Operation Room Hazards
Operation Room Hazards
A hazard is a situation that poses a level of threat to life, health, property, or environment. Most hazards are dormant or potential, with only a theoretical risk of harm; however, once a hazard becomes active, it can create an emergency situation. A hazard does not exist when it is not happening. A hazardous situation that has come to pass is called an incident.
Anesthesia and surgery are conducted in technologically intense environments that are always potentially hazardous. The most common hazards in operating room include fires and explosion, static electricity, electrical hazards, radiation injury, air pollution and power failure.
Fires and Explosions
Both of these can cause death or injury to the patient in the theatre. A fire can only occur if we have three things: spark or a hot surface, flammable substance and source of oxygen
Sources of sparks or heat
- Static electricity
- Faulty electrical switches and apparatus, e.g. saws, plaster cutters and drills
- Foreign matter, e.g. dirt or grease in the oxygen or nitrous oxide cylinders
- Open flames.
Flammable substances: Includes ether, ethyl chloride and solution in sprits. The addition of oxygen increased flammability.
Electricity is present in the atmosphere. A static electric charge occurs if two materials which conduct electricity poorly are brought into contact and then separated. If there is friction or movement between the two, a spark is produced and a spark, of course, can produce an explosion. Examples of non-conductors which can spark if they touch each other include plastic, woolen fabrics, non-conducting rubber, and synthetic materials such as nylon.
These should always be avoided in the operating theatre, using special conducting rubber instead. This rubber has graphite impregnated in it. It is black and has a yellow coding (either a yellow line or a stamp) to show it is antistatic.
Other precautions which can be taken to reduce the incidence of static electricity
- The floors in the operating room should have a conductivity of the same order as the other items resting on them. Concrete or conductive rubber or plastic, placed on existing floors tend to give the desired conductivity.
- Clothing- If in the operating room, don't wear clothing that could acquire a static charge. Avoid wool, plastic and nylon fabrics and wear cotton or other anti-static outer clothes instead. Wear aprons of conductive rubber. Wear anti-static boots or conductive canvas overshoes.
- Maintain a minimum relative humidity of 60% in the operating room. Static sparks are more frequent when the air is dry.
- Ventilation- Anesthetic gases are heavier than air and tend to collect at ground level. Air within one foot of the ground is the most dangerous. Fresh air should enter at the top and stale air should be drawn out at the bottom. For the same reason switches should not be placed close to the ground.
- Electric switches and electric apparatus should be inspected regularly by the electrician.
- Firefighting equipment should always be available outside the operating theatre.
- Smoking and open flames must be forbidden in the operating room.
There are electrical hazards associated with the operating theatre and similar situations where anesthesia is used. They may occur when patients are:
- Connected to or in contact with faulty electrically-operated medical equipment
- Accidentally connected to electric circuits by spillage of blood or saline into equipment being used
- Dependent on electrical equipment to replace or support vital organ functions
- Exposed to fire or explosions
- Undergoing treatment when safe levels of electrical energy are exceeded.
Additional care in keeping patients away from these hazards is needed when they are unattended or unconscious.Electric Shock
This occurs when the body actually becomes part of an electrical circuit with significant current flowing in it. Wiring defects, faulty equipment components and deteriorated insulation all allow abnormally high currents to flow in otherwise safe systems. Lack of maintenance and misuse are the usual causes. Individual susceptibility is variable and extra care is needed if the patient is strapped to the equipment or is unconscious.
Macroshock is the most common form and occurs when the body conducts an electric current which does not pass directly through the heart. It varies in intensity from mild sensory stimulation at 5 to 10 milliamperes (mA), becoming more painful as the current increases. At 50 to 60mA muscular contraction occurs and as the current increases towards 100mA the victim cannot release his grip and breathing becomes extremely difficult. Somewhere above this level of current respiratory paralysis, cardiac arrest and severe burning occur.
Microshock may occur when very tiny currents, such as 100μA, are intentionally or otherwise passed directly through the heart muscle; e.g. direct cardiac catheterization, measurement of cardiac output, etc.
High Frequency Currents i.e. alternating currents (AC) above 50 hertz are less likely to produce electric shock but can cause burns and interference with other devices such as pacemakers.
Direct Current (DC) is less likely to cause ventricular fibrillation than high frequency alternating currents (above 50Hz) but can cause a more pronounced skeletal muscle contraction. DC passing through any body tissue for more than very short periods can cause injury by electrolysis.
Nerve damage often occurs in electric shock especially with high currents. The spinal cord may be injured by large currents passing from head to foot or from arm to arm.Electrical Burns and Electrically Initiated Burns
There are three types of electrical burn injury:
- Carbonization of skin (from burns at very high temperatures of 1,000°C)
- Flame burns
- Direct heating of tissues by electric current producing coagulation and necrosis at entry and exit points and associated injury in muscle and blood vessels etc. through which current passes. The associated injury occurs at some distance from the body surface and results in much greater tissue destruction than is apparent at first inspection.
Note that patients suffering impaired circulation and prolonged contact may be burnt under conditions which would not hurt a healthy person, while those insensitive to pain or under anesthesia may not realize that they are being burnt.
Electrosurgical Units e.g. diathermy are arranged so that current from the active electrode flows through the patient and back to the generator via the dispersive cable. . For example, with a broken dispersive cable, the current may return via ECG electrodes. Electric blankets have large surface areas but also many pressure points through which high current levels may pass, generating heat. Don't use electric blankets in conjunction with electro-surgery. Use a water blanket instead.
Some other electrical burn hazards include:
- Poor sitting of return electrode. It should be near the operation site and where sufficient soft tissue provides a large contact area.
- Damaged leads, electrodes, etc.
- Skin preparation materials may impair the function of the skin as a return electrode region. If these preparations are flammable they may ignite.
- Electrically initiated burns may occur when patient heating pads, lamps, humidifiers etc. are used to excess.
- Unintentional overheating or overcooling of blood before or during transfusion may damage the blood or even result in cardiac arrest.
Air Pollution in the Operating Theatre
It is not surprising that in places where the air is highly polluted, certain medical conditions occur more frequently than they do in places where the air is cleaner. Three of those conditions are spontaneous miscarriage, congenital abnormalities and liver disorders. It is especially important, then, that in a hospital, particularly in a hospital operating theatre, we provide the cleanest air possible for patients and particularly for staff. The patients spend only a short time in the operating theatre whereas the nursing and medical staffs spend many hours each day in this atmosphere and are at risk for health problems.
Sources of air pollution are waste anesthetic gases which escape from:
- Faulty valves
- The ventilator
- Poorly fitted components in the breathing circuit
- Spilt anesthetic drugs
- Expired gases from the spill valve of the anesthetic breathing system
- Gases exhaled by the patient after anesthesia.
This pollution can be reduced by
- Regular thorough inspection of all anesthetic equipment
- Employing anesthetic techniques which limit or avoid the use of inhalational gases and agents e.g., circle system, total intravenous anesthesia and regional techniques
- An efficient scavenging system.
Critical areas employing electrically driven equipment such as some respirators (Ventilators) and dialysis machines require standby equipment (i.e. generators) to deal with this emergency.