Lecture 1 - Resp Failure and Intubation

Question 1

Define Respiratory Failure

Answer 1

1. Patient loses the ability to ventilate adequately

2. Patient can’t deliver enough O2 to the blood and organs

Question 2

Define hypoxaemic RF with regards to:

1. PaO2

2. PaCO2

Answer 2

Type 1
O2 movement impairment
PaO2 < 60 mmHg
PaCO2 < 42 mmHg

Question 3

Define hypercapnic RF with regards to:

1. PaCO2

2. The respiratory pump

Answer 3

1. PaCO2 > 50 mmHg

2. Respiratory pump is inadequate and cannot maintain ventilation to eliminate CO2 produced by metabolism

Question 4

Define the following types of RF:

1. Acute
2. Chronic
3. Acute on Chronic

Answer 4

Acute
- rapid, short course, pronounced symptoms

Chronic
- long duration with poor ABGs, has metabolic compensation

Acute on Chronic
- acute exacerbation of chronic COPD

Question 5

What are the Mechanisms of Hypoxaemic RF

Answer 5

1. Reduced gas going to areas with normal perfusion (LLV)
2. No gas going to areas with perfusion (atelectasis)
3. Diffusion impairment (pulmonary fibrosis)
4. Gas going to area with reduced perfusion (PE)

Question 6

What are the Mechanisms of Hypercapnic RF

Answer 6

Impaired Neuromuscular function
- cervical spine injury, respiratory mm dysfunction

Depressed Drive
- opiate overdose, brainstem injury

Impairment of the LOAD

• increased airway resistance (asthma)
• reduced chest wall compliance (kyphoscoliosis)
• reduced lung compliance (collapse)

Question 7

Hypoxaemia - Clinical Manifestations

5

Answer 7

1. Reduced mental acuity (if PaO2 < 40-50 mmHg)
2. Agitation -> somnolence
3. Dyspnoea
4. Increased RR
5. Organ failure

Question 8

Hypercapnia - Clinical Manifestations

Answer 8

*depends on rate of CO2 rise and amount of compensation!

1. Dyspnoea
2. Increased RR
3. Agitation/Confusion
4. Coma
5. Increased ICP, HA

Question 9

What are the reasons for intubation?

Answer 9

1. Maintain pt upper airway (suffocation)
2. Protect LRT (aspiration)
3. enable adequate tracheobronchial toilet - Allows to clean out excessive secretions
4. Allow ventilatory support (mechanical ventilation during paralysis/sedation; O2 therapy - CPAP/PEEP)

Question 10

What is, and, How do you find V*E

Answer 10

Minute ventilation

RRxVT

Question 11

What is V*A and what is its equation

Answer 11

V*A = alveolar ventilation

1) (Vt-Vd) x RR
2) VE - VD

Question 12

What is V*d and how do you find it

Answer 12

V*D = dead space ventilation

RRxVd