Anesthesia: Muscle relaxants - risk of respirat complication

[gerald]

I find this concerning. Basically any operation that you need anesthesia for can damage your breathing.  If you lungs are not already compromised the effect may not be noticeable. However, if you are already at that critical point it could be serious

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Anesthesia drugs: Muscle relaxants increase risk of respiratory complications

Date: September 17, 2018
Source: Technical University of Munich (TUM)
Summary:Muscle relaxants are a necessary part of anesthesia during certain major operations. Studies have, however, hinted at respiratory risks connected with these drugs. A major new study has confirmed the association between use of muscle relaxants and respiratory complications and assessed the chances of the current avoidance strategies.

Muscle relaxants are a necessary part of anesthesia during certain major operations. Studies have, however, hinted at respiratory risks connected with these drugs. POPULAR, a major prospective observational European study supported by the European Society of Anaesthesiology (ESA) and led by the Technical University of Munich (TUM), has confirmed the association between use of muscle relaxants and respiratory complications and assessed the chances of the current avoidance strategies.

Anesthetics make patients unconscious during an operation and prevent them from feeling pain. Muscles, however, are not paralyzed by these drugs and may still move. "To prevent this, we also use muscle relaxants or, more precisely, neuromuscular blocking agents," says Professor Manfred Blobner, an anesthesiologist at TUM's Clinic for Anesthesiology and Intensive Care.

"These drugs are particularly needed when operating on a patient's chest or abdomen. They are also used to protect the vocal cords from injury when a tube is placed in the airway to allow artificial ventilation," says Blobner who is the chair of the POPULAR steering committee, a multinational group of researchers from TUM School of Medicine, Karolinska Institutet, University Hospital of Bonn, Amsterdam University Medical Center, Université de Lorraine Nancy, and the Faculty of Medicine University of Liverpool. The prospective observational POPULAR study collected data from 22,803 patients of 211 hospitals in 28 European countries.

Results confirm risk for patients

The first results from this study are now being published in The Lancet Respiratory Medicine. They confirm what earlier studies based on pre-existing data had hinted at: The use of neuromuscular blockers during general anesthesia is associated with a significantly increased risk of several respiratory complications after surgery.

The most common complications involving the respiratory system were a reduced capacity of the lung transiently to absorb oxygen (5.2%), and infections of the lung and respiratory tract (2.5%). Roughly three quarters of all patients (17150 people) were treated with neuromuscular blocking agents. They were shown to have a significantly higher risk (+4.4%) of developing any type of respiratory complication.

Neither monitoring nor drugs lower the risk

The study did not look into how the use of muscle relaxants might cause the negative effects. Earlier studies have shown that even small amounts of muscle relaxants remaining in the bodies of patients could be responsible for some of the complications. The data from POPULAR however show that established techniques used to avoid residual neuromuscular block do not lower the patients' risk of pulmonary complications.

Neither drugs reversing the effects of the muscle relaxants nor monitoring of neuromuscular function during anesthesia to make sure that the muscle function is completely recovered did change the respiratory outcome. The researchers point out that this does not mean that these measures are unable to reduce residual paralysis but they must be used correctly. There may be flaws in the way these measures are implemented as well as other unknown causes for the complications.

Blocking agents remain important and helpful

"It's important to note that neuromuscular blocking agents have made surgery considerably safer and more effective since their introduction several decades ago," says Professor Blobner. "We have constantly refined both the drugs and the techniques used. Many operations would not be possible without them. Still, the results from POPULAR raise important questions."

Blobner and co-authors are planning to implement more targeted studies to identify the underlying mechanisms behind their findings. "Based on our results, we believe that patients undergoing minor surgical procedures that do not necessarily require neuromuscular blocking drugs might benefit from avoiding them. Using devices like laryngeal masks for anesthesia instead of tracheal tubes that go past the vocal cords could prove helpful as well," says Blobner.

www.sciencedaily.com/releases/2018/09/180917111633.htm?

[gnott]

Good article.

Everyone needs to know this, especially as I am surprised by the statement "Studies have, however, hinted at respiratory risks connected with these drugs
." I thought this was general knowledge, and more than a hint - an absolute known risk. At least it has been with my medical people since 2004.

There are many invasive procedures (colonoscopy, endoscopy, prostate biopsy, etc.) [Old Man Stuff, Smile] I've avoided because my doctors discussed the possible risk from anesthesia AND muscle relaxants. I've been lucky in the sense - every occasion when such a test was warranted - time proved out it wasn't necessary.

I told them if would become necessary a leather strap and Jack Daniels would probably work as well - but they haven't seemed agreeable. However that is only what I would expect - I remember from college and later medical students and doctors were in general very slow to find their wallets when it was their turn to buy a round. Too cheap to stand me a drink.

[skate4life]

I am bothered by this particular article for its lack of specifics. I feel a lay person might well be scared by the article and have increased anxiety unnecessarily. I gave anesthesia for 40+ years so I feel qualified to judge this article as posted. I would need to see exactly how they monitored the muscle relaxants used - both dosage administered, and dosages of reversal agents used and how long they monitored the patient. While the monitoring device may show return to normal, the body is still metabolizing small amounts and there are some patients with deficient pathways to metabolize all medications in the 'traditional' window of time.

Secondly, each patient has flora in their nose and mouth that is unique to them. So what bacteria did these patients have with their post-op lung infections? Did they culture the lungs? How did they make sure the patients were not already harboring a low grade infection prior to surgery? Did they have pre-op CT scans to rule out any bronchiectasis/mucus plugs? Bacteria can come from many sources, transported through the blood stream and show up in the lungs as well. How sterile was the intubating equipment and provider? Remember that even normal people can have silent GERD and aspirate small amounts of stomach contents. There has been noted COPD people twice the incidence than the normal population.

Yes, the type of surgery can push on the lungs and alveoli so it can take some time to re-expand all tissue. The activity of the patient, any pain medications, frequency of having patient move & deep breath are critical. Sadly, hospitals don't have enough staff or time to vigorously attend to some of the known techniques to help the lungs.

Both surgical and anesthetic techniques have evolved tremendously over the decades. More and more surgeries are being done with LMAs (laryngeal Mask Airways), anesthetic gases for doing laparoscopic surgeries that don't require muscle relaxants, and use of 'regional' anesthetics (spinal, epidural.) There remains a legitimate role for using intubation - trauma victims, compromised airway, severe respiratory distress (vs. BiPap), major abdominal/heart/lung surgeries, who are routinely given antibiotic coverage, frequently are in an ICU post-op (not out of bed or walking to help lungs clear).

Okay, I'll get off my soapbox. The best any patient can do is talk directly with the anesthesiologist or anesthesia provider about how their anesthetic will be handled in the presence of their COPD including maintenance of their usual COPD medications pre/post op. If possible, they should have pulmonary studies up to date and available for the anesthesia provider, and a GOOD patient (and family history of others that had any issues with anesthesia.) history. Also remember that online you will always read about the horror stories versus the millions of anesthetics that are done every day without any complications.

[gerald]

Excellent information Skate.  I am glad to see the someone with experience put forth other side of the argument.

This is probably an area that needs a great deal more study.

Also they need to determine if the use of the Muscle relaxants is a
necessity or if it is being done because "it has always been done".

 

[skate4life]

I did get a little more info with link to original article, a trial that was completed 3 years ago. They did check patients for up to 28 days post-op. But their summary was confusing as first statement said use of relaxants 'was associated with an increased incidence of postoperative pulmonary complications.' But at the end it stated that choice of relaxant and reversal agent nor extubation when monitor said reversal was complete was associated with better pulmonary outcomes. That seems contradictory to me....My own curiosity may spur me to see if I can find something more in recent pulmonary journals.......

As for common out-patient recommended exams/procedures, when I retired 5 years ago, we had been using only Propofol IV for sedation for colonoscopy, endoscopy, some biopsies and many where surgeon injected local anesthesia at operative site (breast, podiatry, carpal tunnel release, etc.) Been using Propofol for a number of years (had it myself) - stopped using Versed and similar drugs. Obviously country of study etc. needs to be considered as well..

Gerald - thanks for bringing attention to this topic

[joany]

  No matter though just the topic and discussion is concerning.  I'm not much of a talker socially, medically or "otherwise".  I'm an over-thinker so I can't imagine having any kind of discussion with an *ologist of any kind.  So far I've lived long because by the time I resolve what I was thinking about, the world has rotated - picture something like moving from day to night; and everything has changed, a new solution has been found.

[gnott]

Skate4Life

You certainly cleared up one thing that always seemed slightly odd: Every time one of these procedures were suggested there were four major voices -
my GP,
my Cardiologist,
my Pulmonologist, and
whatever specialist that was going to do the procedure, and
occasionally whoever was on duty in those roles at the Hospital.

(The various roles have been filled with different players over the last ten years.)

What was odd is they never once agreed! Smile!
And the disagreement was never a matter of degrees - they always ranged from "Well should be OK" to "Hell NO!". Making it odder it wasn't always the same speciality putting the NIX! on it. Making it very difficult to guess why?

For example, when I had extreme bleeding from the lungs everyone that checked in on me said "Bronchoscopy". When the doctor came in that does the bronchoscopy - he examined me, piddle with the computer, went out, came back and said "Hell NO". Ha.

Thanks to Skate4Life I now appreciate there were a ton of other factors that I never knew about. Also I can now understand why they don't talk to each other that much - if every discussion is going to come down to a "debate" - and a time-consuming review of all the data - and a professional disagreement - why go there if you don't absolutely have to.