When I first started my residency in the early 1970s, things were remarkably primitive by today's standards.
There were no ultrasound machines. Believe it or not, we would diagnose acute cholecystitis by history and physical examination alone. The only diagnostic tests we had were oral cholecystogram (OCG) and intravenous cholangiogram (IVC). For OCG, pills were taken the night before the test. If the cystic duct was patent, iodinated contrast would appear in the gallbladder and stones could be seen. Non-visualization of the gallbladder meant either the cystic duct was blocked or the pills were not absorbed (presumably due to inflammation, not necessarily of the GB) or the patient forgot to take the pills. The test was useless in acutely presenting patients. IVC was similar except the contrast was given intravenously. The common bile duct could be seen faintly unless the patient was jaundiced. It rarely showed stones in the GB.
There were no CT scans. We had to make the diagnosis of appendicitis by, you guessed it, history and physical examination alone. And since laparoscopic general surgery did not become common in the US until 1990, all appendectomies and cholecystectomies were done as open procedures.
There were no computers in any clinical departments or nursing units. Everything was on paper. The good news? There was no way to "copy and paste" progress notes. We had different colored paper for different sections of the chart, which made things easy to find. The bad news? Charts often went missing. Handwriting analysis rivaled that of archeologists deciphering hieroglyphics in Egypt. But paper charting was faster to do and easier to "leaf" through.
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Maybe the biggest change has been the advent of the Internet. In the palm of my hand, I can instantly access huge amounts of information formerly available only in print books and journals. To look up a paper, we had to use Index Medicus, an encyclopedic series of books listing every article by subject in most journals.