Droplet size (mass median diameter/MMD) in eFlow and Pari Boy SX

Question

Hello,

for 0,9% sodium chloride (aq), the data sheets for eFlow and Pari Boy SX specify (with the same measuring method) an MDD of 3.9µm for the eFlow, 2.9µm for the Boy SX with blue nozzle insert in the LC Sprint nebulizer, and 2.2µm for the red one.

Earlier, I was supposed to nebulize Tobi® (tobramycin) and sodium chloride with the blue LC Plus (now Sprint) nebulizer, and Pulmozyme® (dornase alfa) with the red LC Star (now SprintStar) due to the smaller droplet size.

Now I was prescribed an eFlow for Colistin. The manufacturer recommends both LC Star or LC Plus, but says that LC Star should be preferred. In my clinic, I was told I could also nebulize dornase alfa and sodium chloride 0.9% with the eFlow.

It seems somewhat of a contradiction to me if I was supposed to nebulize dornase alfa at a droplet size of 2.2µm earlier and now (according to the manufacturer) it is possible to reach a size of 3.9µm with the eFlow.

Can I inhale sodium chloride and dornase alfa with the eFlow without hesitation (FEV1 1.54)?

Thanks and kind regards.

Answer

Hello,

the droplet size should not be overestimated, since droplets of the same size do not always behave the same way: they can shrink (due to vaporization of water) or take in water and hence grow. The droplet size does influence the deposit in the lower and less lower respiratory tracts, but since the matter with the shrinking/swelling is very complicated, one has to try this out in studies. This will then be the basis for recommendations about which solution will yield quite good results with which devices. In addition, the amount nebulized per minute has to be considered, which after all is a particular strength of the eFlow.

As a simple rule, one can assume that anything smaller than 5µm has a good chance to reach the lower respiratory tracts.

Kind regards,
Prof. Dr. TOF Wagner

11.01.2011