Preface

The number of electrophysiological (EP) and interventional cardiology (IC) procedures performed throughout the world increases year after year. Regional scientific societies concerned with IC and EP exist to promote and maintain professional standards, including radioprotection standards (RP). The following guidelines represent the points of view of SOLACI’s Radiation Safety Commission and the Working Group on Interventional Cardiology of ISEMIR (Information System on Occupational Exposure in Medicine, Industry and Research), an initiative of the International Atomic Energy Agency (IAEA).

These documents are based on the Radioprotection Guidelines (RP) of the Cardiovascular and Interventional Radiology Society of Europe (CIRSE) and the Society of Interventional Radiology (SIR) [1]. There is significant common ground between IC and interventional radiology, and we are most grateful for their permission to partially reproduce these guidelines.

For abbreviation purposes, the terms interventional cardiologist and IC in these guidelines respectively include electrophysiologists and EP.

Introduction

The number of IC procedures performed throughout the world increases year after year (2). Due to the steady progress in technology and experience these procedures are performed in increasingly complex patients and in increasingly more difficult angiography situations. The benefits of IC to patients are both extensive and beyond dispute, but many of these procedures also have the potential to produce patient radiation doses high enough to cause radiation lesions and occupational doses to interventionalists high enough to cause concern (2-5). This guide is intended to offer information on RP and serve as orientation to minimize occupational radiation doses.

Radiation doses interventional cardiologists receive can vary by more than an order of magnitude for the same type of procedure and for similar patient dose (4). Recently, there has been particular concern regarding occupational dose to the crystalline of hemodynamics staff, including of course interventional cardiologists (3). New data from exposed human populations suggest that crystalline opacities, and severe opacity known as cataract, can occur after exposure to doses far lower than those previously assumed to cause cataracts (6,7). Available data is statistically consistent with the absence of a threshold dose but, if one exists, it should be lower than 0.1 Gy (8,9). Additionally, the latency period, the time for cataract formation, appears to be inversely related to radiation dose (6). More specifically, recent studies show a greater incidence of crystalline opacities among interventional cardiologists and hemodynamics nurses related to occupational exposure (10,11).

Occupational RP is a necessity whenever radiation is used in the practice of medicine, but it is especially important for fluoroscopy guided imaging procedures where doses tend to be higher. (4,12-14).

Occupational RP requires appropriate education and training for the interventional cardiologist and the availability of appropriate protection tools and equipment. In most countries, interventional cardiologists do not receive the kind of formal training interventional radiologists receive, therefore, alternative measures must be taken to give interventional cardiologists the appropriate education and training before they start performing IC procedures.

Occupational RP measures must be in accordance with the international standards and recommendations, as well as the national RP regulations. (15,16).

We must also be aware of the ergonomic detriment caused by personal RP lead equipment (17,18).

RP measures are necessary for all individuals working in a hemodynamics suite. This includes not only interventional cardiologists but also technicians and nurses, that spend long hours in the radiation environment, and other actors such as anesthesiologists and auxiliary staff only occasionally involved. They are all considered “occupationally exposed workers” (TOES, trabajadores ocupacionalmente expuestos) and are subject to the necessary RP requirements. (15,16). All staff working in a hemodynamics suite require adequate monitoring and access to RP tools and equipment. They must also receive adequate education and proper training to their jobs (15,16,19,20). What is more, training level should be risk-based.

These guidelines intend to offer a basic review of the medical physics relevant to RP and to provide advice and guidance to interventional cardiologists, nurses and technicians that perform interventional procedures.

Measurement of Occupational Exposure

Quantities and Units

Several international organizations have published recommendations on the quantities and units that should be used in occupational radiation dosimetry (19,21). National regulations provide specific requirements for personal dosimetry in interventional practice. Doses limits for workers are expressed in terms of effective dose (E) for whole body exposure and equivalent dose in an organ or tissue (HT) for exposure of part of the body. The unit for both quantities is the sievert (Sv) with its submultiples of common use: the milisievert (mSv) and the microsievert (μSv).

The equivalent dose and effective dose cannot be measured directly. They should be calculated from other, simpler quantities that can be measured with personal dosimeters (DP). The equivalent dose is the mean absorbed dose in a tissue or organ T multiplied by a radiation weighting factor, wR, that for diagnostic x-rays equals 1, so the absorbed dose and the equivalent dose are numerically equal. Effective dose (E) is the weighted sum of the equivalent doses in all specified tissues and organs of the body. These tissue weighting factors wT, are highest for red bone marrow, breasts, colon, lungs and stomach and lowest for the cortical bone, salivary glands, brain and skin (16).

A typical personal dosimetry provides 2 values: Hp (0,07) and Hp (10) that represent the dose equivalent in soft tissue at 0,07 and 10 mm below body surface where the dosimetry is located (16). Hp (10) is used to evaluate E and Hp (0,07) to evaluate equivalent doses in skin, hands and feet of operators. A dosimeter worn at neck level (for example over the thyroid protector) over the protective apron, provides a reasonable estimate of the dose delivered to the surface of the unshielded part of the body (skin and crystalline). If the dosimeter is worn on the anterior chest under the protective apron, the obtained value is assumed to be a good estimate of the operator’s effective dose and but it does not provide precise information about eye dose.

The formula used to estimate E from dosimeter data may be specified by national regulatory authorities or by the local hospital dosimetry department. Selecting the appropriate formula can be complicated in IC because of radioprotective equipment and because 2 dosimeters are normally used. Several algorithms have been published to estimate E from dosimeter data of one or more dosimeters (22,28). All estimates must take into account the location of dosimeters, the presence or absence of radioprotective equipment, and the precise dose readings.

Uncertainties in occupational dosimetry

Uncertainties in occupational dosimetry can present in three areas: inaccuracy of dosimetry itself, inaccuracy of the used algorithm, and uncertainty regarding the correct use of dosimeters.

Personal dosimeters in the interventional laboratory are exposed to a radiation field composed of radiation scattered back from patients and from the wearer’s body. Accuracy and precision are affected by factors that influence the amount of radiation reaching the dosimeter from these 2 sources compared to the calibration conditions. Additional inaccuracy derives from the different calibration conditions and the radiation used in an interventional laboratory, particularly because of the direction and energy of the x-ray beam. A report on dosimetric uncertainty providing full information on this aspect has recently been published (29).

All formulas used to estimate E from dosimeter readings are based on certain assumptions about the staff’s radioprotective garments. For safety reasons, most of the commonly used formulas overestimate the individual’s actual E dose. The various formulas and associated inaccuracies have been published (22.35). While a few formulas when applied to IC have underestimated E by more than a few percent or overestimated it by no more than 100%, other formulas may be much wrong. This emphasizes the need of a qualified expert to interpret personal dosimetry in the IC laboratory.

Inaccurate dosimetry results also arise from the inappropriate use of dosimeters. This includes wearing the dosimeter in the wrong location on the body, or wearing it part of the time over the apron and the rest of the time under the apron, or wearing it upside down, the rear part receiving direct radiation. On occasions, dosimeters may be left (when not being used) in a radiation exposed environment. Some professionals may even forget to wear their dosimeters or deliberately avoid wearing them part of the time. All of these actions result in an incorrect value for E and make it impossible to determine the user’s true occupational risk (29).

Another source of uncertainty may derive from the wrong choice of dosimeters, by choosing dosimeters habitually used to estimate effective E (entire body) when trying to estimate equivalent dose for hands, eye lens or legs. Depending on the location of dosimeters, this extrapolation may induce mistakes in estimated doses for organs or tissue.

Occupational Dosimetry in the Interventional Laboratory

Dosimeter Use

All occupational exposed workers must be monitored to determine their level of exposure. This allows adequate identification of wrong working habits leading to high personal exposure that can be reduced with some practical advice. Monthly measurement of occupational exposure is recommended.

The International Commission on Radiological Protection (ICRP) recommends that operators wear 2 dosimeters: one over the lead apron, at thyroid level, and another under the apron, at chest or abdomen level. In some cases, such as EEF procedures, left hand monitoring is recommended for the first operators (37).

For pregnant occupational exposed workers that have declared pregnancy, fetal doses can be estimated using a dosimeter placed under the protective apron, on the mother’s abdomen. The mean dose normally overestimates actual fetal dose because radiation attenuation by the mother’s tissues is not considered. This dosimeter should be evaluated on a monthly basis. Electronic dosimeters can be used to obtain a quick estimation in these cases (38). In those centers that regularly employ 2 dosimeters, workers that may get pregnant are recommended to wear dosimeters under their protective garments at waist level. The readings obtained allow an estimation of fetal dose since conception to pregnancy declaration.

Dose limits

Dose limits for occupational exposures are expressed in equivalent doses for deterministic effects in specific tissues or organs and E for stochastic effects throughout the body.

Dose limits for occupational exposure recommended by ICRP have been adopted by most of the countries in the world, though the limits are described slightly differently in some countries (16,39).

The International Basic Safety Standards establish these dose limits as a requirement (15).

Table 1. Limits for occupational exposure adapted from ICRP (16).

* A mean calculated over 1 cm² of the most radiated areas of the skin

Additional restrictions apply to the occupational exposure of pregnant women. For women who may be pregnant, the ICPR recommends that the standard of protection for the fetus should be broadly comparable to that provided to members of the general public (16). After a worker has declared her pregnancy, working conditions should ensure that the additional dose to the embryo/fetus does not exceed about 1mSv during the remainder of the pregnancy. It is recommended to inform pregnant workers about the dose a fetus can receive (40). Requirements on declaring or not declaring pregnancy must comply with national regulations, since there are countries that allow not to declare it.

The current limit for the annual equivalent dose to crystalline is 150 mSv. This limit is under review by an ICRP task group and it could be reduced soon since it is considered high (6-9). The annual limit for the hands is 500 mSv. These doses can be estimated by placing a personal dosimeter on or near the tissue of interest, for example, on the thyroid protector to estimate eye dose or a ring dosimeter for the hands, and this is valid for all cases where the x-ray tube is mounted under the patient table. However, a dosimeter placed on the thyroid protector does not reflect the eye dose if the operator is wearing protective lead glasses.

It is not possible to estimate the exact dose of the operator’s hands using body dosimeters because of the proximity of the hands to the x-ray beam and to the scattered radiation. A ring dosimeter is recommended to estimate the accurate dose of hands when indicated (37).

Risk Estimates

Effective dose (E) is intended to be proportional to the risk of radiation-induced cancer. The ICRP refers to the highest permissible doses as E limits (Table 1) and intends to limit the risk of stochastic effects to a reasonable level, for example, to set the limit beyond which doses (and therefore, risks) are considered unacceptable. National regulatory authorities require the implementation of optimization principles and, as a result, they could expect occupational doses to be considerable lower than the dose limits. Interventional cardiologists are inevitably exposed in the performance of their duties. However, a busy interventionist who takes all appropriate radiation safety precautions is unlikely to have an E exceeding 10 mSv/y, and is more likely to receive 1 to 4 mSv/y (4,41-51).

The risk to specific organs such as the fingers or the crystalline is related to the dose delivered to these tissues. The limit dose for these organs and tissues (Table 1) has been established for the prevention of radiation effects and occupational exposure to levels below deterministic effects of radiation. As already been mentioned, the eye dose is under review.

Evaluation of personal dosimetry data

Personal dose records

The information contained in a dose record will vary depending on the number, type and location of personal dosimeters used. This record will contain information on the effective dose E, assessed from the readings of 1 or 2 dosimeters worn on the chest or abdomen under and/or over the lead apron, and may contain information on the equivalent dose to the crystalline from the dosimeter worn over the thyroid protector, and the equivalent dose to the hand from a ring or bracelet dosimeter.

Dose reports must be sent to the invasive cardiology department by the dosimetry service provider as soon as possible after each evaluation period. Results must be available for all occupational exposed workers. Relevant information of dosimetry reports of each professional includes the dose for the current period and the current year.

Surveillance of occupational dose

The facility’s Radiation Safety or Medical Physics Service should review the personal dose records of individual workers regularly. This review ensures that dose limits are not exceeded. It also evaluated whether the dose level is the expected for each room and for each worker’s particular duties. Workers’ recorded dose levels should be compared to their past dose levels and to the average dose levels of others doing similar work at the same facility or at other facilities. Standard staff dose readings for different types of procedures have been published (4,14,37,42-5,47,50-57). Depending on the type of procedure and the technique used, the operator dose, per procedure ranges from 5 to 500 Sv at thyroid level (with maximum values when a screen hanging from the ceiling is not used) and <0.1 to 50 Sv at the waist or chest under the apron and from 50 to more than 2000 Sv on the hands. Unfortunately, these doses correspond, as we said, to data stated in terms of dose per procedure and first operators and there is not much information on second operators, nurses or technicians. Translating these data to monthly or annual worker information is difficult, particularly seeing the wide range of potential doses for each type of procedure. As noted above, the E for an interventional cardiologist is typically 1-4 mSv/y.

Investigation of high occupational dose

Every hospital has to look into individual dose levels based on the expected dose for each worker. The World Health Organization recommends investigation when monthly exposure of a worker reaches 0.5 mSv for E, 5 mSv for dose to the crystalline or 15 mSv for the hands or extremities, or the average mean of these values (12,58). In this case, the radiation safety officer or a medical physicist should contact the worker directly to determine the cause of the unusual dose and to make suggestions about how to keep the worker’s dose as low as reasonably achievable (ALARA criteria).

Expected readings for occupational exposed workers in a hemodynamics suite (as well as other interventional laboratories) are expected to be higher than those of other hospital workers. Using the same investigation criteria for all workers leads to non productive investigations of interventionists, and often to their reduced compliance with monitor use. Therefore, it is crucial to investigate occupational doses with regard of the particular nature of each role.

Investigation of a high personal dose value begins with a check of the validity of the dosimeter reading. Invalid dosimeter readings include wearing designated under protective apron dosimeters over the apron, wearing a different worker’s dosimeter and dosimeter storage in a location where it is exposed to radiation. In these cases, next month’s dose must be strictly monitored to make sure they were correctly used and stored, the worker must be asked to inform of any work habit that may have caused this increased dose, or of any new techniques or of overtime. Equipment setting changes should also be investigated. In this case, contacting the technical support of x-ray equipment is always of use. In all cases, once the problem is solve, dose levels should return to usual levels during the next monitoring period, when workload returns to normal. If the problem is not temporary or if the cause for the increase in radiation is not found, the worker must be observed in its daily practice paying special attention to behavior: proximity to patient, use or not of radioprotective equipment and use of equipment settings. On occasions, an external observer with the right knowledge can point out unrecognized habits.

Another possibility in this case is to use an electronic dosimeter to observe real time radiation dose levels, which can help avoid a situation that would cause high risk exposure (59). With adequate attention to dose reduction techniques, in general it is not necessary to limit workload, as long as compliance with radiation limits is ensured.

Radiation Protection Tools

The greatest source of radiation exposure to the operator is scatter from the patient. Generally, controlling patient dose also reduces scatter and limits operator dose. However, the adequate use of radiation protection tools reduces scatter even more without impending the procedure or jeopardizing the patient’s safety.

Shielding

There are three types of shielding: architectural shielding, equipment mounted shields and personal protective devices. Architectural shielding is built into the walls of the procedure room or rests wheels, on the floor, and is particularly well suited for nurses, anesthesiologists, etc.

Equipment mounted shielding (or support elements) includes protective drapes suspended from the ceiling and from the table, between the under-table x-ray tube and the operator; they have been shown to protect operator and staff from patient radiation and to reduce operator dose. Unfortunately, they sometimes cannot be used if the x-ray grantry (C-arm) is in a steep oblique or lateral position.

Ceiling suspended leaded shields, generally constructed of acrylic or leaded glass, and should always be used. Properly placed shields have been shown to dramatically reduce operator eye dose (61,62). It now appears that the threshold dose for cataract formation can be reached within several years for a moderately busy practitioner, so suspended shields or leaded eye protectors, or both, should always be used by anyone performing interventional procedures on a regular basis (3). Crystalline injuries have been reported in both operators and staff when ceiling suspended shields were not used for complex interventional procedures. (63). Some rooms have more than one protector shield, or similar device, for complex procedures, for example, those that need operators on both sides of the table or that involve other workers that also need protection.

Disposable, protective patient drapes are now available, These contain metallic elements (bismuth or tungsten-antimony) and are placed on the patient once prepared and dressed for the procedure (64,65). They have been shown to reduce scatter substantially with reported reductions of 12-fold for the eyes, 26 fold for the thyroid and 29 fold for the hands (65). They are costly and therefore not widely employed but they can be reserved for complex procedures involving high exposure, as long as it does not interfere with the procedure.

Personal Protective Devices

Personal elements include aprons, thyroid shields, eyewear and gloves. The first 2 must always be worn and eyewear as well, although if the suspended shield is used conscientiously and in all cases, they may not be strictly necessary. As regards aprons, the vest/skirt configuration is preferred by many operators in order to reduce the risk of musculoskeletal injury, since it distributes weight in shoulders and waist (66). These are typically 0.25 mm lead (or equivalent), so that when worn they provide 0.50 mm lead-equivalent anterior protection, where they cross over. Operators and staff who work in the interventional laboratory on a regular basis should be provided with properly fitted aprons, both to reduce ergonomic hazards and to provide optimal radiation protection. (67). All aprons should be periodically inspected for fissures and other faults (faulty seams) that may need fixing or replacing. Wear and tear can be examined with fluoroscopy.

There are devices that attempt to reduce the fatigue and injury associated with wearing heavy protective apparel, for example, one of them involves a rolling device from which the apron is hung. The operator stands behind the apron and rolls it at convenience (69). They can also travel on a set of ceiling mounted rails and allow the operator to move between patients’ head and feet within seconds (70). These devices are not of wide-spread use since they are uncomfortable to wear; patient is too far and they call for improved ergonomics.

Since the 150 mSv/y occupational limit for eye exposure currently recommended by ICRP may be too high, and since radiation cataract formation may be a stochastic effect, operators are strongly advised to use shielding suspended from the ceiling. Leaded eyeglasses are an alternative to ceiling-suspended shields for this purpose. Leaded eyeglasses with large lenses and protective side shields provide more protection than eyeglasses without these features. They help to minimize scatter which approaches the operator from the side and scatter from the operator’s own head (71). The main disadvantage of leaded eyeglasses is their weight on the nose. These glasses can be ordered with the pertinent prescription (from an ophthalmologist) or can be ordered in a bigger size to wear them over regular prescription glasses. The use of these glasses is recommended throughout procedure (3,16).

In general, the operator’s hands should be kept out of the primary radiation beam. Surgical leaded gloves (that allow catheter handling) are not always recommended because they give a false sense of protection, which is really low (reducing around 50%). When leaded disposable gloves are used, additional environmental exposure must be considered (because of lead). En any case, hands must never be directly exposed to the x-ray beam, even when protective gloves are worn (also in this cases there is a false sense of protection) [72]

Effectiveness of shielding

Radioprotection personal apparel have evolved from heavy 1mm of lead shielding to lighter composite (lead plus other high atomic-numbered elements) or entirely lead free materials that typically provide 0.25 to 0.5 mm lead equivalent protection. All radioprotection gear must be properly labeled with lead-equivalent protection percentage. However, lead-equivalence of lead free aprons should be interpreted carefully, since it depends on x-ray quality and the method used to determine the equivalence (for example, wide or narrow radiation beam, etc) (68,73-5). In these situations, a medical physicist should be consulted. Transmission of x ray beams through protective aprons depends on its lead-equivalence, its composite and radiation beam energy. For example, transmission of 70 to 100 kVp x-rays through 0.25 mm lead-equivalent or a lead free composite was in the environment 4 to 20% while through one of 0.50 mm was between 0.6 and 7% (68). These values can be compared to the transmission of 70-100 kVp through a 0.25 mm pure lead apron (5-15%) or through 0.5 mm (0.5-5%) [68].

Efficacy of leaded glasses depends on 2 factors: scattered radiation from head and the presence or absence of side protection. Leaded glasses reduce the dose to the operator’s eye from frontal exposure by a factor of approximately 8 to 10 and when side exposure is included, the protection factor is decreased to between 2 and 3 (although these factors depend mostly of glass model) [76,77]. Another factor to be taken into account is the direction the interventionist is looking while using x-rays. For example, if his eyes are fixed in a high point, scatter radiation may penetrate directly in the eyes, passing below the glasses.

When radioprotection shielding is adequate, leaded gear, shields and drapes, aprons and glasses, scatter radiation to the operator is substantially lower. This should be the rule, rather than the exception.

Scatter

It is defined as radiation that “bounces” against patients or operators and detailed discussion of scatter isodose curves is beyond the scope of this document. The magnitude and distribution of scattered radiation is affected by many factors, including patient size, gantry angulation, patient position, filtration, fluoroscopic settings (direct beam kV, collimation) and the use of shielding. (3,78-82). Overall, in a unshielded environment, and for a posteroanterior projection, the exposure is greatest below the table, most at the operator’s waist level and least at the eye level. However, substantial operator eye doses can be reached in unfavorable circumstances, for example, when working with large patients, high dose fluoroscopy, left projection and gantry angulation. With pediatric patients when the interventionist needs to get closer, the radiation required is lower since there is less volume to irradiate. Nevertheless, scatter dose to the eyes can be high if radioprotective gear is not properly used (83).

Practical advice to reduce or minimize occupational radiation dose

A fundamental principle states that decreasing patient dose will result in a proportional decrease in scatter dose to the operator and staff. Therefore, techniques that reduce patient dose will generally also reduce your occupational dose (“win-win” situation). Below you will find a list of recommendations later described with more detail.
Table 2: Key Recommendations for the Safe Practice of IC.

1) Minimize fluoroscopy time: Fluoroscopy should be used only to observe objects or structures in motion. Review the last image hold or use previous ones for study, consultation or education instead of additional fluoroscopic exposure. Use short taps of fluoroscopy instead of continuous operation. Fluoroscopy to determine or adjust collimator blade positioning can be eliminated by using the virtual collimation feature, when present.

2) Minimize the number of fluoroscopic images. Remember imaging irradiates in average some 10 to 20 times more both for patient dose and scatter. The total number of images depends on the duration of procedure the series number and the frame rate selected. The number of frames and frame rate has to be the lowest possible needed to obtain the desired clinical objective. Radiographical equipment in general offers a range of frames/sec and selection depends on clinical needs. As a general rule, the lower number of frames/sec, the lower the patient dose. However, the quality of images should be taken into account. For example, is your equipment has good quality images at 15 frames/sec, use this option instead of 25 or 30 frames/sec. A medical physicist can be consulted for advice on the interrelation between dose and image quality, and your equipment options.

3) Use available patient dose reduction technologies. These include low fluoroscopy dose rate settings, low frame rate pulsed fluoroscopy, removal of the anti-scatter grid, spectral beam filtration and use of increased x-ray beam energy. The latter 2 are part of equipment configuration while the first can be selected. Since some of the terms can be confusing, a medical physicist should be consulted to obtain the greatest possible advantage of your equipment. You may remove the anti-scatter grid in children and some small, which reduces dose at the cost of somewhat decreased image quality. Remember to move the table so that the area of interest is in the x ray beam before pressing the radioscopic pedal and not the other way round.

4) Use good imaging chain geometry. Position the patient support to raise the table as high as possible (if you don’t need it to be at the isocenter) so that the patient’s back is as far as possible from the x-ray tube. Place the image receptor as close as possible to the patient’s chest. This geometry (tube far from patient and intensifier or image receptor closet to the patient’s chest) should be the one in side projections. Try to avoid extreme angulations, since they require high rate doses.

5) Collimation and filtration. Adjust collimator blades tightly to the area of interest since this will significantly reduce patient’s dose and scatter radiation considerably improving image quality, and reducing occupational dose (“win-win” situation). If available, use virtual collimation. You should also use semitransparent filters that improve image quality and reduces patient dose and scatter radiation.

6) Position yourself in a low scatter radiation area. Depending on your role in the intervention suite, there are several ways to place yourself in a low scatter area. Stay as far away from the x-ray beam as possible. Remember radiation reduces at the square distance, which means that if we duplicate our distance to the patient, our radiation will be 25% lower. Therefore, when shooting “step back” and always behind a shield. Never place your hands in the x-ray beam. Use a power injector for contrast when feasible. Remember angulated projections radiate more both the patient and the operator (there is more scatter). Extreme angulated projections irradiate more from the side than from the x-ray beam, which means an antero-brain oblique projection is the one that most irradiates the operator.

7) Wear protection shielding at all times. Wear all personal radioprotection elements available: the thyroid protector, the leaded apron (if it is a 2 piece with harness it may reduce weight on shoulders and distribute it on the heaps) ceiling suspended shields can provide significant additional dose reduction, especially to unprotected areas of your head and eyes. If this device covers enough surface, you could do without leaded glasses, but if not, you must wear them (with good side coverage and protection). Under table leaded drapes reduce lower extremity and bismute fields or similar also help reduce occupational dose.

8) Use appropriate fluoroscopic imaging equipment. Remember that using fluoroscopy equipment under suboptimal conditions frequently results in increased radiation dose. You should carry out a control service program to ensure optimal conditions and coordinate actions with the Medical Physics department at your facility. Interventional procedures should be carried out with equipments designed for this purpose. High radiation dose procedures should be performed with the recommended dose reduction technology, complying with the most current international Electrotechnical Commission standards (84). Encourage your institution to purchase this kind of equipment for interventional laboratories. Portable or mobile equipment for IC do not have the same power and are not robust enough or safe enough as regards radioprotection for patients and workers. They should only be used in laboratories with low workload and for simple procedures.

9) Use equipment subject to quality assurance. It is important that you are familiar with equipment features at the time of purchase to be able to maximize possibilities and protocols. This way, image quality, patient dose and occupational dose will be the appropriate. Quality assurance is an essential component of any long time monitoring program.

10)  Obtain appropriate training. You and all staff involved in the procedure should have a general knowledge of safe operating practices in a radiation environment and your hospital should provide it. Formal training, mandatory in many countries, is recommended.(85) If this was not possible, alternative training is recommended before interventionists start performing IC procedures, to assure the adequate RP. IAEA (International Agency of Atomic Energy) offers expert advice and training material for interventionists in their website at: http://rpop.iaea.org/RPOP/RPoP/Content/AdditionalResources/Training/1_TrainingMaterial/Cardiology.htm.

You and all staff involved in IC procedures should have a general knowledge of the safe practices in an ionizing radiation environment. You should be thoroughly familiar with the operation of the particular fluoroscopy equipment you are using.

11) Wear your dosimeter(s) and know your own dose. Always wear your dosimeter (2 preferably, one at chest level and one over the thyroid protector) and know your occupational monthly dose. If you notice irregular readings despite your routine or your workload have not varied, you should consult with the medical physicist. Know your dose. Your dose data will not be accurate unless you always wear your dosimeters and wear them correctly

12) Monitor radioprotection equipment periodically. Leaded aprons and other radioprotection equipment should be revised regularly and replaced when damaged. Protective aprons should be examined fluoroscopically and inspected visually for damage and defects every year.

Management Responsibilities

Management should provide an adequate level of human and material resources to ensure that radiation dose is adequately controlled. Typically, a radioprotection program (RPP) should be implemented to guarantee rules and regulations compliance across the different structures, to apply the pertinent policies and see organizational procedures through (15,58). All hospitals with hemodynamic suites should carry out a radioprotection program, which includes, but is not limited to, assigning responsibilities for occupational and patient radioprotection and the general safety of all individuals in the organization, establishing rules and guidelines for interventional cardiologists and the rest of staff, providing radioprotection equipment and the correct dosimetry, and implementing an education and training radioprotection program. As an example, an effective RPP reduces occupational dose in half to the first operator in EP and IC procedures (48,86).

Quality assurance is an essential component of any personal dosimetry program (15,36,58,87). Occupational doses should be analyzed by each department and high doses and outliers should be investigated. Standardized methods for acceptance and testing of protective aprons are needed, due to the wide variation in actual attenuation values of aprons (68, 75).

Adequate and relevant training programs should be provided for all levels of occupational exposed workers within the organization, including management, to develop a commitment to radiological protection, so that all involved actors can contribute to the reduction and control of exposure (15,58,87-89).


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Introduction

Selecting the appropriate vascular access is often key to the success of all endovascular diagnostic or therapeutic procedures. Familiarity with the different vascular sites available, [and] insertion site selection, use and management are essential to the interventional cardioangiologist. Each percutaneous vascular access approach (femoral, brachial, radial, popliteal, etc.) requires specialized training. Although some management aspects of vascular access are common to all sites, specific issues (compression, administration of heparin, nitroglycerin, or intravascular verapamil) are particular to each site.

Presently, the femoral artery remains the most common arterial percutaneous access site. However, the radial artery approach is rapidly gaining acceptance, especially for obese patients, to shorten the observation period postintervention and to facilitate an interventional ambulatory strategy. (1)

Site selection for each patient will take into account different factors, with special regard to:

1) Vascular peripheral disease symptoms or indicators
2) Vascular access problems or complications in previous procedures
3) Inability to lie supine for prolonged time
4) Known aortoiliac disease or previous aortobifemoral bypass
5) Use of devices that involve the insertion of larger sheath sizes 
6) [Suitability] and compatibility of vascular access materials with blood vessel tortuosity.

We also admit that, in contrast with other aspects of our specialty area, access site selection is more a matter of tradition, [personal] opinion and experience than a decision based on evidence.

These guidelines state consensus-based recommendations made by the authors. They focus on each vascular approach [to interventional procedures] (Class I, II, III) and the evidence level they are based on.

1) The Retrograde Femoral Approach

In contrast with the direct humeral technique, the preferred access in the early days of cardiac catheterization, retrograde femoral access via needle puncture avoids open artery and/or vein surgery to introduce catheter with either diagnostic and/or therapeutical purposes.(2)

[The femoral approach firstly] identifies the femoral artery with strongest pulse. Puncture is made 1 to 3 centimeters below the crural arch, which runs from the anterior superior iliac spine to the pubic tubercle. The femoral artery lies in the center of the arch and can be felt several centimeters below it. Occasionally, in cases where pulse is not a reliable landmark, fluoroscopy guided puncture can be [indicated]. Normally, the common femoral artery can be punctured in the medial third of the femoral head (3). Most of [vascular] access problems (and vascular complications) derive from poor assessment prior to puncture.

Class I Recommendations:

1) For diagnostic and therapeutic procedures in coronary territory (Evidence Level C).
2) Fist choice access for interventions in aortoiliac territory (mainly primitive iliac and first part of external iliac) (Evidence Level C).
3) To treat most of renal artery lesions (Evidence Level C.)
4) For diagnostic and therapeutic procedures in supra aortic vessels (Evidence Level C).

Class IIa Recommendations:

Class IIb Recommendations:

1) Morbid Obesity: it can significantly complicate puncture. To avoid complications at puncture site anatomical and morphology thorough assessment is decisive. (Evidence Level C).
2) Large postoperative scarring: not only complicates puncture and catheter introduction but also makes post intervention compression harder (Evidence Level C).
3) Previous aortoiliac disease or presence of femoropopliteal bypass (when treating this pathology in not the objective [of intervention]) (Evidence Level C).
4) [Significant] iliofemoral tortuosity (Evidence Level C)
5) Severe lumbo-sacral pain: the necessary 6 to 8 hours rest after femoral access can severely aggravate preexisting pain in these patients. (Evidence Level C).
6) Coagulopathies: presence of coagulation pathology can alter coagulation times and therefore increase the risk of complications, especially hematomas at puncture sites. (Evidence Level C).
7) Chronic oral anticoagulation (Evidence Level C).

Class III recommendation:

1) Femoral pulse completely absent.

2) The Antegrade Femoral Approach

The antegrade approach is preferred by some authors, especially interventional radiologists, for a more direct access to some medial and distal femoropopliteal territory and infrapopliteal trunks, [and it] can be extremely useful to cross severely calcified lesions (4). However, puncture is sometimes difficult and involves potential complications (retroperitoneal hematoma).

Class I Recommendation:

1) To treat tibiopernoeal territory lesions. (Evidence Level C).

Class IIa Recommendation:

1) As an alternative to contralateral femoral access in medial third and superficial distal femoral lesions and popliteal artery lesions (Evidence Level C).

Class III Recommendation:

1) In obese patients when no anatomical constraints can be identified.

3) The Contralateral Femoral Approach (cross-over).

This technique is suitable for femoropopliteal interventions as well as distal external iliac interventions when no ipsilateral approach is possible. (4).

Compared to the antegrade approach, it is technically easier and is associated with a lower complications incidence.

Another advantage of the contralateral femoral access to reach femoropopliteal territory is that the compression bandage to secure haemostasis is applied to the leg that was not intervened. Therefore, the recanalized segment will not be affected by proximal compression, which can reduce early thrombotic reclusion rates (5).

Class I Recommendations:

1) To treat the very distal external iliac artery lesions and very proximal lesions of the femoral artery (Evidence Level C).
2) To treat femoropopliteal territory lesions. (Evidence Level C)

4) The Bilateral Retrograde Femoral Approach

Class I Recommendations:

1) For percutaneous treatment of aortoiliac bifurcation lesions and infrarenal abdominal aorta lesions. It requires bilateral femoral access since double balloon techniques are often preferred (Evidence Level C).

5) The Popliteal Approach

In approximately 30% of superficial femoral artery total occlusion cases, the attempt to recanalize via contralateral or antegrade femoral access fails. Given these circumstances, the popliteal approach is a viable alternative with good immediate results (6). Only patients with permeable proximal popliteal and permeable distal superficial femoral arteries and adequate distal run-off are can be considered for this approach. The incidence of complications at puncture site is greater than that of conventional access sites, probably as a consequence of the anatomical situation of the popliteal artery and the lack of specific training.

Class IIb Recommendations:

1) In the hands of experienced operators, as an alternative to total recanalization of occlusions of the superficial femoral artery, after a frustrated attempt via other access sites. (Evidence Level C).

6) The Radial Approach

Vascular access complications have been common since the early days of coronary interventionism, when Melvin Judkins developed the femoral via as preferred access. The reduced dimensions of [the new] devices has significantly minimized vascular complications, though they still occur with an incidence that can reach 8%, as described by Chroussat et al in interventions done with glycoprotein inhibitors IIbIIIa.(7)

Faced to high rates of vascular access complications and considering the intense anticoagulation protocols interventional procedures involved, Lucien Campeau, from the Montreal Heart Institute, pioneered radial catheterization in 1989(8). He promoted the radial artery approach based on its anatomical advantages: the double flow in the hand, absence of nerves in the neighboring areas, easy haemostasis, and the fact that vessel occlusion does not result in mayor complications.

The referred study proves the safety and efficiency of radial access in 100 patients. Canadian and Dutch interventional groups have contributed to advance this technique, led by Kiemenij, who in August 1992 performed the first coronary angioplasty via transradial access in the Hemodynamics Department of OLVG in Amsterdam. (9)

The ACCESS study (10) randomized a total 900 patients approached in 3 different [techniques]: radial, brachial or femoral. Results proved vascular complications in 7 patients (2.3%) of the brachial group, 6 (2.0%) of the femoral and none (0%) of the transradial group. (p = 0,035).

A remarkable study was published by Agostoni et al (11), who carried out a systematic review of radial vs. femoral randomized studies. This study finally identified 14 eligible trials. 2 of them were invalid because information was incomplete, or because, upon request, the authors refused to provide the missing information. A total 3224 patients were randomized, 1668 for radial and 1556 for femoral. 3 of the studies reported novice operators, 3 reported operators with some experience and the rest reported operators well familiar with the selected approach. It is worth noticing that one of the key elements of radial access is the operator’s expertise beyond the learning curve. (12) Hence, 3 of the studies compared a well experienced procedure (femoral) to another that was still in its early stages (radial).

No significant differences in clinical major events were reported; therefore, events were not [a direct result of selected technique]. However, data associated to vascular complications favored radial access (0.3 vs. 2.8%; OR 3.30 95% IC 1.63 a 6.71; p <0.001).

It is worth mentioning that hospital postoperative care favored the radial approach (1.8 vs. 2.4 days, p<0,001). Hospital costs data, gathered in 5 studies for a total 853 patients, were lower for the radial group (p<0,001).
Pre procedure recommendations:

Class IIb (Evidence Level C):
1) Remove [jewelry].
2) Insert lines in contralateral arm.
3) Administrate previous sedation and analgesia (Fentanyl, Midazolam).
4) Infiltrate 1cc Lidocaine

Recommendations according to operators’ experience:

Operators in the learning curve. Class IIa recommendation (Evidence level C).
1) Stable patients

Trained operators. Class IIa recommendations (Evidence level C).
1) Stable patients.
2) Acute coronary syndrome.

Recommendations for radial spasm management (Evidence level C):
1) Administrate intraarterial verapamil (IIa recommendation).
2) Administrate intraarterial nitroglycerin (IIb recommendation).
3) Use hydraulic lines and low-French catheters (IIb recommendation). 

Class III recommendations for radial approach (Evidence level C):
1) Patients with Tromboangiitis obliterans and chronic arterial occlusions distal to the wrist.
2) Patients with a negative Allen’s Test.
3) Raynaud disease.
4) Only available arm for arteriovenous hemodialylsis fistula.

7) The Brachial Approach 
The brachial approach is an alternative vascular access technique frequently used for diagnostic procedures, particularly in case of severe iliac obstruction (13). Puncture is performed in the distal segment of the brachial artery, above the antecubital fossa. At this level, the artery is relatively superficial and can be compressed against the humerus for haemostasis after sheath removal.

Class I Recommendations: (Evidence Level C)
1) Diagnostic procedures in supra-aortic vessels, renal arteries, digestive and peripheral, in case of bilateral iliac obstruction, aortic infrarenal obstruction or extreme elongation and tortuosity of iliac arteries and abdominal aorta.
2) Diagnostic coronary procedures in the same circumstances as above mentioned and in patients with radial access contraindications.
3) Renal ATP or superior mesenteric artery procedures in patients with extremely angulated offtakes of the abdominal aorta.

Class II Recommendations: (Evidence Level C)
1) Therapeutical procedures in supra aortic vessels in case of bilateral iliac obstruction, infrarenal aortic obstruction or extreme elongation and tortuosity or iliac artery and abdominal aorta.
2) Coronary therapeutical procedures, in the same circumstances as the above and in patients with contraindicated radial access.

Class III Recommendations: (Evidence Level C)
1) Absent brachial pulse.
2) In obese patients, where no flat bone support for compression can be clearly identified.

8) Vascular Closure Devises

These devices were created as an alternative to manual compression after coronary percutaneous intervention. They have the potential advantage to reduce haemostasis time, facilitate patient mobilization, shorten the postoperative hospitalization period and increment patient satisfaction. However, the published literature is not significant: it focuses on the ambulatory period and evaluates several devices and different generations of devices in the same study.

On the other hand, vascular complications are rare when manual compression is performed by a dedicated team, and this particular aspect of safety is controversial with regard to closure devices. (14-15)

This is why it is difficult to define recommendations based on consistent evidence. Additional studies are required to properly assess safety of these devices and the impact of more recent generations of these products in patient care.

Class IIb Recommendations:

1) In the context of therapeutic procedures, of the 3 most evaluated devices in the literature, AngioSeal, showed a tendency to fewer complications than manual compression. Perclose did not show benefits, compared to manual compression, and with VasoSeal, complications rates associated to vascular access were greater than with manual compression. (Evidence Level A).

Class III Recommendations:

1) In the context of diagnostic catheterization, neither of the arterial closure devices offers a significative lower complications rate of arterial access sites compared to manual compression. (Evidence Level A).

2) For patients with diffuse femoral arteriosclerosis or focal stenosis less than 2 cm away from puncture site. (Evidence Level C).

3) For patients with preexistent vascular complications or vascular conditions found during procedure (Evidence Level C).

4) In -4 mm diameter arteries (Evidence Level C).

5) When puncture site is too close to femoral bifurcation (Evidence Level C).

Bibliography

1. Bashore TH, Bates ER, Berger PB, et al. ACC/SCAI Clinical Expert Consensus Document on cardiac catheterization laboratory standards. J Am Coll Cardiol 2001; 37:2170-21.

2. Grossman W, Baim D,. Cateterismo, angiografía, e intervención cardíaca. 4º edición. 1992. Editorial Intermédica.

3. Rupp SB, Vogelzang RL, Nemcek AA, et al. Relationship of the inguinal ligament to pelvic radiographic landmarks: Anatomic correlation and its role in femoral angiography. J Vasc Intervent Radiol 1993;4:409-413.

4. Biamino G, Scheinert D. Access sites for peripheral interventions. Euro PCR2004 Course Book: 330-335.

5. Jorgensen B, Meisner S, Holstein P, et al. Early rethrombois in femoro-popliteal occlusions treated with percutaneous transluminal angioplasty. Eur J Vasc Surg 1990;4:149-152.

6. Zaitoun R, Iyer SS, Lewin RF, Dorros G. Percutaneous popliteal approach for angioplasty of superficial femoral artery occlusions. Catheter Cardiovasc Diag 1990;21:154-158.

7. Chroussat M, et al. Vascular complications and clinical outcomes after coronary angioplasty with IIbIIIa receptor blockade. Eur Heart J 2000;21:662-667.

8. Campeau L, et al. Percutaneous radial artery approach for coronary angiography. Catheter Cardiovasc Diag 1989;16:3-7. 9. Kiemeneij F, et al. Percutaneous transradial artery approach for coronary stent implantation. Cathet Cardiovasc Diagn. 1993;30:173-8. 

9. Kiemeneij F, et al. Percutaneous transradial artery approach for coronary stent implantation. Cathet Cardiovasc Diagn. 1993;30:173-8. 

10. Kiemeneij F, Laarman GJ, Odekerken D, et al. A randomized comparison of percutaneous transluminal coronary angioplasty by the radial, brachial and femoral approaches: The Access study. J Am Coll Cardiol 1997;29:1269-75.

11. Agostoni P, Biondi G, De Bendictis M, et al. Radial versus femoral approach for percutaneous coronary diagnostic and interventional procedures. J Am Coll Cardiol. 2004;44:349-56. 

12. Goldberg SL, Rensio R, Sinow R, et al. Learning curve in the use of the radial artery as vascular access for PTCA. Cathet Cardiovasc Diag 1998;44:147-152.

13. Hildick-Smith D, et al. Coronary angiography in the presence of peripheral vascular disease: Femoral or brachial/radial approach?. Catheter Cardiovasc Diag 2000;49:32-37.

14. Koreny M, Riedmuller E, Nikfardjam M, et al. Arterial puncture closing devices compared with standard manual compression after cardiac catheterization. JAMA 2004;291:350-357.

15. Nikolsky E, Mehran R, Halkin A, et al. Vascular complications associated with arteriotomy closure devices in patients undergoing percutaneous coronary procedures. A meta-analysis. J Am Coll Cardiol 2004;44:1200-9.

Overview

Contrast media used in interventional cardiology are iodinated compounds that can roughly be classified as ionic and nonionic, depending on whether they can dissociate in a solution or not. On the other hand, the number of particles they produce in a solution determines its osmolality, and therefore can be classified into iso-osmolar contrast media (IOCM),with similar osmolality than that of plasma, low-osmolar contrast media (LOCM), with higher osmolality than that of plasma but still lower than 900-1000 mOsm/kg, and high-osmolar contrast media (HOCM), with higher osmolality than that of plasma.
Adverse reactions of contrast media are multiple (nephrotoxicity, hypotension, hipervolemia, allergic reactions, etc).
The purpose of this document is to provide general guidelines to help avoid these adverse reactions.
Before specifying these recommendations, we believe appropriate to clarify the following points:

1)    These recommendations are made in view of the available evidence and experience, but with special regard to our Latin-American reality. We know there are products with less adverse reactions than others, but their cost makes it impossible for us to use them systematically. Given this reality, deciding to use these more expensive products requires for us to choose those patients at greater risk of adverse reactions.
2)    Adverse reactions are usually associated with the amount of administered contrast medium. Practitioners must bear in mind that one of the most efficient ways to prevent contrast media adverse reactions is to administer the least possible volume.
3)    Increase of temperature reduces contrast media viscosity, and therefore it is desirable to use heaters on a regular basis, to increase these agents’ temperature to 37° C.

These recommendations are not intended as inflexible procedures but as general action guidelines. Physicians must adapt the available evidence and experience to their actual reality.

Recommendations for the use of HOCM

Patients must fill in the following criteria:

1. Patients with no history of adverse reaction to contrast media (Ic recommendation).
2. Clinically stable patients with low risk of complications (IIb recommendation).
3. Patients with low risk of nephrotoxicity (IIc recommendation).

Recommendations for the use LOCM and IOCM

These agents are generally recommended for patients with high risk of developing complications during or after the procedure:

1) Patients with severe cardiac insufficiency (NYHA III-IV) (Ib recommendation) or with severe impaired ventricular function (IIb recommendation)
2) Patients in cardiogenic shock (Ib recommendation)
3) Patients with acute coronary syndrome: coronary myocardial infarction, acute coronary syndrome non ST elevation myocardial infarction (IIb recommendation)
4) Patients with high risk of severe allergic reaction to iodinated contrast agents. In this case, specific recommendation is to use nonionic contrast agents (IIb recommendation)
5) Chronic kidney disease in hemodialylsis (IIc recommendation)
6) Patients with severe aortic stenosis (IIb recommendation)
7) Patients with severe left main coronary artery lesion or single viable vessel (IIc recommendation)
8) Procedures on pediculated mammary artery bypass
9) (Ic recommendation)
    a. Patients with high risk of nephropathy induced by contrast media.
    b. Severe cardiac insufficiency (NYHA III-IV) (Ib recommendation)
    c. Prolonged hypotension requiring inotropic drugs and/or intra-aortic balloon pump
    support (Ib recommendation)
    d. Serum creatinine levels >1.5 mg/dl (IIa recommendation)
    e. Diabetes (IIb recommendation)
    f. Age > 75 (IIb recommendation)
    g. Dehydration not solved by the time of procedure (Ib recommendation)
    h. Severe comorbidity (Ic recommendation)
    i. Concurrent use of nephrotoxic drugs, e.g. non steroidal anti inflammatory drugs,
    loop diuretics, (IIb recommendation).
    j. Procedure requiring great volume of contrast [medium] (>5 ml/kg /serum creatinine
    level in mg/dl) (Ib recommendation).

Recommendations to prevent contrast [media] induced nephropathy

1) In patients at risk* of developing nephropathy induced by contrast media and with no contraindications, hydration with 0.9% saline solution (e.g.: 100ml/hr starting, if possible, 4 hours before the procedure and continued for 12 to 24 hours after the procedure) (Ia recommendation).
2) In patients at risk of developing nephropathy induced by contrast media and with no contraindications, hydration with sodium bicarbonate (e.g.: 154mEq/L solution infused at 3ml/kg 1 hour before the procedure, followed by 1 ml/kg/hr for 6 hours after the procedure) (IIb recommendation).
3) In patients with no risk of developing nephropathy induced by contrast media and with no contraindications, hydration with 0.9% saline solution (e.g.: 100ml/hr starting, if possible, 4 hours before the procedure and continued for 12 to 24 hours after the procedure) (IIb recommendation).
4) If possible, discontinue nephrotoxic drugs 48 hours before the procedure (Ib recommendation).
5) Limit contrast medium volume to the minimum necessary amount (5ml/kg/serum creatinine in mg/dl as maximum desirable level) (Ic recommendation)
6) Administer N-acetylcysteine in patients with a serum creatinine level >1.2mg/dl (e.g. 600 mg oral c/12 hours for 48hours starting the day before the study) (IIb recommendation).
7) Administer Mannitol and diuretics (especially loop diuretics) (IIa recommendation).
8) Avoid unjustified multiple procedures with contrast media in a short period of time (IIIc recommendation).

* Risk factors for contrast media induced nephropathy are:
1.    Serum creatinine level >1.5 mg/dl
2.    Diabetes
3.    Severe cardiac insufficiency
4.    Dehydration
5.    Prolonged hypotension requiring inotropic drugs and/or intra-aortic balloon pump support
6.    Age > 75
7.    Use of nephrotoxic drugs ( i.g. non steroidal anti inflammatory drugs, loop diuretics).
8.    Use of a great volume of contrast [medium] (>5 ml/kg /serum creatinine level in mg/dl)
 

Recommendations for early detection of contrast induced nephropathy

1. obtaining serum creatinine level previous to procedure (Ic recommendation)
2. obtaining serum creatinine levels 24 and 48 hrs after procedure, especially in patients at risk of contrast media induced nephropathy (IIc recommendation)
 

Recommendations for diabetic patients treated with biguanides

Discontinue biguanides, if possible, 48 hours before procedure and reestablish only when increase of serum creatinine has been ruled out (increased risk of lactic acidosis) (Ib recommendation).
 

Recommendations to prevent allergenic reactions

1.  Determine patient risk* before procedure. (Ic recommendation)
2.  With high risk patients undergoing coordination or emergency procedures:
     a. use non ionic contrast media (IIb recommendation)
     b. 30mg Prednisone orally 12 hours before procedure, repeating dose 2 hrs before procedure.
     (IIa recommendation if ionic contrast medium is used, IIb recommendation if non ionic contrast
     medium is used)
     c. H-1 antihistamines (e.g. Diphenhydramine 25-50mg intravenous monodosis) (IIb recommendation)
3.  With high risk patients undergoing emergency procedures:
     a. use non ionic contrast media (IIb recommendation)
     b. 200 mg intravenous Hydrocortisone immediately, followed by 200 mg intravenous every four
     hours for 24 hours or until stabilized (IIb recommendation).

*Risk factors for hypersensitivity to contrast media are:
1.  History of minor or severe adverse reactions to contrast media
2.  Asthma history
3.  History of allergic reactions that required treatment
 

Management of immediate hypersensitivity reactions to contrast media

General guidelines:
1.  Close watch of patients during first 20 minutes after procedure
2.  Crash cart within reach

Bronchospasm:
1.  4-6 L/min oxygen mask
2.  B2 Agonists, 2-3 shots or more, if necessary
3.  Adrenaline:
     a.  Normal blood pressure: i/m 1:1000, 0.1-0.3mL (0.1 – 0.3mg) (use the minimum dose,
     especially with elders or with patients with severe coronary disease)
     b.  Low blood pressure: i/m 1:1000, 0.5 ml (0.5 mg)

Anaphylaxis:
1.  4-6 L/min oxygen mask
2.  Adrenaline i/m 1:1000, 0.5 ml (0.5 mg), repeat if necessary

Isolated Hypotension:
1.  raise lower limbs
2.  4-6 L/min oxygen mask
3.  Saline 0.9% or lactated Ringer´s solution, repeat readjusting if necessary
4.  If no reaction: adrenaline i/m 1:1000, 0.5 ml (0.5 mg), repeat if necessary

Low blood pressure and bradycardia:
1.  Raise upper limbs
2.  4-6 L/Min oxygen mask
3.  Atropine 0.6-1.0 mg intravenous, repeat if necessary after 3-5 minutes (3 mg maximum dose)
4.  Saline 0.9% or lactated Ringer´s solution, repeat readjusting if necessary

Anaphylactic shock:
1.  Resuscitation maneuvers
2.  Aspiration of airway, if necessary
3.  Raise lower limbs if necessary
4.  4-6 L/Min oxygen mask or intubation if necessary
5.  Adrenaline i/m 1:1000, 0.5 ml (0.5 mg), repeat if necessary
6.  Saline 0.9% or lactated Ringer´s solution, repeat readjusting if necessary
7.  H-1 antihistamines (e.g. Diphenhydramine 25-50mg intravenous monodosis)
8.  B2 Agonists, 2-3 shots or more, if necessary