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The Pressure in Hospital Isolation Rooms

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. In this blog we’ll be discussing pressure in hospitals.

The Pressure in Hospital Isolation Rooms

Infectious diseases and chronically ill patients require special air handling equipment in hospital isolation rooms. The isolation could dictate either positive or negative pressure in the room.

An isolation room at negative pressure has a lower pressure than that of adjacent areas. This keeps air from flowing out of the isolation room and into adjacent rooms or areas. In contrast, higher (positive) air pressure in the isolation room than in the adjacent corridor or anteroom prevents transmission from the outside environment to severely immunosuppressed patients.

Historically, the transmission of tuberculosis has been a concern for many years. The Centers for Disease Control and Prevention (CDC) published and updated “Guidelines for Preventing the Transmission of Mycobacterium tuberculosis in Health-Care Settings, 2005” a little over a decade ago and identified the need for a negative pressure of at least 0 .001 inch of water to prevent spreading the disease. More recently, Avian Bird Flu H5N1, another highly contagious disease, has raised the need for isolation and negative pressure control. A pandemic disaster or chemical warfare could further increase the number of negative pressure isolation rooms/wards required in a community.

Monitoring the room to outside differential pressure can be performed with manual techniques such as visually observing the direction of airflow using smoke tubes or with a pressure gauge. Both of these approaches require the person monitoring the room pressure to be at the room. With today’s lower pressure and cost-effective MEMS sensors, remote monitoring can easily be implemented so an expert (or experts) responsible for ensuring the positive pressure does not have to physically close to the patient’s room – and receives the warning of a problem in real-time.

A pressure monitoring gauge is part of the isolation room equipment to monitor airflow. Source: http://biologicalcontrols.com/excbb.shtml

What do you think/Comments?
Do you have a pressure sensing question? Let me know and I’ll address it in an upcoming blog.
-Han Mai, Senior Marketing Specialist, All Sensors Corporation ([email protected])

Positive Pressure Personnel Suit

Reports of Centers for Disease Control and Prevention (CDC) biolab failures often provide a dramatic picture of a person in a HAZMAT (positive pressure) suit to demonstrate the hazardous environment. In fact, ventilated and reusable pressurized protective suits are available for use in Bio Safety Level 4 (BSL-4, deathly viruses) laboratories worldwide.

Source: https://en.wikipedia.org/wiki/Positive_pressure_personnel_suit

According to the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID), there are four levels of biological containment, with BSL-4 being the highest level. In this environment, personnel must wear positive-pressure suits commonly called “space suits” and breathe filtered air. The air-tight suits are designed for positive pressure to prevent contamination to the wearer even if the suit becomes damaged.

One company offers a ventilated protective suit for BSL4-1 environments that can withstand a 5.4 bar (78.3 psi) pressure and has a valve for continuous adjustment.

Typical use for a BSL 4-1 biohazard suit could occur in industries such as:

Chemical
Oil and Gas
Pharmaceutical

To detect leaks, especially when the suit is used infrequently, periodic pressurized testing must be performed to maintain the integrity if the suit.

Source: https://en.wikipedia.org/wiki/Positive_pressure_personnel_suit

May: National High Blood Pressure Education Month

Do not over inflate! For tires this means air pressure but for humans it means blood pressure. With high blood pressure, a person’s artery walls can fail and ultimately be the cause of death. With this in mind, the US Centers for Disease Control and Prevention (CDC) has designated May as National High Blood Pressure Education Month. The facts are:

Data from 2010 indicates that 1,000 deaths occurred each day in America due at least in part to high blood pressure.
In the US, about 1 of 3 adults or 67 million people has high blood pressure.

Target desirable readings are 120 over 80: a systolic (top) number of 120 millimeters of mercury (mmHg) and a diastolic (bottom) number of 80 mmHg. The top number is the pressure caused by the heart pumping blood and the bottom number is the value between beats. Higher values of 139 systolic and 80–89 diastolic indicate prehypertension. A person with a systolic reading of 140 or greater or diastolic value of 90 or greater has hypertension.

The mechanical sphygmomanometer remains one of the tools to measure blood pressure. However, MEMS pressure sensors provide accurate and easily automated measurements for digital pressure measurements and monitoring, especially in post-surgery and other critical situations. The American Heart Association has stated, “Accurate measurement of blood pressure is essential to classify individuals, to ascertain blood pressure–related risk, and to guide management.” While technique, cuff size, position, time of day and other factors are important for accurate measurements, accuracy starts at the level of the basic sensing element.

What do you think/Comments?
Do you have a pressure sensing question? Let me know and I’ll address it in an upcoming blog.
-Dan DeFalco, Marketing Manager, All Sensors Corporation ([email protected])