Showing posts with label Guest Posts. Show all posts

Guest Post: Adam's explaination of pKa that will leave you wondering why you didn't read this before that one test you had to take last year.

Adam, seen here looking both patriotic and holier-than-thou.
Leave it to an SRNA to multitask!

What the heck is pKa? Back in the Fall last year I made the mistake of explaining pKa to Amy.  Ever since then she has been asking me to write a post to help others grasp this concept.  I would love to sit here and pretend that this is an altruistic exercise, but the truth is that I continually get these questions wrong on exams and am writing this post as much for my own benefit as anyone else's.  So here it goes…

Figuring out pKa questions is easier if we remember one rule and ask two questions.  The rule to remember is: pKa DOES NOT equal pH.  We will get to the questions a little later. pH and pKa are related, but totally different….kind of like Stephan and Alec Baldwin.  Put simply pKa is a quality that drugs have.  It is the pH at which the drug is 50% ionized and 50% unionized. Ionization is important because drugs that are ionized cannot cross lipid membranes.  If they can’t cross lipid membranes they can’t get to their sites of action.  The site of action might be the brain, or a nerve axon, or whatever.  So ionization is bad.  The nonionized portion of the drug is the portion that crosses the lipid membrane and gets to the site of action.  This is the portion of the drug that “works”, therefore the nonionized part is good.

I’m gonna go way back in the memory banks here and bring back some basic chemistry.  Remember how acids and bases behave?  Acids donate H+ and bases accept them.  (H+) + (OH-) <==> HOHWhen acids and bases are mixed together they are in a constant flux of ionization (which is bad).  But, if we mix a base in a basic environment or an acid in an acidic environment ionization doesn’t happen; there is nothing there to donate an H+ to and nothing there to accept one.  The drug is less ionized (or more nonionized), which is good.

This brings us to the first question we need to ask:  Is the drug we are examining an acid or a base?  Examples of basic drugs are local anesthetics and opioids; some of our acidic drugs are the barbiturates. 

So let’s pretend we are dealing with the basic drug lidocaine, whose pKa is 7.74.  So at a pH of 7.74 there is exactly 50% ionized lidocaine and 50% unionized.  Is this drug an acid or a base?  A base, like we just talked about. 

This brings us to our second question:  Are we placing our drug into a relatively more acidic or basic environment compared to the drugs pKa?  What is normal body pH?  Anyone, anyone…Bueller…7.4.   So, if we put this basic drug which is 50/50 at a pH of 7.74 into a relatively more acidic environment (body pH is 7.4, therefore relatively more acidic than 7.74) will we get more ionized or unionized drug?  I really hope you all said more ionized. 

Let’s deal with an acidic drug, like the barbiturates. The pKa of methohexital is 7.92.    So, we know this is an acidic drug that is 50/50 at a pH of 7.92.  Now we inject that into the body with a relatively more acidic pH of 7.4, will there be more ionized or nonionized drug?  Please say more nonionized. 

Did anyone notice that this acidic drug had a pKa greater than 7.0?  This is an excellent example of our #1 rule: pKa DOES NOT equal pH.

On exams I always find it super helpful to draw it out.  Here are some extreme examples (Click on each to enlarge):



Guest Post: Rachel on the life of an SRNA spouse

Have you ever wondered what a Miller blade is? How about defining the word intubation? Or better yet, how often do you use the word “gas” in everyday conversation? Well get ready peeps the fun is about to begin!

I’m married to a former engineer, turned nurse, turned SRNA working toward becoming a CRNA. We’ve been on quite a path together over the last 12ish years that includes many college degrees between us both, full time jobs, being full time students (again, and again, and again . . .) school loan debt, marriage, putting off starting a family because we’re obviously addicted to higher education, a sweet dog, and owning and selling 2 houses only to return to rental properties, and moving several times. Through all of that, my husband’s ultimate goal has always been to have a career as a nurse anesthesia provider. He certainly did not take the most direct path, but sometimes you don’t know what you want until you try what you thought you wanted.
So what’s it like to be married to an SRNA? It’s hectic and stressful at times. They are stressed and sleep deprived. They don’t have much time for life outside of school or clinical. And ultimately the student and the spouse are constantly trying to juggle all the demands of school, life, and a relationship. But, that said it is not impossible (note: I did not say it was easy!).
The first 8 weeks of anesthesia school seem to be the worst for everyone involved. SRNAs are balls to the wall (yep, that’s the only way to describe it) busy with class at least 35 hours per week, studying after class until their eyes literally fall shut, and then on weekends not seeing the light of day for sometimes 36 hours because they are studying constantly. And then . . . come Monday, repeat. For 8 weeks! I was not privy to this “special” time in the life of my SRNA because I was in Portland OR pursuing my own academic endeavors as an aspiring physical therapist. But, even maintaining some form of marriage via phone was a challenge.
Now that those 8 weeks of hell have come and gone, everything else seems much easier. My SRNA is still busy all the time. He still gets stressed and doesn’t have much time to interact before tests or when he is up late at night finishing his careplan for clinical. He doesn’t have much time for chores like cooking, laundry, cleaning or taking care of errands. Heck, he struggles to find time to shower and sleep. But, ultimately we eat dinner together most nights of the week, and at least spend the evening next to each other on our computers. Now that’s love huh?
Since I am in school too I think our perspective may differ from many. On the down side, we’re broke, both stressed, weekends are never school work free and we both have priorities competing with our home life. But, on the positive, my SRNA never has to explain to me why he can’t go enjoy a Sunday afternoon strolling around Salem Lake or why he can’t go away for the weekend. I get it-even if I don’t always like it.
Embarking on the journey as a spouse to an SRNA is a wild ride with high and lows. But like any decent adventure the growth takes place during the process and the reward at the end is always worth it. Your partner will have a satisfying, fulfilling career which will afford your family flexibility in their work schedule and a salary that rewards their hard efforts. I’m the daughter of a CRNA and a wife of an SRNA. And better yet, my mom and I are both still standing.

This blog, it is a-changin'!

After much pestering, Rachel, the lovely wife of my classmate, Dave, has agreed to write the first TAR guest post!  This is incredibly exciting for a number of reasons:

1. As I stated at the outset, I'm just one person.  With that comes one person's experiences and viewpoint and that makes for a pretty narrow range of covered topics.  That's great if your my stalker, but not so wonderful for anyone else who reads this little blog in the hopes of actually gleaning useful information from its pages.  There are a number of major issues that factor into choosing Nurse Anesthesia as a career path and succeeding as an SRNA - kids and spouses, for example - that I simply cannot speak to, but which are of great interest to many.  So I'm hunting down people that can expand on these topics and coercing them into doing just that.*

2.  I get to click the "Post This" button, without having written a lick of text myself, and POOF!!  A post appears.  It's like magic!

3.  Rachel is amazing.  She's the kind of girl you meet and think to yourself, "please, Lord, look out for any other women who marry into Dave's family because there is no way they will be anything less than second-rate daughters-in-law compared to this gem of a human being."  (No really, that thought literally entered my head upon first meeting her.  You can ask Dave.)  I can only hope that a tiny smidge of Rachel's awesomeness will rub off on the blog.  If so, legions of people will flock to this site and I'll be famous.  Move over, Perez!

The lovely Rachel and her SRNA beau

So check back every so often, as Rachel's entry related to life as the spouse of an SRNA should make its way online over the weekend or early next week!


* I cannot comment on my blackmai- I mean, coercion tactics at this time.