Exam 4: Pediatric Anesthesia Pt 1 - A&P (Becky M.) Flashcards
(108 cards)
1
Q
Neonates age:
Infants age:
Toddlers age:
A
- Neonate: birth - 1 month
- Infant: 1 month - 12 mos
- Toddler: 12 mos - 3 yrs
2
Q
Preschool age:
School age:
Adolescents:
A
- preschool: 4-6 yrs
- School: 6-13 yrs
- Adolescents: 13-18 yrs
3
Q
What is a LBW?
A
< 2500g
4
Q
What is a VLBW (very low birth weight)?
A
< 1500 g
5
Q
What is an ELBW (extremely low birth rate)?
A
< 1000 g
6
Q
What weight is a micropreemie?
A
< 750 g (0.75kg)
7
Q
What does the fetus rely on for gas exchange?
A
Placenta
8
Q
How does oxygenated blood get to the fetus in utero?
A
Via the umbilical vein
9
Q
What 3 shunts are used for the blood to bypass the lungs?
A
- Ductus Arteriosus (PA - aorta)
- Ductus Venosus (umbilical vein - IVC)
- Foramen Ovale (RA - LA)
10
Q
In fetal circulation, where is most of the blood directed?
A
- brain, coronary arteries (head/neck)
11
Q
Fetal circulation
In fetal circulation, PVR is ____ and SVR is ____.
A
high & low
switches after birth
12
Q
Fetal circulation
What causes the PVR to fall?
A
lungs start expanding & PaO2 rises (pulm. vasodilation)
13
Q
Fetal Circulation
What causes the SVR to increase?
A
Umbilical arteries being clamped
14
Q
Fetal Circulation
What causes the closure of the Foramen Ovale?
A
↑ RAP = changes direction of blood flow = FO closes
15
Q
Fetal Circualtion
What causes the closure of the DA?
What keeps the DA open in utero?
A
↑ SVR & ↓ PVR
- circulating prostaglandins keep DA open in utero
16
Q
When does functional closure of the DA occur?
A
in the 1st 1-8 days
17
Q
When does anatomical closure of the DA occur?
A
In the 1st 1-4 months
18
Q
What can a persistent PDA lead to?
What does intervention does this require?
A
- L → R shunt (lungs overcirculate w/ blood)
- requires pharmacological, surgical, or interventional closure
19
Q
Fetal Circulation
How do we measure the pulse-ox in infants w/ PDA?
A
- pre-ductal (right extremity)
- post-ductal (any other extremity)
20
Q
Fetal Circulation
________ may be given if the PDA needs to remain open after birth.
A
Prostaglandins
Can be life-saving for certain heart defects.
21
Q
CV System
The neonate heart has cellular ________ and fewer ________.
A
- cellular disorganization
- fewer myofibrils
22
Q
CV System
What are the contractile components of the fetal heart that are immature?
What does this mean?
A
- sarcoplasmic reticulum & T-tubules
- neonatal heart cannot ↑ SV
23
Q
CV System
Neonatal myocardial performance is dependent on ____ ________ ________ for contractility.
A
Free Ionized Calcium
give CaCl/gluc to help increase squeeze
24
Q
CV System
Why is bradycardia poorly tolerated in infants?
A
The baroreceptor reflex is poorly developed
they can’t compensate for a low HR
25
# CV System
What autonomic system is predominant in neonates?
What does this lead to?
PSNS
* leads to bradycardia w/ any stress or stimulation (suctioning, laryngoscopy)
26
# CV System
Neonate Normals:
HR:
SBP:
DBP:
HR: 140bpm
SBP: 70-75
DBP: 40
27
# CV System
12 mo normals
HR:
SBP:
DBP:
HR: 120
SBP: 95
DBP: 65
28
# CV System
3 yr old normals:
HR:
SBP:
DBP:
HR: 100bpm
SBP: 100
DBP: 70
29
# CV System
12yr old normals:
HR:
SBP:
DBP:
HR: 80
SBP: 110
DBP: 60
30
# CV System
How can we estimate MAP in preemie babies?
MAP = gestational age
| ex: 25 weeker (MAP = 25mmHg)
31
# CV System
How can we estimate SBP in older kids?
70mmHg + (2 x age)
| ex: 5 yr old = 70 + (2 x 5) = 80mmHg SBP
32
# CV System
What is considered HoTN in a term neonate (0-28 days)?
SBP < 60mmHg
33
# CV System
What is considered HoTN in Infants (1-12mos)?
SBP < 70mmHg
34
# CV System
What is considered HoTN in Children (1-10yrs)?
SBP < 70mmHg
| 70mmHg + (2 x age in yrs)
35
# CV System
What is considered HoTN in kids > 10 yrs old?
SBP < 90 mmHg
36
# Hematology
What is fetal Hgb at birth?
What % of a neonates Hgb is HbF?
18-20g/dL
* 70-90%
37
# Hematology
At what age does an infant experience a physiologic anemia? Why?
* 3-4 mos
* decreased erythropoietin activity and decreased rate of hematopoiesis **(RBCs die & aren't made fast enough)**
38
# Hematology
What is the EBV of a premature neonate?
90-100mL/kg
39
# Hematology
What is the EBV in a newborn (< 1 mo)
80-90mL/kg
40
# Hematology
What is the EBC in a child (> 6 yr)
65-70mL/kg
41
# Hematology
What is the EBC in an infant (1mo-3yr)
75-80mL/kg
42
# Hematology
What is the adult EBV?
65-70mL/kg
43
What type of shift occurs in the oxyhemoglobin curve w/ HbF?
Left shift
* HbF has higher affinity for O2
* facilitates uptake of O2 from mom in utero
44
What is the P50 of HbF?
19mmHg
45
What chains does HbF have?
* 2 alpha & 2 gamma chains
* does **NOT** bind to 2,3 DPG
46
# Respiratory System
When does alveolar ductal development start?
around 24 weeks gestation
47
# Respiratory System
When does **septation** of the air sac begin?
around 36 weeks gestation
| these are basically the formation of alveoli
48
# Respiratory System
Neonatal alveolar SA is ____ of the adult.
Alveoli increase in # & size until age ____.
1/3
8 yrs old
49
# Respiratory System
When does surfactant production & secretion begin? When is the peak?
What cells produce and secrete surfactant?
22-26 weeks gestation
* peak: 35-36 weeks gestation
Type II Pneumocytes
50
# Respiratory System - breathing mechanics
Why do neonates have a pliable chest wall?
lack of muscular development
51
# Respiratory System - Breathing Mechanics
What effects do horizontal ribs have on neonatal breathing?
* less structural assistance for chest wall expansion
* chest wall collapses in - paradoxical breathing pattern
52
# Respiratory System - breathing mechanics
What shape of diaphragm do neonates have?
Flat diaphragm
53
# Respiratory System - breathing mechanics
Why do infants develop respiratory fatigue when they use the intercostal muscles when breathing?
they have less type I muscle fibers (slow twitch muscle fibers resistant to fatigue)
54
# Respiratory System
Neonates/Infants have an ________ metabolic rate & O2 consumption.
Increased
55
# Respiratory System
In neonates, is Vm more dependent on Vt or RR?
RR
* fixed Vt (6-8mL/kg)
56
# Respiratory System
Why do neonates de-saturate rapidly on induction?
1. decreased FRC (structural changes)
2. increased metabolic rate & O2 consumption
57
# Respiratory System
Why are premature newborns more prone to apneic episodes?
Immature respiratory control centers in the brain
| **can lead to bradycardia & cardiac arrest**
58
# Respiratory System
What are the risks of large tongues in kids?
1. airway obstruction
2. lying flat makes it worse
3. more difficult to sweep tongue
59
# Pedi Respiratory Anatomy
What changes are present w/ the larynx?
What are the consequences of this?
* more cephalad (C3-C4 kids)
* creates a more acute angle b/w glottic opening & base of tongue - more challenging view
| Larynx @ C4-C5 in adults
60
# Pedi Respiratory Anatomy
What changes are present w/ the epiglottis?
What are the consequences of this?
Omega-shaped epiglottis
* controlling it w/ the laryngoscope blade can be more difficult
61
# Pedi Respiratory Anatomy
What changes are present w/ the vocal cords?
What are the consequences of this?
* vocal cords more anteriorly slanted
* passing ETT more difficult
62
# Pedi Respiratory Anatomy
How long is the trachea?
What shape is it?
What is the most narrow portion of the trachea/airway?
* ~ 5cm
* funnel-shaped
* cricoid cartilage
63
# Pedi Respiratory Anatomy
Why do we need to be cautious when flexing/extending the neck?
Can displace ETT 1-2cm
**R mainstem or extubation**
64
# Pedi Respiratory Anatomy
What are the angles for mainstem bronchi take off?
both @ 55 degree angle from trachea
65
# Pedi Respiratory Anatomy
Neonates are ________ ________ until about 5 mos old.
What does this facilitate?
nasal breathers
* facilitates breathing while eating
66
# Pedi Respiratory Anatomy
The large occiput and short neck in peds causes what difficulties w/ induction?
* obstruction (neck flexes forward)
* laryngoscopy view difficult
67
# Respiratory System
Airway resistance is ________ ________ to the lumen ________ to a power of 4.
How much does 1mm of airway edema increase resistance?
inversely proportional
radius
16x increase in resistance
68
# CNS
When is myelination complete?
~ 3 yrs old
69
# CNS
What changes are present w/ the NMJ?
* immature NMJ
* Ach Rs function differently
* prolonged channel opening
* immature muscles - more easily depolarized
70
# CNS
When is the neural tube nearly complete?
3-4 weeks gestation
71
# CNS
T/F the BBB is mature at birth.
False
* immature until 1 yr old
| *medications/toxins penetrate BBB*
72
# CNS
Where does the conus medullaris (end of spinal cord) terminate?
* L2-L3 in neonates
* L1 ~8yrs old
73
# CNS
Where does the dural sac end? (until ~ 6 yrs old)
* S2-S3
74
# CNS
Why do infants have open fontanels and flexible cranial bones?
account for rapid brain growth w/o ↑ the ICP
75
# CNS
What are the 2 major fontanels & when do they close?
Anterior: ~ 2yrs of age
Posterior: ~4 mos of age
76
# CNS
Why are the fontanels considered an extra v/s?
* assess ICP
* assess for dehydration (sunken fontanels)
77
# CNS
Why is hypoglycemia poorly tolerated in infants?
* ↑ cerebral metabolic requirements
* glucose main food for brain
78
# CNS
Are CBF & CBF autoregulation fully developed in neonates?
No
* CBF regualtion is present (may not be fully developed)
* CBF not fully developed
79
# CNS
Why are neonates more prone to intracerebral hemorrhage?
1. CBF not fully developed
2. cerebral vessels more fragile
80
# CNS
What are the 5 Hs that can precipitate intracranial/intraventricular hemorrhage in neonates?
1. Hypoxemia
2. Hypercarbia
3. Hyper/Hypo glycemia
4. Hypernatremia
5. HTN/HoTN
81
# Renal System
Nephrons are matured up to what week gestation?
35 weeks - lower GFR
82
# Renal System
When does GFR reach adult levels?
6-12mos old
83
# Renal System
What is the GFR of a premature infant?
0.55mL/kg/min
84
# Renal System
What is the GFR of a full term infant?
1.6mL/kg/min
85
# Renal System
What is the GFR of a 2 yr old?
2mL/kg/min
86
What are 2 reasons why infants don't tolerate fluid overload?
1. stiff myocardium that does not respond to fluid well
2. low GFR
87
# Renal System
Why are infants @ increased risk of hyponatremia?
1. diminished ADH - immature renal medulla
2. **Na Excreters**
3. unable to conserve Na
4. RAAs reduced → Na lost from distal tubules
88
# Renal System
Why do neonates have decreased ability to reabsorb glucose?
What type of diuresis can develop when we replace glucose?
immature renal tubules
Osmotic diuresis = fluid shift issues
89
# Renal System
How much fluid do neonates require per day?
150mL/kg/day
90
# Hepatic System
When do glycogen stores reach adult levels?
~3 weeks old
91
# Hepatic System
Why are neonates high risk for hypoglycemia from 48hrs - 3 weeks old?
90% of glucose stores are released in 1st 48hrs
* return to normal @ 3 weeks old
92
# Hepatic System
What effects does low albumin and alpha-1 acid glycoprotein have?
* Albumin binds acidic drugs
* Alpha-1 Acid Glycoprotein binds basic drugs
* **more free floating drugs in neonate - toxicity**
93
# Hepatic System
When do clotting factors reach adult levels?
* ~ 1 week old
| *low initially*
94
# Hepatic System
What is a medication neonates get @ birth to prevent bleeding?
1 mg Vit. K
| *parents can refuse* = **risk of bleeding & intracranial hemorrhage**
95
# Hepatic System
What are the Vit. K dependent factors?
II, VII, IX, X
96
# GI System
T/F - Gastric pH is acidotic @ birth.
False
* alkalotic - decreases to normal by day 2
97
# GI System
What s/s are present w/ upper intestinal anomalies?
vomiting/regurgitating
98
# GI System
What s/s are present w/ lower intestinal anomalies?
* abdominal distention
* failure to pass meconium in 1st few days of life
99
# GI System
When does coordinating swallowing w/ respiration mature?
4-5mos of age
100
# GI System
What is the most common timing for GI developmental problems to display sxms?
1st 24-36hrs of life
101
# Thermoregulation
What are the 3 reasons why thermoregulation is difficult?
1. large body SA
2. lack of subQ tissue
3. Inability to shiver
102
# Thermoregulation
Neonates use NST.. what is this and how does it work?
What 3 negative things can NST lead to?
* non-shivering thermogenesis
* hypothermia = NE release SNS stimulation = enhanced metabolism of brown fat = heat production
* **metabolic acidosis, bradycardia, cardiac collapse**
103
# Thermoregulation
What 3 things can hypothermia lead to?
1. bradycardia
2. acidosis
3. coagulopathies
104
# Thermoregulation - heat loss
What type of heat loss occurs through vaporization of liquid from body cavities & respiratory tract?
Sensible:
Insensible:
* Evaporative
* Sensible: sweating
* Insensible: through skin
105
# Thermoregulation - heat loss
How can we prevent insensible heat loss?
* remove wet clothing
* keep pt dry
* plastic barriers (bair hugger)
* decrease humidity in room
* **humidifier on circuit**
106
# Thermoregulation - heat loss
What type of heat loss is responsible for the majority of anesthetic heat loss?
Prevention?
Radiant - heat is transferred to the environment (equilibration)
| Prevention: wrap baby, prevent heat from transferring around baby
107
# Thermoregulation - heat loss
What type of heat loss is due to direct contact?
Prevention?
Conductive
| Prevention: under body bair hugger, hydrowarmer, warm irrigation fluid
108
# Thermoregulation - heat loss
What type of heat loss is precipitated by air movement (flow of air around baby)?
Prevention?
Convective
| Prevention: increase OR temp
