Thanks for those details. I notice the page you got them from appears to be available to read
here on Google books. Dr Goldstein does not seem to give the actual mg ketamine doses used on that page, but just the concentration of the liquid ketamine solution (concentrations of 1:10 or 1:1).
Although nasal sprays are typically metered around 0.1 ml for each spray, so it should be possible to work out the mg dosage of ketamine in each 0.1 ml spray.
Looking that page, Goldstein appears to be using ketamine there as an agent that acts locally on the trigeminal nerve (a nerve which is found in the eyes, nose and mouth), rather than an agent that has a systemic effect. So he may be using lower doses of ketamine for this local purpose.