Intraoperative Medications Associated With Hemodynamically Significant Anaphylaxis

Despite variations in definitions used, significant numbers of surgical cases are known to be complicated by anaphylaxis. This may be due to drugs such as antibiotics and neuromuscularblocking drugs or even due to latex and disinfectants. Poorly defined patient risk factors and difficulty in accurate and early identification of anaphylaxis by anesthesiologists increase the intraoperative risks. Epinephrine is a widely accepted first line of treatment, and intravenous fluids, antihistamines, and glucocorticoids offer the second line of treatment for anaphylaxis. Intraoperative anaphylaxis mortality is estimated at 0% to 1.4%. The main objective of the study was to identify drugs and patient factors related to hemodynamically significant anaphylaxis in adult patients undergoing surgery. Possible instances of hemodynamically significant anaphylaxis were studied from the University of Michigan Anesthesia Information Management System database from 2004 to 2015. The primary outcome was hemodynamically significant anaphylaxis: grade III (shock and/or life-threatening smooth muscle spasm) and grade IV (cardiac and/or respiratory arrest). The screening process used physiologic and treatment-based screening algorithm for identifying hypotension followed by treatment suggestive of anaphylaxis in “hemodynamically significant” adult (≥18 years old) patients. Two clinicians manually reviewed all the cases using predefined criteria, and a third clinician adjudicated any disagreements. Confirmed cases of hemodynamically significant anaphylaxis were matched 3:1 with control cases and were further reviewed to create a list of medications administered postanesthesia but before the onset of suspected anaphylactic reaction. Intraoperative medications administered in hemodynamically significant anaphylaxis cases and patient risk factors were compared with control cases. A total of 461,986 were studied; of these, 635 met the initial screening criteria, and of these, 55 cases (1 in 8400) were identified for likely hemodynamically significant anaphylaxis. It was noted that 52 patients experienced hemodynamically significant anaphylaxis (1 patient with 3 instances and 1 patient with 2 instances). Protamine was the only drug associated with an increased risk of hemodynamically significant anaphylaxis (odds ratio, 11.78; 95% confidence interval, 1.40–99.26; P = 0.0233) and that no other category of drugs was associated with an increased risk. Only personal history of anaphylaxis was associated with an increased risk (odds ratio, 77.1; 95% confidence interval, 10.46–567.69; P ≤ 0.0001). Other noted results were as follows: low postoperative follow-up and evaluation of patients; serum tryptase level was sent in only 49% of cases (41% positive vs