- CONCEPTS OF VENTILATION - Flashcards
Discuss the advantages of NIV
- avoids the complications of intubation
- lowers intubation and mortality rates
- less expensive than intubation
- decreases risk of hospital acquired pneumonia
- reduces need for heavy sedation and invasive monitoring
- increased comfort
State the contraindications of NIV
- Apnoea
- Cardiovascular instability
- High risk of aspiration
- Decreased GCS
- Claustrophobia / non compliant
- Secretions/vomiting
- Facial trauma
- Nasopharyngeal abnormalities
- Base of skull fractures
- Raised intracranial pressure (ICP)
- Pneumothorax (pre-ICC)
Discuss the possible adverse effects of NIV
- Barotrauma
- Hypotension
- Altered conscious state
- Aspiration risk
- Gastric distension
- Decreased venous return from cerebral vessels
- Pressure sores
- Dry nose and eye irritation
- Conjunctivitis
- Discomfort
- Claustrophobia
- Poor sleep
Define Positive End Expiratory Pressure (PEEP)
- Positive end-expiratory pressure (PEEP) is the pressure in the lungs above atmospheric pressure that exists at the end of expiration. It works to recruit alveoli and reduce WOB
Define intrapleural pressure
- Also known as ‘Intrathoracic pressure’
- Refers to the pressure within the pleural cavity
Define intrapulmonary pressure
-The pressure within the lungs
Discuss lung compliance
- The relative ease with which the lung distends (opposite to lung elasticity - the ease with which the lung returns to normal after being stretched)
Discuss airway resistance
- A measurement of the frictional forces that must be overcome during breathing. This friction is a result of the anatomical structure of the airway resistance of the lungs and pressure from surrounding organs
Differentiate between the indications for intubation and mechanical ventilation
Intubation:
- support ventilation
- protect the airway
- ensure airway patency
- anaesthesia and surgery
- suctioning
Mechanical Ventilation
- IMPENDING OR EXISTING RESP FAILURE DESPITE MAXIMUM TREATMENT
- Cardiopulmonary arrest
- Trauma (especially head, neck, and chest)
- Cardiovascular impairment (strokes, tumors, infection, emboli, trauma)
- Neurological impairment (drugs, poisons, myasthenia gravis)
- Pulmonary impairment (infections, tumors, pneumothorax, COPD, trauma, pneumonia, poisons)
Discuss the goals of mechanical ventilation
- Treat hypoxemia
- Treat acute respiratory acidosis
- Relief of respiratory distress
- Prevention or reversal of atelectasis
- Resting of ventilatory muscles
- increase O2 delivery to cells
- reduce WOB and O2 demmand
Define FiO2
the concentration of oxygen in the air/gas that a person inhales
Define tidal volumes
Volume of gas moving in and out of the lungs during inspiration and expiration
Define minute volume
Volume of gas inhaled or exhaled
- RR X TV
Define respiratory rate
Amount of breaths per minute
Define inspiratory:expiratory ratio
Duration of inspiration : duration of expiration (usually 1:2)
Define pressure support
.The difference between PIP and PEEP
Define flow rate
The speed/velocity of the gas being delivered (will directly effect inspiratory and expiratory times
Explain sensitivity
Trigger for what is counted as a spontaneous breath
Define peak inspiratory pressure
Maxium pressure being delivered during inhalation
Describe Synchronised Intermittent Mandatory Ventilation (SIMV) and include the rationale and indications for it
- pre-set number of breaths to a pre-set TV
- pt can initiate spontaneous breaths
- volume is dependant on pt effort, will not top up breaths
- manditory breaths are synchronised with spontaneous breaths (therefore controls RR and MV)
- less likely to have resp alkalosis
- not filling as much which reduces cardiac comprimise
Describe Assist/Control Ventilation (AC) and include the rationale and indications for it
. - pt able to trigger spontaneous breaths but manditory breaths are not synchronised
- will top-up breaths to a pre-set volume
- increases RR and MV massively and thus resp alkalosis
- PEEP and FRC increase and thus decrease in CO2
Describe Controlled Mandatory Ventilation (CMV) and include the rationale and indications for it
- ventilator doing all the WOB (no spontaneous breaths (pt heavily sedated and paralysed)
- pre-set RR and TV
- lets respiratory muscles rest (can have muscle atrophy when weaned)
Describe Volume control ventilation (VC) and include the rationale and indications for it
- constant inspiratory flow that gradually increases in pressure with inspiration
- works up to a pre-set TV and inspiratory time
Describe Pressure control ventilation (PC) and include the rationale and indications for it
. - constant inspiratory pressure that gradually increases
- works up to a pre-set inspiratory pressure