Question 30

College answer

a)

• Haemoptysis, tenacious secretions
• Patients with large air leaks 
• ARDS where controlling dead space is important
• Large minute ventilation (e.g. > 10L/min)
• Need for frequent nebulised medications
• Long term ventilation (needs changing every 3-4 days)

b)

• Avoid fluid – water, perspiration etc.
• Avoid excessive hair
• Avoid metal (metal-backed patches, piercings, jewellery) 
• Do not place over bone
• Roll on to the skin to avoid air pockets
• Do not place over implanted pacemakers 
• Avoid wounds / broken skin  Ensure oxygen not flowing over pads

c)

• Infection – cellulitis and osteomyelitis
• Extravasation of blood / infusion fluid / drugs
• Compartment syndrome secondary to extravasation
• Bone fracture or through and through penetration
• Damage to surrounding structures 

Discussion

This question is a concatenation of Question 15.1 and Question 15.2 from the first paper of 2012. Apart from this, no previous questions have asked about the contraindications for the use of a HME.

Contraindications to the use of a HME include:

• Conditions which demand minimsation of apparatus dead space
• Large volume of secretions or froth 

• Large minute volume ( over 10L/min) 

• Large air leak, eg. bronchopleural fistula

• Long term ventilation

• Frequent nebulised medications

With the defib pads, avoid the following:

• Water
• Vomit
• Sweat
• Excessive chest hair
• Piercings
• Necklaces
• Bony prominences
• Air pockets (burns may occur)
• Implanted devices
• Subclavian lines
• Wounds

With intraossesous needle devices, the following complications occur:

• Osteomyelitis
• Fracture
• "through and through" penetration
• Extravasation
• Compartment syndrome due to extravasation
• Injury to staff (slipped needle)
• Damage to surrounding structures
• Microscopic fat emboli

With sternal approach:

• Mediastinal injury
• Pneumothorax
• Greater vessel injury