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Content Reviewed 09/30/2008



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Sonography


Example of proper room setup.
Figure 1. Example of proper room setup.

Using ultrasound equipment including the console, keyboard and transducer may present a significant risk of musculoskeletal disorders (MSDs) to the sonographer if not properly arranged. Due to the high cost of ultrasound equipment, older equipment may stay in use for some time. Older equipment often has the monitor, console and keyboard bundled into a single unit, allowing for few adjustments. In addition, the transducer is generally designed based on diagnostic performance and not necessarily for ease of use. Newer equipment is much more adjustable. When replacing this ultrasound equipment, models with maximum adjustability may help to prevent work-related MSDs.

Using the Transducer and Imaging Supplies

The transducer is the part of the ultrasound equipment that comes in contact with the patient's skin. It is almost always handheld and, depending on the application, it may be small or large. Generally, the transducer is made from a hard, smooth material to ensure that it can be adequately cleaned. Many procedures require the sonographer to exert force when pressing the head of the transducer toward the area of interest. To get the best picture of the affected area, the sound wave emitted from the transducer needs to be redirected during the process, often requiring the use of highly repetitive motions. In addition to the transducer, other items such as gloves and coupling agents may be necessary to improve the scans and provide sanitary conditions. Use and placement of these items may create additional hazards.


Potential Hazards

  • Use of highly repetitive motions and prolonged forceful hand exertions often in bent wrist postures when using the transducer. This increases the risk of injury to the hand, wrist and elbow.
     
  • Exerting force while the forearm is rotated, especially if the wrist is bent inward (flexed). This increases risk of injuries to the elbow.
     
  • Supporting or moving heavy cables repeatedly or for prolonged periods of time increases the risk of injury to the shoulder, arm and wrist.
     
  • This position in hyper-extension should be avoided. The forearm needs to be supported to reduce risk of injury to the shoulder. The weight of the cord causing torque needs to be removed from the operators wrist this can be accomplished by using a cable brace.
    Figure 2. The users wrist is bent and the arm is unsupported. The cord of the transducer creates drag on the transducer and increases the finger force which must be exerted.
  • Repeatedly dragging or pulling the transducer cable during scanning motions creates resistance to transducer movement causing torque. Torque increases the amount of force the muscles of the forearms must exert, increasing the risk of injury to the hand, wrist and elbow. (Figure 2)
     
  • Repeatedly using the thumb to push against the ledge of the transducer deQuervain's disease (tendonitis).
     
  • Resting the elbow or forearm on hard surfaces while scanning may compress nerves and blood vessels, increasing the risk of numbness and tingling in the fingers.
  • Using significant force to expel coupling agent gel, increasing the risk of injury to the hands, wrist and elbow.
     
  • Stretching and reaching beyond the control panel to access gel holders or boxes.
     
  • Using gloves that are too small, creating resistance when opening the hand, requiring additional force.
     
  • Using gloves that are too large, leaving excess material in the palm, increasing the force needed to close the hand around the tool.
     
  • Reduced tactile response of the fingers when using gloves, especially when combined with a lubricant. This also increases the hand force the sonographer must exert to gain adequate control of the transducer.

Possible Solutions

  • Provide transducers which minimize the risk to the sonographer.
    Operator holding transducer using a power grip.
    Figure 3. Operator holding transducer using a power grip.
    • The transducer should be lightweight and the contact point should be balanced to minimize the torque on the wrist.
    • A design that facilitates a power grip without a stretched and expanded hand posture.
    • A design that allows the wrist to stay in a neutral posture during many scans.
    • A design that minimizes the force which must be exerted. A flange on a long cylindrical handle or a change in orientation would provide a better power grip. (Figure 3)
    • Transducers should be of an appropriate size for the sonographers if at all possible.
    • The handles should have a slip-resistant surface.
  • Use arm rests or cushions to support the arm during scans. This reduces the muscle force needed to hold the arm and any devices held in the hand.
Operator has wrist and forearm supported, hand comfortably draped around the transducer, and cable brace in use reducing the torque on wrist.
Figure 4. Operator has wrist and forearm supported, hand comfortably draped around the transducer and cable brace in use, reducing the torque on wrist.
  • Transducer cables should be supported during the exam. A cable brace may be used to position cables overhead or along the arm. (Figure 4) Using a cable brace to manage transducer cable to minimize the amount of force exerted by muscles.
    • When using a cable brace, place it on the forearm of the scanning arm, just below the elbow.
      • Port connector permits ease of use, single-handed use, minimizing the  reach, force and necessity of a pinch grip. This does not interfere with access to equipment or system interaction.
    • Trap transducer cable underneath the strap on the cable brace. Lengthen the amount of cable between the transducer and the strap so that movement is not restricted.
    • Once the exam is completed, disconnect the cable brace, remove your glove and take a moment to stretch your hand, arm, shoulder and neck.
  • Ensure that the length of cables is appropriate for the procedures being performed. The cables should be long enough to provide unrestricted access to all other pieces of equipment after they are arranged, to minimize the sonographer's awkward posture. However, the cable should be short enough to minimize the weight, which must be supported during an exam.
     
  • Ensure transducer holder is easily accessible while keeping the elbow close to the torso. It should not require much force to remove the transducer from the holder.
     
  • Always scan while maintaining the arm in front of the body and abducted (spread) less than about 30 degrees.
     
  • Sonographers should not use the ledge of the transducer to push towards the patient's body. In addition, a standing position should be used, rather than sitting and pushing from the hips, when scanning bariatric patients.
     
  • Position yourself as close to the patient as possible to minimize reach distances.
    • Move around the table rather than reaching over the patient.
    • Keep the elbows close to the torso and the forearm approximately parallel with the floor. Reaching up to 20 inches can fatigue the arms in as little as 7 minutes. [Handbook of Human Factors and Ergonomics, 1997]
Wear gloves that fit and have textured fingers. Gloves that are to large can slip and reduce the force that can safely be exerted.
Figure 5. Wear gloves that fit and have textured fingers. Gloves that are too large can slip and reduce the force.
  • Store all imaging supplies within easy access in the examination area.

  • Use gel bottles with large openings to reduce the force needed to squeeze and extract gel.
     
  • Use gel bottles small enough in diameter to avoid excessive grip span.

  • Use gloves that are appropriately sized and as thin as possible, to minimize resistance. The gloves should be textured to improve tactile function and reduce force required to grip. "One size fits all" gloves are not suitable for ultrasound scanning as they do not always provide proper fit. (Figure 5)

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