Patient Care, Safety, and Professional Standards
Bioeffects and the output display
The two mechanisms of ultrasound bioeffect are thermal (measured by thermal index) and mechanical (measured by mechanical index, reflecting cavitation risk). The output display standard shows MI and TI on screen; keep the mechanical index at or below 1.9 and follow ALARA - as low as reasonably achievable - by minimizing output and dwell time, especially with contrast agents and in the first trimester. Higher MI is used deliberately with agitated saline and contrast to induce microbubble destruction.
Infection control and equipment
Surface probes are low-level disinfected between patients. Transesophageal and endocavitary probes are semi-critical devices and require high-level disinfection after each use, with documented cycles. Use sterile gel and probe covers for invasive or intraoperative studies. Transducer damage comes from heat, dropping, and improper chemical exposure, not from routine scanning.
Patient care
Position the patient in the left lateral decubitus position for apical windows; use breath-hold in expiration to reduce lung interference. Continuous ECG monitoring, blood pressure, and symptom assessment are the sonographer's responsibility during stress and transesophageal studies. Obtain informed consent for transesophageal and stress echocardiography. Recognize critical findings - tamponade, dissection flap, right heart strain from pulmonary embolism, ruptured chordae - and escalate immediately rather than finishing the protocol.
Professional standards
Maintain confidentiality under HIPAA, document measurements and limitations honestly, use accepted nomenclature and reporting guidelines, and practice good ergonomics to prevent musculoskeletal injury.
Traps and rule of thumb
Routine echocardiography does not require endocarditis prophylaxis, and ultrasound contrast is contraindicated with known hypersensitivity or intra-arterial administration. Rule of thumb: if you cannot justify the exposure, the output or the dwell time is too high.