Back on the Labor And Delivery deck for another 24-hour shift: 7 a.m. today until 7 a.m. tomorrow. I did a Friday-Sunday combo over the weekend; I was off on Saturday and Monday, so not a bad tradeoff. Things were quiet enough on Sunday that I slept all night, after a fashion.
“Sleep” while on call is not like real sleep – as any of you who do it can attest. It’s one-eye-open, when’s-the-next-summons sleep. The bed is never right; it’s always too hot or too cold in the call room. I have a pretty decent call room here, but I’ve slept in a few that wouldn’t have passed muster for Guantanamo detainees. I can always feel the warm, ragged, scratchy ache of fatigue at the back of my neck and the corners of my eyes, even after the quietest of nights in the hospital.
So far today I’ve helped with a Caesarean section and placed one labor epidural. Those I like doing; I’ve done thousands over the years, and laboring moms are always thankful when the searing discomfort of labor contractions fades away to something present, but not as threatening. Epidurals are generally low-risk, and not technically hard to do in most people, as long as you can feel hip bones and spinous processes. Those are the bony protrusions in a line down the middle of your back, down your “spine”, that you can see or feel when someone bends over.
Standing behind the intended epidural recipient, I feel for the iliac crests – the tops of the hip bones – on both sides, and I connect them in my mind with a horizontal line. I trace my finger vertically down the back along the spinous processes, making another imaginary line to connect those bony dots. Where those two lines meet is where I want to place the epidural needle, so that it finds its way between the spinous processes of the third and fourth lumbar vertebrae. At that level, the dural sac that contains the spinal cord is mostly empty except for nerve roots; the cord itself ends at around the first or second lumbar vertebra. I am looking for the epidural space, a plane between layers of additional protective coverings surrounding the dural sac. It’s not really a space until we fill it with something, but we take advantage of its presence as a way to deliver local anesthetic to the spinal nerve roots the coverings surround. Think of it as your hand, wearing several layers of gloves; we want to find a specific plane between those layers of gloves, with a needle, entirely by feel, without hitting the hand or penetrating the innermost glove.
I numb the skin and superficial tissue with local anesthetic, and advance the epidural needle while applying constant pressure to the plunger of a water-filled glass syringe attached to it. Haste makes waste here, but neither is undue dawdling appreciated by the person in labor. The epidural needle is thick enough that the sight of it has buckled the knees of more than one nervous father, and anywhere from 4 inches long and up. 4 inches is plenty for most patients; I try never to use the long ones, because six inches is plenty long enough to find a kidney, a spleen, a vena cava, or even an aorta. Trust me; each of those things has happened to someone, somewhere. Catastrophe is not my business, if I can avoid it.
Advancing farther, I hear, and feel, a gritty scrape as the needle tip penetrates the ligament that joins the spinous processes. My thumb is unable to push the plunger and squirt the water through the needle, because the dense ligament won’t “give” to allow the water to enter its substance. This is the “resistance”, whose “loss” with a whoosh of saline marks entry into the epidural space just beyond the ligament, as I transit its few millimeters’ thickness. It’s as if someone has opened from the other side a door I’ve been leaning against.
Once I’m in the space, I place a thin plastic catheter (medical-ese for a flexible hollow tube), thinner than a pencil lead, through the needle and into the space. The needle comes out – its job was just to guide the catheter – and the catheter remains behind. I tape everything into place, and start pushing dilute local anesthetic through the catheter. Our assumption is that the local anesthetic will spread throughout the epidural space, and travel within it to the nerve roots that exit the spinal cord. Those roots intertwine to form nerves that transmit electrical signals the brain and spinal cord interpret as labor pain. Continuing our hand-and-glove analogy, we want to fill the plane between gloves with local anesthetic, so that all the fingers are completely surrounded by it.
That’s all there is to it – when things go smoothly. My hands do the motions with little guidance from the brain, which is handy when you’re doing it at 3 a.m. The brain’s job is to detect when things aren’t right, somehow. Happily that’s uncommon.