I've been researching poison control centers.
The AAPCC website answered one of my questions: It is standard procedure to follow up on calls. The following report, in fact, gives numbers for those treated at a medical facility and the various treatment outcomes (none, minor, moderate, major, death). (You can do a word search for "nicotine" to find the relevant tables.)
Here is their report for the most recent national statistics, 2011:
https://aapcc.s3.amazonaws.com/pdfs/annual_reports/2011_NPDS_Annual_Report_-_Final.pdf