The Laboratory

4 The Laboratory


Equipment


images Design of the Facilities and Equipment


Standards for cardiac catheterization laboratories have been published. The catheterization laboratory must be in close proximity to a cardiac care unit or an intensive medical unit and have sufficient space (≥ 30 m2). The following equipment should be present in the catheterization laboratory:


images Defibrillator with battery operation


images Temporary pacemaker


images Emergency medications in sufficient amounts


images Capabilities for artificial ventilation as well as oxygen and compressed air supply


images Blood gas analyzer


images Pulse oximetry


images Suction


images Operating lights


images Emergency power generator for the cardiac catheterization room, control room, and recovery room


For some specific techniques such as high-frequency rotablation, sufficient access to pressurized air (140 L/min, at least 650 kPa [6.5 bar]) is required. For complex interventions, in cooperation with anesthesia and cardiac surgery, wall connectors for oxygen and pressurized air to run the anesthesia apparatus should be available.


images Angiography System


Although the basic layout of a catheterization system has changed little over time (layout of a modern biplane catheterization laboratory; Fig. 4.1), there have been substantial technical improvements in recent years, especially with regard to the following:


images Significantly improved X-ray utilization through improvements in tube technology


images More efficient use of photons by the image intensifier, with improved contrast resolution


images Transition to digital technology in both imaging and recording of hemodynamic data


images A comfortable, easily movable patient table, which has to be accessible from all sides (especially in the case of resuscitation)


images Stand with image intensifier/flat panel detector and Xray tube


images X-ray generator with tube


images Image intensifier for image recording (if possible three input formats; zoom) or alternatively a flat panel detector for image recording


To be able to evaluate the heart from different projections, the X-ray tube and image intensifier have to be movable (rotation range ± 90°; angulation range ± 40°). Particularly for interventions, a biplane system has the advantage that it allows simultaneously different projections for fluoroscopy and image documentation and thus saves both contrast media and time. Alternatively, modern single-plane systems with the possibility for rotational angiography can be used.


Image transmission occurs via an image intensifier–television combination or flat panel technology. At least one monitor per plane is required in the catheterization room and the control room (diagonal diameter of the monitors in the catheterization room should be at least 44 cm). In the catheterization laboratory there is an additional monitor per plane to save and display a reference image. Additional monitors are required to show the hemodynamic data. Ideally, another monitor should be available for imaging external data (echocardiography or three-dimensional mapping system for electrophysiological interventions).


For interventional cardiology additional specific requirements were made for the catheterization system (Table 4.1).



Table 4.1 Specific requirements for the catheterization system for interventional applications








– Extended protection against radiation at the patient table


– Automatic angle adjustment or automatic angle display


– Generator power ≥ 100 kW, continuous power > 2 kW


– Source image distance (SID) tracking (automatic dose regulation with subsequent reduction of the tube current with reduction of the focal spot–image intensifier distance)


– Last image hold (“freeze frame”) or last image run (storage image), two monitors per plane


– Roadmapping: device-based orientation aid for catheter direction during interventions


– Pulsed fluoroscopy, pulse width (1–10 ms, selectable), frame rates (3–25/s, selectable)


– Additional filters for fluoroscopy of at least 0.1 to 0.5 mm Cu equivalent, special grid (mm ≤ 1.8)


– Aperture system (iris diaphragm, for overframing rectangular and semitransparent diaphragm)


– Image intensifier with at least three input formats (e.g., 13, 17, and 23 cm)



Image Recording


Digitized recording of coronary angiography and hemodynamic data is now standard. Digital image quality is determined by matrix size and depth. For example, a 512 × 512 matrix consists of 512 rows and 512 columns and thus 262,144 pixels (minimum requirement for coronary angiography.) The image depth is expressed in bits. Eight bits allow visualization of 28 = 256 gray scale divisions, whereas 10 bits allow 1,024 gray scale divisions.
Hence, for a 512 × 512 matrix with an image depth of 8 bits (where 8 bits = 1 byte) the data amount per image is 512 × 512 × 1 byte = 262,144 bytes, which is 256 kilobytes (where 1 kilobyte = 1,024 bytes). The major advantages of digital imaging and digital storage are as follows:


images Immediate availability of images


images Higher image quality, e.g., significantly increased image contrast


images The possibility of image processing (automatic/manual) → higher image quality, diagnostically more conclusive


images Image recording in real-time, no data loss


images The availability of digital analysis possible (electronic measurements, automatic contour recognition of the ventricles, etc.)


images Cost-saving and space-saving digital storage of the images (1 CD/patient → an unlimited number of patients depending on the server configuration when using a picture archiving and communication system)


images The ability to transit images via digital data networks

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Jun 4, 2016 | Posted by in CARDIAC SURGERY | Comments Off on The Laboratory

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