Perioperative Anaphylaxis in an Egyptian Population.
Perioperative Anaphylaxis in an Egyptian Population.
Perioperative anaphylaxis is associated with significant morbidity and mortality. Most
 textbooks describe it as a rare event of the order of 1 in 10 to 1 in 20,000 general
 anaesthetic cases. However, a recent study in the United Kingdom suggested that 1 in 350
 cases have features suspicious of perioperative anaphylaxis. This study suggests that
 perioperative anaphylaxis may be under recognised and under reported.

 When perioperative anaphylaxis is recognised, it would be ideal to carry out investigations
 firstly to confirm the diagnosis of anaphylaxis and secondly to identify the causative agent.
 The latter can be difficult in the context of anaesthesia where the patient is exposed to
 several drugs and other reagents in a short space of time.

 One of the interesting aspects of perioperative anaphylaxis is that there is variability in
 its epidemiology between different countries, for example between the United Kingdom, France,
 Scandinavia and Australia and New Zealand. There are currently no data from Egypt to include
 in such comparisons and to inform clinical practice.

 As well as being at risk if a drug allergen is not identified, patients can also be at risk
 from an incorrect allergy label. The most common example of this is penicillin allergy where
 fewer than 10% of patients with a history of penicillin allergy are found to be allergic.
 Incorrect penicillin allergy labels are potentially harmful for patients attending for
 surgery because the label independently increases the risk of developing infection to
 resistant organisms, longer hospital stays and mortality.
Perioperative anaphylaxis is associated with significant morbidity and mortality. Most
 textbooks describe it as a rare event of the order of 1 in 10 to 1 in 20,000 general
 anaesthetic cases. However, a recent study in the United Kingdom suggested that 1 in 350
 cases have features suspicious of perioperative anaphylaxis. This study suggests that
 perioperative anaphylaxis may be under recognised and under reported.

 When perioperative anaphylaxis is recognised, it would be ideal to carry out investigations
 firstly to confirm the diagnosis of anaphylaxis and secondly to identify the causative agent.
 The latter can be difficult in the context of anaesthesia where the patient is exposed to
 several drugs and other reagents in a short space of time.

 One of the interesting aspects of perioperative anaphylaxis is that there is variability in
 its epidemiology between different countries, for example between the United Kingdom, France,
 Scandinavia and Australia and New Zealand. There are currently no data from Egypt to include
 in such comparisons and to inform clinical practice.

 As well as being at risk if a drug allergen is not identified, patients can also be at risk
 from an incorrect allergy label. The most common example of this is penicillin allergy where
 fewer than 10% of patients with a history of penicillin allergy are found to be allergic.
 Incorrect penicillin allergy labels are potentially harmful for patients attending for
 surgery because the label independently increases the risk of developing infection to
 resistant organisms, longer hospital stays and mortality.

 Aim of the work:

 This project proposes the following studies:

 1. The incidence of suspected perioperative anaphylaxis in an Egyptian population.

 2. Defining normal mast cell tryptase concentrations in perioperative patients in Egypt.

 3. Defining non-irritant concentrations of neuromuscular blocking drugs.

 4. Acute penicillin allergy de-labelling.

 Patient and Methods:

 1. In order to define the incidence of possible anaphylaxis, data will be collected on 1000
 consecutive general anaesthetic procedures in Assiut University Hospitals. After each
 elective operating list the anaesthetist will be asked to complete a form in which they
 will document the number of patients receiving general anaesthesia on the list and the
 number of those patients who developed any of the following features: unexpected,
 unexplained hypotension; unexpected bronchospasm resistant to treatment; angioedema;
 urticaria; severe itching; widespread erythema.

 2. Tryptase is a relatively stable protein released from mast cells alongside histamine
 during allergic anaphylaxis. Mast cell tryptase is recognised as a useful biomarker for
 perioperative anaphylaxis but there is debate concerning what degree of change in mast
 cell tryptase produces the greatest combination of sensitivity and specificity for
 perioperative anaphylaxis. Variable results from different countries suggest that
 population specific normal responses may need to be defined.

 This study will be conducted in Assiut University Hospitals. A blood cell sample for
 mast cell tryptase will be taken immediately prior to surgery and 1 hour following
 induction of anaesthesia in the following groups of patients (n = 30 in each case):

 1. Children undergoing elective surgery between the ages of 3 and 10 years

 2. Adults between the ages of 16 and 30 years undergoing orthopaedic trauma surgery

 3. Adults more than 60 years of age undergoing orthopaedic surgery

 4. Women of any age undergoing gynaecological surgery

 5. Adults of any age undergoing emergency general surgery

 6. Adults undergoing cardiac surgery involving cardiopulmonary bypass (samples will be
 taken immediately preoperatively, prior to cardiopulmonary bypass and 1 hour after
 cardiopulmonary bypass)

 7. Women undergoing caesarean section under general or regional anaesthesia

 3. Skin prick testing and intradermal testing with potential drug allergens are a useful
 part of investigation of perioperative anaphylaxis. Epidemiological data suggest
 differences between populations in the incidence of anaphylaxis with NMBDs and also
 differences between the different NMBDs implicated. There is controversy about the
 appropriate concentration of drugs used in skin testing and different regimens may
 explain some of the variability.

 Skin prick and intradermal testing will be done using available neuromuscular blocking
 drugs. For each drug serial dilutions will be used for the tests to determine the
 highest concentration that does not produce a positive response.

 The study will be done on 2 groups of individuals with no history of anaesthetic
 problems. The first group will be patients, who as far as can be determined, have not
 received any NMDBs during their lifetime and the second group will be patients who it is
 known have received an NMDB without complication.

 4. Patients presenting at Assiut University Hospital for elective surgery with a
 self-reported penicillin allergy will be questioned. Patients suitable for this study
 will be those who are deemed to be low risk for true penicillin allergy. The criteria
 for identifying a patient at low risk are as follows:

 1. History of allergic reaction occurring more than 15 years ago

 2. Symptoms are either unknown, a non-specific rash (erythema and non-raised rash that
 was not itchy), nausea or diarrhoea

 3. No symptoms suggestive of a true allergic reaction (swelling, urticaria rash, itch,
 anaphylaxis) Low risk patients will be entered in an abbreviated acute penicillin
 allergy challenge test. This will be done in a monitored environment such as an
 anaesthetic room or post anaesthesia care unit where they can be monitored
 continually and with availability of an anaesthetist.

 An intravenous cannula will be inserted and non-invasive monitoring established. For the
 challenge the prophylactic penicillin that is to be used for the surgery will be given at the
 standard dose divided at 20 minute intervals. At time zero 10% of the total dose will be
 given. Providing that no symptoms of allergy develop within 20 minutes a further 40% of the
 total dose will be given and after a further 20 minutes, assuming no symptoms of allergy, the
 remaining 50% of the total dose will be administered. The patient will be monitored for at
 least another 20 minutes before administration of anaesthesia.
Inclusion Criteria:

 -  In order to define the incidence of possible anaphylaxis, data will be collected on
 1000 consecutive general anaesthetic procedures in Assiut University Hospitals.

 -  A blood cell sample for mast cell tryptase will be taken immediately prior to surgery
 and 1 hour following induction of anaesthesia in the following groups of patients (n =
 30 in each case):

 1. Children undergoing elective surgery between the ages of 3 and 10 years

 2. Adults between the ages of 16 and 30 years undergoing orthopaedic trauma surgery

 3. Adults more than 60 years of age undergoing orthopaedic surgery

 4. Women of any age undergoing gynaecological surgery

 5. Adults of any age undergoing emergency general surgery

 (g) Women undergoing caesarean section under general or regional anaesthesia

 -  Skin prick and intradermal testing will be done using available neuromuscular blocking
 drugs. The study will be done on 2 groups of individuals with no history of
 anaesthetic problems. The first group will be patients, who as far as can be
 determined, have not received any NMDBs during their lifetime and the second group
 will be patients who it is known have received an NMDB without complication.

 -  Patients presenting at Assiut University Hospital for elective surgery with a
 self-reported penicillin allergy will be questioned. Patients suitable for this study
 will be those who are deemed to be low risk for true penicillin allergy. The criteria
 for identifying a patient at low risk are as follows:

 1. History of allergic reaction occurring more than 15 years ago

 2. Symptoms are either unknown, a non-specific rash (erythema and a non-raised rash
 that was not itchy), nausea or diarrhoea.

 3. No symptoms suggestive of a true allergic reaction (swelling, urticaria, rash,
 itching, anaphylaxis)