Physiologic Changes in Pregnancy

Question 1

How much total gain in plasma volume during pregnancy?

Answer 1

1.1 - 1.6 L

*Systemic vasodilation activates RASS system to hold onto fluid

Question 2

What is tachycardia in pregnant women?

Answer 2

110-120

Question 3

How much does cardiac output increase by in the third trimester? How?

Answer 3

30-50%
Increased heart rate
Retaining volume

Question 4

Why does Creatinine go down?

Answer 4

With increased CO, kidney’s see more fluid, GFR is increased by 50%

Question 5

How does pregnancy effect the respiratory system?

Answer 5

fetus displaced diaphragm by 5 cm
Decreases expiratory reserve volume
Decreases Function residual capacity
Progesterone- abdominal wall muscles relax, allows rib cage to expand more than usual - increased inspiratory volumes

Total lung capacity remains the same

Tidal volume overall increased

Question 6

Why do you see slight hydroureter in pregnant women?

Answer 6

Increased progesterone
Decreased smooth muscle transit/ peristalsis
Decreased movement of ureter
= hydroureter

Question 7

Pregnancy has increased metabolic demands and therefore requires an increased oxygen. How does the body accomplish this?

Answer 7

increased respiratory rate
need increased minute volume (tidal volume x respiratory rate)
Increased oxygen uploading- also means increased CO2 offloading - causes alkalosis
**RESPIRATORY ALKALOSIS**

Question 8

Why GERD in pregnancy?

Answer 8

Progesterone and relaxin = relax smooth muscle > sphincter is more loose

Question 9

Anemia definition in First and third trimester?

Answer 9

< 11

Question 10

Anemia definition in second trimester?

Answer 10

< 10.5

Question 11

Daily Fe requirement during prengancy?

Answer 11

1,000 mg

Question 12

What happens to cardiac output in pregnancy?

Answer 12

Increases

CO = HR x SR
(increased HR and increased volume)

Question 13

What happens to systemic vascular resistance in pregnnacy?

Answer 13

Decreases by 21%

Question 14

What happens to pulmonary vascular resistance in pregnancy?

Answer 14

Decreases by 34%

Question 15

What is the usual acid-base status of pregnancy?

Answer 15

Slight respiratory alkalosis

Question 16

Functional residual capacity in pregnancy

Answer 16

Decreases

FRC = after a regular breath, how much is left over in the lungs + residual volume (what you can’t get out of your lungs)

Think because the diaphram is displaced upward 5 cm (less room for residual air to sit in there), responsible for more shallow breathing

Question 17

Inspiratory Capacity in Pregnancy

Answer 17

INCREASES

Progesterone and relaxin prevent smooth muscle from contracting (abdominal wall/rib cage) relaxes → inspiratory capacity increases because you can expand chest wall more than you ever could before

Question 18

Residual Lung Volume in Pregnancy

Answer 18

DECREASES!

Think about the diaphram, it is elevated, less room for resdiual in there!

Question 19

Tidal Volume in Pregnancy

Answer 19

Tidal Volume = the amount of air that moves in or out of the lungs with each respiratory cycle

TIDAL VOLUME INCREASES

Question 20

Respiratory rate in pregnancy

Answer 20

Increased respiratory rate

increased minute volume = tidal volume x respiratory rate

tendency towards tachynpea > increased CO2 offloading > respiratory alkalosis

Question 21

How much does plasma volume increase by in pregnancy?

Answer 21

1.5 L

Question 22

Pulmonary Changes in Pregnancy - things that decrease

Answer 22

Residual Volume (RV)

Expiratory Reserve Volume (ERV)

Function Residual Capacity (FCR)

Total Lung Capacity (TLC)

Take the RV down to the ER(v) for some TLC because it’s FR(c)ee

Question 23

Pulmonary Changes in Pregnancy - things that increase

Answer 23

Inspiratory Capacity (IC)

Tidal Volume (TV)

I See (IC) the TV

Question 24

Pulmonary Changes in Pregnancy - things that DONT change

Answer 24

Vital Capacity (VC)

Inspiratory Reserve Volume (IRV)

Question 25

What is a NORMAL physiologic change of pregnancy that may be reflected on an arterial blood gas analysis

Answer 25

Respiratory Alkalosis