Respiratory: Respiratory Support Flashcards

1
Q

What is meant by PEEP? [1]
Give three mechanisms of PEEP [3]

A

PEEP:
- Additional pressure in the airways at the end of exhalation stops the airways from collapsing at the end of exhalation

Positive end-expiratory pressure is added by:
* High-flow nasal cannula
* Non-invasive ventilation
* Mechanical ventilation

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2
Q

How does a high-flow nasal cannula work? [3]

A

Reduces the amount of room air that the patient inhales alongside the supplementary oxygen, increasing the concentration of oxygen inhaled with each breath.

It also 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).

Also, provides dead space washout: normally, dead space is ar that remains in airwaays and oropharnyx, not undergoing respiration. High-flow oxygen effectively clears this and replaces it with oxygen, improving patient oxygenation.

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3
Q

When is NIV normally given (in the day)? [1]
Why? [1]

A

At night (and then ok during the day)
During REM sleep your respiratory muscles are at their weakest

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4
Q

What does recruitment mean? [1]

A

Recruitment refers to a process where bronchioles and alveoli which would normally collapse at the end of expiration, are kept open (more lung volume is ‘recruited’).

The phase of breathing that requires the most energy is the process of overcoming the pressure required to re-expand collapsed segments of the lung

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5
Q

Describe the difference in pressures between CPAP and NIV / BIPAP

A

CPAP:
- One continous pressure

BIPAP:
- Two pressures: high pressure when you breath in and low pressure when you breath out. Difference in pressure helps ventilation

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6
Q

When [5] and where [2] is NIV indicated?

A

Acute T2RF: COPD exacerbations
- Inpatient

Chronic T2RF: At home
- Kyphoscoliosis
- Neuromuscular
- Obesity hypoventilation syndrome
- COPD

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7
Q

Which complications of hypoxia does long term oxygen therapy reduce? [2]

A

Cor pulmonale
Polycythaemia

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8
Q

Describe how NIV works to provide O2 therapy [3]

A

NIV delivers differing air pressure depending on inspiration and expiration.

The inspiratory positive airways pressure (iPAP) is higher than the expiratory positive airways pressure (ePAP).

Therefore, ventilation is provided mainly by iPAP, whereas ePAP recruits underventilated or collapsed alveoli for gas exchange and allows for the removal of the exhaled gas.

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9
Q

Explain how CPAP works (when providing oxygen therapy) [1]

A

CPAP supplies constant fixed positive pressure throughout inspiration AND expiration. It, therefore, is not a form of ventilation, but splints the airways open

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10
Q

What are the indications for NIV? [3]

A

Indications for NIV include:

  • COPD with respiratory acidosis (pH < 7.35)
  • Hypercapnic respiratory failure secondary to chest wall deformity (scoliosis, thoracoplasty) neuromuscular disease
  • Weaning from tracheal intubation

NB: These indications assume that optimal medical management is already in place.

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11
Q

What are the indications for CPAP? [4]

A
  • Hypoxia in the context of chest wall trauma despite adequate anaesthesia and high flow oxygen (pneumothorax should be ruled out using a chest x-ray prior to commencing CPAP)
  • Cardiogenic pulmonary oedema
  • Pneumonia: as an interim measure before invasive ventilation or as a ceiling of treatment
  • Obstructive sleep apnoea
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12
Q

CPAP is often started at [] H2O and gradually increased to reduce hypoxia.

NIV is often started at iPAP [] and ePAP []

H2O is typically increased in [] cm intervals by approximately [] cms every [] minutes until a therapeutic response is achieved.

A

CPAP is often started at 4cm H2O and gradually increased to reduce hypoxia.

NIV is often started at iPAP 10 and ePAP 4.4

H2O is typically increased in 2-5cm intervals by approximately 5cms every 10 minutes until a therapeutic response is achieved.

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13
Q

Based on current evidence CPAP & NIV pressures should not exceed [] cm H2O at any point.

A

Based on current evidence CPAP & NIV pressures should not exceed 25 cm H2O at any point.

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14
Q

Name a complication of having ePAP [1] and iPAP [3] too high

A

ePAP
- hypotension

iPAP
- mask to leak
- reduce patient tolerance
- cause stomach inflation increasing the risk of aspiration.

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15
Q

Oxygen can be delivered in many ways. State the 3 devices used and the oxygen flow rates (L/min) and approximate FiO2s they can give.

A

Nasal Cannula
- 1L/min: 24% FiO2
- 2L/min: 28% FiO2
- 3L/min: 36% FiO2

Simple Face mask:
- 5L/min: 40% FiO2
- 8 L/min: 60% FiO2

Face mask with reservoir (non rebreather mask):
- 8L/min: 80% FiO2
- 10L/min: 95% FiO2

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16
Q

What are the different colours of venturi mask colours? [6]

What are the oxygen flow rate (L/min) for these different colours of venturi mask? [6]

What are the FiO2 (approx. oxygen) delivered for these different colours of venturi mask? [6]

A
17
Q

Label A-F

A

A: Blue
B: White
C: Orange
D: Yellow
E: Red
F: Green

18
Q

Label A-F

A

A: 24%
B: 28%
C: 31%
D: 35%
E: 40%
F: 60%

19
Q

Describe how mechanical ventilation occurs [2]

A

A ventilator machine is used to move air into and out of the lungs.

An endotracheal tube (ETT) or tracheostomy is required to connect the ventilator to the lungs

20
Q

What’s the difference between mechanical ventilation and intubation? [1]

A

intubation: put a tube down your throat intotrachea

MV: is the use of a machine to move the air in and out of the lungs.

21
Q

What are some key modes of MV? [4]

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

22
Q

Explain what is meant by ECMO [2]

A

ECMO: Extracorporeal Membrane Oxygenation

Blood is removed from the body, passed through a machine where oxygen is added and carbon dioxide is removed, then pumped back into the body. The process is similar to haemodialysis but for respiratory support rather than renal support.

23
Q

Explain what is meant by Acute Respiratory Distress Syndrome [2]

ARDS has an acute onset of which pathological features? [4]

A

ARDS: Severe inflammatory reaction in the lungs, often secondary to sepsis or trauma.

Only a small portion of the total lung volume is aerated and has functional alveoli. The remainder of the lungs are collapsed and non-aerated.

There is an acute onset of:
* Collapse of the alveoli and lung tissue (atelectasis)
* Pulmonary oedema (not related to heart failure or fluid overload)
* Decreased lung compliance (how much the lungs inflate when ventilated with a given pressure)
* Fibrosis of the lung tissue (typically after 10 days or more)

24
Q

What is the management of ARDS? [5]

A
  • Due to the severity of the condition patients are generally managed in ITU:
  • Respiratory support to treat hypoxaemia
  • Prone positioning (lying on their front)
  • Careful fluid management to avoid excess fluid collecting in the lung
  • General organ support e.g. vasopressors as needed
  • Treatment of the underlying cause e.g. antibiotics for sepsis
25
Q

Describe the clinical presentation of ARDS [4]

A
  • Acute respiratory distress
  • Hypoxia (with an inadequate response to oxygen therapy)
  • elevated respiratory rate
  • bilateral lung crackles
  • pO2/FiO2 < 40kPa (200 mmHg)
26
Q
A