Exam (elaborations)
NR 340-Exam 2 Study Guide-Critical Care graded A
- Course
- Institution
NR 340-Exam 2 Study Guide-Critical Care graded A
[Show more]
Seller
Follow
maggieobita
Reviews received
Content preview
NR 340-Exam 2 Study Guide-Critical Care graded A7
Blood Flow Review
Basic Electrophysiology
• Automaticity-The ability for the heart muscle to generate it's own electrical activity
o Pacemaker Cells arise naturally from the SA Node
o Electrolytes involved are K+, Na+, & Ca+
Cardiac Action Potentials
• Depolarization-occurs when charge is more (+)
o P wave=atrial depolarization
o QRS complex=ventricular depolarization
o contraction
o Systole
• Repolarization-recharging period when charge is more (-)
o T wave=ventricular repolarization
o filling
o Diastole
• Electrical + Mechanical=Cardiac Contraction
,NR 340-Exam 2 Study Guide-Critical Care graded A
• Action Potential Curve
o See Below-Sodium, Potassium, & Calcium flow in & out of the cell at different times
allowing for charge changes and contraction of heart muscle tissue.
o 4 Phases
▪ Early Repolarization
• sodium channels close
▪ Phase 2-Plateau Phase
• potassium leaves cell
▪ Phase 3-Rapid Repolarization
• calcium channels close
• potassium returns into cell quickly
▪ Phase 4-Resting Phase (polarized state)
• active transport through the Na-K pump begins restoring K to inside the cell &
sodium to the outside of the cell
• cell membranes become impermeable to sodium
• Potassium may move in & out of the cell
Intrinsic Rates of Conduction Pathway
• SA Node
,NR 340-Exam 2 Study Guide-Critical Care graded A
o natural pacemaker
o 60-100 bpm
• AV Node
, NR 340-Exam 2 Study Guide-Critical Care graded A
o takes over as pacemaker if SA node can't do the job
o 40-60 bpm
• Purkinje Fibers
o last resort to pace heart if both SA & AV nodes fail
o 20-40 bpm
Cardiac Monitoring
• 12 lead ECG
o only 10 electrodes used to monitor, but gives 12 overall electrical pictures
▪ 4 limb leads
▪ 6 trunk leads
o shows change or damage to heart muscle
▪ ischemia, infarct, enlarged cardiac chambers, electrolyte imbalances or drug toxicity
Calculating Heart Rate from a 6 Second Strip
• Graph Paper
o Vertical boxes measure voltage or amplitude
o Horizontal boxes measure time (in seconds)
▪ 1 small box=0.04 seconds
▪ 1 large box=0.20 seconds
▪ 5 large boxes=1 second
• a six-second strip will be 30 large boxes
• To calculate rate on a 6 second strip, count R-to-R and multiply by 10
Cardiac Waveforms & Determining Rhythm
• P Wave
• atrial depolarization
• 0.04-0.10 seconds in duration
▪ Are they present?
▪ are they regularly occurring?
▪ is there a P for each QRS?
▪ are the P waves smooth, rounded, & upright?
▪ do all P waves look similar?
• QRS Complex
• ventricular depolarization
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller maggieobita. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $22.49. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
77764 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now