The Mobile Isolation Chamber: A Cleanroom Alternative

Henry Rahe
Technology Advisor
Containment Technologies Group, Inc.

Hospital Pharmacy and Home Health Care providers are currently facing change at a rapid rate in all facets of their business. Delivery of products and services has changed from the longer term in hospital treatment basis, to one in which many procedures are being performed outpatient, with recovery in an intermediate or home environment. This change, in combination with the ever increasing spread of more resistant, infectious diseases and the increased risk of exposure, due in part to the increase in travel by the population and poorer preventive health measures, has created a situation demanding a change in the level of protection provided by equipment used in the pharmacy.

The impact of the increasing burden placed upon the traditional preparation environment for parenteral products, that is open laminar flow hoods, can have implications that go undetected for years in the new health care delivery format. An infected individual preparing IV piggybacks in the pharmacy has the potential of exposing numerous patients, who are already in a compromised condition, to the disease(s) which they are carrying before they become aware of their illness. Connecting the patients, contracting an unrelated infectious disease and no longer under direct hospital supervision, to the source of infection would be difficult at best.

According to a recent article published by Knight-Ridder newspapers (January 17, 1996 Indianapolis, IN Star), the increase in infectious blood diseases resulting in death is over 350% between 1980 and 1992.

Cleanroom technology has been suggested as a means of improving the current environment in the pharmacy. This technology, when it was adopted for manufacturing of parenteral products over thirty years ago, greatly improved the sterility assurance level of parenteral products. Though cleanroom technology does reduce the potential for exposure, by controlling air flow direction, it does not remove personnel, the primary source of contamination, from the critical zone of product exposure. Procedural dependence plays a significant role with this technology, in terms of the positioning of both personnel and materials within the laminar flow environment. Personnel entering such an environment require training and certification in the proper gowning techniques. This technology will always have application, however, in today's pharmacy a better alternative exists in barrier/isolation technology.

Following the experience base of pharmaceutical manufacturers, who have turned to the use of barrier/isolation technology as a means of improving sterility assurance and reducing both capital and operating costs, European hospital pharmacies started using barrier/isolation technology over five years ago.

The development of barrier/isolation technology for pharmacy applications in Great Britain began with mixed results. Initially units were manufactured without consideration of the application, resulting in misuse and improper maintenance of the equipment. To correct these errors the British established a group, drawing from the users, manufacturers and regulatory people, to develop a guide for the manufacture and use of isolators in hospital pharmacy applications. This work was completed in 1994.

In the United States, barrier/isolation technology is following the same evolution with a greater time lapse. This lag can be contributed to the difference in the source of regulatory control. In the US, regulatory control of hospitals is a state agency responsibility, resulting in differences on a state by state basis. Requirements in the form of guidelines published by ASHP (American Society of Health-System Pharmacist) and the US Pharmacopoeia give the industry a platform without enforcement. The only compliance body reaching across state lines is the Joint Commission on Accreditation of Healthcare Organizations (JCAHO). However, even JCAHO does not define practice or procedure, but uses the manufacturer's guidelines or procedures for determination of what is proper.

Herein lies a significant problem for the pharmacy. The lack of knowledge and understanding of the equipment, by the Pharmacist and a major knowledge gap of the functions being performed in the pharmacy, by the equipment manufacturer. Due to this lack of understanding, the technical innovations are limited in the areas of non disciplined activity.

Gaining the attention of the 'maker of the rules' by outside experts is a difficult and challenging task. People within the Pharmacy profession are focused on their area of expertise and interested in providing quality service to their customers.

The approach and results to date, of Containment Technologies Group, Inc. in developing barrier/isolation technology for the Pharmacy will be explored in this paper.

The beginning elements for development of the mobile isolation chamber (MIC) started with a hospital Pharmacist's dissatisfaction with the limitations of her laminar flow hoods. This need, combined with an engineer's awareness of and respect for the capabilities of barrier/isolation technology, helped initiate the plan for the development of the mobile isolation chamber (MIC).

DEVELOPING THE MOBILE ISOLATION CHAMBER

When introducing any new technology, the major issue to be dealt with is 'change'. People do not like change. The majority of people develop a routine to their working and any disruption to that pattern is perceived as a negative, which must be overcome. Having introduced barrier/isolation technology into pharmaceutical manufacturing helped in the development of an approach to introducing it to pharmacy personnel. The approach was to gain an understanding of the function, or what the people were doing in the pharmacy and how they were doing it. A key to this approach was not only understanding the physical activity, but also the negatives in the existing system. These negatives for laminar flow hoods turned out to be a surprise. The expectation was, the increased safety of barrier/isolation would be the major positive factor, based on previous experience. However, the major positives of the mobile isolation chamber was less noise, less heat and the mobility of the unit. Each of these items were negatives for the laminar flow hoods.

The administration expectations were much more straight forward and can be summed up in two elements; meet regulatory requirements and be cost effective.

UNDERSTANDING CUSTOMER REQUIREMENTS

Understanding the routine operations in a pharmacy was accomplished by interviews with several experienced pharmacists and pharmacy technicians. The reality check of the operations was accomplished in conjunction with the University of Cincinnati Hospitals working with Paul Mosko, Assistant Director. A number of time studies were conducted to establish a database for comparison to the MIC system. This not only provided a measurement tool for the management objective of cost effectiveness, but also helped gain an understanding of the actual method and practice used by personnel in performing their tasks.

THE BASICS OF GOOD BARRIER/ISOLATION DESIGN

The prototype MIC unit was developed, combining the knowledge of function with good design for a barrier/isolator system. Good design of such a system includes making choices, that match functional requirements with system capability, in each of the four key components of the system. The four basic components of such a system are; the physical structure or shell of the unit, the air quality or filter and air handling system, the transfer technologies both for product and personnel interactions, and the monitoring systems.

The criteria for selection of materials of construction for the shell should include a cost value analysis of the alternative materials. Typical materials for consideration are plastic soft shell (material 9 to 30 mil in thickness), hard plastic and stainless steel. Viewing areas were engineered plastic for safety and durability.

The analysis chose stainless steel because of its durability, in an environment containing needles and other sharp objects. Experience, in the sterility testing units in the pharmaceutical industry, has shown testing and replacement of (soft shell) "bubble" units not to be cost effective. Another factor, contributing to this decision, was the flexibility stainless steel allows in the selection of cleaning and sanitizing agents. The integrity of the shell is the core of this technology and must be designed, constructed and validated to a standard which will assure containment of the internal environment.

Selection of the quality of the internal environment was defined by the need to establish and maintain Class 100 conditions. Traditionally, this level of air quality was obtained by using laminar flow, which moves large volumes of air through a high efficient filter, removing particles from the air stream. Rating of these filters, called HEPA, are in terms of the percentages of particles removed, above a given particle size. Typical efficiency ratings are 99.97% or greater at a particle size of 0.5 micron.

A 0.5 micron filter will generally remove most bacteria from the air stream. This is based upon the fact that many bacteria attach themselves to larger particles which are captured in the filter media.

For the MIC system, it was decided to use non laminar flow air and instead, use HEPA filtration for both the entrance and discharge filters. Utilizing this approach with recirculation of more than 90% of the air. Air quality of less than Class 10 was observed during validation of the unit.

Other decisions, regarding air pressurization, were to develop both a positive and negative pressure systems for the MIC. The negative pressure system is primarily for cancer center applications.

Transfer technologies for interaction of the Pharmacist and the product, involved a review of proven technologies, including half suits and two types of glove and sleeve arrangements. The half suit alternative offers advantage in lifting of materials inside the isolator and allows increased mobility when reaching inside a large isolator. Neither of these factors were critical in the review of typical pharmacy operations. Disadvantages of the half suit are the space it would require and it does not offer the ease of entrance and exit found in the glove sleeve alternative.

Selection of the two piece glove sleeve arrangement was based upon the customer profile. Typically, several different people would be using the system during a work shift. The range of hand sizes were significant and the requirement for manipulation important, which pointed to the use of individual sized gloves, that could be changed quickly. The separate glove sleeve type arrangement had both functional and economic advantage for this application.

The three alternatives for movement of materials into and out of the MIC was a difficult decision. The best technology, the double door posting port approach, was the most expensive and not as user friendly as the air lock alternative. Testing showed that Class 100 conditions could be maintained within the air lock system. Because of the advantages in movement of a variety of material sizes and shapes the air lock alternative was chosen. As a result, the Pharmacist has maximum flexibility in the preparation of a number of products.

Monitoring is a complex and costly activity and it is important to achieve a proper balance between need and want. Important parameters for monitoring a barrier/isolator system are the indication that the air handling system is operating properly and the shell has integrity. Both of these functions can be monitored with a pressure differential gauge. This has proven to be the most cost effective solution.

DEVELOPING A PROTOTYPE FOR EVALUATION

With the MIC system defined, the next step was construction of a prototype for evaluation at the University of Cincinnati Hospitals. Testing was designed to gather both ergonomic feedback and an indication of performance, compared to the standard laminar flow hood arrangements.

The ergonomic feedback was collected during interviews before and after the time study. Using this technique, information was gathered about expectations and concerns of using the MIC approach. Consistently, the initial expectations were less productivity. This expectation was attributed to the perceived lack of freedom of movement that the hood allowed. Results proved this untrue.

The key to success of the performance of the MIC was an organized method and consistent approach to the task. The method adopted for inputting materials into the MIC was a tray or basket, in which materials were organized for use inside the unit. The time for this activity was included in the time study as prep time. The MIC approach proved to be slightly more productive in all cases, with a significant advantage where gowning was required (cleanroom).

The major lessons learned from the initial prototype were a need for height adjustment and interior hanger bar adjustment. These changes were implemented in the second prototype and additional testing conducted.

Additional test sites included Johns Hopkins Hospital in Baltimore, MD, and Saint Vincent Hospital in Indianapolis, IN. Each site involved multiple testing personnel with a focus on the fine tuning of the ergonomics. The additional suggestions have been incorporated into production models.

SUMMARY

Customer input through evaluation of the prototype created positive changes which would not have been included in the production models.

Customer ideas of features that were important were consistent across all test sites, but different than the initial expectations.

Customer acceptance of change is difficult and must include involvement with the new technology.