OB Flashcards
Most physiologic changes occur in the ___ trimester, and most anatomic changes occur in ____
Physiologic = 1st trimester
Anatomic = 2nd and 3rd trimesters
Are the physiologic and anatomic changes in pregnancy good or bad?
Mostly good.
Respiratory changes in pregnancy
1) Increase in ventilation - D/t increased metabolic demand - Increase 40% TV and 15% RR - Increase 50% MV overall - High ventilation will decrease CO2 levels (goes into resp alkalosis pH = 7.44) 2) Decrease in airway resistance - d/t increased progesterone - Lung compliance unchanged 3) Increase in O2 Consumption - Increase by 20% - Curve shifts to the right (P50 increases from 26-28mmHg)
Anatomic respiratory changes in pregnancy
1) Cephalad diaphragm displacement 2) Weight gain and breast enlargement (pressure on the chest and boobs might get in the way of airway) 3) Vascular engorgement of the respiratory tract mucosa - Mucus membranes fragile 4) Edema of nasopharynx, oropharynx, and the cords
When is edema of the nasopharynx, oropharynx, and the cords most common?
During pre-eclampsia Remember there is HTN and loss of plasma proteins.
Effect of pregnancy on the FRC
Decrease by 20% Less safe apnea time!!
Why can pregnant ladies desat quickly?
Low FRC and high O2 consumption rate (20% higher than normal).
We can expect induction during pregnancy to be (faster/slower) than the non-pregnant patient. MAC should be (increased/decreased) by ____.
Faster induction Decreased MAC by 25-40%
Effects of maternal hyperventilation
Alkalosis - Shift to the left (will decreased O2 release to the fetus) - Constriction of the umbilical and uterine blood vessels This is only a problem with prolonged hyperventilation
Effects of elevating the diaphragm
Decreased FRC and displacement of the heart (look at EKG, listen for murmur, possible dysrhythmia)
Pregnancy and coagulation
Overall, it is a hypercoagulable state Increased clotting factors (fibrinogen and factors 5-8) Platelets remain unchanged or may decrease slightly
CO will be (increased/decreased) during pregnancy
Increased
What happens to BP and SVR in pregnancy
SVR will decreased by 20% - vessels lose their SNS tone BP will decrease slightly - ADH is cleared more rapidly - BP maintenance depends on RAAS b/c vessels have lost their SNS tone
Your pregnant patient is lying supine and starts to drop their BP. What is this and how is it treated?
Supine Hypotensive Syndrome - It’s possible compression of vena cava or aorta. Treatment: - Left or right uterine displacement (depending on which vessel is compressed) - Hydrate before induction - Treat hypotension with ephedrine or phenylephrine
Supine hypotension syndrome is a risk > ____ weeks and can decrease CO by up to ___%
20 weeks 30%
Plasma volume increases by ___% but RBC volume only increases by ___%.
Plasma 50% RBC 20% Causes a dilutional anemia
Normal blood loss during vaginal birth
500cc
Normal blood loss during a c-section
500-1,000cc
GI changes in pregnancy
As a result of physiologic and hormonal changes: - Delayed gastric emptying - Everything in the GI tract slowed overall - Secretions are more acidic - Stomach is displaced upward and at 45 degree angle to the right. This displaces the intra-abdominal portion of the esophagus into the thorax, decreasing tone to the lower esophageal sphincter, causing reflux
All parturients greater than ___ weeks are considered full stomachs
12 weeks Aspiration risk continues into the post-partum period, until the body has time to normalize hormonally, physiologically, and anatomically.
Aspiration prophylaxis in pregnancy
Give non-particulate antacids, H2 blockers, and/or reglan. Consider doing regional instead. If doing GA, do RSI.
Renal Changes in Pregnancy
High CO and large blood volume cause an increase in GFR by 60%. Creatinine clearance increases, decreaseing serum CR
Increased glucose excretion
increased bicarb excretion (compensation for respiratory alkalosis)
Hepatic Changes in Pregnancy
Slight increases in AST and ALT Bigger changes will be seen in HELLP syndrome (part of pre-eclampsia)
Biliary stasis and increased secretion of bile leads to increased gallbladder disease