Perfusion - Study guide 3 Flashcards
Four determinants of cardiac output
- Heart rate
- Preload
- Afterload
- Contractability
The number of cardiac contractions per minute. Can be affected by many variables depending on pressure.
Heart rate
increases HR by releasing norepinephrine
Positive chronotropic effect
decreases HR by releasing acetylcholine
Negative chronotropic effect
- Directly related to stroke volume.
- The amount of blood in the ventricles at the end of diastole.
- Also refers to the amount of stretch of the muscle tissue at the end of filling.
Preload
- Inversely correlated to stroke volume.
- The resistance to flow the ventricle must overcome to open the semilunar valves and eject its contents.
- This is related to bp, vessel lumen diameter and or vessel compliance.
Afterload
- The force of the mechanical contraction.
- Contractile force can be increased with sympathetic stimulation or calcium release.
- It can be decreased in the face of hypoxia or acidosis
Contractability
Effects of an increased afterload
Decreases stroke volume and decreased cardiac output
Effects of a decreased afterload
increases stroke volume, increases cardiac output
Formula for calculating cardiac output
Heart Rate X Stroke Volume = Cardiac Output
Normal cardiac output in a healthy adult
4-7L/min
HR increases depending on what?
Pressure
Conditions that cause alterations in perfusion
7 - CCCDEHM
- Clotting disorders
- Congenital cardiac defects
- CAD
- Dysrhythmias
- Early menopause
- Heart Failure
- MI
Parameters that for someone to be dx with pre-eclampsia
- BP >140>90 on two occasions at least 4 hrs apart with Proteinuria.
- Occurs after 20 wks.
- Protein creatinine ration (PCR) >0.3 MG/DL
Nursing Interventions for Pre-eclampsia
12
- Monitor BP
- Monitor weight
- Frequent provider visits
- Fetal kick counts
- Frequent rest/bedrest
- Adequate intake
- Monitor I and O
- Neuro status checks
- Evaluate renal function
- Evaluate Deep tendon reflexes and clonus
- Administer magnesium sulfate infusion as ordered
- Administer HTN medications
test where you have the patient dangle legs off side of bed w/o feet touching the floor, support the back of the leg with one hand and push up on the toes (dorsiflex foot).
Clonus test:
Normal response for a Clonus test
Foot returns to normal positon with no tremors
can be reffered to as a negative clonus
Indications of a Positive clonus test
Foot starts to bounce or beat 3 or more times
Theraputic range for mg
4-7 mEq/L
Normal range for mg
1.5-2 mEq/L
S/S of mg toxicity
think BURP
BP Decrease
Urine output decrease
Respiratory rate decrease
Patellar reflex absent
Antidote for mg toxicity
Calcium gluconate
Life-threatening and rare compication of pre-eclampsia.
Can manifest at anytime during pregnancy
HELLP Syndrome
A pt with preeclampsia is experiencing the following that do you suspect
N/V
Epigastric pain
Headache
Vision problems
Hepatic dysfunction
liver failure
Acute renal failure
DIC
Respiratory Failure
Multi-organ system failure
HELLP Syndrome
What does HELLP Syndrome stand for?
H-Hemolysis
E-Elevated
L-Liver Enzynes
L-Low
P-Platelets
How to treat HELLP Syndrome
9
- Priority is to deliver the baby
- Fresh frozen plasma
- Antihypertensive
- Magnesium Sulfate Infusion
- Keep calcium gluconate immediately available
- Continuous monitoring of mother-fetus
- Strict Bedrest
- Hourly urine output measurement
- Strict I and O
Assessment tool for pre-eclampsia
Think SPASMS
S – Significant blood pressure changes may occur without warning
P – Proteinuria is a serious sign of renal involvement
A – Arterioles are affected by vasospasms that result in endothelial damage and leakage of fluid into the interstitial spaces. Edema occurs.
S – Significant lab changes (Elevated LFTS and decreased platelet count) signal worsening of condition.
M – Multiple organ systems involved (CV, Hematological, Hepatic, Renal, and CNS)
S – Symptoms appear after 20 weeks gestation
parameters for diagnosing someone with pre-eclampsia with severe features
BP > 160/ > 110 …..while on bedrest, on two occasions at least 4 hours apart
If pre-eclampsia continues to deteriorate what should you prepare for?
- Prepare for induction of labor
- Prepare for C-section delivery as indicated
- Prepare for delivery of pre-term infant
- Resuscitation supplies at bedside
- Additional staff designated to care for pre-term infant
- Provide teaching and support to the client and family
HTN medications that are safe for pregnant patients
- Labetalol
- Nifedipine
- Hydralazine
- Sodium Nitroprusside
- HCTZ
A positive clonus and hyper-reactive DTR indicates what?
CNS Irritibility and increased risk for seaizures
