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Just like practicing anesthesia: “Hours of boredom separated by seconds of terror”.
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I’ve been fascinated with anesthesiology ever since reading an encyclopedia article about it when I was a kid (maybe 8 or 9 years old). From a patient’s perspective, it’s kind of scary…your life is literally in the hands of the anesthesiologist. Of course, there are horror stories about an anesthesiologist administrating the paralyzing agent, but not the sedative, and the patient feels everything during the surgery (I hope that’s an extremely rare occurrence). I’d love to hear an anecdote about when you experienced one of those “seconds of terror” situations. I bet you have some great stories to tell.
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One of the Rules of The House of God
In an emergency, take YOUR OWN pulse first!
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Such awareness is extremely rare and, barring outright gross errors, is entirely preventable. Among those operations which require general anesthesia, the large majority do not require flaccid paralysis; in most of them, then, only mild relaxation is needed - so, in the unlikely event the patient retains some degree of consciousness, they (sic) can move to signal a problem to the anesthetist. Probably the most common setting in which this rare event - called “intra-operative awareness” - was open heart surgeries with cardio-pulmonary bypass and hypothermia, where full paralysis is required. Most patients (again, very few in number) reported that while they had some degree of awareness, they were not wide awake, but sedated. Further, most often they reported that, though it was indeed unpleasant, there was little or no pain because open heart surgery usually involves what would otherwise be a large overdose of fentanyl, a very potent analgesic. The respiratory depression responsible for so many deaths nowadays among addicts, is not an issue, since all these surgical patients are intubated and ventilated throughout and for some hours after the procedure ends.
In addition, standard of care suggests use of a processed EEG on every patient in whom relaxants are used. This is simply a set of electrodes adhered on the skin of the forehead, which displays a number correlating well with consciousness or of lack thereof. Its use makes a rare event nearly impossible.
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Interesting that they did not have to dump fuel.
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Thanks for the detailed explanation, CW. I’m happy to know that such cases of intra-operative awareness are rare. I’ve been under general anesthesia 3 times in my life and I had complete confidence in my anesthesiologists each time. It’s comforting to know that during a surgery, there’s another doctor in the operating room whose sole responsibility is to monitor and ensure the well being of the patient. We’re very lucky to be living in modern times!
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Makes me think about John’s recent posts on reading brainwaves here and here—maybe we’ll have even better ways of determining the degree of consciousness in the near future.
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Here is video from Juan Browne (blancolirio) posted three years ago after the Boeing 777 dumped fuel on Los Angeles in an engine-out return to LAX. In the explanation, which starts at 3:30 in the video, he says that the Boeing 767 and 777 can land when loaded all the way to maximum takeoff weight as long as the runway is long enough and has suitable conditions (e.g. dry) for a single engine stopping distance. He says this is around 6,000 feet. (The runway in Prague is around twice that long.) After an overweight landing, maintenance has to do a “heavy landing check” on the plane, but he describes that as relatively minor (2 to 4 hours) compared to the work in replacing an engine.
From Boeing: “Overweight Landing? Fuel Jettison? What to Consider.”
Landing overweight and fuel jettisoning are both considered safe procedures: There are no accidents on record attributed to either cause. In the preamble to Amendment 25-18 to FAR Part 25, relative to fuel jettison, the FAA stated, “There has been no adverse service experience with airplanes certificated under Part 25 involved in overweight landings.” Furthermore, service experience indicates that damage due to overweight landing is extremely rare.
Obviously, landing at weights above the maximum design landing weight reduces the normal performance margins. An overweight landing with an engine inoperative or a system failure may be less desirable than landing below maximum landing weight. Yet, delaying the landing with a malfunctioning system or engine failure in order to reduce weight or jettison fuel may expose the airplane to additional system deterioration that can make the situation worse. The pilot in command is in the best position to assess all relevant factors and determine the best course of action.
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The Boeing airplane maintenance manual (AMM) provides a special inspection that is required any time an overweight landing occurs, regardless of how smooth the landing. The AMM inspection is provided in two parts. The Phase I (or A-check) conditional inspection looks for obvious signs of structural distress, such as wrinkled skin, popped fasteners, or bent components in areas which are readily accessible. If definite signs of overstressing are found, the Phase II (or B-check) inspection must be performed. This is a much more detailed inspection and requires opening access panels to examine critical structural components. The Phase I or A-check conditional inspection can typically be accomplished in two to four labor hours. This kind of inspection is generally not a problem because an airplane that has returned or diverted typically has a problem that takes longer to clear than the inspection itself.
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