Sunday, December 31, 2017
Monday, December 25, 2017
Strong Ion Differene - Hyperchloremic Metabolic Acidosis
SID – Hyperchloremic acidosis
Definition
Strong ions are cations and anions that exist as charged particles dissociated from their partner ions at physiologic pH. The SID (Strong Ion Difference) is the difference between the positively- and negatively-charged strong ions in plasma. This method of evaluating acid-base disorders was developed to help determine the mechanism of the disorder rather than simply categorizing them into metabolic vs. respiratory acidosis/alkalosis as with the Henderson-Hasselbalch equation.
Strong cations predominate in the plasma at physiologic pH leading to a net positive plasma charge of approximately +40: SID = [strong cations] – [strong anions] = [Na+ + K+ + Ca2+ + Mg2+] – [Cl- + lactate- + SO42-]
Disturbances that increase the SID increase the blood pH while disorders that decrease the SID lower the plasma pH. According to the law of electroneutrality the sum of positive charges is equal to the sum of negative charges. Therefore the SID must be equal to the sum of weak anions in the body (such as bicarbonate, albumin, and phosphate).
Hyperchloremic acidosis may result from chloride replacing lost bicarbonate. Such bicarbonate-wasting conditions may be seen in the kidneys (renal tubular acidosis) or the GI tract (diarrhea). This may also occur with aggressive volume resuscitation with normal saline (>30cc/kg/hr) due to excessive chloride administration impairing bicarbonate resorption in the kidneys.
The strong ion difference of normal saline is 0 (Na+ = 154mEq/L and Cl- = 154mEq/L → SID = 154 – 154 = 0). Therefore, aggressive administration of NS will decrease the plasma SID causing an acidosis. Administering a solution with a high SID such as sodium bicarbonate should be expected to treat this strong ion acidosis.
Sunday, December 17, 2017
Friday, December 8, 2017
How to do PBL right
8 Tasks for
Small Groups*
(self-directed,
interdependent, small group, problem-based learning)
- Explore the
problem (case), create hypotheses, identify learning issues.
Elaborate.
- Identify what
you know already.
- Identify what
you do not know.
- As a group,
prioritize the learning issues, set learning goals and objectives. Each member
should work on all primary learning issues.
- Individual
self-study and preparation.
- Return to the
group, share the new knowledge effectively so that all group members learn
and discuss the information.
- Apply the
knowledge to solve the problem.
- Assess the
new knowledge, the problem solution and the effectiveness of the process
used. Reflect on the process, your contribution and that of others
in the group.
·
*Adapted from, Problem-based Learning: How to Gain the Most from
PBL. Donald R. Woods. 1994, Watertown, ON, LOR 2H0, Canada.
Wednesday, December 6, 2017
Flash Cards Recommendation
FLASH CARDS
Flash
cards are a great study tool for medical students. A program called Anki, is very popular and
free. It directs your study in a
structured way over a period of time. This
is called “spaced repetition” and it promotes the good kind of memory; i.e.,
long term. The strength of Anki comes with its review feature, which shows you
cards again based on how well you knew it.
After you answer each card, you will tell Anki if you thought the card
was hard or easy, and it will show you the card again, either soon or in
several days, based on your response.
There are many ways to review your cards using Anki: you can use your
computer, phone, or do it in browser anywhere.
The review settings are very customizable, and there are even
comprehensive stats. Feel free to
explore all of these settings to find one that works best for you. If you have further questions, there are
several good help videos on YouTube. Two are listed here:
Flashcard Directions:
1.
Download the Anki client at http://ankisrs.net/
2.
Once loaded, create a user name. Creating a user name is not essential for use
of the flashcards on the computer on which you installed anki. However, if you would like to use the
flashcards online or on your cell phone, you will need to make a user account.
a.
You can use Anki for creating your own
flashcards
b.
You can use Anki to search for shared decks of
cards (there are lots of anatomy, physiology, and pharmacology decks as well as
Step 1 and Step 2 decks; e.g.
v. more
3.
In the “Review” tab, you can set options on how
missed cards are reviewed.
4.
Also, if you want everything you do on your
computer to be synced with your online, and cell phone cards, in the tool bar,
click the Settings>Deck Properties>and in the Basic tab, check the box
that says sync with AnkiWeb.
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