inspiratory stridor

Extra-thorax FLOW disordersObstruction of proximal / larger airways


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asthma

bronchiolitis

vascular ring

solid foreign body aspiration

lymph node enlargement pressure

clinical: expiratory effort

Intra-thorax FLOW disordersObstruction of distal / smaller airways


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Lung Parenchyma Disorder

pneumonia (infection, aspiration)

atelectasispulmonary edema

near drowning

sepsis

clinical: inspiratory effort

Intra-thorax VOLUME disorders


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anemia

metabolic acidosis

CNS infections: meningitis, encephalitis

encephalopathy (typhoid, DHF, metabolic)

psychologic (anxiety, usually adolescent)

poisoning: salycylate, alcohol

trauma capitisCNS disease sequelae

clinical:deep rapid breathing

Extra-thorax VOLUME disordersRespiratory center disorders


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200809_dyspnea - respirology aspects

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