Organ support Flashcards
1
Q
What are the principals of O2 therapy?
A
- high flow, high concentration O2 should be given to any acutely dyspnoeic or hypoxaemic pt until accurate titration can be performed using ABG
- Maintain SpO2 between 92-98- compromise may need to be made in acute on chronic hypoxaemic respiratory failure, or prolonged ARDs when lower values may be ok
- When starting mechanical ventilation use a high FiO2 until accurate titration can be performed using ABG
- Unless being treated for carbon monoxide poisoning or hyperbaric therapy, no need to maintain supranormal levels of PaO2
2
Q
What are the types of respiratory support available?
A
- Oxygen therapy
- High-flow nasal cannula
- Non-invasive ventilation
- Intubation and mechanical ventilation
- Extracorporeal membrane oxygenation (ECMO)
3
Q
What is ARDs?
A
- occurs due to severe inflammatory reaction in lungs- oftern 2ndary to sepsis or trauma
- acute onset of:
- atelectasis
- Pulmonary oedema (not related to HF or fluid overload)
- Decreased lung compliance
- Fibrosis of lung (after 10 days or more)
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4
Q
What is the triad of ARDS/
A
- Acute resp distress
- Hypoxia
- Bilateral infiltrates on chest xray
5
Q
Management of ARDs
A
- resp support
- prone position
- Careful fluid management to avoid excess fluid collecting in lungs
6
Q
How do you tailor mechnical ventilation to a pt with ARDs?
A
- Low volumes and pressures to avoid over-inflating the small functional portion of lung- lung protective ventilation
- Postive end-expiratory pressure is used to prevent the lungs from collapsing
7
Q
How does prone positioning help in ARDs?
A
- Reducing compression of the lungs by other organs
- Improving blood flow to the lungs, particularly the well-ventilated areas
- Improving clearance of secretions
- Improving overall oxygenation
- Reducing the required assistance from mechanical ventilation
8
Q
What are the types of oxygen delivery methods and concentrations?
A
- Nasal cannula: 24 – 44% oxygen
- Simple face mask: 40 – 60% oxygen
- Venturi masks: 24 – 60% oxygen
- Face mask with reservoir (non-rebreather mask): 60 – 95% oxygen
9
Q
What is positive end- expiratory pressure?
A
- End-expiratory pressure refers to the pressure that remains in the airqays at the end of exhalation
- Additional pressure at the end stops the airways from collapsing
- It reduced atelectasis
- Improves ventilation of the alveoli
- opens more areas for gas exchange
- decreases breathing effort
10
Q
How is positive end-expiratory pressure added?
A
- high flow nasal cannula
- non-invasive ventilation
- mechanical ventilation
11
Q
What are the benefits of high flow nasal cannula?
A
- reduces the amount of room air that the patient inhales alongside the supplementary oxygen, increasing the concentration of oxygen inhaled with each breath.
- adds some positive end-expiratory pressure to help prevent the airways from collapsing at the end of exhalation (although this effect is reduced if the patient opens their mouth).
- provides dead space washout. The physiological dead space is the air that does not contribute to gas exchange because it never reaches the alveoli. Dead space air remains in airways and oropharynx, not adding anything to respiration and collecting carbon dioxide. High-flow oxygen effectively clears this and replaces it with oxygen, improving patient oxygenation.
12
Q
What is CPAP?
A
- constat pressure added to keep the airways exapnded
- Not classed as NIV
13
Q
What is NIV?
A
- Involves using a full face mask, hood (covering the entire head) or a tight-fitting nasal mask to blow air forcefully into the lungs and ventilate them
14
Q
What is BIPAP?
A
BiPAP is a specific machine that provides NIV. BiPAP stands for Bilevel Positive Airway Pressure.
15
Q
How does NIV work?
A
- NIV involves a cycle of high and low pressure to correspond to the patient’s inspiration and expiration:
- IPAP (inspiratory positive airway pressure) is the pressure during inspiration – where air is forced into the lungs
- EPAP (expiratory positive airway pressure) is the pressure during expiration – stopping the airways from collapsing
16
Q
What is mechanical ventilation?
A
- used when other forms are contraindicated or inadequate
- Pts require sedation
- ET tube or tracheostomy is required to connect ventilator to the lungs- no leaks should be present
17
Q
Outline the settings on a mechanial ventilator
A
- FiO2 (concentration of oxygen)
- Respiratory rate (breaths per minute)
- Tidal volume (volume of air pushed in per breath)
- Inspiratory:expiratory ratio (the ratio of time spent in inspiration and expiration)
- Peak flow rate (the maximum rate of air flow during inspiration)
- Peak inspiratory pressure (the maximum pressure during inspiration
- Positive end-expiratory pressure (the positive pressure applied at the end of expiration to prevent airway collapse)
18
Q
Modes of mechanical ventilation?
A
- Volume controlled ventilation (VC) – the machine is set to deliver a specific tidal volume per breath
- Pressure controlled ventilation (PC) – the machine is set to deliver a specific pressure per breath
- Assist control (AC) – breaths are triggered by the patient (or by the machine if there is no respiratory effort)
- Continuous positive airway pressure (CPAP) – the patient breathes while the machine adds constant pressure
19
Q
What is ECMO?
A
- Most extreme form of resp support, very rarely used
- Blood is removed from the body and passed through a machine where oxygen is added and CO2 is removed, then pumped back into the body
- Only used short term
- Specialist centres
20
Q
Indications of ET tube intubation?
A
- Apnoea- e.g. unconsciousness, severe resp muscle weakness, self poisoning
- Resp failure- e.g. ARDS, pneumonia
- Airway protection- GCS< 8, trauma, aspiration risk, poisoning
- Airway obstruction: maintain airway patency e.g. trauma, laryngeal oedema, tumour, burns
- Haemodynamic instability- shock, cardiac arrest
21
Q
Routes of ET intubation?
A
- Orotracheal- usually preferred
- Nasotracheal
