This week we took up residence at Centro de Salud in Santo Tomás, something less than an hour away from our place by car. It’s a lot smaller than the hospital – they do blood tests and treat some things but nothing major – but there’s a lot more work to do here because there are no technicians to be seen and as a result it seemed that inside every cupboard door in the laboratory there was another piece of out-of-service equipment. In total, over the four days (Monday we stayed at the hospital and fixed some blood pressure cuffs) I think we put 4 centrifuges, 3 microscopes, 3 nebulisers, 2 baby scales, 2 blood cell counting thingos and a thermostatic oven back in service, which I dare say is more than we would have accomplished at the hospital even despite our efforts to snatch each piece of damaged equipment out of the technicians’ hands.
Capillary centrifuges are turning out to be quite a confidence boost for us – we’ve fixed four so far by replacing the lining where the tiny tubes hit the wall with tyre inner tube. This includes the one from last week which we called them about to make sure was still doing alright, as the lady from the lab in Santa Tomás came to tell us that one we’d tested with her hadn’t quite been fixed after all. I felt awful at first because she said it was full with 24 capillary tubes and they’d all broken… we got a relief to learn, however, that the tubes that are used are in fact disposable, so it was ‘just’ their time that we’d wasted, and we wouldn’t have to improvise tubes anytime soon… a bit more lab experience and that probably would have been obvious to us, but we don’t look so bad next to the refrigeration technician who is kind enough to be (got roped into?) taking us around to different health centres in the region. I knew we had learnt some stuff about medical equipment during our month of training in Granada, but it became even clearer when, after being told that the tubes were breaking in the centrifuge, we were headed straight for gloves while the man tries to wipe the rubber clean with his fingers, cutting himself with blood-covered glass in the process We learn a lot of things from him, of course, we just have to warn him of things a few times because he’s less familiar with the equipment. He also does a great job of finding us lunch spots and introducing us to which pig will be Friday’s lunch.
One of the most interesting pieces that we’ve come across this week has been the sterilisation oven in the picture above. It was old enough (acquired 25 years ago) to have a mechanical temperature control system instead of what would these days be a much less exciting soup of barely serviceable circuits and sensors. When you select a temperature with the dial at the front, a tube with a bit of mercury inside gets tilted to the left based on the value. Inside the tube, to the left, there are two circuit connections, and if mercury is joining them then the circuit will be closed and the heating element will be on (this is the starting state regardless of temperature). As the element heats the oven, the mercury expands and eventually causes the tube to tip over because of its shift in centre of gravity. This will happen later if the tube was left-tilted a lot originally because of a high set point, and the effect is that the mercury doesn’t close the circuit anymore so the heating stops. Eventually the mercury will tip the vial backwards and heating will begin again, and the process will continue so that the temperature of the oven is maintained around about the set temperature. Our fix involved fixing a previous fix and making sure it didn’t suffer the same fate of getting cooked by (presumably) touching the mercury tube. We also adjusted the dial so that the readings corresponded to the correct temperatures again, which conveniently meant we got to spend ages watching the mercury make sparks as it tipped back and forth while we calibrated it.
My most excited moment for the week came from the first all-mechanical device that we’ve seen: a thing used for counting the types of blood cells seen under a microscope. I liked it because of how I originally had no idea how it worked, and wasn’t really certain that we’d ever be about to fix it! The problems that it had were that some numbers weren’t incrementing the total, some weren’t incrementing at all, and some weren’t resetting back to 0 with the others when you turned the wheel. For a good 20 minutes or so I was just absorbed by it, clicking away, but even once we’d figured out how it was supposed to work it was an even more interesting challenge to figure out why it wasn’t working correctly. For the numbers not incrementing, they were just missing springs so I put some rubber bands there instead. For the numbers not resetting back to zero, I still don’t know for sure the process of resetting but I suspect it is something on the inside of each wheel that gets caught at a particular number by a wiper attached to the shaft through them all. I guess for the numbers that weren’t working, the bit that gets caught was either worn down or loose.. I didn’t risk pulling out the shaft to try to fix it incase it all fell to bits, but you can just increment the broken number to 0 through incrementing the counter then turn the rest around to join it. The numbers not incrementing the total was the most interesting fix, I think – it turned out that the further away from the total they were, the more likely it was that the total would skip. There’s a bar below each of the buttons which will pull down the springs of the total count if any of the buttons are pressed. After a bit of poking around I realised the hole that the shaft permitting the bar to get pushed down goes through was enlarged through wear. This didn’t affect the counts of the buttons close to the total, but pushing the ones far away would lift the shaft a bit, and that energy loss was enough to make the total skip the count – by preventing the shaft from lifting with a cable tie the bar then pulled the springs of the total down far enough that it would increment like normal. Then I found out the method that increments the hundreds digit was a bit overzealous and would increment on the tens digit’s 8 and 9, meaning the total went 89-90-100-101. It was just from wear, and I had an idea of how to fix it, but it might have risked taking the tens digit out of action completely so I didn’t bother. Anyway, the scientist lady told me she doesn’t even look at the total much and counts in her head….
In terms of outside-hospital activities, there was some sort of event for the hospital staff this week that we were invited to and even got a special mention at.. Some María got cheated out of her title of Miss Hospital Asunción by another María. A birthday party or two at our house this week so a few nights off from pizza, and we made the trek to Estelli for the weekend to join up with our friends and do the Somodo canyon lazy river/cliff jumping that the home stay family of some of our friends runs, which was incredible.