The Airway, Respiration, and Ventilation*
* from EMT Exam For Dummies by Art Heish
Take a deep breath and hold it for as long as you can, until it’s so uncomfortable that it feels like your lungs will burst. When you finally explode and draw in that first panicky breath, let that feeling serve as a reminder of how important your respiratory system is. If it doesn’t function well, life literally comes to a standstill.
The national EMT exam makes the importance of this fact abundantly clear in the number and
complexity of questions it dedicates to this area. Having the ability to apply your knowledge of the
airway, ventilation, and oxygenation to situations quickly, accurately, and confidently is critical.
In this chapter, you get the basics on the respiratory system, discover when to oxygenate and ventilate, and figure out how to handle a variety of airway and breathing problems.
Getting an Overview of the Respiratory System
In a sense, the respiratory system serves a very simple purpose: to bring oxygen in and get carbon
dioxide out. However, the task is much more complex than that and requires a sophisticated set of
structures:
The upper airway consists of the nares (nostrils), mouth, nasopharynx, pharynx,
and larynx. Combined, they work to not only channel air in and out of the body but to warm,
humidify, and filter it as well.
*
the second picture is less cluttered
The lower airway begins at about the level of the vocal cords and includes the
trachea, mainstem bronchi, and bronchioles, terminating in the alveoli. The bronchi, bronchioles,
and alveoli comprise the lungs. The main function of the lower airway is to produce efficient gas
exchange between the alveoli and capillaries surrounding each alveolus
. Blood passing through the capillaries absorbs the oxygen onto red blood cells, and then circulates oxygen to the body’s cells. At the same time, carbon dioxide is released into the alveolus, which is then exhaled out of the body.
You need oxygen to produce adenosine triphosphate (ATP), the energy block used by the body, and you need to regulate carbon dioxide so just enough is available to the body and the rest is released to the atmosphere. This process takes place in the alveoli, where the cell walls are thin enough to allow
gases to diffuse freely from areas of high concentration to areas of low concentration. So, oxygen
diffuses from the alveoli to the capillaries (into the blood), and carbon dioxide diffuses from the
capillaries into the alveoli (out of the blood).
Of course, the concentration of gases would equalize quickly if the gases just stayed in the alveoli.
Breathing, or ventilation, is the mechanical effort the body makes to move gases into and out of the
lungs. Ventilation occurs with the use of the diaphragm and intercostal muscles
Inspiratory phase: When these muscles contract, the chest cavity increases in size as the
diaphragm moves downward and the ribs are pulled outward by the intercostal muscles. This
produces a slight negative pressure inside the cavity, causing the lungs to expand and drawing air
in. This is the inspiratory phase of ventilation.
Expiratory phase: During the expiratory phase, the reverse occurs. The diaphragm relaxes and
moves upward, and the intercostal muscles relax as the chest returns to its resting position. The
chest cavity shrinks, creating a positive pressure on the lungs. They return to their smaller resting
state, pushing air out of the alveoli and back through the lower and upper airways into the
atmosphere.
The inspiratory and expiratory phases of ventilation.
Under normal resting conditions, this cycle of inspiration and exhalation occurs about 12 to 20 times a
minute, every minute of your life. Chemoreceptors, found primarily in the brainstem, detect levels of
carbon dioxide and oxygen. They send signals to the brain, which, in turn, trigger an increase or
decrease in the work of breathing.
You might think oxygen levels in the body would be the primary driver for respiratory control. But
carbon dioxide (CO2) is the real mover and shaker. That’s because CO2 is used to help create
conditions in the body’s fluids that are best suited for various life functions. So, in a healthy person,
the body depends on detecting a rise in CO2 more than it depends on a drop in oxygen as a reason to
breathe.
Patients who retain CO2 all the time, such as those with chronic obstructive pulmonary disease
(COPD), lose their ability to sense that gas. They end up depending upon hypoxic drive, using
oxygen levels to regulate their breathing.
A 30-year-old male is hyperventilating after receiving very emotional news. His breaths are
fast and deep. Which of the following statements is most accurate in this situation?
(A) Inhaling too much oxygen will cause breathing to slow, allowing oxygen levels to fall to normal
levels.
(B) Inhaling too much oxygen will cause breathing to speed up.
(C) Exhaling too much carbon dioxide will cause breathing to slow, allowing carbon dioxide levels
to rise to normal levels.
(D) Exhaling too much carbon dioxide will cause breathing to speed up.
The correct answer is Choice (C). Assuming everything else is normal, as carbon dioxide levels fall
within the bloodstream, the brain will signal the respiratory system to slow down, allowing it to retain
carbon dioxide and build it back to normal levels.
Choice (A) may be true, but only if the patient has
COPD and depends upon oxygen levels to control breathing.
Neither Choice (B) nor (D) is true.
Knowing the Airway and Breathing Issues to
Look for When You Assess Patients As an EMT, you can’t assume anything about your patient’s condition, even when he appears “normal” at first glance. In your primary assessment, take a few seconds to consciously evaluate how someone is actually breathing. You can start by asking patients how they are feeling; watch and listen to how they respond.
Understanding when breathing is (and isn’t) normal
Ironically, normal breathing is hard to see. That’s because your respiratory system is very effective at
its job. There’s so much surface area in the alveoli that gas exchange is very easy. Therefore, the body
needs to exert very little energy to make gases move between the alveoli and capillaries. If everything
about the respiratory system is working well, the patient will likely be able to speak in full sentences,
spending little energy in the process.
It also takes very little to get the respiratory system to work harder. Suddenly being frightened causes
you to breathe a little faster as your body prepares a “flight or fight” response.
Difficulty breathing begins with an increase in rate (tachypnea). The patient may breathe deeper
(hyperpnea). If the condition doesn’t improve, accessory muscles, such as those in the shoulders and
neck, kick in to maximize the chest cavity on inspiration.
If your patient is experiencing a mild level of respiratory distress, you may notice that he has difficulty completing a long sentence, needing to stop midway to take a breath. Or, he may speak more quickly than normal to try to complete a sentence before he needs to take another breath.
In early stages of distress, the patient may want to only sit up; as the condition worsens, the patient may assume a tripod position, holding his upper body up by putting his hands on his knees and straightening his elbows. In really bad situations, the patient may be forced to stand up in order for the diaphragm to contract and push deep into the abdominal cavity.
Deciding when to oxygenate
EMTs used to give oxygen to everyone, regardless of what the complaint was. Chest pain? Give
oxygen. Toe pain? Yep, give that gas too! After all, what harm could oxygen do, right? Medical experts have since discovered that inhaling more oxygen than necessary can be harmful for certain conditions, and it isn’t helpful in situations where it isn’t necessary.
Translated, this means that you need to assess the patient for his ability to absorb oxygen and
use it. You do this using your powers of observation coupled with a pulse oximeter. If the patient
appears to be ventilating adequately (having a good tidal volume and rate, without the use of
accessory muscles), check for oxygen saturation levels with your oximeter.
Ideally, the saturation level should be between 94 and 99 percent.
What does this mean? If the patient is breathing normally, and his oxygen saturation level is greater
than 94 percent, you don’t need to administer oxygen. If the saturation level is lower or normal but the
patient has mild respiratory difficulty, a nasal canula with oxygen flowing between 2 and 6 liters per
minute (LPM) is probably fine. If the patient is working hard to breathe, a nonrebreather mask at 12–
15 LPM may be needed. Carefully monitor saturation readings and the patient’s level of distress. If
things don’t improve, you may need to provide manual ventilation (see the next section).
Oxygen is carried on hemoglobin proteins located within the red blood cells (RBCs). Each
hemoglobin can carry up to four molecules of oxygen. As hemoglobin picks up oxygen, the color
of the RBC changes from a dusky, dark red to a brighter shade. A pulse oximeter can detect these
shades of red and calculate the percentage of red blood cells that are carrying oxygen in their
hemoglobin. Normal amounts are around 94 percent or higher. Once oxygen saturation drops to
about 92 percent, the change in subsequent saturation levels can be quick, dropping to 85 percent
or even lower within a few minutes.
A 42-year-old male is complaining of abdominal pain and cramping after eating a fried
chicken dinner. He is alert, with pink, warm, diaphoretic skin. His vital signs include a pulse rate
of 92, a blood pressure of 142/90 mm Hg, and a respiratory rate of 18 breaths per minute. His
oxygen saturation level is 96 percent. What should you do next?
(A) Administer oxygen at 4 LPM with a nasal cannula.
(B) Administer oxygen at 15 LPM with a nonrebreather mask.
(C) Perform a secondary assessment.
(D) Begin immediate transport.
The correct answer is Choice (C). Based on the patient’s chief complaint, relatively normal vital
signs, and lack of evidence of respiratory distress, oxygen, Choices (A) and (B), is not indicated.
There is also no indication of an emergent condition that requires immediate transport, Choice (D).
Recognizing when to ventilate
To know when to ventilate is to know when the patient crosses the line between respiratory distress
and respiratory failure:
Respiratory distress: In respiratory distress, the patient is compensating for a potential hypoxia
problem by breathing faster, deeper, and/or harder. By doing so, the patient’s mental status remains
good, as do his oxygen saturation levels (see the preceding section).
Respiratory failure: If the compensatory mechanisms don’t maintain adequate oxygen or carbon
dioxide levels, the patient’s well-being begins to falter. Mental status changes from alert to
confused to unconsciousness as the brain runs out of oxygen or fills with carbon dioxide. Oxygen
saturation levels drop below normal. The patient’s drive to breathe weakens, causing ventilations
to become inadequate. This state, in turn, makes oxygen levels fall even further, creating a vicious
cycle. Breathing slows and becomes even more shallow. If left untreated, respiratory failure will
deteriorate to respiratory arrest, followed quickly by cardiac arrest.
Recognizing early signs of respiratory failure is key. If the patient looks tired, is having
difficulty remaining alert, or his skin becomes very pale or cyanotic, cool, and clammy, it’s time
to break out your bag-valve mask (BVM) and deliver manual ventilations.
An early sign of hypoxia is anxiety. The brain is so sensitive to oxygen levels that minor
changes trigger it to start sending out alerts. If your patient looks or feels anxious, definitely
provide reassurance, but also consider whether you’re seeing the first signs of a more serious
problem.
A 70-year-old female is complaining of shortness of breath that began shortly after a nap. She
is alert and appears anxious. She is breathing 30 times per minute and says her fingers and face
feel numb. You should (A) assist with her breathing with a bag-valve mask and oxygen.
(B) provide supplemental oxygen at 4 LPM using a nasal cannula.
(C) have her breathe into a face mask without oxygen attached.
(D) tell her to control her anxiety and that will help with her breathing.
The correct answer is Choice (B). Even though she is breathing quickly, she is alert and
communicating with you, which indicates she is getting enough oxygen to her brain. Therefore, she’s
not in respiratory failure and doesn’t require artificial ventilation, Choice (A). However, she may be
in true respiratory distress, trying to maintain oxygen levels. The last thing you want to do is to have
her rebreathe her own CO2 and reduce the amount of available oxygen, Choice (C). While she may be
experiencing anxiety, she may be hyperventilating for another reason, such as having a pulmonary
embolus. Choice (D), although tempting, isn’t likely to control her breathing.
Taking Action on Potential Airway and Breathing
Problems
Many conditions can affect the airway and breathing, causing someone to become short of breath. And,
because the respiratory system reacts to events happening inside the body, many nonrespiratory
conditions can cause difficulty breathing as well. I don’t cover them all in the following sections, but a
good rule of thumb is to always think beyond the breathing tube when a patient is having trouble
breathing yet her respiratory system seems okay.
Upper airway conditions
Given that the airway is the only way for air to enter and exit the body, anything that partially or
completely blocks it is troublesome, to say the least. Table 9-1 lists common conditions you should be
familiar with, their signs and symptoms, and treatment options for each.
Table 9-1 Conditions Affecting the Upper Airway
Problem Signs and Symptoms Action Steps
Anaphylaxis
causing
major
swelling of
the upper
airway
Exposure to an allergen such as a bee sting or peanuts;
drooling; reddened oropharynx; muffled or whispered voice;
possible hypotension.
Assist the patient in using an epinephrine injector; administer
supplemental oxygen; ventilate as necessary to maintain
oxygen saturation.
Croup
Usually occurs in young children; fever; stridor, raspy cough;
sometimes relieved with a quick change in air temperature
and/or humidity.
Have parent assist with positioning the child comfortably;
administer blow-by, humidified oxygen.
Epiglottitis High fever; drooling; reddened oropharynx; muffled or
whispered voice; unable to lie down.
Don’t stick anything into the mouth! Help the patient into a
comfortable position; administer blow-by oxygen.
Foreign body
obstruction
Full obstruction: Air is unable to pass by the obstruction. No
noise or breathing sounds from airway; skin turns pale to
cyanotic; universal choking sign.
Partial obstruction: Air is able to move past the obstruction.
Patient may be coughing; audible stridor.
Conscious patient: Administer abdominal thrusts (child and
adult) or chest thrusts/back blows (infant). If airway is partially
obstructed, encourage patient to cough; keep suction
available and prepare to act if airway becomes fully
obstructed.
Unconscious patient: Administer chest compressions (CPR).
Pertussis
Prolonged coughing spells; “whoop” sound when patient
takes a deep breath after coughing; more prevalent in
children; dark, thick mucous production; 1–2 week history of
mild fever and coughing that worsens in duration and
discomfort.
Wear personal protective equipment (PPE), including a HEPA
mask; administer supplemental, humidified oxygen.
Tongue
blocking the
airway
Patient has altered mental status or is unresponsive,
allowing tongue to relax and block the airway. Snoring
sounds may be heard. In severe situations, breathing may
become irregular or absent.
Perform head-tilt, chin-lift technique; if neck trauma
suspected, utilize a modified jaw-thrust maneuver. Insert
oropharyngeal or nasopharyngeal airway to help control the
tongue.
A 65-year-old male fell off a stepladder while attempting to replace a light bulb. You find him
unresponsive to painful stimulus. He has a large hematoma to his left temple. He has slow,
irregular, snoring respirations and his skin is pale, cool, and diaphoretic. After taking manual
spine precautions, you should next (A) apply a head-tilt, chin-lift and insert an oropharyngeal
airway.
(B) administer high-flow oxygen with a nonrebreather mask.
(C) apply a modified jaw thrust and insert an oropharyngeal airway.
(D) ventilate with a bag-valve mask with high-flow oxygen.
The right answer is Choice (C). There are indications that a spinal injury may exist (mechanism of
injury, a head injury, and a patient who is unable to communicate). A modified jaw thrust will open the
patient’s airway while minimizing motion to the cervical spine, unlike a head-tilt, chin-lift procedure,
Choice (A). The patient's ventilation status is inadequate for simple supplemental oxygen, Choice (B).
You’ll need to ventilate the patient, Choice (D), but not until after opening the airway.
Lower airway conditions
Table 9-2 lists a variety of common conditions affecting the lower airway structures, causing shortness
of breath.
Table 9-2 Conditions Affecting the Lower Airway
Problem Signs and Symptoms Action Steps
Asthma Episodic respiratory distress; wheezes auscultated during breathing;
may have past medical history; may have prescribed inhalers.
Assist with patient’s prescribed emergency
inhaler if available; administer supplemental
oxygen; ventilate if necessary to maintain oxygen
saturation.
Bronchiolitis;
respiratory
syncytial virus
(RSV)
Presents mostly in children to 2 years of age; gradual onset of fever,
cough, and general weakness.
Wear personal protective equipment (PPE);
administer supplemental, humidified oxygen.
Chronic
obstructive
pulmonary
disease
(COPD)
Chronic shortness of breath that has abruptly become worse; wheezes,
crackles, or rhonchi auscultated during breathing; patient may be thin
with an enlarged chest wall (emphysema) or appear bloated and heavy
with dusky skin (chronic bronchitis); probable past medical history; may
have prescribed inhalers; smoking history.
Assist with patient’s prescribed emergency
inhaler if available; administer supplemental
oxygen; ventilate if necessary to maintain oxygen
saturation.
Cystic fibrosis Genetic condition; chronic illness with acute worsening; heavy mucous
production.
Help patient into a comfortable position; suction;
administer supplemental oxygen; ventilate as
needed to maintain saturation.
Pneumonia
Fever; 1–2 week history of flu or cold symptoms; productive cough with
yellow to green sputum production; may auscultate crackles, rhonchi, or
wheezes in lung fields; may have chest pain that worsens with cough.
Help patient into a comfortable position;
administer supplemental oxygen (consider
humidification).
Pulmonary
edema
Sudden onset; may auscultate crackles or wheezes in lung fields or
sounds may be very diminished as condition worsens; if hypertensive,
may have jugular venous distension; pedal edema; in worse cases,
produces frothy, pink-colored sputum with cough; may have history of
congestive heart failure, hypertension, or myocardial infarction.
If blood pressure (BP) is normal or high, assist
patient in sitting upright with feet dangling for
comfort; administer supplemental oxygen;
ventilate as necessary to maintain saturation.
Consider continuous positive airway pressure
(CPAP).
Pulmonary
embolism
Sudden onset; lung sounds remain clear or may have a localized
wheeze; may have chest pain; may have tender calf in lower leg; recent
history of immobilization such as surgery or a long air flight; oral birth
control user or smoker.
Administer supplemental oxygen; ventilate if
necessary to maintain oxygen saturation. This
condition may mimic psychogenic
hyperventilation; do not use paper bag or withhold
oxygen.
Spontaneous
pneumothorax
Sudden onset; may occur after prolonged coughing or heavy lifting; lung
sounds may be normal, or diminished on one side; may experience
sharp chest pain; may have history of asthma, COPD, or connective
tissue disease.
Help patient into a comfortable position;
administer supplemental oxygen.
A 52-year-old female is in respiratory distress. Her heart rate is 104, and her blood pressure
is 148/82 mm Hg. She is breathing 24 times per minute and her oxygen saturation level is 95
percent. She tells you that she has been experiencing cold-type symptoms for ten days; during the
last two days she has been producing yellow sputum when she coughs. She has a history of
asthma, angina, and hypertension, and takes medication for both conditions, including a rescue
inhaler and nitroglycerin tablets. You note no accessory muscle use when she breathes. You
auscultate her lungs and hear rhonchi. You should (A) assist with administering her rescue
inhaler.
(B) administer oxygen at 4 LPM via nasal cannula.
(C) administer oxygen at 15 LPM via a nonrebreather mask.
(D) assist with administering a nitroglycerin tablet.
The correct answer is Choice (B). The information provided in the question points to pneumonia as the
underlying cause of the patient’s respiratory distress. There are no signs of an acute asthma attack or
angina, so assisting with her medications, Choices (A) and (D), isn’t indicated. Her level of
respiratory distress is not severe, as indicated by a reasonable oxygen saturation level and lack of
accessory muscle use. High-flow oxygen, Choice (C), isn’t indicated.
Nonrespiratory conditions
When other, nonrespiratory conditions arise that affect oxygen and/or carbon dioxide levels in the
body, the respiratory system attempts to compensate by working harder. Some of the more common
ones are listed in Table 9-3.
Table 9-3 Nonrespiratory Conditions that May Affect Breathing
Problem Signs and Symptoms Action Steps
Environmental/industrial
exposure to toxic gas
or chemicals
Hazardous scene; may involve multiple victims; coughing;
nausea, vomiting; may have secretions from eyes, nose, or
mouth; lung sounds may be clear or may contain wheezes or
crackles; headache, blurred vision (especially with carbon
monoxide poisoning).
Operate in cold zone; decontaminate if
necessary; remove patient to fresh air; administer
supplemental oxygen; ventilate if necessary to
maintain saturation.
Metabolic acidosis
Condition resulting from excessive hydrogen ion (H+) buildup in
the blood causing high acid levels. The body attempts to shift
the acid levels back to normal by buffering H+ with bicarbonate,
causing CO2 to form. The patient breathes faster and deeper
(Kussmaul's respirations) to remove the extra CO2.
None directly. Provide supplemental oxygen if
indicated. Don’t attempt a procedure that would
cause the patient to retain more CO2, such as
breathing into a paper bag or an oxygen mask
without oxygen being administered through it.
Myocardial infarction May have chest discomfort; normal lung sounds; may be
elderly, female, or diabetic.
Help patient into a comfortable position;
administer supplemental oxygen; ventilate if
necessary to maintain saturation.
Opioid (narcotic)
overdose
Opioids like heroin and morphine cause altered mental status
and suppress the respiratory drive, causing slow, shallow
respirations that deteriorate to respiratory arrest.
Insert OPA or NPA to control airway; perform
head-tilt, chin-lift maneuver; begin ventilations
with bag-valve mask and oxygen.
Psychogenic
hyperventilation
Psychological trigger; normal lung sounds; carpopedal spasms;
numbness in face, hands, or feet.
Help patient into a comfortable position; coach to
control breathing; administer supplemental
oxygen. Do not use paper bags or other home
remedies.
By no means is this an exhaustive list; just be sure to keep your mind open to the possibility
that someone who is having trouble breathing is experiencing a problem not related to the
respiratory system.
An alert, 80-year-old male complains of sudden shortness of breath. His skin is pale, cool,
and moist. He tells you he began feeling this way about an hour ago, while he was sitting and
reading a book. His vital signs include a respiratory rate of 16 breaths per minute, his pulse is 90
and regular, and his blood pressure is 160/96 mm Hg. He has a history of high blood pressure and
diabetes, and is allergic to bees. Lung sounds are clear bilaterally. His oxygen saturation level is
97 percent. You should (A) administer high-flow oxygen via a nonrebreather mask.
(B) place the patient in position of comfort.
(C) encourage him to drink some orange juice with sugar.
(D) assist with an epinephrine autoinjector, if he has one.
The right answer is Choice (B). Although the patient’s presentation is vague, his age and a sudden
onset of feeling short of breath point to a possible myocardial infarction. Keeping the patient calm and
comfortable is key to preserving myocardial tissue. Although the patient feels like he is short of breath,
there’s little evidence of respiratory distress. High-flow oxygen, Choice (A), is not warranted. He is
alert, suggesting hypoglycemia, which Choice (C) alludes to, is not the culprit. There is no evidence of
a severe allergic reaction as Choice (D) implie
^
* from EMT Exam For Dummies by Art Heish
Take a deep breath and hold it for as long as you can, until it’s so uncomfortable that it feels like your lungs will burst. When you finally explode and draw in that first panicky breath, let that feeling serve as a reminder of how important your respiratory system is. If it doesn’t function well, life literally comes to a standstill.
The national EMT exam makes the importance of this fact abundantly clear in the number and
complexity of questions it dedicates to this area. Having the ability to apply your knowledge of the
airway, ventilation, and oxygenation to situations quickly, accurately, and confidently is critical.
In this chapter, you get the basics on the respiratory system, discover when to oxygenate and ventilate, and figure out how to handle a variety of airway and breathing problems.
Getting an Overview of the Respiratory System
In a sense, the respiratory system serves a very simple purpose: to bring oxygen in and get carbon
dioxide out. However, the task is much more complex than that and requires a sophisticated set of
structures:
The upper airway consists of the nares (nostrils), mouth, nasopharynx, pharynx,
and larynx. Combined, they work to not only channel air in and out of the body but to warm,
humidify, and filter it as well.
The lower airway begins at about the level of the vocal cords and includes the
trachea, mainstem bronchi, and bronchioles, terminating in the alveoli. The bronchi, bronchioles,
and alveoli comprise the lungs. The main function of the lower airway is to produce efficient gas
exchange between the alveoli and capillaries surrounding each alveolus
. Blood passing through the capillaries absorbs the oxygen onto red blood cells, and then circulates oxygen to the body’s cells. At the same time, carbon dioxide is released into the alveolus, which is then exhaled out of the body.
You need oxygen to produce adenosine triphosphate (ATP), the energy block used by the body, and you need to regulate carbon dioxide so just enough is available to the body and the rest is released to the atmosphere. This process takes place in the alveoli, where the cell walls are thin enough to allow
gases to diffuse freely from areas of high concentration to areas of low concentration. So, oxygen
diffuses from the alveoli to the capillaries (into the blood), and carbon dioxide diffuses from the
capillaries into the alveoli (out of the blood).
Of course, the concentration of gases would equalize quickly if the gases just stayed in the alveoli.
Breathing, or ventilation, is the mechanical effort the body makes to move gases into and out of the
lungs. Ventilation occurs with the use of the diaphragm and intercostal muscles
Inspiratory phase: When these muscles contract, the chest cavity increases in size as the
diaphragm moves downward and the ribs are pulled outward by the intercostal muscles. This
produces a slight negative pressure inside the cavity, causing the lungs to expand and drawing air
in. This is the inspiratory phase of ventilation.
Expiratory phase: During the expiratory phase, the reverse occurs. The diaphragm relaxes and
moves upward, and the intercostal muscles relax as the chest returns to its resting position. The
chest cavity shrinks, creating a positive pressure on the lungs. They return to their smaller resting
state, pushing air out of the alveoli and back through the lower and upper airways into the
atmosphere.
Under normal resting conditions, this cycle of inspiration and exhalation occurs about 12 to 20 times a
minute, every minute of your life. Chemoreceptors, found primarily in the brainstem, detect levels of
carbon dioxide and oxygen. They send signals to the brain, which, in turn, trigger an increase or
decrease in the work of breathing.
You might think oxygen levels in the body would be the primary driver for respiratory control. But
carbon dioxide (CO2) is the real mover and shaker. That’s because CO2 is used to help create
conditions in the body’s fluids that are best suited for various life functions. So, in a healthy person,
the body depends on detecting a rise in CO2 more than it depends on a drop in oxygen as a reason to
breathe.
Patients who retain CO2 all the time, such as those with chronic obstructive pulmonary disease
(COPD), lose their ability to sense that gas. They end up depending upon hypoxic drive, using
oxygen levels to regulate their breathing.
A 30-year-old male is hyperventilating after receiving very emotional news. His breaths are
fast and deep. Which of the following statements is most accurate in this situation?
(A) Inhaling too much oxygen will cause breathing to slow, allowing oxygen levels to fall to normal
levels.
(B) Inhaling too much oxygen will cause breathing to speed up.
(C) Exhaling too much carbon dioxide will cause breathing to slow, allowing carbon dioxide levels
to rise to normal levels.
(D) Exhaling too much carbon dioxide will cause breathing to speed up.
The correct answer is Choice (C). Assuming everything else is normal, as carbon dioxide levels fall
within the bloodstream, the brain will signal the respiratory system to slow down, allowing it to retain
carbon dioxide and build it back to normal levels.
Choice (A) may be true, but only if the patient has
COPD and depends upon oxygen levels to control breathing.
Neither Choice (B) nor (D) is true.
Knowing the Airway and Breathing Issues to
Look for When You Assess Patients As an EMT, you can’t assume anything about your patient’s condition, even when he appears “normal” at first glance. In your primary assessment, take a few seconds to consciously evaluate how someone is actually breathing. You can start by asking patients how they are feeling; watch and listen to how they respond.
Understanding when breathing is (and isn’t) normal
Ironically, normal breathing is hard to see. That’s because your respiratory system is very effective at
its job. There’s so much surface area in the alveoli that gas exchange is very easy. Therefore, the body
needs to exert very little energy to make gases move between the alveoli and capillaries. If everything
about the respiratory system is working well, the patient will likely be able to speak in full sentences,
spending little energy in the process.
It also takes very little to get the respiratory system to work harder. Suddenly being frightened causes
you to breathe a little faster as your body prepares a “flight or fight” response.
Difficulty breathing begins with an increase in rate (tachypnea). The patient may breathe deeper
(hyperpnea). If the condition doesn’t improve, accessory muscles, such as those in the shoulders and
neck, kick in to maximize the chest cavity on inspiration.
If your patient is experiencing a mild level of respiratory distress, you may notice that he has difficulty completing a long sentence, needing to stop midway to take a breath. Or, he may speak more quickly than normal to try to complete a sentence before he needs to take another breath.
In early stages of distress, the patient may want to only sit up; as the condition worsens, the patient may assume a tripod position, holding his upper body up by putting his hands on his knees and straightening his elbows. In really bad situations, the patient may be forced to stand up in order for the diaphragm to contract and push deep into the abdominal cavity.
Deciding when to oxygenate
EMTs used to give oxygen to everyone, regardless of what the complaint was. Chest pain? Give
oxygen. Toe pain? Yep, give that gas too! After all, what harm could oxygen do, right? Medical experts have since discovered that inhaling more oxygen than necessary can be harmful for certain conditions, and it isn’t helpful in situations where it isn’t necessary.
Translated, this means that you need to assess the patient for his ability to absorb oxygen and
use it. You do this using your powers of observation coupled with a pulse oximeter. If the patient
appears to be ventilating adequately (having a good tidal volume and rate, without the use of
accessory muscles), check for oxygen saturation levels with your oximeter.
Ideally, the saturation level should be between 94 and 99 percent.
What does this mean? If the patient is breathing normally, and his oxygen saturation level is greater
than 94 percent, you don’t need to administer oxygen. If the saturation level is lower or normal but the
patient has mild respiratory difficulty, a nasal canula with oxygen flowing between 2 and 6 liters per
minute (LPM) is probably fine. If the patient is working hard to breathe, a nonrebreather mask at 12–
15 LPM may be needed. Carefully monitor saturation readings and the patient’s level of distress. If
things don’t improve, you may need to provide manual ventilation (see the next section).
Oxygen is carried on hemoglobin proteins located within the red blood cells (RBCs). Each
hemoglobin can carry up to four molecules of oxygen. As hemoglobin picks up oxygen, the color
of the RBC changes from a dusky, dark red to a brighter shade. A pulse oximeter can detect these
shades of red and calculate the percentage of red blood cells that are carrying oxygen in their
hemoglobin. Normal amounts are around 94 percent or higher. Once oxygen saturation drops to
about 92 percent, the change in subsequent saturation levels can be quick, dropping to 85 percent
or even lower within a few minutes.
A 42-year-old male is complaining of abdominal pain and cramping after eating a fried
chicken dinner. He is alert, with pink, warm, diaphoretic skin. His vital signs include a pulse rate
of 92, a blood pressure of 142/90 mm Hg, and a respiratory rate of 18 breaths per minute. His
oxygen saturation level is 96 percent. What should you do next?
(A) Administer oxygen at 4 LPM with a nasal cannula.
(B) Administer oxygen at 15 LPM with a nonrebreather mask.
(C) Perform a secondary assessment.
(D) Begin immediate transport.
The correct answer is Choice (C). Based on the patient’s chief complaint, relatively normal vital
signs, and lack of evidence of respiratory distress, oxygen, Choices (A) and (B), is not indicated.
There is also no indication of an emergent condition that requires immediate transport, Choice (D).
Recognizing when to ventilate
To know when to ventilate is to know when the patient crosses the line between respiratory distress
and respiratory failure:
Respiratory distress: In respiratory distress, the patient is compensating for a potential hypoxia
problem by breathing faster, deeper, and/or harder. By doing so, the patient’s mental status remains
good, as do his oxygen saturation levels (see the preceding section).
Respiratory failure: If the compensatory mechanisms don’t maintain adequate oxygen or carbon
dioxide levels, the patient’s well-being begins to falter. Mental status changes from alert to
confused to unconsciousness as the brain runs out of oxygen or fills with carbon dioxide. Oxygen
saturation levels drop below normal. The patient’s drive to breathe weakens, causing ventilations
to become inadequate. This state, in turn, makes oxygen levels fall even further, creating a vicious
cycle. Breathing slows and becomes even more shallow. If left untreated, respiratory failure will
deteriorate to respiratory arrest, followed quickly by cardiac arrest.
Recognizing early signs of respiratory failure is key. If the patient looks tired, is having
difficulty remaining alert, or his skin becomes very pale or cyanotic, cool, and clammy, it’s time
to break out your bag-valve mask (BVM) and deliver manual ventilations.
An early sign of hypoxia is anxiety. The brain is so sensitive to oxygen levels that minor
changes trigger it to start sending out alerts. If your patient looks or feels anxious, definitely
provide reassurance, but also consider whether you’re seeing the first signs of a more serious
problem.
A 70-year-old female is complaining of shortness of breath that began shortly after a nap. She
is alert and appears anxious. She is breathing 30 times per minute and says her fingers and face
feel numb. You should (A) assist with her breathing with a bag-valve mask and oxygen.
(B) provide supplemental oxygen at 4 LPM using a nasal cannula.
(C) have her breathe into a face mask without oxygen attached.
(D) tell her to control her anxiety and that will help with her breathing.
The correct answer is Choice (B). Even though she is breathing quickly, she is alert and
communicating with you, which indicates she is getting enough oxygen to her brain. Therefore, she’s
not in respiratory failure and doesn’t require artificial ventilation, Choice (A). However, she may be
in true respiratory distress, trying to maintain oxygen levels. The last thing you want to do is to have
her rebreathe her own CO2 and reduce the amount of available oxygen, Choice (C). While she may be
experiencing anxiety, she may be hyperventilating for another reason, such as having a pulmonary
embolus. Choice (D), although tempting, isn’t likely to control her breathing.
Taking Action on Potential Airway and Breathing
Problems
Many conditions can affect the airway and breathing, causing someone to become short of breath. And,
because the respiratory system reacts to events happening inside the body, many nonrespiratory
conditions can cause difficulty breathing as well. I don’t cover them all in the following sections, but a
good rule of thumb is to always think beyond the breathing tube when a patient is having trouble
breathing yet her respiratory system seems okay.
Upper airway conditions
Given that the airway is the only way for air to enter and exit the body, anything that partially or
completely blocks it is troublesome, to say the least. Table 9-1 lists common conditions you should be
familiar with, their signs and symptoms, and treatment options for each.
Table 9-1 Conditions Affecting the Upper Airway
Problem Signs and Symptoms Action Steps
Anaphylaxis
causing
major
swelling of
the upper
airway
Exposure to an allergen such as a bee sting or peanuts;
drooling; reddened oropharynx; muffled or whispered voice;
possible hypotension.
Assist the patient in using an epinephrine injector; administer
supplemental oxygen; ventilate as necessary to maintain
oxygen saturation.
Croup
Usually occurs in young children; fever; stridor, raspy cough;
sometimes relieved with a quick change in air temperature
and/or humidity.
Have parent assist with positioning the child comfortably;
administer blow-by, humidified oxygen.
Epiglottitis High fever; drooling; reddened oropharynx; muffled or
whispered voice; unable to lie down.
Don’t stick anything into the mouth! Help the patient into a
comfortable position; administer blow-by oxygen.
Foreign body
obstruction
Full obstruction: Air is unable to pass by the obstruction. No
noise or breathing sounds from airway; skin turns pale to
cyanotic; universal choking sign.
Partial obstruction: Air is able to move past the obstruction.
Patient may be coughing; audible stridor.
Conscious patient: Administer abdominal thrusts (child and
adult) or chest thrusts/back blows (infant). If airway is partially
obstructed, encourage patient to cough; keep suction
available and prepare to act if airway becomes fully
obstructed.
Unconscious patient: Administer chest compressions (CPR).
Pertussis
Prolonged coughing spells; “whoop” sound when patient
takes a deep breath after coughing; more prevalent in
children; dark, thick mucous production; 1–2 week history of
mild fever and coughing that worsens in duration and
discomfort.
Wear personal protective equipment (PPE), including a HEPA
mask; administer supplemental, humidified oxygen.
Tongue
blocking the
airway
Patient has altered mental status or is unresponsive,
allowing tongue to relax and block the airway. Snoring
sounds may be heard. In severe situations, breathing may
become irregular or absent.
Perform head-tilt, chin-lift technique; if neck trauma
suspected, utilize a modified jaw-thrust maneuver. Insert
oropharyngeal or nasopharyngeal airway to help control the
tongue.
A 65-year-old male fell off a stepladder while attempting to replace a light bulb. You find him
unresponsive to painful stimulus. He has a large hematoma to his left temple. He has slow,
irregular, snoring respirations and his skin is pale, cool, and diaphoretic. After taking manual
spine precautions, you should next (A) apply a head-tilt, chin-lift and insert an oropharyngeal
airway.
(B) administer high-flow oxygen with a nonrebreather mask.
(C) apply a modified jaw thrust and insert an oropharyngeal airway.
(D) ventilate with a bag-valve mask with high-flow oxygen.
The right answer is Choice (C). There are indications that a spinal injury may exist (mechanism of
injury, a head injury, and a patient who is unable to communicate). A modified jaw thrust will open the
patient’s airway while minimizing motion to the cervical spine, unlike a head-tilt, chin-lift procedure,
Choice (A). The patient's ventilation status is inadequate for simple supplemental oxygen, Choice (B).
You’ll need to ventilate the patient, Choice (D), but not until after opening the airway.
Lower airway conditions
Table 9-2 lists a variety of common conditions affecting the lower airway structures, causing shortness
of breath.
Table 9-2 Conditions Affecting the Lower Airway
Problem Signs and Symptoms Action Steps
Asthma Episodic respiratory distress; wheezes auscultated during breathing;
may have past medical history; may have prescribed inhalers.
Assist with patient’s prescribed emergency
inhaler if available; administer supplemental
oxygen; ventilate if necessary to maintain oxygen
saturation.
Bronchiolitis;
respiratory
syncytial virus
(RSV)
Presents mostly in children to 2 years of age; gradual onset of fever,
cough, and general weakness.
Wear personal protective equipment (PPE);
administer supplemental, humidified oxygen.
Chronic
obstructive
pulmonary
disease
(COPD)
Chronic shortness of breath that has abruptly become worse; wheezes,
crackles, or rhonchi auscultated during breathing; patient may be thin
with an enlarged chest wall (emphysema) or appear bloated and heavy
with dusky skin (chronic bronchitis); probable past medical history; may
have prescribed inhalers; smoking history.
Assist with patient’s prescribed emergency
inhaler if available; administer supplemental
oxygen; ventilate if necessary to maintain oxygen
saturation.
Cystic fibrosis Genetic condition; chronic illness with acute worsening; heavy mucous
production.
Help patient into a comfortable position; suction;
administer supplemental oxygen; ventilate as
needed to maintain saturation.
Pneumonia
Fever; 1–2 week history of flu or cold symptoms; productive cough with
yellow to green sputum production; may auscultate crackles, rhonchi, or
wheezes in lung fields; may have chest pain that worsens with cough.
Help patient into a comfortable position;
administer supplemental oxygen (consider
humidification).
Pulmonary
edema
Sudden onset; may auscultate crackles or wheezes in lung fields or
sounds may be very diminished as condition worsens; if hypertensive,
may have jugular venous distension; pedal edema; in worse cases,
produces frothy, pink-colored sputum with cough; may have history of
congestive heart failure, hypertension, or myocardial infarction.
If blood pressure (BP) is normal or high, assist
patient in sitting upright with feet dangling for
comfort; administer supplemental oxygen;
ventilate as necessary to maintain saturation.
Consider continuous positive airway pressure
(CPAP).
Pulmonary
embolism
Sudden onset; lung sounds remain clear or may have a localized
wheeze; may have chest pain; may have tender calf in lower leg; recent
history of immobilization such as surgery or a long air flight; oral birth
control user or smoker.
Administer supplemental oxygen; ventilate if
necessary to maintain oxygen saturation. This
condition may mimic psychogenic
hyperventilation; do not use paper bag or withhold
oxygen.
Spontaneous
pneumothorax
Sudden onset; may occur after prolonged coughing or heavy lifting; lung
sounds may be normal, or diminished on one side; may experience
sharp chest pain; may have history of asthma, COPD, or connective
tissue disease.
Help patient into a comfortable position;
administer supplemental oxygen.
A 52-year-old female is in respiratory distress. Her heart rate is 104, and her blood pressure
is 148/82 mm Hg. She is breathing 24 times per minute and her oxygen saturation level is 95
percent. She tells you that she has been experiencing cold-type symptoms for ten days; during the
last two days she has been producing yellow sputum when she coughs. She has a history of
asthma, angina, and hypertension, and takes medication for both conditions, including a rescue
inhaler and nitroglycerin tablets. You note no accessory muscle use when she breathes. You
auscultate her lungs and hear rhonchi. You should (A) assist with administering her rescue
inhaler.
(B) administer oxygen at 4 LPM via nasal cannula.
(C) administer oxygen at 15 LPM via a nonrebreather mask.
(D) assist with administering a nitroglycerin tablet.
The correct answer is Choice (B). The information provided in the question points to pneumonia as the
underlying cause of the patient’s respiratory distress. There are no signs of an acute asthma attack or
angina, so assisting with her medications, Choices (A) and (D), isn’t indicated. Her level of
respiratory distress is not severe, as indicated by a reasonable oxygen saturation level and lack of
accessory muscle use. High-flow oxygen, Choice (C), isn’t indicated.
Nonrespiratory conditions
When other, nonrespiratory conditions arise that affect oxygen and/or carbon dioxide levels in the
body, the respiratory system attempts to compensate by working harder. Some of the more common
ones are listed in Table 9-3.
Table 9-3 Nonrespiratory Conditions that May Affect Breathing
Problem Signs and Symptoms Action Steps
Environmental/industrial
exposure to toxic gas
or chemicals
Hazardous scene; may involve multiple victims; coughing;
nausea, vomiting; may have secretions from eyes, nose, or
mouth; lung sounds may be clear or may contain wheezes or
crackles; headache, blurred vision (especially with carbon
monoxide poisoning).
Operate in cold zone; decontaminate if
necessary; remove patient to fresh air; administer
supplemental oxygen; ventilate if necessary to
maintain saturation.
Metabolic acidosis
Condition resulting from excessive hydrogen ion (H+) buildup in
the blood causing high acid levels. The body attempts to shift
the acid levels back to normal by buffering H+ with bicarbonate,
causing CO2 to form. The patient breathes faster and deeper
(Kussmaul's respirations) to remove the extra CO2.
None directly. Provide supplemental oxygen if
indicated. Don’t attempt a procedure that would
cause the patient to retain more CO2, such as
breathing into a paper bag or an oxygen mask
without oxygen being administered through it.
Myocardial infarction May have chest discomfort; normal lung sounds; may be
elderly, female, or diabetic.
Help patient into a comfortable position;
administer supplemental oxygen; ventilate if
necessary to maintain saturation.
Opioid (narcotic)
overdose
Opioids like heroin and morphine cause altered mental status
and suppress the respiratory drive, causing slow, shallow
respirations that deteriorate to respiratory arrest.
Insert OPA or NPA to control airway; perform
head-tilt, chin-lift maneuver; begin ventilations
with bag-valve mask and oxygen.
Psychogenic
hyperventilation
Psychological trigger; normal lung sounds; carpopedal spasms;
numbness in face, hands, or feet.
Help patient into a comfortable position; coach to
control breathing; administer supplemental
oxygen. Do not use paper bags or other home
remedies.
By no means is this an exhaustive list; just be sure to keep your mind open to the possibility
that someone who is having trouble breathing is experiencing a problem not related to the
respiratory system.
An alert, 80-year-old male complains of sudden shortness of breath. His skin is pale, cool,
and moist. He tells you he began feeling this way about an hour ago, while he was sitting and
reading a book. His vital signs include a respiratory rate of 16 breaths per minute, his pulse is 90
and regular, and his blood pressure is 160/96 mm Hg. He has a history of high blood pressure and
diabetes, and is allergic to bees. Lung sounds are clear bilaterally. His oxygen saturation level is
97 percent. You should (A) administer high-flow oxygen via a nonrebreather mask.
(B) place the patient in position of comfort.
(C) encourage him to drink some orange juice with sugar.
(D) assist with an epinephrine autoinjector, if he has one.
The right answer is Choice (B). Although the patient’s presentation is vague, his age and a sudden
onset of feeling short of breath point to a possible myocardial infarction. Keeping the patient calm and
comfortable is key to preserving myocardial tissue. Although the patient feels like he is short of breath,
there’s little evidence of respiratory distress. High-flow oxygen, Choice (A), is not warranted. He is
alert, suggesting hypoglycemia, which Choice (C) alludes to, is not the culprit. There is no evidence of
a severe allergic reaction as Choice (D) implie
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| Description |
Illustration from Anatomy & Physiology, Connexions Web site. http://cnx.org/content/col11496/1.6/, Jun 19, 2013.
|
| Date | |
| Source | Anatomy & Physiology, Connexions Web site. http://cnx.org/content/col11496/1.6/, Jun 19, 2013. |
| Author | OpenStax College |
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