One weekend when I was sixteen, my family was loading up the
car to go visit my grandparents. As I climbed into the backseat, a stabbing
pain in my chest hit me. My left shoulder cramped and my left arm was painful
to move. I told my dad about what
I was feeling, and we both dismissed it as a random cramp. Five minutes later,
the pain was worsening and I wondered if I was having a heart attack at only
sixteen years old. We decided to swing by the emergency room just to be sure.
Come to find out, my left lung had spontaneously collapsed.
As doctors with x-ray machines and pokey things began to swarm around, I looked
at my unshakeable father standing in the corner of the room. He was looking at
me and shifting his weight from side to side, with a furrowed brow and crossed
arms. This meant he was confused.
It just so happened that my best friend’s father is a
pulmonary specialist. As the drugs began to cloud my head, I watched Dad pacing
outside of the room with a cell phone to his ear, talking to my friend’s dad,
Dr. Liendo. A man with a well-placed sense of humor, he told my dad that I was
experiencing a “flat tire,” and after several minutes of conversation, my dad
was clear on what was happening.
One of the most misleading physiological comparisons is that
of a lung to a balloon. (If I could legally encourage you to deface every
balloon/lung demonstration you see at science education centers, I would). A
balloon inflates by air being forcefully pushed into the vacant space inside.
This is a positive pressure system, since the balloon inflates by air being pushed into it. But lungs do not work
like this. They work on a negative pressure system, meaning that air is pulled into the spongy tissue that is
the lungs- not an empty cavity like a balloon. What does the pulling, then?
Lungs are not muscularized- but your chest cavity is.
Your diaphragm is the muscular floor of your chest cavity.
When it is relaxed, it bows upwards. When it contracts, it straightens out and
lowers down- making your chest cavity bigger and therefore expanding the lungs,
pulling air in. Ahhh, yes. Your lungs are attached to the walls of your chest
cavity. At least they’re supposed to be.
They are attached by a thin layer of moisture called the pleura (imagine two sheets of plastic
being stuck together when they get wet). Should this adhesive moisture break
contact with the lung surface and the chest wall, air will leak from the lung
into this pocket, forming what’s called a “bleb” between the lung and chest
wall. Sometimes, the bleb heals and
the pleura reseals itself. No harm no foul.
 |
| Left: A tiny bleb at the top of the lung Right: The lung continues to collapse |
Other times, the pleural break is large enough that the lung
continues to pull away from the chest wall and collapses. Your diaphragm
continues to expand the chest cavity, but the lung is a pathetic, shriveled,
useless raisin. (This hurts a lot). This can be fixed by inserting a chest
tube so that it rests in the chest cavity, allowing the air pocket to escape
and the pleura to reseal. If it’s a stubborn one, they might even hook it up to
a vacuum and suck it out.
Dr. Liendo likened this system to a tire (the chest cavity)
and the innertube within (the lung). To this day, Dr. Liendo tells me that I am
allowed “no more flat tires.” I will always be grateful to him for unfurrowing
my dad’s brow that day.
And if a rash of vandalism against balloons being used as
demonstration lungs breaks out after this, I will not be upset.
