Pediatric Anesthesia 848th FST

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Pediatric Anesthesia 848th FST
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Objectives

• State normal vital signs for children
• Identify fasting guidelines for children
  undergoing surgery
• Describe fetal circulation vs. normal circulation
• Name five anatomical differences in children
• Explain anesthetic management of TE fistula,
  pyloric stenosis, gastroschisis, omphalocele, and
  necrotizing enterocolitis

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Definitions of Pediatric Patients

• Preterm Infant
• Weighs
• Term Infant
• 40 wks
• Neonate
• 1-30 days old
• Child
• 12 months- puberty

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Differences in Pediatric Patients
Cardiac CO is dependant on HR since stroke
volume is fixed, increased HR, decreased BP,
increased RR, decreased compliance of the
ventricles
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Respiratory

• the obligate nose breather
• Narrow nares, anterior and cephalad glottis (C4
  in child vs. C5-6 in adult)
• Large tongue, cricoid cartilage is narrowest part
  until 5 yrs of age
• Small FRC, closing capacity is FRC
• Slanting vocal cords with omega shaped epiglottis
• Surfactant production 23-24 wks gestation

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Respiratory

• TV (7-10 cc/kg) Dead space (2-2.5cc/kg) are
  consistent with adult volumes
• O2 consumption 2X the adult(6cc/kg/min)
• ETT sizes
• 16 age / 4 equal size in mm
• 10 age / 2 equals length in cm
• Appropriate size of ETT has leak at 15-20 cm
  H2O

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Respiratory
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Estimated Blood Volume

• EBV ml/kg
• Preemie 90
• Infant 80
• Toddler 75
• Child 72
• Adult male 70
• Adult female 65

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Fluid Management

• Maintenance
• 4ml/kg for first 10kg
• 2ml/kg for 10-20kg
• 1ml/kg for each 20 kg
  
• 
  
• So for a 27 kg child, the hourly fluid
  requirement is 67 CC!

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Pharmacological Differences

• Decreased protein binding
• Rapid induction and recovery rate due to
  increased CO to vessel rich group and ratio of
  alveolar ventilation to FRC
• Increased MAC
• 2-3 month olds have highest anesthetic
  requirement
• Immature hepatic biotransformation
• Cytochrome P450 system is functional at 1 month

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Pharmacological Differences

• Large volume of distribution
• ECF is large!!
• Renal function 70 until 1 year
• GFR at birth is 15-30 of adult
• Physiologic anemia occurs in the 9-12th week
• 10-11 g/DL
• Spinal cord ends at L3 in the child L1 in the
  adult
• Nonshivering Thermogenesis
• Major mechanism of heat production by metabolism
  of brown fat

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Anesthetic Implications

• Pre-op Evaluation
• Check for loose teeth
• Ask about recent upper respiratory infections
• Realize anxiety of family and child
• Fasting Guidelines
• Clears 2 hrs prior procedure
• Breast milk 4 hrs
• Formula/meals 6 hrs
• Fatty solids 8 hrs
• Versed .5mg/kg oral PRN

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Fetal Circulation

• 1 Umbilical vein 2 umbilical arteries
• Ductus Venosus
• Bypasses liver to shunt blood into right atrium
• Foramen Ovale
• Shunts blood from right atrium to left atrium
• Ductus Arteriosus
• Shunts blood from pulmonary artery to aorta
• P50 of fetal hemoglobin
• 19 vs. 27 in adult

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Fetal Circulation
RA RV PAX
FO DV
PARALLEL
LA LV aortainfant 2/3
ejection comes from RV, 1/3 comes from LV Heart
and brain well oxygenation, 7-8 in PA goes to
lungs
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Neonate

• ODC curve in newborn is shifted to left due fetal
  Hgb and high O2 affinity
• Newborn must overcome negative inspiratory
  pressures of 40-60cm H2O to overcome surface
  tension
• Diaphragmatic breathers due to poorly developed
  intercostal muscles
• Prone to atelectasis and hypoxemia during
  anesthesia

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Neonate

• Closure of the DA occurs initially at 10-15 hours
  after birth and permanently at 2-3 wks
• Reversible during hypoxemia or hypervolemia
• Foramen ovale is patent in approx 50 of children
  under 5 25 of adults
• This is key in potential air emboli
• Neonates have underdeveloped ANS until 4-6 months
• Can lead to bradycardia quickly
• Always check O2
• Atropine dose is .1mg min.

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Tracheoesophageal Fistula Esophageal Atresia

• Frequently associated with LBW, prematurity,
  other congenital anomalies
• Most common is esophageal atresia with blind
  dilated prox. Pouch
• Fistula between esophagus and trachea

• VACTER syndrome
• Vertebral defects
• Anal atresia
• Cardiac (VSD,ASD,TOF)
• TE fistula
• Esophageal atresia
• Renal anomalies and/or Radial defects
• 13000 births
• Not specific for race or sex

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Management of TE Fistula

• Monitoring
• EKG
• A-line
• NBP cuff
• Pre/post ductal pulse oximetry
• Pretreatment of the neonate with Robinul for
  excessive secretions
• Awake intubation is the safest for securing
  airway
• ET Tube placement confirmed by fiberoptics
• Suction, Suction, Suction!!!
• Avoid N2O
• Place G-Tube to control gastric distension

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Management of TE Fistula

• May be necessary to bronchially intubate then
  pull back until breath sounds can be heard
• Listen to be sure fistula was not intubated
• Maintain normothermia and deliver only necessary
  O2 to maintain saturation
• Concern for recurrent laryngeal nerve injury with
  intubation
• Principle causes of death
• Pulmonary complications (62)
• Assoc. anomalies (43)
• Anastomotic leaks (21)

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Pyloric Stenosis

• 1300 births, males have a greater incidence than
  females
• Usually presents between 2-5 weeks of age
• Not a surgical emergency
• Hypertrophy of pyloric smooth muscle causes
  increased gastric pressure, which produces
  regurgitation and non-bilious vomiting
• Metabolic disturbances
• Hypochloremia
• Hypokalemia
• Hyponatremia
• Metabolic acidosis

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Pyloric Stenosis

• Neonate will have some degree of dehydration that
  will need to be treated with IV fluid and
  electrolyte restoration
• MANAGEMENT
• Maintain hydration intraop
• Preoperatively place an NG tube to empty the
  stomach contents
• Pretreat with Robinul

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Pyloric Stenosis

• Awake intubation can be done in a less vigorous
  infant or in an infant that has had barium
  recently
• Otherwise, proceed with a rapid sequence
  induction after preoxygenation
• EXTUBATE THE INFANT WHEN THEY ARE FULLY
  AWAKE!!!
  

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Congenital Diaphragmatic Hernia

• Caused by the incomplete closure of the diaphragm
• Occurs in 15000 births
• The most common site of the defect is the
  posteriolateral, pleuroperitoneal canal (Foramen
  of Bochdalek)
• Fetal lung development is affected by the
  impingement of bowel resulting in lung hypoplasia
• Hypoplasia of the left ventricle can also occur
  resulting in cardiac insufficiency

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Management of Diaphragmatic Hernia

• Patients will often be intubated when they come
  to the OR
• If not, awake intubation is preferred after
  preoxygenation
• Monitor peak airway pressure to avoid
  pneumothorax
• Maintain between 25-30 cm H2O
• Place A-line and at least one IV line should be
  above the diaphragm
• Prolonged post-op ventilation is usually required

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Management of Diaphragmatic Hernia

• Volatile anesthetics are acceptable to use with
  avoidance of N2O
• Can use air/O2 mix if tolerated
• Narcotic and muscle relaxant technique may be
  used if tolerated
• Generally not recommended to reinflate
  hypoplastic lung since normal lung tissue can be
  damaged
• Patients usually have an underdeveloped abdomen
  that is difficult to close
• The patient will have increased airway pressures
  and decreased FRC

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Omphalocele Gastroschisis
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Omphalocele Gastroschisis

• A congenital defect of the anterior abdominal
  wall
• Allows the external herniation of abdominal
  contents
• For both, adequate maintenance of IV fluid is
  crucial
• Keep neonate warm
• Warm
• Room
• Fluids
• Overhead light
• Warming blanket
• Standard monitoring plus
• A-line
• CVP
• Foley should be placed
• Careful I O

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Omphalocele Gastroschisis

• Awake intubation with pre O2, after
  decompressing the stomach
• Volatile anesthetic with O2/air can be used
• No N2O!!!
• Narcotic muscle relaxant are preferred
• Underdeveloped abdomen with difficult closure
• Monitor airway pressures and adequate ventilation
• It may be necessary to cover abdomen with Dacron
  dressing
• Mechanical ventilation usually maintained post-op
  for 24-48 hours

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Necrotizing Enterocolitis

• One of the most common illnesses that affect
  premature infants
• Neonates at greatest risk
• Less than 32 weeks gestation
• Multifaceted etiology any problem leading to
  hypoperfusion to GI tract (asphyxia, infection,
  etc..) true cause unknown

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Necrotizing Enterocolitis Management

• Monitor all problems that occur with prematurity
• Awake or rapid sequence intubation should be
  performed place NG to decompress stomach
• Standard monitoring plus A-line and CVP
• Volatile anesthetics may not be tolerated

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Necrotizing Enterocolitis Management

• Fentanyl Ketamine may be best choice
• Avoid N2O
• Be prepared to RESUSCITATE these neonates, have
  code sheet with calculated doses ready
• Maintain body temperature with use of warming
  lights, blankets, and warm fluids
• Monitor ABGs and electrolytes

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Acute Epiglottitis

• High fever (39 C)
• Difficulty swallowing
• Edema of supraglottic structures
• Inspiratory stridor
• Signs Symptoms
• Drooling
• Lethargy
• Sitting forward
• Tachypnea
• Cyanosis

• Physiologic Presentation
• Acidotic
• Dehydrated
• Elevated CO2
• Decreased pH
• May develop sudden airway obstruction
• Need intubation
• Cause is Haemophilus influenza
• Lasts 2-4 days

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Acute Epiglottitis

• Treatment is Ampicillin and Hib vaccine is
  available
• Take over airway when diagnosis is made
• Intubate and extubate in OR
• Exam of upper airway is limited to
• Noting RR
• Assessing work of breathing
• Respiratory distress
• No manipulation or exam of the mouth or pharynx
  unless in controlled setting
• No blood work done or IV placed

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Acute Epiglottitis Management

• Child should remain sitting on parents lap and
  given supplemental blow by O2
• Avoid disturbing child
• Transport child mother together with
  resuscitation equipment
• In OR, have tracheostomy and rigid bronch set up
  available
• No muscle relaxant or sedation until airway
  established
• Induce in sitting position
• Keep child breathing
• Need small tube and have positive air leak
• Observe closely

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Laryngotracheobronchitis

• Slow onset
• Signs Symptoms
• Low grade fever (
• Less airway obstruction
• Croupy cough
• Rhinorrhea
• Inspiratory stridor
• Management O2 Humidity

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Pierre-Robin Syndrome

• Patients can present with cleft palate
• Small face and glottis
• Intubation very difficult
• Awake intubation
• Fully awake before extubation

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Treacher Collins Syndrome

• Small mouth with deformity
• More severe than Pierre Robin syndrome
• Intubation very difficult
• Use awake technique
• Fully awake before extubation

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Prune Belly Syndrome

• Signs Symptoms
• Thin abdominal wall
• Renal involvement
• Inability to cough well
• Possible pulmonary complications
• Treat as full stomach
• Awake intubation
• Intubate and assist or control ventilation
• No muscle relaxation
• Use drugs excreted by kidney with care

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Questions