Chapter 2. The Operating Room Environment

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  A pressure of 1000 psig indicates an E-cylinder that is approximately half full and represents 330 L of oxygen.
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  The only reliable way to determine residual volume of nitrous oxide is to weigh the cylinder.
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  To discourage incorrect cylinder attachments, cylinder manufacturers have adopted a pin index safety system.
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  A basic principle of radiation safety is to keep exposure “as low as reasonably practical” (ALARP). The principles of ALARP are protection from radiation exposure by the use of time, distance, and shielding.
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  The magnitude of a leakage current is normally imperceptible to touch (<1 mA, and well below the fibrillation threshold of 100 mA). If the current bypasses the high resistance offered by skin, however, and is applied directly to the heart (microshock), current as low as 100 μA may be fatal. The maximum leakage allowed in operating room equipment is 10 μA.
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  To reduce the chance of two coexisting faults, a line isolation monitor measures the potential for current flow from the isolated power supply to the ground. Basically, the line isolation monitor determines the degree of isolation between the two power wires and the ground and predicts the amount of current that could flow if a second short circuit were to develop.
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  Almost all surgical fires can be prevented. Unlike medical complications, fires are a product of simple physical and chemistry properties. Occurrence is guaranteed given the proper combination of factors but can be eliminated almost entirely by understanding the basic principles of fire risk.
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  Likely the most common risk factor for surgical fire relates to the open delivery of oxygen.
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  Administration of oxygen to concentrations of greater than 30% should be guided by clinical presentation of the patient and not solely by protocols or habits.
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  The sequence of stopping gas flow and removal of the endotracheal tube when fire occurs in the airway is not as important as ensuring that both actions are performed quickly.
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  Before beginning laser surgery, the laser device should be in the operating room, warning signs should be posted on the doors, and protective eyewear should be issued. The anesthesia provider should ensure that the warning signs and eyewear match the labeling on the laser device as laser protection is specific to the type of laser.

Anesthesiologists, who spend more time in operating rooms than any other group of physicians, are responsible for protecting patients and operating room personnel from a multitude of dangers during surgery. Some of these threats are unique to the operating room. As a result, the anesthesiologist may be responsible for ensuring proper functioning of the operating room’s medical gases, fire prevention and management, environmental factors (eg, temperature, humidity, ventilation, and noise), and electrical safety. The role of the anesthesiologist also may include coordination of or assistance with layout and design of surgical suites, including workflow enhancements. This chapter describes the major operating room features that are of special interest to anesthesiologists and the potential hazards associated with these systems.

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