I echo Jim's sentiment about the "unknown" effect of ketamine on the developing CNS, particularly in the very young infant. Incidentally, the topical anesthetic does NOT have to be an injection of buffered lidocaine. I would also consider using the needle free jet injection device (J-Tip). It is painless, cost effective and works promptly.
Ref: “Cost Effectiveness
Analysis of Topical Anesthetics during Peripheral IV Insertion in Pediatrics.” Arch
Pediatr Adolesc Med 2008; 162(10): 952-961.
From: "Chamberlain, Jim" <[log in to unmask]>
However, we really need to ask ourselves whether the known and unknown risks of procedural sedation are worth it for a procedure that is only painful for about 15 seconds of lidocaine injection. Even this pain can be minimized by use of a topical anesthetic and by buffering the lidocaine.
Nigovic LE et al showed that NON-use of local anesthetic is independently associated with traumatic lumbar punctures (Ann Emerg Med 2007;49:762). This echoes a previous study by Carraccio C et al (Arch Dis Pediatr Adol Med 1996:150;1044.
Animal studies suggest that the young mammalian brain is especially susceptible to neuronal apoptosis from some anesthetic agents. Ketamine does this as well. Benzodiazepines potentiate the effect.
Please review Steve Green's article on ketamine (reference posted here earlier this week).
Adequate local anesthesia should provide you with a non-squirming infant for an LP, without the risks of procedural sedation.
James Chamberlain, MD
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