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Electricity: How Much for the Contemporary Tertiary Care Operating Room? A Case Report

Shamir, Micha Y. MD; Weissman, Charles MD

doi: 10.1213/XAA.0000000000000842
Case Reports

Surgery requires many electrically driven devices. Three events occurred recently in an operating room (OR) suite circa the 1980s wherein circuit breakers tripped due to overloaded circuits. This led to us to (1) increase OR electric capacity; (2) record each instrument’s power requirements, map their OR location, and determine when during surgery they were used; (3) provide users with instruction and diagrams into which outlet to plug each instrument. When introducing surgeries requiring devices, especially with high electrical power (current or amperage) demands, or renovating older or planning new ORs, it is important to provide ORs with sufficient electric current, circuits, and outlets.

From the Department of Anesthesiology and Critical Care Medicine, Hadassah-Hebrew University Medical Center, Hebrew University-Hadassah School of Medicine, Jerusalem, Israel.

Accepted for publication May 31, 2018.

Funding: None.

The authors declare no conflicts of interest.

Address correspondence to Charles Weissman, MD, Department of Anesthesiology and Critical Care Medicine, Hadassah-University Hospital, Kiryat Hadassah, P.O. Box 12000, Jerusalem 91120, Israel. Address e-mail to

Surgical procedures have become increasingly “hi-tech” involving many pieces of electronic equipment. No longer is an appendectomy performed with a scalpel, a few clamps, some sutures, and electrocautery. Instead, it is performed endoscopically, with a high-powered light source, high-definition television camera, insufflators, and “harmonic” scalpel. Furthermore, the obligate accoutrements of the modern operating room (OR) include electrosurgery units, computers, anesthesia machines, endoscopy towers, infusion pumps, physiologic monitors, and ubiquitous smartphone chargers. What all these devices need is an adequate and reliable supply of electricity. Yet, many ORs, even those built a few decades ago, were not designed for such a glut of electricity-hungry devices.

A series of power outages, none which affected patient outcome, alerted us to this situation. These outages occurred within a 4-month period in 2015 during complex surgeries in a tertiary care medical center’s OR suite circa the early 1980s.

In Israel, as per the requirement of the Israel Ministry of Health (Regulation E-01) all hospitals have 3 types of 220 V, 50–60 Hz electric power circuits: (1) those supplied only by the electric power utility (white outlets); (2) those backed up by central generators with a 10- to 20-second or longer lag time (red outlets, “the emergency power system”); and (3) unlike the United States, an uninterrupted power supply (UPS) system where there is a central bank of batteries that provide “transition” power until the central generators are fully able to generate the electric load (blue outlets, “the UPS system”). In Israeli ORs, the electric power supply is provided exclusively by emergency and UPS circuits. Each electric supply (emergency and UPS) is required to have its own separate isolated power system (transformer, alarms, etc).

In each of the ORs, circa the early 1980s, there are 2 isolated power systems: a 10 ampere (2.2 kVA [kilo-volt-ampere] = [current {amperes} × V {volts}]/1000; 2.2 kVA = [10 amps × 220 V]/1000) UPS system (central battery backup followed by backup from the central emergency generators) for life support equipment, such as anesthesia machines, monitors, and infusion pumps; and a 19 ampere (4.2 kVA) emergency power (backup only by the central emergency generators) system for non–life-supporting equipment.

On hospital admission, the patients signed a form permitting their medical information to be used for medical educational and statistical purposes.

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  1. During liver transplantation, the circulating nurse plugged a surgeon’s headlight into a UPS outlet on the anesthesiologist’s utility boom causing a circuit breaker to trip. The physiologic monitor, anesthesia ventilator monitor, echocardiograph, and cell saver stopped working. The anesthesia machine ventilator and syringe pumps continued functioning with their backup batteries. The patient was manually ventilated and a battery-operated portable monitor used until the circuit breaker was reset.
  2. During another liver transplant, a slush ice machine was plugged into an emergency power outlet being used by a heater/cooler unit (part of a veno-veno bypass system) causing a circuit breaker to trip.
  3. During surgery for widespread peritoneal malignancy involving extensive peritoneal excisional surgery (including liver and omental resections) plus peritoneal lavage with heated chemotherapy (hyperthermic intraperitoneal chemotherapy), an emergency power supply circuit breaker tripped when a hyperthermia perfusion machine (Hyperthermia Pump, Belmont Instrument Corp, Billerica, MA) was turned on.

The first 2 events occurred in the same OR while the third event occurred in a different one. These ORs were constructed in the early 1980s. It is important to note that these events occurred after more than 100 liver transplants and extensive peritoneal excision plus peritoneal lavage with heated chemotherapy surgeries had been performed in the same ORs.

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In response to these 3 events, an inventory of the electricity-requiring equipment used for liver transplantation and hyperthermic intraperitoneal chemotherapy plus extensive surgery1 was made (Table 1). For each device, the manufacturer’s electric current (ampere) rating was recorded and the total amperes tallied to determine the absolute (gross) total power requirements, while use patterns for each device were mapped to determine which tended to be used simultaneously. Location of instruments within the OR and to which outlets they were connected helped determine the potential electricity load on each individual circuit.

Table 1.

Table 1.

Liver transplant surgery required between 24 and 27 devices using electric power (Table 1). The absolute total power requirement (maximal amperage draw) was 109 amperes (220 V). However, some instruments were not set to operate maximally (eg, warming blanket), only operated intermittently (eg, OR table) or for a specific time period (eg, ice slush machine). The maximal amperage draw of an instrument or heating source often occurs for only a second or 2 when the device is switched on. However, multiple devices are not all turned on at the same time so that the maximal electric power draw does not occur. Devices that cool, heat, or light had the greatest power demand (ice slush machine, rapid fluid/blood infuser, blood/fluid warmer). Although many operated intermittently, all had the potential to overload circuits, as happened with the slush machine. Most problematic was the veno-veno bypass equipment, a heater/cooler unit (16 amps), and a centrifugal blood pump (3 amps). Alternately, there were many devices that draw relatively small amounts of electricity, but their combined electricity demands were significant.

During the heated peritoneal infusion surgery, the absolute power requirements (maximal amperage draw) were 50–55 amps (Table 1). The hyperthermia perfusion pump drew the most power at 7.2 amps. However, it was used when other high-draw instruments, for example, electrosurgical unit and harmonic scalpel, were generally not in use.

After analyzing the electrical demands, the electricity supply to the ORs where these procedures were performed was increased. The 10 ampere (2.2 kVA) isolation transformers of the UPS system were upgraded to 19 amperes (4.2 kVA) and the 19 ampere isolation transformers of the emergency power system were replaced with 29 amperes (6.4 kVA) transformers, increasing the power supply from 29 to 48 amperes (10.6 kVA). Fortunately, the wiring gauge was able to safely accommodate the increased loads. This upgrade was accompanied by mapping the location of each instrument in the OR and designating into which electric outlet it was to be plugged. This was followed by an educational program for the anesthesiology and nursing staffs. In the two and one-half years since the upgrade and subsequent move to new ORs plus the attention paid to prevent circuit overloading, electric outages have not reoccurred while performing multiple (>40) liver transplants and extensive peritoneal excision plus peritoneal lavage with heated chemotherapy surgeries.

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This report illustrates some patient safety issues that can occur during complex surgeries requiring simultaneous use of many electrical devices. It points out that older ORs might have insufficient electric power to satisfy demand during complex surgeries, such as liver transplantation. Therefore, it is necessary to avoid overloading both individual electric circuits and the OR’s overall electrical capacity. If overload is a possibility, it may be possible to increase overall and circuit capacity (amperage), if the infrastructure (eg, wiring, transformers) permits. If this is impossible using existing infrastructure, the entire electrical infrastructure must undergo upgrading.

Analyzing OR electrical demands should be a routine part of the planning procedure when introducing highly complex surgeries and when planning renovations or new construction. First, it is necessary to examine the maximal power demand expected by the various operations/procedures performed or planned for the ORs. All the electrical equipment needed for the specific operation and their power requirements should be listed. Furthermore, the various phases of the surgery should be examined to determine when each device will be in use, whether it will be used intermittently or continuously, and whether it will be used at full power. Second, the location of each instrument within the room should be mapped to help determine the numbers and placement of electric outlets, the number of circuits required, and their capacity (amperage). In existing ORs, outlets might have to be moved or added. It is necessary to provide sufficient circuits so that failure of any 1 circuit will not affect too many life support devices. The distance from the device to the outlet should be minimized and electric cords should not touch the floor and become a tripping hazard nor should they interfere with the circulation of personnel within the OR. Boom mounting of electrical outlets should be considered. Third, with the ever-increasing electricity requirements, additional (“spare”) electric capacity and circuits should be provided for future needs. The issue of whether to include traditional generator-backed emergency power plus UPS or isolated power versus ground-fault interrupters should be based on local regulations. Moreover, it is important to take into consideration the responses to various types of electric power losses in the OR when planning or renovating2 (Table 2).

Table 2.

Table 2.

In a recently opened OR suite, the lessons of the above incidents have resulted in an enhanced electric supply, 20 amperes (4.4 kVA) of UPS power, and 40 amperes (8.8 kVA) of emergency power for a total of 60 amperes (13.2 kVA), double the capacity of the ORs built in the 1980s. In addition, separate 32-ampere (7.0 kVA) circuits are provided in each room for devices such as the heater/cooler used by perfusionists and high-powered lasers. A renovation of the old ORs that are to be used mainly for ambulatory and less complex surgeries is slated to increase UPS to 15 amperes and emergency power to 25–30 amperes, increasing electric capacity from 29 to 40–45 amperes per room.

In conclusion, increasing demands for electricity during surgery make it vital for hospital technical and clinical staffs to consider the demand for electricity, the location within the OR of various instruments, and the number and locations of individual circuits and outlets. Interestingly, there is little written about how much electricity is needed per OR. The 2014 National Electrical Code (517.30) calls for a minimum of 36 receptacles per OR. The recommendation is for at least 9–20 amp (110 V, 2.2 kVA per circuit) circuits with 4 receptacles per circuit, plus additional circuits for radiology equipment and lasers. These are in addition to the electric requirements for clocks, surgical lights, and room illumination. The code states that at least 12 of the 36 receptacles must be connected to the critical system (emergency power) or the normal system branch circuit. Additionally, all Life Safety and Critical branch outlets must “have an illuminated face or an indicator light to indicate there is power to the receptacle” (2014 NEC CMP-15-Art. 517; NFPA-99-Healthcare Facilities Code. 2018 National Fire Protection Association, Quincy, MA). The US Army Health Facility Design Technical Manual from 1990 called for 24 simplex outlets each 20 amperes 125 V (2.5 kVA) plus one 60 amperes 250 V (15 kVA) outlet for radiology equipment.11 Although the doubling of electrical capacity in our newly constructed ORs might seem excessive, it is important to note that what was considered adequate 35 years ago has become insufficient, especially for complex surgeries. Therefore, it is prudent to quantify the gross and net power requirements of equipment currently used in intensive surgeries such as cardiac procedures, liver transplantation, major vascular, complex abdominal, and complicated neurosurgical operations. Once these requirements have been quantified, “spare” power should be installed to cover future eventualities, including the introduction of new equipment, which if designed to heat, cool, or illuminate, can have significant effects on OR electricity requirements. Failure to pay attention to these realities could lead to power outages that could harm patients.

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Name: Micha Y. Shamir, MD.

Contribution: This author helped write and edit the manuscript.

Name: Charles Weissman, MD.

Contribution: This author helped write, edit, and revise the manuscript.

This manuscript was handled by: Mark C. Phillips, MD.

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The authors acknowledge the assistance of Mr Ori Goldstein and Mr Nachum Lipshitz and the members of the Hadassah Maintenance and Biomedical Engineering Departments for their assistance in preparing this manuscript.

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