Ode to a Body Plethysmograph
The origins of this story are in a recent posting by my friend Dani to his Facebook page. He related his experience in a Gold Coast body plethysmograph. But I have to start my narrative way in the past.
I had a good friend in high school called Bernie Lee. He was a year ahead of me, but that didn't matter much. He was a electronics whiz. He could make almost anything out of these little components. I didn't understand everything he was doing, but enjoyed building things with him. I had intermittent wipers on my Hillman Hunter GT before the Ford Motor Company even knew they existed.
This was so much fun that I decided I would make my career in electronics. I thought the path to this was Electrical Engineering at the University of New South Wales. So, even though my mother was certain from the day my brother was born that he would be a physician and I a solicitor, I entered the Faculty of Engineering. She questoned how I would ever make a living ... a very common post-Holocaust concern.
Very soon I discovered engineering was not for me. I scraped through the first year. It was rather boring, but first year engineering then was just first year science with the most uninteresting subject in the world, General Engineering, thrown in — all engineering students followed the same syllabus in first year.
One of the things they taught in first year mathematics was computer programming. In those early days all they had was Fortran. And how did you enter your program into the computer? The standard way of doing this was via eighty column punched Hollerith cards [the very same which IBM provided and serviced for the S.S. in Auschwitz to track their inmates]. Each column on the card represented a single character, made up of variously placed and numbers of holes in the column. That was for the machine to read. Humans, in order to check that the card was correct, could see the character printed above the column.
Normal people produced these cards by typing into a card punch machine, a typewriter device which produced cards instead of paper. As there were thousands of students in first year maths, and not many punch machines — they were big and expensive — on campus, we had to buy cards that were covered with little perforated oblongs, forty across the card. You were supposed to write what you wanted on the top of card, in pencil, and then take a bobby pin to push out the relevant perforations, thus creating the required holes. You had a table indicating which holes to punch for which characters. Apart from having a lecturer who I don't believe knew too much about programming the beasts, he certainly had no clue how to impart any information he held on the subject to his mere mortal students.
I never managed to write a computer program that entire year.
I suffered thoughts of doing dentistry but could only get into Melbourne University. I really wanted to study history, one of my loves today, but feared my mother might comit suicide. Even I then realised there was no career path in that. In the end I made the mistake of going with the flow and started second year engineering. Again fairly standard science subjects with a course in Mechanical Engineering. That was the real killer. I dreaded each lecture. I learned one thing in engineering school. That I did not want to be an engineer! Engineers solve practical problems using methods developed by scientists. You need to see the world in a certain way if you want to be an engineer, if you want to solve engineering problems. I was too much an artist and too scientific to want to, or even be able to force my brain into this mold. I also found out that while I had wanted to work in electronics, electronics was just one of the subjects you studied in fourth year.
I was out of there.
One of the truly brilliant things I did discovered in second year was the punch card machine. What a revelation. No bobby-pins, no perforations, a whole eighty characters per card, which generated one line of program (or data). And then, I found out the most closely guarded secret of all — that the School of Electrical Engineering provided a typing service for its students' programs. You just wrote out what you wanted and an hour or two later, a fresh deck of cards awaited. Now I spent hours programming Fortran. What a ball. This was what I wanted do — forget Bernie's little gadgets — computer programming was empowerment!
I finished my B.Sc. degree in Computer Science with honours in 1974. I even achieved this in the minimum time of four years. I suffered no penalty, other than to my brain and personal esteem, by having wanted to be a "ginger beer".
I now wanted to do a masters, a doctorate — I was hot. My first love was Artificial Intelligence, turning a box of silicon into a fellow, thinking human being. Cutting edge stuff. My first masters thesis proposal was to create a machine who could play — and win — a game of Stratego. Forget intermittent wipers — by now these were now standard on Fords — I was producing a thinking machine, a smart beast.
Why Stratego? In those days, everyone, including me for my honours thesis, was working on chess. To me back in 1974, ten years before Deep Blue versus Kasparov, chess programs were passé. In chess you can see (though not know) what your opponent is doing — all board information is revealed to both players. In Stratego you may know where your opponent's pieces are currently situated, but you do not know the rank of any piece. It is for you to learn this during the course of the game. You must continually improve your imperfect information. Far superior to chess.
But I needed to work too, partly because you need to occasionally come down from the ivory tower to see how the world is using our clever boxes, and partly because I was sometimes a little hungry.
My first job was for a professor of Pulmonary Function at Prince Henry Hospital in Sydney. As a teaching hospital, this was still part of the university and was considered an academic position. So I still retained one foot in the university's door (while concurrently working on my masters).
My task was to automate the functioning of a body plethysmograph. This device, into which a human is locked, is used to calculate a patient's lung volume — TLC, Total Lung Capacity. It is actually quite a simple device, using Boyles Law to make the calculation. Robert Boyle taught us, back in 1662, of the proportional relationship between the absolute pressure and volume of a gas, if the temperature is kept constant within a closed system: symbollically represented P1V1=P2VP2. Locking our specimen into an airtight box, we know the values of three of these variables — the fourth, lung volume, is the only unknown and falls straight out. Even I could write that computer program.
The only catch is that Boyle requires the system to be "closed", i.e. no air can escape. Breathing is escaped air. So our plethysmograph was a small, airtight, wooden box. Back in my day it was super claustrophobic, the box was barely big enough for a middle sized man, with a transparent plastic cone on top through which the patient could see the world if he was tall enough. But not too tall as his head would not quite fit inside. I refused to be measured up. Claustrophobia? — a one-man Russian tank looked far more comfortable.
In the dome there was a short pipe through a hole, with a mouthpiece on the inside. The victim could breath through this opening. When we were ready to take our measurement, we pressed a little button, closing off the mouthpiece, closing the system for Mr Boyle. We had to work quickly because we could easily suffocate the victim were we too slow. We could let her turn a little red, but never blue. At the first faint shades of blue, we'd open the shutter to allow a few breaths and then close it up again.
What worried me was that my computer program was supposed to close and reopen the mouthpiece under computer — read my program's — control.
From Dani's photographs I see they now make the plethysmographs transparent and relatively roomy. I'm sure that helps a lot in keeping the victim calm. We had to tie people up, hand and foot, chuck 'em into the box, and lock the door, tight, hermetically. The more energetic sacrifices would bang their heads on the door trying to escape. Fortunately the thing was so well sealed that we didn't hear even a wimper. We thought they were having a ball, banging their heads in beat with the Radio 2FC music we played in the lab. Of course we had the cavalry standing by to let them out. Before the door was unlocked we were well out of there! Now those were fun days!
And you should have seen the computer the prof had. Digital made really good machines, dominating the mini-computer market with its various PDP-11 computers. PDP-11/70s were a classic. But my prof lived from a small grant. He bought — who let him do it, really? — a PDP-11/10, basically a big drawer full of rattling electronics. It ran an operating system called CAPS-11, CAssette Programming System. The computer's only storage device was a pair of cassette drives. You all remember how unreliable cassettes were for music, how tape tangled itself up in the works and you had to rip it out like spaghetti and then splice out the bits that were too mashed to use? Well this was the same. All your hard programming work squashed between the record and playback heads. What was Digital thinking when they released this product? To be honest, I guess they didn't sell too many as this was the only cassette machine I ever came across and I've used many PDP-11s.
No-one in the hospital labs worked too hard. Because we were academics, we didn't have to bundy in and out each day. There was an honesty attendance book at the entrance to the building. Our work hours were officially 9:00 a.m. to 5:00 p.m. We were granted an hour off for lunch and fifteen minutes for each of morning and afternoon tea.
On my first day, I arrive to work at 9:10 a.m. I see the sign-in book. Boy, I am really late. These academics are keen. They love their jobs. The times on which the last people arrived were:
I'd better get here earlier tomorrow. I sign in:
9:11 Menachem Kuchar
About thirty fellow workers came by my lab on that first day. I thought they are so nice here, welcoming the new fellow on my first day. But all these nice people had their daggers drawn as they entered our lab. "When you arrive tomorrow, no matter what your watch, or the clock above the book, says, you write the same time as the guy above."
I left on that first day at 4:57 p.m. When I arrive at the book, the time recorded that the last person left was 5:17 p.m. My, my, how time flies when you're having fun and performing cutting edge research.
Our professor's office was down the corridor a bit from the lab, across the hallway. We were lucky. He had had polio as a child and walked with a pair of crutches. So we always heard his approach and knew when to look busy.
I shared this lab with a doctoral student, Clifford Ng, from Hong Kong. I never found out how to pronounce his surname, and had he told me his real first name, I'm sure I would have had the same difficulty with that too. In fact it took me a while to familiarise myself with his English at all. He was soft spoken and a Baptist, which shouldn't have any bearing on this story, except for the following incident.
We had many philosophical and religious discussions. They were quite interesting and stimulating. He knew I was Jewish, though I'm not sure if it had anything to do with the kippa on my head. We discussed the necessity, methods of ritual immersion and western religions in the East, and more that I don't recall any more.
One day I noticed him staring at me in a strange manner. I ignored this first, but then said, "Clifford, what are looking at."
He was looking at my face. "I don't understand", he said.
"What don't you understand?"
"You're a practising Jew — I can't see your circumcision!"
"You are supposed to circumcise your foreskin, and it is smooth", he said, staring at my unwrinkled, unscared forehead.
The other thing we measured in our lab was lung pressure. This is quite simple to do really and I'm not sure how automation could help much. You just need a little balloon sitting on the outside of the lung. How do you achieve that? Quite easy. You deflate a small balloon, put it on the end of a rubber tube, drop the tube into the oesophagus to a point where it sits on [the outside of] the lung itself, inflate the balloon and measure the pressure in the tube. We had the tube marked out: tall man, middle sized man, small man, short lady. Clifford would drop a spot of anaesthetist into the victim's throat and I'd shove the balloon up his left nostril, curve it around the back of the nasal cavity, and carefully manoeuvre it into the oesophagus rather into the lung via the windpipe. We push it into the nose until the relevant outside marking ends up on the edge of the nostril. With a syringe you add a bit of air, take the measurement, and pull it all out again. Simple.
Our professor was a consultant to the Navy. It was a way for him to get guinea pigs for his research. We'd often get volunteer sailors coming in on Friday afternoons. In exchange for agreeing to us tickling the back of their throat, they got an early mark for the weekend. Almost invariably the sailors, men or women, would have a liquid lunch on the way to our lab. And inevitably they would chunder all over the lab as the tube went around the bend.
There was also the story of a new H.P. spirometer the hospital bought for measuring Forced Expiratory Velocity (FEV), the amount of air you can express in 1 second. Pre-electronics, the spirometer was quite a simple device. There was a mouthpiece at the end of a tube, the other end connected to a drum wrapped in graph paper. Blowing through the mouthpiece spins the drum, the harder you blow, the further the drum rotates. A stationary pencil on the outside of the drum indicates the FEV values.
The other pulmonary professor in our hospital found some money to buy the new machine. Out of the box and everyone has a blow. Values around 11+ are typical for FEV1. My turn. I pucker up — 12.50 — the day's record! Do it again Menachem. Breath in hard, pucker up even more — blow the billio — 12.50! Oh come on. OK Menachem do it a third time. Ditto. 12.50!! No-one could believe it. Three times in a row, the same reading, to the 2nd decimal place.
Has anyone looked at the accompanying manual? Oh that's no fun. They just took it out of the packaging and started playing with it. In the interim they give me the old, mechanical model — 14.8! That's more than almost anyone has ever achieved here, except for the professor himself who scored a massive 15.1!
And the manual, "Maximum measurable velocity: 12.50". The dumb machine was designed for sick people, not athletes like Menachem :-)
Menachem Kuchar, 14th April, 2010
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