Your surgical facility holds a wealth of visible technologies: The surgical equipment support systems, or booms, are the arms that reach out to the perioperative field; surgical robotics and image-guided surgical systems are the fingers that touch the patient. The many optical and video systems found in surgical microscopes and minimally invasive endoscopic gear are the eyes.

Enabling these visible technologies are unseen systems that we could view as the facility's skeletal, respiratory, circulatory and nervous systems. Like our own bodies, the visible anatomy works only because of the functional structure under the skin. Let's consider how you must address your building's vital unseen anatomy during design development and construction.

Structure - the skeleton
Just as the skeleton brings shape and strength to the human form, the structure of a building serves the same purpose. In a new facility, the structure you need to attend to is that which supports specialized equipment. For example, if you don't provide adequate structure for the mounting of booms and surgical lights, these devices won't stay put where you park them in the surgical field. Above-ceiling steel supports are also important for ceiling-mounted patient lifts and surgical microscopes.

Microscopes can present special design challenges because you often must mount them on vibration isolation systems that are rated for the weight of a small car. If your new facility will include fixed radiology rooms, the overhead X-ray tube cranes have to be mounted on a special modular steel framework.

The architecture and engineering (A&E) design team needs detailed information from the equipment vendors early in the design process to incorporate adequate (and sometimes massive) steel structures above the ceiling. These mounting structures are directly attached to a building's skeleton, or structural framework.

HVAC - the respiratory system
A surgical facility breathes, drawing breath through the heating-ventilation-air conditioning (HVAC) system, whose requirements are defined by a multitude of national building codes and state regulations. The HVAC system is more than just the furnace and fan in your home; it not only makes the facility comfortable, it plays an important role in both infection control and fire safety.

In an operating theater, a certain number of air changes per hour must occur, meaning that the entire volume of air in the room is completely exchanged over and over. Air enters the OR through special filters - HEPA (high efficiency particulate air) filters - that provide ventilation that is virtually particle-free. Keeping particles and, therefore, pathogens out of the OR air is key to infection control.

Also contributing to infection control is how the HVAC is balanced. This process starts with system design and ends with construction, when you use a special device to measure how much air is coming through each air conditioning register and subsequently adjusted airflow with dampers in the ductwork. Some rooms, such as the OR and sterile storage, are balanced at positive pressure relative to adjacent rooms. The idea is that airborne contaminants are pushed out of and away from these areas. Conversely, negative-pressure areas, such as soiled utility and decontamination rooms, keep airborne contaminants within the space.

Centralized surgical smoke exhaust systems also contribute to infection control by evacuating smoke plumes generated by electrocautery and laser equipment. Research shows smoke can carry live viruses and DNA fragments from the tissue being ablated. These systems therefore provide both microbiological safety and, by eliminating odors, a better working environment for the surgical staff.

Fire dampers in a medical facility's HVAC system are tied to the fire alarm system and shut during a fire in order to reduce the air needed to feed a fire and to prevent the spread of smoke. Most surgical suites also have a special exhaust system designed to evacuate such smoke.

Ethylene oxide gas sterilization is a waning technology, but it is still quite popular. Because exhausting the fumes from these sterilizers and aerators is strictly regulated in terms of fabrication and route to the outside, you must tell your A&E team early whether ETO is a consideration.

Tips for Ensuring High Air Quality Here's a summary of the CDC's salient recommendations regarding your HVAC system that you can take care of during the construction phase. - At minimum, follow the AIA guidelines if there are no state or local rules regulating the design and construction of ventilation systems in new or renovated healthcare facilities. - Properly install and maintain HVAC filters to prevent air leakage and excess dust. - Engineer humidity controls in your HVAC system to incorporate a water-removal mechanism and so the system will completely absorb moisture. - Include steam humidifiers (not cool-mist humidifiers) to reduce the potential for microbes to proliferate. - Locate outdoor exhaust outlets more than 25 feet from air-intake systems, install outdoor air intakes at least six feet above ground or at least three feet above roof level, and locate contaminated areas' exhaust outlets above roof level. - If your facility performs mainly or strictly orthopedics cases, consider installing a laminar flow/HEPA filtration system. However, the CDC environmental infection control guidelines make no specific recommendation for laminar flow for ORs where such cases are performed. - If you do not have horizontal laminar airflow, ensure that your HVAC system is engineered to introduce air at the ceiling and exhaust air near the floor. - Do not install ultraviolet (UV) lights. I don't recommend them, and neither does the CDC. - Dan Mayworm

Plumbing - the circulatory system
The need for hot and cold running water, and sewer lines to carry off waste is pretty straightforward. But a surgical facility also has many other pipes to carry other necessary liquids and gases.

State codes dictate the location and quantities of the medical gas system - oxygen, air and vacuum outlets. Although rarely seen, these gases are delivered by a network of copper pipes engineered to specific sizes based on the number of outlets they serve. Even the type of copper pipe, the solder used to braze the pipe and the methods for brazing the pipe are regulated.

The A&E specifications must spell out the qualifications of the plumber hired to install these systems; failure to do so could result in contaminated medical gases' being delivered to the patient. Have the medical gas system independently certified to ensure there are no cross connections with the pipes - every few years, it seems, a patient death due to the patient's getting carbon dioxide or nitrous oxide instead of oxygen (even though the outlet was labeled oxygen at the patient bedside) is reported.

Steam for sterilizers is another set of plumbing not found in a typical commercial building. In large or cold-climate facilities, house steam might come from a central boiler used for heat and humidification, and the HVAC system might also be used for the sterilizers. Smaller facilities can buy compact steam generators from the sterilizer company to provide steam for sterilization.

Water treated through reverse osmosis or deionization is often needed for instrument washers. It's delivered from the water treatment device to the washer through non-reactive pipe or tubing. This equipment, the space it requires and the special piping are often overlooked during facility design. Another frequently overlooked consideration for instrument washers: the tubes that run from 25-gallon drums of detergent and instrument lubricant. While the washer manufacturer provides detergent tubing sets, you must route them from the drum location (another often-overlooked space consideration) to the device.

Another need unique to surgical facilities is compressed air, which powers pneumatic brakes on surgical booms, actuates doors and valves in instrument washers and some sterilizers, and lets compressed air guns in decontamination blow out the lumens on scopes and instruments. Don't use medical compressed air in decontamination for blowing out lumens; it violates medical gas codes and can also be very expensive if compressed gas cylinders comprise your medical gas system. A small (20-gallon, one-horsepower) air compressor is usually adequate for a surgery center, but it must have a trap to capture particulate oil from the compressor, a water trap, and preferably a small, refrigerated air dryer to mitigate condensation in the air lines.

Electrical - the nervous system
Like the human nervous system, your facility has many sensory and communication functions for taking in, processing and reporting information. The brain would be the facility's computers and servers, and the nerves would be the many networks of low-voltage wiring, patch bays, hubs, routers and switches that connect these devices.

You need your brain and nerves to keep running to stay alive, and so does your surgical facility. Electricity, whether available from the electric company's grid or not, is necessary and the emergency generator is a central consideration in your electrical engineering. You might find that the electrical codes mandating the minimum building systems, lighting and outlets on the emergency generator to be too minimal and want a more robust emergency power system. You must identify this desire early in the design process - but remember that added capacity means added cost, so the facility owner must weigh the cost-benefit of a larger back-up electrical generation system.

Computer systems usually run on uninterruptible power supplies (UPS), a subset of emergency electrical power.

The UPS is most often a small box adjacent to a computer, but some facilities have a house UPS to provide power to mission-critical data systems. Either way, UPS makes computer function uninterruptible. You see, if you lose power, there is a lag time until the emergency generator starts up and transfers. A UPS protects against this momentary power drop in which your computers would go down. House UPS systems are very expensive but are not uncommon; most surgery centers handle UPS on a local-device level with stand-alone systems such as those you can find at your local computer or office supply store.

In non-emergency power, structured cabling is an organized systematic approach to looking at the total low-voltage connectivity requirements - both wired and wireless - of a facility. It includes the wires, the jacks, and the unseen myriad of devices in the data and telecommunications rooms like electronic racks, punch blocks, patch bays and cable trays.

Wired systems that you need to address include data, telephone, intercom, nurse call, background music/overhead paging, television, closed-circuit video, surgical video, time and attendance stations (digital time clocks), security, access control and fire alarm. Wireless systems can include centralized clock systems, cardiac telemetry, pocket phones and two-way radios.

Be hands-on
Your facility is practically a living being. Its eyes and ears are the audio and video systems; its olfactory senses are the smoke detectors in the ceiling and HVAC ducts and the device in the air compressor that sniffs out carbon monoxide. Individual clinical systems have their own noses that detect EtO, gluteraldehyde and volatile organic compounds in the ambient air.

The A&E always takes care of the medical gas alarm and fire alarm systems, and sometimes access control and security; the other systems are almost always owner-provided. You must coordinate in detail with the systems' vendors, A&E team and builder at all phases of design and construction - make clear who is providing and pulling the cables for these systems. Always remember that it's easier and cheaper to make these provisions during construction rather than later.

As the owner or administrator, you must be aware of all systems, seen and unseen. Along with your A&E team, develop checklists and responsibility matrices to outline the systems, who specifies it, who purchases it, who roughs-in (power and wiring) for it and who finally installs it. Approaching these complex building and clinical systems thoughtfully and systematically early on will prevent the pointing of real fingers at the project's end and help ensure the project is completed in a timely and budget-friendly manner.