header services logo masthead
The Exclusive Magazine for the Building Service Contracting Industry Since 1981

Ultrasonic Technology: The Next Service for Health Care Facilities

Written by  Michael A. Pinto


Many people do not realize just how serious the issue of secondary infections is in health care facilities. Variously known as nosocomial infections, health care acquired infections (HCAI), or hospital acquired infections, these mostly preventable health problems are the fourth leading cause of death in the United States. HCAI follows only heart disease, cancer, and stroke in the number of lives that they take every year. Unfortunately, nosocomial infections kill more people in our country each year than car accidents, fires, and drowning combined. According to the most current Centers for Disease Control statistics, on average in the United States, a patient dies of a hospital acquired infection nearly every five minutes.

One growing component of these HCAIs relates to a dramatic increase in problems associated with methicillin-resistant Staphylococcus aureus (MRSA). A Centers for Disease Control report stated that MRSA was responsible for an estimated 94,000 life-threatening infections and 18,650 deaths in 2005. (By comparison, 16,000 Americans died from AIDS that year.) And statistics show that MRSA infections are doubling in number every five years! HCAIs are expensive, too, with staph infections costing an estimated $14.5 billion in 2003.

Numerous studies show that hospital acquired infections can be reduced dramatically through an aggressive program of hand washing and surface cleaning. But the science also shows that MRSA is a pernicious foe, as it can survive on sterile packages for more than 38 weeks. One response to this deadly and expensive problem is to move toward stronger and stronger chemicals for cleaning purposes. Although this may provide some short-term relief, the side effects of harsh chemicals and the natural ability of bacteria and other infectious agents to develop a resistance to antimicrobials cries out for a new approach to cleaning in health care facilities.

Ultrasonic Cleaning Can Control Infections


Cleaning companies can step forward with a new option that has been proven to dramatically enhance normal cleaning procedures in health care facilities. Testing results show conclusively that ultrasonic cleaning equipment is capable of removing bacterial contamination from items typically used in both institutional and residen-tial settings. Three different studies support the contention that ultrasonic cleaning removes both gross contamination and microscopic bacterial pathogens. One of the studies showed that ultrasonic equipment can destroy the types of bacteria that pose the greatest concern to health professionals, with a strain of MRSA chosen to serve as a surrogate for such serious strains of microbial contamination. Equally important, field trials in two different hospitals demonstrated that supplementing normal cleaning procedures with ultrasonics improves infection control without being burdensome or overly expensive. (It should also be noted that the field testing in the hospitals was sponsored by the National Health Service in the United Kingdom as a demonstration project that was part of the Technology Innovation Program, which focuses specifically on reducing HCAIs.)

A History of Effective Cleaning

Ultrasonic2Ultrasonic cleaners use sound waves produced at frequencies higher than our ears can perceive. The process involves the use of a generator, called a transducer, in a water tank, which creates high-frequency sound waves. As the sound waves move through the liquid they create compression waves that “tear” the liquid apart, leaving behind many millions of microscopic voids or partial vacuum bubbles. (The technical name for this effect is cavitation.) These small bubbles expand and eventually implode when they strike an object, and this energy dislodges contaminants even from intricately shaped surfaces. The usefulness of ultrasonic cleaning with regard to biological pathogens such as bacteria and viruses has been known for some time. However, until recently, most of these efforts have been limited to small equipment like clamps and dental molds. The testing done on the Morantz units for efficacy on large items such as wheelchairs, commodes, and other common hospital items is truly groundbreaking in the ultrasonic industry.

Not All Ultrasonic Equipment Is the Same


While all ultrasonic cleaners work on the same principle of cavitation, there are critical differences in the design and function of the various machines. For example, manufacturers can generate sonic waves inside the tank of an ultrasonic cleaner in a variety of ways. Some attach the wave generator to the bottom of the tank, which dampens vibrations before they reach the cleaning solution. Other manufacturers extend vibrating rods from the generator into the solution. The testing showing the effectiveness of ultrasonic cleaning for controlling the spread of bacteria was done with units that use immersible transducer packs.

Impressive Test Results


The effectiveness of the tested equipment in dealing with contaminants typically found in health care facilities was proven by three different testing procedures. In all three tests, a common sense approach was followed. The ability of the ultrasonic equipment to kill microbial contaminants was measured by collecting samples from items prior to and after being cleaned. Immediate feedback was provided in all three studies by collecting samples on swabs that were analyzed by field equipment using adenosine triphosphate (ATP) technology. ATP instruments have a long history of use in food service and healthcare settings to determine the cleanliness of surfaces related to biological contaminants. Such instruments provide numerical results known as relative light units (RLU). In two of the studies, side-by-side surface samples were also analyzed by an independent laboratory to determine concentrations of specific types of bacteria.

The first independent test was conducted in order to determine if the cavitation process was as effective at removing bacteria as it was at dislodging dirt, grease, and other non-hazardous materials. A variety of residential and commercial items were tested, including toys, a wheelchair, and electronic components. The sampling data generated during the initial study revealed that the ultrasonic cleaning system was extremely effective in removing bacteria from items with heavy contamination. Bacterial reduction of nearly 100 percent was achieved for items that started with more than 1 million colonies of bacteria!

Work on the follow-up study had to be completed in a controlled environment, since representative items were intentionally contaminated with raw sewage and live MRSA. That study proved that organisms resistant to antibiotics can be effectively cleaned from surfaces using ultrasonic equipment, as MRSA bacteria were completely eliminated from contaminated surfaces by the ultrasonic cleaning.

The two earlier studies garnered interest from the National Health Service in England, as they aggressively attack the problem of HCAI. A three-month trial was extended to six months because of the impressive results. However, it is important to note that in the hospital study the “ultrasonics technology cleaning system was not intended to, and did not, replace standard cleaning. All equipment continued to be cleaned in the usual way.” In other words, the infection control experts understand that ultrasonic cleaning is a supplement to existing infection control efforts, not a process that supplants it.

The British study was prompted by their understanding of the ultrasonic cleaning process:

Ultrasonic technology is good at accessing inaccessible areas that normal cleaning cannot reach, for example screw threads and hinges. It is good at cleaning hard substrates. It has been found by researchers to be even more effective than thorough hand scrubbing, often observed in busy work areas. It involves less exposure to cleaning agents and, therefore, contributes to a reduction in skin damage.

More than 1,000 measurements were collected from items before and after cleaning during the course of the study at the two hospitals. A careful analysis of the data showed “an average of a 98 percent change in the RLU reading when the average Pre-Clean reading is compared with the average Post-Clean 2 reading.”

The results were so consistent and impressive that the researchers were able to draw a stronger correlation than expected. The stated goal was to measure the cleanliness of particular items with the expectation that better cleaning would, indeed, have a positive effect on the number of HCAIs. At the conclusion of the trial period the study authors noted, “The evaluation was not designed to assess the effectiveness of ultrasonics in reducing infection, but was it more effective than normal routine cleaning.”

At the conclusion of the study, hospital personnel had some specific recommendations and conclusions. They noted that the ultrasonic cleaning was especially useful for:

• WheelchairsUltrasonic1

• Commodes

• IV stands

• Cabinets 

• Tables 

• Chairs

• Trolleys

• Electrical fans

• Toys • Sac bins

Direct Implications for the Cleaning Industry

As health care organizations struggle with budgetary challenges, their attention is quickly turning toward minimizing HCAIs. Cleaning contractors are in a prime position to assist such organizations in a variety of ways. Ultrasonic cleaning of items that are known to spread infections can be offered in several fashions. Using a mobile unit mounted in a trailer or a van with contracts for specialized cleaning of large hospital items on a weekly or monthly basis using Morantz ultrasonic technology is one potential business approach. Another option would be to work with the facility to put a machine on site so that a larger number of items could be cleaned frequently. In this way, cleaning service providers can be key players in reducing health care acquired infections and limiting the personal suffering and financial loss that comes from these preventable diseases.

Michael A. Pinto, CSP, CMP, is chief executive officer of Wonder Makers Environmental, Inc. He focuses on common sense practices that work when health professionals are faced with threats from swine or avian flu, MRSA outbreaks, norovirus exposures, and nosocomial infection problems in healthcare facilities. Mr. Pinto is the author of more than 150 published articles and several books, including Fungal Contamination: A Comprehensive Guide for Remediation. He completed doctoral course work in environmental engineering and holds numerous certifications in the environmental and safety areas, including Certified Safety Professional and Certified Mold Professional. He conducted some of the testing described in this article but has no ownership connection to Morantz or other manufacturers of mentioned products. Michael can be reached at 269-382-4154 or This email address is being protected from spambots. You need JavaScript enabled to view it..

Leave a comment

Make sure you enter all the required information, indicated by an asterisk (*). HTML code is not allowed.