PEDIATRIC ANESTHESIA Flashcards
Pediatric patients have_______Which ____Vd of _____medications
meaning required___________
• Neonates require even more, but are also_________
Increased total body water: • ↑Volume of distribution of water-soluble medications Larger initial dose more sensitive to effects
Less muscle/fat →
• Slow redistribution of the drug into muscle will
- longer clinical drugs effect
- increase duration of clinical effect (opioids, barbiturates)
Mean cerebral blood flow peaks
at 3-8 years
Proportionally
↓CBF in neonates
• Highly lipophilic drugs used for anesthetic induction
rapidly achieve equilibrium with brain tissue
• Reduced cerebral perfusion means that onset time after IV induction is_________
slower in neonates that in early childhood
Offset time is also delayed why?
because redistribution to the well perfused and deep, under perfused tissues is less
Offset time to reach brain then
back to body
Acidic drugs: (2) (BAD)
• Acidic drugs mainly bind to________
diazepam, barbiturates
-albumin
- Basic drugs: __________ and _________
- Basic drugs bind to
- Mainly bound to __________= ↓premies/infants, adult levels by 6 mo
amide local anesthetics, alfentanil
globulins, lipoproteins, and glycoproteins
α1-acid glycoprotein (AAG) =
MAC
minimum alveolar concentration
Plasma protein binding ↓in neonates = _____and____ why?
more free medication –>↑pharmacological effect
↓total protein + albumin
Significantly affects highly protein bound drugs
• Phenytoin, salicylate, bupivacaine, barbiturates, antibiotics, theophylline, diazepam
Minimum Alveolar Concentration (MAC)
- Highest at 6 months
* Higher in children compared to adults
Why MAC higher
May relate to
maturational changes in cerebral blood flow (CBF) γaminobutyric acid (GABA) class A receptor numbers
or developmental shifts in regulation of CHLORIDE transporters
Chloride ions
hyperpolarizes cells
“wash-in” aka “FA/FI” aka “induction” aka
GO TO SLEEP!
Determined by 6 factors: FA/FI –> IAF/CSA
- Inspired concentration
- Alveolar ventilation
- Functional residual capacity (you want ideallow)
- Cardiac output
- Solubility (ideal low)
- Alveolar to venous partial-pressure gradient (ideal high)
FA/FI means
Fractional alveolar to fractional inspired partial pressures
How much in alveoli from how much was given
What’s in alveoli is whats in the
BRAIN
FA/FI best if it’s
1
Factors 1-3 determine
delivery of anesthetic to lungs
Factors 4-6 determine
determine rate of removal (uptake) from lungs
Low FRC
Desaturation
From alveoli to ______Eventually because of pressure gradient difference
blood
Ratio of alveolar ventilation (Va)
to FRC is the primary determinant of delivery of inhaled anesthetics to lungs
• Affects more soluble agents greatly because they are easily stolen out of the lungs
Greater Va/FRC =
more rapid equilibration
memorize slide
8
About ____ to get to brain
12 minutes
BP every
3-5 minutes
Normally, rate of rise in FA/FI is
• Mostly affects more
inversely related to changes in CO
soluble agents
• Less anesthesia leeched from lungs in
↓CO states
Opposite in pediatrics is with CO
OPPOSITE in pediatrics
• ↑CO speeds up FA/FI
• More CO distributed to vessel-rich group (VRG)
• Brain, heart, kidney, splanchnic organs, endocrine glands
Partial pressures of anesthetics in the VRG equilibrate with those in the alveoli more rapidly in neonates than in
adults
Isoflurane
Does not go to brain as quickly
As you go up FA/FI
more insoluble
Anesthetic gases are less soluble in neonates in general due to (3)
- ↑water content
- ↓protein/lipid concentration
- Reduces time for equilibration
For older people, VA induction with mask if CO is lower than normal
they go to sleep faster
less anesthesia leeched from lungs
The opposite in pediatric, proportion of blood that gets to the brain is
WAY MORE THAN ADULT
SLEEP FASTER
Solubility for gas (VA) is
NOT GOOD
IT IS SLOW
- Wash-out follows
* Exact opposite of
exponential decay
wash-in curves
- Washout similar in
* More rapid in
children and adults
neonates and infants
Cardiovascular
• Both directly and indirectly depressed
Affect Directly CV by
- Ca2+ channel blockade, altering conduction system, dilating peripheral vasculature
- ↓ Ca2+ flux
AFFect Indirectly CV by
- Affecting balance of ANS and neurohumoral, renal, or reflex responses
- All inhalational anesthetics modestly depress systolic BP in children
Down syndrome patients have increased risk of
bradycardia during induction
Sevoflurane can cause
bradycardia during induction
Junctional rhythm
HR normally unaffected by desflurane unless inspired concentration↑ suddenly
• Attenuated by________ administration
opioid administration
VOLATILE ANESTHETICS: Isoflurane:
LPC
☺ Less myocardial depression than Halothane
☺ Preservation of heart rate
☺ CMRO2 reduction rate (brain requiring less O2)
It is a PULMONARY IRRITANT
DESFLURANE (NOT USE IN KIDS OR WITH MASK)
Desflurane (2) major (IC) think DIC
☺ Increased incidence of coughing, laryngospasm,
secretions
☺ Concern of hypertension and tachycardia from
sympathetic activation
CONTRAINDICATED FOR ASTHMA
DESFLURANE
VOLATILE ANESTHETICS: SEVOFLURANE (LCM)
Sevoflurane
☺ Less pungent than Isoflurane
☺ Concern of compound A (nephrotoxicity) (for rats
☺ Most suitable for induction
Sevo usually run at
2L/min
ONLY FDA approved for INHALATIONAL Induction
SEVOFLURANE
Underlying pulmonary conditions
Do not use desflurane
Remember: About MAC and neonates and premies
MAC for potent volatile anesthetics
is increased in neonates, but may be lower for
sicker neonates and premies
* MATHmust know Induction drugs:
Methohexital dose is ? Rectal dose is? when can you use it ?
Long acting vs short acting
Advantage of methohexital (1)
Methohexital 1-2 mg/kg IV ☺20-30 mg/kg per rectum(can be used when propofol not available)
• Short acting barbiturate
• Minimal CV effects
Side effects and Contraindications for METHOHEXITAL
BAEH
Contraindication to Methohexital?
☺ Side effects: burning hiccup apnea extrapyramidal syndrome ☺ Contraindication: temporal lobe epilepsy
Propofol
Causes CHLORIDE SHIFT
Made from
GABA agonist
• Made from 1% propofol, soybean oil, egg yolk
phosphatide (ovolecithin), glycerol,** EDTA (BURNS!),
NaOH (buffer)
Propofol dose until (6 years of age)
☺ 3 mg/kg i.v. (until 6 years of age)
Propofol pain on injection use what?
☺ Pain on injection - 0.2 mg/kg Lidocaine i.v
Ketamine dose ______IV, PR orally
1mg/kg IV
☺6-10 mg/kg PR, orally
Ketamine works on _____receptor
• N-methyl-D-aspartate (NMDA) receptor
• Duration of KETAMINE if single IV bolus =
5-8 minutes
Advantages of Ketamine
• No upper airway obstruction but can still cause
hypoventilation (high doses)
**Contraindications of KETAMINE (COIS)
Increased ICP
Open globe injury
Seizure hx (cerebral excitation)
Can’t be used for EEG
Ketamine leads to (salivation )
☺ Increased SALIVATION (laryngospasm!) → antisialagogue
KETAMINE will do what to IOP
Increase
Etomidate dose pediatric
0.2 - 0.3 mg/kg IV
ETOMIDATE has_______
propylene glycol ; so it burns on injection
ETOMIDATE children needs?
ADvantages?
Disadvantage?
Like propofol, children need higher bolus
• Cardiac stable, less apnea than propofol, quickly redistributes
• Burns on injection (propylene glycol)
Diazepam pediatric dose
☺ 0.1-0.3 mg/kg orally
***Diazepam half life
***80 hours
**Diazepam contraindicated
***infants less than 6 months
Only FDA benzo approved in neonates
Midazolam
Midazolam dose
IV, intranasal, IM, oral , rectal
☺ 0.1mg/kg IV ( ☺ 0.2 mg/kg intranasal (2 nose) ☺ 0.1-0.15 mg/kg IM ☺ 0.5mg/kg orally ☺ 0.5-1mg/kg rectal (large dose)
Side effects of each route
Most common is
Oral - slow onset (most common) IM – pain Rectal - uncomfortable, defecation, burn Nasal -irritating Sublingual -bad taste
Roles on
Role when awake separation of child from
parent before induction is planned.
2. Its success may be judged by the peacefulness of
the separation.
3. Large volume of literature indicates lack of
clearly ideal technique
Versed PO: • Bioavailability = • Peak serum levels after\_\_\_\_\_\_ • Peak sedation by about\_\_\_\_\_\_\_ • 85% peaceful separation • Mix with
up to 12 mg max.
30%
about 45 minutes
30 minutes
Grape concentrate or acetaminophen
(Tylenol) syrup or elixir or Motrin Suspension (10
mg/kg of the 2% suspension)
Possible concern with versed
Nasal dose
animal studies reveal neurotoxicity after topical application.
0.2mg/kg, peak 10 minutes, higher doses may delay intubation
Methohexital (Brevital) rectal dose is _______as ____% solution in __________
• 85%__________________
induction of GA (very peaceful separation)
**Sleep duration:*
**Rectal 25 to 30 mg/kg as 10% solution in warm
tap water
sleeping within 10 minutes = rectal
about 45 to 90 minutes
Ketamine PO:\_\_\_\_\_\_\_\_\_ • May slightly prolong time to discharge after a short case • IM:\_\_\_\_\_\_\_\_\_\_ sedation; • 2 mg/kg did not delay recovery • 10 mg/kg:\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
6 to 10 mg/kg
3 to 4 mg/kg
as effective as Midazolam 1 mg/kg but
some delay in recovery may be expected
Ketamine• = __________IM induction of general
anesthesia
6 to 10 mg/kg
Midazolam + Ketamine:
DOSE
• PO 0.4 mg/kg + 4 mg/kg respectively
100% successful separation
Ketamine + Propofol in the same syringe
KETAFOL (50mg of ketamine in 50 mg of propofol)
Consider medication
Fentanyl Lollipo consideration
Glycopyrollate (ENT, airway surgery )
Can increase volume of gastric contents
EMLA cream:
Eutectic mixture of Lidocaine and Prilocaine.
MORPHINE
Water soluble? or lipid soluble?
Who does if affect more and why?
rectal administation =______–>______
Morphine 0.05-0.2 mg/kg ☺Water soluble = slow CNS ☺Neonates affected more → immature BBB ☺Rectal administration = delayed absorption → resp. arrest
MEPERIDINE dose only indicated for\_\_\_\_\_\_\_\_\_ \_\_\_\_\_Route not recommended \_\_\_\_\_\_Vd= \_\_\_\_\_\_\_Resp depression Long infusion leads to \_\_\_\_\_\_\_\_\_---> \_\_\_\_\_\_\_-->
Meperidine 1-2 mg/kg
☺Only indicated for anti-shivering, NOT analgesia
☺Rectal route not recommended
☺Larger Vd = less respiratory depression
☺ Long infusions → normeperidine → seizures
Fentanyl dose
Lipid or water soluble?
CV response?
Synergistic with what medication>?
–>1 mcg/kg
☺Lipid soluble, small molecules → efficient BBB
penetration and redistribution
☺Stable cardiovascular response
☺Synergistic with midazolam
☺Fast administration → chest wall + glottic rigidity
☺Can ↑vagal tone → bradycardia
Fentanyl too fast you can get
CHEST WALL and GLOTTIC RIGIDITY
Alfentanyl and Sufentanyl:
☺ More rapid clearance than adults
* Can cause parasympathetic response –>
bradycardia, hypotension**
Volume of distribution make succinylcholine
HIGHER DOSES in pediatric
More water
Succinylcholine dose _______
Laryngospasm breaking dose__________IV IM
GIVE WITH IT__________ or prior
Potential side effects:
☺ 1-2 mg/kg IV; 4.0 mg/kg IM ☺Laryngospasm breaking dose = 0.1mg/kg IV, 4mg/kg IM ☺ Consider Atropine 10-15 mcg/kg given prior SUX ☺ Potential side effects: Rhabdomyolysis Hyperkalemia Masseter spasm MH
Know ROC
0.1
Benzylisoquinoline: Atra and cisa Atra dose? Metabolism? Intubation condition in \_\_\_\_\_minuts Lasts \_\_\_\_\_\_mins
- Atracurium 0.5 mg/kg IV
- Hofmann elimination, ester hydrolysis
- Intubation conditions in 2-3 minutes
- Lasts 30 minutes
Cisatracurium
Dose
Daughter of __________
Same ______except____
0.15 mg/kg IV • Daughter of atracurium • Same elimination except NO ester hydrolysis • Same duration • Onset ↑with ↑ dose
Atracurium may give some
Airway issues
Potentiation of NMB with anesthesia gases in descending order:
DO NOT NEED TO MEMORIZE,
• isoflurane, desflurane, sevoflurane > nitrous oxide
• Per Barash: des > sevo > iso > N2O
Hoffman ALKALOSIS
Favor elimination
Hoffman acidosis
Less elimination
Aminosteroids
• Vecuronium
Rocuronium
Vecuronium dose is \_\_\_\_\_\_\_ CV effects Intubating conditions in \_\_\_\_\_\_ Metabolized \_\_\_\_\_\_, excreted \_\_\_\_\_\_\_ Who is sensitive?
0.1 mg/kg No adverse CV effects • Intubating conditions in 3-5 min • Metabolized by liver and excreted via bile • Infants significantly sensitive
Rocuronium dose?
compared to vec is ________? intubating conditions?
with HR?
0.6-1.2 mg/kg, 1.8mg/kg IM
• Faster acting than vecuronium, 0.5-1.5 min for intubating conditions depending on dose
• Transient ↑HR seen with higher doses
Reversal agents: Peds at high risk of
• Monitor
resp. failure w/residual NMB
- TOF at adductor pollicis
Clinical signs of NMB antagonism in infants:
Flex hips/arms, lift legs, return of abdominal muscle tone, inspiratory force of -25 cm H2O or greater (more negative)
• Hypothermia
potentiates NMB (makes muscle slower)
Potentiated by NMB
• Potentiated by magnesium
antibiotics: aminoglycoside derivatives (gentamicin, tobramycin, and neomycin) = greatest effect
Magnesium and HYPOCALCEMIA
Rule of 6
twitch and cc of neogstimine
4/4 twitch 6-4= 2 cc
1/4 twitch 6-1= 5 cc
*****CAN’T GO OVEr 5
Anticholinesterases • Neostigmine dose\_\_\_\_\_\_\_\_ • Require \_\_\_\_\_\_\_\_\_\_\_than adults • Doses >\_\_\_\_\_\_\_\_\_ • Co-administer with\_\_\_\_\_\_\_\_\_
0.020-0.025 mg/kg
0.1mg/kg can cause paradoxical weakness from ↑Ach at NMJ
smaller dose
glycopyrrolate 0.005-0.01 mg/kg
Sugammadex dose is Class Roc vs Vec encapsulates better Safe in peds? Worry about?
Sugammadex 2 mg/kg (moderate block; reversed in 1.2 min)
• Cyclic oligosaccharide
• Encapsulates rocuronium best, vecuronium less
• Studies have concluded safe to use for peds
• Worry about allergic/anaphylactic reactions
MAY GET BRADYCARDIA
FASTING Clear liquids -
☺ If infants are breast fed -
☺ For older patients =
☺ Be aware of
2-3 h before the procedure
4 h before the procedure
the adults rule
dehydration
Inhalational induction: After induction --> Use suggestions in older child --> What protects against anesthetic OD--> In a case of difficult airway --> \_\_\_\_\_\_\_\_\_
Younger than 12 months
☺ After the induction, place the intravenous catheter
☺ Use suggestions in older child (pilot’s mask)
☺Spontaneous ventilation protects against anesthetic
overdose
☺ In a case of difficult airway - Fiberoptic intubation
What agents used for RECTAL INDUCTION
☺ Methohexital (KeMidMethoThi) ☺ Thiopental ☺ Ketamine ☺ Midazolam ☺ Technique no more intimidating than rectal temperature measurement ☺ Usual time of onset ~ 10-15 min
Usual time of onset of RECTAL INDUCTION
10-15 min
IM induction
Most common used is ______
Disadvantage is _______
ADvantage ______
☺ Most common used Ketamine
☺ Disadvantage painful needle insertion
☺ Advantage: reliability
IV induction The most \_\_\_\_\_\_ and \_\_\_\_\_\_\_Technique Disadvantage is \_\_\_\_\_\_\_\_\_\_ if patient is older \_\_\_\_\_\_\_ If you insert the IV line" 3 things you should do?
☺ The most reliable and rapid technique
☺ Disadvantage - starting intravenous line
☺ If patient is older ask the patient
☺ If you insert IV line:
I. Do not allow the patient to see it
II. Use EMLA cream
III. If use local - ask the patient if there is any sensation on puncture
Patient with a FULL STOMACH
RSI with ________using _______
Tell the patient that will feel ________
Be aware of ________which leads to _______
What should you administer before Succinylcholine and why ?
Use _________dose ________
Use Succinylcholine dose _________
☺ RSI with ODL using cricoid pressure
☺ Tell the patient that will feel “touching on the neck”
☺ Be aware of Increased VO2 (desaturation)
☺ 0.02 mg/kg of Atropine administer before SUX to
avoid bradycardia (usually after 2nd dose)
☺ Use Rocuronium 1.2 mg/kg
☺ Use Succinylcholine 1-2 mg/kg if really need
short duration (difficult airway)
Premature infant -
Full-term infant -
3-12 month old child -
1 year and older child -
100 ml/kg
90 ml/kg
80 ml/kg
70 ml/kg
MABL
EBV (Starting Hct - TARGET hct)/ Starting Hct
Packed Red Blood Cells: ☺ Child usually tolerates Hct\_\_\_\_\_\_\_ ~ ☺ If the child is - - - ☺ No one formula permits a definitive decision ☺ Replace\_\_\_\_\_\_\_\_blood with \_\_\_\_\_Of L ☺ Be aware of blood disorders (sickle cell disease)
20 in mature children Premature, - Cyanotic congenital disease - Decreased O2 carrying capacity Hct ~ 30
1ml blood with 3 ml of LR
What is a late sign of decreased O2 carrying capacity
☺ Lactic acidosis
Bleeding and FFP rule of thumb
☺ A patient should be never given FFP to replace bleeding that is surgical in nature
Blood transfusion : If transfused faster than________ severe______May occur
1.0 ml/kg/min ionized hypocalcemia may occur
BLood transfusion Ionized hypocalcemia can occur in neonates frequently why?
because of decreased ability to mobilize Ca++ and metabolize citrate
Monitoring the Pediatric Patients:
☺ Must be consistent with the severity of the underlying medical condition ☺ Minimal monitoring: I. ASA monitors II. ***Precordial stethoscope*** III. Anesthetic agent analyzer
Special Monitoring the Pediatric
Patients:
☺ Intraarterial catheter - most common _______
☺ Pulmonary artery catheters are indicated or not? why?
☺ In a case of severe multisystem organ failure
What might be helpful ?
☺_____________atheters are valuable in ICU patients
☺ In a case of rapid fluid replacement ______________might be very useful
☺__________________________
or umbilical vein may be life-saving
☺ Intraarterial catheter - most common radial
☺ Pulmonary artery catheters are rarely indicated
because equalization of the pressure right/left heart
☺ In a case of severe multisystem organ failure
insertion of PAC might be particularly useful
☺ Multilumen catheters are valuable in ICU patients
☺ In a case of rapid fluid replacement peripheral
venous catheter might be very useful
☺ Short-term cannulation of femoral/brachiocephalic
or umbilical vein may be life-saving
How do nonrebreathing circuits work?
• Expiration →exhaled gas pushed down expiatory
limb and collects in reservoir bag and opens
expiratory valve (“pop-off, APL”)
• All NRB are convenient, light weight, and easily
scavenged
Recommended circuit in children is the
Use of _______is recommended in children < ___-kg
3 reasons?
☺Use of Mapleson D system is recommended in
children < 10 kg
• More sensitive to changes in gas flow
• More sensitive to humidification
• Actual delivered volume is greater than other systems
Mapleson D is \_\_\_\_\_\_\_\_ circuit \_\_\_\_\_\_\_\_\_\_ FGF tubing directed within the \_\_\_\_\_\_\_limb FGF enters \_\_\_\_\_\_\_\_\_ Adds more \_\_\_\_+\_\_\_\_\_\_
- Bain circuit
- “coaxial” Mapleson D circuit
- FGF tubing directed within the inspiratory limb
- FGF enters circuit near mask
- Adds more heat + humidity
Anesthesia Circuits: Non-Rebreathing Speeds-up rate of \_\_\_\_\_\_\_\_\_\_\_\_\_ •\_\_\_\_\_\_\_And \_\_\_\_\_\_\_\_\_\_ are less (small circuit volume) • No \_\_\_\_\_\_\_\_\_\_\_\_r = rebreathing highly dependent on \_\_\_\_\_\_\_\_ • Minimum FGF \_\_\_\_\_\_\_\_\_\_\_
All lack unidirectional valves • Minimal work of breathing Speeds-up rate of inhalational induction • Compression and compliance volumes are less (small circuit volume) • No CO2 scrubber = rebreathing highly dependent on FGF • Minimum FGF 5L/min (or 2-3 x MV)
Sugammadex only work for
ROCURONIUM > VECURONIUM
NOT for atracurium or cisatracurium
Gases have
MUSCULAR RELAXANT PROPERTIES
REDUCE doses of volatiles anesthetics because they also have muscular relaxant properties
KNOW SLIDE 38
