EBME Forums Forums Maintenance Technical Assistance Rainout in Neonatal Breathing Circuits

The HVAC Tech stated there is no abnormal Humidity levels detected.
The Rain out is present throughout the (newly refurbished in 2011) unit and i cannot feel or detect any draught in the bedspaces highlighted. All windows etc are correctly sealed.
The MR850's are never adjusted by staff and default Invasive is even used for CPAP therapy.
The Airway Temp probe is outside of the Incubator approx 30 cm from the patient wye.
If the Manual HC mode is retained, have any Units adopted it permanently and eliminated rainout?
Alternatively if there are any Units who do not suffer rain out, what devices / circuits etc are you using?
Many Thanks.

Hi Topper

A lot of units have their humidifiers set to 0.0 for humidity compensation i.e. off because of rainout issues, it is quite normal. The nurses do not need to know what has changed, just that something has happened and to report back their thoughts. They probably won't notice the difference on the display (the decimal point won't flash anymore) but they may notice that the temperature displayed is more stable.

It should help but it will not fix it completely. To eliminate rainout, lots of things need to be perfect (which is unlikely) but heating the expiratory limb does seem to help, but not on ncpap's obviously. For these, try an auto-fill chamber to see if it makes a difference. The reason for this is two-fold
1) You aren't suddenly lowering the water temperature by adding a large amount of colder water
2) You aren't interrupting the gas flow when water is added.
As I said earlier, once water droplets have formed (which is not to be confused with misting), it is very difficult to remove them and as it cools the passing gas as it goes over the water, so more water 'rains out'.
Mark

Agree with mark and good answer but you need to check the temperature of the room and the regulation pattern in the humidifier as this will also lead to rain out.you will get better results with auto feeders.

Our NNU had this problem with SLEs, cured by setting the 850s to 0.0 offset.

As this is a service job, you need to make sure the modified humidifiers are labelled and don't drift into other areas where this setting would cause other problems.

(I don't like this inflexibility in the 850. I preferred the old 730 that you could set to suit the equipment and conditions prevailing. This is an advantage of the new Intersurgical humidifier - it has a choice of auto and manual settings.)