Why Hospitals Should Be Required To Have Isolated Power

Many feel the only purpose for Isolated Power is for flammable inhalation anesthetizing locations. But that is not true!

The NFPA 99 2005 Edition 4.3.2.2.8.1 states that if the area is a  "Wet Location" the patient care area shall be provided with a special protection against electrical shock. This special protection shall be provided by a power distribution system that inherently limits the possible ground fault current due to a first fault to a low value, without interrupting the power supply." In that same section 2 4.3.2.2.8.4 states that Isolated Power shall be permitted as the protective means capable of limiting the ground fault without power interruption. Some say all Operating Rooms are not "Wet Locations" and that maybe true at the beginning of the operation but what happens when there is a spillage. NFPA 99 2-6.3.2 Note 2 mentions that "Patients and personnel "OFTEN- are wet with prepping solutions, blood, urine, and other conductive fluids that greatly reduce resistance to the passage of unintended electrical current. More than ordinary care is crucially necessary in the use and maintenance of all electrical systems and equipment." Since accidents do happen the, "more than ordinary care", would include Isolated Power, for the safety of the patient, doctors and nurses that may find themselves in fluids during an operation.

NFPA 99 General says " Medical and nursing sciences are becoming progressively more dependent on electrical apparatus for the preservation of life of hospitalized patients. For example, year by year more cardiac operations are performed, in many cases the patient's life depends on artificial circulation of blood; in other operations, life is sustained by means of electrical impulses that stimulate and regulate heart action; in still others, suction developed by electrical means is routinely relied on to remove body fluids and mucus that might otherwise cause suffocation." Interruption of power can cost a patient their life, that's why the hospital has emergency back-up power. But what good would it be if due to a spillage of fluids on the floor during an operation the breaker trips, if it was on grounded power?  That's what would happen without isolated power.  

On Isolated Power the equipment stays on and the hospital personnel receives an alarm to let them know there is a potential problem. The circuit breaker only trips when you have a line to line fault. Also NFPA 99 under Recognition of Hazards and Responsibility discusses the ultimate responsibility for care and safety of patients in a hospital is that of the governing board of the hospital, and the responsibility falls mutually upon all physicians using the anesthetizing locations, the administration of the hospital, and those responsible for hospital licensing, accrediting, or other approval programs. So due to the extra protection Isolated Power provides the patient, medical personnel and all engineers should recommend it in all  operating rooms. If the hospital still determines removing, isolation power or, in the case of a new hospital, forego installing it, the engineer would be wise to get that in writing from the hospital administration to protect themselves from a law suit later if an accident occurs.

North Carolina and Michigan have made it mandatory to have Isolated Power in all Operating Rooms. At one time NFPA was making an investigation about electrical shocks in operating rooms where they had taken Isolated Power out. To this date we have not heard the out come of their findings. But where there is smoke you can bet someone got burned, whether or not they publish it.

Please find the reasons to keep Isolated Power in all Operating Rooms:

1. Reduced Shock Hazard

2. Continuity of Power

3. Line Noise Reduction, the transformer acts as an electrical filter.

4. Advance warning system of what their equipment condition is.

5. Reduced Fire Hazard

6. Extra level of protection will keep down liability claims. Isolated Power Many do not want Isolated Power because of what we call "nuisance alarms" as a result of adding more and more equipment to the Isolated Power Distribution System. The Line Isolation Monitor may be an old 2 Ma trip point and needs to be changed out to a 5 Ma LIM. This solves that problem and if they get an alarm it's because they truly have a leakage problem. When they first had flammable gases they saw they needed to keep down electrical sparks which could ignite the gases and cause explosions in operating room. The first attempt of a warning system was with Static Ground Detectors. They contributed about 1,000 microamperes to the system leakage and they monitored an imbalance between each line to ground. That meant that if each line was leaking, say IO milliamperes to ground, it said you were safe. So they continued to have problems. To this date there are some of these units still out there working because under the Grandfather clause they can keep the equipment until they move it. Then they must bring it up to date. Later they came out with Switching Line Isolation Monitors. What they did was sample one line to ground then switch over and test the other line to ground. This was a better system but it caused interference with physiological monitors due to the sampling of each line. The reed relay in the Switching Line Isolation Monitor would switch at a rate of sixty times per minute to each line, thus a 120 beats per minute pulse.

The NFPA 99 Section 3-3.2.2.3(g) states that the Line Isolation Monitor shall not generate energy to create interference or artifact on human physiological signals. Again to this date there are many of these units still out there working and should be brought up to date. Again changes were made and they came out with a true Line Isolation Monitor that tested both lines at same time to ground but they were 2 Ma trip points. Also many of the old LIMs added about 500 microamperes to system leakage.

Today's LIM adds only 25 microamperes monitor hazard and trips at 5 Ma. Our suggestion is to up grade all Ground Detectors and Line Isolation Monitors to our new 5 Ma LIM. At the same time the hospital should look at the size of the Isolation Transformer that they have. We have found that over the years they have added more and more equipment with out changing their transformer. Please find Technical Awareness Announcement "Are Your Operating Rooms About To Shut Down?" Also find copies of NFPA 99 and other Press Releases along with our new catalog. Notice our new Laser Power Supply that allows more than one Laser outlet to be on at any one time.