Knowledge Navs Exam 2 Flashcards
Rhabdomyolysis has been reported after succinylcholine in children with ____________
Duchenne and Becker muscular dystrophy.
The dose response of rocuronium in children with Duchenne muscular dystrophy shows ____________
marked prolongation of both the onset and recovery times (two to three times normal).
NMBDs in children with severe pre-existing respiratory dysfunction
caution
even a small dose of a NMBD may cause profound muscle weakness and the need for ventilatory support.
Children with syndromes are relatively sensitive to NMBDs because ____________
Most are relatively sensitive to the NMBDs, particularly those with muscular dystrophy, because of muscle wasting.
NMBDs in children with burns
may require two to three times the usual IV dose of nondepolarizing relaxants.
what is the blood volume of a preterm infant
90-100 mL/kg
blood volume of a term neonae
80-90 mL/kg
blood volume of infant 3 months to 1 year
70-80 mL/kg
blood volume of older child
70 mL/kg
A healthy child readily tolerates a hematocrit well below ____________
30%
It is our practice not to transfuse otherwise healthy infants up to about 3 months old until their hematocrits have decreased to ____________ and hematocrits of older children have decreased to ____________ if there is little potential for postoperative bleeding.
25%; 20%
A unit of whole blood can provide …
- 1 unit of PRBCs
- 1 unit of whole blood–derived platelets
- 1 unit of fresh frozen plasma (FFP)
Succinylcholine-induced muscle fasciculation is associated with (3)
- mild hyperkalemia
- increased intragastric and intraocular pressures
- skeletal muscle pains
what effects of succinylcholine may occur in patients with neuromuscular disorders?
rhabdomyolysis and myoglobinemia
The serum potassium concentration increases ____________ after IV succinylcholine in normal children; this increase does not cause arrhythmias
1 mEq/L or less
Succinylcholine in children with burns
Succinylcholine can cause hyperkalemia in children with burns, which may cause a cardiac arrest.
smallest burn that has been associated with hyperkalemia
8%
the first 24 hours after a burn and succinylcholine
hyperkalemia after succinylcholine has not been reported in the first 24 hours after a burn
Hyperkalemia is thought to result from ____________ along the surface of the muscle membrane in the postburn phase.
the upregulation of acetylcholine receptors
succinylcholine IV dose for < 1 yr
2-3 mg/kg
succinylcholine IM dose for > 1 yr
4-5 mg/kg
For brief cases in which children are anesthetized with 8% inspired sevoflurane, 0.3 mg/kg rocuronium yields satisfactory intubating conditions within ____________
2 to 3 minutes.
0.3 mg/kg of Rocuronium can be antagonized within approximately ____________ of administration
20 minutes
PONV relation to age in children
PONV is inversely related to age in children
PONV ↑ or ↓ throughout childhood
↑
The incidence of PONV in children is greatest after what kind of surgeries?
tonsillectomy, strabismus repair, hernia repair, orchiopexy, microtia, and middle ear procedures
after puberty who experiences more PONV
girls experience much more than boys
The medical complications of PONV include…
pulmonary aspiration, dehydration, electrolyte imbalance, fatigue, wound disruption, and esophageal tears.
PONV can produce what kinds of effects in children
psychological effects that may produce anxiety in the children and parents and lead them to avoid further surgery.
The most effective prophylaxis strategy in children at moderate or high risk for PONV is to use combination therapy that includes …
- hydration
- a 5- HT3-receptor antagonist
- a second drug such as dexamethasone
A dose of ____________ at the end of surgery effectively reduces emesis after strabismus surgery and tonsillectomy, although the magnitude of its effectiveness may be limited
0.15 mg/kg of metoclopramide
metoclopramide mechanism of action
- The antiemetic properties result from its direct effects on the chemoreceptor trigger zone.
- Gastric emptying is a result of the antagonism of the neurotransmitter dopamine, which stimulates gastric smooth muscle activity
Some studies report that ____________ is superior to metoclopramide (0.15 mg/kg) for the prophylactic control of postoperative vomiting in children undergoing tonsillectomy.
ondansetron (0.1 mg/kg)
Most pediatric anesthesiologists limit their routine of 5-HT3 antagonist use to …
children undergoing procedures known to have a substantial incidence of PONV, such as:
- strabismus repair
- tonsillectomy
- middle ear surgery
- to children with a known history of motion sickness or previous nausea and vomiting after surgery
The usual recommended dose is 100 to 150 μg/kg every 6 hours.
The usual recommended dose of ondansetron is ____________
100 to 150 μg/kg every 6 hours
A number of studies in children demonstrated that the antiemetic effect of drugs from this class can be improved if they are combined with ____________ or other anesthetic techniques known to reduce vomiting.
dexamethasone
Rapid administration of FFP is more likely to be associated with ____________ than the transfusion of components with smaller volumes of plasma (e.g., PRBCs).
citrate toxicity
what is initial dose of FFP in peds
10-15 mL/kg
T/F FFP contains functional platelets
false, no functional platelets, leukocytes, RBCs
midazolam IV dose in peds
0.05-0.15 mg/kg
____________ is the only benzodiazepine approved by the FDA for use in neonates, including preterms
midazolam
how is midazolam metabolized
hepatic hydroxylation (CYP3A4) ➔ excreted in urine
midazolam clearance in neonates
reduced
The suggested infusion rate of midazolam is ____________ for preterm infants younger than 32 weeks gestational age
0.5 μg/kg/min
The suggested infusion rate of midazolam is ____________ for infants infants greater than 32 weeks gestational age
1 μg/kg/min
prolonged admin of midazolam
tolerance, dependency, and benzodiazepine withdrawal
Accordingly, one must wait sufficient time between doses of midazolam ____________ to achieve the peak CNS effects before considering supplemental doses or other medications
(3–5 minutes)
diazepam dose
0.2-0.3 mg/kg
half life of diazepam
20-80 hours
metabolism of diazepam
demethylation by CYP 2C19
which benzodiazepine is painful when given IV or IM and what can you do to treat it?
diazepam, use lido!
diazepam in infants and neonates
Avoided in infants and neonates because of prolonged t ½ and metabolites
hypothermia in infants and coagulation
- may worsen major blood loss and replacement
- compromises platelet function & impairs coagulation cascade
hypothermia and oxygen consumption
may ↓ O2 consumption and demand ORRRRR increase consumption through shivering
hypothermia shift of oxygen-hemoglobin dissociation curve
left shift
in the presence of severe hypothermia (about 32°C) what may occur to cardiac rhythm
refractory ventricular tachycardia
only allowable method to give warmed blood
Blood warmer device
what happens to RBCs if they are overheated > 42º C
RBCs hemolyze
Ways to maintain thermal neutrality:
- Warming blood and all other IV infusions with a high-capacity blood warmer
- hot air warming blankets and - radiant warmers
- plastic wrap around extremities
- heated humidifier in the anesthesia circuit
- covering the head
- maintaining a warm to hot operating room
what does hypothermia do to most nondepolarizing muscle relaxants
potentiates them and delays elimination
How can shivering affect NMB?
Shivering increases oxygen consumption. If respiratory muscles cannot match this → hypoxemia and CO2 retention →acidosis → potentiates NMB.
the infant should be warmed if temperature is
< 35º C
mild to moderate hypothermia in infants
may cause apnea in infants, alter the pharmacokinetics of medications, decrease blood clotting and increase surgical site infections
how does MAC change with temperature
decreases MAC; in children 4 to 10 years, the MAC of isoflurane decreases 5% per degree Celsius
most common route of heat loss in infants
radiation (39%)
the transfer of energy through the generation of electromagnetic waves to solid surfaces such as cold walls
radiation
the transfer of energy from the child by the gas or liquid surrounding it. It can be passive, as in still air, or active when air flows past the infant
convection
the loss of heat as liquid is converted to gas. This is typically seen through perspiration but can also occur with major open wounds, and dissipation of cleansing preparation solutions
evaporation
the transfer of energy directly from one body to another and can occur in solids, liquids, and gases. Based on their material, objects are conductors (metals) or insulators (gases)
conduction
minimum acceptable Hct varies according to ____________
individual need
which populations often require a greater hematocrit
severe pulmonary disease or cyanotic congenital heart disease often require a greater hematocrit
preterm infant hematocrit requirement is higher bc…
prevent apnea, reduce cardiac and respiratory work, and possibly improve neurologic outcomes
healthy infant 3 months old transfusion threshold
Do not transfuse healthy infants up to about 3 months old until their hematocrits have decreased to 25%
MABL in Children
what medication is directly related to PONV in peds
the morphine dose
> 0.1 mg/kg correlates with a 50% or more incidence in vomiting
Latino children and morphine
Latino children 4x more pruritus and 7x more vomiting with similar morphine and morphine metabolite values.
ondansetron dose in children
100 to 150 µg/kg every 6 hours
risks of ondansetron
ventricular tachyarrhthmias (Torsades) if long QT syndrome, esp when using inhalationals (sevoflurane)
which agents are better for chemo induced N/V
Granisteron and tropisteron
metoclopramide effects
Gastric emptying: dopamine antagonism, which stimulates gastric smooth muscle activity
dose of metoclopramide
0.15 mg/kg at the end of strabismus and tonsillectomy surgery
Neurokinin 1 Antagonists mechanism of action
- in the brainstem (area postrema and nucleus tractus solitarius)
- receptor for substance P
procedures with high risk of PONV
strabismus repair, tonsillectomy, or middle ear surgery
upper airway obstruction not included
longitudinal stretch during inspiration
laryngospasm
Incidence of laryngospasm after maintenance of anesthesia with ____________ is significantly less than with ____________ .
propofol, sevoflurane
The effects of spraying the vocal cords with lidocaine on the incidence of laryngospasm and bronchospasm
effects are unclear
Prophylactic treatment with glycopyrrolate, ipratropium, or albuterol (does/ does not) affect the incidence of URI-related adverse events.
does not
Prophylactic ____________ reduced perioperative airway sequelae in children with URIs.
salbutamol
laryngospasm is accompanied by
an inspiratory effort, which longitudinally separates the vocal from the vestibular folds.
what is physiologically similar to involuntary laryngeal closure
Glottic closure during forced expiration (forced glottic closure or Valsalva maneuver)
hallmark high-pitched inspiratory stridor is caused by
the upper portion of the larynx to be partially open during mild laryngospasm
how to relieve laryngospasm
Anterior and upward displacement of the mandible (jaw thrust applied at the condyle of the ascending ramus of the mandible)
how does jaw thrust work
Longitudinally separates the base of the tongue, the epiglottis, and the aryepiglottic folds from the vocal cords.
predominantly inspiratory stridor suggests
- an upper airway (extrathoracic) lesion: epiglottitis, croup, extrathoracic foreign body
both expiratory and inspiratory stridor suggests what kind of lesion
an intrathoracic lesion
- aspirated foreign body, vascular ring or large esophageal foreign body
expiratory stridor or prolonged expiratory phase can suggest
lower airway disease
RDS can cause (3)
- Reduced lung volumes and lung compliance
- Increased intrapulmonary shunting
- Ventilation-perfusion mismatch
clinical manifestations of RDS
- Grunting respirations
- Nasal flaring
- Chest retractions that develop shortly after birth
infant normal RR
30-53
1-3 y/o normal RR
22-37
4-5 y/o normal RR
20-28
6-12 y/o normal RR
18-25
13-18 y/o normal RR
12-20
The upper airway compromises…
the nasal cavities, oral cavity, pharynx, and larynx.
The mucosa that lines the upper airway is loose-fitting ____________
pseudostratified columnar epithelium
pressure on the mucosa may cause ____________
reactive edema that encroaches on the diameter of the lumen.
Because the subglottic region in the infant is smaller in the adult, the same degree of airway edema results in ____________
greater resistance in the infant.
Upper airway patency is maintained by
connective tissue and by sustained and cyclic contractions of the pharyngeal dilator muscles.
tongue in neonate
large in proportion to the rest of the oral cavity and more easily obstructs the airway, especially in the neonate.
larynx in infants
more cephalad at C3-4 (adults C4-5)
how many cartilages and bones in larynx
1 bone, 11 cartilages
The vocal cords are covered with ____________
stratified epithelium
branches of superior laryngeal nerve
- internal branch → sensory innervation to the supraglottic region
- external branch → motor innervation to the cricothyroid muscle
recurrent laryngeal nerve function
sensory innervation to the subglottic larynx and motor to all other laryngeal muscles.
____________ is the only laryngeal function that alters the cricothyroid angle.
phonation
Despite significant airway obstruction during inspiration, it may still be possible to ____________
phonate.
____________ is functionally the narrowest portion of the upper airway.
the cricoid cartilage
Growth of the subglottic airway occurs rapidly during
the first 2 years of life
Cricoid and thyroid cartilages reach adult proportions by ____________
10-12 years of age
The____________ is the only complete ring of cartilage in the laryngo tracheobronchial tree - nondistensible.
cricoid
how are vocal cords angled
Angled such that the anterior insertion is more caudad than the posterior insertion
where might the tip of the ETT be held up
at the anterior commissure of the vocal folds
infant epiglottis
shape & angle
narrow, omega shaped, and angled away from the axis of the trachea
why is the peds epiglottis shaped like that?
Shape allows the epiglottis to approach the uvula during infant breastfeeding - separating breath from fluid and allowing respiration at the same time as swallowing.
upper lip bite
focused airway exam
defibrillation pads placement for infants < 25 kg
pads placed on chest and back
defibrillation pads for kids > 25 kg
pads placed on R. and L. lateral chest
joules/kg of pediatric defibrillation
2 joules/kg
For V fib/Vtach defibrillation:
2 joules/kg ASYNCHRONOUS;
repeat up to 4 joules/kg
For SVT/Vtach cardioversion:
0.5 joules/kg SYNCHRONOUS;
repeat up to 2 joules/kg
crystalloid boluses
10-20 ml/kg (up to 3 boluses)
colloid bolus amount
20 mL/kg
RBC or FFP bolus amount
10-20 mL/kg
what is the apnea-hypopnea index (AHI)
Summation of the number of obstructive apnea and hypopnea events
obstructive sleep apnea syndrome
periodic cessation of air exchange with apnea episodes lasting longer than 10 sec and AHI indicating the total number of obstructive sleep episodes per hour of sleep is greater than 1
AHI 1-5
mild OSA
AHI 6-10
moderate OSA
AHI > 10
severe OSA
what is commonly given as a topical cream for transdermal local anesthetic
lidocaine and prilocaine
what might Eutectic Mixture of Local Anesthetics (EMLA) cause
may cause vasoconstriction and blanching, making placement of IV difficult
there is a high risk of ____________ with EMLA
methemoglobinemia
what is methemoglobinemia
hemoglobin is converted into methemoglobin; decreases available O2 carrying capacity and increases affinity of unaltered hemoglobin for O2, which further impairs O2 delivery
neonates have ↑ or ↓ methemoglobin reductase activity compared to older children and adults
reduced activity
atropine dose
0.02 mg/kg
younger than 6 months require larger doses to increase heart rate
what might atropine and scopolamine cause
decreased ability to sweat ➔ increase in temperature
Central sedative effects of both atropine and scopolamine are antagonized with ____________
physostigmine
atropine admin in T21 patients
may have narrow-angled glaucoma- caution with administration can worsen
scopolamine dose
0.01 mg/kg
uses of anticholinergics
diminish secretions preoperatively
block laryngeal and vagal reflexes
treat or prevent the bradycardia from succinylcholine,
treat the bradycardia of anesthetic-induced myocardial depression
muscarinic effects of neostigmine
oculocardiac reflex
red vs infrared light
red- 660 nm
infrared- 930 nm
do SCD and fetal hemoglobin impact pulse oximetry?
no
If otherwise safe for the neonate; the oxygen saturation measured by pulse oximetry (SpO2) is between ____________ to minimize the risk of oxygen toxicity without increasing perioperative mortality.
91% and 95%
when is a low FiO2 desirable
(1) congenital heart disease to reduce the oxygen saturation to balance the pulmonary and systemic blood flows
(2) airway surgery to reduce the risk of airway fires
(3) in infants and neonates to reduce the risk of retinopathy of prematurity
inspiration ____________ venous return to the heart
increases
exhalation ____________ venous return to the heart
decreases
when is pulsus paradoxus more pronounced?
when there is a decrease in the central venous filling pressure (hypovolemia) or if there is a significant increase in the inspiratory force (upper airway obstruction)
____________ is an algorithm used to predict patients whose cardiac output might benefit from fluid bolus
Pleth Variability Index (PVI)
when is an uncuffed ETT used
patient less than 8
when is cuffed ETT used
patient older than 8
uncuffed ETT size
age/4 + 4
cuffed ETT size
age/4 + 3 (or 3.5)
children with down syndrome require a ____________ ETT
smaller diameter
children with cardiac disease often require a ____________ ETT
larger size
A sustained inflation pressure of ____________ should be applied to detect an audible or auscultated air leak over the glottis
20 to 25 cm H2O
If no leak is detected, the ETT size is …
excessive and it should be exchanged for one with an ID 0.5 mm smaller
distance for ETT insertion
size x 3
1000 g ETT size
2.5
1000-2500 g ETT size
3.0
neonate to 6 month ETT size
3.0 - 3.5
6 months - 1 year ETT size
3.5 to 4.0
1 to 2 years ETT size
4.0 - 5.0
who acts as the decision maker for children and legally can give conset
the parents
age group consent vs permission
- <6 years no decision-making capacity - best interest standards
- 6-12 years developing- informed permission informed assent
- 13-18 years mostly developed- informed permissions informed assent
- Mature minors developed- informed consent
- Emancipated minor developed- informed consent
recommendations for risk communication to patients
If an adolescent has a positive pregnancy test before anesthesia. Given the principles of confidentiality, it is ethically appropriate to inform ____________
only the adolescent.
Necessary emergent care for minors who do not have a parent available to give legal consent should be ____________
provided regardless
greatest risk age group for preop anxiety
ages 1-5
____________ % of children develop fear and anxiety before surgery
40-60%
signs of pre-op anxiety
- scared or agitated, breathe deeply, tremble, stop talking or playing, and start to cry.
- some may wet or soil themselves, display increased motor tone, and actively attempt to escape from medical personnel
Children who are 6 years or older benefit from ____________ before the surgery
a prep program 5 days
prep program had a negative impact for what age group
children less than 3
ADVANCE Prep program
Children with dynamic obstruction to the left or right ventricular outflow tracts often benefit from sedative premedication because ____________
crying and struggling during induction may worsen obstruction
Premedication for infants younger than 6 months of age
is usually unnecessary
onset of midazolam
the only premedication approved for neonates
Midazolam
midazolam provides ____ amnesia
anterograde
Midazolam can cause respiratory depression and hypotension if given with
fentanyl
Midazolam dosing
- 0.1mg/kg IV
- 0.5 -1.0 mg/kg PO Most commonly used
- 0.2 mg/kg nasal
T/F:
Versed causes pain on injection in pediatric patients.
False
water soluble
Ketamine dosing
(mg/kg)
* oral
* rectal
* nasal
* IM
BZD dosing (mg/kg)
Clonidine dose
0.004 mg/kg PO
You can give morphine IM at what dose
0.1-0.2 mg/kg
Give demerol IM at what dose
1-2 mg/kg
Fentanyl Oral and nasal dosing
Barbiturates dosing (thiopental and methohexital in mg/kg)
Basic vs acidic drugs and which plasma protein they bind to
- Basic drugs (lidocaine or alfentanil) bind to plasma a1 acid glycoprotein (AAG)
- Acidic drugs (diazepam, barbiturates) bind to albumin
“Basic girls like the Alpha guys”
Neonates have (decreased/increased) protein binding, which means…
decreased
greater unbound drug ready for passive diffusion
Neonates have factors that both decrease and increase medication levels bc…
- reduced clearance = increased medication levels
- increased Vd = decreased medication levels
kernicterus from medications
- Medications that compete with bilirubin to bind to albumin cause hyperbilirubinemia
- Phenytoin, salicylate, caffeine, ceftriaxone, hypaque
Likely to cause methemoglobinemia
EMLA
2.5% lidocaine and 2.5% prilocaine
T/F:
Iodine antiseptics likely to cause hyperthyroidism
False
HYPOthyroidism
T/F:
Neonates and infants have the same MAC requirements.
False
less in neonates than in infants
The difference in the potency (or MAC) of inhalational anesthetics varies inversely with ____
lipid solubility
What begins at approximately 0.6 MAC?
decrease in vascular resistance causes a reciprocal increase in CBF
The speed of induction dependent on
(4)
- potency/MAC of the agent
- rate of increase of the inspired concentration
- maximum inspired concentration
- respiration
Prop
pediatric maintenance infusion rate
200-250 mcg/kg/min
An approrpiate way to warn about injection pain from propofol
“warmth” or “sunshine on your arm”
Propofol induction dose
3-4 mg/kg
Prop
distibution and Cl
Rapid re-distribution, hepatic and extrahepatic clearance (lung, kidney)
Prop allergy is due to the
egg white protein
T/F:
Prop has less emergence delirium than inhalations and less PONV
True
To eliminate pain with propofol injection, pretreat with
- IV lidocaine (0.5 mg/kg),
- meperidine,
- nitrous oxide,
- metoprolol,
- dexmedetomidine,
- low dose ketamine or tramadol
PRIS risk, infusion at rates greater than
5 mg/kg per hour
The Propofol ED50 for loss of eyelash reflex
- 1–6 months: 3 ± 0.2 mg/kg
- 1–12: 1.3 - 1.6 mg/kg
- 10–16: 2.4 ± 0.1 mg/kg
- ED90-95 LOER for all ages is 50% to 75% > ED50.
- no premedication: propofol (per kg) required for loss of the eyelash reflex is generally inversely r/t age
Methohexital (brevital)
is a (short/long)-acting barbiturate
short
Methohexital (brevital)
IV induction dose
1-2.5 mg/kg
T/F:
Expect airway obstruction but not desaturation with Methohexital
False
Oxygen desaturation 4% of cases and can cause airway obstruction (reposition head)
Methohexital (brevital)
SEs
Pain on injection
Hiccups
Seizure-like activity
T/F
Methohexital can be given rectally as a premedication
True
Methohexital Clearance
0.76 L/minute per 70 kg
Thiopental
moA
Binds GABAA receptors to prolong chloride channel opening
Thiopental CL
0.24 L/minute per 70 kg
(less than Brevital)
Thiopental
IV induction dose
3-4 mg/kg
Duration of effect depends primarily on redistribution rather than metabolism (10% per hour)
Thiopental
Thiopental
effects on myocardium vs vasculature
Myocardial depressant & weak vasodilator (little direct effect on vascular smooth muscle tone)
T/F:
Prop causes a greater hypotensive response than thiopental in neonates.
True
The hypotensive response in neonates given thiopental appears not as dramatic as propofol
Ketamine
moA
NMDA receptor antagonist
Ketamine induction doses
1 - 3 mg/kg IV
5-10 mg/kg IM
Ketamine peak concentrations are reached within
10 minutes after 4 mg/kg
IM??
Ketamine
desirable effects
Analgesic & amnestic, dissociative amnesia
Bronchodilator
Ketamine
UNdesirable effects
- Direct cardiac depressant
- May precipitate seizures in susceptible children
Side effects: nystagmus, increased secretions, 30% increase in intraocular pressure, increased intracranial pressure (cerebral vasodilation) & CMRO2
Do adults or peds get higher doses of Ketamine? Why?
Doses are typically larger in children due to greater clearance than in adults
Ketamine CV effects and how to lessen them
- increased HR & BP, little effect on pulmonary artery pressure
- fewer cardiovascular effects with the dextro isomer
Ketamine Cl
- neonates is reduced (26 L/hour per 70 kg)
- matures to reach adult rates
(80 L/hour per 70 kg; that is, liver blood flow) within the first 6 months of life
Why use ketamine IM?
combative larger children
Etomidate
moA
Steroid-based hypnotic induction agent
Etomidate
is metabolized by
hepatic esterases
Etomidate
suppresses adrenal function for up to…
24 hours
Etomidate dosing
0.2 - 0.3 mg/kg IV, typically 30% increase in dose in children due to increased volume of distribution
T/F:
Etomidate is appropriate for head injuries
True
and CV unstable
T/F:
Etomidate has no effect on hemodynamics
True
Etomidate side effects
- Emesis
- Adrenal suppression
- Pain on injection
Neonates need (less/more) NMB.
less
increased sensitivity
Why do neonates need less NMB?
- Neuromuscular transmission is immature until 2 months old
- Reduction in acetylcholine released
- Reduced muscle mass
- Reduced clearance
The neonate’s diaphragm function may recover earlier than peripheral muscles bc…
Type 1 (slow twitch) diaphragm muscle fibers are most sensitive to NMBDs
BUT
preterm neonate has only ~10% type 1 fibers
T/F:
Neonates and infants need lower doses of NMB than adults.
False
Neonates have increased sensitivity
Infants require larger doses than adults
Why do infants need higher NMB dose than adults?
Larger volume of distribution due to greater total body water & extracellular fluid
T/F:
Neonates have faster NMB onset due to greater cardiac output
True
T/F:
Infants are more resistant to Suxx than adults
True
How to dose atropine when giving Suxx
10-20 mcg/kg
every 5-10 minutes
Suxx has rapid redistribution in
extracellular fluid volume
Succinylcholine dose
infants: 3 mg/kg IV or 5 mg/kg IM
children 1.5- 2mg/kg IV or 4 mg/kg IM
Infants more resistant than adults
T/F:
You will not see defasiculations from suxx in a toddler
False
1-3 years old can see fasciculations but don’t see them in infant
Succinylcholine side effects
- increased masseter muscle tone when given with halothane - masseter spasm potential sign of malignant hyperthermia
- Arrhythmia - bradycardia due to choline metabolites; more likely with 2nd dose
- Hyperkalemia - normal increase K+ ~1 mEq/L; higher in burns, motor neuron lesions & neuromuscular disease
- Increased intraocular pressure
How much does Suxx increase K?
What worsens this?
1 mEq/L
higher in burns, motor neuron lesions & neuromuscular disease
What is plasma cholinesterase (pseudocholinesterase)
circulating glycoprotein that metabolizes succinylcholine into succinylmonocholine
Which conditions decrease and increase plasma cholinesterase activity
Decreases: severe liver disease, malnutrition, organophosphate poisoning, severe burns, renal failure, plasmapheresis, cyclophosphamide, echothiophate iodide, oral contraceptives
Increases: thyroid disease, obesity, nephrotic syndrome, cognitively challenged children
Fastest onset of non-depolarizing relaxants
Roc
Roc dose may need to be increased if
doing TIVA
Which NMB?
Spontaneous degradation not dependent on plasma cholinesterase
Cisatracurium
T/F:
Children recovery slower from cisatracurium than adults
False
Faster recovery in children due to greater volume of distribution & total body clearance
T/F:
Vecuronium is metabolized by liver and excreted in urine
False
excreted in bile
this is correct for Roc
Who is more sensitive to Vec?
infants or children?
infants <1
are more sensitive to vec compared to children
T/F:
Vec has no CV effects
True
Which NMB is not used in peds?
Pancuronium
Long-acting
> 50% excreted in urine unchanged, 10% in bile
Side effect: tachycardia - blocks presynaptic noradrenaline uptake
NMBs by dose
infants and children
MAC for neonates
What determines Wash In of inhalation agents
how does CO affect FA/FI
lower CO = more rapid increase FA/FI
T/F:
The slower the FI of nitrous oxide the more rapid the increase FA/FI
False
faster
T/F:
Neonates have more bradycardia and hypotension with increasing volatile anesthetics compared to adults
True
Immature sarcoplasmic reticulum in cardiac cells = poor Ca retention and release
Premeds can be given for:
(6)
- anxiety,
- block vagal responses/reflexes,
- reduce airway secretions,
- amnesia,
- GI prophylaxis,
- facilitate induction and analgesia
Premedicant drugs include:
- Tranquilizers: Versed, diazepam, Lorazepam
- BARBs
- Nonbarbiturate sedatives:
- Chloral hydrate and triclofos
- morphine, fentanyl, sufenta, tramadol, butorphanol, codeine
- Ketamine
- A2 agonists (clonidine, precedex)
- AntiACh
- Topicals (EMLA, ELA Max, S-caine patch
- Tylenol (2+Y)
- corticosteroids
major effect of tranquilizers is to allay anxiety but they also have the potential to
produce sedation
Tranquilizers
This group of drugs includes:
Benzodiazepines (widely used in children)
Phenothiazines + Butyrophenones (infrequently used)
T/F:
Benzodiazepines cause minimal drowsiness and cardiovascular or respiratory depression at low doses.
True
most widely used premedication for children
Midaz
major advantage of midazolam over other drugs in its class
rapid uptake and elimination
Midazolam duration and half life
- short-acting, water-soluble
- elimination half-life of approximately 2 hour
Versed routes
IV, IM, nasally, PO, rectally with min irritation
Bitter taste when given PO + nasally
Versed dose
Most children are adequately sedated with:
- 0.025 to 0.1 mg/kg IV
- 0.1 to 0.2 mg/kg IM
- 0.25 to 0.75 mg/kg orally
- 0.2 mg/kg nasally
- 0.1 mg/kg rectally
T/F:
required dose of midazolam increases as age decreases in children
true
CYP 450 Inducers
(↓ DOA Versed)
- anticonvulsants (phenytoin and carbamazepine)
- rifampin
- St. John’s wort
- glucocorticoids
- barbiturates
T/F:
PO Versed is effective in sedation but increases residual volume
False
effective and does NOT increase gastric pH or residual volume
CYP 450 Inhibitors
(prolonged sedation w/ Versed)
- grapefruit juice
- erythromycin
- protease inhibitors
- calcium-channel blockers
Increased postoperative sedation may be attributed to synergism between
propofol and midazolam on GABA receptors
children can become agitated after giving midazolam by which route?
wyd?
oral
IV Ketamine (0.5 mg/kg) may reverse the agitation
Nasal versed
- onset
- effectiveness
- onset: anxiolysis + sedation within 10 mins
- not well accepted because it causes irritation, discomfort + burning aftertaste
T/F:
IV Versed can cause neurotixicity.
False
Nasal
Potential to cause neurotoxicity via the cribriform plate (use preservative free only)
Diazepam should only be used for premedication of older children bc…
infants + premies immature hepatic function causes markedly prolonged elimination half life
Diazepam
Active metabolite:
- desmethyldiazepam
- pharmacologic activity equal to diazepam with half life > 9 days
Most effective routes for diazepam
IV
(followed by PO then rectal)
T/F:
Like Versed, Diazepam can be given IM.
False
do not give Diazepam IM
pain + erratic absorption
Lorazepam
dose
(0.05 mg/kg): PO, IV, or IM
These BZDs are reserved primarily for older children
Diazepam
Lorazepam
Why use Lorazepam instead of Diazepam?
Causes less tissue irritation + more reliable amnesia than diazepam
Inactive metabolites
IV form of this BZD is avoided in neonates because it may be neurotoxic
Lorazepam
Diazepam vs Lorazepam
onset
doA
Lorazepam is slower and longer
advantages of barbiturates
minimal respiratory or cardiovascular depression, anticonvulsant effects, and a very low incidence of nausea and vomiting
relatively short-acting barbiturates thiopental and methohexital may be given rectally as a
10% solution
T/F:
Barbiturates are infrequently used for premedication
True
How to give rectal thiopental or methohexital
30 mg/kg via a shortened suction catheter, which produces sleep in about two-thirds of the children within 15 minutes
10% solution
What to monitor for when giving rectal thiopental or methohexital
sedation may be profound, resulting in airway obstruction and laryngospasm
always have: source of oxygen, suction, and a means for providing ventilatory support
disadvantages of rectal methohexital
- unpredictable systemic absorption
- defecation
- hiccups
Children chronically treated with _____ are more resistant to the effects of rectally administered methohexital
phenobarbital or phenytoin
Contraindications to methohexital
- hypersensitivity
- temporal lobe epilepsy
- latent or overt porphyria
do NOT give rectal if rectal mucosal tears or hemorrhoids
Nonbarbiturate sedatives
- Chloral hydrate and triclofos
- orally administered nonbarbiturate drugs used to sedate children
- both are slow onset and relatively long acting
Chloral hydrate
is rarely used bc…
- unreliable
- has a prolonged DOA
- unpleasant taste
- irritating to skin mucosa & GI tract
Chloral hydrate use in ____ is not recommended because of impaired metabolism
neonates
Opioids:
SEs
N/V, respiratory depression, sedation, + dysphoria
All children that receive opioid premedication should be…
continuously observed + monitored with pulse ox
Morphine IV dose
0.05 to 0.1 mg/kg
Other than IV, what routes can we give Morphine?
Pros and cons
IM
Also effective when given PO
rectally not recommended because erratic absorption
____ are more sensitive to the respiratory depressant effects of morphine (rarely used)
Neonates
Fentanyl:
was introduced in a “lollipop” delivery system known as
oral transmucosal fentanyl citrate (OTFC)
no longer used for this
T/F:
Fentanyl has a moderate incidence of PONV
False
HIGH
Which opioid is Currently used to treat breakthrough cancer pain
Fentanyl
How to utilize Fentanyl
administered nasally (1 to 2 µg/kg)
primarily after induction to provide analgesia in children without IV access
Sufentanil is ___ times more potent than fentanyl
10
Sufenta
administered nasally in a dose of
1.5 to 3 µg/kg
Sufenta isnt a popular choice for premedication bc….
the adverse effects
more PONV and reduced chest wall compliance and prolonged hospital stay
After giving this drug for premideication, children are usually calm and cooperative, and most separate from their parents with minimal distress
Sufenta
Tramadol
moA
weak µ-opioid receptor agonist
analgesic effect is mediated via inhibition of norepinephrine reuptake and stimulation of serotonin release
How does Tramadol affect breathing and bleeding?
devoid of action on platelets and does not depress respirations in the clinical dose range
Tramadol
peak
doA
metab
- Serum concentrations peak by 2 hours after oral dosing
- analgesia for 6 to 9 hours.
- metabolized by CYP2D6
Butorphanol
moA
synthetic opioid agonist-antagonist with properties similar to those of morphine that can be administered nasally
Butorphanol:
most frequent adverse effect
sedation that resolves approximately 1 hour after administration
Tramadol
how much and when to give
dose of 0.025 mg/kg administered nasally immediately after the induction
Opioids + Midazolam
more respiratory depression than opioids or midazolam alone
decrease dose of both
Codeine is a prodrug that must undergo _____ in the liver to produce morphine to provide effective analgesia
O-demethylation
oral codeine dose
0.5 to 1.5 mg/kg
Codeine
onset
duration
- onset within 20 minutes
- peak effect between 1 and 2 hours
- elimination half-life 2.5 to 3 hours.
combination of codeine with acetaminophen is effective in relieving
mild to moderate pain
Some children do not get analgesia from codeine. Why?
5% and 10% of children lack the cytochrome isoenzyme (CYP2D6) required for conversion
A normal codeine dose in these children can be an overdose
obstructive sleep apnea
altered mu receptors and increased analgesia
Ketamine
moA
Dissociates cortex from limbic system, producing sedation and analgesia
but preserves airway reflexes and respiratory drive
bronchodilation
Ketamine uses
pre-med, opioid-sparing adjunct, in asthmatics
Ketamine preserves airway reflexes and respiratory drive but what are the cons?
- hallucinations, nightmares,
- nystagmus,
- sialorrhea,
- increased PONV
- high doses IM = more psychological effects
You’re giving Versed to mitigate the negative psych effects on Ketamine. What should you consider?
versed mitigates this but prolongs recovery from anesthesia
“Ketamine Dart”
high concentration Ketamine,
+/- versed,
+/- antisialagogue
Ketamine with the addition of _____ is recommended to decrease sialorrhea
atropine or glycopyrrolate
IM ketamine is an effective means of sedating which pts?
combative, apprehensive, or developmentally delayed children who are otherwise uncooperative and refuse oral medication
Ketamine IM dose
IM: 2-5mg/kg, EA 3-5min
- 2mg/kg, +/- 0.1-0.2mg/kg versed, for mask induction
- 4-5mg/kg for induction dose if BP stability needed (CHD)
- Up to 10mg/kg for up to 25 min need- most SE (good for burn pts)
Ketamine PO dose
PO: 5-6mg/kg, EA 12 min
3mg/kg + 0.5mg/kg versed works better and did not prolong recovery in cases longer than 30min
T/F:
Oral ketamine alone or in combination with oral midazolam is an effective premedication to alleviate the distress of invasive procedures
True
Nasal ketamine dose, usage, onset
6 mg/kg
effective premedication
sedation developing by 20 to 40 minutes
Rectal ketamine dose, absorption, & uses
- 5 mg/kg
- good anxiolysis and sedation within 30 minutes
- but unreliable absorption
Clonidine
moA
α2-agonist
dose-related sedation by its effect in the locus coeruleus
T/F:
Clonidine attenuates the hemodynamic response to intubation
True
acts both centrally and peripherally to reduce blood pressure
T/F:
Clonidine is devoid of respiratory depressant properties, even when administered in an overdose
True
T/F:
Clonidine decreases MAC requirements but may prolong emergence.
False
does not prolong emergence
T/F:
Oral clonidine 4 µg/kg reduces the incidence of vomiting after strabismus surgery
True!
Oral clonidine offers sedation and analgesia but must be given _____ before induction
60 mins
impractical in busy outpatient setting
Dexmedetomidine
moA
(not as common as clonidine)
- Great affinity for alpha-2 receptors
- produces sedation
- reduces postop opioid requirements
- useful as opioid sparing adjunct
- improves separation anxiety
T/F:
In contrast to clonidine, Precedex in higher doses can prolong emergence and recovery
True!
esp in combination with other sedating drugs
Precedex
Beware of _____ with rapid dosing
bradycardia
Precedex dosing
- PO: 2-4mcg/kg, effective in 20-30min
- IN: 2-3mcg/kg, effective in 30-45min
- IV: up to 1-1.5mcg/kg over 10min, effective in ~15min
Anticholinergics:
Uses
- prevent bradycardia from agents (sux, halothane)
- Block vagal reflexes from surgical stimulation (laryngoscopy, insufflation, strabismus repair)
- Decrease secretions
AntiACh SEs
tachycardia, dry mouth, impaired sweating
Scopolamine and atropine cross BBB- may cause agitation, confusion, restlessness, memory loss
AntiACh
Safety in pediatrics
with neonates, have atropine ready
kids are HR dependent
0.01-0.02mg/kg
Glyco- consider thoughtfully d/t uncomfortable s/e of dry mouth
0.01mg/kg
Atropine vs Glyco strength
Glyco is twice as potent at blocking secretions and lasts 3x longer
careful consideration when giving glyco
Topical Anesthetics:
EMLA
Lidocaine & Prilocaine
Occlusive dressing for one hour
Can cause vasoconstriction and blanching- increased difficult IV
ELA-Max
4% lido
Requires only 30min
Less vasoconstriction than EMLA
S-caine patch
lido and tetracaine
Heat controlled patch for accelerated delivery- only 20min
Theoretically should dilate
Acetaminophen
FDA approved for children….
2 years and older
Tylenol dosing
- PO: 10-15mg/kg
IV:
*2-12yrs: 15mg/kg q6hrs
* 1month- 2yrs: 12.5mg/kg q6hr or 10mg/kg q4h (max 50-60mg/kg/day)
* FT neonates up to 28days: 7.5mg/kg q6hr (max 30mg/kg/day
Who should get Corticosteroids as premedication?
currently taking or who have discontinued chronic corticosteroid treatment in the last 6 mons
Corticosteroids
usual recommended dose
hydrocortisone IM or IV: 1-2 mg/kg
or
equivalent of dexamethasone (0.05 to 0.1 mg/kg)
1 hour before induction or as soon as IV access is established
How long do we wait between corticosteroid doses?
dose may be repeated every 6 hours for up to 72 hours
GI drugs
dosing chart
Only a single dose of ____ is recommended due to metabolites that can cause seizures
meperidine
TABLE 4.4
Surgical Antibiotic Prophylaxis (Weight-Normalized)
