PAEDIATRIC
ANAESTHESIA
GUIDE
DEPARTMENT OF ANAESTHETICS
ROYAL ABERDEEN CHILDREN'S
HOSPITAL
A GUIDE TO PAEDIATRIC ANAESTHESIA
INTRODUCTION 3
& ORIENTATION INFORMATION
AIRWAY 6
tracheal tubes
laryngeal mask airways
upper airway obstruction
VENTILATION 8
circuit flows
CIRCULATION 9
fluid & electrolyte management
intra-operative fluid replacement
replacement of measured losses
fluid therapy in burns care
inotropic support & vasoactive drugs
PRE-OPERATIVE PREPARATION & PREMEDICATION 12
preoperative fasting guidelines
premedication
heart murmurs, steroid cover for surgery
latex allergy, vaccinations and anaesthesia
parents accompanying children to theatre
INTRAOPERATIVE MANAGEMENT 16
useful drugs
local and regional anaesthesia
management of severe laryngospasm
POSTOPERATIVE CARE 18
postoperative analgesia
management of opioid-induced respiratory depression
FURTHER READING 19
Appendix: RACH floor plan, drug aide-memoire, clinical emergencies,
2000 Area codes
INTRODUCTION
This guide is directed towards anaesthetists new to working in Aberdeen and
provides practical details on working in the children’s hospital.
This is also intended as a guide to those who are called upon to anaesthetise
children on an occasional basis. The information contained is by no means
comprehensive and readers are advised to refer to standard textbooks on
paediatric anaesthesia for further material.
Trainees must discuss with the on-call Paediatric anaesthetist any child under
3 years of age requiring anaesthesia. Likewise, the on-call Paediatric
anaesthetist must be informed of any seriously ill child requiring an
anaesthetic, regardless of age. If in doubt, we would much rather know than
not know.
Consultant Paediatric Anaesthetists
Bleep No.
Paediatric Anaesthetist
Office extension
G. Byers
2474 50379
Home No.
Mobile / Pager No.
A. Campbell
2798 50441
G. Johnston
2776 50440
(Head of Service)
M. Bloch
A. Sheikh
2399 51758
G. Wilson
2586.
(Lead clinician HDU)
51759
51757
A sixth consultant has been appointed recently (Dr M Bloch).
Emergency paediatric anaesthetic consultant cover is provided 24/7.
Please check the anaesthetic department rota for the day-time emergency
consultant, or call theatre RACH (50118).
After hours emergency cases are routed through the 1st on call anaesthetist.
Switchboard (52881) carry up to date duty rotas.
2000 calls All consultant paediatric anaesthetists bleeps are activated by
the paediatric group emergency call (appendix). However the 1st on call
trainee anaesthetist is not, and must be requested separately via
switchboard.
The new Royal Aberdeen Children’s Hospital
Patients were transferred from the old RACH on 25.1.04
The new hospital is linked to ARI by a link corridor.
The corridor is open to the public between 06:00 and 20:00, each day.
Otherwise access is by a proximity reader on one’s ID badge.
All clinical areas are accessed by proximity readers, therefore please ensure
your badge conforms.
The link corridor starts at lower ground floor level ARI (next to dining room)
and reaches RACH at 1st floor level, next to theatre.
Please note emergency access stairway at RACH end to resuscitation room
A&E
The main hospital entrance is open from 06:00 to 20:00 each day. Out with
these times access to the hospital is via A&E (locked after 22:00).
Theatres RACH
The theatre suite comprises three theatres, an eight bedded recovery area,
and an adjacent outpatient GA dental unit.
Theatre manager is Mrs K Coutts.
Theatre A – ENT, Orthopaedics, Max/Fax. Plastics. Sister Joyce Ross
Theatre B – Emergency work Sister Kathy Coutts
Theatre C – General Surgery, Eyes, Endosocopy. Sister Diane Rayner
Dental Anaesthetic Unit Sister Tracey Shanks
Senior ODA’s: Mr John Baxter, Mr Paddy Creelie
Surgical operating lists can be obtained from the recovery room RACH
High Dependency Unit
Adjacent to theatre, this is a multi-disciplinary 6-bedded unit. The unit
provides level 1 care, eg post op patients with airway problems, epidurals,
morphine infusions, and patients with burns, respiratory, cardiac, oncology,
metabolic, and neurological problems.
Paediatric patients requiring intensive care are transferred to the nearest
appropriate PICU. Usually Edinburgh or Glasgow, when a retrieval team will be
requested. HDU is equipped to provide facilitates for resuscitation,
stabilisation, monitoring and ventilation of patients prior to transfer.
Instructions for PICU transfer are available in HDU, however all decisions
regarding transfer are made at consultant level.
Other wards See attached floor plan of hospital
Miscellaneous telephone numbers
RACH Theatre & Bleep 50118/50128 Bleep 3618
RACH Recovery 50123
RACH High Dependency Unit 50208/50209
RACH Surgical ward 50394/52398
RACH Medical ward 50380/50116
RACH Day case unit 550643/59294
RACH A&E (recep) 52041
RACH A&E (resus) 50215
ARI Anaesthetic Dept. 53144/53237
AMH Neonatal Unit 52602
CT scan 52177
MRI scan 54440/54441
X-Ray 50218
AIRWAY
Tracheal Tubes
Estimating the appropriate size of an uncuffed endotracheal tube is carried
out as follows:
Internal diameter (mm) = (Age/4) + 4.5
Length (cm) = (Age/2) +12 for an oral tube
Length (cm) = (Age/2) + 15 for a nasal tube
N.B. Uncuffed tubes should be used for all children under ten years of age
to avoid subglottic oedema.
If however you wish to use a cuffed tube the formula is Age / 4 + 3 (mm)
Age
Typical
Weight
(kg)
ETT Bore
(mm)
Length
Length
ORAL (cm)
NASAL
(cm)
Minute
Volume
(L/min)
Max size
suction
catheter
Prem
2
2.5
8
9.5
1.8
5
New-born
3
3-3.5
9.5
11.5
1.8
5
2/12
4.5
3.5
11
12.5
2.5
6
1 year
10
4
12
14
2.8
6
18/12
12
4.5
13
15
3.0
6
2
15
4.5
14
16
3.0
8
4
17
5
15
17
3.8
8
6
21
5.5
16
19
4.2
10
8
25
6
17
20
4.2
10
10
31
7
18
21
4.5
10
12
37
7.5
20
23
5.0
12
Laryngeal mask airways
Patient Weight/Size
1 up to 5 kg neonatal
1½ 5kg - 10kg paediatric one month to one year
2 10kg - 20kg paediatric one year to five years
2½ 20kg - 35kg paediatric five years to ten years
3 35kg - 60kg paediatric more than ten years
Upper airway obstruction
The on-call Paediatric Consultant anaesthetist and ENT surgeon should always
be called for cases of severe upper airway obstruction.
Steroids improve airway patency in croup, haemangioma, lymphoma and some
mediastinal masses. They can be given orally, parenterally or by nebuliser.
Prednisolone 4 mg/kg orally, or dexamethasone 0.2-0.5 mg/kg intravenously
or intramuscularly, or budesonide 1-2 mg by nebuliser are favoured as initial
therapy with maintenance by repeated nebuliser therapy or oral prednisolone
or parenteral dexamethasone at one quarter of the initial dose every 8-12
hours for up to 48 hours. Prompt administration of steroids often pre-empts
the need for endotracheal intubation in most cases of moderate or severe
croup.
Nebulised adrenaline is also useful, 1:1000 (1 mg) standard solution of
adrenaline at a dose of 0.5 ml/kg (max 5 ml) diluted if necessary with 0.9%
saline to a total volume of 5 mls will give a dose of 2-5 mg in most cases. It
reduces mucosal oedema and acts very rapidly but when stopped may give rise
to a rebound worsening of airway obstruction. It is a useful temporising
measure. ECG monitoring is recommended although arrhythmias are seldom a
problem.
Ventilation
RACH theatres use Ohmeda Aestiva 5 anaesthetic machines with integrated
Spacelabs monitoring systems. If you are not familiar with this machine do
not use one unsupervised. The circle system and ventilator are ideally suited
for paediatric use, allowing spontaneous respiration or pressure-controlled
ventilation at low tidal volumes.
There is also an auxiliary common gas outlet situated, along with its control
lever, below the circle outlets. This allows the use of Mapleson F systems for
inhalational induction of neonates and small infants. The outlet is alarmed,
and this alarm activated by the control lever which also disables the circle
system, but not the ventilator.
Normal tidal volume = 6-10 ml/kg best achieved by manipulating the I:E ratio
so tidal volume delivery occurs at the lowest possible inflation pressure.
Ventilator rate/min
Neonate 30 - 40
6 months 25
1-5 years 20
> 5 years 16
Circuit Flows
Ayre’s T-Piece with Jackson-Rees Modification (Mapleson F)
Spontaneous breathing FGF = 2-3 times minute volume
Assisted ventilation FGF = minute volume
The end-tidal CO2 and agent analyser must be used for any ventilated patient.
CIRCULATION
Age
Weight
Surface area
(m2)
Pulse 95%
range
Mean
BP 95% range
Term
3.5 kg
0.23
95-145
40-60
3 mo
6.0 kg
0.31
110-175
45-75
6 mo
7.5 kg
0.38
110-175
50-90
1 year
10 kg
0.47
105-170
50-100
3 years
14 kg
0.61
80-140
50-100
7 years
22 kg
0.86
70-120
60-90
10 years
30 kg
1.1
60-110
60-90
12 years
38 kg
1.3
60-110
60-90
14 years
50 kg
1.5
60-100
60-95
Fluid and electrolyte management
Estimated blood volume:
Neonates 90 ml/kg
Infants 85 ml/kg
Older children 80 ml/kg
Adults 70 ml/kg
Normal fluid requirements in neonate:
Age
Fluid requirements
Day 1 of life
2 ml/kg/hr
Day 2 of life
3 ml/kg/hr
Day 3 of life
4 ml/kg/hr
Normal fluid requirements after 1st 4 days of life:
Body weight
Fluid requirement per day
(ml/kg)
Fluid requirement per hour
(ml/kg)
First 10kg
100
4
Second 10kg
50
2
Subsequent kilogram
20
1
Intra-operative fluid replacement
All maintenance fluid should contain glucose to avoid inadvertent
hypoglycaemia. Saline 0.18% / Dextrose 4% is suitable for infants and young
children.
Saline 0.45% / Dextrose 5% is more suitable for those with ongoing sodium
loss e.g. vomiting, diarrhoea, fever etc.
Neonates may require Saline 0.18% / Dextrose 10% to maintain
normoglycaemia.
Maintenance fluid should be always be given via a burette or metered pump
(e.g. Imed, Gemini) to avoid fluid overload.
When calculating fluid requirements, remember to take account of preoperative fasting period.
Replacement of measured losses
<10% replace with 0.9% Saline
10-20% replace with Human Albumin Solution (HAS)
>20% replace with blood/ HAS mixture
Blood transfusion: to increase Hb
RCC 4mls/kg/1g rise in Hb required
Fluid therapy in burns care
Children with burns of 10% or more will require intravenous fluids as part of
their burns care, in addition to their normal fluid requirement. The additional
fluid (in ml) required per day to treat the burn can be estimated using the
following formula:
Percentage burn x Weight (kg) x 4
Of this half should be given in the first 8 hours since the time of the burn.
The fluid given in Human Albumin Solution
Inotropic support & vasoactive drugs
Inotropes should only be initiated with Consultant approval. All drugs should
be administered via a central/femoral line.
For each group of drugs below, follow the formulae in the right hand column
Dopamine
3 mg/kg in 50 mls 5%dextrose
Dobutamine
Nitroglycerine (GTN)
1 ml/hr = 1 microgram/kg/min
Na Nitroprusside
Dose: 3-20 ml/hour
i.e. 3-20 micrograms/kg/min
Adrenaline
0.3 mg/kg in 50 mls
5% dextrose
Isoprenaline
1 ml/hr = 1 microgram/kg/min
Noradrenaline
Dose 1-5 ml/kg/hour
ie 0.1-0.5 micrograms/kg/min
Pre-operative Preparation and Premedication
Preoperative fasting guidelines
The revised guidelines for preoperative fasting of elective surgical cases are
as follows:
Clear fluids (not fizzy) 2 hours
Breast milk 4 hours
Solids / milk formula 6 hours
The above refer to all ages.
Chewing gum is not allowed within the 6 hour fasting period.
The fasting requirements for emergency surgery remain at the discretion of
the anaesthetist depending on individual patient factors and the nature of
the emergency.
Premedication
Pharmacological premedication is often unnecessary after a sympathetic chat
with child and parent. If iv induction is intended all children should have
EMLA cream applied to an appropriate area. If time is limited, amethocaine
gel (Ametop) is a fast acting and potent topical anaesthetic.
Oral midazolam has gained widespread use as a premedicant in children. The
dose of oral midazolam most commonly used is 0.5 mg /kg administered
approximately 45 minutes preoperatively, with a maximum dose of 15-20 mg.
The main disadvantage of oral midazolam is its bitter taste, which can be
disguised by mixing it with Ribena or orange squash.
Heart murmurs
A common dilemma for the anaesthetist is the management of the child
scheduled for elective surgery who is discovered to have a cardiac murmur on
pre-operative examination. The following offers a guide to management.
Innocent murmurs are common in children and are not usually associated with
any anatomical or physiological abnormality. However, any child under the age
of 1 year who is found to have a murmur should be referred for cardiological
assessment prior to elective surgery as a potential lesion may not have
declared itself.
A detailed history and examination of the CVS should be performed and an
ECG and CXR requested. In the absence of symptoms or signs of heart
disease the two most dangerous conditions to exclude before surgery are
hypertrophic obstructive cardiomyopathy and critical aortic stenosis. Either
of these may be asymptotic except for the murmur, and yet pose a
significant haemodynamic risk during anaesthesia and surgery. Fortunately
left ventricular hypertrophy and left axis deviation are usually present on the
ECG in both conditions and are a clue to the sinister origin of the murmur.
If a child has an early systolic soft murmur but no signs or symptoms and a
normal ECG and CXR it is reasonable to assume no haemodynamic risk to the
patient and the surgery should proceed. The vast majority of patients with a
murmur fall into this category. However, the question of antibiotic
prophylaxis must be addressed and also subsequent follow up. Because it is so
difficult to definitely exclude a small structural lesion it is probably prudent
that all these children receive antibiotic prophylaxis prior to surgery that is
likely to cause significant bacteraemia such as genito-urinary, dental, oral or
gastro-intestinal surgery (See BNF for current recommendations).
Steroid cover for surgery
On steroids at present
Hydrocortisone 1 mg/kg iv
At induction
Every 6h iv after operation
until able to take steroids
orally
Reduce to maintenance level
over next 4 days as
tolerated
Off steroids in preceding 2
months
Hydrocortisone 1 mg/kg iv
At induction
Every 6h after operation
for 24-48 hours
Review need for steroids
Off steroids for longer than
2 months
No cover but hydrocortisone
should be available
Latex allergy
Patients should be first case of the day on operating list.
Patients with a history of anaphylaxis or allergy to latex can be pretreated
with:
Methylprednisolone 1 mg/kg (maximum 50mg) 6 hrly iv
Ranitidine 1 mg/kg 8 hrly iv over 20 minutes
Chlorpheniramine 1 month -1 year 250 micrograms/kg
1-5 years 2.5-5 mg
6-12 years 5-10 mg
All 6 hourly iv slowly.
A list of all latex free products is available in theatre.
Vaccinations and Anesthesia
Children who have been vaccinated within the last 48 hours should not
undergo surgery or anaesthesia
After 48 hours, provided there has been no systemic upset, surgery can go
ahead.
10 days post-vaccination all children are safe to undergo surgery or
anaesthesia
Parents accompanying children to theatre
Elective list cases
It is normal for one parent to accompany their child if they wish, but no
pressure should be applied if the parent is unsure. However in certain
circumstances the anaesthetist may decide that it is not advisable.
Emergency and out of hours cases
Occasionally, it might be possible for one parent to accompany their child to
theatre, but this decision rests with the anaesthetist alone. There are many
reasons as to why it is not possible to have a parent present, especially if a
"rapid sequence induction" is indicated. There should be an information sheet
in the wards advising parents of this.
In all cases, if a parent is not coming to theatre with their child for whatever
reason, then they must remain in the ward and should not accompany their
child to the theatre door. This is unsatisfactory and unsafe, since there is
often no one available to look after parents who often wait outside the
theatre door.
In all situations, the final decision regarding parental presence
rests with the anaesthetist.
Intraoperative Management
Useful Drugs See also Aide Memoire on anaesthetic machine
Induction agents
Thiopentone 4-7 mg/kg iv
Propofol 2-4 mg/kg iv
Ketamine 2 mg/kg iv (5-10 mg/kg im)
Muscle relaxants
Suxamethonium 1-1.5 mg/kg (2 mg/kg in neonates)
Atracurium 0.5 mg/kg
Vecuronium 0.1 mg/kg
Mivacurium 0.1-0.2 mg/kg
Analgesics
Morphine 100-200 micrograms/kg(<1year 50-100 micrograms/kg)
Alfentanil 2-5 micrograms/kg
Fentanyl 2-5 micrograms/kg
Remifentanil 0.2-0.3 micrograms/kg/min infusion
Diclofenac 1-2 mg/kg (oral/PR) (3 mg/kg /day)
oral solution allows 1 mg/kg dose to be given to any weight post op
Ketorolac 0-0.3 mg/kg post-op, avoid if bleeding risk
Anti-emetics
Ondansetron 0.1 mg/kg
Dexamethasone 0.1-0.25 mg/kg
Antibiotics
Ceftriaxone 30 mg/kg/day
Benzylpenicillin 10-20 mg/kg/day iv 6 hrly
Ampicillin 30 mg/kg iv 6 hrly
Gentamicin neonate 3 mg/kg 12 hrly
child 2 mg/kg 8 hourly
Cefotaxime 50 mg/kg 8-12 hrly
Cefuroxime 10-30 mg/kg 6 hrly
Augmentin 30 mg/kg 8hrly
Erythromycin 5-12.5 mg/kg 6 hrly
Metronidazole 7.5 mg/kg 6 hrly
Flucloxacillin under 2yrs 62.5 mg 6 hrly
over 2yrs 125 mg 6hrly
Reversal agents
Neostigmine 50 micrograms/kg
Glycopyrrolate 10 micrograms/kg
Management of severe laryngospasm
Laryngospasm is the product of a light plane of anaesthesia associated with a
stimulus, which combines to trigger the protective reflexes of the larynx in
an exaggerated form. Laryngospasm is obviously best avoided if possible, and
the old axiom ‘extubate deep or awake, but never in between’ still stands.
The aim of management is to ensure adequate oxygenation of the patient.
Give 100% oxygen via a tight fitting facemask with the valve firmly screwed
down, or use a T-Piece with the bag providing PEEP. Gentle positive pressure
ventilation may assist ventilation. If the child is becoming increasingly
hypoxic (ie SpO2 <75%) with no signs of resolution, do not hesitate to give
suxamethonium. The use of suxamethonium does not necessarily imply the
need for intubation. Severe laryngospasm is rare during gaseous induction. If
this does occur suxamethonium can be given, by the intra-muscular route (3
mg/kg).
Local and regional anaesthesia
Regional anaesthesia and nerve blocks are widely used in children, usually in
conjunction with general anaesthesia. They provide part of the anaesthetic
and significantly improve patient comfort in the postoperative period.
Up to a maximum dose of 2 mg/kg of 0.25% plain bupivacaine is suitable
for the following techniques: caudal, axillary, ilio-inguinal, penile block and
simple infiltration.
Caudal epidural blockade
Epidural analgesia using a single injection of local anaesthetic to the epidural
space via the caudal approach combines the advantages of a single technique
with a high success rate. The technique has a wide range of indications in
paediatric practice including orchidopexy, circumcision, and inguinal
herniotomy as well as lower limb and pelvic orthopaedic surgery. The median
duration of caudal epidural analgesia is up to 6 hours with 0.25% bupivacaine.
This can be prolonged to 9-16 hours when clonidine 1-2 micrograms/kg is
added to the local anaesthetic solution. A volume of 0.5 ml/kg is enough to
block sacral roots,
1 ml/kg for lower lumbar roots, and 1.25 ml/kg for upper lumbar roots,
achieved by diluting with 0.9% Saline solution to provide the extra volume.
Postoperative care
Post-operative analgesia
1. Paracetamol
Orally
Paracetamol 20 mg/kg loading dose, then 20 mg/kg 4-8hrly to a maximum of
90 mg/kg/day (60 mg/kg/day in neonates)
Rectally
Paracetamol 30-40 mg/kg single loading dose (20 mg/kg in neonates), then
20 mg/kg 6-8hrly to a maximum of 90 mg/kg/day (60 mg/kg/day in neonates)
A higher dose is required rectally, as bioavailability is approximately 50%
compared to that of oral administration.
2. Non-steroidal anti-inflammatory drugs
Useful when combined with opioid techniques where they have an opioid
sparing effect and with local blocks when they prolong the duration of
analgesia
Diclofenac Na: 1-3 mg/kg daily in divided doses orally or PR
Ibuprofen: 5-10 mg/kg 8 hourly orally
Continuous opioid techniques in children
The use of a continuous infusion of opioid provides a consistent and constant
level of analgesia. Dose regimens depend on the age of the child. All children
with an infusion of opioid must have continuous pulse oximetry and high
dependency nursing care.
I.v morphine infusion regimen
Morphine 1mg/kg in 0.9% saline 50mls (=20 micrograms/kg/ml)
maximum 50mg in 50mls
Age
0-1 month: up to 4 micrograms/kg/hour = 0.2ml/hr
>1-3 months: up to 10 micrograms/kg/hour = 0.5ml/hour
>3 months: up to 20 micrograms/kg/hour = 1ml/hour
may need up to 40 micrograms/kg/hour = 2mls/hour
Naloxone should be readily available when morphine is in use (10 micrograms/kg)
Patient-controlled analgesia
Shown to be safe and effective in children over 5 years of age.
Recommended starting setting for patient-controlled analgesia in children
Recommended drug concentration is morphine 1 mg/kg in 0.9% saline 50mls
(=20 micrograms/kg/ml); maximum 50mg in 50mls
Bolus dose 20 micrograms/kg = 1ml; maximum bolus dose = 1mg)
Lockout time 5-10 minutes
Background infusion 4 –20 micrograms/kg/hour = 0.2-1 ml/hour
(especially useful in the first 12-24 hours post-op).
In children less than 5 years and those with relative contra-indications to
PCA, nurse-controlled analgesia may be appropriate. Most regimens for nurse
controlled analgesia use a higher level of background infusion (up to 20
micrograms/kg/hour) with a longer lockout time of approximately 30 minutes.
Management of opioid-induced respiratory depression
support the airway and give high flow oxygen
assist breathing if hypoventilation severe
discontinue opioid administration
give iv naloxone 10 micrograms/kg
repeat naloxone 10 micrograms/kg up to 10 kg
consider naloxone infusion to maintain opioid antagonism at
1-10 micrograms/kg/hour
Further reading
Paediatric Anaesthesia. Sumner and Hatch (Eds), Arnold 1999.
A Handbook of Neonatal Anaesthesia. Hughes, Mather, Wolf. Saunders 1996
Paediatric Intensive Care. Morton (ed) Oxford University Press 1997
Paediatric Anaesthesia – Blackwell Science (Journal)
In ARI and/or RACH anaesthetic departments.