Asthma

[Pharmacie]

Hello!
Is Metered Dose Inhaler as effective as Nebulizer.
If yes, could MDI be used in asthma exacerbations instead of nebulizer?


Thanks

[Nik]

pMDI
Pros - cheap, easy to carry around, multidose capability, available for most drugs, spacers available to aid drug administration.
Cons - Pts need to have good co-ordination and technique, oropharyngeal deposition (cold freon effect).

Nebulizers
Pros - Suitable for those who cannot use other preparations (pMDI's, DPI's etc), patient co-ordination not required, can administer large doses of medicine.
Cons - Expensive, not portable, if using jet nebulizers will need a source of compressed gas, not prescribable on NHS, need to be cleaned and maintained regularly, source of infection, time consuming per dose.

In the acute asthma situation, nebulizers are preferred as patients are less likely to be able to use MDI's effectively.

[crit care]

pretty much as above...in the acute phase of an asthma attacj you're not going to ahve enough puff to use the MDI, so its not the case of it being less effective..its more the patient isn't going to be able use in order to get the msot out of it!

[Pharmanaut]

pretty much as above...in the acute phase of an asthma attacj you're not going to ahve enough puff to use the MDI, so its not the case of it being less effective..its more the patient isn't going to be able use in order to get the msot out of it!

Coordination solved with up-front use of auto-MDI or Spacer chamber?
Less risk of acute phase developing?

[crit care]

even with a spacer chamber, the patients breathing won't be enough to inhale the drug in from the chamber. In an asthma attack there breathing is shallow and short, if it was me i wouldn't want someone shoving a spacer chamber into my mouth

[_Rob_]

I'm not entirely convinced by some of the arguments posted around 'ere.

• The medicine still has to be inhaled, no matter how good or bad the inspiratory flow is.
• Spacer devices come with both a mouth piece and face mask design - as do neb kits.
• Spacer devices negate the requirement for absolute coordination.

So I guess the question is more about which device delivers the most appropriate dose to the target site. For that I guess we'll need to discuss particle size and lung deposition in restricted airways?

There is some evidence about in-line spacer devices so that MDI can be used on ventilator circuits. The doses vary from 4-10puffs (Salbutamol 100mcg/puff MDI) to replace a 2.5mg Salbutamol neb.

Without wanting to sound even more daft...is there actually any reliable evidence for the use of inhaled drugs in acute asthma? I say IV magnesium...

[crit care]

you could always go for iv salbutamol with a ketamine infusion on top.....

surely with a nebuliser its driven with air so the inhalation requirement fromthe patient is reduced......

[Nik]

you could always go for iv salbutamol with a ketamine infusion on top.....

First I've heard of ketamine used in severe acute asthma.

[crit care]

it is used. used to cause bronchodilation, although usually in critical care, and you'd give it with a background infusion of midazolam to prevent vivid dreams and nightmares. it is excessive and used if the patient is tubed

[_Rob_]

It is a bit theoretical but Ketamine has been proposed as the sedative of choice in patients requiring mechanical ventilation. It is supposed to have bronchodilatory effects and some anti-histamine action. Talked about it but never seen used it used in this way.