Intradermal testing in the diagnosis of acute anaphylaxis during anaesthesia--results of five years experience.

Intradermal testing has been used in the diagnosis of acute anaphylactic reactions during anaesthesia in 51 patients. Positive results occurred in 32 patients and confirmation was possible in 26. Only in one case did a combination of history and intradermal testing not give a diagnosis. Nine of the negative results were confirmed. Intradermal testing is of no value in the diagnosis of reactions to local anaesthetics or colloids but has great value in determining the cause of reactions due to induction agents or muscle relaxants if performed under controlled conditions. It is safe, and requires no expertise in performance or interpretation.     

Intradermal compared with prick testing in the diagnosis of anaesthetic allergy

We have tested the hypothesis that intradermal testing is a more effective method for determining the drug responsible for anaesthetic anaphylactic reactions than prick testing in 212 consecutive patients, aged more than 10 yr, referred to an anaesthetic allergy clinic over a 4-yr period. The study was a prospective, non-randomized design. Intradermal testing was conducted using a previously described method and diluted drugs, and prick testing using undiluted drugs (with the exception of opioid analgesics which were diluted 1:10). The tests were performed on individual patients' forearms on the same occasion. Patients were followed-up to determine the results of subsequent anaesthesia and the difference between tests was analysed using kappa and tau statistics. There was 93% agreement overall between the paired tests. Which test detected the drug responsible was dependent on diagnostic criteria for positivity. The differences between the tests were not statistically significant. Using both tests improved predictability by 67% (tau = 0.67, P < 0.001). We conclude that in the absence of data to support one test being superior, other factors influence the choice of test. Prick testing was cheaper, and the reduction in pain and trauma with prick testing makes it more suitable for children. However, there are no data available on the safety of subsequent anaesthesia based on the results of prick testing alone, and reliability with time has not been assessed. Intradermal testing may be easier for the infrequent user. Skin testing is valuable in the investigation of anaesthetic anaphylaxis whichever test is chosen. When there is doubt both tests should be performed.      

The nature and reported incidence of suspected perioperative allergic reactions: A cross-sectional survey

Study objectivePerioperative allergic reactions (POHs) are common and can lead to severe intraoperative instability and even mortality. In contrast to the situation in developed countries, where databases of perioperative anaphylaxis are well documented and analyzed, relevant data are lacking in China. Therefore, we aimed to conduct a national survey to explore the characteristics of perioperative allergic reactions, as well as the knowledge and attitudes toward management and reporting among anesthesiologists.DesignCross-sectional survey.SettingAnesthesia department.PatientsA nationally representative sample comprising anesthesiologists from 12 province-level regions was selected.MeasurementsA 20-item questionnaire was designed and validated using the Delphi method. Survey distribution was performed between June 2019 and January 2020 by the Chinese Society of Anesthesiology (CSA), which is the official academic society of Chinese anesthesiologists. Responses were compiled and analyzed.Main resultsWe received responses from 4389 anesthesiologists across China. The estimated rate of suspected POH was 2/1000 patients (0.2%). On average, an anesthesiologist encountered 2.1 suspected POH cases per year. Neuromuscular blocking agents (NMBAs) were perceived as the most common causative agents, followed by antibiotics and succinylated gelatin. The rates of referral and allergy consultations were very low. Institutional support, including protocol development, cognitive aids, and tool kits, was not ideal. Additionally, the management of POH varied substantially. Most anesthesiologists believed that reporting and documenting POH was necessary.ConclusionsOur survey revealed that POH is commonly encountered by Chinese anesthesiologists, but few patients are referred to allergy specialists or clinics for further investigation. A standardized recommendation based on research and data derived from Chinese patients is required.     

Slowing of the heart during anaphylactic shock

Five patients are reported with anaphylactic shock reactions due to i.v. administration of atracurium, methicillin, amidotrezoate (n = 2) and plasma. In these patients a fall in heart rate (HR) from 5-50 beats.min-1 was recorded during the hypotensive period. In three of the patients HR was 40 beats.min-1 or less, and in two of the patients a hypotensive bradycardiac episode spontaneously reappeared after normal HR and BP were established. Central venous pressure (CVP) fell in one patient from 0.8 to 0.6 kPa as HR and BP decreased while arterial oxygen tension remained normal. All patients were in a stable condition after treatment with volume expansion and sympathomimetic drugs. These observations indicate that anaphylactic shock is associated with a strong and sometimes persistent vagal tone to the heart in parallel with the early reaction to hypotensive hypovolaemic shock.     

Marked changes in the core temperature during anaphylactic shock

Three cases of anaphylactic shock were reported in which the core temperature was measured continuously. Two core temperature thermister probes were fixed on the forehead and the sole. Temperature dissociation between the core and the periphery disappeared in a few minutes after the administration of the causative agents. The clinical signs of the anaphylactic shock such as erythema, wheal and marked hypotension also developed in a few minutes after the disappearance of temperature dissociation. Thus treatment of anaphylactic shock could be started even before the patients develop severe hypotension. This clinical study suggests that a sudden disappearance of the temperature dissociation is a incipient sign of anaphylactic shock and to monitor the core as well as the peripheral temperature is a useful method for early diagnosis and treatment of anaphylactic shock.     

Skin testing in the investigation of reactions to intravenous anaesthetic drugs. A prospective trial of atracurium and tubocurarine

Intradermal skin testing is widely used to determine the causative drugs of presumed anaphylactic anaesthetic reactions. This paper sets out to evaluate the usefulness of skin tests, both intradermal and prick testing, in the prediction of anaesthetic reactions. The muscle relaxant drugs tubocurarine and atracurium were chosen for study since they are known to produce a high incidence of minor histaminoid reactions. A trial was conducted in 22 female patients about to undergo elective gynaecological surgery for non-malignant conditions. In intradermal tests, positive wheal and flare reactions to one or other relaxant (diluted 1 in 1,000) occurred in 17 patients and reactions to both drugs in 11 patients. Despite this high incidence of positive reactions, none of the patients had received either drug previously, a view confirmed by the negative results of prick testing. Likewise, when anaesthetized for surgery using atracurium or tubocurarine allocated randomly, the minor histaminoid manifestations observed showed no correlation whatsoever with the intradermal tests results. The results of the trial, combined with external reports to this centre, indicate that intradermal testing of anaesthetic drugs, particularly muscle relaxants, produces a high incidence of false positive results. This probably reflects their pharmacological activity rather than antigenicity. It is recommended, therefore, that skin testing should be reserved for situations in which there are strong indications from laboratory tests, backed by case history, of immune sensitization.     

Anaphylaxis during anesthesia - role of skin prick testing in diagnosing multiple sensitivities

The true incidence of anaphylactic reactions and their associated morbidity and mortality remain poorly defined. This is due to uncertainties in reporting accuracy and exhaustivity. A 23 years old male developed severe anaphylaxis under general anesthesia with cardiovascular collapse, bronchospasm and angio-edema. He was promptly managed with intravenous Adrenaline, Hydrocortisone, colloid solutions and Promethazine. The temporal relation suggested Atracurium to be the cause. However, skin prick test, performed 8 weeks later, showed a very strong (+++) positive test for Atracurium and mild sensitivity (+) with Suxamethonium. No sensitivity to Nalbuphine, Thiopentone or Pancuronium was noted. The relevant information was endorsed in patient's medical record sheet for his future exposure.     

Intradermal injection of GFP-producing adipose stromal cells promotes survival of random-pattern skin flaps in rats

Background

Tissue necrosis is a common complication in operations that use skin flaps for reconstructive surgery. Here we demonstrate the beneficial effect of autologous genetically modified adipose-derived stromal cells (ASCs) in the survival of random-pattern skin flaps.

Methods

ASCs were isolated from the inguinal fat pad of Wistar rats and genetically modified in order to permanently produce green fluorescent protein (GFP) using the Sleeping Beauty transposon technology. Autologous GFP-producing cells were then injected intradermally into random-pattern skin flaps planned on the dorsal area of rats.

Results

Injection of ASCs resulted in significant improvement of skin flap survival. Histological analysis showed that the connective tissue was almost intact in skin flaps treated with ASCs in contrast to disorganized tissues from mock-treated skin flaps. GFP ASCs were detected in the endothelium of blood vessels co-expressing the endothelial marker von Willebrand factor, thus suggesting that they promote blood vessel regeneration.

Conclusions

These findings indicate that transplantation of autologous GFP ASCs improve survival of skin flaps. This methodology suggests that the use of genetically modified ASCs producing, e.g., angiogenic factors may facilitate survival and integration of flaps in plastic surgery.     

Personal protective equipment related skin reactions in healthcare professionals during COVID‐19

Since the outbreak of COVID‐19 pandemic, clinicians have had to use personal protective equipment (PPE) for prolonged periods. This has been associated with detrimental effects, especially in relation to the skin health. The present study describes a comprehensive survey of healthcare workers (HCWs) to describe their experiences using PPE in managing COVID‐19 patients, with a particular focus on adverse skin reactions. A 24‐hour prevalence study and multi‐centre prospective survey were designed to capture the impact of PPE on skin health of hospital staff. Questionnaires incorporated demographics of participants, PPE type, usage time, and removal frequency. Participants reported the nature and location of any corresponding adverse skin reactions. The prevalence study included all staff in intensive care from a single centre, while the prospective study used a convenience sample of staff from three acute care providers in the United Kingdom. A total of 108 staff were recruited into the prevalence study, while 307 HCWs from a variety of professional backgrounds and demographics participated in the prospective study. Various skin adverse reactions were reported for the prevalence study, with the bridge of the nose (69%) and ears (30%) being the most affected. Of the six adverse skin reactions recorded for the prospective study, the most common were redness blanching (33%), itchiness (22%), and pressure damage (12%). These occurred predominantly at the bridge of the nose and the ears. There were significant associations (P < .05) between the adverse skin reactions with both the average daily time of PPE usage and the frequency of PPE relief. The comprehensive study revealed that the use of PPE leads to an array of skin reactions at various facial locations of HCWs. Improvements in guidelines are required for PPE usage to protect skin health. In addition, modifications to PPE designs are required to accommodate a range of face shapes and appropriate materials to improve device safety.