Ventilation + Respiratory Flashcards
What is the function of the respiratory system?
Supplies oxygen to the metabolically active tissues and remove the carbon dioxide, the waste product of metabolism.
- o2 + Fuel = Energy + Co2 + H2O
What are the 4 components of respiration?
- Mechanical movement
- Metabolic process
- Gas exchange
- Gas transportation
What is mechanical movement?
Mechanical movement is the movement of gases into and out of the lungs.
What is metabolic process?
Metabolic process within the cell to produce energy.
What is gas exchange?
Gas exchange across the membrane and occurs in the alveoli.
What is gas transportation?
Transportation of gases to and from the tissues by the circulatory system.
What is cellular respiration?
It is the membrane pathway that uses glucose to produce ATP (Adenosine TriPhosphate) which the body uses for energy.
What is Aerobic Respiration?
- Requires oxygen
- Main type of respiration that occurs in most situations in plants and animals.
What is Anaerobic Respiration?
- Does not require oxygen.
- During exercise, the oxygen in muscles is inadequate so aerobic respiration does not occur and builds up lactic acid.
What is respiratory failure?
Acute impairment in gas exchange between the lungs and the blood causing hypoxia with or without hypercapnia.
What is Type 1 Respiratory Failure?
- Low PaO2 (below 8 on room air)
- Hypoxic respiratory failure
What is Type 2 Respiratory Failure?
- Low PaO2 (below 8 on room air)
- High PaCo2 (above 6.5 on room air)
- Hypercapnic respiratory failure
What does a Respiratory Assessment consist of?
- Inspection
- History taking
- Hand inspection
- Respiratory rate
- Chest examination
What are you looking for during Inspection in Respiratory Assessment?
- Cyanosis
- Short of breath
- Cough
What are you information are you seeking in History Taking in a Respiratory Assessment?
- Past medical history
- Family + social history
What are you looking out for in Hand Inspection in a Respiratory Assessment?
- Cyanosis
- Brusing
- Tremors
- Clubbing
What are you looking out for in Respiratory Rate in a Respiratory Assessment?
- Look, Listen, Feel
- Rate
- Depth
- SpO2, PaO2, PaCO2
What are you looking for in Chest Examination in a Respiratory Assessment?
- Chest deformity or scarring
- Tracheal position
- Oedema
Give some examples of abnormal breathing sounds?
- Crackles
- Gurgles
- Friction rub
- Wheeze
Where does Stridor occur?
- Upper airway
- Over trachea
Foreign airway obstruction
Where does Wheezing occur?
- Effects bronchi
- Constriction
- Air trying to pass through the bronchioles
- E.g. asthma; bronchitis
Where does Rales occur?
- Crackles
- Smaller airways
- Fluids in the lungs (alveoli)
- E.g. CHF and Pneumonia
Where does Rhonchi occur?
- Larger airways
- Obstruction or fluid accumulation in the larger airways
- E.g. COPD and Pneumonia
What does VQ mismatch stand for?
Ventilation Perfusion Mismatch
What is VQ mismatch?
- Alveolar gas exchange depends not only on ventilation of the alveoli but also on circulation of blood through the alveolar capillaries.
- It depends both on ventilation and perfusion.
- When the proper balance of o2 and adequate blood flow is lost, ventilation perfusion mismatch exists.
- There are 2 types of mismatch:
Dead space
Shunt
What is Deadspace?
- Deadspace is the portion of the respiratory system where the tidal volume doesn’t participate in gas exchange.
- It is ventilated but not perfused.
- There are 3 types of deadspace:
- Anatomic
- Physiological
- Ventilation assisted
What is Anatomic Deadspace?
- Anatomic deadspace consists of the parts of the respiratory tract that are ventilated but not perfused.
- It consists of conducting airways such as, the trachea, bronchi, and the bronchioles.
What is Physiological Deadspace?
Physiological deadspace consists of alveoli that are ventilated but lack capillary blood flow to pick up oxygen and drop Co2.
What is Pulmonary Shunt?
Pulmonary shunt is the opposite of deadspace and consists of alveoli that are perfused, but not ventilated.
What are some common causes of Shunts?
- Pneumonia or pulmonary oedema (alveoli filling with fluid)
- Tissue trauma (alveolar wall swelling)
- Atelectasis (collapsing alveolar absorption of air without replacement)
- Mucous plugging (air cannot get into the alveoli)
Why are chest drains inserted and what do they do?
- Inserted to allow draining of the pleural spaces of air, blood or fluid.
- Allows expansion of the lungs and restores negative pressure in the chest.
- The underwater seal prevents backflow of air and fluid into the pleural cavity.
What is Positive End Expiratory Pressure (PEEP)?
- PEEP is the application of a constant positive pressure to the airways so that at end-expiration the pressure remains above atmospheric pressure.
- PEEP prevents the alveoli and small airways from collapsing, increases the functional residual cavity; rest-distributes lung water and improves oxygenation.
What is Tidal Volume (VT)?
- Tidal Volume is the amount of air in millimetres delivered per breath.
- The tidal volume can be set in volume control modes (SIMV VC).
What is Peak Flow?
- Peak Flow is the speed at which the tidal volume is delivered in volume control.
- The peak flow is one of the determinants of inspiratory time (I:E ratio).
What is Pressure Support (PS)?
Pressure support is a level of support set above PEEP to assist spontaneous breathing patient’s overcome circuitry and augment spontaneous breathing.
What is Inspiration to Expiration Ratio (I:E)?
- I:E refers to the ratio between inspiratory time and expiratory time.
- The I:E ratio is usually 1:2.
What is Peak Inspiratory Pressure (PIP)?
- PIP is the maximum amount of pressure reached during inspiration.
- The set pressure support (PS) will determine the PIP.
- PS + PEEP = PIP
What are the 4 phases of a breath?
- Expiration to inspiration
- Inspiration
- Inspiration to expiration (cycling)
- Expiration (baseline)
What is Pressure Control Ventilation?
The ventilator delivers a pre-set pressure when delivering a breath, the inspiratory pressure is the control variable; is maintained during the inspiratory phase.
What is BIPAP?
- Provides a set inspiratory pressure (a pressure controlled time triggered, time cycled breath).
- Patient can breathe in between mandatory ventilation (often small breaths).
- Spontaneous breaths are supported with pressure support.
What is Controlled Mandatory Ventilation (CMV) and Assist Control (A/C)?
- Ventilator initiates all breaths at a pre-set rate and volume.
- Used mainly in theatre for paralysed and sedated patients.
What are some Pros of Controlled Mandatory Ventilation (CMV) and Assist Control (A/C)?
- Guaranteed minute volume
- Precise control of VT to limit barotrauma.
What are some Cons of Controlled Mandatory Ventilation (CMV) and Assist Control (A/C)?
- Will overcome high resistance to deliver set VT.
- Breath stacking.
What is Pressure Support/ASB?
- The patient triggers the ventilator and receives a supported breath at a pre-set pressure.
- This can be used as a weaning mode.
What is Airway Pressure Release Ventilation (APRV)?
- This is a pressure controlled mode of ventilation that delivers an almost continuous positive pressure, with intermittent time cycled short breaths at a lower pressure.
- This is generally used on patients with the following:
- Severe Acute Respiratory Failure (SARF)
- Acute Respiratory Distress Syndrome (ARDS)
What are the benefits of APRV?
- APRV maximises the recruitment of available lung tissue and therefore improves oxygenation.
- The sustained high mean airway pressure of APRV aims to promote alveolar recruitment.
- Uses P High and P Low.
What is CPAP (Non-Invasive Ventilation)?
- Provides one form of positive airway pressure therapy.
- CPAP is a method of NIV where the patient breaths against a continuous positive pressure throughout the ventilatory cycle.
- Provides an improvement surface area for gas exchange.
- For patients with hypoxia.
What is BIPAP (Non-Invasive Ventilation)?
- Has 2 pressure settings:
Inhibition Positive Airway Pressure (IPAP)
Exhalation Positive Airway Pressure (EPAP) - EPAP provides the physiological advantages of CPAP/PEEP.
- IPAP is the pressure support on inspiration which actively assists spontaneous ventilation.
