Lecture 3a Flashcards
What type of SCI’s can lead to respiratory complications?
In cervical injuries, respiratory complications are the leading cause of mortality being implicated in ~80% of deaths
BUT individuals with lower injuries are also prone to respiratory complications
They are the most prevalent source of morbidity and mortality after SCI
Why are respiratory complications an issue?
261 SCI person study:
- 67% of participants experienced respiratory complications (544 in total symptoms - some more than one complication)
C1-C4 SCI: 84% had respiratory complications
C5-C8: 60%
T1-T12: 65%
9 people died in this study, all of respiratory complications (Only 2/9 with C1-4)
- Fatal for all groups
What are the 3 largest problems/complications?
- Paralysis of the diaphragm and other muscles of INSPIRATION cause ventilatory failure
- Paralysis of the muscles of EXHALATION (Especially forced exhalation/breathing with more force) and coughing
- Losing the ability to cough is a large negative
- Means inability to clear secretions from respiratory tract
- Can lead to pneumonia, ventilatory failure, death etc - Autonomic imbalance (Having parasympathetic predominance)
- Leads to unopposed bronchial constriction and mucous secretion
- No sympathetic means no dilation, meaning mucous cannot be coughed up causing more issues
What happens to the volume of the thoracic cavity and the intrathoracic pressure during inhalation and exhalation?
Inhalation
- Increase in volume of thoracic cavity
- Decrease of intrathoracic pressure
- Air drawn in like a vacuum due to more space
Exhalation
- Decrease in volume of thoracic cavity
- Increase in intrathoracic pressure
- Air pushed out of the lungs due to pressure
What are the 3 main muscles used for inhalation and their individual functions?
- Diaphragm
- Principle muscle
- Dome shaped when relaxed
- Flattened during contraction/breathing to increase volume of intrathoracic cavity/draw air into lungs - Intercostals and accessory muscles
- Stabilizes rib cage (Prevents ribs from being drawn downward with diaphragm
- Elevates ribs during inspiration/pulls ribs out and up (pulling them together)- Accessory muscles:
- Scalenes (Stabilize ribs and elevate first 2)
- Sternocleidomastoid (Elevates sternum during deep inhale)
- Pec minor and serratus ant. (Assist in rib elevation)
- Accessory muscles:
- Abdominals
- Push in against viscera (Organs) at rest to help stretch the dome shape in diaphragm
- Inhale allows abs to relax and viscera to protrude forward allowing diaphragm to flatten
What are the 3 main muscles in DEEPER exhalation? (Not inhaling then resting)
- Abdominals
- Principle muscle of exhalation
- Pushes viscera up against diaphragm
- Flexes the trunk (Decreasing chest cavity size, increasing pressure)
- Stabilizes the 12th rib - Intercostals
- When the 12th rib is fixed (from abs), intercostal pull on ribs together causes depression of the ribs
- Prevents ribs from bulging out during exhalation, pushing air directly up and out - Diaphragm
- Contracts eccentrically for first 2/3 of expiration slowing the outflow of air
Which muscles of inhalation and exhalation are affected with different SCI’s?
Diaphragm - C3-C5
Intercostals - T1-T11
- Sternocleidomastoid C2-C3
- Scalenes - C3-C8
- Pec minor - C6-T1
- Serratus ant. - C5-C7
Abdominals - T6-T12
Any injury above T12 there is going to be some type of breathing issue
What are the effects of C1-C2 injury on breathing?
C1-C2 - No independent breathing or coughing (Needs ventilator)
What are the effects of C3 injury on breathing?
C3 - Independent breathing but quick to fatigue (Ventilatory failure)
- Ventilator initially, may wean off
- No independent coughing, needs assistance
What are the effects of C4 injury on breathing?
C4 - Good diaphragm, sternocleidomastoid and scalene
- No ab activity
- No independent coughing
- Diaphragm may be flat while sitting (or lower than normal since no flexed abs to hold dome shape - easier to rehab laying down to avoid this)
- Ventilator initially, may wean off
What are the effects of C5-C8 injury on breathing?
C5-C8 - Good diaphragm and accessory muscles
- No independent coughing (Although pec Maj can depress sternum and upper ribs)
What are the effects of T1-T5 injury on breathing?
T1-T5 - breath well
- some coughing due to intercostals but its limited since no ab activation
What are the effects of T6-T12 injury on breathing?
T6-T12 - Breath well
- Some coughing abilities depending on level of injury
What are the effects of an injury below T12 on breathing?
Below T12 - Breath and cough well
- BUT some respiratory problems due to possible inactivity
What is paradoxical breathing, and which level of injury are most common to suffer from it?
Irregular breathing patterns due to paralysis of intercostal muscles
- Breathing does occur but the ribs aren’t sturdy due to intercostals paralysis
- causes ribs to be drawn in/opposite direction
Cervical or high thoracic injuries are prone to paradoxical breathing