Quiz #2 Flashcards
Human Chorionic gonadotropin
- Produced by developing conceptus and placenta
- Basis of many pregnancy tests and lab tests
- Prevents involution of corpus luteum
- Causes corpus luteum to secrete larger quantities of
sex hormones
Understand the formation, function, and flow of blood through the placenta
Formation: formed from trophoblastic cells around the blastocyst
Blood-flow: diffusion
Function:
Describe the response of the body to pregnancy
Weight gain: Average 24 pounds total
- Fetus: 7 pounds
- Placenta, amniotic fluid: 4 lbs
- Uterus: 2lbs
- Breasts: 2 lbs
- Plasma volume: 6lbs
- Fat: 3lbs
Circulatory:
*Although overall amount of red blood cells increases, hematocrit decreases because plasma volume increases by so much more
Metabolism & Nutrition:
- Basic metabolic rate increases about 15% during
latter half of pregnancy
- Placenta stores of nutrients are needed to sustain
fetal grown during the last months of pregnancy
Respiratory: Increased RR
- 20% increase in oxygen used by mother at term
- Progesterone increases minute ventilation
- Uterus presses abdominal content up against the
diaphragm
Kidney function:
- Glomerular filtration rate increases a lot, more to
filter out because of the fetus
- Systemic vascular resistance decreases a lot
Breast development:
- Milk ducts develop
- Soreness often early sign of pregnancy
Describe anatomical changes that contribute to common complaints during pregnancy
Breast enlargement: sore breasts, sometimes leakage
Lungs: pressure on diaphragm makes breathing harder
Bladder: pressure on bladder increases frequency and urgency of urination
Small intestine: pressure results in constipation
Lower back: Extra curvature and soreness
Stomach: pressure on stomach makes eating large amounts difficult, mostly see eating small frequent meals – N/V
Describe US regulation that addresses safety of drugs in pregnancy.
Males/females reproductive potential
New labeling:
- Pregnancy (includes labor and delivery)
- Lactation (includes nursing mothers)
Females and males of reproductive potential
Define FDA pregnancy categories
A: Controlled human studies fail to demonstrate risk in 1st trimester; no evidence of risk in later trimesters
B: Animal – failure to demonstrate risk (or do show risk, but controlled human studies do not) Human – no controlled studies
C: Animal – adverse effect on fetus or no studies done; Human – no controlled studies
D: Human – proof of human fetal damage; “WARNING” statement on drug label
X: Animal or human studies demonstrate definite risk of fetal abnormality; “CONTRAINDICATION” statement on drug label
Identify nursing actions to support safe use of drugs in pregnancy.
- Educate women of child-bearing age
- Assume any drug will reach the embryo/fetus
- Weigh risk vs. benefit
- Is a drug needed?
o Eliminate unnecessary drugs
o Avoid certain drugs; if drug therapy is necessary
o If necessary, use drugs with better safety profile - Avoid substances of abuse (before & during)
- For known teratogens (e.g. isotretinoin, Retin-A)
o Written informed consent
o Multiple forms of contraception
o Pregnancy test just prior to initiation, etc.
Estrogen
- Produced by corpus luteum and placenta
- Enlargement of uterus, breasts, and external
genitalia - Relax pelvic ligaments
Progesterone
- Role in nutrition of early embryo
- Decreases uterine contractility
- Helps estrogen prepare breasts for lactation
- Increases minute ventilation
PK changes in childhood
Distribution:
- Limited protein binding
- BBB not fully developed
Metabolism
- Capacity of newborns is low; approaches adult level by a few months of age and complete liver maturation occurs by year 1
- Children over 1 year metabolize faster than adults; peaks around 2 years of age
Renal excretion
- Significantly reduced at birth
- Adult level of renal function achieved by 1 year
IM Absorption: slow and erratic in neonates but becomes more rapid in early infancy vs neonates and adults
Transdermal absorption more rapid and complete in infants vs older children and adults
Arterial values of pH, pCO2, HCO3, pO2
pH: 7.35-7.45
pCO2: 35-45 mmHg
HCO3: 22-26mmHg
pO2: 80-100
3 chemical buffers
- Bicarbonate-Carbonic acid buffer (ECF)
CO2 + H2O –> H2CO3 –> H+ + HCO3 - Protein buffer (ICF) - hemoglobin
- Phosphate buffer (ICF) - Sodium phosphate
2nd line buffers and their speed
Respiratory system (Hours)
Renal system (Days)
Respiratory buffer system
- If basic: breathe slower and shallower to increase CO2 gas to the blood, increase H+ and decrease pH (makes acidic)
- If acidic: breathe faster and deeper to remove CO2 gas from the blood, lower H+, and increase pH (makes basic)
Renal system buffer
Kidneys can do 2 things:
- Secrete more or less H+ into renal tubule (phosphate and ammonia assist the kidneys)
- Secrete more H+ = increase pH
- Secrete less H+ = decrease pH - Reabsorb more or less bicarbonate into the blood (kidney can decide)
- more base in the bloodstream increases pH
- less base back in the bloodstream decreases pH
Na role and range
- Major ECF fluid cation
- Primary puller of water (regulates osmotic forces and water balance)
- Regulates acid-base balance
- Facilitates nerve conduction and neuro-muscular function
- Transport of substances across cellular membrane
135 - 145 mEq/L
K role and range
- Major ICF fluid cation
- Maintains cell electrical neutrality
- Facilitates cardiac muscle contraction and electrical conductivity
- Facilitates neuromuscular transmission of nerve impulses
- Maintains acid-base balance
3. 5 - 5 mEq/L
Ca role and range
- Vital for cell permeability
- Bone and teeth formation
- Blood coagulation
- Nerve impulse transmission
- Normal muscle contraction
- Plays important role in cardiac action potential
- Essential for cardiac pacemaker automaticity
9-11 mg/dL (or 4.5-5.5 mEq/L)
Mg role and range
- Women’s health and pregnancy
- Smooth muscle contraction and relaxation
- Suppresses release of acetylcholine at neuromuscular junctions (Low mg; higher Acetylcholine; more muscle spasms)
(High mg; low acetylcholine; decreased movement including respirations)
1.5 - 2.5 mEq/L
pH normal range
7.35 - 7.45
Distribution of Fluid throughout the body
1/3 TBW in ECF (interstitial and plasma)
- Includes interstitial fluid and plasma
- Interstitial fluid is between the cell membrane and the capillary membrane
- movement between interstitial and plasma is by filtration and absorption (managed by hydrostatic and colloid forces)
2/3 TBW in ICF
- Movement between ICF and ECF is through osmosis
Total Body Water as % in infants, adults, and older adults
Infant: 70-80%
Adult: 50-60%
Older adult: 55%
Major solutes inside and outside cell
Inside: K+ and Protein
Outside: Na+ and Cl-
Osmotic pressure
force that attempts to balance the concentration of solute and water between intracellular and extracellular fluids (by moving water)
- Water flows toward the higher concentration of solutes