5-04
1) RECOMMENDATIONS
a) General Approach
i) Patients under 12 weeks of age are consider at higher risk during anesthetic events
ii) They possess little cardiac reserve
(1) These patients are much more dependent on heart rate for cardiac output
iii) They have an increased oxygen requirement and very small airways making for an increased overall risk of hypoxia
iv) They are more prone to hypothermia
v) They generally require lower doses of sedatives, tranquilizers, and injectable anesthetics
(1) Renal and hepatic functions are not yet mature and will delay drug clearance
vi) They are prone to hypoglycemia
(1) Withholding food for only 4 hours prior to anesthesia helps to minimize this concern
(2) Offering food within 2 or 3 hours of recovery is also recommended
Pre-anesthetic Medications i) Opioids combined with benzodiazepines are effective preanesthetic agents
(1) Dose reductions are in order especially if under 6 to 8 weeks of age
ii) Anticholinergics are recommended to help maintain adequate heart rate and cardiac output
(1) Glycopyrrolate would be preferred over atropine
iii) Acepromazine and alpha-2 agonists like medetomidine and xylazine should be avoided
c) Induction
i) Preoxygenate whenever possible
ii) Standard induction agents can be used if venous access is available
(1) Give carefully to effect
(a) Expect to need a lower total amount per kg
(2) Propofol is a good choice when given carefully to effect
iii) Masking may be necessary when there is no direct venous access
(1) Intubation is highly recommended whenever possible
d) Maintenance
i) Isoflurane or sevoflurane
ii) Nonrebreathing systems are recommended for neonatal patients
(1) Reduced work of breathing
(2) Lighter weight system is advantageous
e) Support
i) Fluid support is important
(1) Neonates are more sensitive to fluid overload
(a) Basic fluid rates from 5 to 10 ml/kg/hr are usually sufficient
(2) If a standard IV catheter is not an option, intraosseous fluids are an effective next choice
(a) Fluids contain 2.5 % or 5.0 % dextrose may be necessary for these patients
ii) Monitor body temperature – provide safe supplemental heat
6) PRECAUTIONS
a) Pre-anesthetic Medications
i) Acepromazine, xylazine, and medetomidine are not recommended
ii) Keep the doses of all agents on the low end of the dose range
Induction i) Give carefully to effect
c) Maintenance
i) A circle system is not recommended
d) Support
i) Do not use microwaved rice bags – their use has been associated with major third degree patient burns