Posted on 12/01/2022 8:20:42 PM PST by ConservativeMind
Giving patients excess levels of oxygen during surgery is associated with a higher risk of subsequent kidney, heart, and lung injury, finds a large U.S. study.
Although the absolute risk remains low, this study suggests it is time to reconsider the liberal use of oxygen during general anesthesia, say experts in a linked editorial.
Oxygen is routinely given to almost all patients undergoing surgery with general anesthesia to help prevent hypoxia (dangerously low oxygen levels), and the World Health Organization recommends liberal use of oxygen to reduce the risk of infection.
During surgery, arterial blood hemoglobin oxygen saturation (SpO2) is continuously measured, enabling doctors to adjust the dose of oxygen to a target level. A normal SpO2 is 94-95%. Giving oxygen in excess of that required to saturate hemoglobin—known as supraphysiological oxygen—is common.
Supraphysiological oxygen can harm the body's cells and tissues, but the clinical relevance of these effects during surgery remain uncertain, and previous trials have not been able to detect any meaningful effects on organs.
After accounting for baseline factors and other potentially influential variables, increased oxygen exposure during surgery was associated with a higher risk of organ injury.
For example, patients at the upper end (75th percentile) of oxygen levels had 26% greater odds of acute kidney injury, 12% greater odds of myocardial injury, and 14% greater odds of lung injury compared with patients at the lower end (25th percentile).
Patients at the 75th percentile of oxygen levels also had 9% greater odds of stroke and 6% greater odds of 30 day mortality than patients at the 25th percentile.
However, patients at the 75th percentile had a slightly shorter length of stay compared with patients at the 25th percentile, an effect unchanged after excluding patients who died before discharge.
These are observational findings, so can't establish cause.
(Excerpt) Read more at medicalxpress.com ...
True, this.
Otherwise, we wouldn't be supplementing with a bunch of antioxidants.
(Yes, I know, oxidation does not always involve oxygen, we're really talking loss of electrons.)
This sounds like a bunch of BS to me. They are putting people in hyperbaric chambers for cancer, Lyme disease etc with good results.
During my second cataract surgery they gave me a little too much oxygen because of my asthma. I had a bad sore throat for a day. No big deal.
So if you get the TIVA method of anesthesia.. vein versus mask..do they still do oxygen mask on you..seems like they would still need to be Able to regulate.
These people who get serious Covid and end up in hospitals....are often seen getting ‘extra’ oxygen. Makes one wonder if their ‘long-Covid’ problems don’t all lead back to this same issue.
When I first became a firefighter over 30 years ago, we used “demand valve” masks delivering pure oxygen directly to patients who we were performing CPR on. We were able to pink up even people who had been down for quite a while, and with shocks and drugs we often got their hearts to start pumping again. We called this “a save”. This was very satisfying because we thought that we were helping them.
The problem which was noticed by medical providers who took care of the people we delivered to hospitals is that nearly all of the people who we used demand valves on were dead within a few days. People who received CPR using mouth to mouth and “bag valves” which deliver oxygen through a face mask by squeezing the bag had much better outcomes and survival.
Because people refused to believe that the demand valves were actually increasing mortality, despite ever-increasing evidence... we continued to use them for years. Who knows how many people whose lives our bull-headed attitudes killed. It is good to be skeptical, but some of the time our firmly held beliefs turn out to be wrong.
This is correct. Free radical damage occurs at oxygen inpired concentrations of 60% or greater.
You can believe every word of it. We have know for quite a long time that oxygen contents higher than FiO2 of 60% free radical injury. We always strive whether intraoperatively or in ICU to limit oxygen inspiration to under these levels. The injury is time dependent as well. The longer the time the worse the injury in the organ systems.
Yea you get oxygen during TIVA. In fact it is likely you are intubated during TIVA as inhaled ether anesthesia
Medical malpractice likely kills more people annually that the coof ever did.
I’ve had 5 major surgeries. Before my most recent one (an appendectomy) a CAT scan/MRI (forgot which) report casually noted “evidence of lung damage” and referred to prior surgeries and anesthesia as the likely cause (none of my surgeries had anything to do with my lungs or were near the lungs at all).
It took 10 replies but you won. Free radicals.
My anesthesiologist was the chief of the dept. and director of the OR as per his bio. When he came in to talk to me he said he was in charge of the operating room and directs the surgery to ensure all goes well. ..and was well experienced with malignant hyperthermia.
I felt comfortable that no surgeon was going to push him around. Might have been false sense of security but at least I didn’t feel like someone was going to screw up.
I have always wondered what going under might do to the brain in terms of alzheimers...especially if the patient is older
When I first woke up I recited the alphabet out loud and counted backwards from 20 to try to ensure my brain didn’t get jacked up..which in reality probably had no bearing because I could have been saying gibberish and my mind could have said yeah..you are saying it correctly.
The nurse probably wondered if I had gone crazy..lol
That is an amazing story.
Thank you for sharing that. It would not have been intuitive.
Fascinating.
Acutely ill, overweight patients, and patients with cardiovascular disease (prone to MI and stroke) are generally given higher concentrations of oxygen as a rule. Not to be reckless, but to ensure adequate oxygen saturation.
In this study, fully one half of patients were classified preop as ASA category 3, meaning "severe preexisting systemic disease". This factor was not adequately controlled in the study.
The kind of surgery makes a huge difference in how much oxygen is required to maintain good saturations; it was not controlled here.
The measures of "kidney damage" and "myocardial damage" are too sensitive, poorly controlled (meaning only the sickest patients had postoperative creatinine and troponin drawn), and, as far as this paper tells us, the transient postoperative increases in creatinine and troponin were unrelated to long term kidney or heart damage.
Lastly, you always need to weigh the risk versus the benefit of a therapy.
It has been shown, for instance, that using high (excess) oxygen concentrations is very effective at reducing postoperative surgical wound infections. If you've ever seen or had a postoperative wound infection, you know that it is a big deal.
That finding was via a controlled prospective study (N Engl J Med 2000; 342:161-167), not a retrospective study like this one.
This study opens a lot of possibilities for further, well-controlled, prospective, hopefully blinded, studies. But it does not show that 'excess oxygen', as they define it, is necessarily harmful.
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