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BY
DR.HISHAM AHMED,M.D.
CONSULTANT PEDIATRIC SURGERY
INTRODUCTION
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Pediatric patients include neonates (less than 30 days of age),
infants (1-12 months of age), and children (1-12 years of age)
who are not merely small adults.
Their successful and safe surgical and anaesthetic
management depends on an appreciation and clear
understanding of the physiologic, anatomic, pharmacologic
and psychologic differences between each group and adults.
The smaller size, immature organ systems, and differing
volume capacities present unique challenges toward
perioperative management. .
Key areas of concern in the newborn include:
1- Respiratory Function
2- Cardio-circulatory Function
3- Fluid and Electrolyte Regulation
4- Thermal Regulation
5- Metabolic Problems
Key areas of concern in the newborn include:
6- Nutrition
7- Stress Response to Surgery
8- Infection in the newborns
9-Control of pain
10- Rate of deterioration
1-Respiratory Function
► A- Adequate ventilation in an infant may be impaired by;
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Immaturity of the pulmonary tissues
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Tiny air passages that are easily occluded by edema or
secretions.
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Narrow nasal passages
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Small pharynx
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High larynx (C3)
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Large tongue
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Long Mobile epiglottis
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Short trachea and neck
1-Respiratory Function
► B- Increase Oxygen demand required for their
relatively high metabolic rate;
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Oxygen consumption in the neonate is 6 ml/Kg/min versus
3 ml/Kg/min in the adult.
The process of pulmonary alveolar maturation is not
complete until 8-10 years of age.
The number of saccules and primitive alveoli in the lung
of a neonate is only 8% of the number of the alveoli in an
adult.
Alveolar ventilation in a neonate is twice that of the
adult ( 100-150 ml/Kg/min versus 60 ml/Kg/min).
1-Respiratory Function
►C- Normal pediatric respiratory rate for infants,
newborn, toddlers, and children
Groups of children
Their ages
Normal respiratory
rate
Newborns and infants
Up to 6 months old
30-60 breaths/min
Infants
6-12 months old
24-30 breaths/min
Toddlers and
children
1-5 years old
20-30 breaths/min
Children
6-12 years
12-20 breaths/min
2-Cardio-circulatory Function
A satisfactory circulating blood volume is the most important
factor in determining whether an operation can be undertaken
safely, and in the absence of cardiac failure.
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The blood volume of a newborn infant is
approximately 10% of the total body
weight.
High hematocrit in the first few days of
life (>50%) .
A minimal deficit of 25% can lead to acute
hypovolemic shock.
2-Cardio-circulatory Function
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A single surgical sponge may absorb as much as
20 ml of blood ( a few saturated sponges may prove
sufficient to precipitate shock).
Transfusion of blood is given for losses >10% of the
blood volume. A transfusion of 10 ml/Kg is
approximately equivalent to the administration of
a single unit of whole blood to a 70 Kg adult.
An infant can tolerate rapid infusion of 20-25
ml/Kg of whole blood or plasma without ill effect.
* Normal ranges of blood pressure in children
Age
Normal range
SBP (mmHg)
Normal range
DBP (mmHg)
Premature
55-75
35-45
0-3 months
65-85
45-55
3-6 months
70-90
50-65
6-12 months
80-100
55-65
1-3 years
90-105
55-70
3-6 years
95-110
60-75
6-12 years
100-120
60-75
Over age 12
110-135
65-85
Normal heart rates (Resting) in children
Age
Normal range (resting)
Premature
120-170 b/m
0-3 months
100-150 b/m
3-6 months
90-120 b/m
6-12 months
80-120 b/m
1-3 years
70-110 b/m
3-6 years
65-110 b/m
6-12 years
60-90 b/m
Over age 12y
55-85 b/m
3-Fluid and Electrolyte Regulation
In managing the pediatric surgical patient, an understanding of fluid and
electrolyte balance is critical, as the margin between dehydration and fluid
overload is small.
• The total body water (TBW) of a newborn is 75-80% at term
gestation, decreased by 4-5% during the first week of life.
• The glomerular filtration rate (GFR) of the newborn is 25%
that of the adult.
• The GFR rapidly rises during the first week of life and then
slowly increases to adult levels by 2 years of age.
3-Fluid and Electrolyte Regulation
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The immaturity of the newborn kidney contribute
to the inability to concentrate and conserve fluid
and electrolyte, and so rapid development of
respiratory and metabolic acidosis or alkalosis.
The normal urinary output in adequately hydrated
infant should approximate 1-2 ml/kg/hr.
♠ What is the maintenance IV fluid for children?
D5 ¼ NS + 20 mEq KCL
♠ How are maintenance fluid rates calculated in children?
4,2,1 per hour
*4 cc/kg for the first 10 kg of Body weight
*2 cc/kg for the second 10 kg of body weight
*1 cc/kg for every kilogram over the first 20 kg.
4-Thermal Regulation
Newborn infants are potentially thermolabile as a
consequence of;
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Increased body surface area relative to
weight.
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Thinner layer of insulating S.C fat.
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Immature thermal regulatory mechanisms.
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Incomplete myelination of the heat
regulating center in the hypothalamus
4-Thermal Regulation
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Inadequate vasoconstriction of cutaneous
vessels in response to cold.
Minimal shivering and sweating mechanisms.
All premature babies and most neonates will require incubators or
at least wrapping of limbs and body with cotton wool to minimize heat loss.
4-Thermal Regulation
Normal Temperatures by Age and Method
Age
Oral
Rectal
Axillary
(Armpit)
Ear
0-2 years
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97.9-100.4
94.5-99.1
97.5-100.4
3-10 years
95.9-99.5
97.9-100.4
96.6-98.0
97.0-100.0
Over age
11
97.6-99.6
98.6-100.6
95.3-98.4
96.6-99.7
To convert to Celsius (F-32)x5/9=c
5-Metabolic Regulation
There are 3 major potential metabolic abnormalities
that can be occurred in a neonate.
1-Hypoglycaemia
3-Hyperbilirubinemia
2-Hypocalcaemia
5-Metabolic Problems
►1-Hypoglycaemia;
It’s common and dangerous
complications in the newborn
stressed by surgical trauma or
disease .
It’s due to
♠ Deficiency of glycogen stores
♠ Impaired gluconeogenesis
♠ Difficulties with insulin regulation
N.B; The normal range of glucose
production in a newborn is
about 5-8 mg/kg/min.
►2-Hypocalcaemia;
(especially in premature infants)
Overall, one of the most common
causes of hypocalcemia is renal
failure because of inadequate
1-hydroxylation of 25-hydroxyvitamin D.
Other causes of hypocalcaemia:
♠ Prematurity
♠ Birth asphyxia
♠ Exogenous phosphate load
♠ Hypoparathyroidism
♠ Abnormal vitamin D production
♠ Intrauterine growth retardation
5-Metabolic Problems
►3-Hyperbilirubinaemia; (Neonatal Jaundice)
♦ It is virtually a normal physiological occurrence in almost all
newborn especially in the first 3-7 days.
♦ It is the result of accumulation of unconjugated bilirubin in
healthy neonates.
♦ In white and black infants the peak level of bilirubin is ~6 mg/dl at 72
hours of age. In Asian infants the bilirubin level peaks later(3-5days)
at a higher level ~ 12 mg/dl.
♦ Bilirubin is neurotoxic and can cause death in newborns or Kernicterus
which is a bilirubin staining of the basal ganglia, thalamus, cerebellum,
hippocampus, and cranial nerve nuclei leading to long-term sequelae
in children.
5-Metabolic Problems
Neonatal physiologic jaundice results from simultaneous
occurrence of the following 2 phenomena;
♥ Increased bilirubin production because of increased
breakdown of fetal erythrocytes.
♥ Hepatic excretory capacity is low both because of low
concentrations of the binding protein and low activity of
glucuronyl transferase enzyme
Jaundice in infants that persists longer than 2 weeks should not be considered
Physiologic, especially if the predominant fraction is conjugated bilirubin.
6-Nutrition
♣ Because of limited caloric reserves and the high
demands due to rapid growth and maturation,
maintenance of adequate nutritional support is of
paramount important.
♣ The best feed for infant is fresh maternal breast milk,
if not possible, parentral feeding should be started,
using solutions of amino acids (Vamin),fats (Intralipid
10% or 20%) and carbohydrates ( Dextrose) with
electrolytes, vitamins and trace elements via a central
venous or peripheral venous line.
6-Nutrition
Caloric requirements by age for the following patients
• Premature infants
80 kcal/kg/day
• Children < 1 year
100 kcal/kg/day (90-120)
● Children ages 1-7 years
85 kcal/kg/day (75-90)
● Children ages 7-12 years
70 kcal/kg/day (60-75)
● Children ages 12-18 years
40 kcal/kg/day (30-60)
7- Stress Response to Surgery
♣ The endocrine and metabolic response to surgical stress
in newborn is characterized by catabolic metabolism.
♣ An initial elevation in catecholamines, cortisol and
endorphins upon stimulation by noxious stimuli occurs.
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Responsiveness during the first week of life is
diminished , due to immaturity of the adrenal gland.
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During surgical stress newborn release glucose, fatty
acids, ketone bodies and amino acids necessary to meet
body energy needs in time of increased metabolic
demands.
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Early post-operative parenteral nutrition can result in
significant rate of weight gain due to solid tissue and
water accumulation.
7- Stress Response to Surgery
A-Hormonal
Response
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ACTH
Endorphins
Growth hormone
Vasopressin (ADH)
Prolactin
Catecholamine
Aldosterone
Cortisol
RAS activation
B-Metabolic
Response
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Temperature
O2 consumption
CO2 production
Urinary potassium loss
Blood glucose level
Salt and water retention
Mobilization of fatty acids.
Insulin resistance.
7- Stress Response to Surgery
Phases of the metabolic response;
1-Catabolic phase(3-10 days)
a-Ebb;
is the initial phase occurring within the 1st 24 hours
where a decrease in metabolic rate is seen
b-Flow; is the next phase which is associated with an increase
in metabolic rate.
2-Anabolic Phase ( 10-60 days)
Characterized by replacement of lost tissues
7-Stress Response to Surgery
Factors contributing to a prolonged catabolic response
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Degree of neuro-endocrinal maturation
Duration of operation
General condition of the patient
Amount of blood loss
Type of surgical procedure
Type of pathology
Extent of surgical trauma
Associated conditions ( hypothermia, prematurity, etc.).
8- Infection in Newborn
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In stable newborn infants the intra-cellular
phagocytosis-killing of bacteria is normal, but with
the added stress of sepsis or operation there is a
significant decrease in bactericidal activity as a
result of the immunosuppressive effect of operation
and anaesthesia.
Gram +ve ( staphylococcus aureus or albus) and gram
–ve (E-coli) sepsis account for the major and most
serious infections, that may lead to severe acidosis,
hypothermia and circulatory collapse in late cases.
Broad spectrum antibiotics are indicated when
complex surgical procedures are performed in
neonates
9- Pain Control
♠ The past 20 years have seen many changes in the understanding
and treatment of acute pain in infants and children.
♠ The first step was to disprove the previously held
misconceptions that neonates, infants and children did not feel
or react to pain like adults.
♠ This belief was based on the misconception of the immaturity of
the CNS of infants made them less likely to perceive pain.
♠ This theory compounded by fears of addiction and adverse
effects from opioids, resulted in the inadequate treatment of
pain.
9- Pain Control
♠
Recent studies have shown that infants and children experience
a severity of postoperative pain similar to adults and that
even premature infants demonstrate alterations in heart rate,
blood pressure, and oxygen saturation in response to painful
stimuli.
♠ Considerations in the treatment of acute pain includes;
* The severity of pain
* The setting in which it is treated
(inpatient Vs outpatient)
♠ One approach is to use a three step ladder, initially described
by the World Health Organization for the treatment of cancer
related pain.
9-Pain Control
The World Health Organization Ladder for Pain Control
♣ Mild Pain
1- NSAIDs
-2-Acetaminophen
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♥ Moderate Pain
1 - NSAIDs or acetaminophen with a weak opioid ( codeine)
2- Intravenous opioid with addition of fixed interval NSAIDs or
acetaminophen either;
a- IV opioid by (PCA)
b- Continuous infusion of opioid with as needed rescue doses
of opioid.
c- Fixed interval dosing of opioid
3- Regional anesthetic techniques
♠ Severe Pain ( continue use of NSAIDs or acetaminophen)
1- IV opioid by PCA
2- Regional anesthetic technique
9- Pain Control
10-Rate of Deterioration
♥ Newborns deteriorates rapidly than
adults.
♥ A child can become dehydrated from
gastroenteritis to the extent of
peripheral circulatory failure in a day.