sign in sign up
<<
Home , Soy allergy

Sedation for an MRI for a Child with an Egg and Soy and a Recent Meal

Pioneer in Pediatric Anesthesiology: Burton S. Epstein, M.D. Senior Faculty: Carolyn F. Bannister, M.D. Junior Faculty: Kenneth S. Stewart, D.O.

OBJECTIVES After attending this session, the attendant should be able to: • Discuss options for sedation for an MRI. • Discuss anesthetic implications of Magnetic Resonance Imaging. • Cite ASA NPO guidelines including the updated ASA practice guidelines (3/11). • Discuss the anesthetic implications for multiple food including . • Create a plan for an offsite anesthetic emergency

STEM CASE – KEY QUESTIONS

A 4-year old male with a history of meningioma is coming for an MRI of the head. The tumor was resected 6 months ago and the patient has returned to his normal state of health. The MRI was ordered for surveillance and to check for postoperative changes. His last meal was toast, cheese, and apple juice 6 hours ago. The sedation service (non-anesthesia personnel) at your hospital does not feel comfortable with his NPO status and requests Anesthesiology’s help with this patient. He is an otherwise healthy boy with multiple food allergies including eggs and soy.

1. Is there anything else you would like to know prior to induction of anesthesia?

2. What monitors are appropriate for this case?

3. What do you think about his NPO status? What is your hospital’s policy in regards to NPO status? Are there any pharmacologic agents you would consider in regards to the patient’s NPO status (ex. ranitidine, etc.)?

4. How do you normally take care of patients for an MRI? Would you premedicate this patient? If yes, what would you use? Will you sedate or choose a GA? If sedation, what drugs will you use?

5. If GA, how would you induce anesthesia for this patient? What are your anesthetic concerns?

You decide on a mask induction and will place an IV after the patient is asleep. The mask induction goes uneventfully. The vital signs at this time are HR=90s, Non-invasive BP=100/62, and O2 sat=100%. The anesthetist helping you places a tourniquet on the patient and proceeds in looking for an IV site. The anesthetist has difficulty finding and placing an IV. As she continues to look, it becomes harder to mask ventilate the patient. You are only able to move small tidal volumes and the patient is apneic. She finally places the IV and you decide to intubate.

6. What drugs will you use to intubate?

On direct laryngoscopy, the patient had a Grade I view and intubation was accomplished quickly. You connect the patient to the anesthesia circuit without difficulty. Pulmonary compliance is poor and there is limited chest rise. End-tidal CO2=20 and wave capnogram is dampened. Upon auscultation there are very faint breath sounds bilaterally.

7. What is your differential diagnosis?

The non-invasive blood pressure is now 52/30 and the heart rate is in the 140s from 90s. You recycle the cuff and the blood pressure is still 52/30. O2 sats are falling and are now in the 80s.

8. Does this change your differential?

9. What do you want to do? Do you need additional monitors?

10. Is there anything that you need to do differently because you are in the MRI suite? Where is emergency equipment in the MRI suite (code cart, MH cart, etc.)?

The patient has been stabilized and you are ready to proceed with the MRI.

11. Are there any labs or studies that could be done to help with a definitive diagnosis on the cause of the previous event?

The MRI finishes without any further events and the radiologist reads the scan as “normal”.

12. What would be your criteria to send this patient home? Does this differ from another patient coming for an outpatient MRI?

13. What information will be discussed with the family regarding the anesthetic?

Anaphylaxis and Anesthesia was defined by the second National Institute of Allergy and Infectious Disease/ and Anaphylaxis Network symposium as “…a serious allergic reaction that is rapid in onset and may cause death.” At one time non-IgE mediated reactions were termed “anaphylactoid”, but the European Academy of Allergology and Clinical recommended that this term no longer be used and that there is both Ig-E mediated and non-IgE mediated anaphylaxis. The latter term has not been uniformly accepted. Anaphylaxis during the perioperative period can be a challenging event. Since it is a clinical syndrome involving various systems, diagnosis can be delayed or missed. It is estimated that the incidence of anaphylaxis under anesthesia is 1:3,180 – 20,000. The highest incidence is with neuromuscular blocking agents (NMBAs) and occurs in 1 in 6,500 administrations (60% of anaphylaxis cases). After NMBAs, latex (12-16% of reactions) and antibiotics (8%) are the largest culprits. Cardiac arrest and fatalities secondary to anaphylaxis occur in 0.7- 10% of reactions. Believed underreporting accounts for the large ranges in incidence. Less frequently involved agents include: dyes, hypnotic agents, local anesthetics, opioids, colloids, aprotinin, protamine, chlorhexidine, and IV contrast agents. In children, the incidence of anaphylaxis is 1:7,700 where latex accounts for 76% of the reactions. The clinical features of anaphylaxis under anesthesia may include the cardiovascular system (tachycardia, bradycardia, arrhythmias, , cardiovascular collapse, and/or cardiac arrest), pulmonary system (bronchospasm), erythema, urticaria, and . A grading scale was described by Ring and Messmer (see TABLE 1). Grades I and II are not usually life-threatening. Grades III and IV are emergencies.

Grades Clinical Signs I Cutaneous-mucous signs: erythema, urticaria with or without angioedema II Moderate multivisceral signs: cutaneous-mucous signs +/- hypotension +/- tachycardia +/- Dyspnea +/- GI disturbances III Life-threatening mono- or multivisceral signs: cardiovascular collapse, tachycardia, or bradycardia +/- cardiac dysrhythmia +/- bronchospasm +/- cutaneous-mucous signs +/- gastrointestinal disturbances IV Cardiac arrest Table One: Ring and Messmer Grading Scale for Anaphylaxis by Clinical Manifestations

The patient’s sensitivity and route of administration may determine the severity of the reactions. Intravenous administration or mucous membrane exposure is likely to have the most severe reactions and faster onset whereas, rectal administration may take 15-30 minutes for onset of symptoms. Risk factors for anaphylaxis include: patients who have had a previous immediate life-threatening event that was not investigated; patients with risk factors for latex allergies (see below); patients with a history mastocytosis; and patients who are allergic to one of the drugs/products that will likely be used during an anesthetic. Treatment of anaphylaxis starts with removal of the offending agent. After that the following measures should be taken: (1) Call for help; (2) discontinue the anesthetic drugs when anaphylaxis occurs during induction; (3) maintain the airway with 100% oxygen, (4) in the case of a Grade III or IV reaction, give early; (5) expand intravascular volume; (6) consider placing the patient in Trendelenburg position; and (7) speak with the surgeon about abbreviating or terminating the procedure. Of note, epinephrine is never indicated for Grade I reactions and only occasionally needed for Grade II reactions. A recent Danish study (Anesthesiology July 2011) concluded if you suspect anaphylaxis due to hemodynamic changes, you should administer epinephrine early. Although not statistically significantly different, the group given epinephrine early had a shorter post-event treatment course. Occasionally, epinephrine does not restore hemodynamics. This clinical syndrome has been named “anaphylactic shock refractory to catecholamines”. In these rare events, norepinephrine or glucagon should be used in patients on ß-blocker therapy and vasopressin used in others. Recently (2008), methylene blue was used to treat catecolamine and vasopressin-resistant anaphylaxis. Its interference with nitric oxide-mediated relaxation is believed to be the mechanism for working in this situation. If bronchospasm occurs, it should be treated with inhaled ß2 agonists. If bronchospasm occurs in the face of cardiovascular collapse, than IV epinephrine remains the first-line therapy. IV corticosteroids should be given early for their anti-inflammatory properties although effects may take up to 4-6 hours. H-1 and H-2 blockers are frequently given during anaphylaxis episodes although they have never been studied in placebo-controlled trials. Pretreatment (to prevent anaphylaxis) with corticosteroids and receptor blockers remains controversial. Only IV contrast has shown consistently to be helped by pretreatment. The overall incidence is not decreased, but if anaphylaxis occurs in this setting, severity is reduced with pretreatment. Any allergic or anaphylactic reaction under anesthesia must be investigated. This should consist of three parts: (1) perioperative and postoperative testing to confirm the nature of the reaction, (2) identification of the offending agent (or possible cross-reactivity), and (3) providing recommendations for future anesthetics. Serum tryptase is the only blood test that should be drawn during the event (within 15 and 60 minutes in grade I and II reactions; within 30 minutes and 2 hours in Grade III and IV reactions) and at 24 hours after the event. This is elevated with and will be elevated in both anaphylaxis and anaphylactoid. In non-IgE reactions (anaphylactoid), the elevation will not be as pronounced. Absence of tryptase does not preclude a Grade I or II reaction and its elevation may be seen in underlying mastocytosis. testing may be recommended, but these tests should be ordered by an allergist or immunologist. There are in vitro specific IgE assays, but these are less sensitive than skin testing.

Latex Allergy as a medical entity started to be examined more carefully in the 1980s when a large number of case reports of latex anaphylaxis under general anesthesia were reported. Local reactions were also being reported in healthcare workers wearing latex gloves. The prevalence of latex in the general adult population is 1-6.7% and in the pediatric population 0.3- 4%. The frequency of anaphylactic reactions in children has decreased since the 1990s. It is hypothesized that there are three reasons for this: (1) elimination of latex-containing products from clinical settings; (2) awareness of at-risk children; and (3) improved laboratory identification of latex allergic patients. The prevalence of latex sensitization among anesthesiologists and nurse anesthetists is 12.-15.8%. The prevalence is lower in pediatric anesthesiologists probably because many pediatric hospitals have reduced their latex use. Not all latex reactions are clinically significant. Latex sensitization is defined as “the presence of immunoglobulin antibodies to natural rubber latex products without clinical manifestations.” This does not always lead to an allergic reaction and it is not currently known why some individuals will develop latex sensitivity while others do not. There are more than 200 polypeptides that have been identified as potential latex . Thirteen of them (Hevea brasiliensis [Hev b]), Hev b 1-13, are the ones that the International Union of Immunological Societies has recognized as primary allergens. Children at risk for developing sensitivity include those with spina bifida; those with congenital anomalies including urologic, gastrointestinal, and tracheoesophageal defects; those that have had more than five surgeries or procedures; those with cerebral palsy and/or mental retardation; those that are quadriplegic; and those with a history of . Children with spina bifida have a greater prevalence of problems with latex because of earlier ages of first surgeries, they have to be catheterized daily (with latex catheters), atopy, and genetics. Latex-specific IgE antibodies have been found in 1-16% of atopic children who had never had surgery. Allergies to certain fruits (and vegetables) also puts a child at risk for a latex reaction. This cross-sensitivity includes allergies to avocado, banana, kiwi, papaya, peach, nectarine, chestnut, tomato, bell pepper, carrot, and ficus trees. This “latex fruit syndrome” carries an 11% risk of a reaction to latex if the child has an allergy to one of the above. Management of latex allergies has been recommended by the ASA and includes a thorough H & P, application for a medical alert bracelet, a latex-free cart, a list of latex-free devices, and signage on the patient’s medical record and room (or operating room). Children with a latex allergy should be the first case of the day or 2 ½ hours after the last operating room latex exposure (because of aerosolized latex particles from latex-containing gloves). All members of the OR team must be alerted to the child’s allergy (potential or documented) and the operating suite should be prepared accordingly. One question that continually arises is whether one should remove the tops of medication vials that contain latex for patients at risk. Two mechanisms for contamination may occur: (1) the needle puncture through the rubber stopper may cause small latex particles from the anterior of the stopper to come in contact with the medication and (2) surface proteins on the stopper may come in contact with the medication. Although conflicting, there is evidence that adverse reactions can occur when drawing up medications with these stoppers in place. Some have advocated removing the stoppers, “pop the tops”, prior to drawing up medications, but this is not without problems as many of these tops were not made to be removed and sterility is violated. Current evidence seems to support “single sticks” in pristine medication stoppers. The majority of hospital pharmacies have been doing this for latex-allergic patients with good success. The most recent guidelines for management of latex allergies by the American College of Allergy, , and Immunology (1996) recommends for healthcare facilities to avoid using latex-containing products. De Queiroz et al. states that in her institution since going to a completely latex-free environment despite over 25,000 interventions/5 years there have been no cases of latex anaphylaxis. Her institution decided to adopt a latex-free environment after a 2-year old died from latex anaphylactic shock during a minor emergency procedure. Any suspected latex reaction should be confirmed by specific laboratory testing: either skin prick testing or specific IgE to latex protein (RAST test). Skin prick testing is very sensitive and specific whereas the RAST is less sensitive [IgE are positive in 60- 90% of sensitized patients].

Can I use if my patient has an egg or soy allergy? Propofol, chemical name 2, 6-di-isopropyl-phenol, is formulated in an emulsion with intralipid. The formulation is very slightly soluble in water, contains 1% propofol, and is white color. Within the formulation is 10% soy bean oil, glycerol 2.25%, 1.2% egg , and disodium edentate (0.005%). Sodium hydroxide is used to adjust the pH to 7-8.5. The U.S. insert for Diprivan (propofol) by AstraZenceca, says that the “…emulsion in contraindicated in patients with a known hypersensitivity to DIPRIVAN Injectable Emulsion or its components…” In Australia the insert warns of use in egg- or soy-allergic patients and in the United Kingdom it warns of soy/peanut- (but not egg-) allergic individuals. Despite not mentioning food allergies, many American practitioners worry about propofol use in egg- or soy- allergic patients. All three formulations (U.S., Australia, U.K.) are supplied by AstraZeneca and contain soy oil and egg lecithin [in U.S. and Australia; egg yolk phosphatide containing egg lecithin in U.K.]. Propofol hypersensitivity reactions are rare compared to some of the other drugs used in anesthesia like muscle relaxants and antibiotics. A case series of 14 patients with propofol hypersensitivity reactions did not mention whether any of the patients had egg or soy allergies. The five published cases of allergic reactions to propofol in patients with an egg-allergy had no allergy testing performed i.e. no skin prick testing or intradermal tests. The Association of Anesthetists of Great Britain and Ireland guideline (2009) for suspected anaphylaxis under anesthesia claim that there is no evidence propofol should be avoided in patients with egg or soy allergies. A retrospective chart review looking at propofol administration to egg- and/or soy-allergic pediatric patients in Australia’s Children’s Hospital at Westmead in Sydney (1999-2010) was published in Anesthesia and Analgesia in July 2011. The investigators identified 1162 egg-allergic patients of whom 42 patients (71 episodes) had an anesthetic with propofol. 14 patients were eventually excluded [none of these had a reaction to propofol]. Twenty-eight patients (43 episodes) remained for analysis. Nineteen children had a history of a clinical reaction to egg which was deemed mild or moderate in severity prior to getting propofol. 2 of these patients had an anaphylactic reaction from egg. The remaining children (n = 9) had never ingested egg, but had a strongly positive skin prick test (SPT) for egg white (≥ 7 mm) and a positive test for egg yolk (≥ 3 mm) and were asked to avoid eggs. 19 children had a single episode of propofol administration with the others having 2 or more episodes. In this same study no child with a sole soy allergy and an allergic reaction to propofol could be identified. 12 patients with peanut allergies (cross-reactivity with soy was a concern) were identified and none had a reaction when given propofol. There was only 1 allergic reaction after propofol administration in a 7 year old with multiple food allergies and an episode of anaphylaxis at age 4 after sucking a confectionary containing egg albumin. After this episode he avoided all egg containing products including baked egg. He avoided all nuts and sesame after positive allergy testing. He was drinking without problems although he did have positive allergy testing for soy. Skin prick testing was also positive for egg and peanut. This patient was having endoscopy for . 15 minutes after receiving a second dose of propofol he developed generalized erythema and urticaria. There were no pulmonary or hemodynamic changes and IM epinephrine, IV hydrocortisone, and oral trimeprazine resolved symptoms. Subsequently, a SPT to propofol was positive although not performed on intralipid. Latex SPT was negative 5 months earlier. The authors of this study warn of propofol use in patients with a history of egg anaphylaxis. Propofol consists of egg lecithin (lipid) derived from heated egg yolk. It has been reported to contain trace amounts of yolk, but no egg white proteins. Only 2 of 9 egg yolk proteins are allergenic and it is impossible to know what the contaminant consists of. There is only one case of a child with an egg allergy reacting to egg lecithin after an oral challenge. 75% of egg-allergic children can tolerate egg yolk without a reaction. Martin-Hernandez et al. quantified the amount of egg protein contaminant in egg lecithin. All proteins were from egg yolk and were present at 50 ppm (0.005%). This amount if applied to propofol (calculated = 5 mcg) would not be enough to cause a reaction on oral challenge (200 mcg lowest observed threshold for egg protein reaction in an egg-allergic patient), but no way to know if this amount could cause a reaction given IV. Recent studies on the H1N1 vaccine have shown it to be safe in egg-allergic children. In a prospective study of 830 non-anaphylactic egg-allergic children only 2% had an allergic reaction to the H1N1 vaccine. This was not statistically different than the non-egg-allergic control. Murphy et al. suggest the following when testing a patient with an egg-allergy who may have had a hypersensitivity reaction to propofol:

Interpretation of Allergy Testing in Egg-Allergic Patients with Hypersensitivity reactions to Propofol Propofol solution skin prick and/or intradermal 10% Intralipid solution skin prick and/or Interpretation and recommendation result intradermal result Positive Negative Allergy likely to isopropyl or phenol groups on propofol Negative Positive Allergy may be due to contaminant egg yolk protein. Discuss with an allergist option of an oral challenge with egg lecithin or egg yolk in hospital Positive Positive Allergy may be due to isopropyl or phenol groups receiving propofol and/or egg contaminant protein. Suggest alternate for future anesthesia Negative Negative Consider reaction to other administered drugs, other potential source (ex. latex), or anaphylactoid (non-IgE) reaction to propofol

References: • Belso N et al: Propofol and fentanyl induced perioperative anaphylaxis. Br J Anaesth 2011; 106: 283-4 • Bradley AD, Tober KS, Brown RE: Use of propofol in patients with food allergies. Anaesthesia 2008; 63: 439 • De Queiroz M et al: Latex allergy in children: modalities and prevention. Pediatric Anesthesia 2009; 19:313-9 • DeWachter P, Mouton-Faivre C, Emala CW: Anaphylaxis and anesthesia. Anesthesiology 2009; 111:1141-50 • Ewan PW et al: BSACI guidelines for the investigation of suspected anaphylaxis during general anesthesia. Clinical and Experimental Allergy 2009; 40:15-31 • Garvey LH et al: Treatment with epinephrine (adrenaline) in suspected anaphylaxis during anesthesia in Denmark. Anesthesiology 2011; 115: 111-6 • Heitz JW, Bader SO: An evidence-based approach to medication preparation for the surgical patient at risk for latex allergy: is it time to stop being stopper poppers? J Clin Anes 2010; 22:477-83 • Jamieson V, Mackenzie J: Allergy to propofol? Anaesthesia 1988; 43:70. • Katz JD, Holzman RS: Natural rubber latex allergy: considerations for anesthesiologists, ASA Committee on Occupation Health of Operating Room Personnel. American Society of Anesthesiologists; 2005. Available at: http://www.asa-hq.net/publicationsAndServices//latexallergy.pdf. Accessed August 2011. • Mertes PM et al: Perioperative anaphylaxis. Immunol Allergy Clin N Am 2009; 429-51 • McHale SP, Konieczko K: Anaphylactoid reaction to propofol. Anaesthesia 1992; 47: 864-5 • Murphy A, Campbell DE, Baines D, Mehr S: Allergic reactions to propofol in Egg-allergic children. Anesth Analg 2011; 113: 140-44 • Nishiyama T, Hanaoka: Propofol-induced bronchoconstriction: two case reports. Anesth Analg 2001; 93: 645-6 • Propofol [package insert]. Wilmington, DE: AstraZeneca; 2005 • Sampathi V, Lerman J: Perioperative latex allergy in children. Anesthesiology 2011; 114:673-80 • Sussman G, Gold M: Guidelines for the management of latex allergies and safe latex use in health care facilities. American College of Allergy, Asthma, and Immunology; 1996. Available at: http://www.latexallergyresources.org/resourcemanual/PDF/GuidelinesforManagement.pdf. Accessed August 2011. • Swanson MC, Bubak ME, Hunt LW, Yunginger JW, Warner MA, Reed CE: Quantification of occupational latex in a medical center. J Allerrgy Clim Immunol 1994; 94:445-51 • Tashkandi J: My patient is allergic to eggs, can I use propofol? A case report and review. Saudi J Anaesth 2010; 4(3): 207-8