Five Quarts_ A Personal and Natural History of Blood - Bill Hayes [90]
Once blood is removed from the body, the cellular life spans plummet. Forestalling the death of blood is the major clinical function of any modern blood bank, although, granted, you wouldn’t find such dark phrasing in an annual report. A blood bank gives the impression of being less a bank—as in, a place to stockpile—and more a hospital, wherein blood is on continual life support. I quickly came upon this realization during my tour of the main branch of Blood Centers of the Pacific, a state-of-the-art facility here in San Francisco, where I’d come to see how blood products are made. As Richard Harveston, the director of hospital services and my genial host, explained to me, blood must be carefully housed, nourished, and tended. “Blood is a living tissue,” he said. And therein lies the challenge.
“One of the greatest advances in blood banking came in the early 1970s with the advent of plastics,” continued Richard, in what at first seemed like narration from a different tour.
“Plastics?”
“Yep, just like that guy says in the movie The Graduate: ‘Plastics.’ ” He smiled, adding, “Before technology for making plastic bags was perfected, blood was drawn in glass bottles,” which caused a lot of headaches. Bottles took up lots of storage space and trapped air, fostering bacterial contamination. By contrast, plastic bags provided a slew of advantages, including being virtually unbreakable, lightweight, airtight, and malleable. In addition, Richard explained, “Plastics made possible the era of component therapy.” This last sentence rose to a deliberate crescendo. In component therapy, blood is separated into its various parts, which then become highly efficient, targeted interventions, such as the present-day replacement therapies for hemophilia. Cindy Neveu’s cryoprecipitate, although a dinosaur when compared to other treatments, would also fall under this heading.
We were standing on the periphery of the blood center’s collection area, where five donors were giving blood. To illustrate the procedure, Richard pulled out a “blood collection set”—three connected clear plastic bags (a large and two smalls) trailing a tangle of tubing. The whole mess looked like a jellyfish, the kind of thing a kid on a beach would poke with a stick. “Blood flows into here,” he said, pointing to the primary collection bag. This pouch already contained a small mix of fluids: an anticoagulant, a phosphate to maintain the pH, and a nutrient to keep the blood cells alive. He then traced the tubing to the second bag, which would later be used during the blood processing phase to hold the plasma, and to the third, a pouch for platelets. “If you’ll notice here,” he said, inviting me to feel the last pouch. “This is a different plastic, this has a different porosity,” allowing gases to pass in and out. “Just like we do, platelets have to breathe.”
Leaving behind the homey atmosphere of the collection area, Richard and I entered the factory-like environment of the Component Lab and stepped around what could’ve been a beverage cart from an airplane, heaped with fresh pints of whole blood. It looked kind of disorderly, truth be told, but each unit, Richard hastened to point out, was bar-coded, its every movement through the facility tracked. For each bag here, a tubette of the donor’s blood had also been collected and affixed with a matching bar code. These samples were already on their way to a lab in Arizona, where each would be comprehensively tested for HIV, hepatitis, syphilis, and so on, and so forth.
Within six hours of being drawn, a large portion of the pouches are spun in a centrifuge. The technician working this machine allowed Richard to demonstrate. The centrifuge, whose interior is chilled to just above freezing, has six pewter buckets. He stuffed each with a bag of blood, the one full and two empty pouches sandwiching nicely. Blood naturally separates, Richard noted, but this device speeds up