FAST, Echocardiography Principle | Medical Science Optional Notes for UPSC PDF Download

FAST 

FAST, which stands for Focused Assessment with Sonography for Trauma, is a swift diagnostic procedure designed to evaluate patients with potential thoracoabdominal injuries. The technique involves the following key aspects:

• Completion within 2-4 minutes.
• Positioning the patient in a supine posture.
• Utilizing a 3.5-5.0 MHz convex transducer.
• Scanning four distinct regions:
  • Subxiphoid transverse view: Examination for pericardial effusion and left lobe liver injuries.
  • Longitudinal view of the right upper quadrant: Evaluation for right liver injuries, right kidney injury, and Morison pouch.
  • Longitudinal view of the left upper quadrant: Assessment for splenic injury and left kidney injury.
  • Transverse and longitudinal views of the suprapubic region: Inspection of the bladder and pouch of Douglas.

The recommended sequence for assessment is as follows:

1. Pericardial
2. Right flank (hepatorenal view or "Morison's pouch")
3. Left flank (perisplenic view)
4. Pelvic (retrovesical views)

eFAST

A comprehensive Extended FAST (eFAST) scan can be conducted, involving left and right thoracic views to evaluate the presence of pneumothorax and hemothorax.

Echocardiography-Principle

Echocardiography employs high-frequency sound waves (ultrasound) to permeate the body, bounce off relevant structures, and produce an image. The fundamental physical principles of echocardiography mirror those of other ultrasound imaging methods, although the hardware and software are specifically optimized for assessing cardiac structure and function. Beyond generating 2D images that offer insights into cardiac anatomy and performance, echocardiography can investigate blood flow within the heart and blood vessels using the Doppler principle to determine blood flow velocity. In the early days, echocardiography machines presented "M-mode" echocardiograms, where a single ultrasound beam was depicted over time on a moving sheet of paper.

Contemporary echocardiography equipment employs phased array transducers equipped with up to 512 elements, emitting ultrasound sequentially. The receiving elements capture the reflected ultrasound, and an apparatus called a "scan converter" utilizes details regarding the timing and intensity of the reflected ultrasound to produce an image.

Echocardiography-Variants

• Transesophageal echocardiography
  • Enhancing ultrasound frequency improves resolution but comes at the cost of reduced penetration. Higher frequencies find utility in pediatric imaging or transesophageal echocardiography, where the transducer can be in close proximity to the structures under examination. This serves as a rationale for employing transesophageal echocardiography to capture higher-quality images. This procedure offers unobstructed views of cardiac structures without the need to penetrate through the chest wall, muscles, and ribs.
  • Transesophageal echocardiography has emerged as the preferred diagnostic method for evaluating small lesions in the heart, such as valvular vegetations, especially in cases of prosthetic valve disease, and intracardiac thrombi. It is particularly valuable for assessing the left atrial appendage, which is challenging to visualize with standard transthoracic imaging, as well as for evaluating congenital abnormalities.
• 3D ECHO
  • The utilization of three-dimensional echocardiography is on the rise for assessing congenital heart disease and valves, even though the current image quality lags behind 2D ultrasound.

Stress echocardiograph

Routine application of stress echocardiography involves evaluating cardiac function during physical exercise. It proves valuable for identifying myocardial ischemia and assessing valvular function under conditions of exertion.

Echocardiography Applications

The major ions for the technique are

• Function of the ventricles
• Congenital heart anomalies
• Diseases affecting heart valves
• Cardiomyopathies
• Accumulation of fluid around the heart (Pericardial effusion)
• Cases where cardiac masses are suspected
• Aortic conditions (Proximal region)