Ultrasound

The ultrasound machine is part of every anesthesiologist's armamentarium. We most commonly use it for putting in central venous access, scanning the internal jugular or femoral veins. But ultrasound can also be a tool for placing difficult IVs or arterial lines, evaluating the heart (both transthoracic and transesophageal), and placing nerve blocks. Thus, my month on regional anesthesia taught me a lot about ultrasound.

Most physicians can get away with a rudimentary understanding of the physics, machine, and computing algorithms. However, to successfully do nerve blocks, anesthesiologists need more than a superficial understanding of ultrasound. Our targets are millimeters wide but can be several centimeters deep. They are surrounded by critical structures and can be tricky to visualize. The goal is to see the needle tip at every moment as it reaches the target. This seems easy, but getting the needle, ultrasound beam, and target aligned in one view is an incredibly challenging technical skill to learn.

Ultrasound taught my hand fine, miniscule movements. When I first started, I thought I made small adjustments, but I was moving the probe millimeters at a time - a reasonable action if I were placing a central line into a jugular vein, but ineffective in locating a bundle of peripheral nerves. But over the four weeks, I developed better judgment in directing my needle at the right angle and trajectory and better muscle memory in adjusting the ultrasound beam to catch the needle and target at once.

Furthermore, I gained a deeper understanding of ultrasound physics and mechanics. Though it sounds dry, it helped me understand how to select the correct probe and orientation for each block. The more challenging aspect was learning how to adjust the machine's algorithms in displaying the data. Sometimes when visualization is poor, changing how the ultrasound waves are interpreted can make a needle or target more apparent. As a medical student, I was intimidated by how many knobs and dials the ultrasound machine had; now I have a reasonable understanding of what they do and how to use them.