5 - Respiratory Distress Flashcards
Dyspnea
Subjective feeling - described as “shortness of breath,” “not getting enough air”
Tachypnea
Rapid breathing
Orthopnea
Dyspnea when recumbent
Paroxysmal nocturnal dyspnea
Orthopnea that wakes you up at night
Trepopnea
Dyspnea associated with only one of the several recumbent positions
Trepopnea can occur with:
Unilateral diaphragmatic paralysis
Ball-valve airway obstruction
Surgical pneumonectomy
Platypnea
The opposite of orthopnea - dyspnea in the UPRIGHT position
Weird, right?
Results from the loss of abdominal wall muscular tone
Hyperpnea
Essentially hyperventilation, and is defined as minute ventilation in excess of metabolic demand
Evidence of impending respiratory failure:
Marked tachypnea and tachycardia Stridor Accessory muscle use One-to-two-word sentences Agitation Lethargy AMS
GIVE OXYGEN
An S3 gallop and interstitial edema on CXR strongly suggests ____ _____ as the cause of dyspnea
Heart failure
Which sxs are NOT useful in discriminating between cardiac and pulmonary causes?
Wheezing DOE Orthopnea PND Leg edema
Conversely, the absence of these sxs does not r/o HF
ABG is more sensitive for detecting impaired gas exchange but cannot evaluate:
Work of breathing
Bedside US can identify:
Pleural effusion Pneumo Cardiac tamponade Cardiac functional abnormalities Pulmonary consolidation Intravascular volume status
Txt goals for severe dyspnea
PaO2 > 60 mmHg
And/or
SaO2 (or SpO2) >/= 90%
Txt the underlying d/o
What is hypoxia?
Insufficient delivery of oxygen to the tissues
What is hypoxemia?
Abnormally low arterial oxygen tension (< 60mmHg)
MC cause of hypoxia?
Hypoxemia
Hypercapnia is exclusively caused by:
Alveolar hypoventilation
Hypercapnia
PaCO2 > 45mmHg
Hypercapnia never results from:
Increased CO2 production alone
Many causes include: rapid shallow breathing, small tidal volumes, underventilation of the lung, or reduced respiratory drive
Sxs of hypercapnia depend on:
The absolute value of PaCO2 and its rate of change
Acute elevations in CO2 result in:
Increased ICP
HA
Confusion
Lethargy
If severe: seizures, coma, CV collapse (PaCO2 > 100mmHg)
Chronic hypercapnia?
May actually be well-tolerated (as opposed to acute hypercapnia)
Can you send a hypercapneic patient home?
Generally, they should be admitted
Exceptions being chronic COPD’ers who are baseline hypercapneic AND stable, can probably be discharged
Wheezing
“Musical” adventitious lung sounds produced by airflow through the central and distal airways
Prolonged duration (typically > 80 milliseconds)
Rhonchi
Lower frequency, usually secretions - able to clear
Crackles or rales
Short duration, suggests air popping through fluid
Wheezing is usually associated with:
Lower airway dz such as asthma, COPD, muscular spasm, inflammation
Upper airway obstruction causes:
Stridor - loudest during inspiration (as opposed to wheezing, which is typically louder during expiration)
Cyanosis
Bluish hue of skin and mucous membranes 2/2 an increased amount of deoxyhemoglobin
Is cyanosis a sensitive indicator of the state of arterial oxygenation?
Nope
It’s determined by the amount of reduced Hb in the blood, NOT the amount of oxygenated HB
Central cyanosis results from
Inadequate pulmonary oxygen exchange
Peripheral cyanosis results from
Vasoconstriction or diminished peripheral blood flow
Causes of central cyanosis:
High altitude
Hypoventilation (cyanosis common in opiate OD)
V/P mismatch (as in APE)
Right-to-left shunt
Causes of peripheral cyanosis
Reduced cardiac output
Cold extremities
Maldistribution of blood flow: distributive shock
Arterial or venous obstruction
Hgb causes of cyanosis?
Methemoglobinemia (hereditary or acquired)
Sulfhemoglobinemia (acquired)
Carboxyhemoglobinemia
Sensitive sites for assessing central cyanosis?
Tongue and buccal mucosa
What is pseudocyanosis?
A bluish or slate-gray skin discoloration due to drugs (chlorpromazine, minocycline, amiodarone, nicorandil) or heavy metals (gold, silver)
Lips/mucus membranes are NORMAL
Discoloration doesn’t blanch with pressure
The discoloration tends to be more intense in sun-exposed areas
What’s up with methemoglobinemia?
In methemoglobinemia, pulse oximetry will read 80% to 85% regardless
of the oxygen level, thereby often overestimating the true oxygen saturation (it may be lower, but pulse oximetry will not read lower)
What’s up with carboxyhemoglobinemia?
The pulse ox reads carboxyhemoglobin as oxyhemoglobin, reporting a higher percentage for O2 sat (think CO poisoning - in a pt with CO poisoning, a standard pulse oximeter is useless)
In central cyanosis, oxygen from ABG will be:
Low
In peripheral cyanosis, oxygen from ABG will be:
Normal
If you give oxygen to your centrally cyanotic patient and they don’t improve, suggests:
Impaired circulation (shock)
Abnormal Hb
Or
Pseudocynanosis
Asthma
Its a breath taking experience
