Anesthesia for Neonatal & Pediatric
Surgeries
Fetene S.
BSc, MSc, Lecturer of Anesthesia
Department of Anesthesia
Debre Berhan University
Module objectives
At the end of this module, you will be able to:
• Provide perioperative anesthetic care for pediatrics and lifethreatening neonatal emergencies.
2
Module Outline
• Introduction to neonatal and pediatrics anesthesia
• Basic principles of pediatric anesthesia
• Preoperative evaluation of the pediatric patient
• Pediatric anesthesia risk and complications
• Anesthetic for child with congenital anomalies
• Anesthetic for neonatal surgical urgencies and emergencies
3
Principles of pediatric anesthesia
Session objectives
At the end of this session you will able to:
• Define neonate, infant, and children
• Describe the principles of pediatric anesthesia
• Perform Pediatric basic and advanced cardiac life support
5
Children Are Not Little Adults
Categories
• Gestational age
• Birth weight
• Age group
•
•
•
•
•
•
Premature infant <37 weeks
Full term 37-40 weeks
Neonate Birth to 1 month
Infant 1 month to 1 year
Children 1 month to 12 year
12 years to 16 years Adolescents
Transition - Neonatal resuscitation
• Review of uteroplacental circulation
• Physiology of transitional circulation
• Fetal circulation is characterized
• The presence of three shunts:
o Ductus venosus
o Ductus arteriosus
o Foramen ovale
• High
pulmonary
vascular
resistance (PVR)
• Low systemic vascular resistance
(SVR) .
Persistent fetal circulation
• Under certain circumstances, the newborn may revert back to a
fetal-type circulation.
• In the presence of certain stimuli, the pulmonary arterioles will
constrict and lead to an increase in Pulmonary Vascular
Resistance (PVR).
• These stimuli include:
o Hypoxia
o Hypercarbia
o Acidosis
o Cold
Initial assessment of the newborn
• Evaluation begin as soon as the baby is handed over.
• Neonatal evaluation and treatment are carried out
simultaneously.
• Assessment begins with answering the following questions:
▪ Is the oropharynx clear of meconium?
▪ Is the baby breathing or crying?
▪ Is there good muscle tone?
Keep Warm!!!
▪ Does the baby have good color?
▪ Is the baby full term?
• If the answer is Yes … If the answer is No …
• Respirations and Heart rate are the most valuable assessment of
the neonate.
• Color, muscle tone, and reflex irritability also should be assess.
• Comprehensive screening tool --- to assess newborns at birth
• Appearance, Pulse, Grimace, Activity, Respiration
Apgar score
• Dr. Virginia Apgar created the system in 1952
• Her name as a mnemonic for the five categories.
•
•
•
•
•
A: Activity/muscle tone
P: Pulse/heart rate
G: Grimace (response to stimulation)
A: Appearance (color)
R: Respiration/breathing
• Based on a total score of 1 to 10.
• A score of ≥7 is a sign good condition.
Apgar score
Score*
Criteria
Mnemonic
0
1
2
Color
Appearance
All blue,
pale
Pink body, blue
extremities
All pink
Heart rate
Pulse
Absent
< 100 beats/minute
> 100 bpm
Reflex response to nasal
catheter/tactile
stimulation
Grimace
None
Grimace
Sneeze, cough
Active
Good, crying
Muscle tone
Activity
Limp
Some flexion of
extremities
Respiration
Respiration
Absent
Irregular, slow
* A total score of 7–10 at 5 minutes is considered normal; 4–6, intermediate; and 0–3, low.
• At birth ≈10% will need some assistance with ventilation and 1%
will need extensive resuscitation.
• As a member of the labor and delivery team, the anesthetist
should be skilled in the techniques of neonatal resuscitation.
Risk factors for the need of newborn resuscitation :
• Antepartum factors
•
•
•
•
•
•
•
•
Maternal comorbidities
2nd or 3rd trimester bleeding
Polyhydramnios
Oligohydramnios
Fetal anemia
Post-term gestation
Fetal anomalies
Premature or preterm rupture
membranes
• Intrapartum factors
of
•
•
•
•
•
•
•
•
•
•
Chorioamnionitis
Placenta previa, Placental abruption
Non-reassuring fetal heart rate tracing
Use of general anesthesia, Opioids
Prolapsed cord, Abnormal presentation
Forceps or vacuum-assisted delivery
Premature labor
Meconium-stained amniotic fluid
Macrosomia
Prolonged labor
Neonatal resuscitation supplies, equipment and medications
• Suction equipment
• Bag-and-mask equipment
• Intubation equipment
• Medications
Neonatal Resuscitation Algorithm
Neonatal Resuscitation Algorithm
Neonatal resuscitation supplies, equipment and medications
• Suction equipment
• Bag-and-mask equipment
• Intubation equipment
• Medications
Chest compressions in the neonate
• Thumb-over-thumb technique
• Two-finger technique
Medications for newborn resuscitation
• Epinephrine IV 0.01–0.03mg/kg ---- can repeat q3-5min
• Epinephrine ETT 0.1mg/kg (1ml) ---- give with PPV
• IV fluid 10–20ml/kg NS, LR, or blood
• Naloxone 0.1mg/kg IV/IM --- acute maternal opioid
• NaHCO3 2mEq/kg .IV --- give slowly
• Glucose 10% 8mg/kg/min --- documented hypoglycemia
• Dopamine 5mcg/kg/min
• Calcium gluconate 100mg/kg or CaCl2, 30mg/kg
Basics of Paediatric Anaesthesia
Session objectives
At the end of this session you will able to:
• Explain anatomical differences between pediatric and adult patients
• Explain physiological differences between pediatric and adult patients
• Explain the pharmacological considerations of pediatric patients.
• Describe the thermoregulation mechanism of pediatric patients
• Explain the psychological considerations of pediatric patients.
• Communicate with children and their caregivers
25
What makes Pediatric Anesthesia different?
• Outline the important anatomic and physiologic features
of pediatrics and appropriate, strategies that may be used
to overcome these.
1.
2.
3.
4.
5.
Airway considerations.
Respiratory system considerations
Cardiovascular system considerations
Renal, hepatic, glucose, hematologic considerations
Thermoregulation and psychological consideration
Basic considerations for pediatric anesthesia
• Anatomic consideration relevant to pediatric anesthesia
• Physiologic consideration relevant to pediatric anesthesia
• Pharmacological consideration relevant to pediatric anesthesia
• Thermoregulation mechanisms of pediatrics age group
• Psychological consideration of pediatric patients
Airway considerations
• Large head and occiput
• Relatively large tongue, adenoid and tonsil
• High anterior larynx
• Large, Floppy, Omega shaped epiglottis
• Short, narrow and soft trachea
• Narrowest portion at cricoid ring
• Funnel shaped larynx
• Narrow nasal passenger
Epiglottis
4 mm
Narrowest Area of Larynx
1 mm edema
Infant
75% loss of cross-sectional area
Airway Compromise
Size (mm ID)
Cuffed
1kg
1 – 2.5 kg
Neonate – 6months
6months – 1year
1 – 2 years
Size(mm ID)
Uncuffed
2.5
3.0
3.0 - 3.5
3.5 – 4.0
4.0 – 5.0
> 2 years
(Age + 16)/4
Age/4 + 3.5 or 3.0
Age
3.0 – 3.5*
3.0 – 4.0
3.5 – 4.5
Respiratory system
considerations
• Lung volumes = to adults on ml/kg basis
• Work of breathing = to adults on per kg basis
• Nasal resistance lower in infant
• Bronchi and small airways resistance --- Increased
• Chest wall compliance --- Increased
• Lung compliance --- decreased
• Chest wall compliance --- increased
• Diaphragm and intercostal muscles --- less tone and less efficient
• O2 consumption ----
Diaphragm & Intercostal Muscles
• Type I fibers (marathoners)
- Slow
twitch, high oxidative
- Fatigue resistant
• Type II fibers (sprinters)
- Fast
twitch, low oxidative
- Fatigue prone
- Less energy efficient
Percent Type I Fibers
• Early fatigue with ↑ work of breathing
AGE
DIAPHRAGM (%)
INTERCOSTAL (%)
Preterm
10
20
Term
25
45
1 year old
55
65
Adult
55
65
• The % of Type 1 fibers (fatigue resistant) is less in infants than
adults and increases with age.
Alveolar ventilation/FRC
Infant
3 Year Old
5 Year
Old
600
1760
1800
4200
(150 mL/kg)
(117 mL/kg)
(100 mL/kg)
(60 ml/kg)
FRC (mL)
120
490
680
2800
VA/FRC
5/1
3.5/1
2.6/1
1.5/1
VO2
mL/kg/mi
n
6-8
4-6
4-6
2-3
VA (mL)
Adult
• Blunted CO2 response, decreased Ventilatory drive (apnea)
• The response to hypoxia is to increase the RR but only for one
minutes and then become apneic.
Parameters
RR (bpm)
TV (ml/kg)
Dead space (ml/kg)
VD:VT ratio
Compliance (ml/cmH2O)
Resistance (cmH2O/L/s)
Time constant (s)
O2 consumption (ml/kg/min)
Neonate
30 -40
Adult
15
7
7-10
2.2
0.3
2.2
0.3
5
25
0.5
100
5
1.1
7
3
Cardiovascular system
considerations
• Less contractile myocardium
• Ventricles less compliant
• Limited stroke volume
• Vagal parasympathetic tone is more dominant
Renal system considerations
• Reduced RBF and glomerular filtration rate
• Tubular function is immature until 8months,
• Dehydration is poorly tolerated
• Urine output 1-2 ml/kg/hr
• Limited capacity to compensate for Volume EXCESS or Volume
DEPLETION
Hepatic system considerations
• Immature liver function with decreased function of hepatic enzymes
Glucose Management
• High glucose utilization
• Low glycogen stores
• Impaired glycogenolysis and gluconeogenesis
• D10 Water, D10 0.2% NaCl and D5 LR
• Intraoperative bolus fluid – 10ml/kg
HAEMATOLOGY
• At birth, 70-90% of the haemoglobin molecules are HbF.
• The vitamin K dependent clotting factors (II, VII, IX, X) and platelet
function are deficient in the first few months.
• Transfusion is generally recommended when 15% of the circulating
blood volume has been loss.
CENTRAL NERVOUS SYSTEM
• Blood brain barrier(BBB) poorly formed
• Thin walled & fragile cerebral vessels in preterm infant
• Neonates can appreciate pain
• At birth, the cord (conus medullaris) ends at L3/L4
Thermoregulation in Neonates
• Greater heat loss
• Less thermogenesis in premature infants
• No shivering until 1 year
• More prone to iatrogenic hypothermia
• Proportionally more substantial percentage of skin gets exposed
• General anesthesia inhibits central thermoregulation
Mechanism of heat production
• Physical activity
• Shivering
• Non shivering thermogenesis
Mechanism of heat loss
• Radiation
• Convection
• Conduction
• Evaporation
Predisposing factors for
hypothermia
• Large BSA to weight ratio
• Lack of insulating fat
• Impaired thermoregulatory ability
• Prematurity – dermis is not well keratinized
Hypothermia and its effect
• Delayed awakening
• Cardia irritability
• Respiratory depression
• Altered drug metabolism
• Coagulopathy
• Shivering – increase O2 consumption by 200-400%
• Shift ODC to the left
Pharmacologic consideration
• Total body water content increased (70-75%)
• Hepatic biotransformation immature
• Protein binding decreased
• Neuromuscular junction immature
• Muscle mass in neonates smaller
PSYCHOLOGY
• Infants less than 6 months of age are not usually upset by separation
from their parents.
• Children up to 4 years of age are upset by the separation from their
parents, unfamiliar people and surroundings.
• School age children are more upset by the surgical procedure, its
mutilating effects and the possibility of pain.
• Adolescents fear narcosis and pain, the loss of control and the
possibility of not being able to cope with the illness.
• Parental anxiety is readily perceived and reacted on by the child.
Age-Specific Anxieties of Pediatric Patients
0-6 months
•
Maximum stress for parent
6 months–4 years
•
•
Minimum stress for infants—not old enough to be frightened of strangers
Maximum fear of separation
•
Not able to understand processes and explanations
•
Significant postoperative emotional upset and behavior regression
•
Begins to have magical thinking
•
•
Cognitive development and increased temper tantrums
Begins to understand processes and explanations
•
Fear of separation remains
•
•
Concerned about body integrity
Tolerates separation well
•
Understands processes and explanations
•
May interpret everything literally
•
•
May fear waking up during surgery or not waking up at all
Independent
•
Issues regarding self-esteem and body image
•
Developing sexual characteristics and fear loss of dignity
•
Fear of unknown
4–8 years
8 years–adolescence
Adolescence
53