Pediatrics Flashcards
Definitions of neonate, infant, and child
Neonate: Birth to 30 days
Infant: 1 month to 1 year
Child: 1 - 12 years
Kids develop similar physiology to an adult by age
8 years
Premature is considered
37
Fetal transition to neonatal physiology takes place during the first ___-___ hours
24-72
Ductus arteriosus closure
Anatomic closure: 2-6 weeks
High O2 can help it close
Foramen ovale closure
Functionally: rapid closure
Anatomically: 3 months
CV differences in kids
Noncompliant LV
- limited ability to handle increase in fluid volume
- Unable to increase SV, only able to increase CO by increasing HR (this means that BP depends on HR as well)
Limited catecholamine stores
- May give atropine prophylactically
- Effect of ephedrine?
Fetal circulation considerations
- Cold, hypoxia, and hypercarbia can re-open these shunts
Higher metabolic O2 demand than adults (because they are growing so rapidly!)
Pulmonary differences in kids
Increased O2 consumption
TV and dead space same as adults (dependent on rate for adequate MV for needed O2 demand)
Resp rate is 2-3x that of adults
Increased chest wall compliance
Decreased lung compliance**
SMALL DIAMETER AIRWAYS (increased resistance to flow)
Hypoxia and hypercapnea will depress ventilation (compounds the problem!)
Decreased Type 1 muscle fibers in diaphram (kid poops out quickly from high RR and poor lung compliance)
Fewer alveoli
Smaller FRC**
Unique airway differences in kids
Narrow nasal passages (lean towards using oral airway)
Obligate nasal breathing** (until about 6 months, until then, make sure their nose is clear so they can breath!!!)
Cricoid cartilage is most narrow portion of airway
Short neck, large head, large tongue
Larynx is more cephalad (C4) and is funnel shaped
Epiglottis is narrow and stubby
VC attachment is angled anterior and caudad
Smaller margin of error for R mainstem intubation
How should infants be positioned for intubation?
Towel roll under shoulders b/c their heads are fucking huge. This should align things properly
Also, neck should be neutral or slightly flexed.
Extreme flexion or extension will kink airway***
Just 1mm of airway edema can decrease cross-sectional area by ___%
75%
Fluid/Electrolyte differences in kids
Higher total body water
ECF = 40% of TBW in neonates and 20% of TBW in those over 2 years
More ECF = more prone to dehydration
Kidney function reaches normal by __ months
6 months
Until this time, every week counts for kidney development!!
Hemoglobin levels in kids
Hgb at birth = 18-20g/dL - Most of this here is fetal Hgb and has a shift to the left! This helps to extract O2 from the mother. Low Hgb levels bad in newborn d/t shift to the left. Hgb pre-term = 13-15 g/dL Hgb at 2 months = 10-12 g/dL - Lower threshold for transfusion Hgb at 6-24 months = 12 g/dL Hgb at 2-6 years = 12.5 g/dL Hgb at 6-12 years = 13.5 g/dL
In newborn blood loss >10-15% may not be tolerated Fetal Hgb
Most kids though end up doing ok with low hgb. Always check with surgeon before giving blood to a kid.
Hepatic and GI differences in kids
Low hepatic blood flow in first months of life
CYP450 maturity has huge variability
Type 1 reactions mature faster than Type 2 (conjugation) –> so avoid drugs that undergo type 2
Low glycogen stores (worry about hypoglycemia!)
Impaired conjugation –> jaundice
Poor coordination with breathing and swallowing until 4-5 months (reflux is common!)
Low plasma albumin levels
Kids can’t shiver until __ months
3
Until then, they rely on brown fat metabolism
Keeping kids warm is a huge priority**
Thermoregulation
Brown fat metabolism = high O2 consumption
Thin skin
Low fat content
Large surface area
Interventions: Warmed mattress, blankets, warm room, cover the head, humidify inspired gases, bair hugger
General rules about kids and E1/2t of drugs
Infants: Prolonged E1/2t
Children 2-12: Shortened E1/2t
Reaching adulthood: Normal E1/2t
Highes to lowest MAC requirements
Infant (highest)
Neonate
Child
Adult (lowest)
Preemies tolerate IAs poorly. Use minimally or not at all.
When is it appropriate to give sux to a kid?
RSI and laryngospasm
Must give with atropine!
Avoid second dose if possible (higher risk of bradycardia and arrest with second dose)
Roc can be risky b/c it has a longer DOA if you have difficulty securing the airway (peds have lower FRC and higher O2 demand –> desat quickly)
NDMR dosing is kids
Kids have a higher Vd, but also immature NMJ. This results in NDMR dosing similar to adults.
Neostigmine dosing is slightly lower though (.02-.05mg/kg)
NMJ matures around 2 months.
Why is adequate reversal critical in kids?
Lower FRC and higher O2 demand (need proper lung functioning)
Increased lung compliance
MV dependent on RR
How to determine if tube is the correct size in a kid
Check leak pressure
If leak occurs at
Reservoir bag size for peds
1-2L
MONITOR YOU MUST HAVE FOR PEDIATRIC CASES
Precordial Stethoscope!!!
Very sensitive to bronchospasm. Some places will send you home if you forget it at clinicals.
Pediatric ETT insertion depth
2cm below cords
Often there will be black mark 2cm proximal to ETT tip. Place black mark at the cords for correct placement.
If cuffed ETT is used, cuff pressure should be kept below _____mmHg
25mmHg
Laryngoscope blade sizes
Miller 0 neonates - 2 years
Miller 1 2 - 6 years
Miller 2 > 6 years
Mac 1 2 - 6 years
Mac 2 >6 years
Miller is more popular in peds
Formula for ETT insertion distance beyond 2 years
After age of 2, can be calculated as:
(Age/2) + 12
Formula for ETT size above 2 years
(Age + 16) / 4
LMA sizing
1 = up to 5 kg, cuff 4-6cc 1.5 = 5-10 kg, cuff 7-10 cc 2 =10-20 kg, cuff 10-15 cc 2.5 =20-30 kg, cuff 14-20cc 3 = 30-50 kg, cuff 20-30cc 4 = 50-70kg, cuff 30-45 cc
Pro-tips for pediatric airway management
Pillow under shoulders / occiput for neutral alignment
Keep fingers off soft tissue during mask ventilation!!
For all equipment, have one size larger and smaller than anticipated available
Oral airways preferred to nasal (they have smaller nasal passages)
Air leak should be present after intubation between __-__mmHg of pressure
20-30mmHg
EBV for kids
Preemie (90-100mL/kg)
Neonate (80-90mL/kg)
Infant (75-80mL/kg)
Child > 6 (70mL/kg)
Hct in young kids
Hct of 55% in neonates (but mostly HgbF)
Falls to 30% as it switches to HgbA.
Settles to 35% by about 6 months.
Formula for volume of PRBCs to transfuse
EBV x desired Hct x (current Hct / Hct of PRBCs)
Formula for dosing of platelets
.1-.3 units/kg
Fluids to use in kids
D5W for maintenance (b/c risk of hypoglycemia)
LR for replacement of deficits and losses
Delivering fluid in kids
2 years, use 500cc bag with microdrip
Kids are easily fluid overloaded.
Have med port as close to the pt as possible
Small air bubbles can be huge deal (as little as .1cc can occlude an extremity)
URI in kids can result in increased airway irritability for up to ___ weeks
6 weeks
Kids and premedication
9 months = probs need it
Role of parents is huge. They can come to the OR for induction.
Pediatric Induction Sequence
Place monitors Mask with 70% N2O and 30% O2 Add sevo (overpressure) until LOC occurs Have assistance start an IV Turn off N2O to give 100% O2 with sevo (pre-oxygenation). They should be breathing on their own.
Once pre-oxygenation is done and IV is placed, give MNB.
Once paralyzed, turn off agent and intubate.
Start maintenance.
What is the true MAC of the patient?
Expired agent concentration.
NOT what you set the vaporizer to.
Post-op delirium is common with these agents
Sevoflurane and desflurane.
Ketamine
Kids post-op will scream, be confused, and look like theyr’e in pain, but they will snap out of it.
Sometimes versed pre-op can help with this.
Can look concerning, but it’s just something that happens in kids. Let parents know this.
Laryngospasm is more/less common in kids than adults. Also tx.
More common. Anticipate that kids will have a laryngospasm.
Treat with PPV and .5-1mg/kg sux
Treatment of post-intubation croup (inflammation around the vocal cords)
Decadron .25-.5mg/kg
Racemic epinephrine
Caudal block
Epidural block for kids 7.
Short beveled needle 2-3cm into sacral canal. Dosing: High sacral block: .5mL/kg High lumbar block: 1mL/kg Mid thoracic block: 1.25mL/kg Max volume of 20mL***
Considerations for preemies:
Preemie = >37 weeks
Lack of surfactant can lead to IRDS
Increased WOB
Risk for post-op apnea and bradycardia
Minimal glycogen stores (hypoglycemia and acidosis risk)
Unable to handle large loads of protein (would fluid overload the kid who has non-compliant heart)
Renal function;
- Decreased GFR
- Impaired sodium retention
- Impaired glucose excretion
- Impaired bicarb reabsorption
- Difficult to dilute
- Do frequent electrolyte checks and be careful with fluid administration
Higher total body water % (think about H2O soluble drugs)
Less body fat (less drug distributed into fat)
Prolonged E1/2t (immature liver and kidneys)
Lower anesthetic requirement (immature BBB and more sensitive to opioids)
Risk for reverting to fetal circulation**** Because the shunts were meant to be open at that age.
Considerations for trisomy 21
Airway:
- Short neck
- Irregular dentition
- A-O instability (do radiographic eval)
- Large protruding tongue (difficult to ventilate)
- Subglottic stenosis (very narrow cricoid)
Many have congenital cardiac abnormalities
