Maternal Physiology pt3 Flashcards
Why are all parturient patients are considered to be full stomach?
- Enlarged gravid uterus displaces stomach cephalad
- Increased gastric pressure
- Decreased competence of the LES
significant aspiration risk
How does lower esophageal sphincter tone change throughout pregnancy?
- Tone decreases throughout pregnancy with the lowest tone occurring at term.
- LES tone normalizes at 4 weeks post-partum.
(remain aspiration risk for up to 4 weeks postpartum)
What is Mendelson’s Syndrome?
Aspiration pneumonitis & inflammatory response of lung parenchyma
What puts one at high risk of Mendelson’s syndrome? What is the primary preventative intervention for pregnant patients?
- pH < 2.5
- > 25mL gastric volume
Bicitra given to pregnant patients before delivery to neutralize gastric pH.
Uterus takes ____ weeks to return to normal size. The LES tone returns to normal around ________? What are the anesthesia implications in the postpartum period?
- Uterus takes 6 weeks to return to normal size
- LES tone returns to normal around 4 weeks.
Treat as full stomach for 4-6 weeks postpartum
What changes occur in the liver during pregnancy?
↑ risk of esophageal varices due to increased splanchnic, portal and esophageal venous pressure.
- Careful use of OGT
↑ Liver enzymes and cholesterol (this is normal)
- serum aspartate aminotransferase
- lactic dehydrogenase
- alkaline phosphatase
How is colloid oncotic pressure affected by pregnancy?
Colloid oncotic pressure decreases due to:
- decreased total protein
- decreased albumin to globulin ratio
decreases further after delivery/returns to normal ~6 weeks postpartum
What occurs with pseudocholinesterase levels during pregnancy?
- pseudocholinesterase activity decreases by 25% before delivery
- decreases by 33% on 3rd postpartum day.
- return to normal 2-6 weeks postpartum
Usually not enough decrease in PseudoChE to prolong paralysis after single dose of SCh.
When can cholestasis occur to parturient patients? What factors attribute to cholestasis?
- Occurs during 3rd trimester (1/100 people)
- Cause: biliary stasis and increased bile secretion
Leads to increase risk for cholelithiasis
What are the s/s of cholestasis?
- Pruritis
- ↑ serum bilirubin
- abnormal LFTs
What are the consequences of cholestasis in obstetric patients?
- ↑ risk of cholelithiasis
- may require cholecystectomy
- ↑ risk of cholestasis in subsequent pregnancies
During pregnancy the kidneys see a _____ increase in renal blood flow.
75%
-renal vasodilation
What are the results of increased renal blood flow during pregnancy?
- ↑ GFR
- ↑ Creatinine clearance
- ↓ Creatinine
- ↓ BUN
What BUN/Creatinine levels are typical of pregnant patients?
- BUN: ~8 - 9 mg/dL at term (decreased)
- Serum Creatinine: ~0.5 - 0.6 mg/dL at term (decreased)
What changes in the urine can occur during pregnancy?
- Glucosuria common (tubular Glucose reabsorption can’t keep up with ↑ GFR)
- Proteinuria is common (excessive protein can indicate pre-eclampsia)
What would a finding of proteinuria possibly indicate in a parturient patient?
preeclampsia
What labs in a parturient patient suggest abnormal renal function?
- BUN > 15mg/dL
- Creatinine > 1.0 mg/dL
- Creatinine Clearance < 100 mL/min
Further evaluation required.
What occurs with the thyroid during pregnancy?
Enlargement by 50 - 70%
- increased risk of diff. airway
Hypothyroidism in 10% pts
What are the pancreatic function changes during pregnancy?
- Insulin resistance due to Human placental lactogen
(Hormone that prepares the body for breastfeeding) - Increased blood glucose
How does adrenal function change in the parturient patient?
↑ cortisol
- Increased by 100% in 1st trimester
- Increased up to 200% by term
↑ plasma endorphins
How does the anterior pituitary change during pregnancy?
Hyperplasia of lactotrophic cells ⇒↑Prolactin secretion
- preparation for breastfeeding
- hyperprolacinemia (may l/t acne)
How does the posterior pituitary change during pregnancy?
Oxytocin secretion increases by 30% by term
- Stimulates contractions
- Breast milk letdown
- “Bonding hormone”: Helps mother bond to baby postpartum
What nerves are commonly compressed and lead to nerve pain in pregnancy?
- Sciatic
- Meralgia paresthetica
(compression of lateral femoral cutaneous nerve at location that it exits pelvis)
What is meralgia paresthetica?
Compression of lateral femoral cutaneous nerve at exit site of pelvis
- Affects outer side of thigh
S/s:
* Numbness & Tingling
* Burning pain (lateral aspect of the thigh)
What is the reason for lots of pelvic pain during pregnancy?
Lumbar lordosis which causes:
- Anterior pelvic tilt
- Narrowing of intervertebral spaces.
- Center of gravity changes
What CNS changes occur during pregnancy?
- ↑ CBF
- ↑ BBB permeability
- ↑ pain threshold
What is the mechanism for increased pain threshold for parturient patients?
- ↑ plasma endorphins
- Progesterone activates κ-opioid receptors analgesic mechanisms
What occurs with the epidural space in pregnant women?
- ↑ Venous plexus volume ⇒ engorged veins
- ↓ CSF volume
What is the result of increased venous plexus volume?
Engorged epidural veins
- decreased free volume of epidural space
- higher risk of venous puncture during epidural placement.
What is the result of decreased CSF volume on local anesthetic spread?
- ↑ spread of LA
- drug will reach higher concentration in lower CSF volume (less dilution)
Parturient patients have an increased sensitivity to _______ neuromuscular blockers.
Non-depolarizing.
Roc & Vec
What can happen with succinylcholine administration in a pregnant patient?
Prolonged paralysis due to ↓ pseudocholinesterase activity
- not usually clinically significant with one dose of succinylcholine but can be
What considerations must be made for multiparous patients?
Multiple births may indicate:
- increased risk of bleed
- may have rapid delivery
How is blood flow and perfusion affected with aortocaval compression?
Decreased venous return to right atrium → Decreased cardiac output → Hypotension → Decreased uterine blood flow → Decreased perfusion to fetus
Why is it important to utilize LUD as a primary intervention when patient and fetus in distress?
- IF patient and baby not doing well it may be related to aortocaval compression.
- LUD is a quick fix and can help rule out other pathologies.
What are some causes of thrombocytopenia (Plt <150k) in pregnancy?
- Idiopathic
- hypertensive disorder of pregnancy
- gestational: no plt dysfunction or bleeding
(may be a side effect of pregnancy rather that malignancy)
Low platelets may progress to preeclampsia and to HELLP syndrome
What is the occurrence of epidural hematoma and what are some of the potential side effects?
1:200,000- 1:250,000
Can cause temporary or permanent neurological damage
Is it appropriate to utilize epidural anesthesia for an emergency c section?
Depends on hospital/anesthesia group policy
- If patient is established and received adequate prenatal care, an epidural may be used.
- If patient is not established and no prenatal care, GETA for c section
How is gastric emptying affected with pregnancy?
Gastric emptying mostly unchanged
delayed during labor
For surgery in pregnant patient, if succinylcholine used and need for prolonged relaxation, what is crucial to assess?
Must check twitches before using non depolarizing drug. This may help identify pseudocholinsterase deficiency that would be seen with initial succinylcholine administration.
How does the pituitary size change in pregnancy?
Size increase by 3x
What are some of the effects of release of the hormone Relaxin during pregnancy?
Increased joint mobility
- sacroiliac pain
- knee pain
Overstretching of joints is possible
- caution with exercise/stretching
What physically happens to the kidneys with pregnancy? When do they go back to baseline?
- kidneys enlarge
- back to baseline ~6 weeks postpartum
Untreated thyroid dysfunction in pregnant patients can have what consequences?
- fetal cognitive issues
- spontaneous abortion
- growth restriction
- placental abruption
treated with synthroid
