6. Ventilatory Support

Question 1

Sx of OSA

Answer 1

Snoring framed by breathing pauses
Excessive daytime sleepiness ( maybe even during driving)

May have compensated resp acidosis, hypertension

Question 2

Ix of OSA

Answer 2

First assess sleepiness using Epworth

Home sleep study- AHI
Only consider polysomnography if unclear or no high AHI index

Question 3

WHat is needed for Dx of OSA

Answer 3

• 15 apnoeas → desaturation of more than 4%
• If less than 15 can do polysomnography

Question 4

What diseases is sleep apnoea assoc with

Answer 4

• Assoc with heart disease/ CV disease
• cognitive impairment
• RTA

Question 5

when is CPAP used and when is BIPAP used

Answer 5

CPAP for OSA, BIPAP for acute TIIRF and COPD exacerbations

Question 6

mx of OSA

Answer 6

Weight loss then CPAP if moderate or severe OSA
mandibular device for pts with mild OSA

Question 7

When can domicillary NIV be given

Answer 7

• if have chronic respiratoru hypercapnoea
  
  • 2 levels of pressure delivered
  • Designed to reverse TIIRF by increasing ventilation
  • Chronic TIIRF eg.. NM failure, MND etc

Question 8

Which pts can be given LTOT

Answer 8

• For chronic hypoxaema
• PaO2 < 7.3, checked x2 3 weeks apart, 6 weeks since exacerbatn
• Slow progression of pulm HTN, decrease in mortality

Question 9

When should pneumonia patients be admitted or sent to ICU

Answer 9

CURB 65 is 3 or more

Question 10

What is target SPo2 for acutely unwell pts ( both scales)

Answer 10

94-98% vs 88-92 if risk of chronic hypercapnoea

Question 11

When should venturi mask be given

Answer 11

If target 88-92 or unwell with type I

Question 12

oxygen range from venturi

Answer 12

Fio2 24-60%

Question 13

Define RF

Answer 13

• PaO2 < 8kPa * breathing air
• or PaCo2 >6.5 kPa

Question 14

Possible compensation for hypoxia

Answer 14

Mild resp alkalosis due to blowing off Co2

Question 15

If pt is hypercapnic and Pa02>8, is this RF

Answer 15

yes

Question 16

pH in chronic TIIRF

Answer 16

may be normal due to raised bicarb to compensate for resp acidosis

Primary resp acidosis with sec metabolic alkalosis???

Question 17

Acute on chronic TIIRF tx

Answer 17

give venturi and reduce oxygen supplementation so pH comes up. If pH doesn’t come up then give NIV

Question 18

What does +ve and +ve BE mean1

Answer 18

High means alkalosis, low means acidosis

Question 19

Compensation for metabolic acidosis

Answer 19

Kussmaul breathing, hyperventilation to blow off co2

Question 20

what drugs can cause respiratory depression, CO2 retention and hypoxia

Answer 20

BENZOs

Question 21

What does it mean if there are more lung markings centrally than periphally

Answer 21

Could be pneumothorax

Question 22

What does reduced lung markings peripherally possibly suggest

Answer 22

CF exacerbation

Question 23

Causes of RF

Answer 23

COPD, Pneumonia, PE, ARDS, Lung cancer
MSK, NS disorders like GBS or ALD, sepsis, drug overdose

Question 24

What resp condition can cause TIIRF

Answer 24

COPD and PE - increases physiolgical dead space- areas of lungs are ventilated but not perfused, leading to wasted ventilation and hypercapnia

Question 25

Fx of RF

Answer 25

dyspnoea, tachypnoea, and use of accessory muscles. Cyanosis may be present in severe cases, reflecting a significant decrease in arterial oxygen saturation. There may also be confusion or altered consciousness due to hypoxia and hypercapnia

Question 26

What is a compensatory response to chronic hypoxia

Answer 26

Polycythaemia - increased RBC production

Question 27

Ix for TIIRF

Answer 27

ABG- diff TI or II FBC, d-dimer, trop, NT-proBNP for HF CXR or CT if PE suspected