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- | =Maternal-Fetal Physiology=
| + | OjTKwZ Very informative post.Really looking forward to read more. |
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- | ==Objectives==
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- | *List pertinent physiologic changes in various maternal systems
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- | *Recognize that signs and symptoms in a pregnant patient are often more difficult to interpret
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- | *Non-pregnant lab values and measurements are frequently abnormal in the pregnant state
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- | ==First Trimester==
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- | *21 y/o G1P0 at 8w0d by L=6 week US at the (WVC) presents for her OB registration appointment.
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- | **She denies any LOF (leaking of fluid), VB (vaginal bleeding).
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- | **Pt with C/C of cramping and dark “poop”, nausea and vomiting with heart burn.
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- | *PMH: Denied
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- | *PSxH: Denied
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- | *OB: G1
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- | *Gyn: Denied
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- | *Social Hx: Denied x 3
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- | *Allergies: NKDA
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- | *Medications: PNV (Prenatal Vitamin)
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- | *VS: BP: 110/80 P: 80 T: 98.6 Weight: 65Kg Height: 5’1 UA: WNL
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- | *PE: WNL
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- | *GI:
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- | **Constipation:
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- | ***Mechanism: ferrous-sulfate in the pre-natal vitamins slows GI motility
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- | ***Tx: give colace
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- | **Nausea and Vomiting:
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- | ***beta-HCG (peaks 10-12 weeks)
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- | ***progesterone: a smooth muscle relaxant; causes decreased bowel movement which can lead to increased time for water reabsorption and thus constipation
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- | ***decreased GI motility
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- | **weight gain:
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- | ***average Weight Gain
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- | ****Normal Weight for Height: about 20 lbs
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- | ****Underweight Women: about 30 lbs
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- | ****Overweight Women: about 16 lbs
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- | ==Second Trimester==
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- | *21 y/o is now 20 weeks pregnant
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- | *Presents to triage at Wishard with horrible heartburn after eating a deep fried twinkie at the state fair.
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- | *She threw-up so much in early pregnancy that she is making up for it now. She has gained 25 lbs.
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- | *She denied any LOF (leaking of fluid), denied VB (vaginal bleeding) or cramping.
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- | *She stated that she had some of the chalkie things and it didn’t make it better this time.
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- | *She was given a GI cocktail in triage and she was still miserable.
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- | *Differential Diagnosis:
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- | **Constipation
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- | ***Small bowel obstruction
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- | **Gallstones
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- | **Pancreatitis
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- | **Appendicitis
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- | ==First / Second Trimester GI Issues==
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- | *Estrogen / Progesterone Gallstones
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- | *Recall that progesterone is a smooth muscle relaxant.
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- | *Recall that progesterone is at high levels throughout pregnancy to maintain the uterine environment.
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- | *High circulating levels of progesterone can lead to:
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- | **Increased GERD from relaxation of GE sphincter
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- | **Constipation from delayed transit through large bowel
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- | **Increased N/V from delayed gastric emptying
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- | **“Full stomach” sensation
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- | *During pregnancy, the appendix is moved medially such that appendicitis pain will present mid-quadrant.
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- | ==Second / Third Trimester GI Issues==
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- | *21 y/o G1P0 at 28w0d
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- | *Presents to triage at St. Francis Beech Grove.
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- | *Patient has been brought in by her family “Doc I feel horrible. I am dizzy. I was sitting at the high-school football game, I stood up to cheer, my heart started racing and I felt like I was going to pass-out! My ankles are swollen and I feel horrible."
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- | *Denies LOF (leaking of fluid), VB (vaginal bleeding), CTXs (contractions).
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- | *Endorses +FM.
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- | *ED doctor noticed that she is breathing deeply.
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- | *Pertinent Vitals:
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- | **BP: 100/60
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- | **P: 90
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- | **T: 98.6
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- | **RR: 16
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- | **O2: 96% RA
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- | **Weight: 80kgs
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- | *Labs ordered:
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- | **CBC w/platelets, CXR (chest xray), ABG, UA (urinary analysis), CMP (complete metabolic panel), Coags (coagulation studies)
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- | What is ABG?
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- | *PE:
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- | **Lungs: CTA B
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- | **CV: Systolic murmur
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- | **Abd: Gravid, NT
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- | **Extrem: +1 pitting edema
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- | *Lab results:
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- | **WBC: 10, 000 (slightly elevated)
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- | **Hgb/HCT: 10.5/31.7% (decrease)
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- | **Platelets: 200,000 (slight decrease)
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- | **Fibrinogen: 600 (increased)
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- | **Bun / Cr= 3/0.6 (decreased)
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- | **PH: 7.44,
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- | **pCO2: 30
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- | **BiCarb: 21
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- | **paO2= 103
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- | *Are all these values normal or abnormal?
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- | ===Blood pressure in pregnancy===
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- | *Pt blood pressure: 100/60
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- | *Both systolic and diastolic BP decrease in 2nd trimester
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- | *Systalic decreases 5-10 mmHg
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- | *Diastolic decreases 10-15 mmHg
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- | *Normal
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- | ===Pulse in pregnancy===
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- | *Pt's pulse: 90
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- | *Increases 20 beats (peak at 32 weeks, middle of 3rd trimester)
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- | *Normal
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- | ===Cardiac output in pregnanc===
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- | *Recall that cardiac output (CO) is stroke volume (SV) multiplied by the heart rate (HR).
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- | *CO increases at ''8 weeks'' and peaks at ''20 weeks''.
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- | *CO increases by 30-50%
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- | *CO rises to 4.5-6.0 L / min (compared to a normal of...)
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- | How do we know her stroke volume?
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- | *Systolic ejection murmur is common (90% of women).
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- | *S3 gallop is common (90% of women).
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- | *'''Peripheral vascular resistance falls during pregnancy, too.'''
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- | ===Respiratory rate in pregnancy===
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- | *Recall your standard respiratory volumes (see image below).
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- | *'''Note that O2 demand (consumption) is increased by 15-20% in pregnancy.'''
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- | *These volumes are affected by the displacement of the diaphragm rostrally.
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- | *Note that '''respiratory rate should remain unchanged''' in normal pregnancy.
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- | **This is possible because the tidal volume increases (because the minute ventilation increases).
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- | http://www.glowm.com/resources/glowm/graphics/figures/v3/0260/004f.gif
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- | http://www.glowm.com/resources/glowm/graphics/figures/v3/0260/001f.gif
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- | *So '''dyspnea ''is'' normal with pregnancy'''.
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- | {|border=1
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- | !Volume (mL)
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- | !Definition
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- | !Non-pregnant
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- | !Pregnant
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- | !Change
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- | |-
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- | !Total lung capacity
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- | |Vital capacity + residual volume
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- | |4200
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- | |4000
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- | | -4%
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- | |-
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- | !Vital Capacity
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- | |Total lung capacity - residual volume
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- | |3200
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- | |3200
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- | | 0%
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- | |-
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- | !Inspiratory Capacity
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- | |Vital capacity - expiratory reserve volume
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- | |2500
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- | |2650
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- | | +6%
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- | |-
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- | !Tidal volume
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- | |Volume moved in and out with each normal breath
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- | |450
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- | |550
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- | | +33%
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- | |-
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- | !Expiratory Reserve Volume
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- | |Vital capacity - inspiratory capacity
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- | |700
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- | |550
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- | | -20%
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- | |-
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- | !Inspiratory Reserve Volume
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- | |Inspiratory capacity - total volume
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- | |2050
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- | |2050
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- | | 0%
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- | |-
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- | !Residual volume
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- | |Total volume - vital capacity
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- | |1000
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- | |800
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- | | -20%
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- | |-
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- | !Functional Residual Capacity
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- | |Residual volume + expiratory reserve volume
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- | |1700
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- | |1350
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- | | -20%
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- | |}
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- | ===ABG in pregnanc===
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- | *Pt's ABG was ?
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- | *PH: 7.44
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- | *pCO2: 30
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- | *BiCarb: 21
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- | *paO2: 103
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- | *Acidic?
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- | *Basic
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- | *Hyperventilate?
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- | *Hypoventilate?
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- | ===Respiratory System in pregnancy===
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- | *ABGs: PH= 7.40, PCO2=26-32, BiCarb= 18-21, PO2= 101-106
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- | *Pertinence: Relative Hyperventilation:
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- | **O2 consumption increases by 15-20%, minute ventilation increases to a greater degree
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- | *Pertinence: Relative Hyperventilation
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- | **Leading to decreased pCO2
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- | *Relative Respiratory Alkalosis (26-32)
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- | **PH is usually slightly alkaline (7.40-7.46) due to renal excretion of HCO3 (serum 18-21 (+/-) 1.6 lowers the serum bicarb)
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- | **Hyperventilation and increased O2 carrying capacity, pO2 is slightly elevated (106-108)
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- | *Pertinence: A normal pO2 in a pregnant patient is frequently abnormal
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- | *Changes in ABG
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- | {|border=1
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- | !Measure
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- | !Non-pregnant
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- | !Pregnant
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- | !Change
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- | |-
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- | !pH
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- | |7.38 - 7.42
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- | |7.4 - 7.46
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- | |Looser
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- | |-
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- | !pCO2 (mmHg)
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- | |38 - 45
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- | |26 - 32
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- | |Lower
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- | |-
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- | !pO2 (mmHg)
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- | |70 - 100
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- | |101 - 106
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- | |Lower
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- | |-
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- | !HCO3- (mEq / L)
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- | |24 - 31
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- | |18 - 21
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- | |Higher
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- | |-
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- | !O2 saturation (%)
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- | |95 - 100
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- | |95 - 100
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- | |None
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- | |}
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- | *Importance:
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- | **A normal pregnant woman has a compensated respiratory alkalosis and a diminished pulmonary reserve.
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- | **Respiratory Alkalosis with a compensatory metabloic acidosis.
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- | *Cause:
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- | **Progesterone
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- | **Diaphragm raised 4cm
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- | ===CBC in pregnancy===
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- | *Plasma Volume and RBC Mass
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- | **Plasma volume increases by about 50%
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- | **RBC volume increases by about 30%
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- | *Result:
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- | **“Physiologic anemia of pregnancy”
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- | **The mean Hgb is about 11.5 g/dl
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- | ===Coagulation in pregnancy===
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- | *In pregnancy the pt is hypercoaguable
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- | *Procoagulant’s are increased: I, VII, VIII, IX, X and Fibrinogen.
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- | *Prevents Peripartum Hemorrhage
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- | ===Renal System in pregnancy===
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- | *Bun & Serum Creatinine decreases by about 25%
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- | *Plasma osmolarity decreases by about 10 mOsm / kg H20
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- | *Increase in tubal reabsorption of sodium
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- | *Marked increase in renin and angiotensin levels
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- | **But markedly reduced vascular sensitivity to their hypertensive effects
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- | *Increased glucose excretion
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- | *Anatomic:
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- | **Kidney size increases
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- | **Kidney weight increases
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- | **Ureteral dilation (right side greater than left side)
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- | **Bladder becomes an intra-abdominal organ
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- | *Hemodynamic:
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- | **GFR increase by 50%
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- | **Renal plasma increased by flow by 75%
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- | **Creatinine Clearance increases to 150-200 cc / min
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- | *Swollen Ankles:
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- | **Recall that the Plasma Volume Increases 50% in pregnancy.
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- | **Recall that there is decreased Systemic Vascular resistance in pregnancy.
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- | **Recall that there is renal retention of Na and H20 in pregnancy.
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- | ***Leads to a total increase of 6 – 8 L in total body H20!
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- | ***2 / 3rd extracellular
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- | ***1 / 3rd intravascular
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- | ***Intravascular increase is put in the "dependent" (affected by gravity) areas like the lower venous system.
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- | ==Caring Family==
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- | *The patient’s husband lies her flat in an effort to keep her comfortable.
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- | *The fetus’s FHT’s drop to 80.
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- | *But, the ROCK STAR medical student wedges the patient quickly on her left side and the FHT’s recover quickly!
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- | *What happened?
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- | *Gravid Uterus placed pressure on the IVC that in turn decreased “utero-placental blood flow.”
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- | *Regional Blood Flow Redistribution:
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- | **Cardiac output falls
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- | **Blood is shunted '''to the brain''' and
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- | **Blood is shunted '''away from the uterus and placenta'''
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- | **This causes a ''reflex fetal bradycardia''
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- | ==Importance of Physiology==
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- | *All can be abnormal in the Non-Pregnant state:
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- | **Decreased BP
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- | **Swollen ankles
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- | **CXR cardiomegaly with a leftward deviation
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- | **Systolic Ejection murmur
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- | **Dyspnea
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- | **Anemia
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- | **Hypercoaguable
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- | **NORMAL for Pregnancy
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- | ==Maternal Physiology Review==
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- | http://mypages.iu.edu/~pbaenzig/medschoolfiles/icm/obgyn/Pages_from_111202_OBGYN_4_Maternal_Fetal_Physiology_Slides.png
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OjTKwZ Very informative post.Really looking forward to read more.