deep vein thrombosis – All Sensors | Put the Pressure on Us

Welcome to All Sensors “Put the Pressure on Us” blog. This blog brings out pressure sensor aspects in a variety of applications inspired by headlines, consumer and industry requirements, market research, government activities, and you.

Pressure and Laparoscopic Surgery Part 2

The intravenous (IV) tube delivers saline and other chemicals to the patient before, during and after the laparoscopic surgery. Following the standard procedure, the IV bag is hung at least 3 feet above an adult patient’s heart to ensure there is sufficient pressure to keep the IV running at a constant rate. The height of three feet ensures a minimal pressure of 67.2 mmHg.

In addition to carbon dioxide (CO₂) pressure, blood pressure measurements and other pressures are involved in laparoscopic surgery. Three examples include an intravenous (IV) tube, spirometer, and an intermittent pneumatic compression (IPC) device.

A spirometer can be used to increase the patient’s post-surgery lung capacity. The process involves a graduated scale on a closed air cylinder, a movable piston, and a pointer. With an incentive spirometer, the patient inhales for as long as possible while holding the pointer within a specific range (constant negative pressure) to demonstrate lung capacity. Periodic usage helps patients to increase their post-surgery capability. Desired capacity can vary depending on age, height, and other factors but values around 2500 ml are not uncommon.

Image of an An intermittent pneumatic compression (IPC) device on the end of a hospital bed. The screen shows an illustration of three zones of the leg to which the device is applying a cycling pressure. — Intermittent Pneumatic Compression (IPC) device

An intermittent pneumatic compression (IPC) device cuff around a man's leg, with a blue hospital sock at the bottom. The leg is resting on a hospital bed. — A leg encased in an Intermittent Pneumatic Compression (IPC) cuff

An intermittent pneumatic compression (IPC) device applies a cycling pressure (figure shows three zones) to the leg after laparoscopic surgery to prevent a Venous Thromboembolism (VTE), including Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE). The device uses a cuff around each leg that are periodically and sequentially (from ankle towards the heart) filled with air and squeeze the patient’s legs. This process increases blood flow through the veins of the legs and helps prevent blood clots.

For other pressures involved in laparoscopic surgery see Pressure and Laparoscopic Surgery Part 1.

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Pressure and Compression Socks

Compression socks are often recommended to reduce swelling and prevent deep vein thrombosis (DVT) (blood clots) during travel and also to provide wound management. These type of socks or stockings put pressure on the legs to help blood vessels work better. Depending on the intent of their usage, compression socks have medical class ratings and pressure ranges specified in millimeters of mercury (mmHg).

Compression levels for over the counter socks are 15-20 mmHg, medical class 1 are 20-30 mmHg, medical class 2 are 30-40 mmHg and medical class 3 are 40-50 mmHg. In addition to these common ratings, there are other levels of compression as well. Socks with graduated compression have the strongest compression at the ankle and lighter compression as the sock goes up the leg.

Obviously, there are no sensors used in these socks but to have confidence in the pressure ratings, testing is performed when the socks are designed. Since medical issues are involved in their usage, testing should also be performed periodically during manufacturing for quality control purposes.

Compression socks are used for health care reasons, but that doesn’t mean they can’t be colorful.

Do you have a pressure sensing question? Let us know and we’ll address it in an upcoming blog.
Email us at [email protected]