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Inside a modern Operating Room

An operating theater (also known as an Operating Room (OR), operating suite, operation suite, or Operation Theatre (OT)) is a facility within a hospital where surgical operations are carried out in an aseptic environment.

Historically, the term "operating theater" referred to a non-sterile, tiered theater or amphitheater in which students and other spectators could watch surgeons perform surgery. Contemporary operating rooms are usually devoid of a theater setting, making the term "operating theater" a misnomer in those cases.

Operating rooms

Operating rooms are spacious, in a cleanroom, and well-lit, typically with overhead surgical lights, and may have viewing screens and monitors. Operating rooms are generally windowless, though windows are becoming more prevalent in newly built theaters to provide clinical teams with natural light, and feature controlled temperature and humidity. Special air handlers filter the air and maintain a slightly elevated pressure. Electricity support has backup systems in case of a black-out. Rooms are supplied with wall suction, oxygen, and possibly other anesthetic gases. Key equipment consists of the operating table and the anesthesia cart. In addition, there are tables to set up instruments. There is storage space for common surgical supplies. There are containers for disposables. Outside the operating room, or sometimes integrated within, is a dedicated scrubbing area that is used by surgeons, anesthetists, ODPs (operating department practitioners), and nurses prior to surgery. An operating room will have a map to enable the terminal cleaner to realign the operating table and equipment to the desired layout during cleaning. Operating rooms are typically supported by an anaesthetic room, prep room, scrub and a dirty utility room.[1]

Several operating rooms are part of the operating suite that forms a distinct section within a health-care facility. Besides the operating rooms and their wash rooms, it contains rooms for personnel to change, wash, and rest, preparation and recovery rooms, storage and cleaning facilities, offices, dedicated corridors, and possibly other supportive units. In larger facilities, the operating suite is climate- and air-controlled, and separated from other departments so that only authorized personnel have access.

Temperature and surgical site infections (SSI). The current operating room design temperature is between 65 and 75 °F (18 and 24 °C).[2][3] Operating rooms are typically kept below 73.4 °F (23 °C) & room temperature is the most critical factor in influencing heat loss.[4] Surgeons wear multiple layers (surgical gowns, lead aprons) and may perspire into an incision if not kept cool; excessive heat may also decrease concentration and increase the frequency of errors.[4] Higher temperatures increased subjective physical demand and frustration of the surgical staff.[2] One option is to heat the patient to prevent surgical site infections (SSI) and keep the surgical team cool. There is a 3 fold increase in infection for every 1.9 degree Celsius body temperature decrease because of weakened immune response at lower body temperatures.[5] Radiation is the major cause of heat loss in patients, and convection (through air) is the second cause of heat loss.[6] In the first hour, it is common for a healthy patient’s temperature to decrease 0.5-1.5 °C as anesthesia causes rapid decrease in core temperature.[6] One study found that the most efficient method of maintaining normothermia included using warm wraps and a heating blanket (commercially known as a Bair Hugger).[citation needed] Additionally, pre-warming for thirty minutes may prevent hypothermia.[4]

Operating room equipment

Operating room lights are meant to suppress any shadow so that the surgeons have a deep light to use while doing procedures. The surgical light in the picture is the most revolutionary on the market. Thanks to double reflection technology, an improved version of indirect light, the lamp is able to give a light without any glare: the main cause of failure or error during procedures. Glare is the feeling of being blinded given by looking at the light source (the head lamp)
Operating room lights are meant so suppress any shadow so that the surgeos has a deep light to use while doing procedures. The surgical light in the picture is the most revolutionary on the market. Thanks to double reflection technology, an improved version of indirect light, the lamp is able to give a light without any glare: the main cause of failure or error during procedures. Glare is the feeling of being blinded given by looking at the light source (the head lamp)
Hybrid operating room for cardiovascular surgery at Gemelli Hospital in Rome

Surgeon and assistants' equipment

People in the operating room wear PPE (personal protective equipment) to help prevent bacteria from infecting the surgical incision. This PPE includes the following:

The surgeon may also wear special glasses that help him/her to see more clearly. The circulating nurse and anesthesiologist will not wear a gown in the OR because they are not a part of the sterile team. They must keep a distance of 12-16 inches from any sterile object, person, or field.


The Agnew Clinic, 1889, by Thomas Eakins, showing the tiered arrangement of observers watching the operation.
An operating room in the United States, c. 1960. Heart-Lung Machine with rotating disc oxygenator

Early operating theaters in an educational setting had raised tables or chairs at the center for performing operations surrounded by steep tiers of standing stalls for students and other spectators to observe the case in progress. The surgeons wore street clothes with an apron to protect them from blood stains, and they operated bare-handed with unsterilized instruments and supplies.[citation needed]

The University of Padua houses the oldest surviving permanent anatomical theatre in Europe, dating from 1595, it was used as an anatomical lecture hall where professors operated only on corpses.

The University of Padua began teaching medicine in 1222. It played a leading role in the identification and treatment of diseases and ailments, specializing in autopsies and the inner workings of the body.[11] In 1884 German surgeon Gustav Neuber implemented a comprehensive set of restrictions to ensure sterilization and aseptic operating conditions through the use of gowns, caps, and shoe covers, all of which were cleansed in his newly invented autoclave.[12][13] In 1885 he designed and built a private hospital in the woods where the walls, floors and hands, arms and faces of staff were washed with mercuric chloride, instruments were made with flat surfaces and the shelving was easy-to-clean glass. Neuber also introduced separate operating theaters for infected and uninfected patients and the use of heated and filtered air in the theater to eliminate germs.[14] In 1890 surgical gloves were introduced to the practice of medicine by William Halsted.[15] Aseptic surgery was pioneered in the United States by Charles McBurney.[16]

Surviving operating theaters

See also: Anatomical theatre

Old Operating Theatre in London

The oldest surviving operating theater is thought to be the 1804 operating theater of the Pennsylvania Hospital in Philadelphia.[17] The 1821 Ether Dome of the Massachusetts General Hospital is still in use as a lecture hall. Another surviving operating theater is the Old Operating Theatre in London.[18] Built in 1822, it is now a museum of surgical history. The Anatomical Theater at the University of Padua, in Italy, inside Palazzo Bo was constructed and used as a lecture hall for medical students who observed the dissection of corpses, not surgical operations. It was commissioned by the anatomist Girolamo Fabrizio d'Acquapendente in 1595.[19]

See also


  1. ^ "Operating Theatres | ModuleCo | Manufactured for Life". ModuleCo. Retrieved 2021-06-10.
  2. ^ a b Hakim, Mumin; Walia, Hina; Dellinger, Heather L.; Balaban, Onur; Saadat, Haleh; Kirschner, Richard E.; Tobias, Joseph D.; Raman, Vidya T. (2018-04-06). "The Effect of Operating Room Temperature on the Performance of Clinical and Cognitive Tasks". Pediatric Quality & Safety. 3 (2): e069. doi:10.1097/pq9.0000000000000069. ISSN 2472-0054. PMC 6132757. PMID 30280125.
  3. ^ ANSI/ASHRAE/ASHE Addendum h to Standard 170-2008. (2011). Ventilation of Health Care Facilities. Retrieved from
  4. ^ a b c Hart, Stuart R.; Bordes, Brianne; Hart, Jennifer; Corsino, Daniel; Harmon, Donald (2011). "Unintended Perioperative Hypothermia". The Ochsner Journal. 11 (3): 259–270. ISSN 1524-5012. PMC 3179201. PMID 21960760.
  5. ^ Reynolds, Luke; Beckmann, James; Kurz, Andrea (December 2008). "Perioperative complications of hypothermia". Best Practice & Research. Clinical Anaesthesiology. 22 (4): 645–657. doi:10.1016/j.bpa.2008.07.005. ISSN 1521-6896. PMID 19137808.
  6. ^ a b Rosenberger, Laura H.; Politano, Amani D.; Sawyer, Robert G. (June 2011). "The Surgical Care Improvement Project and Prevention of Post-Operative Infection, Including Surgical Site Infection". Surgical Infections. 12 (3): 163–168. doi:10.1089/sur.2010.083. ISSN 1096-2964. PMC 4702424. PMID 21767148.
  7. ^ a b c d e f g h i j k "Operating Room Equipment: The Complete Guide | Knowledge Center". Retrieved 2022-01-19.
  8. ^ Carroll, Gregory T.; Kirschman, David L. (2022). "A Peripherally Located Air Recirculation Device Containing an Activated Carbon Filter Reduces VOC Levels in a Simulated Operating Room". ACS Omega. 7 (50): 46640–46645. doi:10.1021/acsomega.2c05570. PMC 9774396. PMID 36570243.
  9. ^ Carroll, Gregory T.; Kirschman, David L. (2023). "Catalytic Surgical Smoke Filtration Unit Reduces Formaldehyde Levels in a Simulated Operating Room Environment". ACS Chemical Health & Safety. 30: 21–28. doi:10.1021/acs.chas.2c00071. S2CID 255047115.
  10. ^ "Benefits of Using Disposable Shoe Covers". Amazon. Retrieved 2022-04-22.
  11. ^ Jerome J. Bylebyl, "The School of Padua: humanistic medicine in the 16th century," in Charles Webster, ed., Health, Medicine and Mortality in the Sixteenth Century (1979) ch10
  12. ^ Deysine, M (2003). Hernia infections: pathophysiology, diagnosis, treatment, prevention. Informa Health Care. pp. 13. ISBN 0-8247-4612-0.
  13. ^ "Surgeons and surgical spaces". Science Museum. Retrieved 2022-01-19.
  14. ^ Bishop, WJ (1995). The Early history of surgery. Barnes & Noble. pp. 169. ISBN 1-56619-798-8.
  15. ^ Porter, R (2001). The Cambridge illustrated history of medicine. Cambridge University Press. pp. 376. ISBN 0-521-00252-4.
  16. ^ Gross, E (1990). This day in American history. Verlag für die Deutsche Wirtschaft. pp. 61. ISBN 1-55570-046-2.
  17. ^ "Pennsylvania Hospital History: Virtual Tour - Surgical Amphitheatre".
  18. ^ "The Old Operating Theatre". The Old Operating Theatre Museum & Herb Garret. Retrieved 2022-01-19.
  19. ^ "Palazzo Bo and Anatomical Theatre | Università di Padova". Retrieved 2022-01-19.