Diagnosis of perioperative anaphylaxis.

Every agent used during the perioperative period may be involved and have the potential to trigger both allergic, IgE and non-IgE reaction as well as non-specific (non-allergic) reactions. In many cases, an allergic mechanism cannot be ruled out and systematic investigations should be tested of all drugs and agents the patient was exposed to prior to the reaction. The complexity of agents used for anaesthesia and surgery present challenges when attempting to identify the culprit drugs and select proper testing to better recognition of trigger. The diagnosis of preoperative anaphylactic or anaphylactoid reaction is clinical and based upon the presence of characteristic symptom and signs that begin suddenly and developed rapidly in most cases. Elevations of mast cell mediators such as tryptase and histamine in the blood can help to distinguish anaphylaxis from other disorders that present with similar clinical picture. The secondary investigations of adverse perioperative drug reactions are highly specialised and include skin testing, in vitro testing and in some cases challenge tests. Any suspected reaction during anaesthesia must be extensively investigated and these diagnostic tests should be done in specialised centres. The cooperation between anaesthesiologists and allergists is necessary to provide the necessary diagnostic tests to identify the responsible drug, to carry out prevention and to provide recommendations for future anesthetic procedures.

Photoplethysmographic evaluation of sympathectomy during lumbar epidural analgesia: A randomized comparison of 0.125% ropivacaine and 0.125% levobupivacaine.

BACKGROUND: There are no data on the difference between the impact of ropivacaine and levobupivacaine on sympathetic nerve fibers during central neuraxial blocks. We hypothesized that there is no difference in the degree of sympathectomy between the two drugs during lumbar epidural analgesia for labor pain. METHODS: Sixty healthy parturients were randomized to the type of local anesthetic-opiod solution administered in the epidural space: 10 mL of 0.125% ropivacaine + 100 mcg of fentanyl or 10 mL of 0.125% levobupivacaine + 100 mcg of fentanyl. After the baseline measurement, photoplethysmography signal from the first toe of the leg was recorded 5, 10 and 20 minutes after administration of epidural analgesia. RESULTS: Area under the curve and the pulse transit time of the toe photoplethysmography increased in both groups during the first 20 minutes after administration of epidural analgesia (P < 0.001 for both parameters in both groups). No difference in the degree of sympathectomy was found between the groups for the area under the curve. The difference in the change of the pulse transit time suggests that the two local anesthetics might differ in the degree of sympathectomy (P = 0.024). CONCLUSION: 0.125% ropivacaine and 0.125% levobupivacaine do not differ in the terms of sympathectomy-mediated side effects of the epidural block for labor analgesia. However, the photoplethysmography findings suggest a certain difference in the degree of sympathectomy between the two local anesthetics.