The effect of high dose morphine compared to fentanyl infusion on serum levels of mast cell tryptase during cardiac surgery

Date
2016-12
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : Stellenbosch University
Abstract
Background: Morphine directly activates cutaneous mast cells in a seemingly dose-dependent manner, resulting in the release of both histamine and tryptase into the bloodstream. Tryptase is almost exclusively stored in mast cells. Elevated serum tryptase concentrations serve as an indicator of mast cell activation and have become the most frequently used laboratory investigation in anaphylaxis. Following a clinical diagnostic dilemma our study was aimed at answering whether mast cell tryptase concentration remains useful in supporting the diagnosis of anaphylaxis even after administration of high dose morphine. Methods:We conducted a non-blinded, randomized controlled trial comparing the effects of fentanyl and high dose morphine, on serum mast cell tryptase concentrations. A power analysis was performed. Twenty adults undergoing cardiac surgery were randomly assigned to one of two opioid regimens. Both groups received a fentanyl bolus of 3 to 8 mcg/kg at induction. In the fentanyl group this was followed by a fentanyl infusion of 5 to 10 mcg/kg/hr until completion of surgery. Patients in the morphine group received morphine 1 mg/kg infused over thirty minutes. Baseline serum mast cell tryptase concentrations were determined directly prior to induction of anaesthesia and again 90 minutes after the start of the opioid infusion. The primary endpoint was statistical differences in tryptase concentrations between the morphine and fentanyl groups at the two time periods. Results: Ten patients of similar demographics were enrolled in each group. In the fentanyl group the second, 90-minute mast cell tryptase concentration was statistically significantly (10.1%) lower (p = 0.006) than baseline. Despite the 95% confidence interval of the difference between the means (-1.06 to -0.34 mcg/L) not including zero , this was not a clinically important difference. In the morphine group serum mast cell tryptase concentrations in the second (90 minute) sample were not statistically different from baseline values, the 95% confidence interval including zero. No between-group differences in tryptase concentration were detected. One patient in the morphine group exhibited a clinically significant 50,4% increase in tryptase concentrations, albeit from a high baseline of 11.9 mcg/L, which in this small study constitutes a prevalence of 10% (95% CI 1.8% to 40.4.) Conclusion: In this small pilot study, serum mast cell tryptase concentrations were unaffected by whether fentanyl or high dose morphine was administered. The null hypothesis, that there is no significant increase in serum mast cell concentrations after high dose morphine compared to fentanyl during cardiac anaesthesia and surgery, was therefore accepted. Larger studies are however needed to ensure a robust result, especially in the morphine group
Agtergrond: Morfien aktiveer kutane mastselle direk op 'n oënskynlik dosis-afhanklike wyse, wat lei tot die vrystelling van beide histamien en tryptase in die bloedstroom. Tryptase word feitlik uitsluitlik gestoor in mastselle. Verhoogde serum tryptase konsentrasie dien as 'n aanduiding van mastsel aktivering en het die mees gebruikte laboratorium ondersoek in anafilakse geword. Na 'n kliniese diagnostiese dilemma, is ons studie daarop gemik om die vraag te beantwoord of mastsel tryptase konsentrasie steeds nuttig is in die diagnose van anafilakse selfs na toediening van hoë dosis morfien. Metodes: Ons het 'n nie-geblinde, gerandomiseerde studie gedoen om die effek van fentaniel en hoë dosis morfien op serum massel tryptase konsentrasies te vergelyk. 'n Krag analise is uitgevoer. Twintig volwassenes wat hartchirurgie sou ondergaan is ewekansig toegewys aan een van twee opioïed regimens. Beide groepe het 'n fentaniel bolus van tussen 3 en 8 mkg/kg met induksie ontvang. In die fentaniel groep is dit gevolg deur 'n fentaniel infusie van 5 tot 10 mkg/kg/uur tot die einde van chirurgie. Pasiënte in die morfien groep het morfien 1 mg / kg oor dertig minute ontvang. Serum mastsel tryptase konsentrasies is bepaal direk voor induksie van narkose en weer 90 minute na die aanvang van die opioïed infusie. Die primêre eindpunt was statistiese verskille in tryptase konsentrasie tussen die morfien en fentaniel groepe by die twee tydpunte. Resultate: Tien pasiënte met soortgelyke demografie is ingeskryf in elke groep. In die fentaniel groep was die tweede, 90 minute mastsel tryptase konsentrasie statisties beduidend (10.1%) laer (P = 0,006) as basislyn. Ten spyte daarvan dat die 95% -vertrouensintervalle van die verskil tussen die gemiddelde (-1,06 tot -0,34 mkg/L) nie nul insluit nie, sluit dit nie ‘n klinies belangrike verskil in nie. In die morfien groep het serum mastsel tryptase konsentrasies in die tweede (90 minute) monster nie statisties betekenisvol verskil van die basislyn waardes nie, en sluit die 95% -vertrouensintervalle nul in. Geen tussen-groep verskille in tryptase konsentrasie is opgespoor nie. Een pasiënt in die morfien groep het 'n klinies beduidende toename van 50,4% in tryptase konsentrasies gehad, hoewel vanaf 'n hoë basislyn van 11,9 mkg/L. In hierdie klein studie is dit 'n voorkoms van 10% (95% CI 1.8% tot 40.4.) Gevolgtrekking: In hierdie loodsstudie is serum mastsel tryptase konsentrasies nie beinvloed deur of fentaniel of hoë dosis morfien toediening nie. Die nul-hipotese, dat daar geen beduidende toename in serum mastsel konsentrasie na hoë dosis morfien in vergelyking met fentaniel tydens kardiale narkose en chirurgie is nie, is dus aanvaar. Groter studies word egter benodig om 'n seker gevolgtrekking te kan maak, veral in die morfien groep.
Description
Thesis (MMed)--Stellenbosch University, 2016.
Keywords
Anaphylaxis, Morphine -- Administration, Cardiac surgery, Mast cells, UCTD, Fentanyl
Citation