Peds Flashcards
What is the earliest age at which preoperative anxiolysis may be used? What is the oral dose of Midazolam?
Separation anxiety does not begin to develop until after 6 months of age
Oral dose of Midazolam is 0.5 mg/kg
What is the concentration of fetal hemoglobin at birth? When does it reach it’s lowest levels?
At birth, the concentration of hemoglobin F is about 80%
It reaches it’s lowest levels by 2 to 3 months of age
List 5 fundamental differences between the adult and neonate airway
The tongue of an infant is much larger than an adult
- increased risk of obstruction and difficulty visualizing the larynx
Larynx is located more cephalad (C3-C4) in neonates compared with adults (C4-C5)
- more anterior view during direct laryngoscopy
Infant epiglottis is narrow and omega-shaped compared with broad and flat in adults
- can create difficulty during laryngoscopy
Vocal cords are angulated in neonates compared with being perpendicular to the trachea in adults
- can cause difficulty with intubation
Larynx is funnel-shaped in neonates with the cricoid being the narrowest part, while adults have a cylindrical larynx with the glottis opening being the most narrow area
How high can fetal PaO2 rise when the mother is given 100% supplemental O2?
Fetal PaO2 does not rise above 45 mm Hg, even when 100% O2 is given to the mother, because of the high O2 consumption of the placenta, and the uneven distribution of maternal and fetal blood flow in the placenta
What is usually the first sign of a high spinal in infants?
Respiratory depression (apnea and hypoxia) - requires immediate intubation
Hypotension, 2/2 loss of sympathetic tone, is rarely seen in children under 5 years old
What gestational age is most at risk for retinopathy of prematurity? What is it’s mechanism? How can it be avoided?
ROP typically occurs in newborns who are born less than 35 weeks of age
- risk is negligible after 44 weeks
Mechanism:
- Hyperoxia leads to constriction of the retinal arterioles, resulting in swelling and degeneration of endothelium that disrupts retinal development
- When normoxic conditions return, vascularization resumes abnormally, causing scarring of the retina
Exposure if preterm infants to PaO2 greater than 80 mm Hg or prolonged periods of time should be avoided
- maintain saturation between 93 and 95% in premature newborns
At what pressures do you want an endotracheal air leak in children? How do you test for it?
There should be a small air leak around the endotracheal tube at peak inflation pressures of approximately 15 to 25 cm H2O.
The test can be performed by slowly increasing the airway pressure and listening with a stethoscope over the larynx to hear when a leak develops.
How can you estimate the appropriate depth of insertion of an ETT in a child?
For children over three: Age/2 + 12
A baby with an omphalocele should be evaluated for what other disorder?
Congenital heart disease
- occurs in up to 20% of patients with an omphalocele
Why do infants and children require higher doses of succinylcholine compared to adults?
Increased extra cellular fluid increases the volume of distribution
What is the usual timing of diagnosis of pyloric stenosis? What type of electrolyte abnormality is it associated with? What is the correct fluid resuscitation? How do you know when a child is optimized for surgery?
Usually diagnosed at 2 to 6 weeks of age
Associated with a hypochloremic, hypokalemic metabolic alkalosis
Resuscitation involves replacement of deficit with NS followed by maintenance fluid at 1.5 times normal without potassium
Semi-normalization of chloride (over 100) may be the best suggestion of optimization
- pH and K are not reliable indicators
What is the most common cause of neonatal bradycardia (
Respiratory failure leading to hypoxia and acidosis
What is the correct energy level when using a manual defibrillator in a pediatric patient?
Initial shock should be 2 J/Kg followed by 4 J/Kg for initial shocks
The spinal cord of newborns extends down to what level?
L3
When does the pulmonary vascular resistance of newborns decrease to that of adults?
2 to 3 months
Which pediatric patients are at risk for post-op apnea and must be admitted for observation? What type of anesthetic is preferred? What can be given to decrease risk? What if an infant already has a history of apnea/bradycardia?
Infants younger than 60 weeks post-conceptional age
- anemia is an additional risk factor
Spinal should be considered over GA, although regional plus sedation incurs same risk as GA
Caffeine administration has been shown to decrease risk
In an infant with a prior history, it is recommended to have a six-month interval free from any events before proceeding with elective surgery
At what age is the MAC requirement the highest?
3 months
Describe Down syndrome
Caused by trisomy 21
Features: Congenital cardiac defects (commonly endocarditis cusion defects) Short neck Small mouth Large tongue Thyroid dysfunction Atlanto-occipital instability
What are some possible manifestations of hypothermia in infants?
Increased total body O2 consumption Metabolic acidosis Hypoglycemia Delayed awakening Prolonged duration of muscle blockade Depression of ventilation
When taking care of a child with a myelomeningocele, what else should you consider?
Other pathologies associated with myelomeningocele:
- Hydrocephalus
- Congenital heart defects
- Short trachea - increased chance of bronchial intubation
- Latex allergy
What is the normal dose for caudal anesthesia in children? Are there any risks?
1 mL/kg of 0.25% Bupivacaine can generally cover procedures in the T10-S5 dermatomes (no difference between 0.125% and 0.25% Bupi)
Higher risk of dural puncture in infants than adults as the dural sac extends to the S3/4 level instead of S1 as in adults
What are some anesthetic associations with rare pediatric syndromes?
Klippel-Feil - cervical spine fusion
Down syndrome - endocardial cusion defects, atlanto-axial instability, subglottic stenosis
Beckwith-Wiedmann - hypoglycemia
Pierre-Robin - micrognathia, upper airway obstruction
Describe epiglottitis
An airway emergency that usually occurs in children aged 2-5 years
Caused by Haemophilus influenzae type B
Signs and symptoms include fever, profuse drooling, stridor, and inability to lay supine
- characteristic radiology finding is the “thumb sign” which shows swollen epiglottis along with prevertebral edema
Treatment includes ENT consult, early intubation, and antibiotics
- no attempts at stimulation or suction should be made
Anesthetic management should include sevoflurane inhaled induction in the sitting position, maintenance of CPAP during spontaneous ventilation, and avoidance of paralysis
Describe croup
Also called laryngotracheobronchitis
Usually caused by the parainfluenza virus
Signs and symptoms are viral prodrome, fever, and barking cough
- characteristic radiology finding is the “steeple sign” showing only mucosal edema
Treatment includes racemic epinephrine
What is the most important mechanism of heat generation in neonates/infants? What triggers it? What inhibits it?
Nonshivering thermogenesis from brown fat
Triggered by norepinephrine, glucocorticoids, and thyroxin
Inhibited by inhaled anesthetics and B-blockers
At what rate and what type of solution should initial IV fluid resuscitation in children be?
20 mL/kg of normal saline WITHOUT potassium
What pain medication is contraindicated in children following tonsillectomy? Why?
Codeine
- has been linked to several pediatric deaths, likely in “over-metabolizers”
What is prostaglandin E1 used for in neonates? What are the side effects?
PGE1 is used to maintain patency or reopen the ductus arteriosus in “ductal dependent lesions” to improve flow to either the lungs or systemic circulation
Side effects include:
- apnea
- hypotension (decreases both SVR and PVR)
- fevers
- CNS irritability
Why do infants have an increased work of breathing relative to adults? Why do they fatigue quicker?
Increased work of breathing due to:
- smaller airways cause increased resistance
- increased O2 consumption per kilo
- highly compliant chest wall leading to functional airway closure with each breath
Due to decreased proportion of diaphragmatic type I muscle fibers, infants are more susceptible to early fatigue
Compared to adults, why is induction of anesthesia in infants quicker?
4 main factors allow a more rapid rise of FA:FI
1) Infants have increased minute ventilation relative to FRC
2) Infants have a greater fraction of cardiac output that is distributed to vessel-rich organs
3) Infants have decreased blood:gas coefficients
4) Infants have decreased tissue:blood coefficients
What is the treatment of choice for intra-op hypotension in a neonate and why?
Atropine is the initial treatment of choice
Neonatal myocytes have poor lusitropy and cannot accomodate increases in preload
Myocytes are also insensitive to catecholamines, so perssors are ineffective
Describe the benefits of parental presence during induction of anesthesia (PPIA). How effective is it?
PPIA can help reduce the anxiety of a child (and possibly the parent) during induction of anesthesia
It is most beneficial when a calm parent accompanies the child
- anxious parents can worsen a child’s anxiety
PPIA is still less effective than PO Midazolam
