Paediatric Anaesthesia Formulas
Fluid requirements
Fasting Guidelines for Pediatric Patients
TYPE Fasting Time (hr)
Clear liquids* 2
Breast milk 4
TYPE Fasting Time (hr)
Infant formula 6†
Solid (fatty or fried) foods 8
*Includes only fluids without pulp; clear tea or coffee without milk products. †The American Society of Anesthesiologists guideline allows a “light breakfast” (tea and plain toast) 6 hours before anesthesia; however, determining what a “light breakfast” means for a child is difficult.
Maintenance Requirements in Children
Weight (kg) Maintenance Requirements in Children
(mL/hour)
0-10 4 (mL/kg)
11-20 40 + 2 (mL/kg)
> 20 kg 60 + 1 (mL/kg)
Replacement of Losses
Procedure Insesnsible losses
Non-invasive (inguinal hernia, clubfoot) 0-2 cc/kg/hr
Mildly invasive (uteteral reimplantation) 2-4 cc/kg/hr
Moderately invasive (bowel reanastamosis) 4-8 cc/kg/hr
Significantly invasive (NEC) > 10 cc/kg/hr
Intraoperative Glucose
Infants: 4 mg/kg/min = 240 mg/kg/hr maintenance requirements D5 = 50 mg/mL Delivery of D5 @
> 4 mL/kg/hr may lead to hyperglycemia
Catheter sizes and their flow rates
MEAN FLOW RATE RANGE (mL/min)
Catheter Size
(gauge)
Length
(inches)
Crystalloid
(gravity)
Crystalloid
(pressure)
Blood
(pressure)
24 0.75 14 to 15 42 to 47 20 to 30
22 1 24 to 26 65 to 77 44 to 50
20 1.25 to 2 38 to 42 103 to 126 69 to 81
18 1.25 to 2 55 to 62 164 to 214 150 to 164
16 2 75 to 81 248 to 280 216 to 286
MEAN FLOW RATE RANGE (mL/min)
Catheter Size
(gauge)
Length
(inches)
Crystalloid
(gravity)
Crystalloid
(pressure)
Blood
(pressure)
14 2 92 to 93 301 to 319 334 to 410
20 8 5 16 3
18 8 13 51 22
16 8 31 97 35
Data summarized from Hodge D III, Fleisher G: Pediatric catheter flow rates. Am J Emerg Med
3:403, 1985.
Paediatric Airway Equipments
Pediatric Endotracheal Tube Size
Age Internal
Diameter (mm)
Depth (cm)
Preterm 2.5 6 - 8
Term 3.0 9 - 10
6 months 3-3.5 10
1 - 2 years 4.0 10 - 11
3 - 4 years 4.5 12 - 13
5 - 6 years 5.0 14 - 15
10 years 6.0 16 - 17
Pediatric Endotracheal Tube Depth
For preemies and neonates (cm) = weight (in kg) + 6 For 1 year or older (cm) = age + 10 cm
Pediatric Airway Equipment
Age Miller Blade
< 32 weeks 00
Term 0 (< 3 kg)
3-18 mo. 1 (3-10 kg)
> 18 mo 2 (> 12 kg)
Pediatric LMA Size
LMA sizes ~ weight (kg) / 20 + 1 (round to nearest 0.5)
Laryngeal mask airway size characteristics
Laryngeal Mask Airway Size Approximate Weight (kg) Cuff Volume (mL)
1 <5 2 to 5
1.5 5 to 10 3 to 8
2 10 to 20 5 to 10
2.5 20 to 30 10 to 15
3 30 to 50 15 to 20
4 50 to 70 ≤30
5 70 to 100 ≤40
6 >100 ≤50
Pediatric-sized laryngeal mask airways and compatible endotracheal tubes[*]
Laryngeal
Mask Airway
Size
Maximum Lubricated
Uncuffed Standard
Endotracheal Tube Inner
Diameter (mm)
Maximum Lubricated Cuffed
Standard Endotracheal Tube
Inner Diameter (mm)
Maximum Flexible
Bronchoscope
Size[†]
1 3.5 3.0 2.7
1.5 4.0 4.0 3.0
2 5.0 4.5 3.5
2.5 6.0[‡]
5.0 4.0
3 — 6.0 5.0
4 — 6.0 5.0
5 — 7.0[†]
5.0
6 — 7.0[†]
5.0
Litman RS: The difficult pediatric airway. In Litman RS, editor: Pediatric anesthesia: The
requisites, St. Louis, 2004, Mosby. *Based o e peri e ts perfor ed the author, As per LMA North A eri a, Largest availa le u uffed endotracheal tube available at The Children's Hospital of Philadelphia.
Laryngoscope blade types and sizes
BLADE TYPE AND SIZE
Age Miller Wis-Hippel Macintosh
Premature neonate 0 — —
Term neonate 0 to 1 — —
1 to 12 mo 1 1 —
1 to 2 yr 1 1.5 2
2 to 6 yr 2 — 2
6 to 12 yr 2 — 3
Endotracheal tube size[*]
Age Weight
(kg)
ID (mm) Length (OT)
(cm)
Length (NT)
(cm)
Suction Catheter
(F)
Premie 0.7 to 1.0 2.5 7 to 8 9 5
Premie 1.0 to 2.5 3.0 8 to 9 9 to 10 5
Newborn 2.5 to 3.5 3.5 9 to 10 11 to 12 6
3 mo 3.5 to 5.0 3.5 10 to 11 12 6
3 to 9 mo 5.0 to 8.0 3.5 to 4.0 11 to 12 13 to 14 6
9 to 18 mo 8.0 to 11.0 4.0 to 4.5 12 to 13 14 to 15 8
1.5 to 3 yr 11.0 to
15.0
4.5 to 5.0 12 to 14 16 to 17 8
4 to 5 yr 15.0 to
18.0
5.0 to 5.5 14 to 16 18 to 19 10
6 to 7 yr 19.0 to
23.0
5.5 to 6.0 16 to 18 19 to 20 10
8 to 10 yr 24.0 to
30.0
6.0 to 6.5 20 to 22 21 to 23 10
10 to 11
yr
30.0 to
35.0
6.0 to
6.5[†]
20 to 22 22 to 24 12
12 to 13
yr
35.0 to
40.0
6.5 to
7.0[*]
20 to 22 23 to 25 12
14 to 16
yr
45.0 to
55.0
7.0 to
7.5[*]
20 to 22 24 to 25 12
Data modified from Smith RM: Anesthesia for infants and children. CV Mosby, 1980, St. Louis;
Davenport HT: Paediatric anaesthesia. Year Book Medical Publishers, 1973, Chicago.
ID, inner diameter; OT, orotracheal tube; NT, nasotracheal tube; F, French size (number is
approximately equal to ID × 4).
* The endotracheal tube should fit so as to allow full normal expansion of both lungs with positive airway
pressure ut to per it a gas leak a out the tu e at 20 to 25 H2O. Cuffed tu e.
Recommended nasotracheal tube dimensions
TUBE LENGTH (L) (cm)
Age (yr) Tube Size (S) (ID, mm) Yates et al. (1987) Rees (1966) Steward (1979)
0 to 3 mo 2.5 to 3.0 9.5 to 11.0 11.8 13.5
4 to 7 mo 3.5 to 4.0 12.5 to 14.0 13.6
1 4.0 14.0 14.5 15.0
2 4.5 15.5 15.2 16.0
3 4.5 to 5.0 15.5 to 17.0 15.6
4 5.0 17.0 16.5 17.0
5 5.0 to 5.5 17.0 to 18.5 16.8
6 5.5 18.5 17.1 19.0
7 5.5 to 6.0 18.5 to 20.0 17.8
8 6.0 20.0 18.3 21.0
9 6.0 to 6.5 20.0 to 21.5 18.8
10 6.5 21.0 19.1 22.0
11 6.5 to 7.0 21.5 to 23.0 19.1
12 7.0 23.0 22.0
Medications for Children
Preoperative Medication in Children
PO Nasal IV IM
Midazolam 0.5 - 1.0 mg/kg 0.05 - 0.10 mg/kg
Fentanyl 1 - 3 ucg/kg
Morphine 0.05 - 0.10 mg/kg
Sufentanil 0.25 - 0.5 ucg/kg
Ketamine 2-4 mg/kg 4-6 mg/kg
Resuscitation Medication in Children
Epinephrine = 10-100 ucg/kg for arrest (100 ucg/kg in ETT), 1-4 ucg/kg for hypotension
Atropine = 0.01 - 0.02 mg/kg (0.3 mg/kg in ETT) - actual dose 0.1 - 1 mg
Adenosine = 0.1 mg/kg (max dose 6 mg)
Lidocaine = 1-1.5 mg/kg
SCh = 2-3 mg/kg
Rocuronium 1 mg/kg
Calcium chloride = 10-20 mg/kg (dilute to 10 mg/cc or else veins will sclerose, try to give
centrally if possible)
Bicarbonate = 1 mEq/kg (dilute to 1 mEq/cc or else veins will sclerose)
Naloxone = 0.1 mg/kg
DEFIBRILLATION = 2 J/kg (can increase up to 4 J/kg)
Preoperative Medication in Children
Midazolam 0.05-0.1 mg/kg IV (0.5-1 mg/kg PO, 15 mg max)
Methohexital 1-2 mg/kg IV (25-30 mg/kg PR, 500 mg max)
Ketamine 1-2 mg/kg IV, 10 mg/kg IM, 5-8 mg/kg PO
Sodium Pentothal 1-2 mg/kg IV (separation), 4-6 mg/kg IV (induction)
Propofol 0.1-1 mg/kg IV (separation), 2-4 mg/kg IV (induction)
Etomidate 0.2-0.3 mg/kg IV
Antibiotic Doses in Children
Cefazolin 25 mg/kg q6-8h up to 1-2 grams
Cefotaxime 20-30 mg/kg q6h
Ampicillin 50-100 mg/kg q6h up to 3 grams
Gentamicin 2-2.5 mg/kg q8h (must monitor serum levels, longer interval in renal
impairment)
Clindamycin 5-10 mg/kg q6-8h up to 900mg
Mezlocillinn 50-100 mg/kg q6h up to 2g
Vancomycin 10 mg/kg q6h up to 1g
Other Useful Medication in Children
Glycopyrrolate 0.01 mg/kg IV, IM, ETT (max 0.4 mg)
Morphine 0.05 - 0.1 mg/kg IV (max 0.4 mg/kg)
Fentanyl 1-5 ucg/kg IV
Ketorolac 0.5 mg/kg IV
Tylenol 20 mg/kg PO, 40 mg/kg PR
Zofran 0.05-0.15 mg/kg
Droperidol 20-25 ucg/kg
Dexamethasone 0.1-0.5 mg/kg for pain, N/V prophylaxis
Neostigmine 0.07 mg/kg
Dexamethasone 0.5-1 mg/kg for tracheal edema
Solumedrol 1 mg/kg IV
Characteristics of volatile anesthetics
MAC (%)
Infant (1 to 6 mo) Child (3 to 10 yr) Adult
Halothane 1.1 0.9 0.7
Enflurane –– –– 1.6
Isoflurane 1.7 1.6 1.2
Desflurane 9.4 8.0 6.0
Sevoflurane 3.3 2.5 2.0
Adapted in part from Jones RM: Desflurane and sevoflurane; inhalation anesthetics for this
decade? Br J Anaesth 65:527, 1990. Copyright © The Board of Management and Trustees of the
British Journal of Anaesthesia. Reproduced by permission of Oxford University Press/British
Journal of Anaesthesia.
Intravenous dosage of opioids in children
Drug As Major Anesthetic As Adjunct As Postoperative
Analgesic
Morphine 2 to 3 mg/kg 0.05 to 0.1 mg/kg per hr 0.05 to 0.1 mg/kg
Fentanyl 50 to 100 mcg/kg 1 to 3 mcg/kg per hr 1 to 2 mcg/kg
Sufentanil 10 to 15 mcg/kg 0.1 to 0.3 mcg/kg per hr —
Alfentanil 150 to 200 mcg/kg 1 to 3 mcg/kg per min —
Remifentanil 0.2 to 1.0 mcg/kg per
min
0.1 to 0.4 mcg/kg per
min
—
Hydromorphone 5 to 10 mcg/kg 3 to 5 mcg/kg per hr 3 to 5 mcg/kg
Intravenous doses of muscle relaxants in children
MAINTENANCE ED95 (mg/kg)
Drug Intubation
(mg/kg)
Bolus
(mg/kg)
Continuous Infusion
(mcg/kg/m)
Infants Children
Mivacurium 0.2 to 0.3 0.1 10 to 20 0.1 0.1
Cisatracurium 0.15 0.1 1 to 5 0.05 0.05
Vecuronium 0.05 to 0.1 0.025 1 0.024 0.026
Rocuronium 0.8 to 1.0 0.3 to 0.5 15 0.2 0.3
Pancuronium 0.1 0.5 — 0.05 0.05
Pipecuronium 0.1 — — 0.035 0.05
Nonsteroidal anti-inflammatory drugs (NSAIDs)
Drug Age Group Dose (mg/kg) Interval
Acetaminophen Preterm Term Load: 20; 15(PO), 20 (PR) q12h
>3 mo Load: 20 to 30; 20 (PO) q8h
Load: 20 (PO); 15 (PO) q4h
40 (PR), 20 (PR) q6h
Diclofenac >1 yr 1 (PO) q8h
Ibuprofen >6 mo 10 to 15 (PO) q6h
Ketorolac >6 mo 0.25 to 0.5 (IM, IV) q6h
Naproxen >6 mo 5 to 10 (PO) q8–12h
Celecoxib >1 yr 1.5 to 3 (PO) q12h
Regional Anaesthesia
I. DOSES OF EPIDURAL ANALGESICS
Usual Doses and Infusion Regimens for Epidural Anesthesia in Pediatric Patients
Agent Initial Dose Continuous Infusion (Max.
Doses) Repeat Injections
Bupivacaine,
levobupivacaine
Solution: 0.25% with
5 µg/mL (1/200,000)
<4 mo: 0.2 mg/kg/hr
(0.15 mL/kg/hr of a 0.125%
0.1 to 0.3 mL/kg
every 6-12 hr of a
Agent Initial Dose Continuous Infusion (Max.
Doses) Repeat Injections
epinephrine
Dose:
<20 kg: 0.75 mL/kg
20-40 kg: 8-10 mL (or
0.1 mL/year/number of
metameres)
>40 kg: same as for adults
solution or 0.3 mL/kg/hr of
a 0.0625% solution)
4-18 mo: 0.25 mg/kg/hr
(0.2 mL/kg/hr of a 0.125%
solution or 0.4 mL/kg/hr of
a 0.0625% solution)
>18 mo: 0.3-0.375 mg/kg/hr
(0.3 mL/kg/hr of a 0.125%
solution or 0.6 mL/kg/hr of
a 0.0625% solution
0.25% or 0.125%
solution (according to
pain scores)
Ropivacaine
Solution: 0.2%
Dose: same regimen in
mL/kg as for bupivacaine
(see above)
Same age-related infusion
rates in mg/kg/hr as for
bupivacaine (usual
concentration of
ropivacaine: 0.1%, 0.15%,
or 0.2%)
Do not infuse for more than
36 hr in infants < 3 mo
0.1 to 0.3 mL/kg
every 6-12 hr of a
0.15% or 0.2%
solution (according to
pain scores)
Adjuvants
Avoid in infants < 6 mo
Fentanyl (1-2 µg/kg) or
sufentanil (0.1-0.6 µg/kg)
or clonidine (1-2 µg/kg)
Select only one additive:
Fentanyl: 1-2 µg/mL
Sufentanil: 0.25-0.5 µg/mL
Morphine: 10 µg/mL
Hydromorphone: 1-3 µg/mL
Clonidine 0.3 at 1 µg/mL of
solution
Morphine (without
preservatives): 25-
30 µg/kg every 8 hr
Recommendations for dosing caudal and epidural blocks.
Concentration Dose Possible Additives
Single-dose caudal 0.175% to
0.5%
0.75 to 1.25 mL/kg not
to exceed 3 mng/kg
Epinephrine 2.5 to 5
mcg/mL
Clonidine 1 to 2 mcg/kg
Morphine 30 to 70
mcg/kg
Continuous caudal or lumbar
epidural catheters
0.1% to 0.25% 0.4 mL/kg per hr or 0.2
to 0.4 mg/kg per hr
Fentanyl 2 to 5 mcg/mL
Hydromorphone 5 to 10
mcg/mL
Continuous thoracic epidural 0.1% to 0.25% 0.3 mL/kg per hr or 0.1
to 0.2 mg/kg per hr
Fentanyl 2 to 5 mcg/mL
Hydromorphone 5 to 10
mcg/mL
Bupivacaine, levobupivacaine, or ropivacaine may be used. Greater concentrations and larger doses
should be reserved for levobupivacaine or ropivacaine. Doses and concentrations should be reduced
in infants. Children less than 2 years of age who receive morphine centrally require 24-hour
monitoring after its delivery.
II. SPINAL ANAESTHESIA DOSES
Volumes of local anesthetic solutions for peripheral nerve blocks and regional anesthesia in
children
Block Volume (mL/kg)
Axillary 0.2 to 0.5
Interscalene 0.33
Sciatic 0.15 to 0.2
Femoral 0.5
Intravenous 0.5 to 10
Caudal 0.5 to 1.0
Intrapleural (infusion) 0.5 (per hr)
Usual Doses of Local Anesthetics for Spinal Anesthesia in Neonates and Former Preterm
Neonates Younger than 60 Weeks of Preconceptual Age (up to a Weight of 5 kg)
Local Anesthetic Dose (mg/kg) Volume (mL/kg) Duration (min)
Tetracaine 1% 0.4-1.0 0.04-0.1 60-75
Tetracaine 1% with epinephrine 0.4-1.0 0.04-0.1 90-120
Bupivacaine 0.5% isobaric or hyperbaric 0.5-1.0 0.1-0.2 65-75
Levobupivacaine 0.5% 1.0 0.2 75-88
Ropivacaine 0.5% 1.08 0.22 51-68
Usual Doses of Local Anesthetics for Spinal Anesthesia in Children and Adolescents
Local Anesthetic Usual Dose(s)
0.5% Isobaric or hyperbaric bupivacaine 5 to 15 kg: 0.4 mg/kg (0.08 mL/kg)
>15 kg: 0.3 mg/kg (0.06 mL/kg)
0.5% Isobaric or hyperbaric tetracaine 5 to 15 kg: 0.4 mg/kg (0.08 mL/kg)
>15 kg: 0.3 mg/kg (0.06 mL/kg)
0.5% Isobaric levobupivacaine 5 to 15 kg: 0.4 mg/kg (0.08 mL/kg)
Local Anesthetic Usual Dose(s)
15-40 kg: 0.3 mg/kg (0.06 mL/kg)
>40 kg: 0.25 mg/kg (0.05 mL/kg)
0.5% Isobaric ropivacaine 0.5 mg/kg (max 20 mg)
III. RECOMMENDATIONS FOR DOSING OF PERIPHERAL NERVE BLOCKS
Recommended Volumes of Local Anesthetic for Single-Shot Upper Limb Blocks with
Neurostimulation by Patient Weight
Patient Weight
Conduction Block ≤10 kg 11-30 kg 31-60 kg >60 kg
Brachial plexus above
clavicle 1 mL/kg
10 mL + 0.5 mL/kg
above 10 kg
20 mL + 0.25 mL/kg
above 30 kg 30 mL
Brachial plexus below
clavicle 0.5 mL/kg
5 mL + 0.25 mL/kg
above 10 kg
10 mL + 0.15 mL/kg
above 30 kg 15 mL
Any nerve trunk at
elbow 0.2 mL/kg 0.15 mL/kg 0.15 mL 10 mL
Any nerve trunk at
wrist 0.05 mL/kg 0.05 mL/kg 0.05 mL/kg
3-
5 mL
Recommended Volumes of Local Anesthetic for Single-Shot Lower Limb Blocks with
Neurostimulation
Conduction Block ≤10 kg 11-30 kg 31-60 kg >60 kg
Lumbar plexus (psoas
compartment) 1 mL/kg
10 mL + 0.5 mL/kg
above 10 kg 20 mL 20 mL
Femoral 0.5 mL/kg 5 mL + 0.35 mL/kg
above 10 kg
12 mL + 0.3 mL/kg
above 30 kg 25 mL
Fascia iliaca 1 mL/kg 10 mL + 0.5 mL/kg
above 10 kg
20 mL + 0.25 mL/kg
above 30 kg 30 mL
Proximal sciatic 1 mL/kg 10 mL + 0.5 mL/kg
above 10 kg
20 mL + 0.3 mL/kg
above 30 kg 30 mL
Sciatic in popliteal fossa 0.3 mL/kg 3 mL + 0.2 mL/kg
above 10 kg 6 mL + 0.15 mL/kg 12.5 mL
Usual Local Anesthetic Infusion Rates with or without Bolus Doses of Either Ropivacaine
0.2%, Bupivacaine 0.125%, or Levobupivacaine 0.15% to 0.2% for Continuous Peripheral
Nerve Blocks
Techniques Plexus and Proximal Conduction Nerve
Blocks *
Axillary and Popliteal
Blocks
Infusion rate 0.2 mL/kg/hr up to 10 mL/hr 0.1 mL/kg/hr up to
5 mL/hr
Bolus doses 0.2 mL/kg up to 5 mL 0.1 mL/kg/hr up to
3 mL/hr
Maximum bolus doses per
hour 3 3
Regional Technique Bolus Dose
(mLμ/kg)[*]
Continuous Infusion (mLμ/kg per hr)
Axillary Parascalene 0.2 to 0.5 0.2 to 0.4 0.1 to 0.2 0.1 to 0.2
Femoral or lateral femoral
cutaneous
0.3 to 1 0.15 to 0.3
Fascia iliaca 0.5 to 1 0.15 to 0.3
Lumbar plexus 0.5 to 1 0.15 to 0.3
Sciatic 0.3 to 1 0.15 to 0.3
Ilioinguinal/iliohypogastric 0.25 NA
Penile block 0.1 NA
Paravertebral 0.5 0.2 to 0.25
NA, not applicable.
Bupivacaine, levobupivacaine, or ropivacaine may be used. For bolus dosing, lower concentrations
such as 0.2% to 0.25% should be used in infants and young children, whereas concentrations of
0.375% to 0.5% should be used in children >5 to 8 years of age. For continuous infusions, lower
concentrations such as 0.1% to 0.2% of all agents are acceptable
Ref:
1. SMITH'S Anesthesia for Infants and Children, Seventh Edition.
2. Miller's Anesthesia - 8th ed.