Lidocaine Before Induction

So before a case today my preceptor asked why we give lidocaine before induction.  I told him it was for patient comfort to blunt the burning senstation caused by propofol.  He told me, "that is absolutely the worst answer I could have picked."  He was beside himself and so was I.  I must have been told this before but have lost it somewhere in the recesses of my mind. I was a little annoyed how he responded but no matter, I was there to learn.  So the "real" answer is, lidocaine is used to blunt the stimulus caused by laryngoscopy.  I guess I always thought fentanyl and paralytics took care of that.  He said reducing the burning sensation from propofol is a "side effect" of using lidocaine, not its intended purpose. The standard dose here is 60 mg of lidocaine IV.

As a side note, apparently UMKC students are notorious (according to one person) for drawing air out of an IV line and then throwing the syringe away with saline still in it.  The preferred method is just pushing the saline back into the IV line.  I know most of us already do that but in case you don't, now you know.

Rapid Shallow Breathing Index

An anesthesiologist recently explained to me the RSBI or Rapid Shallow Breathing Index.  This index is used to predict whether a patient is ready to be extubated.  It is most commonly used in the ICU, but can be used in the operating room as well.  The rapid shallow breathing index is the ratio of respiratory frequency to tidal volumes in liters.

RSBI = (f/VT)

For example, if a patient is breathing 25 breaths/min with a tidal volume of 100mL, there RSBI = (25)/(0.1) = 250 breaths/min/L

So what does this number mean?

An RSBI >100 means they are NOT ready for extubation
An RSBI <100 means they are ready for extubation

No one cares how much you know until they know how much you care

A few years ago I went in for an appendectomy. I was laying on the OR table and I'll admit I thought to myself that there was a chance I wouldn't wake up. I knew it was a small chance but just the thought made me a little anxious. Just before induction the anesthesiologist grasped my hand and held onto it until I drifted off to sleep. I remember being comforted just knowing someone cared. A couple weeks ago I got to be on the giving end instead of the receiving end and I was reminded of the need for compassion toward our patients, especially the kind of compassion that they can feel. Prior to a patient getting an IV and arterial line she told me she was nervous and didn't like being stuck with needles.  I told her I didn't like needles either and in fact most people don't like needles. While the anesthesiologist was trying to get the arterial line in on her left wrist I took her right hand and held it. I just thought she would probably want something to squeeze, at least I know I would if I were in the same situation.  The attending had a difficult time getting the line in the wrist.  After making several attempts with the ultrasound he decided to try the brachial.  As they were prepping for the brachial she looked at me and said "this looks serious."  She was right, it did look a lot more serious than a simple radial arterial line. I explained that they were doing the same thing that they tried to do in her wrist but that they have to do a sterile prep when they are trying to access the brachial artery. That seemed to calm her down some. She squeezed my hand several times throughout the procedure. Unfortunately the attending anesthesiologist was unsuccessful in his attempts so we would have to do the line in the OR after induction. After the procedure was over I hadn't really given much thought to my efforts to comfort this patient until she had a complication with her surgery and had to return for a second surgery a few days later (this is the patient I wrote about who had the chyle leak). I didn't get a chance to see her in preop the second time but I helped with the anesthesia in the OR. After we transferred her to the OR table I grabbed her hand to help her move toward the head of the OR table (at this point she's had 2 mg of versed and 100 mcg of fentanyl). 

As soon as I grabbed her hand she looked up at me and said "Travis, right?"  I was shocked. I said, "Wow! You remember my name! I'm so impressed."  She began explaining how nice I was to her while she was being "tortured." I didn't realize that I would have that kind of impact on a patient simply by showing compassion. I remember interviewing at a couple DO schools and they put a lot of emphasis on the power of touch.  It should be a greater part of our practice. It does make a difference. I'm not saying we need to hold every patient's hand but we should be sensitive to the needs of our patients and if they need comfort we should act with confidence. I am reminded of a famous quote by Theodore Roosevelt: "No one cares how much you know until they know how much you care."

The Tube is in But no Capnography

We had a case the other day for a patient that had just had a lung lobectomy of the right upper lobe three days prior. She was subsequently diagnosed with a chyle leak when they observed a milky fluid in her chest tube drain (See image on left).  Chyle is a fluid consisting of a mixture of lymphatic fluid (lymph) and chylomicrons that has a milky appearance. Chyle leaks are uncommon but can be an adverse result of trauma to the thoracic duct (lymphatic vessel) during thoracic surgery.  Interestingly, in order to help the surgeon identify the leak they feed the patient ice cream the night before the surgery and intraoperatively, anesthesia inserts an OG tube and delivers a half-pint of heavy whipping cream.  I never thought heavy whipping cream would ever be part of our arsenal. 

Coincidentally, I was involved in the anesthesia for both surgeries. This patient was a 365-pound female but surprisingly she was not a difficult intubation the first time.  The second time was a different story. We all assumed this would be a straight-forward intubation just as before, regardless we still had the videoscope in the room and ready to go if needed. The anesthesia personnel consisted of the resident, two anesthesiologists, and myself. After induction the resident did the laryngoscopy with a MAC 3 blade, had a grade I view, and advanced the endotracheal tube (ETT) past the vocal cords.  She did not get condensation return in the tube and capnography was negative. She listened for breath sounds and said she could hear breath sounds but the anesthesiologist said "you're not it" and pulled the tube. The anesthesiologist handed the tube and blade with the videoscope to the other anesthesiologist while we re-oxygenated the patient. The same thing happened. The other anesthesiologist took over and made the third attempt and got the same result. She asked for the bougie, passed the bougie through the vocal cords, removed the videoscope, advanced the ETT over the bougie and past the vocal cords, removed the bougie and got the same result, no condensation and no end-tidal CO2. In all of the cases we were able to move air in but with some resistance. The next attempt the anesthesiologist used a new ETT and left the videoscope in place while removing the bougie to make sure that the bougie wasn't taking the ETT out while it was being withdrawn.  After confirming that the ETT was in place the thoracic surgeon advanced the bronchoscope down the ETT and saw a significant amount of mucous. He suctioned several globs that were quite thick and near the carina.  After suctioning out the mucous we were finally able to get end-tidal CO2 on the monitor. The conclusion by the anesthesiologist and the surgeon was that the mucous was making a ball-valve at the tip of the ETT every time it was advanced. In other words, air could be pushed past the mucous in one direction but whenever air tried to go back through the tube the mucous would close off the tip. Thinking about this more this patient could easily have received significant barotrauma if the anesthesia team continued to force air in without getting air out in return.

Intubating a Myasthenia Gravis Patient

We had a patient with myasthenia gravis who came for transthroacic removal of his thymus.  Because the disease is an autoimmune disorder the thymus can be removed to help control symptoms relating to MG. In MG, antibodies bind to acetylcholine receptors decreasing the number of functional acetylcholine receptors that results in an increased sensitivity to nondepolarizing muscle relaxants (NDMRs) and a resistance to succinylcholine. Often times we don't paralyze these patients because they already have muscle weakness and combined with volatile agent are adequately relaxed for laryngoscopy.   I presume this was the assumption my attending was working under when he decided to allow my preceptor to intubate without providing muscle relaxant.  We were also placing a double-lumen tube (DLT) which made the situation even more risky. While advancing the DLT past the vocal cords the patient began to bite down on the laryngoscope. The attending told her to leave it in but she felt it was best to try to pull it out, which she did. Unfortunately the patient lost about 1mm of tooth from the top of his lower incisor.  Looking back on the mishap I wonder what things we could have done differently.  Would putting in a bite block before laryngoscopy be wise or would it just get in the way? Would using an LTA kit have helped dampen those reflexes since the patient didn't start biting until she past the DLT past the vocal cords? Did we find out enough about the patients severity of the disease before the procedure? Could we have given sux or a NDMR?  Baby Miller suggests that we can.

Measurement of neuromuscular function in patients with myasthenia gravis treated with pyridostigmine demonstrates resistance to the effects of succinylcholine. The ED95 is approximately 2.6 times normal. Because the dose of succinylcholine commonly administered to normal patients (1.0–1.5 mg/kg) represents three to five times the ED95, it is likely that adequate intubating conditions can be achieved in patients with myasthenia gravis using these doses. The mechanism for the resistance to succinylcholine is unknown, but the decreased number of acetylcholine receptors at the postsynaptic neuromuscular junction may play a role.

What do you think is the best approach? Is there anything you would have done differently? Comment below.

Resources

Hey guys! Dr. Harder at the Leavenworth VA gave me 10 GB of books and resources for me to distribute to the students in the program. I am trying to upload them on google docs and maybe drop box so they will be easier to access. I have uploaded a few to google docs and have sent the links to Melanie to forward to all of the students in the program. If you any of you guys are in the KC area right now and would like to meet up so I can just transfer the files to your computer or want me to send you the links, please text me! Thanks.

Communication Crisis

Stephen R Covey's book "Seven Habits of Highly Effective People"  states that Habit number 5 is "Seek First to Understand, Then to be Understood."  This is the lesson I learned Friday when the patient who the resident had just put a central line in went bradycardic and hypotensive.  I don't recall perfectly the sequence of events but I was asked by the attending physician to administer 1 mg of phenylephrine.  Yes you read that right, 1000 mcg of phenylephrine.  I questioned it too.  I turned to the resident and asked if that was what she heard and she said "yes, 10 CCs"  So, with some reservations, I gave the whole stick of phenylephrine.  I watched the blood pressure climb but nothing too significant.  A short while later the heart rate dropped and the attending gave atropine. Although the heart rate started looking better the blood pressure was low again so I was asked for a second time by the attending to give another 1 mg of phenylephrine. Being new to this situation I assumed she knew what she was saying since this was the second time she had said the same thing.  I proceeded to push 10 CCs of phenylephrine but before I got halfway she yelled at me, "Stop! What are you doing! I said two CCs!"  To which I responded, "But you told me to give 1 mg!" She came to where I was standing took the syringe from my hand and withdrew as much phenylephrine as she could.  The patient probably got 400 to 500 mcg phenylephrine maybe even a little less.  I went and stood out of the way while I watched the blood pressure climb to somewhere around 250 systolic.  The patient supposedly went into PEA for a few seconds after which the attending gave a few ineffective one-handed chest compressions.  The patient's vitals soon normalized and all was well.  Meanwhile I got an earful from the attending.  Paraphrasing her words she said, "We never give 1 mg of phenylephrine! Why would you give that much?!  We never give that much at once!  I shouldn't have asked you to even do it!  Even if I told you to give 1 mg you should never give 1 mg!"  I apologized to her and told her I should have communicated better. I couldn't get it out of my mind the entire weekend.  I kept shaking my head in disbelief whenever I thought about it.  However, I am thankful for the experience because I know I will never give a drug that I am told to give without verbalizing it.  Hopefully you won't either.