Last year, a provider set out to build a state-of-the-art operating room (OR) at an existing hospital with 25 ORs in various sizes and conditions. Except for nine newer ambulatory ORs, the rest were more than 30 years old and in desperate need of total overhaul. The strategy was to renovate the existing ORs one by one, starting with those that were smallest and in the poorest condition.

However, an idea surfaced to first build two ORs as a showcase, the “Operating Room of the Future,” to generate discussion.

This led to an interesting exercise in considering what might be the next iteration of the OR. Should it look like something from a Hollywood movie, where the surgeon operates on a human body surrounded by holograms and futuristic digital gadgets? Or is it a metallic, sterile room with a supersized mechanical system at work behind the scenes?

These features would certainly convince the general population that the OR is high-tech and futuristic, but would it work for a surgical team?

A hospital is one of many unique building types that require constant changes and updates due to rapidly advancing medical technologies and progressive surgical procedures. However, in terms of its physical characteristics, the basic design of the OR has been rather static. A surgical director of the hospital called it "one big white box.”

The real question is how to transform this seemingly simple box into a 21st century technology-fueled, infection-free, and sleek surgical environment. Is it as simple as determining the right size? Or are there more factors to consider? Here’s what was discovered through this effort.

Ideal size
The size of an OR should be determined based on the types of operations that will be performed, number of surgical personnel, and size of frequently used diagnostic and medical equipment. Generally, orthopedic, neurological, and cardiovascular surgeries demand larger spaces than other operations.

For the last several decades, the size of ORs has grown steadily. In the ‘70s, the Code of Federal Regulation increased the minimum size of a general purpose OR from 320 square feet to 400 square feet and that of a special OR, such as orthopedic, from 360 square feet to 450 square feet. Then in the ‘90s, the Guidelines for Construction and Equipment of Hospital and Medical Facilities recommended the size of an orthopedic or a cardiovascular OR be a minimum of 600 square feet.

The Facility Guidelines Institute’s 2014 Guidelines for Design and Construction of Hospitals and Outpatient Facilities suggests a clear floor area of 400 square feet and a clear dimension of 20 feet for general inpatient ORs. According to Health Care Advisory Board’s Facility Innovation Brief, most architects and facility planners agree that 600 to 650 square feet is ideal, considering surgical staff circulation space and the amount of mobile equipment required. Today, some hybrid ORs are even as large as 700 to 1,200 square feet.

Having the right size room is one of the most fundamental requirements for today’s ORs. They should be large enough for efficient patient transfer, sterile equipment setup, and roll-in diagnostic imaging equipment such as the C-arm. Also, it should have a large area for circulation so that the staff don’t interfere with an ongoing operation.

That being said, bigger is not always better. Hospitals should resist the temptation to make an OR bigger than necessary because unused space in the room tends to attract unnecessary supply and storage items. Having mock-up ORs in different sizes helps hospitals determine the room sizes that match their specific needs and use space more efficiently.

OR table and boom location
The next step is to determine where to place the operating table. In most cases, the shape of the room is either square or rectangular, depending on the circulation and surgical setup. If the room is large enough, the circulation path will not affect the table location as much, since there will always be sufficient perimeter space around it. On the other hand, a rectangular shape better defines a surgical zone by locating the surgical area at one end and preserving the opposite side for movement.

The designer should also consider where the surgeon, anesthesiologist, and other supporting staff will stand and the workflow of team members that are working together. As the room size and shape and table location are being decided, the location and quantity of the ceiling-mounted booms should also be taken into account. Today's booms are packed with advanced technologies. Most new OR lighting uses LED technology with substantially less heat but brighter and whiter light. The arm also makes it easier for surgeons to move the light, as needed.

An anesthesia machine can also be connected to a ceiling-mounted boom or a retractable column. Typically, this is located above the right-hand side of the patient table. Having an anesthesia boom provides more flexibility, but some hospitals prefer a fixed column since the anesthesia machine typically is not moved from operation to operation like other equipment.

Next, monitor and utility booms should be taken into account. A utility boom provides all types of power, IT, and gas outlets and helps eliminate tripping hazards that are frequently caused by loose cables on the floor. However, the overall number of booms has to be carefully monitored so as not to clog air space above the operating table.

The goal should be to have the minimum number of booms covering all four sides of the table so that equipment can be set up anywhere. In today's ORs, high-definition (HD) cameras, which are able to broadcast an operation around the world in real time, can be located on their own boom or integrated into the OR lighting. All these technologies can be integrated into one system for controllability and efficiency, as well.

Infection control
Although it doesn’t announce itself like other high-tech features, the OR’s mechanical system is arguably the most important element to consider. In 2011, the Centers for Disease Control and Prevention reported that there was an estimated 157,500 cases involving surgical site infections (SSIs) from inpatient surgeries. In order to minimize the risk of SSIs, today’s ORs are often not only supported by a higher air change rate than is required but also are built to meet airborne pathogen-free environment requirements, such as those needed in a “clean room,” or a pollutant- and germ-free space.

In some cases, a structural truss and plenum system are used to maximize mechanical space above the OR table. Typically, the ceiling space directly above the OR table contains a messy, structural boom supporting system and large mechanical ducts. However, the perimeter truss system provides a place where all the booms and equipment can be mounted away from the center of the room. This frees the ceiling space for large mechanical plenum space, allowing for minimized turbulence and uniform and directional laminar flow above the table.

In other cases, a modular stainless steel panel is introduced into the wall and ceiling finishes, which lowers infection sources with a nonporous surface that resists bacteria and germ growth. This panel can even be constructed as a removable system for easier renovation in the future without prolonged shutdown of the OR.

Other technologies
Beyond the basics, ORs may also include advanced imaging tools, patient information
technologies, and even virtual surgical navigation systems, to name a few. In a hybrid OR, diagnostic imaging equipment like an MRI is located next to the OR and transferred into the room by the overhead track system to provide real-time images to the surgical team.

The advancement of monitor technology and its decreasing cost have brought the "wall of knowledge" concept into new OR rooms, as well. This is usually seen with an entire or large portion of a side wall dedicated to multiple HD flat screens showing live diagnostic images, patient medical history, vital signs, and the operation schedule to enhance communication and minimize errors during preparation and surgery.

Tapping into the 8.8 million pixels 4K format (ultra-high definition) of film technology, today's ORs allow surgeons to see tumors and anatomical areas of interest with four times the resolution of full HD-quality images using surgical endoscopes or cameras. Surgeon's tablets can also be connected to these amazing images during consultations with patients and family members.

Planning innovation
No matter how advanced an OR is, it can’t function on its own. It must be supported by a clean core, central sterile, and various storage and support spaces. New takes on how these areas are designed can ultimately result in streamlined operations and workflow.

For example, one hospital added a sterile equipment setup room between two ORs with the same air change rate and sterile environment as adjacent ORs. This allowed the OR to be prepared even before the earlier surgery was finished and helped reduce turn-around time. In another instance, a pass-through window was added between an OR and clean core, which reduced movement between these rooms and ultimately minimized unnecessary infection risk.

These kinds of features developed through Lean design exercises aren’t necessarily obvious at first, but reflect the latest thinking in OR designs of the future.

Considering the “Operating Room of the Future” revealed that today's ORs have come a long way from where they began a little more than 100 years ago. They’ve become larger, cleaner, and more wired than ever before.

The acceleration of the development of medical technology will continue to affect the surgical environment and pull it in directions that we can’t even imagine. Who knows if the future OR will ever look like the Hollywood version of ORs, but one thing is certain: It will not be a simple white box anymore.


Kwang Lee, AIA, LEED AP, is senior project manager at Tsoi/Kobus & Associates. He can be reached at