Pneumatic tube system: optimum approach to Stat specimen transport.
The author s manager of laboratory services at Thomas Jefferson University Hospital in Philadephia.
Even though we liked to consider ourselves a full-service laboratory, one area needed improvement. The medical staff at our 707-bed hospital kept complaining about slow turnaround times for Stat specimens.
This, despite repeated laboratory demonstrations over the years that tests took an average of 30 minutes to complete. We also offered many of the specimen collection and reporting services that could be expected of a modern clinical laboratory in a tertiary care center: There was hourly phlebotomy service from 7 a.m. to 11 p.m., along with messenger pickups for the critical areas on night shift; the laboratory computer, used for result processing, interfaced with the hospital mainframe; we charted cumulative reports at the nursing units; and we printed complete reports for medical records upon patient discharge.
Nevertheless, complaints (usually nonspecific) held that Stats took hours to run. Investigation by the lab invariably found delays in transporting specimens to the laboratory, not within the laboratory itself.
One proposed solution was hospitalwide Stat messenger service, not only for delivery of specimens but also for such items as medications and radiology films. This was deemed too expensive, however. Other drawbacks: messengers spend much time in a waiting state, unexpected absences cause breaks in service, and critical items may be lost or delayed in transit because of a human lapse.
Then several years ago, we became familiar with the new generation of pneumatic tube systems in use at hospitals. Unlike the older versions that gave a small payload a bumpy ride, the newer models employed pressure and vacuum to gently propel spec'lmens. These specimens were cushioned by foam rubber pads inside containers called carriers. A buildup of air pressure softened the landing and prevented any sharp deceleration that might damage the specimen containers.
We took a much closer look at this option three years ago when the hospital received state approval to perform liver transplants. Because the condition of patients after a transplant can be precarious, the surgeons told the laboratory in no uncertain terms that Stat services had to improve.
The laboratory promptly initiated Stat messenger service from the surgical intensive care unit during the first 36 hours following a liver transplant. This was not an efficient solution, however. Most of the messengers were laboratory personnel on overtime, and the cost for specimen transport averaged $620 per liver patient. With two transplants a month, the annual messenger cost would amount to $15,000.
In addition, scheduling confusion arose. It was hard to predict exactly when a patient would arrive at the SICU after the operation.
Now the laboratory had a specific, compelling reason to improve Stat turnaround time and the means to do it. All we had to do was convince hospital administration that a pneumatic tube system would be worth the large capital expenditure.
The first step was to meet with the clinical laboratory services committee, a hospital-based group composed of physicians plus ex-officio staff members from nursing, quality assurance, pharmacy, and care program management. This committee functions as a review board to insure that the laboratory meets the primary needs of the medical staff. It considered a pneumatic tube system at .its meetings in March and April 1986.
At that time, the laboratory received about 140 Stat specimens per day from medical staff messengers-typically nurses, residents, medical students, and clerks. An average of 67 more daily Stats came in from the emergency room via laboratory messengers.
We described the following pneumatic tube advantages to the laboratory services committee:
The system would directly benefit patient care by speeding up results that are needed Stat.
A pneumatic tube is a simple straightforward device. It is easy to use and requires very little training. It is also normally highly re)lable and, with a small amount of care, not very susceptible to errors.
The tube would handle transport of Stat specimens 24 hours a day, seven days a week, with no breaks, vacations, or sick leave.
Nurses and others delivering Stat specimens would be freed to devote more time to their direct patient care duties.
The tube system would replace the laboratory's liver transplant messengers for an immediate annual saving of about $15 ,000. It would also replace lab messengers on the third shift for an annual saving of $23,000.
Once the initial installation is paid for, there are very few recurring costs. In-house personnel can handle most maintenance.
The emergency room could discharge patients or admit them to the hospital more rapidly. The laboratory's half-hour specimen delivery schedule sometimes delayed result reporting.
The laboratory could communicate outpatient Stat results more promptly, reducing delays for patients whose medical treatment awaits test data.
Limiting usage of the tube system to Stats would reduce carrier traffic and improve the transport time. Specimen processing in the Stat area would also go much faster if the incoming Stat work did not have to be separated from routine work.
The committee agreed that the pneumatic tube was needed. It approved the laboratory proposal for tube stations in the lab and at critical care units, the intensive care nursery, the delivery room, operating rooms, the emergency room, and two outpatient collection areas.
In fact, the committee added several more stations: nursing units in the central area of each floor as collection points for Stats from routine care units, a decentralized pharmacy station for delivery of Stat medications during off-hours and weekends, and the radiology reading room to obtain films rapidly from the emergency room. This plan was endorsed by hospital administration.
One major question was which of the two available system types would best meet our needs. Pointto-point systems are usually employed for a small number of stations. They connect two points and offer simplicity, reliability, and ease of use-a carrier cannot be sent to the wrong location. The other type, multistation computercontrolled systems, is intended for larger installations.
We in the laboratory were initially attracted to the point-topoint model. It was a simple, direct approach with little downtime, no difficulty with system overloading (slow transit time caused when several carriers are sent simultaneously), and no possibility of misdirecting a specimen. We learned of cost and space drawbacks, however, when a number of locations are served on a point-to-point basis.
Each point-to-point installation is a complete system with its own tubing, stations, and blower (for propulsion), making it very expensive to provide a network of connections. Each such installation also requires a station at either end. If specimens are to be sent from 10 hospital areas, the laboratory will need 10 stations along a significant amount of wall space. In addition, the tubing could present difficulties as it rapidly fills the interstitial or mechanical spaces approaching the laboratory.
The vendors actually made the decision for us by recommending a computerized system if we intended to install more than five or six stations. They cited these reasons: It is less costly than separate point-to-point systems; new stations can be added more economically simply by connecting to the nearest tube; the computer can shut down particular stations when they are not needed (such as the outpatient areas on weekends); the computer provides various alarm functions; and less hardware, space, and power are required.
Another choice involved the carriers. These torpedo-shaped holders come in four- and six-inch diameters. The latter can hold more specimens and larger individual items; their payload is 7 lbs. of material versus 2.75 lbs. for the smaller carriers. On the other hand, their wider tubing costs more to install and takes up more space inside the walls, especially to allow for a greater radius on bends. The advantages were more important to us than the disadvantages-we selected the sixinch carriers.
Through local hospitals using pneumatic tube systems, we identified two vendors. These companies gave us user lists with the names of hospitals in other communities.
We sent out a short request for proposals, containing 26 questions, in November 1986, and the two vendors submitted their proposals the following month. Then, from January to August 1987, we conducted an evaluation of the vendors and made visits to user sites.
I telephoned a number of the vendors' hospital customers. In addition, several of us, including a nursing representative, called on hospitals in the area to see their pneumatic tubes in action.
The calls and visits did not show either vendor to be clearly superior to the other. Interestingly, hospitals that insisted on proper operational use and maintenance by their own staff were far more satisfied than those who were less strict about these matters. Those contracting with the vendors for maintenance support tended to complain more about downtime, which in some cases involved a long wait for the service representative to arrive.
Vendors are aware of this. They encourage support by the hospital's own maintenance department since the most common problems are not serious and can usually be corrected in short order by individuals who have a moderate amount of training.
We also learned in our research that most stoppages are caused by careless use rather than system faults. Typical mistakes include jamming too many specimens into a carrier, not latching the carrier correctly, allowing papers or bags to extend outside the carrier, and not sealing specimen containers to prevent leakage.
There were even occasional tales of employees who transmitted lunch or other contraband to friends via the tube system, and other inappropriate uses, This taught us that it is just as important for a hospital to manage users on its staff as it is to maintain the system properly.
We judged both vendors capable of providing a system of reasonably good quality, and both offered most of the features sought by the hospital. Our nod went to the company with the low bid-about $250,000 before add-ons. That vendor also had considerably more experience with computerized systems.
After several weeks of negotiation, we signed a contract for 21 stations in November 1987. Construction began in December.
We installed 16 initially (see Figure 1); most of the others awaited renovation of nursing units. The clinical laboratory's Stat receiving area has two stations side by side, enabling the system to keep operating if one station malfunctions.
The Stat area is linked to two stations in the outpatient collection areas, three stations in operating rooms, and single stations in the blood bank, emergency room, delivery room, pharmacy, intensive care nursery, neurosensory intensive care unit, surgical ICU, medical/surgical cardiac care unit, and the medical/respiratory ICU.
Each station is identified by two digits. Those beginning with numeral I send to station 10 in the Stat area; those beginning with numeral 2 send to station 20 in the Stat area. Dividing the system into two zones distributes the traffic and avoids overloading into one or the other lab station. A carrier can be sent to the other zone's station, but it will take longer to get there because the routing is more circuitous.
With the contracts signed, the major roles in the project passed to our hospital's facilities planning and construction management teams. Working from drawings that showed the location of plumbing and electrical lines, the facilities planning staff helped the vendor route the pneumatic tubing throughout the medical complex.
The tubing would run mostly through corridor ceilings to avoid disturbing patients. Although the system is fairly quiet, you can hear a whoosh as a carrier whizzes by overhead at speeds of 20 to 25 feet per second. At a station, the carrier rumbles softly as it approaches.
Prospective users formed a committee to prepare for introduction of the system. Each participant drafted procedures related to his or her department. For example, laboratory representatives wrote procedures for the receipt of carriers and for quality assurance through assessment of usage and documentation of problems. As the system's prime mover, the lab also developed operating guidelines for all users.
Maintenance wrote procedures for clearing carrier blockages and for cleaning the system in case of leaks. Nursing also wrote a set of protocols. All departments emphasized prevention of leaks, proper cleanup methods when leaks do occur, and the need to record such incidents.
Several discussions dealt with the types of specimens that could be sent through the tubes, as well as their priority (Stat or otherwise). Some hospitals allow any and all specimens (including cerebrospinal fluid and other body fluids, biohazardous or not) and any priority (Stat, routine, and in-between). Others have stricter policies, such as blood only and no bIohazardous specimens.
The advantage to blood-only is that leakage is very uncommon from vacuum-type blood tubes. I believe the exclusion of biohazardous specimens is questionable, however. Any specimen is potentially harmful.
Users agreed to send only Stat blood specimens, including those known to be biohazardous, during initial operation of the system.
All specimen containers would be placed in plastic bags. We excluded urine specimens and other body fluids from tube transport initially, because of the risk of leakage and contamination.
There were exceptions to the blood-only rule: The emergency room and the two outpatient collection stations could send any type of Stat specimen. These units weren't likely to have anything besides blood and urine, and there wouldn't be that many Stat urines (the ER does its own routine urinalyses). Since the outpatient stations are staffed with laboratory personnel, problems with urine container leakage would promptly be reported and corrected. The relaxed specimen policy would expedite treatment and speed patient flow in the ER and the outpatient stations, while permitting the laboratory to eliminate its half-hourly ER messenger service.
The vendor offered four kinds of foam liners to protect specimen tubes and cups inside the plastic bags. We passed over those with slits for tubes, indented shapes for cups, and corrugated construction, opting instead for thin foam sheets, which would let us transport the largest volume of material.
Training began when most of the stations had been constructed and tested by sending and receiving up to 100 dummy loads. The terminals are simple to use, and a vendor representative needed only 15 minutes at each station to explain what has to be done. All shifts were covered by the representative. The main points stressed during training were:
1. Make sure that specimen containers, especially urine cups, are tightly closed and bagged to prevent leakage into the carrier and that the request form is placed outside the bag.
2. Make sure the carrier is latched at both ends so that it cannot open during transit.
3. Select the correct receiving station number from the printed directory posted at each station.
4. Remove carriers from the arrival bin promptly.
Maintenance personnel staff the tube system's computer center around the clock, though they are seldom called into service. The computer signals an alarm if some difficulty is sensed, most commonly when too many carriers are left in the arrival bin at a station. To prevent damage to carriers when a bin becomes full, the computer takes the station out of use.
The computer maintains a log of all transactions, including routing of carriers. If a carrier cannot be located, the computer can tell us where it was sent. These data also can be used to discern traffic patterns.
We eased into operation of the pneumatic tube system last May by starting with one of the outpatient collection stations. That site put transmitting as well as receiving under laboratory control; in addition, the station had low Stat volume. The delivery room came on-line next because its staff members had expressed interest in beginning as soon as they were trained. There were no major difficulties, and the system gradually spread to the rest of the stations.
Some unexpected requirements came to light during this period. For example, we found that plastic bags with a zipper closure or plastic tie don't always prevent leakage. Just as some staff members can be careless about tightening the cap of a urine container, so too can they neglect to properly close the bag in which it is placed.
A contact at a neighboring hospital told us the staff there used heat-sealable bags, similar to the meat packaging in supermarkets. These worked so well that we were able to drop the restrictions on transport of specimens other than blood. The heating units cost about $75 each.
We wanted to let nursing units send blood gas syringes without ice to simplify the process at their end and eliminate a potential source of leakage. This required having ice in the laboratory receiving area to stabilize the specimens as soon as they arrived. Pending purchase of an ice machine in the next budget cycle, we were forced to borrow ice from the cafeteria and also made our own in the laboratory freezers.
Our pneumatic tube system is surprisingly headache-free. The few problems we have had were traced to operator error rather than system failure. The hospital staff has been very good about honoring the Stat-only rule and following the packaging guidelines.
We haven't done formal turnaround tii-ne studies, but we do know that at least 350 Stat specimens travel through the 4,000 feet of tubing each day, taking about a minute to get from the farthest station to the lab. We are saving the time and expense of having nurses, residents, medical students, and laboratory personnel deliver Stat specimens, at an average of 10 minutes per trip.
The system is also handy in reverse, when one of the floors needs a quick resupply of collection tubes from the lab. In all, there are far fewer interruptions in the lab, which means technologists are able to spend more time on testing.
Our pneumatic system will probably lengthen considerably in coming years. A hookup with the radiology reading room is under construction. Another nursing unit recently acquired a station, and three more are scheduled to come on-line soon. The pharmacy department also expects to expand its use of the system. Surgical pathology is thinking about installing an entirely separate point-topoint system to provide a direct link with the operating rooms.
All participants have been quite pleased to date. We feel the pneumatic tube has dramatically improved patient care while easing pressure and staff strain to meet Stat demands.
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|Publication:||Medical Laboratory Observer|
|Date:||Feb 1, 1989|
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