1
Q
Term gestation is defined as occurring between _____ weeks.
A
37-40
2
Q
Parturient
A
A patient who is currently in labor or has recently given birth.
3
Q
The total number of pregnancies a woman has had, regardless of the fetal outcome, is known as _____.
A
Gravida
4
Q
The number of births occurring after 20 weeks of gestation, regardless of outcome, is known as _____.
A
Para
5
Q
Interpret the obstetric shorthand $G1P0$.
A
Primigravida / Nulliparous (first pregnancy, zero births past $20$ weeks).
6
Q
What is the minimum expected healthy weight gain for a pregnant woman in kilograms?
A
~12 kg
7
Q
What is the recommended total weight gain for a woman with a normal pre-pregnancy BMI (18.5-24 kg/m^2)?
A
25-35 lb
8
Q
What is the recommended total weight gain for a woman with an obese pre-pregnancy BMI (> 30 kg/m^2)?
A
11-20 lb
9
Q
What is the expected rate of weight gain per week for a pregnant patient with a normal BMI?
A
1 lb/wk
10
Q
At approximately how many weeks gestation do hormonal changes begin to decrease Systemic Vascular Resistance (SVR)?
A
Around 6 weeks.
11
Q
What percentage decrease in Systemic Vascular Resistance (SVR) is expected from pre-pregnancy levels by term?
A
~20%
12
Q
List the four primary hormones that lead to maternal vasodilation.
A
Progesterone, Prostacyclin, Relaxin, and Estrogen.
13
Q
Maternal physiology is characterized as a high flow, _____ resistance state.
A
low
14
Q
What is the typical percentage increase in total blood volume by term?
A
30-35%
15
Q
Between which weeks of gestation does the maternal blood volume typically plateau?
A
32-34 weeks.
16
Q
How does the expansion of plasma volume compare to the expansion of red blood cell (RBC) volume in pregnancy?
A
Plasma volume expansion is significantly greater than RBC volume expansion.
17
Q
What is the protective purpose of the increased blood volume during pregnancy?
A
It protects against blood loss during delivery.
18
Q
How much blood loss occurs during vaginal vs C/S?
A
500 mL vaginal
800 mL C/S
19
Q
How long after delivery does it typically take for blood volume to return to pre-pregnancy levels?
A
Within 6 weeks.
20
Q
What is the average blood volume (BV) of a pregnant woman at term in ml/kg?
A
~85-90 ml/kg
21
Q
By term, maternal cardiac output (CO) typically increases by what percentage?
A
~40%
22
Q
Which component of cardiac output (CO) begins to increase first, around 6 weeks of gestation?
A
Heart Rate (HR)
23
Q
Which component of cardiac output (CO) begins to increase around 8-10 weeks of gestation?
A
Stroke Volume (SV)
24
Q
What is the most dominant factor that sets the stage for an increased maternal Stroke Volume (SV)?
A
The early drop in Systemic Vascular Resistance (SVR).
25
In the Renin-Angiotensin-Aldosterone System (RAAS) during pregnancy, increased aldosterone leads to increased Na+ reabsorption and _____.
water retention
26
What is the non-pregnant baseline for Uterine Blood Flow (UBF)?
~50 ml/min
27
What is the estimated Uterine Blood Flow (UBF) at term gestation?
~700 ml/min
28
By what factor does skin blood flow increase during pregnancy?
3-4x
29
What percentage increase in Left Ventricular (LV) mass is expected by term?
50%
30
The ventricular hypertrophy observed in pregnancy is categorized as _____ hypertrophy.
eccentric (Athlete’s Heart)
31
In which anatomical directions does the heart shift during pregnancy due to diaphragmatic elevation?
Anterior and to the left.
32
Where does the Point of Maximal Impulse (PMI) shift to in a pregnant patient?
Up and to the left (4th intercostal space, midclavicular line).
33
What direction does the QRS axis shift on an EKG during the 3rd trimester?
Leftward
34
Which EKG lead commonly shows T wave inversions during normal pregnancy?
Lead III
35
What change occurs to the PR interval on an EKG during pregnancy?
It is shortened d/t increased sympathetic activity in 3rd trimester - accelerated AV node conduction velocity
36
Which leads are positive and negative in pregnancy?
Positive: 1 and aVL
Negative: 2 and aVF
37
What is the most common EKG abnormality observed in the pregnant patient?
Tachydysrhythmias (Sinus tachycardia, PACs, PVCs).
38
Which two cardiac valves show regurgitation in over 90% of pregnant patients?
Tricuspid and pulmonic valves.
- MR ~ 25-30%
39
Which heart sound, often called a ventricular gallop, is commonly heard in the 3rd trimester?
3rd heart sound (S3), occurs d/t rapid filling of relaxed ventricle
40
Which heart sound which is less common and can be pathological disseears at term?
4th heart sound, indicates stiff ventricle
41
Where is the Grade II Systolic Ejection Murmur (SEM) best auscultated in a pregnant patient?
The right side of the heart near the sternal border.
42
What term describes the compression of the inferior vena cava and aorta by the gravid uterus when the patient is supine?
Aortocaval compression (Supine Hypotensive Syndrome).
43
As early as which week range can aortocaval compression occur?
13-16 weeks gestation.
44
Initial maternal symptom of aortocaval compression?
Tachycardia initially then bradycardia, n/v, pallor, loss of consciousness, fetal distress
45
Describe the patho of aortocaval compression
1. Decreased venous return to right atrium
2. Decreased CO
3. Hypotension
4. Decreased uterine blood flow
5. Decreased perfusion to fetus
46
What is the gold standard for relieving aortocaval compression in the clinical setting?
Left Uterine Displacement (LUD).
47
Approximately how much blood is autotransfused from the uterus into general circulation with each contraction?
300 to 500 mL
48
How does CO change during the first stage of labor?
Increases b/w and during contractions d/t inc in preload from autotransfusion of uterine blood and increased HR
49
By what percentage does cardiac output CO increase during pushing efforts in the 2nd stage of labor?
~50%
pushing efforts, SV inc and HR inc
50
What is the peak percentage increase in cardiac output CO observed in the immediate postpartum period? How long does it last?
60% to 80%
dec after 10 min, normal w/i 24 hours
51
Why does cardiac output (CO) spike dramatically immediately after delivery?
Relief of caval pressure and autotransfusion as the uterus continues to contract.
52
Why is airway management more difficult in the pregnant patient regarding tissue characteristics?
The airway is often edematous and the tissue is friable. Nosebleeds/rhinitis
53
What adjustment to Endotracheal Tube (ETT) size is generally recommended for the pregnant patient?
Use a smaller tube (6.0 or 6.5 mm)
54
Which airway instrumentation routes should be avoided in the pregnant patient due to friable tissue?
Nasal routes (Nasal tubes, nasal trumpets, NGT).
55
Which airway assessment classification may worsen significantly during the course of labor?
Mallampati class
56
What are the hormone changes caused by estrogen?
Inc number and sensitivity of progesterone receptors in brain's respiratory center
57
How does progesterone affect the brain's respiratory center sensitivity to CO?
It increases sensitivity to CO2
58
What respiratory passage changes are induced by progesterone?
Bronchodilation and hyperemia/edema.
59
What effect does relaxin have on the maternal rib cage?
It causes ligamentous attachments to the lower ribs to relax
- subcostal angle inc
- widened AP and transverse diameter of chest wall
- chest height is shortened, but AP dimensions increase (barrel-shape)
- Preserves Total lung capacity (TLC)
60
Functional Residual Capacity
FRC
Volume of air that prevents complete emptying of lungs and keeps small airways open
61
Expiratory Reserve Volume ERV
The extra volume of air that can be expired with maximum effort beyond the level reached at the end of a normal expiration.
62
Residual Volume RV
The volume of air that remains in the lungs after a maximum expiratory effort.
63
Functional Residual Capacity FRC decreases by what percentage at term?
20%
64
The decrease in Functional Residual Capacity (FRC) is a result of decreases in which two specific lung volumes?
Residual Volume (RV) and Expiratory Reserve Volume (ERV).
65
What physiological change leads to the earlier closure of small airways in the pregnant patient?
The elevated diaphragm leads to increased pleural pressure (less negative), reducing outward distending force.
66
Why does the supine position exacerbate the risk of small airway closure in the pregnant patient?
The diaphragm is elevated even more, leading to increased alveolar atelectasis.
67
What is the clinical consequence of the closing capacity exceeding the Functional Residual Capacity FRC?
Small airway closure and increased vulnerability to hypoxia and V/Q mismatch
68
Why do pregnant patients desaturate faster during periods of apnea or distress?
Reduced oxygen reserves due to decreased Functional Residual Capacity (FRC).
69
What is the most vital step before the induction of anesthesia in a pregnant surgical patient?
Pre-oxygenation
70
Gravida refers to the number of pregnancies regardless of fetal outcome. Para refers to the number of births after _____ weeks.
20
71
What are the quickest ways to pre-oxygenate?
- 3-5 VC breaths w/ tight face mask seal 100% O2
- 8 deep breaths at an O2 flow rate of 10 L/min over 60 sec
72
What happens to the heart's position as the diaphragm is pushed upward by the gravid uterus?
It is displaced anteriorly and to the left.
73
Maternal stroke volume SV begins to increase between weeks _____ of gestation.
8-10
74
The high flow, low resistance state of pregnancy is partly due to the low resistance of the _____ circulation.
placental
75
Which EKG interval is shortened in the 3rd trimester due to accelerated AV node conduction?
PR interval
76
Autotransfusion during labor occurs when blood is moved from the _____ to the general circulation.
uterus
77
A Grade II SEM (murmur) in pregnancy is typically due to _____.
cardiac enlargement
78
Why should nasal trumpets be avoided in parturients?
Increased risk of epistaxis (bleeding) due to friable, edematous airway tissue.
79
Which respiratory volumes increase during pregnancy?
VT and IC
80
Which respiratory volumes are unchanged during pregnancy?
TLC and VC
81
Oxygen consumption increases by ___% at term. Why?
20% increase
1. Increased metabolism (metabolic needs of fetus, uterus & placenta)
2. Increased work of breathing
3. Increased cardiac workload
82
Why does pregnancy cause dyspnea?
Begins in 1st trimester
- Increased respiratory drive
- Increased O2 consumption
- Decreased PaCo2
- Larger pulmonary blood volume
- Anemia
- Nasal congestion
83
How are minute ventilation and alveolar ventilation change from pregnancy?
Minute Ventilation Increases
- RR 1-2 breath per minute increase (Hormone-mediated: inc neural drive to breathe)
- Tidal volume increase
Alveolar Ventilation Increases
84
How do blood gasses change in pregnancy?
Respiratory alkalosis
- PaCO2 decreases ~8-10 mmHg
- PaO2 increases ~5 mmHg
- Bicarb ~ 20 mEq
- Base excess 2-3 mEq/L
85
What are the pulmonary changes in labor?
1st: Vm up 140%
2nd:
- Vm up to 200%
- Maternal CO2 dec 10–15 mmHg
- O2 consumption inc
- Aerobic req inc
- Maternal lactate level inc
- May need supplemental O2
86
What is the primary cause of 'physiologic anemia' during pregnancy?
Plasma volume increases to a greater extent than red cell mass.
87
By how much does hemoglobin typically drop from pre-pregnancy to 36 weeks’ gestation?
Approximately 2.4 g/dL.
88
What is the typical percentage decrease in hematocrit during pregnancy?
Approximately 6.5%
89
A maternal hemoglobin concentration below what value is considered abnormal?
11 g/dL.
90
If hemoglobin is >13 g/dL in mid to late pregnancy, what condition should be evaluated according to ACOG?
Pre-eclampsia (due to hemoconcentration).
91
What is the standard treatment for iron deficiency anemia in pregnancy?
Oral iron formulations.
92
What is the normal platelet count range for a non-pregnant individual?
165,000 to 415,000 mm^3
93
At what platelet count is a pregnant patient diagnosed with thrombocytopenia?
Less than 150,000/mm^3
94
Which form of pregnancy-related low platelets is non-pathologic and resolves after delivery?
Gestational thrombocytopenia
95
What is the underlying mechanism of Immune Thrombocytopenic Purpura (ITP)?
Autoimmune platelet destruction.
96
What serious complication is a risk when performing neuraxial techniques on a patient with low platelets?
Epidural hematoma
97
What is the generally accepted minimum platelet count for safe neuraxial anesthesia in stable obstetric patients?
80,000/mm^3
98
What type of anesthesia is indicated for an emergency C-section if no laboratory results are available to check platelet status?
General Endotracheal Anesthesia (GETA).
99
At what platelet count should a surgery or procedure generally be cancelled?
$10,000/mm^3$.
100
What is the target minimum platelet count recommended before major surgery?
50,000/mm^3
101
Which specific coagulation factors do NOT increase in concentration during pregnancy?
Factors II, V, XI, and XIII
102
What happens to the concentration of Factor I (Fibrinogen) at term gestation?
It increases significantly to >400 mg/dL
103
Name the coagulation factors that increase at term gestation besides Factor I.
Factors VII, VIII, IX, X, or XII.
104
Which coagulation factors don't change at term gestation?
Factors II and V
105
Which two coagulation factors actually decrease at term gestation?
Factors XI and XIII.
106
By what percentage do Prothrombin Time (PT) and Partial Thromboplastin Time (PTT) decrease during pregnancy?
Approximately 20%
107
What change occurs in fibrinolytic activity during the third trimester?
Fibrinolytic activity decreases.
108
What is the typical range for White Blood Cell (WBC) count during pregnancy?
9,000 to 11,000/mm^3
109
How high can the White Blood Cell (WBC) count reach during labor?
Up to 34,000/mm^3
110
Which specific immune cell function is impaired during pregnancy, increasing infection risk?
Polymorphonuclear leukocyte function.
111
The decrease in humoral antibody titers during pregnancy primarily affects which types of viruses?
Measles, influenza A, and herpes simplex.
112
In terms of aspiration risk, how should all parturients be clinically managed?
As if they have a full stomach.
113
What change occurs in the Lower Esophageal Sphincter (LES) during pregnancy?
The competence and tone decrease.
114
When is the Lower Esophageal Sphincter (LES) tone at its lowest point?
At term.
115
How long after delivery does the Lower Esophageal Sphincter (LES) tone typically return to normal?
Around 4 weeks postpartum.
116
What happens to gastric emptying specifically during labor?
It becomes delayed.
117
For how long postpartum should patients still be treated as having a full stomach?
4 to 6 weeks.
118
What are the two specific gastric criteria that define a high risk for aspiration pneumonia?
Gastric pH < 2.5 and gastric volume >25 mL.
119
What is Mendelson’s Syndrome?
Inflammatory response of the lung parenchyma following perioperative aspiration of gastric contents.
120
What significant changes occur in liver size and hepatic blood flow during normal pregnancy?
There is little to no change.
121
Pregnancy increases pressure in the portal and splanchnic veins, which raises the risk for what gastrointestinal complication?
Esophageal varices
122
Name the 3 liver-related enzymes that are normally increased in a healthy parturient.
Serum aspartate aminotransferase (AST), lactic dehydrogenase (LDH), or alkaline phosphatase.
- also cholesterol
123
Why is edema common in pregnancy regarding hepatic protein production?
Decreased total protein and albumin lead to a drop in colloid oncotic pressure.
124
By what percentage does pseudocholinesterase activity decrease before delivery?
25%
125
When does pseudocholinesterase activity reach its lowest point postpartum?
On the third postpartum day (decreased by 33%
126
Is the pregnancy-related decrease in cholinesterase activity typically enough to cause prolonged paralysis from succinylcholine?
No, it is usually not enough for a single dose.
127
What are the primary symptoms of pregnancy-related cholestasis?
Pruritus, high serum bilirubin, and abnormal liver function tests.
128
By what percentage does renal blood flow increase during pregnancy?
75%
129
What is the typical serum creatinine level at term?
~0.5-0.6 mg/dL.
130
A creatinine clearance, BUN, and serum clearance values below what level suggests abnormal renal function in pregnancy?
- Creatinine clearance < 100 mL/min
- BUN > 15 mg/dL
- Serum creatinine > 1 mg/dL
131
What happens to Blood Urea Nitrogen (BUN) levels during pregnancy?
BUN levels decrease ~ 8-9 mg/dL at term
132
Why is glucosuria (glucose in urine) sometimes seen in normal pregnancy?
Tubular glucose reabsorption cannot keep up with the increased Glomerular Filtration Rate (GFR).
133
What level of protein in a 24-hour urine collection is indicative of pre-eclampsia?
>/= 300 mg in 24 hrs
134
By how much does the thyroid gland enlarge during pregnancy? What is the treatment for hypothyoid?
50-70%
increased potential for difficult airway
hypothyroid = synthroid (levothyroxine)
135
How does adrenal function change in pregnancy?
Inc cortisol: 100% in 1st trimester, 200% term
- plasma endorphins inc
136
Which hormone, produced by the placenta, is responsible for increased insulin resistance?
Human placental lactogen.
137
By what percentage does maternal cortisol increase by term?
200%
138
What is the purpose of increased Prolactin secretion during pregnancy?
Preparation for breastfeeding.
139
What percentage increase in Oxytocin secretion is seen by term?
30%
140
Name two primary functions of Oxytocin in the parturient.
Stimulating uterine contractions and breast milk letdown.
141
The hormone Relaxin increases joint mobility but also contributes to what common pain?
Sacroiliac or knee pain.
142
What nerve is compressed in the condition known as Meralgia Paresthetica?
Lateral femoral cutaneous nerve.
143
What musculoskeletal change results from the shift in the center of gravity and anterior pelvic tilt?
Lumbar lordosis.
144
How does the pain threshold change during pregnancy?
It increases due to plasma endorphins and progesterone effects.
145
What change in the epidural space increases the risk for venous puncture during epidural placement?
Engorgement of epidural veins.
146
What happens to the volume of Cerebrospinal Fluid (CSF) during pregnancy?
CSF volume decreases.
147
How does pregnancy affect the required dose of local anesthetic for spinal or epidural blocks?
A lower total dose is required to produce the same level of block.
Advanced Principles A
flashcards
Decks in class (11)
# Cards
