Interventional Services

Surgeryand the interventional platform
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Frank Zilm,D.Arch, FAIA, Jeff Pinkham, MS
Surgery

F
or centuries surgery has provided relief from disease, corrections to anatomical and musculoskeletal problems, and a method to improve the physical quality of life. With the introduction of interventional imaging and other “minimally invasive” procedures, the term frequently applied to the facilities associated with these services is the interventional platform. These services are among the highest tech
nological areas of healthcare, requiring sophisticated skills and knowledge along with complex and expensive instrumentation. These services also represent one of the most “profitable” areas of a hospital, frequently resulting in high priority capital allocations and high political clout by surgeons and other medical staff.

Two seminal events have elevated surgery from a grim, high risk attempt to save lives into a sophisticated tool in the management of disease and injuries (trauma) to the body: the evolution of an
esthetic agents, and the development of germ theory.

Until the mid-nineteenth century surgeons had to be both knowledgeable and quick. Survival of the patient depended in part on prevention of death from physiological shock
related to the pain of the procedure. Many chose to die from medical conditions rather than experience the pain of surgery. Combined with the risk of infection, survival from surgery was, at best, problematic.

Archeological discoveries have uncovered evidence of early civilizations dating back to the time of Babylonia experimenting with herbal agents to relieve pain, typically derivatives of opium and cannabis. Other cultures, including Asian and Persian civilizations, develop oral compounds. Convergent events in the West set the base for modern anesthetics:
  • The discovery of ether and nitrous oxide
  • Experiments in the use of general anesthetics for dental procedures
  • Demonstration of the efficacy of anesthetics at Massachusetts General Hospital.

Introduction of AnesthesiaNitrous oxideand ether were first isolated and identified in Europe in the early nineteenth century. Early experimentation with these substances was a source of entertainment and amusement, particularly with the side effects of nitrous oxide (laughing gas). In the United Stated two dentists William Morton and John Warren grasp the potential medical benefits of ether and began utilizing the gas for dental extractions. In the fall of 1846 Morton demonstrated the administration of ether to physicians at Massachusetts General Hospital and in October 16 of that year the first surgical case using general anesthetics was performed at the hospital, setting the stage for the acceptance of this method for pain management. Since that time a variety of general and local anesthetic agents have been developed, reducing the risks associated with their application, the recovery time, and long term side effects. Depending upon the surgical procedure performed, anesthesiologist’s literally take a patient to the verge of death and then to recovery.

The second major force in shaping interventional procedures was the discovery of germ theory and the resulting development of sterile technique. Prior to the establishment of germ theory, surgeons would disregard the risks associated with soiled hands, clothes, and the purity of the air. In 1861 Louis Pasteur established the airborne transmission of microorganisms. He also demonstrated that boiling could kill these organisms, leading to the process now known as pasteurization.

It is estimated that during the mid-nineteenth century half of the patients having surgery died of post-surgical infections. Dr. Joseph Lister, an English surgeon, began soaking surgical dressings in carbolic acid, resulting in a dramatic decrease in infections. Despite resistance from the medical establishment (as with the previously cited Dr. Semmelweis), adoption of a number of techniques to control airborne and contact transmission of germs has evolved into what is referred to today as aseptic technique.

The provision of a clean operating room, clean air, sterile instruments, and a sterile work environment around a surgical site form the core of sterile technique. In no other area of a health care facility does the design of space have as significant an impact.

The contemporary surgery suite includes four major space components:
  • The operating room
  • Patient prep and holding areas
  • Post anesthesia recovery(PACU)
  • Supply and storage

Operating RoomThe total departmental gross square feet required to support one operating room is in the range of 2,700 -3,200 square feet. Determination of the required number of O.R.’s is function of the estimate operating rooms minutes, the time required to clean and set up for the next case (turn-around time), and the target occupancy:

Interventional Services - Health Architecture

In addition to the space within a surgery suite, the management and processing of surgical instruments has developed into a major space and equipment requirement, typically provided in an area call Central Sterile.

VCU Surgery
The size and design of an operating room is a function of the anticipated procedures, special equipment requirements and sterile techniques used to assure minimum risk of infections. Surgical infections can be very serious, particularly orthopedic infections that may not present symptoms until an advanced stage. Treatment for infections can be painful, costly, and in some cases require extreme actions, such as amputation. The nsf of an O.R. can range from 360 to over 1,000 square feet. There are at least two critical phases during a case which have design implications.

First is the set-up of a case, where nurses and other staff open sterile wrapped supplies and position instruments and equipment for the specific type of surgery. In order to maintain minimum risks of infections, the layout of the operating rooms must allow for circulation of staff without contact or inadvertent bumping into other staff or objects.
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Sterile FieldThe second critical phase is the execution of the surgical procedure. The ability to maintain a sterile field is a critical concept. The true sterile field includes the patient’s surgical site, the drapes around the site, the arms and chest of the surgeon, scrub nurse, and other assistants working directly over the open incision. The immediate area around this team, typically including trays with surgical instruments and other key equipment, is included in the sterile zone. This zone should be protected from non-sterile staff, supplies and equipment. Ceilings, walls, and floors must be designed with durable, cleanable surfaces, with minimum seams and crevasses.

During some surgical cases it is necessary to bring in portable x-rays and other equipment. Repositioning the patient may also be required. The size of the operating room should be analyzed to verify its ability to accommodate these events.

Air circulation in, and around the surgical site is as important as the size and layout of the operating rooms. Air particles larger than 0.3 microns can carry bacteria to a surgical site. Air flow into an operating room is typically filtered with HEPA(high-efficiency particulate air) filtration. Air flow into the room should allow for a unidirectional flow pattern, sometimes referred to as laminar air flow. The goal is to provide clean air over the site and to minimize air turbulence that could recirculate particles of skin or moisture from the surgical team.

The integration of imaging technologies, robotics, and other major pieces of equipment has created special room requirements. Among the newer combination of technologies is the integration of angiography CT and MRI into the operating room. Such rooms are frequently referred to as a Hybrid Operating Rooms. The space requirements for the Hybrid O.R. typically fall in the range of 800-1,000 nsf. A control room for the imaging equipment is also required.

Source SCS SystemsMRI’s introduced into the operating room environment, provide neurosurgeons and other specialties with “real time” information regarding location of tumors and other anatomical information during surgery. As discussed in the section on imaging, there are major safety issues.


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MRI Operating RoomHybrid Operating Room
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.Prep/recovery/PACU beds

Today most surgical procedures are performed as outpatient, or “same day” admits, meaning they arrive to surgery as outpatients, have their procedures and are then admitted. Patients are typically held for one hour or more prior to surgery in a prep room. It is critical to have sufficient bed capacity to meet the early morning demand, when most operating rooms are staffed.

After surgery, critical care patients are typically routed directly from the operating room to their critical care unit. Patients who have had a general anesthetic or patients who require observation are taken to the Post Anesthesia Recovery Unit (PACU). Patients will be in the PACU from one to six hours. Patients in the PACU are then moved to an inpatient unit, discharged, or moved to an observation area. Demand in the PACU area typically peaks around mid-day and then tapers off. If patients need additional observation they may go to a Phase II observation area or to an observation unit.



Organizational Concepts

A common organizational model for operating rooms in the United States is a “clean core” model. This wraps the operating rooms around a support core, where sterile supplies and backup instruments are quickly available. Patients, staff, and major equipment access the O.R.’s from a perimeter corridor.

Sterile Core Concept

Sterile CoreThis is a photo of a clean core area (Staff work area in the above diagram). It is considered one of the cleanest areas of the surgical suite. Back up sutures, emergency surgery set and other backup supplies are stored in this area.





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An alternative model incorporats interventional imaging procedure rooms and cardiac catheterization laboratory rooms adjacent to the O.R.’s. This provides opportunities for common prep and recovery areas and for long term flexibility. Operating rooms can be converted in interventional imaging room and vice versa.

Interventional O.R.


Instrument and supply management

The cost of supplies and the requirements for assuring sterile instruments presents a major operational demand on a surgery service. As previously noted, surgical infection presents one of the major risks in patient care. Assembling the correct set of instruments for a specific procedure requires staff that understands both sterilization methods and the specific mix of tools for a case.

To respond to these needs most hospitals have created a separate department, typically called Central Sterile(CS), or Sterile Processing and Distribution (SPD). As its name implies, CS is responsible for the sterile processing of instruments from all areas of the hospital. Typically surgery accounts for over 80 percent of the total volume, making the efficient flow between surgery and CS critical. In addition to managing instruments some departments will also take responsibility for cleaning other equipment items and in packaging other disposable sterile products for each case performed in surgery.

The typical CS service has four major functional areas:
  • Decontamination/Instrument washing
  • Prep and packaging
  • Terminal sterilization
  • Sterile storage, including cart assembly

Source: STERIS CorporationThe decontamination area receives soiled instruments from surgery, cleans gross tissue and material and places the instruments into tray where they pass through instrument washers. This area is separated by a wall from the rest of the central sterile area to minimize the possibility of airborne contamination.

In the clean work area instruments are inspected, assembled into trays and wrapped in linen or placed in special containers. At this point the instruments are placed in a steam sterilizer where they are exposed to high pressure steam sterilization designed to kill any living organism.[1] After terminal sterilization the instrument sets are either stored in CS (or Surgery), or placed back into use in the operating room. Most large surgery/CS systems have established a case cart system for movement of instruments and supplies. One or more carts are prepared for each surgical case. The cart contains the instrument sets, disposable supplies, linen, and other required equipment.

The total area required for a contemporary central sterile service is significant, and the cost of the sterilization equipment make the planning of this service a major planning issue. Although the flow of instruments between CS and surgery is critical, the location of CS on the same floor as surgery is unusual. A common model for the design of surgery/CS system is to place CS underneath surgery, connected by dedicated elevators. This arrangement also allows the resupply of Central Sterile from the materials management service of the hospital.


Sterile Core Process
Examples of Surgery Suite Layouts


Surgery Plans
Interventional Services - Health Architecture

[1] Some instruments cannot be steam sterilized, requiring special processing equipment, such as vaporized hydrogen peroxide sterilization machines.

For an excellent review of current and potential future trends in surgical robotics see Catherine Mohr's TED presentation: Surgery's Past, Present and Robotic Future.