Ethylene oxide


Ethylene oxide is a gas capable of killing microorganisms by the alkylation of the sulfur-containing proteins. Since it is a highly inflammable gas, it is used in association with both CO2 (90%) and fluoric hydrocarbons. In such conditions, ethylene oxide sterilizes at a temperature of 40° and a humidity of 40% within 4 hours.
 
It is used to sterilize various medical instruments and supplies that would not tolerate sterilization by heat.
 
Incidence
Severe but non-fatal reactions: 4.2 out of 1000000 dialyzers sold.
 
4/100000 hemodialysis sessions with hollow-fiber dialysers.
 
Risk factors
Atopy.
 
Use of cuprammonium cellulose dialyzers.
 
Frequent exposure (spina-bifida).
 
Clinical manifestations
General: anaphylactic shock
 
Cutaneous: urticaria, angioedema, itching, flushing.
 
Respiratory: bronchospasm.
 
ENT: rhinitis.
 
Other: local intra-articular reactions (reconstructive knee surgery); sterile shunt malfunction.
 
Diagnostic methods
Cutaneous testing with ETO-HSA.
 
Skin prick-tests: 1 mg/ ml then;
Intradermal skin-tests: 0.02 ml ETO-HSA 10 µg/ml; 100µg/ml; 1mg/ ml.
 
Positive predictive value: 80%.
Negative predictive value: 96%.
 
Specific IgE (ELISA, RAST).
 
Correlation between ETO-specific IgE and allergic symptoms during dialysis.
 
Mechanisms
The quantity of ETO remaining in the dialyzer after washing can interact with human albumin and induce the formation of allergens with a cross-linking agent.
 
Management
Sterilization by heat is not possible.
 
Catheters should be washed in a physiologic solution then left in a well-ventilated place in order to remove all trace of the ethylene oxide used (not always feasible).
 
In Japan, the use of steam or gamma radiation made adverse reactions to ethylene oxide disappear.
 
Frequent reuse of compatible membranes (cheaper and safer).
 
Rinsing of the blood compartment and all lines of a cuprammonium cellulose dialyzer with 2 liters of sterile saline.
 
Rinsing of the dialysate compartment with 10 liters of dialysate.

References

  1. Kraske G.K, Shinaberger J.H, Klaustermeyer W.B, "Severe hypersensitivity reaction during hemodialysis", Ann. Allergy. Asthma. Immunol., 1997; 78 (2): 217-20 
  2. Purello D’Ambrosio F, Savica V, Gangemi S, Ricciardi L, Bagnato G.F, Santoro D, Cuzzocrea S, Bellinghieri G, "Ethylene oxide allergy in dialysis patients", Nephrol. Dial. Transplant., 1997; 12 (7): 1461-3 
  3. Pittman T, Kiburz J, Steinhardt G, Krock J, Gabriel K, "Ethylene oxide allergy in children with spina bifida", J. Allergy. Clin. Immunol., 1995; 96:486-8 
  4. Pittman T, Wiliams D, Rathore M, Knutsen A.T, Mueller K.R, "The role of ethylene oxide allergy in sterile shunt malfunctions", Br. J. Neurosurg., 1994; 8 (1): 41-5 
  5. Grammer L.C, Roberts M, Wiggins C.A, Fitzsimons R.R, Ivanovich P.T, Roxe D.M, Patterson R, "A comparison of cutaneous testing and ELISA testing for assessing reactivity to ethylene oxide-human serum albumin in hemodialysis patients with anaphylactic reactions", J. Allergy. Clin. Immunol., 1991; 87: 674-6 
  6. Röckel A, Klinke B, Hertel J, Baur X, Thiel C, Abdelhamid S, Fiegel P, Walb D, "Allergy to dialysis materials", Nephrol. Dial. Transplant., 1989; 4 (7): 646-52

As in all diagnostic testing, the diagnosis is made by the physican based on both test results and the patient history.