Test 4: Pediatric Anesthesia Pt. 1 & 2 Flashcards
(116 cards)
1
Q
Pediatric Pt population ages
A
- Neonates: birth -1month
- Infants: 1 month - 12 months
- Toddlers: 12 months - 3 years
- Preschool: 4 - 6 years
- School age: 6-13 years
- Adolescents: 13-18 years
2
Q
At approximately ____ years old, the physiology and anatomy of the child is mostly like the adult pt
A
approximately 8 years old
3
Q
What are the weights for LBW, VLBW, ELBW and micropremie
A
- LBW: <2500 grams
- VLBW: <1500 grams
- ELBW: <1000 grams
- micropremie: <750 grams
4
Q
- Myocardial structure of the neonatal heart is ____ developed compared to the adult
- Neonatal CO is ____ dependent
- ____ is vital for myocardial performance
- The neonate has a poorly developed ____ reflex, and the autonomic innervation is predominately ____
A
- Myocardial structure of the neonatal heart is less developed compared to the adult
- Neonatal CO is HR dependent
- Calcium (largely dependent on free Ca++) is vital for myocardial performance
- The neonate has a poorly developed baroreceptor reflex, and the autonomic innervation is predominately Parasympathetic
5
Q
Normal HR, SBP and DBP of neonate
A
HR: 140-160 bpm
SBP: 70-75
DBP: 40
BP will be even lower with preterm infants
6
Q
Down and dirty way to estimate what you want a preterm MAP to be (once they are born)
A
take their gestational age
i.e. they are 25 weeks old, their MAP should be around 25
7
Q
Normal HR, SBP and DBP of 12 mo
A
- HR: 120
- SBP: 95
- DBP: 65
8
Q
Down and dirty way to determine what SBP should be for childern
A
70 + (2 x age in years)
9
Q
Normal HR, SBP and DBP of 3yo
A
- HR: 100
- SBP: 100
- DBP: 70
10
Q
Normal HR, SBP and DBP of 12 yo
A
- HR: 80
- SBP: 110
- DBP: 60
11
Q
Normal Hgb value at birth
A
18 - 20 g/dL
- neonates have predominately FHgb
- FHbg has a lower P50
- FHgb creates a left shift in the hgb dissociation curve
12
Q
At 3-4 months, what happens to the child’s hgb?
A
-
physiological anemia
- d/t decrease in erythropoietin and a decrease in RBC production
- RBC die and there is less being made
13
Q
EBV for a premie
A
90 - 100 mL/kg
14
Q
EBV for newborn (<1 mo)
A
80 - 90 mL/kg
15
Q
EBV for infant (1mo - 3yo)
A
75 - 80 mL/kg
16
Q
EBV for child (>6yo)
A
65 - 70 mL/kg
17
Q
Select 2: select the statement that most accurately reflects the CV system of the newborn
- HR is the primary determinant of BP
- phenylephrine is the first-line treatment for HoTN
- stress is more likely to activate the PNS
- HoTN is defined as SBP <70 mmHg
A
- HR is the primary determinant of BP
- Stress is more likely to activate the PNS
phenylephrine is NOT the first line: it will decrease the HR,
- the heart is very dependent on Ca++ (so you can give calcium gluconate if the issue seems to be a inotrope issue)
18
Q
Neonatal Respiratory system:
- Alveolar ductal development starts at ____ weeks gestation
- neonatal alveolar surface area is ____ of the adult
- surfactant production and secretion begins at ____ - ____ weeks gestation
A
- Alveolar ductal development starts at 24 weeks gestation
- neonatal alveolar surface area is ~1/3 of the adult
- surfactant production and secretion begins at 22-26 weeks gestation
- type II pneumocytes
19
Q
Peak of surfactant production is at ____ weeks - anytime before that, we are worried about what?
A
35-36 weeks
- anytime before that, the infant is prone to risk of respiratory distress syndrome because of the dramatic increase in surface tension
20
Q
While we would love all babies gestational age to be 37-42 weeks, with tight medical support, a baby can be delivered at ____ and still be viable
A
22-26 weeks
- 24 weeks is the beginning of lung/alveoli development, so <24 weeks is hard to keep them alive
21
Q
Breathing mechanics of the neonate
A
- pliable chest wall
- horizontal ribs - provide lots of structural assistance paradoxical breathing is normal
- diaphragm is flat (less dome shaped)
- less type 1 muscle fibers (slow twich fibers that are fatigue resistant) they fatigue faster -> respiratory distress
22
Q
- Neonate respiratory system also has ____ metabolic rate and O2 consumption by ____ of the adult
- the minute ventilation is more dependent on ____ instead of ____
- we see a decreased ____ with immature respiratory control
A
- Neonate respiratory system also has increased metabolic rate and O2 consumption by 2x of the adult
- the minute ventilation is more dependent on respiratory rate instead of tidal volume (they have a fixed TV which is 6-8 mL/kg)
- we see a decreased FRC with immature respiratory control
- worse with general anesthesia - much less reserve
- desat fast, and desat even faster the second time you try to intubate
23
Q
Pediatric respiratory anatomy
A
- lots of risk for obstruction
- Large tongue
- superior larynx
- not anterior, but just higher up at C3-C4 vertabrae, instead of C4-C5 in adults
- visulaization is more challenging
- omega-shaped epiglottis
- Mac blade doesnt make the epiglottis pop-up or control as well
- vocal cords are angled
- short funnel-shaped trachea
- narrowest portion is the cricoid cartilage
24
Q
Why can we use uncuffed ETTs for pediatric pts?
A
Because of the funnel shaped narrowoing of the trachea past the cords (cricoid ring is the narrowest part)
25
Bronchus anatomy in peds
- Right and Left mainstem bronchi will take off at a 55 degree angle from the trachea
- obligate nasal breathers until about 5 months old
- so they can breathe and feed at the same time
- large occiput and short neck
26
What does the Large occiput and short neck change with our intubation?
- Large occiput lying flat will cause flexion and lead to obstruction
- also difficult view
- align axis with a modified sniffing position
27
Poiseuille's Law for infants
- Trachea is much more narrow - so remember, the radius is the most important factor affecting the flow (**its to the power of 4**)
- any small amount of edema can have a huge impact on increasing airway resistance
28
If the radius of the tube is halved, how much does resistance increase?
Resistance is increased 16-fold (Poiseuille's law)
29
Which statement most accurately describes the infant's airway? (select 3)
- Larynx is positioned more cephalad
- vocal cord posiiton at C1-C2
- C shaped epigottis
- epiglottis is broad
- Right and Left mainstem bronchi take off at the same angle
- vocal cords have anterior slant
- larynx is more cephalad
- R and L bronchus take off at the same angle
- vocal cords have an anterior slant
30
Infant CNS
- ____ myelination of nerves
- ____ NMJ
- Most neurological growh and development occurs ____
- rapid ____ occurs after birth
- ____ is immature until 1yo
- **incomplete** myelination of nerves
- not complete until 3yo
- **immature** NMJ
- Most neurological growth and development occurs **in utero**
- rapid **brain growth** occurs after birth
- **BBB** is immature until 1yo
31
What should we know about the immature NMJ in infants?
- first 2months, NMJ change
- prolonged channel opening
- immature muscles depolarize easier
- greater affinity for NDNMB (varying responses from drugs)
32
Conus medullaris terminates where in an infant?
Spinal cord ends where at age 8?
Where does the dural sac end until 6 years?
- Conus medullaris in infants: L2-L3
- Spinal cord: L1 at age 8
- Dural sac: S2-S3 until about 6 years old
33
When does the posterior fontenelle close?
about 4 months
34
When does the anterior fontanelle close?
2 years old
35
What things can fontanelles tell you about your pt?
- increased ICP: fontanelles will bulge
- dehydration: sunken in
36
What does an immature BBB have to do with us?
- BBB is immature until 1yo: **lots of drugs can penetrate BBB that wouldn't normally do so in an adult**
- primary food for the brain is glucose - infants don't tolerate hypoglycemia well (dextrose containing fluids used lots)
37
Is autoregulation of the brain present in infants?
- yes, but immature
- but CBF isnt developed much so higher risk for intracerebral hemmorhage
- vessles are much more delacate especially in preterm and LBW babies
38
Renal system
- nephrons are still being formed up to ____ weeks gestation
- GFR reaches adult level by ____ months
- ADH is ____
- immature ____
- nephrons are still being formed up to **35** weeks gestation
- GFR reaches adult level by **6-12** months
- premature: 0.55 mL/kg/min
- full term 1.6 mL/kg/min
- 2yo: 2 mL/kg/min
- ADH is **dimished**
- immature renal medulla
- immature **renal tubules**
- obligate sodium excretors
- reduced RAAS system
## Footnote
excrete sodium, so may need to replace sodium and glucose in surgery
39
With the immature kidneys, what should we be aware of when giving drugs?
We can have prolonged half-lifes of our medications
40
Neonates require ____ mls/kg/day of fluid
150 ml/kg of fluid
- lots of insensable losses mostly from evaporation b/c of higher surface area to body weight ratio (4x as an adult)
- but they don't tolerate over hydration either
41
Hepatic System
- glycogen stores do not reach adult levels until ____ weeks
- low ____ and ____
- ____bilirubinemia
- ____ levels of clotting factors
- require ____ to prevent bleeding
- glycogen stores do not reach adult levels until **3** weeks
- extreme risk of hypoglycemia
- low **albumin and AAG**
- **hyper**bilirubinemia
- only at 75-80% of adult
- more free floating drugs in neonate
- **low** levels of clotting factors
- require **Vit K** to prevent bleeding
42
Infants are usually given 1 mg of ____ at birth why?
- Vitamin K (required for factors II, VIII, IX and X)
- without administration, neonate is predisposed to bleeding and intracranial hemmorhage
43
GI system in neonates
- gastric pH is ____ at birth and goes back to normal by day ____
- coordination of ____ and ____ does not fully mature until ____ months
- if there are developmental problems, s/s will occur within ____ hours
- rate of absorption of PO drugs is ____ because of ____
- gastric pH is **alkalotic** at birth and goes back to normal by day **2**
- coordination of **swallowing with respiration** does not fully mature until **4-5** months
- if there are developmental problems, s/s will occur within **24-36** hours
- upper intestinal issues = vomiting or regurgitation
- lower intestinal anomalies = abd distantion or failure to pass meconium
- increased risk for GERD
- rate of absorption of PO drugs is **slower** because of **delayed gastric emptying**
44
Thermoregulation
Why do infants have an inability to regulate body temp?
- Large body surface area
- lack of subQ tissue
- inability to shiver
45
Since babies can't shiver, what do they use instead?
Non-shivering thermogenesis (NST)
- stimulated by SNS to enhance the metabolism of brown fat which increases heat production
46
How does brown fat metabolism increase heat production?
- Hypothermia stimulates Norepi to be released
- With brown fat metabolism, lipase is released that splits triglyceride into glycerol and fatty acids, which increases heat production
- however, this will also lead to a **metabolic acidosis** with its byproducts (leading to bradycardia and cardiac collapse)
## Footnote
VAAs also interfere for thermoregulation
47
Heat is exchanged between the body and its environment in both directions, by what 4 mechanisms?
Of the 4 mechanism, what is the most important factor to heat loss in the OR?
* Conduction
* Convection
* **Radiation (most important factor to heat loss in the OR)**
* Evaporation
48
Heat loss d/t the heat of vaporization taking place at the skin and lungs.
Evaporation
49
What are ways to mitigate heat loss through evaporation for pediatric patients?
* Using a heat and moisture exchanger (HME)
* Heated humidifier (Concha-therm)
* take off wet clothes
* Fluid warmers
* Knowledgeable provider
50
Heat loss d/t infrared radiation being emitted from the body to cooler objects in the environment.
* Radiation
* Radiation is the most important factor to heat loss.
| no direct contact (air between the pt)
51
What are ways to mitigate heat loss through radiation for pediatric patients?
* Warm the room
* Use radiant heat lamps
* Body coverings
* Aluminized plastic coverings
52
Heat loss d/t the body contacting a cold object.
Conduction
53
What are ways to mitigate heat loss through conduction for pediatric patients?
* Warm the OR and the OR bed
* Use warming blanket
* Warm fluids (long cases)
* Warm irrigation fluids
* Bair hugger
54
Heat loss d/t air movement around the body
Convection
55
What are ways to mitigate heat loss through convection for pediatric patients?
* Warm the rooms
* Close the doors
* Head covers (thermal insulation)
* Bair hugger
* Body covering
| want warm air going by
56
Temp for room for peds
75 - 80º F
57
What are potential problems that can occur if a child becomes too cold in the OR?
* Decreased metabolism will affect rate of drug distribution, slow to wake.
* Blood coagulation is slowed with hypothermia
* Shivering in the PACU (may cause bleeding with tonsillectomies)
* Peripheral vasoconstriction (harder to start an IV)
* Cardiac arrhythmias
58
What percentage of total body heat loss is due to evaporation?
20%
59
Spontaneous ventilation normally is ____ºC at the pharynx with humidity of ____%.
Spontaneous ventilation normally is **32ºC** at the pharynx with humidity of **86%**
60
A 2 week old neonate will be expected to demonatrated the following except for:
- increased free fraction of highly protein-bound drugs
- faster circulation time
- larger volume of distribution for water-soluble drugs
- shorter duration of action of lipid-soluble drugs
- shorter duration of lipid-soluble drugs
61
Pharmacokinetics with infants
- absorption and distribution are ____ (higher ____)
- decreased ____: d/t immature ____ pathways and ____
- underdeveloped ____ pathway
- immature ____
- absorption and distribution are **increased** (higher **CO**)
- neonate CO: 400 mL/kg/min
- infant CO: 200 mL/kg/min
- adolescent CO: 100 mL/kg/min
- decreased **elimination**: d/t immature **metabolic** pathways and **kidneys**
- underdeveloped **CYP450** pathway
- immature **BBB**
- local anesthetics can cross and potentially cause seizures
62
Body composition
- infants have ____ TBW, ____ ECF compartment, ____ ICF
- ____ Vd for water soluble drugs
- ____ drugs have a longer effect
- ____ free concentration of protein-bound drugs
- infants have **greater** TBW, **larger** ECF compartment, **decreased** ICF
- **larger** Vd for water soluble drugs
- less redosing though becasue immature ACH receptors
- **lipid-soluble** drugs have a longer effect
- **higher** free concentration of protein-bound drugs
63
Pharmacodynamics receptor function differences: N-ACH-R
- fetal N-ACH receptors: remain open longer and may be more resistnat to NMBD
- ACH released is less than adult though causing sensativity of NDNMBD
*yes its confusing - this just leads to an unpredictable response of NMBD*
64
Pharmacodynamics receptor function differences: Opioid receptors
- changes in number and affinity for Mu and Kappa receptors (resp depression receptors) may account for increased resp depression
65
Pharmacodynamics receptor function differences: GABA
- 1/3 of quantity of adults
- half of the receptors have a high affinity for benzo binding or other anesthetics
- this could explain why our MAC is low for neonates, but increases at about a month old
66
Inhalation agents
- ____ equilibrium
- MAC is ____ for neonates, but ____ for infants
- more ____ side effects
- ____ shunting
- **rapid** equilibrium
- MAC is **less** for neonates, but **increased** for infants
- more **CV** side effects
- **left to right** shunting is more common
- left to right shunt is minimal increase in uptake
- if theres a right to left shunt, theres a decrease in uptake
67
When does MAC peak?
2-3 months old
(but sevo peaks at about 0-6 months)
68
Why does sevo have a sooner MAC peak?
Sevo has a lower blood solubility which makes the inhalation induction rapid
69
MAC of N2O in adults is 104%, what is the MAC in childern?
Trick question, MAC of N2O in peds has not been determined (ususally start at 20-30% for induction)
70
Why is the blood:gas equilibrium reached much faster than adults?
Trick question: Although Infants and children have greater CO, the increased
- greater minute ventilation
- high ratio of TV:FRC
- and low subQ fat
will redistribute and therefore go to the vital organs more often
## Footnote
Nagelhout: Infants and children have a higher cardiac output per weight than adults. As noted previously, the higher the cardiac output, the slower the onset. This effect is minimized, however, by the increased cardiac output distributed to the vessel-rich group in children. The infant’s lower muscle mass allows more of the agent to concentrate in the vital organs. This overall effect is to promote uptake to the brain.
71
What is the pediatric induction dose of IV Propofol?
What is the infusion dose?
* Propofol IV: 2-3 mg/kg
* Propofol infusion: 50-200 mcg/kg/min
## Footnote
Associated with HoTN because the dose is so profoundly larger
72
Induction dose for ketamine in peds?
1-3 mg/kg
Doesn't really cause CV or resp depression, good for unstable peds
73
Etomidate peds dosing
0.2 - 0.3 mg/kg
not used much in peds
- larger Vd
74
Dexmedetomidine peds dosing
- minimal resp depression
- used for procedural sedation
- 1-2 mcg/kg (intranasal takes 30 min for peak)
- decreases emergence delirium
- but high doses prolong the recovery phase
## Footnote
Mimics natural sleep
75
Peds Morphine dose
0.05 -0.1 mg/kg
- careful with resp depression (neonates are more sensative)
- histamine release
76
Peds Codeine considerations
"morphine-like" drug - ~10% as potent
- some resp depression
- 90% bioavailability
- unpredicable metabolism
- **black box warning** peds after tonsillectomy
77
Peds considerations for fentanyl
- good hemodynamic stability and rapid onset
- large Vd in neonates
- clearance is reduced in preterm
0.5-2 mcg/kg
bolus could be 3 mcg/kg
78
Peds considerations for remifentanyl
- differences in the half life are minimal
- neonates clear more rapidly than older children (larger Vd, equilalant half-life)
- bolus required
79
Considerations for NMBDs
- Increased sensativity
- Increased Vd
- reduced clearance, immature NMJ
- NMBDs are highly ionized
## Footnote
More sensative to non-depolarizing drugs, equally as sensative to sux
80
What is the pediatric dose of IV Succinylcholine?
What is the pediatric dose of IM Succinylcholine?
- IV:
- infants: 2mg/kg
- children: 1mg/kg
* IM:
- Neonates: 5 mg/kg
- 6 months: 4mg/kg
*Can have a prolonged duration d/t decreased plasma cholinasterase (6-10min)*
*Brady can occur! always give glyco or atropine along with sux*
81
Reversal of NMBD in peds
- difficult to assess
- Anticholinasterase drugs used for reversal:
- Neostigmine: 0.05 - 0.07 mg/kg
- Edrophonium: 0.5 - 1 mg/kg
- Sugammadex is not approved for children <2yo
## Footnote
But Dr. Mot has given to all ages
82
# End part 1
Anesthetic considerations for the administration of NMBD in the neonate include:
- avoidance of sux
- a longer duration of action of sux
- a larger dose of sux
- a larger dose fo NDNMBD
Larger dose of sux
83
# Begin part 2
What is the pediatric dose of IV Atropine?
What is the pediatric dose of IM Atropine?
* Atropine IV: 0.01 mg/kg
* Atropine IM: 0.02 mg/kg
84
Three most common asked about syndromes that clue you for a potential difficult airway
1. Trisomy 21 (Down syndrome): extra tissue, large tongue, mindful of alantooccipital abnormalities
2. Treacher Collins: mircognathia, small cord opening, zygomatic hypoplasia
3. Pierre-Robin: micrognathia, glossoptosis, cleft palate, cervical dysfunction
## Footnote
Basically a kid with a "syndrome" be prepared with a video scope in the room
85
What is the pediatric IV dose of lidocaine?
* Lidocaine IV: 1 mg/kg
86
Pediatric flow chart for case cancelation
87
Factors that contribute to pediatric anxiety?
* 1-5 years-olds
* Shy/sensitive type
* High IQ/ Lack good adaptive ability
* Previous surgeries
* Parental anxiety
88
How many hours must a patient be NPO if they consume clear liquids?
2 hours
89
How many hours must a patient be NPO if they consume breast milk?
4 hours
90
How many hours must a patient be NPO if they consume infant formula?
6 hours
91
How many hours must a patient be NPO if they consume non-human milk (cow milk)?
6 hours
92
How many hours must a patient be NPO if they consume a light meal?
6 hours
93
How many hours must a patient be NPO if they consume a meal with fat?
8 hours
94
What is the most common anesthesia delivery system?
What are the benefits of this system?
Circle System
* light weight
* can use LOW gas flows
* resistance in valves and CO2 absorber
95
What is the ET-Tube size formula for pediatric patients older than two years?
(Age + 16)/ 4
then subtract .5 to get the cuffed size tube you want
96
What is the formula for determining what depth the tube (cm) should be taped at?
(Age/2) + 12
97
ET Tube Size for Preemie 1 kg and under
2.5
98
ET Tube Size for Preemie 1-2.5 kg
3.0
99
ET Tube Size for term neonate to 6 months
3.0-3.5
100
ET Tube Size for 6 months to 1 year
3.5-4.0
101
ET Tube Size for 1-2 years
4.0-4.5
102
Emergency med doses of:
- Epi
- Sux
- Atropine
- Glyco
- Epi: 0.01 mg/kg
- Sux: 2mg/kg IV, 4mg/kg IM
- Atropine: 0.02 mg/kg
- Glyco: 0.01 mg/kg
103
List the monitoring equipment needed for a pediatric patient.
* 3 lead EKG
* masks
* Precordial stethoscope
* Two pulse oximeters (upper and lower extremities)
* Temp probe (Axillary)
* BP Cuff
* FiO2, ETCO2, and Agent monitors
104
Premedication doses
- Midazolam
- Dexmedetomidine
- Ketamine
- Midaz: 0.25 - 1 mg/kg PO (most people do 0.5 mg/kg)
- Dex: 1-2 mcg/kg intranasal
- Ketamine: 5-10 mg/kg IM
105
When would you choose a IV induction over an inhalation induction?
Biggest reason is if you have to do an RSI (full stomach, trauma, known difficut airway)
## Footnote
sometimes you have have a difficult intubation, but not a difficult mask - so you can still mask induce
106
Main way to open the peds airway?
Posisitoning!
- their huge head will flex their airway and cause obstruction
- use shoulder roll or small pillow to extend head, or go to lateral decub.
107
Maintance fluids calculations
4-2-1 rule
4 ml/kg for first 10kg
2 ml/kg for next 10kg
1ml/kg for any additional weight above 20kg
## Footnote
denver health just does 20-30ml/kg across the board for peds
108
Equation for how much blood to give a ped
Volume of PRBCs = (desired HCT - Current HCT) x (EBV/HCT of PRBCs)
normal HCT of PRBCs is ~60%
4mls/kg of PRBCs will raise the Hgb by 1g/dL
109
Big contraindication for Outpt peds
infants born premature <35 weeks or those <60 weeks of post-conceptual age
- big risk for postop apnea
110
Typical risk factors for emergence delirium
- ages: 2-9
- surgery type (ENT are associated more)
- anesthetic (gas highest risk factor)
- pre-exiting Emergence delirium
- anxiety or parental anxiety
- pain
111
Treatment for emergence delirium
treament pain
alpha 2 agonist
propofol
time
112
Kids are natural ____ breathers
Nasal
113
What level will the larynx be in a preterm infant?
C3
114
What level will the larynx be in a full-term infant?
C3-C4 interspace
115
What level will the larynx be in an adult?
C4-C5
116
Doses for caudal blocks
1.2 - 1.5 mL/kg provides anesthesia and analgesia to the T4-T6 dermatome
max concentraion - 2.5 mg/kg
can add epi (1:200,000), clonidine (1-2mcg/kg), or fentanyl
