OB Flashcards
For OB patients, you want to make sure to have this type of cart
Difficult Airway
When is there the greatest cardiac demand on parturients?
During and right after delivery.
When are parturients at greatest risk for myocardial ischemia?
During and right after delivery, because this is the period of greatest cardiac demand
A parturient is considered a full stomach after ____ weeks
12
Why are pregnant women at risk for gallstones?
Everything in the GI tract slows down, causing stasis.
A fetus is considered acidotic if pH is
7.2
Fetal bradycardia is considered
Normal amount of variability for a fetal HR
5-25bpm
Normal fetal HR
110-160
This can cause fetal bradycardia
Maternal hypotension, maternal hypoxemia, uterine contractions/hyperstimulation, vagal head compression, umbilical cord compression.
Treat with fluids, positioning, and oxygen, stop oxytocin.
CO returns to normal ___ weeks post-partum
4 weeks
HR will increase by ____, CO increases by ____, and SV increases by _____
HR 23-30%
CO by 30-50%
SV by 20-50%
BP changes
SVR decreases by 20%, but SBP is unchanged. This is probably due to the increase in CO. MAP however, decreases slightly.
What can cause hypotension in parturients?
Supine positioning
Induction agents
Sympathetic blockade from regional blocks
Treatment of maternal hypotension
Positioning, fluids, O2, TED stockings, Ephedrine & Phenylephrine
Compression of IVC vs. aorta
IVC compression causes a decrease in venous return, CO, and thus causes hypotension.
Aortic compression is usually not associated with s/s, but does decrease uteroplacental perfusion
Plasma volume increases by __%, but RBC volume only increases by ___
50%
30%
Coagulation in parturients
Clotting factors increase (in preparation of delivery). Plts remain the same or decrease slightly.
Plasma cholinesterases in parturients (increase/decrease)
decrease.
Will have prolonged duration of sux!
EBL for vaginal delivery
500cc
EBL for c-section
800 - 1000 cc
1500 cc for hysterectomy
Regional anesthesia is not advised if plt counts are below
70,000
When should you suspect a PE?
parturients are at risk for PE because their coagulation factors have increased. PE should be suspected if mother has SOB, chest pain, coughing up blood, arrhythmias, pain or tenderness in legs.
We want mothers to ambulate early and wear compression stocking!!
Respiratory changes in parturients
Decrease in FRC (20%)
Small airways close faster
Increased WOB
O2 demand increases by 30% (increase in TV by 50%, RR also increases)
The dissociation curve will shift to the
right
Effects of progesterone on respirations
Tells resp center to increase respirations
Sensitizes the resp center to CO2 (increases MV to drive maternal PaCO2 to 30-32, causing a compensated respiratory alkalosis with excretion of bicarb)
Chest muscle relaxation, allowing the chest wall to expand more easily
ABG of pregnant women
Remember that they have increased sensitivity to CO2 d/t progesterone, so they have an increased MV. This results in a compensated respiratory alkalosis, normal pH, low pCO2, and low bicarb
Why is it important for parturients to have oxygen?
Increased oxygen consumption, decreased FRC, and decreased CO when supine
Why is hypoventilation in parturients so bad?
It decreases O2 availability to fetus, also, mothers can quickly develop acidosis, causing BVs to constrict, decreasing flow uteroplacental flow
Will IAs have a faster or slower effect on parturients?
Faster
d/t increase in MV
Choice of ETT size in parturients
6.0-7.0
Generall err on the smaller side, because they may have edematous airways
Clinical implication of full stomach past 12 weeks rule
Bicitra given to all laboring women
Reglan
H2 Antagonists (Ranitidine, Famotidine)
GI changes
Stomach displaced upward & 45° to the right & displaces the intra-abdominal segment of the esophagus into the thorax → ↓ tone of the lower esophagus → ↑ incidence of reflux
Mechanical obstruction to outflow through pylorus → ↑ gastric volume
↑ gastric acidity (placental derived gastrin mediated)
Esophageal peristalsis & intestinal transit slowed → ↑ gastric volume
Labor pains and opioids delay gastric emptying and promote emesis
CNS changes
Increase in endorphine (higher pain threshold)
Increased sensitivity to IAs, LAs, and opioids (decreased anesthetic requirements)
MAC requirements decrease by ___% in parturients
40%
Renal Changes
Increase in RBF and GFR d/t increased CO
Increased creatinine clearance – because of this, lower serum BUN/Cr & uric acid values
increased excretion of glucose and bicarb (compensation for resp alkalosis)
Formula for Uterine Blood Flow
(Uterine arterial BP - Uterine Venous BP) / (Uterine vascular resistance)
Normal uterine blood flow at term
500-700cc/min
Why is maternal hypotension such a big deal?
The uterine vascular bed lacks autoregulation!!!! Maternal UBF is dependent on BP and CO
Factors that increase uterine vascular resistance, and thus decrease UBF
Oxytocin, contractions, ketamine, abruptio placentae, and severe HTN)
Drug transfer across the placenta depends on
MW Size Lipid Solubility Maternal drug concentration Maternal and fetal pH (more non-onized means more transfer) Low protein binding