PAEDIATRIC
ANAESTHESIA
GUIDE
DEPARTMENT OF ANAESTHETICS
ROYAL ABERDEEN CHILDREN'S HOSPITAL
A GUIDE TO PAEDIATRIC ANAESTHESIA
Page Number
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
Paediatric Anaesthetist / Bleep No.Office extension / Home No. / Mobile / Pager No.
G. Byers / 2474 50379
A. Campbell / 2798 50441
G. Johnston
(Head of Service) / 2776 50440
M. Bloch
A. Sheikh / 2399 51758
G. Wilson
(Lead clinician HDU) /
- 51759
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) / LengthORAL (cm) / Length
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.
Nebulisedadrenaline 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 / MeanBP 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 requirementsDay 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 pre-operative 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%dextroseDobutamine
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 inductionEvery 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 DrugsSee 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.