Peds Flashcards
Neonates
0-1 month
Infants
1-12 months
Toddlers
12-24 months
Young Children
2-12 years
Key Concept
Neonates and infants have fewer and smaller alveoli, reducing lung compliance.
Neonnates and infants have cartilaginous rib cages making their chest wall very compliant, increasing airway resistance.
Work of breathing is increased, and respiratory muscles more easily fatigue.
These characteristics promote chest wall collapse during inspiration and relatively low residual lung volumes at expiration.
The resulting decrease in FRC limits oxygen reserves during periods of apnea and predisposes neonates and infants to atelectasis and hypoxemia.
In neonates and infants, the effects of reduced FRC may be exagerrated by relatively higher rate of oxygen consumption compared to adults.
Neonates/infants: cc/kg/min
Adults: cc/kg/min
In neonates and infants, the effects of reduced FRC may be exagerrated by relatively higher rate of oxygen consumption compared to adults.
Neonates/infants: 6-8 cc/kg/min
Adults: 3-4 cc/kg/min
AIrway anatomical differences in neonates/infants?
Larger head
Shorter neck
Larger tongue
Narrow nasal passages
Obligate nasal breathers (until about 5 months)
Shorter trachea
Prominent adenoids/tonsils
Anterior/cephalad larynx (glottis at C4 vs C6 in adults)
Longer epiglottis
Waker intercostal and diaphragmatic muscles
Greater resistance to airflow
_ is the narrowest point of the airway in children younger than 5 years of age.
_ is the narrowest point of the airway in adults.
The cricoid cartiladge is the narrowest point of the airway in children younger than 5 years of age.
The glottis is the narrowest point of the airway in adults.
Neonates and infants have _ lung compliance and _ chest wall compliance.
Neonates and infants have REDUCED lung compliance and INCREASED chest wall compliance.
The cardiac output of neonates/infants is dependent on _.
The cardiac output of neonates/infants is dependent on heart rate.
Cardiac stroke volume is relatively fixed by the immature, noncompliant left ventricle in neonates and infants. The cardiac output is therefore very sensitive to changes in heart rate.
Although basal heart rate is greater in neonates and infants than adults, vagal stimulation, anesthetic overdose, or hypoxia can quickly trigger bradycardia with profound reductions in cardiac output.
The immature heart is more sensitive to depression by volatile anesthetics and to opioid induced bradycardia.
The sympathetic nervous system and baroreceptor reflex are also not fully mature. The infant cardiovascular system displays a blunted resposne to exogenous catecholamines.
What factors promote greater heat loss to the enviroment in neonates?
Think skin
Low fat content
Greater surface area relative to weight
Why are neonates predisosed to hypoglycemia?
Relatively reduced glycogen stores
NOTE:
In general, neonates at greatest risk for hypoglycemia are premature or small for gestational age, are receiving total parenteral nutrition, or had mothers with diabetes.
Total body water content of a neonate?
80%
Total body water content of an infant?
70%
Why do neonates and infants have a faster inhalation induction than adults?
Neonates and infants have relatively greater alveolar ventilation and reduced FRC. This greater minute ventilation to FRC ratio contributes to a rapid increase in alveolar anesthetic concentration. Combined with relatively greater blood flow to the brain.
Why is the blood pressue of neonates and infants more sensitive to volatile anesthetics?
The blood pressure of neonates and infants appears to be especially sensitive to volatile anesthetics. This clinical observation has been attributed to less well-developed compennsatory mechanisms (eg. vasocontriction, tachycardia) and greater sensitivity of the immature myocardium depressants.
Why is succinylcholine generally avoided in pediatric anesthesia?
Children are more susceptible than adults to cardiac arrythmias, hyperkalemis, rhabdo, myoglobinemia, masseter spasm, and malignant hypertheria associated with succinylcholinne.
Children may have profound bradycardia and sinus node arrest following the first dose of succinylcholine without atropine pretreatment.
NOTE:
Generally accepted indications for IV succinylcholine in childrin include RSI with a “full” stomach and laryngospasm that does not respond to positive-pressure ventilation.
NPO guidlines
Clear liquids- 2 hours before induction
Breast milk- 4 hours before induction
Formula / light meal- 6 hours before induction
Uncuffed ETT size
> 1 yr old
age of patient / 4 + 4 = size of ETT Internal Diameter
Cuffed ETT size
> 1 yr old
(Age of patient/4 +4) - 0.5= size of ETT
ETT size for patients < 1 yr old
Preemie = 2.5-3.0
Neonate = 3.0-3.5
9 months-1 yr = 4.0
What are routes of administration of midazolam for anxiolysis in pediatric patients?
Nasal (onset 5-10min)
Oral (onset 20-30min)
Rectal
IV
IM
Risk factors for persistent fetal circulation?
Maternal use of NSAIDs
Maternal diabetes
Maternal asthma
C-section
Asphyxia
Congenital diaphragmatic hernia
Meconium aspiration
How do pediatric airways differ from adults?
Larger occiput
Large tongue
Cephalically displaced larynx
Funnel shaped larynx
Anteriorly displaced vocal cords
Short Omega shaped epiglottis
Elipitical subglottis
The most important muscle of respiration in the neonate is
The diaphragm
Why are children and infants more susceptible to hypothermia than adults?
Less insulating subcutaneous fat
Higher surface area-to-volume ratio
Neonates produce heat through…
Neonates produce heat through non-shivering thermogenesis (metabolism in brown fat)
Parental Presence during Induction of Anesthesia (PPIA) is most beneficial for patients between what ages?
Parental Presence during Induction of Anesthesia (PPIA) is most beneficial for patients between the age of 1-6 years old.
Patient under what age are at risk of hypoglycemia during surgery?
< 6 months
Hence why glucose containing solutions of 1-2.5% dextrose may be added.
For healthy pediatric patients undergoing elective surgery, current perioperative fluid management guidelines recommend how much fluid over 2-4 hours?
For healthy pediatric patients undergoing elective surgery, current perioperative fluid management guidelines recommend a bolus of 20-40cc/kg of isotonic solution administered over 2-4 hours.
For the first postoperative 12 hours, pediatric maintenance IV fluids should be calculated by using what rule?
2-1-0.5 rule
NOTE:
This recommendation replaced the previous 4-2-1 rule because of increased morbidity and mortality associated with excess perioperative ADH secretion and hyponatremia.
Management strategy for repair of Congenital Diaphragmatic Hernia?
Low TVs
Permissive hypercapnia (PaCO2 up to 65mmHg)
Maintenance of preductal SpO2 90-95%
Maintenance of normothermia
Prevention of worsening pulmonary hypertension
Anesthetic considerations for patients with Down Syndrome
What is the difference between an omphalocele and gastroschisis?
Omphalocele is a congenital condition in which abdominal organs (intestines, liver, stomach) protrude through an abdominal wall defect near the umbilicus with an overlying hernia sac.
Gastroschisis is a congenital condition in which abdominal organs protrude through a defect (commonly to the right of the umbilical cord) with once difference being that it has NO associated hernia sac.
Omphaloceles are commonly associated with what congenital cardiac abnormalities?
Septal defects (specifically VSDs)
NOTE:
Studies estimate up to 80% of patients with omphaloceles have associated congenital heart disease (CHD).
DiGeorge Syndrome (deletion of 22q11.2) is commonly associated with what congenital heart abnormality?
Tetralogy of Fallot
NOTE:
Mnemonic “PROVE”:
Pulmonary stenosis
RVH
Overriding aorta
VEntricular septal defect
Turner syndrome is commonly associated with what cardiac abnormalities?
Bicuspid aortic valve
Coarctation of the aorta
Coarctation of the aorta is commonly associated with
Coarctation of the aorta is commonly associated with:
Bicuspid aortic valve
Persistent ductus arteriosus (PDA)
VSD
How does coarctation of the aorta manifest?
Headache
Epistaxis
Dilated costal arteries
CHF
NOTE:
Due to increase in upper body flow and pressure
What are the four types of ASDs?
Ostium primum
Ostium secundum (most common)
Sinus venosus defect
Cornary sinus defect
NOTE:
Patent foramen ovale (PFO) is a subclass of the ostium secundum defect, it is not a defect of the “true septum.” The patent foramen ovale is the most common septal anomaly and occurs when ends the septum primum, and the septum secundum do not approximate and close the foramen ovale after the child breathes its first breath.
NPO guidelines for formula
6 hours
Patent Foramen Ovale (PFO) is the result of failure of fusion of..
Patent Foramen Ovale (PFO) is the result of failure of fusion of the septum primum and septum secundum.
NOTE:
Prevalence of 25% in the general adult population.
Compared with an ASD, there is tissue of the septum secundum present but there is failure of fusing.
Ostium secundum ASD is the most common type of ASD (75%), and occurs due to
Ostium secundum ASD is the most common type of ASD (75%), and occurs due to missing tissue of the septum secundum that leads to the large ostium secundum.
Ostium secundum ASA is associated with
Mitral valve prolapse
Mitral valve regurgitation
Ostium primum ASD is a rare type of ASD and is associated with
Cleft formation in the anterior leaflet of the mitral valve
Sinus venosus is a rare type of ASD (10%) and is associated with
Partial anomalous return of the Right Upper Pulmonary Vein (RUPV). The RUPV drains into the SVC, right atrium, and IVC.
What is a coronary sinus defect?
Coronary sinus defect: The coronary sinus is a vessel that runs along the groove between the left atrium and left ventricle and collects veins that represent the venous return of the heart muscle. It normally drains into the floor of the right atrium above the septal leaflet of the tricuspid valve. A defect or hole in the common wall between the left atrium and the coronary sinus (called “unroofing” of the coronary sinus) creates a communication between the right and left atria.
How does transposition of the great vessels occur?
Failure of the aorticopulmonary septum to spiral.
Transposition of the great vessels is a reversal of positions of the aorta and the main pulmonary artery due to failure of the aorticopulmonary septum to spiral. The aorta is positioned anteriorly and exists the right ventricle while the pulmonary artery is positioned posteriorly and exists the left ventricle. This leads to complete separation of the pulmonary (now left sided) and the aortic (now right sided) circulations.
Describe the pathophysiology of Hypoplastic Left Heart Syndrome (HLHS).
Hypoplastic Left Heart Syndrome (HLHS) is a congenital condition such that the left ventricle and outflow tract are underdeveloped and hypoplastic. This results in the inability to support systemic circulation.
As a result of the hypoplastic left ventricle, the right ventricle maintains perfusion for both pulmonary and systemic circulation, with the survival of the infant dependent on a patent ductus arteriosus (allows for systemic perfusion) and atrial septal defect (allows for mixing deoxygenated and oxygenated blood).
Additional features may include mitral and/or aortic valve atresia, hypoplasia, or stenosis and/or hypoplasia of the ascending aorta and aortic arch.
The surgical management of Hypoplastic Left Heart Syndrome (HLHS) consist of what three-staged procedures?
The surgical management of Hypoplastic Left Heart Syndrome (HLHS) consist of the following three-staged procedures:
1- Norwood
2- Glenn
3- Fontan
“Never Gave a Fuck”
The surgical management of Hypoplastic Left Heart Syndrome (HLHS) consists of a three-staged procedures.
How is the Norwood procedure performed?
The Norwood procedure creates a new aorta as well as a shunt from the right ventricle to the pulmonary arteries.
The surgical management of Hypoplastic Left Heart Syndrome (HLHS) consists of a three-staged procedures.
How is the Glenn procedure performed?
The bidirectional Glenn procedure results in the attachment of the SVC to the pulmonary arteries, allowing deoxygenated blood to return to the pulmonary circulation from the upper body.
The surgical management of Hypoplastic Left Heart Syndrome (HLHS) consists of a three-staged procedures.
How is the Fontan procedure performed?
The IVC is attached to the right pulmonary artery allowing deoxygenated blood to return to the pulmonary circulation from the lower body.
At what age is the Norwood procedure performed?
Within the first week of life
At what age is the Glenn procedure performed?
4-6 months old
At what age is the Fontan procedure performed?
2-5 years
NPO guidelines for breast milk
4 hours
NPO guidelines for non-human milk
6 hours
Why are preterm infants < 60 weeks post-conceptual age (PCA) admitted to the hospital for 24 hours after general and regional anesthesia?
Apnea monitoring, because apnea spells are common in preterm infants.
Why do neonates have decreased oxygen reserve compared to adults?
Tidal volumes in the neonate are similar to the adult on a volume per kg basis.
They have increased respiratory rates which thereby increases the neonate’s minute ventilation as compared to the adult. The neonate has a higher minute ventilation due to their higher oxygen consumption.
The neonate’s closing volume is higher and can approach their normal tidal volume which can result in premature closure of small airways.
With a similar functional residual capacity compared to the adult but a higher minute ventilation, the neonate’s ratio of minute ventilation to FRC is two to three times higher.
This leads to a decreased oxygen reserve but a faster inhalation induction in the neonate.
