Background: Anaphylaxis is a significant health concern within the community.  The early administration of adrenaline to patients experiencing anaphylaxis has long been recognised as the cornerstone of treatment.  Health-care providers, including general practitioners, nurses and paramedics, are well equipped to manage anaphylaxis through the administration of adrenaline.  Patients themselves also often have adrenaline auto injectors, allowing early self-management.  The objective of this study was to determine the rates of adrenaline administration and identify the administering persons for all anaphylaxis patients presenting to ambulance services in Tasmania from January 1st 2008 until December 31st 2011 by using a retrospective chart review.  Methods: Ambulance Tasmania electronic case reports (n=226 421) from the period January 1st 2008 to December 31st 2011 were searched for all cases fitting the parameters of anaphylaxis, allergy or allergic reaction.  Of these cases, 373 were given a final paramedic diagnosis of anaphylaxis and constituted the primary data for this report. Results: Ambulance Tasmania attended 373 patients during the study period that were given a final primary diagnosis of anaphylaxis - of these 59 (15.8%) were excluded, leaving 314 electronic records for analysis.  Of the cases identified, 71.7% (n=225) were administered adrenaline according to paramedic records.  Adrenaline was administered by a range of health professionals, including general practitioners (n=27), paramedics (n=159), ambulance volunteers (n=4), nurses (n=1) and other health professionals (n=3).  Adrenaline was self-administered by 12.4% (n=28) of patients, with an additional 11.6% (n=26) receiving adrenaline from a non-health care worker (layperson).  In 10.2% of cases (n=23) adrenaline was administered by more than one provider.  Administration of adrenaline prior to paramedic arrival was evident in fewer than 10% of cases treated with adrenaline (n=22). Conclusion: The early administration of adrenaline in anaphylaxis is often vital for patient recovery. This study shows that adrenaline is administered by a number of different providers, with early administration accounting for only 9.8% of presentations treated with adrenaline. These findings raise the question, is adrenaline being administered early enough and often enough to improve health outcomes?

Tachyphylaxis has been ascribed to tissue acidification after repeated injections of acidic local anesthetic solutions. We studied the effect of pH on the duration of action of bupivacaine to determine the validity of this proposed mechanism of tachyphylaxis by injecting bupivacaine solutions adjusted to pH 4.2 or 6.8 into a surgically implanted system created to permit in vivo irrigation of rat sciatic nerves with local anesthetic. Tachyphylaxis developed at both pH values. The results fail to support the acidification hypothesis as there was no statistically significant effect of a 400-fold difference in hydrogen ion concentration on the development of tachyphylaxis or the duration of motor dysfunction.