TheSaxonPlan

TheSaxonPlan t1_j1epi76 wrote

I've never had to dose two days in a row as our surgeries are 4-5 days apart and we use short-acting (and very stinky) isoflurane gas for quick post-op procedures like fixing their sutures/staples or administering fluids. But even with that length of time, we often have to increase the dose by 10-20% to achieve sufficiently deep anesthesia.

Yeah, the xylazine is for muscle relaxation and a little bit for the pain-killing effect. Since we are literally drilling through the skull and putting a needle into their brain, we don't want any twitches or wiggles! Don't know much about ketamine in people, though I am intrigued by its use as an anti-depressant!

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TheSaxonPlan t1_j1eh1v8 wrote

We use a ketamine/xylazine mix for long-acting anesthesia during mouse brain surgeries in the brain cancer research lab I work in.

>"Ketamine ia a noncompetitive, centrally acting, dissociative general anesthetic that provides amnesia, analgesia, and immobility. Ketamine typically is used as an adjunct anesthetic, due to its limited ability to provide adequate skeletal muscle relaxation. When combined with xylazine, the combination is regarded as the agent of choice for rodent injectable anesthesia. The popularity of ketamine–xylazine (KX) is mainly due to its supplemental effects (that is, analgesic properties, muscle relaxation, and sedation)."

>"Xylazine (Rompun, Bayer) produces moderate sedation and minimal analgesia in rabbits. It is seldom used as a sole agent but is given in combination with ketamine. The combination causes cardiovascular and respiratory depression, and cardiac arrhythmias are produced at high doses. Xylazine and ketamine have been associated with a high mortality rate (Flecknell et al., 1983)."

Ketamine info source

Xylazine info source

I can attest to the lethality of ketamine/xylazine. We try to titer our doses to be the minimum necessary to keep mice asleep and immobile, but not all mice respond the same, and they develop resistance to ketamine the longer it is used. We sometimes have to "bump" their doses and even small amounts can lead to respiratory and/cardiac failure. Our senior tech has successfully resuscitated several mice by doing mini chest compressions and restored breathing. I've saved two this way. But we still lose between 1-5% of mice due to overdose in our experiments.

I am a doctor, but the Ph.D. kind, not the M.D. kind lol

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