Transcript NEONATAL AND PAEDIATRIC ANAESTHESIA

ANAESTHETIC IMPLICATIONS
IN PEDIATRIC PATIENTS
Dr Vishawjeet Singh
Moderator Dr Jyoti Pathania








PREOPERATIVE PREPARATION
A– In addition to routine pre- anaesthetic
evaluation, the following points should be
stressed:
1- gestational age at birth- extent of
prematurity.
2- congenital anomalies
3- assessment of airway (cleft lip, micrognathia )
4- severity of coexistent disease-eg sepsis , resp.
failure.
5- degree of birth asphyxia, apneic spells.






B- CHILD--Psychological preparation is very important.
1- Children over 2-6 years are over 5 times more likely to
have significant preoperative anxiety.
2- parental anxieties concerning the surgical procedures
may be profound and can be transmitted to the child.
3- anaesthesiologist should formulate the plan for
smooth induction, explain the possibilities regarding
induction and help soothe the family members.
4- chidren are principally worried about pain and
separation from parents.


Presurgical prep. programmes such as
brochures, videos or tour can be helpful.
Reassurances to parent and children is
helpful.
In hospitals with appropriate facilities,
separation anxiety can be avoided by
inviting a parent to accompany the child at
induction of anaesthesia.












ANAESTHETIC ASSESSMENT
Previous illness and operation
H/o allergy
h/o apnoeic spells- more likely to develop apnoea following anaesthesia and should
not be accepted for day care procedres until they are atleast 50 wks gestation.
WEIGHT- influence the selection of anaesthetic eqipments.
Upto 12 yrs wt= (age + 3) 5/2 or age x 2 +9
h/o respiratory tract infections
URTI– H/O RTI within 4 wks of operation , or who have symtoms of URTI
preoperatively are at increased risk of respiratory complications such as --laryngospasm
bronchospasm
atelectasis
hypoxemia
it is usual to postpone elective srgery for 4-6 wks, which may not be always
practical.


URTI- If decision is taken to proceed with
the surgery endotracheal tube should be
used to control the airways.
Postoperatively the pt needs supplemental
oxygen and careful monitoring.











Examination
Head and neck– for
loose deciduous teeth
signs of potentially difficult
intubation
limited mouth opening
micrognathia
large tongue
noisey breathing
A precordial murmur , circulatory instability or cyanosis point to a CHD in
neonate.
Preoperative cough, fever, malaise and audible chest signs suggests lower
respiratory tract infections. Elective anaesthesia should be postponed for 46 wks.








INVESTIGATIONS
Neonates scheduled for elective minor surgery--- CBC
S. Glucose
Neonates with chronic illness and congenital defects– CBC, glucose,
albumin, clotting profile, platelet count.
In a healthy child scheduled for minor surgery – no investigations
needed.
Hb estimation– in pts of chronic diseases , hemoglobinopathies,
anaemia.
Hb and cross matching- if significant blood loss anticipated.
Other investigations should be indicated only when clinically
indicated.
PREOPERATIVE FASTING

milk
clear fluids
 <6mths
4
2
 6-36mths
6
3
 >36 mths
8
3
 Preoperative fasting times for different types of liquid
and solids
clear
breast
cow/formula solid
milk
milk
< 3 mths 2
4
4
6
> 3 mths 2
4
6
6




Infants and young children become dehydrated
easily than adults.
Preoperative fasting is required to minimize
residual gastric volume at induction of
anaesthesia and reduce the risk of pulmonary
aspiration of gastric contents.
Gastric emptying time with breast milk and cow
milk is more and thus more chances of
aspiration.







PREMEDICATION
No premedication is required for < 6 mths
The need for premedication should be
individualized according tounderlying medical condition
length of surgery
desired induction of anaesthesia
psychological make up of child and family.


















Drugs for premedication
MIDAZOLAMOral
0.5 - 0.75 mg/kg
Nasal 0.2 - 0.3 mg/kg
Rectal 0.4 – 0.5 mg/kg
Im
0.1 – 0.15 mg/kg
It takes 20 minutes for oral midazolam to be effectve.
KETAMINE—
IM
2 mg/kg- in highly uncooperative pts
Oral6 mg/kg
Nasal 3 mg/kg
ORAL TRANSMUCOSAL FENTANYL CITRATE
(OTFC)
15 -20 mg/kg
onset
20 – 30 min
duration 30 min
disadvantages
nausea, vomiting, pruritis, occasional desaturation.
advantages
decreases intra and post operatine analgesic requirements.








SUFENTANIL
Nasal
1.5 – 3 microgm/kg
Onset
10 min
Adv
dec analgesic requireements
early discharge from hospital
Disadv
burning sensation in the nose
dec in chest wall compliance
and oxygen saturation.



H2 BLOCKERS
To decrease the potential for aspiration of gastric
contents.
ANTICHOLINERGICS
glycopyrrolate 5mic/kg
atropine
20 mic/ kg
-- lessen incidence of bradycardia
-- reduces incidence of hypotension during
induction in neonates and infants
-- prevent accumulation of secretions for pts wiyh URTI,
and those given ketamine.








INDUCTION OF ANAESTHESIA
Choice of agent and technique must be based
on the needs of the individual patient.
Method/ technique of induction is determined by
-- medical condition of the patient
-- surgical procedure
-- level of anxiety of the child
-- whether able to cooperate, communicate.
-- presence or absence of full stomach.












A- INHALATION INDUCTION
-Reduced requirement
-incd incidence of bradycardia, hypotension and cardiac arrest To attenuate this, HR
maintained and preload optimized.
Iv atropine 0.02 mg/kg.
BSS or albumin 10-20ml/kg before induction
**Most dangerous time during inhalation induction as the child loses consciousnessdepress the heart
So once anesthesia is induced, dec halothane or sevoflurane conc. till iv line is
secured
Don’t proceed to deeper planes of anesthesia without iv line in place.
2nd most dangerous point- immediately after tracheal intubation If vaporizer
not closed before laryngoscopy-overdose of inhaled anesthetics
DISCONTINUE ALL ANESTHETICS UNTIL LARYNGOSCOPY AND ET INTUBATION
ACCOMPLISHED





TECHNIQUES
NEONATES AND INFANTS
holding the end of anaesthesia circuit in a cupped hand
over the infants face, the other hand can adjust the conc
of anaesthetic .
Allowing the neonate or infant to suck on a rubber
nipple or on a finger generally prevents crying during
induction.
As the infant loses consciousness, the anaesthesia mask
is added to improve delivery and to decrease operating
room pollution.












PEDIATRIC PATIENTS
1- BLOW UP THE BALLON
2- HYPNOTIC SUGGESTIONS
anesthesia mask- aeroplane pilots mask
smell of halothane- aviation fuel
The use of constant conversation and 0.25 – 0.5% increase in inspired concentration
for 3 – 4 breaths.
If child holds breath, avoid assisted respiration as it can cause laryngospasm,
coughing.
3- FLAVOURED MASK
4- SINGLE BREATH TECHNIQUES
Child is asked to take a full inspiration followed by a full expiration. Placement of
mask at the end of expiration, another full inspiration held as long as possible and
then normal breathing.
Prior to inductioin– circuit is filled with 55 halothane in 60% n2o.
Takes < 1 min for induction









HALOTHANE
Standard agent
Sweat, non pungent, allows smooth induction and
maintenance.
early onset and recovery.
Lower MAC in neonates d/t
A- immaturity of CNS.
B- attenuation of pain response d/t high levels of plasma
peptides.
Higher MAC in infants d/t increase in brain water
content.
In view of profound cvs effects of halothane in infants an
incremental technique of induction is employed.



Incremental techniqueFollowing the administration of 70% N2O
in oxygen, halothane concentration is
increased in 0.5% increments every 3-5
breaths.
Consciousness is usually lost after 1-2
min. this incremental technique may
occasionally be associated with An
exaggerated excitement phase.







ISOFLURANE
Less myocardial depressant
Preservation of heart rate
Greater reduction of CMRO2
Noxious smell and thus greater incidence of
airway related problems.
DESFLURANE
Unsuitable for inhalational induction as it has a
pungent etheral odour.




SEVOFLURANE
DOC for inhalational induction in many centres becoz of
its- --minimal pungency
---Relatively low BG solubility- rapid induction and
recovery.
A combinatioin of N20 70% in oxygen is given initially to
obtund the child. At this stage, 8% sevoflurane can be
introduced without any reaction from the patient and
unconsciousness will be produced after 4-6 breaths. In
addition to increasing the speed of induction, the use of
8% sevoflurane results in less excitation than an
incremental technique.




Disadvantages sevoflurane
relatively higher rate of metabolism
fluoride ion
compound A .




NITROUS OXIDE
Sweet smelling, non irritant, non inflammable.
Occasionally premature and sick neonates may
not tolerate cvs effects of nitrous in which case
air may be substituted as a carrier gas for
oxygen.
Main contraindication is h/o air pockets within
the body and the need for high inspired oxygen
concentration.







INTRAVENOUS INDUCTION
Important when induction with mask is contraindicated- full
stomach, reflux esophagitis
i/v access.
Cannulation of tiny pediatric patient can be difficult.
Use of EMLA crème.
All air bubbles should be removed from the i/v line since high
incidence of patent foramen ovale increases the risk of paradoxical
air embolism.
In emergency situations where iv access is impossible fluids can be
effectively infused through an18 G needle inserted into the
medullary sinusoids within the tibial bone. This intraosseous infusion
can be used for all medications normally given iv with rapid result.










1- THIOPENTONE SODIUM
Lower dose in neonates than in infants
Neonates- 4-5 mg/kg
Infants - 7-8 mg/kg
decreased dosage in neonates is due to
-- immature brain
-- decreased plasma protein binding
-- more permeable BBB.
INCREASED REQUIREMENT in infants d/t
increased cardiac output as this would be expected to reduce the
first pass concentration of thiopentone arriving at the brain.






Propofol
Dose required is higher in children
< 2 yrs – 2.9 mg/kg
6-12 yrs – 2.2 mg/kg
KETAMINE
AS an induction agent in neonates especially
those with cyanotic heart disease.








RECTAL INDUCTION
Child falls asleep in parents arms
Methohexital- 10% 25- 30 mg / kg
Induction within 8-10 minutes.
THIOPENTONE
30mg/kg
Ketamine 10 mg/kg
Midfazolam 1mg/kg max 20 mg






INTRAMUSCULAR INDUCTION
Adv- reliability
Disadv- painful
Methohexital – 10 mg/kg
Ketamine
-- 1 – 10 mg/kg
Midazolam -- 0.1 mg/ kg





RAPID SEQUENCE INDUCTION WITH
CRICOID PRESURE
In full stomach patients
Rapid desaturationmay occur in child
because- oxygen consumption high
child may refuse
preoxygenation
Atropine 0.02 mg/kg is given iv to prevent
reflux induced/ sch induced bradycardia.





Prep. of intubating equipment and suction
Preoxygenation of lungs
Rapid induction using STP, propofol or
ketamine
Application of cricoid pressure
Rapid onset of paralysis with sch, roc








MUSCLE RELAXANTS
SUCCINYL CHOLINE
1-- Highly water soluble, therefore increased dose requirement in
paediatric patients.
2 – effective when given intramuscular.
Infants – 5 mg/kg
children 4 mg/kg
onset 3-4 min
duration of relaxation 20 min
In an emergency situation scholine can be given intralingually. 2
mg/ kg in midline to avoid hematoma formation.


3– Children are more susceptible than adults to
cardiac arrhythmias, hyperkalemia, and
malignant hyperthermia after Sch administration
due to underlying unrecognized muscle
dystrophy. So it should be best avoided for
routine elective surgery in children.
4– atropine should be given just prior to the first
dose of scholine in all children including
teenagers.






NON DEPOLARIZING MUSCLE RELAXANTS
Immaturity of neuromuscular junctiontends to increase
senstivity.
Disproportionately large extracellular compartment
results in dilution of drug.
Greater volume of distribution in neonates result
inslower rate of excretion and prolongation of effect.
Drugs such as vecuronium which has hepatic metabolism
has increased duration of effect.
Hoffman degradation of atracurium makes it useful but
histamine release can be a problem.








MIVACURIUM
0.2 – 0.3 mg/kg dose causes adequate relaxation within
2 minutes and thus is ideal for constant infusion.
ROCURONIUM
0.6 mg/kg for routine induction
0.9 – 1.2 mg/kg- rapid sequence induction but prolonged
duration 60-90 min should be expected.
It offers the advantage that it could be given
intramuscularly in deltoid. It produces intubating
conditions in 3 – 4 minutes.
im- 1mg/kg infants
1.8 mg/kg children > 1 yr


Because of the extreme variability in
response, the doses of long acting muscle
relaxants should be titrated carefully
starting from half to third of the usual
dose.
The effect of the incremental doses of ms
relaxants should be monitored with a
peripheral nerve stimulator.


ANTAGONISM OF MS RELAXANTS
IT is recommended in all neonates and
infants even if they have recovered
clinically becoz any increase in the work of
breathing may cause fatigue and
respiratory failure. Useful signs of reversal
are the ability of infant to lift the legs and
arms.
PEDIATRIC AIRWAY MANAGEMENT




INTUBATION
Following inhalational induction, N20 and
vaporizers should be discontinued prior to
intubation so that that the lungs contain high
inspiratory concentration of oxygen to combat
apnoea.
Correct head position
Application of the external pressure at the level
of cricoid cartilage to push the larynx into view.




LARYNGOSCOPE BLADE
INFANTS- flat blades are more suitable as it
flattens out the curvature of the epiglottis and
can be used to lift it forward to expose the
larynx.
> 1 yr– medium sized curved badeswith the tip
placed in the vallecula.
Gentle insertion, avoid trapping the lips between
teeth and blade . Not to lever on upper tooth.








Tube size
Uncuffed tubes < 8 yrs of age.
Decreased incidence of post intubation croup
Provide a leak tominimize the risk of accidental
barotauma. Allow a leak when 20- 30 cm of
water pressure is applied.
Size- < 6yrs – age/3 +3.5
>6 yrs – age/4 + 4.5
neonate 3 kg – 3 mmid
< 3kg – 2.5 mmid






Tube length
Length of the tube should be such that
the tip of the tube lies in midtrachea while
2-3 cm protrudes from the mouth.
Length in cm = ID X 3
> 2 yr = age/2 + 13
Neonate = 10 cm
1 yr = 12 cm
ANESTHESIA CIRCUITS FOR
PEDIATRICS







A- dead space should be minimal
B- weight and size be suitable
C- no valves to cause undue obstruction
D- humidified gases be used
E- reservoir bag should be smaller to monitor
respiratory movements.
F- facemask must fit well to contour of face.
G- work of breathing should be less while
preventing rebreathing.







NON REBREATHING CIRCUITS
1- provide minimal WOB becoz they have no valves to be opened up
by patients respiratory efforts.
2- rate of induction is rapid becoz
- volume of non rebreathing circuit is less
- no equilibrium with CO2 absorber is required
- anaesthetic gases are delivered immediately in the airway.
3- as the volume of nonrebreathing circuit is small as compared to
that of circle system,the compression and compliance volumes are
significantly less. This improves the ability to observe respiratory
efforts as reflected by movement of anaesthesia bag as well as the
ability to estimate pulmonary compliance.


T – piece system
Original T- piece ( Ayres) system consists
of light metal T tube with a main lumen of
1cm diameter and of smaller side tube at
right angle to the main lumen through
which anaesthetic gas mixture was
introduced. A length of rubber tubing
attached to open end of T piece act as
reservoir for anaesthetic gases.








Jackson Rees modification
Attached open tailed bag to the reservoir tube in
order to facilitate controlled ventilation.
ADV- simplicity
convenience
compact size
T Piece system rely on adequate FGF to
eliminate CO2
During spontaneous vent- FGF > 2 MV
Controlled vent FGF = MV









CIRCLE SYSTEM
Consists of –
afferent and efferent breathing tubes
Reservoir bag
Chemical absorber
One way flow d/t unidirectional valves
ADVEconomical use of anaesthetic gases
Conservation of heat and humidity

Provided ventilation is controlled in
neonates and either controlled or assisted
in infants , a standard adult circle system
fitted with low dead space connectors , a
small bore tubing and a reduced capacity
reservoir bag is suitable for maintenance
of anaesthesia for pts of all ages.
MAINTENANCE OF ANAESTHESIA






The goalsProvision for adequate anesthesia and operating
conditions
Maintaining physiological hemostasis
Adequate fluid replacement
Infants are poor candidates for anaesthesia with
spontaneous ventilation becoz of poor pulmonary
mechanics and increased susceptibility to cardiovascular
depressant effects of volatile anaesthetic agents.
Combination of tracheal intubation and balanced
anaesthesia with full dose of muscle relaxants ,
controlled ventilation, minimum concentration of volatile
anaesthetics and reduced dose of opioids is optimum.
MONITORING












Pulse – temporal/ radial artery easily accessible.
Precordial/ esophageal stethoscope auscu;ltation
ECG monitoring
Respiratory monitoring by visual movements of chest wall
Pulse oximetry
ETCo2 for assessment of ventilation and confirmation of ETT
placement and early warning of MH.
Temperature monitoring
Urine output
Fluids
Glucose monitoring
NIBP monitoring
Invasive monitoring
POST OPERATIVE CARE






Attention to the airways
Provision of oxygen therapy
Monitoring of pulse, respiration and blood
pressure
Completion of post anaesthetic recovery charts
Recovery nurses should be trained to detect
early changes in respiration and circulation and
should be able to initiate treatment while the
anaesthesiologist is summoned.
Once the child is awake , one of the patients
parent can come in the recovery.
PROBLEMS DURING RECOVERY










-- Hypoxemia – oxygen administered routinely to
all pts
-- Post operative apnea
-- Nausea and vomiting –
perinorm-0.15 -0.25
emeset- 0.05- 0.1 mg/kg
-- Post intubation croup
-- Post operative pain relieforal pcm= 15 mg/kg
0.5 mg/ kg
-- Postoperative fluids

Thanks