In its recent press release, the media relations department at Stanford University Hospital is touting the clinic’s pneumatic tube messaging system. The technology, which has faded away in most other industries with the advent of modern telecommunications, can still be highly efficient in large medical centers. The pneumatic highway is typically used to pass around clinical samples and orders between departments. While a lab may be within walking distance of patient rooms in small hospitals, it becomes increasingly distant as a facility grows in size. That’s what happened at Stanford, and now they have one of the largest such installations in the country. The pneumatic system is completely computer controlled and includes features like soft landings to prevent damage to any samples within the capsule.
It hosts 124 stations (every nursing unit has its own); 141 transfer units, 99 inter-zone connectors and 29 blowers. To help alert employees to the arrival of containers, the system has more than three dozen different combinations of chiming tones.
Such pneumatic tube systems date back to the early 19th century, when they drove the workings of postal services, department stores and other commercial businesses whose physical size demanded something faster than standard human pace. But those versions were usually designed to move paper. As computers and then the Internet made it possible to deliver data electronically without paper, tube systems lost their value for many industries.
But the technology endures—and thrives—in hospitals, thanks in part to more recent improvements in the delivery system. Originally, the tubes would arrive with a thud, a hard landing that could damage sensitive lab samples. Then in the late 1980s engineers figured out a way to control airflow to slow down the containers for a soft landing at their destination station.
At Stanford Hospital, before 1993, a team of about 20 people had the job of transporting the multitudes of tissue, medications and documents. However, the increasing size of the hospital, and the addition of two adjacent buildings—the Blake Wilbur Outpatient Clinic, the Stanford Cancer Center and Packard Children’s Hospital—made the tube system option the most modern solution.
Depending on the diameter of a tube, cylinders can reach speeds of up to 25 feet per second, about 18 miles per hour, far faster than any human could ever manage.
It was also a question of best use of employee time, if, as often happened, a courier wasn’t available when a specimen needed to get to the lab. Having a nurse leave a patient’s bedside for a minutes-long run to the lab made no sense.
Reliable speed is crucial when the system carries blood products, some of which are temperature-sensitive and, by regulations, must be discarded if not properly maintained.
Leander Robinson, the hospital’s chief engineer, commands the system from a small basement office, where computer monitors light up every time someone puts a container in a chute, types in a numerical address and presses the "send" button. The screen displays a tiny icon that reflects the container’s travel through various switches and transfers, but it moves so quickly it’s actually hard to track its passage. Even during the heaviest flow through the system, between noon and 2 p.m., a container can cover the longest start-to-finish distance—1,500 feet—in less than three minutes.
The system has a complete set of checks and balances, sensing where containers are needed and sending them. Some departments, such as the operating rooms, have dedicated lines that guarantee them a straight shot to the lab.