US-Guided Procedures

last updated: October 30, 2016

Orlando Debesa

Advantages

  • no ionizing radiation risks (unlike CT or fluoroscopy)

Literature Review

  • increased success rate

  • decreased complications

Psychomotor skills

  • visualize the target of interest and guide and instrument towards the target

  • being able to view 3D anatomy on a 2D screen

  • manupilating the transducer in multiple planes

  • scanning a structure of interest in at least two orthogonal planes

  • acquiring the given image for a given clinical indication

Procedural Skill Decay

  • novice learners decay - practice prevents this

Pre-Procedure Planning

  • ergonomic planning

    • position the machine so the practioners head remains fixed minimizing head movement and body rotation

    • screen and procedure site should be in the same line of site

  • infection prevention

    • maximal sterile barrier precautions​

    • transparent adherent sterile dressing (eg. Tegaderm) can be placed on the transducer as an additional sterile barrier

    • sterile acoustic coupling gel

  • optimal machine and transducer type

  • patient positioning

  • provisions of local and systemic analgesia

  • patient consent when relevant

  • review of relevant medical data

Femoral Anatomy

Thyroid

  • 10-20 grams

  • located anterior to 2-3rd tracheal ring

  • 2 lobes

  • isthmus (bridge connector)

  • pyramidal lobe (10-40%)

  • 40-60 mm length

  • Anteroposterior 13-18 mm (if >2cm = maybe considered enlarged)

  • size and shape of the thyroid lobes vary widely in normal patients

  • parenchyma is normally homogeneous

  • hyperechoic capsule surrounds the thyroid

  • thyroid has rich vascularity on Doppler

  • esophagus - usually on the left side

... but I would more especially commend the clinician who, in acute diseases, by which the bulk of mankind are cutoff, conducts the treatment better than others.
 
Hippocrates, 400 BC