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The importance of normal breathing with
the occasional deep sigh breath.
Normal in and out quiet breathing is called the
tidal volume (Vt) because, like the tides of the
seas, it goes in and out on a regular basis. This
quiet breathing tends to inflate only 10% of the
total lung capacity (TLC)
The Vt of a 150 lb, six foot tall male is about
500-600 mL. This is about 10 mL/Kg of IBW (ideal
body weight) see below for IBW formula
The units of volume for the lungs are the liter
(L)
or the milliliter (mL)
Normal VT requires use of the diaphragm
and the intercostals muscles: the primary muscles of
inspiration.
A normal person sighs about 1-3 times an hour at a
sigh volume of 12-15 ml/ Kg/ IBW. Sometimes these
sighs are obvious such as a yawn--- other times the
sigh is more subtle, but it is always present in the
healthy person,
If a person did not sigh occasionally, his dependent
alveoli (the air sac on the bottom of the lungs)
would start to deflate and these alveoli would start
to collapse.
This condition is called alveolar atelectasis or
atelectasis
5 steps of a cough and the physical
requirements needed for a person to cough effectively.
For a person to cough effectively there must be a sequence
of events.
· Deep inspiration:
to cough effectively one must take in a deep breath of an
inspiratory capacity (IC) of at least 12-15 ml/Kg IBW. Most
deep breaths are 2 to 3 x that minimal number. To get this
additional gas into the lungs the patient must use, not only
the primary muscles, but the accessory muscles of
inspiration. These are chest wall muscles: both anterior and
posterior.
-
Expulsion:
Open the glottis-suddenly. With positive pressure on the
glottis, as soon as it flies open, the resulting
exhalation is quite fast with speeds (flow rates) of
300-500 lpm. This velocity will shear off secretions in
its way.
The effect of chest or
abdominal surgery on the patient's ability to breathe and to
cough effectively.
The person who has had upper abdominal or chest surgery will
have a poor cough for several reasons.
-
Skeletal muscles are traumatized.
The incision cuts through muscles and they are discoordinated.
-
Pain:
the incisions hurt these muscles. The patient tends to
splint his muscles by restricting his movements and by
breathing shallow and fast. He will stifle his cough.
-
Immobilization:
the patient in pain will restrict his movements and
tends to lie in bed in only 1- 2 positions so that
alveolar ventilation is limited to only some parts of
the lung. The parts of the lung that face the bed will
start to collapse first with secretions pooling in the
dependent areas [areas that are faced down]
-
Sedation:
when the patient gets enough sedation that it doesn't
hurt to breathe, he will tend to breathe even more
shallowly than before. Pain medication dampens the
ventilatory drive. The brainstem is slow to recognize
that the C02 is rising
-
Drugs:
many of the drugs used during surgery have the added
effect of increasing the thickness of oral and lung
secretions as well as increasing them. Morphine is known
for this increase in secretions
-
Artificial airways:
while the patient was unconscious and not breathing, he
had a tube pushed between his vocal cords. This tube was
attached to a ventilator which gave him his breaths. The
tube itself is a horrible irritant that will cause an
increase in secretions as the lung tries to washout the
object.
Thorocotomy
(cutting into the thorax) will cause lung collapse because
the atmospheric air enters the chest wall to push on the
alveoli from the outside.
Also, the thoracic cage integrity is compromised if the
sternum (breast bone) has been cut. The person with an
unwired sternum is most at risk.
The chest wall cannot rise and create the negative pressure
so needed for a cough.
|
The result of some
or all of these problems is a condition called
post-operative atelectasis.
This complication is the most common and can
generally be prevented by relatively simple and
cheap techniques. |
Problems with
post-op atelectasis
-
Increases the work of breathing as the lung compliance
drops
-
Decreases the total surface area for gas exchange in the
alveoli so that oxygen and carbon dioxide cannot move
effectively
-
Retained secretions will become infected and bacterial
pneumonia can result
The signs &
symptoms of post-op atelectasis
Breath sounds decrease (called diminished) or disappear
(called absent) in the basal posterior areas of the lung;
while inspiratory crackles will be heard over areas with
consolidation
-
Poor chest excursion: chest wall may not move well
-
More labored breathing [using accessory muscles and
retracting]
-
Fever
-
Chest pain on inspiration
-
Dullness to percussion over these areas
-
The x-ray may or may not show signs of atelectasis
-
In pneumonia the x-ray report may use words like
“consolidation”, “lobar or segmental consolidation”,
“infiltrates”
The first three days are the most critical in avoiding
post-op atelectasis
Means to avoid or minimize the
chances of post-op atelectasis
-
Frequent turning
with deep breathing and cough: these are standing orders
in most post-operative patients. Nurses do this on a
schedule (Q2-4 hours) but the RCP can augment this.
-
Incentive spirometry:
this is a device that measures the patient’s inhaled
volume so that the RCP can entice the reluctant patient
to breathe deeper
-
Blow bottles
are outdated because they can affect the blood pressure
-
IPPB and BiPap or CPAP:
are expensive and done only if the first 2 methods fail
The
indications, contraindications & hazards of the Incentive
Spirometry
Indications
·
Presence of conditions
that lead to atelectasis
o
Upper abdominal surgery
o
Thoracic surgery
·
Surgery in COPD patients
·
Presence of atelectasis
in the X-ray
·
Presence of restrictive
disorders associated with quadriplegia (please, watch
the Inspiratory capacity--- the patient must be able to
reach an IC of 10 ml/kg IBW- if he cannot he needs
IPPB.)
Contraindications
-
Persons who cannot do IS, because they are unable to
co-operate
-
Persons who cannot move an inspiratory capacity
(IC) of
33% of their predicted Inspiratory Capacity (IC) or have
a vital capacity (VC) of 10 ml/kg/IBW or less
-
Presence of an artificial airway is NOT a
contraindication for IS if the correct adapters are used
(but, remember, that we could just bag that person
with a slow deep breaths and inspiratory hold with the
bag—for free!)
Hazards
-
Ineffective
-
Inappropriate as sole treatment of major atelectasis or
consolidation
-
Hyperventilation as the patient breathes deeper and
faster, the C02 is blown off and cerebral
vessels constrict: leads to dizziness & tingling of the
fingers
-
Barotrauma (pressure-trauma) may occur in persons with
bulbous emphysema
-
Inadequate pain control: check their pain medication
schedule
-
Bronchospasm: triggered by breathing deep through the
open mouth. Use MDI with Beta II bronchodilator/ or
perform deep breathing with nose breathing and segmental
breathing [see below]
-
Fatigue: the RCP must watch the patient’s WOB
Calculate the ideal body weight [IBW] of the adult male:
Although
the slip of paper with the incentive Spirometer contains the
IC maximal that the patient needs to work toward, invariably
these directions get lost. So we need to know how to arrive
at this figures.
Formula:
for the first 60 inches of height (5 feet) give the male
patient 105 pounds
Then add 6 pounds per inch over 60 inches.
Example: Mr. Johnson is 62 inches tall,
his IBW is= 105 + (2 x 6)
105 + 12 = 117 pounds is Mr. Johnson’s IBW
Calculate the ideal body weight
[IBW] of the adult female
Formula:
for the first 60 inches of height (5 feet) give the female
patient 100 pounds
Then add 5 pounds per inch over 60 inches.
Example: Mrs. Raines is 62 inches tall,
her IBW is =
100 + (2 x 5)
100 + 10= 110 pounds
The next step is to convert pounds into kilograms
-
To convert the pounds into Kg, the RCP will divide the
pounds by 2.2.
-
The RCP will use the IBW to calculate the minimal goal
that the patient must do on an IS.
1.
So Mrs. Raines who
has 110 pounds IBW/2.2 = 50 kg IBW; she must get an initial
goal on the IS of at least (12 x 50) 600 ml on the IS
2.
The male patient, Mr. Johnson, is 117/2.2 = 53 Kg IBW; he
must get an initial goal on the IS of at least (12 x 53) 639
ml.
Using the graph that comes with the IS device, select a
reasonable goal for your post-op patient.
-
Find the patient’s age, then height in inches then look
for the IC.
-
This reasonable goal will be more than 3 x the minimal
goal
-
The patient should work toward this goal. Each time he
gets a higher IC on the IS increase the goal to that
level
Identify the 4 lung volumes and discuss the effect of
decreasing lung volumes on the patients
Definitions of the 4 lung volumes:
-
Inspiratory reserve volume: IRV:
what can be inhaled from the end of a normal breath
-
Tidal volume
VT: what is inhaled and exhaled every
day; a normal breath
-
Expiratory reserve volume: ERV:
amount of gas that can be exhaled from the end of a
normal breath
-
Residual volume: RV:
volume of gas that stays in the lungs at the end of a
vital capacity. All the air that can be removed is
removed.
Definitions of the 4 lung capacities:
Each lung capacity is the sum of two or more lung volumes:
TLC = IRV + VT + ERV + RV
(100%)
VC = IRV + VT + ERV
(80% of TLC)
IC = IRV + VT
(60% of TLC)
FRC = ERV + RV (40% of TLC)
As excessive numbers of alveoli collapse, there will be a
decrease in the FRC, because the residual volume decreases.
As the residual volume drops, the lungs get stiffer and the
lung compliance drops; due to LaPlace’s Law.
This will increase the work of breathing.
Describe the directed cough technique used to mobilize
secretions in the person for whom the FRC is decreased.
(Atelectasis, pneumonia; post-op patients with no lung
history)
· Patient takes a slow, deep breath with an inspiratory hold
of 3-5 seconds then coughs into a towel.
· This is contraindicated in cases of:
Unstable neck, spinal injuries, and in closed head injuries
Myocardial infarction
Increased intracranial pressure (ICP) or a known aneurysm
Compare the special problems in secretions
mobilization of persons who have muscle weakness or
disco-ordination such as a paraplegic or the person with
neuromuscular disorders.
The person with muscular weakness or a neuromuscular problem
may not be able to move 12-15 ml/kg IBW due to muscle
weakness. He will understand directions, but will lack the
motor coordination or the strength---or both. His FRC will
be decreased just as the post-op atelectasis patient's is
decreased. He may, also, have basal atelectasis.
The IS technique is not effective for this person, who may
not be able to get 10ml/Kg IBW, so the RCP should recommend
alternative care options such as IPPB or BiPAP to administer
the deep breaths with pressure [such as you had with the
resuscitator bag] These machine will increase the driving
pressure needed to move gas down the airways of the lung.
Discuss the type of cough that works with this person:
Give the deep breaths with the IPPB, have the patient hold
that inspiration, then cough out the breath
Remember he cannot inhale without help
Push on his abdomen with a pillow to augment the weakened
abdominal muscles. Apply pressure only during the expulsion
phase of the cough. Don’t interfere with the inspiratory
phase
How does the RCP cough the person with an increased FRC?
The person with an obstructed airways, such as asthma, or
chronic bronchitis, COPD may have air trapped in the
peripheral areas of the lung. This will increase the RV,
which in turn will increase the FRC.
This person has trouble getting air out--not in, like the
other two persons who have trouble getting air into the
lung.
Assisted cough for the person with bronchospasm and air-trapping
-
This patient is NOT asked to take a deep breath, rather
you ask him to inhale normally by nose (deep breath via
the mouth can trigger more bronchospasm)
-
From the end of a normal inspiration, the patient starts
to exhale via his mouth but he keeps his lips pursed so
that there is a bit of a ‘raspberry’ noise or an
exaggerated sigh. This action will stable the airways,
keeping them from collapsing before the breath is ended.
More air exits the lung. This air will carry the
secretions in front of it.
-
This patient will not cough until he has exhaled half of
his air.
-
At this midway point, he will cough several small coughs
rather than a single big one
-
He must cough into a napkin so that the back pressure is
maintained at all times.
A variation of this type of cough is the ‘tussive
squeeze’
-
The RCP wraps a towel around the bottom half of the
patient’s rib cage. While standing behind the patient,
she pulls the two ends of the towel together.
-
This action will decrease the diameter of the lower
chest wall and assisting the accessory muscles of
exhalation. More gas will exit the lung
-
The RCP must let the patient set the timing on this. She
should never be tightening the pressure on the chest
while the patient is trying to inhale with pursed lips.
-
This can be done during the exhalation as well as during
the expulsion phase of the cough. (keep the napkin in
front of the face)
-
Don't do it if it hurts. If the patient likes it, he
will let you know. If he has intercostals muscle pain
from coughing, he may not let you do this.
Types of IS devices.
-
Volume-orientated IS devices:
A chamber is emptied by the patient’s inhalation.
Because the chamber actually holds 1.5 liters or 3
liters it is big
-
Flow-orientated IS devices:
measures flow. If one inhales at 100 ml/sec for three
seconds, one has inhaled a volume of 300 ml. To use this
device, one must maintain the flow rate at the optimal
level (usually have floats to tell you where the ideal
flow is)
Of the two types which requires some form of gas
flow regulator or gas flow indicator to work properly?
The flow-orientated IS needs a flow regulator or indicator
to work properly. If the patient inhales too fast or too
slow the volume indicator is incorrect
The effect of dampness on the
effectiveness of the IS device.
Try to keep the patient from exhaling into the device.
This will only add water to the insides of the IS and some
of the balls and other guides may stick and make inhalation
more difficult.
This will also add germs to the inside of the device and
while they are the patient’s germs---they are still germs.
Directed Cough
When the patient’s cough is not spontaneous, rather it is
initiated by the RCP it is called a directed cough.
Indications include:
-
Need to remove excessive secretions from the central
airways
-
Presence of atelectasis
-
Post-op prevention of increased secretions
-
Part of the routine bronchial hygiene in persons with
abnormal secretions such as Cystic fibrosis,
bronchiectasis or chronic bronchitis, spiral cord injury
-
Part of other Rx that are involved with mobilization of
secretions
-
To obtain sputum for diagnosis
Contraindications for directed cough are all relative:
Assisted cough with pressure on the abdomen is
contraindicated in situations in which there is
Assisted cough with pressure on the chest wall (tussive
squeeze) is contraindicated when there is:
Hazards of coughing
-
Reduces coronary artery perfusion
-
Reduces cerebral perfusion
-
Incontinence
-
Fatigue
-
Headache
-
Numbness
-
Bronchospasm
-
Muscular discomfort
-
Spontaneous pneumothorax
-
Cough paroxysmal (use purse lip breathing to get out of
that)
-
Chest pain
-
Rib fracture
-
Incision pain
-
Retinal hemorrhage
-
Central line displacement
-
Gastroesophogeal reflux (may have to work around feeding
schedules)
