Ventilation

Question 1

LIst the changes in physiology btw spontaneous ventilation and IPPV.

Answer 1

• Spont vent utilises negative intrathoracic pressure -> augments VR
• IPPV utilises positive intrathoracic pressure -> inhibits VR -> can decrease CO

Question 2

List 7 contraindications to NIV.

Answer 2

1. Decreased LOC
2. No respiratory drive
3. Inc’d secretions
4. Vomiting
5. Haemodynamic instability
6. Facial trauma
7. Agitation/poor compliance

Question 3

Outline initial vent settings in a standard patient.

Answer 3

• VC
• FiO2 - 100%
• Vt - 6-8ml/kg
• RR - 12
• PEEP - 5cmH20

Question 4

Outline the approach to the acutely crashing ventilated patient.

Answer 4

COLD

• Connection
  
  • Disconnect the patient from the vent
  • Bag the patient on 100% O2
• Obstruction
  
  • Suction the tube
• Location
  
  • Confirm location - ETCO2
  • CXR
  • ? pull it back
• Decompress with bilateral finger thoracostomies
  
  • PTX

Question 5

Discuss the vent settings in patients with COPD/asthma.

Answer 5

• Problem is expiration
• Patient’s are auto-PEEPing
  
  • Treat the problem - bronchodilators down the tube, IV steroids
  • Allow time to expire -> I:E ratio 1:4
  • Low TV 4ml/kg
  • Low RR - permissive hypercapnoea
  • Deep sedation
  • No PEEP

Question 6

Discuss the vent settings in a patient with a compensated metabolic acidosis (eg ASA o/d or DKA)

Answer 6

Match the patient’s respiratory rate to the vent RR -> avoid decompensation -> arrest.