Specialized Nursing - Essay Example

SPECIALIZED NURSING Name: Course: Professor: Institution: April 23, 2012. Introduction Magnetic resonance imaging (MRI) has become a very common and reliable way of diagnosing patients. Due to advance in technology and detailed information about the diagnosis in question, many people have relied on this procedure for the detailed and quality images. However it has not been without challenges and some of the challenges are the burns that result from these procedures. RF burn is damage caused to the skin or other tissues and they are mostly caused by ionizing radiation or exposure to energy from radio frequency. During medical imaging high exposure to X rays can result to these burns. Body cells are damaged by ionizing radiation when they interact as this result to damage. The body reacts to this and what results is an erythema (Diaz, et.al, 2010 pp 413). This is redness around the affected area. In most cases radio burns are associated to cancer because of the ability of ionizing radiation to cause damage to DNA thus making the cell cancerous. Radio frequency burns can be of first, second or third degree. Some of the burns are usually treated by plastic surgery. Causes Magnetic resonance imaging (MRI) is considered a safe diagnostic procedure. However excessive heating can result to injuries to the person who is undergoing the MR procedures. Some of the causes of these burns include: physiologic monitors, objects that are made from conductive materials, damaged coils and electronically activated devices. Heating of implants can sometimes be problematic if the devices are made from conductive materials whose shape is elongated or those that form loops with a certain diameter (ECRI Institute, 2008 pp 379). Excess MRI heating has been witnessed for particular types of catheters that have thermistors, guide wires, leads and also certain cervical fixation devices. The degree and nature of the health effects that result from overexposure to radio frequency is dependent on the intensity, frequency and exposure duration. The distance from the source of the radio frequency is also a determinant of the effect it causes. Shielding of these frequencies can also determine the effect they cause. One of the main effects of exposure to radio frequencies causes heating of body tissues because the body absorbs energy from the radio frequency fields. If a person is exposed to this kind of energy for long their body temperatures increases and they develop symptoms similar to those of somebody who have been involved in a physical exercise (Hardy & Weil, 2010 pp 607). In rare cases or even the body is exposed to other heat sources at the same time a person’s body system may find it hard to cool due to the heat load and this ends up to heat exhaustion or stroke (Haik, et al, 2009 pp 295). Heat of specific positions for long which is also known as localized heating can be disastrous as it result to damage of the internal tissues. Non uniform fields are responsible of forming hot spots due to refraction of the radio frequency fields within the body .This may also be caused by interaction between the radio frequency fields and the metallic implants in the body like aneurism clips and cardiac pace makers. Those body organs that have poor heat control are at a higher risk of damage resulting from heat .These organs include eye lens and the testes. Burns and shock result from flow of electric currents between the person and the conducting object when they are exposed to these fields (Jacob, et al.2010 pp 848). There have been laboratory researches that have identified very low heating that result to tissue heating. A research conducted in the United States, showed that most of the incidences resulting from excessive heating were not related to equipment problems or presence of a certain type of conductive material. A review conducted in the MAUDE database for a period of ten years showed that most of the thermal injuries were linked to MRI procedures. Most of the incidences include burns of first, second and third degrees (Johnston. et al, 2009 pp 149). Most of these cases showed that, the body parts of the patient were in direct contact with the RF coils of the MR systems. Other cases were suspected to have resulted from direct contact of skin to skin points.MR systems utilize RF pulses to create a signal. The energy is transmitted through space to the patient. Incase conducting materials are present in the RF field, there can be a concentration of electrical currents that can cause excessive heating and this may result to damage to the tissues surrounding. This is likely to happen because currents have the ability to induce two types of magnetic fields. These are the pulsed radio frequency field and pulsed magnetic gradient field. The two fields vary as time goes. In case the changing magnetic flux lines intercept there may be an occurrence of an electromotive force, or electrically conductive loop. When heating is done this is when current flow through the loop and its magnitude is determined by the resistance of the loop. For this reason it is only those equipments that have a well designed current path that should be used for MR procedures (Kainz, 2007 pp 450). In most of the MRI systems, currents induced by pulsed RF fields are one thousand times bigger than those than those induced by pulsed magnetic gradient field. The latter are produced by a coil of large gradient that encloses the RF coils. This includes also the surface coils that are smaller which are located near the body that is under diagnosis.FR burns are more likely to occur when the body that is being imaged is close to the RF coil. More so, the frequency and power of pulsed RF field increase with the strength of the magnetic field and this means that the burns are more likely when the magnetic field is high in the MR system. Certain shapes of coils can result to resonance which increases the propensity of the coil to concentrate RF currents. Currently, the operating frequencies, and conducting loops whose size is tens of centimeters can result to problems. This can be avoided if high techniques are applied to limit the current in RF. In addition, loops with small gaps that are separated by an insulator may also conduct current (Kanal, et al, 2007 pp 1450). Prevention In order to prevent possible and excessive burns in the MR procedures, certain precautions can be taken. First when preparing the patient ensures that there are no metallic objects that are unnecessary that are in contact with the patient’s body. These include thing s like, jewelry, key chains, etc. When preparing the patient for the MR procedure insulation material should be used. This helps to avoid points of skin to skin contact where closed loops form when there are touching body parts. In doing this appropriate padding can be used. An insulator should be put in between the skin of the patient and the transmit coil. This material should have the recommended thickness of one centimeter. Alternatively, the transmit coil can be padded (Mattei, 2007 pp 1640). The patient can be placed in a position where there is no direct contact of the patient’s body and the transmit RF coil. This can be achieved by letting the patient place their arms on the head, or using elbow pads between the patient’s body tissues and the RF coil. This is usually very much recommended for those examinations that use RF body coil or other large coil that transmit energy. Only those equipments which are electrically conductive like ECG leads and those that have been thoroughly tested and said to be safe that should be used for the MR procedures. Recommendations and criteria for specific MR safety should be followed for all implants that are made from electrically conductive materials. These include neurostimulator systems, cochlear implants, cardiac pacemakers and bone fusion stimulators. Before any use of electrical equipment, the integrity of the insulation and housing of components should be checked. These equipments include monitoring leads, wires, surface RF coils and cables. Any non-essential material that is electrically conductive should be removed. Examples of these include ECG leads, cables, unused surface RF coils, EEG leads and wires. Any electrically conductive material that is essential during the MR procedures and so cannot be removed should be kept away from the patient’s body by placing an insulator between the patient and the conductive material. Those materials that are electrically conductive and must be present in the MR procedures should be avoided from forming loops (Newcombe, et.al.2008 pp 163). One point to note is that, body tissues are conductive and so there is a chance of forming a conductive loop which may have a circular or U shape. When placing electrically conductive materials always prevent cross points. This is a point where cables cross one another, where it loops itself, or where it could be touching a patient or transmitter coil more than one time. The conductive materials should also be avoided from having close proximity with one another because transmit coils and cable can couple capacitively without necessarily being into contact with one another when they are placed together. When positioning the electrically conductive materials they should exit through the center of the MR system downwards. They should never exit along the sides of the system or even close to the RF coil. Electrically conductive materials should not be placed across an external metallic prosthesis. Examples include cervical fixation device or any other device that have a direct contact with the patient’s body. Operating of MR devices should be left to the trained personnel. This includes the monitoring equipment and other devices. Manufactures instructions and maintenance of electronic equipment in the MR environment should be strictly followed. In case equipment is detected to be not in good working condition during the MR procedure it should be immediately removed to minimize the chances of exposing the patient to a possibility of getting the RF burns. The person should be monitored closely during the MR procedure. In case a patient’s reports sensation of heating the MR procedure should be discontinued immediately and the situation should be assessed thoroughly. RF power level of deposition can become excessive if the RF surface coil results to decoupling failures. The operator recognizes such failures as concentric semicircles in the tissues of the Image associated to the MR. It can also be recognized as an unusual amount of an image which is not uniform in relation to the position of the transmit RF coil. Adopting these guidelines ensures that the safety of the patient is maintained especially because conductive materials and those devices that are electronically activated are used in association with the MR procedures. Before any imaging procedure ensure that the electrodes to be used have not passed their expiration date. There should be coordination between the MRI staff to ensure that the cables to be used are available and have been cleared for use during the MR procedure. The patient should be searched for any previous use of electrodes and cables that might have been left either in clothing or sheets .Any electrodes and cables that are not in use should immediately be removed. This reduces the possibilities of getting burns from left over electrodes. One important thing that should not be forgotten is that even when the cables and electrodes have been approved for use in the MRI environment burns can still occur. This is in cases where the skin is not in complete contact with the electrodes. This occurs when excess hair on the skin has not been removed or when there exists an air gap between the skin and the electrodes. In the presence of a gap electrical pathway is broken and heat builds up at the centre of the electrode. It also allows the current to arch to the skin from the electrode and this is what causes the burns. To avoid this, the cables should not be left to form a loop and should be kept away from the patient’s skin. This is done by putting a blanket under them. Once the MRI procedure is complete the patients should always be tested for possible burns or reddening of skin beneath the electrodes. This should be a common procedure that can be very helpful to those patients that cannot verbalize. Any patient that is diagnosed to have a burn should receive proper medical treatment. All the relevant medical information should be documented and filed in an incident report. The biomedical engineering department should be notified of the electrodes used plus any other that could be remaining. While using equipments for physiologic monitoring in the MR environment burns can be highly minimized if the correct procedure and guidelines of the equipments are followed. These guidelines include not looping the sensor cables, use of graphite electrodes and cables that have high resistance as well as placing the cable away from the radio frequency coil. Again a certain type of monitoring equipment can be used to eliminate the electrical conducting path. For instance monitors of end tidal CO2 may only need a plastic nasal on the patient and a plastic tube for the airway leading to the monitor. Another example is the measurements of a non invasive blood pressure that may only necessitate a plastic tube between the monitor and pressure cuff of the patient (Shellock, 2007 pp1183). Conclusion RF burn is damage caused to the skin or other tissues and they are mostly caused by ionizing radiation or exposure to energy from radio frequency. In most cases radio burns are associated to cancer because of the ability of ionizing radiation to cause damage to DNA thus making the cell cancerous. Some of the causes of these burns include: physiologic monitors, objects that are made from conductive materials, damaged coils and electronically activated devices. Heating of implants can sometimes be problematic if the devices are made from conductive materials whose shape is elongated or those that form loops with a certain diameter. This can be avoided if high techniques are applied to limit the current in RF. In addition, loops with small gaps that are separated by an insulator may also conduct current. In order to prevent possible and excessive burns in the MR procedures, certain precautions can be taken. First when preparing the patient ensures that there are no metallic objects that are unnecessary that are in contact with the patient’s body (Yamazaki, et.al.2008 pp 883). These include thing s like, jewelry, key chains, etc. When preparing the patient for the MR procedure insulation material should be used. Electrically conductive materials should not be placed across an external metallic prosthesis. Only those equipments which are electrically conductive like ECG leads and those that have been thoroughly tested and said to be safe that should be used for the MR procedures. Before any imaging procedure ensure that the electrodes to be used have not passed their expiration date. There should be coordination between the MRI staff to ensure that the cables to be used are available and have been cleared for use during the MR procedure. Bibliography: Diaz F, Tweardy L &Shellock FG (2010) Cervical fixation devices: MRI issues at 3-Tesla. Spine 35:411-5 ECRI Institute. Hazard report. (2008) Patients can be burned by damaged MRI AV entertainment systems. Health Devices. vol; 37:379-80 Haik J, Daniel S, et al. (2009). MRI induced fourth-degree burn in an extremity, leading to amputation. Burns. vol;35:294-6. Hardy PT 2nd, Weil KM. (2010) A reviews of thermal MR injuries. Radiol Technol. VOL;81: 606-9. Jacob ZC, et al. 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Comments on MRI heating tests of critical implants. Journal of Magnetic Resonance Imaging vol; 26:1182-1185. Yamazaki M, et al. (2008) Investigation of local heating caused by closed conducting loop at clinical MR imaging: Phantom study. Nippon Hoshasen Gijutsu Gakkai Zasshi.vol 20;64:883-885. Read More