Operating Room vacuum system

[Zesti]

Does anybody have any numbers on vacuum-use in an Operating Room?

This particular project has 3 vacuum-connections per OR and 7 OR's in total.

The customer requests 100% simultaneous use of ALL connections but this seems over the top to me, all 21 points being in maximum use 100% of the time.

Any thoughts?

 

[EEJaime]

Well, if you feel confident that in a major event, when the OR's are going non-stop and multiple teams of surgeons are frantically calling for suction, that the savings of a few horsepower or line sizes was worth the risk of killing someone when they aspirate blood and that they will still not need all outlets simultaneously? Go for it. But that certainly isn't a bet I would allow our plumbing department to take. You are talking about life critical equipment.

What is your concern? And it is not that they are going to be used 100% of the time! It is that when you need 100% usage, you have the capacity available for that ONE time when you do need it!

 

[SAK9]

The design guide line I use has the following info for medical suction:



Operating rooms 1-8 9-12 13th onwards

Flow rate(l/m)at
ambient conditions 40 40 40

Diversity factor 1 0.8 0.5

Going by this,you should be using a diversity factor of 1 and your client is right this time.

 

[Zesti]

I can imagine that problems can occur when a vacuumpump-system is much larger than the average vacuum-use.
Depending on the tank, there will be more starts-stops on the pumps and, from what I have heard, if the pumps run only for short periods of time they don't get up to temperature and condensate can become a problem.


@EEJaime:

Of course you are right, we do not want to get in a situation where the capacity will prove not to be sufficient.

However, the thing in this case is that the proposed capacity is almost 4 TIMES the capacity of any other hospital.
And I can't imagine all those others being wrong...


@SAK9:

Would 40 l/m be the total flow for one OR?
In this case there is talk of over 100 l/m for one OR...

 

[SAK9]

It is 40 l/m per outlet,mate.Typically each theatre having 4 outlets so that is 160 l/m per theatre.I am not sure what is bugging you here.Thre is a detailed analysis provided in HTM guidelines.You should not have more than 6~8 stops in an hour so size your receiver vessel accordingly.

 

[Zesti]

> It is 40 l/m per outlet,mate.
> Typically each theatre having 4 outlets so
> that is 160 l/m per theatre.

Yes, those numbers seem to correspond to what we have here.

And you would indeed count those 4 at 100%, continuously?
And then 7 or 8 OR's 100% simultaneous.

So for 7 OR's you would arrive at 7x160=1120 l/m, correct?

> I am not sure what is bugging you here.

What is bugging me is the fact that these numbers are so much higher than any working installations in other hospitals.
And those are working without problems!

So my questions is, why are all those systems working perfectly even though they are apparently designed all wrong judging from these figures???

Should we conclude that there is a large discrepancy between guidelines and the actually occuring daily use of vacuumsystems?

> There is a detailed analysis provided
> in HTM guidelines.

I'm not familiar with "HTM" or what it stands for?
Where can I find those guidelines?

Note: We are sizing the system for the large flows as requested. However, I would still like to know if there is a genuine necessity for having such a large system, knowing that many smaller systems exist in the field.

 

[SAK9]

check this out:

http://195.92.246.148/knowledge_network/documents/Exec_summ HTM 02-01 Part A 2006821104233640.pdf

 

[PEDARRIN2]

Think about sizing the individual OR outlets at 100% as requested, but size the mains/branches at the prescribed diversity - but don't reduce the size as you go upstream.

It is much more likely that an individual OR will need all the outlets, but it is less likely that all 7 OR will need all their outlets at the same time.

You can also maintain a slightly higher vacuum, increase pipe sizes to minimize the vacuum loss, have a larger receiver - all of which could keep the size of the vacuum pump down.

 

[Compositepro]

Technically, trying to store vacuum in a tank is foolish idea. If you select the correct style of pump it will be idling when there is no flow in the system. I've seen many poorly designed systems.

 

[PEDARRIN2]

It may seem like a foolish idea to you, but in a medical facility, you are removing body fluids among other things with the vacuum pump.

The tank not only serves as a "vacuum storage device" it also serves as a receiver for these fluids.

They have to go someplace and I would rather remove them from a tank than try to remove them from the pump.

 

[Compositepro]

Then the tank size would have no relation to the vacuum flow but to fluid flow and is irrelevant to this discussion. I would want to trap these fluids before they got into any piping in the walls.

 

[Zesti]

> It may seem like a foolish idea to you, but in a medical facility, you are removing body fluids among other things with the vacuum pump.
> The tank not only serves as a "vacuum storage device" it also serves as a receiver for these fluids.
> They have to go someplace and I would rather remove them from a tank than try to remove them from the pump.

In fact you would have a vessel in the OR to collect whatever they remove during the operation.
If some of this stuff would get into the vacuumlines the OR-staff are to blame for not emptying their vessel in time. For these instances a separate vessel would be installed before the main vacuumtank.

This does bring me back to the use (flow) of vacuum in an OR. There is only so much you can suck from a patient... so why would you keep sucking away at 100 l/m during the entire procedure? Why have a diversity of 1?

 

[PEDARRIN2]

The vacuum can also be used to remove the waste anaethesia(sp) gases from the operating area. There are some designs that use a separate vacuum system for this but it can be a single system if the vacuum pump is designed correctly.

So there is more than just the fluids from the patient being "sucked" away. There might be other uses for the vacuum outlets in the OR. Sizing the piping for 100% flow in the OR is not that unusual.

Size the piping outside the OR and the vacuum pump using the diversity of the total number of outlets.

They might have a separate vessel in the OR but the vacuum system is used also to suck fluids from patients in other rooms as well - and I doubt they have separate vessels for those requirements. That might be a lot of separate vessels

Again, the central tank is a "repository" for these things and is easier to clean than the vaucuum pump.

 

[PEDARRIN2]

For those of us who have to comply with NFPA 99 for our design of surgical vacuum, the following indicates the receiver is required.

5.1.3.6.1.2 Medical–surgical vacuum sources shall consist of the following:

(1) Two or more vacuum pumps sufficient to serve the peak calculated demand with the largest single vacuum pump out of service

(2) An automatic means to prevent backflow from any on-cycle vacuum pumps through any off-cycle vacuum pumps

(3) A shutoff valve or other isolation means to isolate each vacuum pump from the centrally piped system and other vacuum pumps for maintenance or repair without loss of vacuum in the system

(4) A vacuum receiver

(5) Piping between the vacuum pump(s), discharge(s), receiver(s), and the vacuum source shutoff valve shall be in accordance with 5.1.10.2 except that stainless, galvanized, or black steel pipe shall be permitted to be used.

(6) Except as defined in 5.1.3.6.1.2(1) through 5.1.3.6.1.2(5), materials and devices used between the medical vacuum exhaust and the medical vacuum source shall be permitted to be of any design or construction appropriate for the service as determined by the manufacturer.

 

[Zesti]

I don't think it is a good idea to have sucked away "stuff", coming from an OR or any other place in the hospital, ending up in the vacuumsystem/tank. In general this stuff can contain all sorts of bacteria and infectious material. It would be bad practice to have this ending up in the vacuumtank in the technical equipmentroom where it has to be cleaned out by technical personnel and where it can be a healthhazard to them.

Over here it is customary to put a bacterial-filter before the vacuumtank.