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The objective of our study was to determine the maximal non-reactive concentrations for midazolam and ketamine in healthy volunteers using both prick and intradermal skin tests. Twenty-one healthy Caucasian volunteers were tested for midazolam and ketamine using more clustered concentrations (identical for both prick and intradermal tests) than those resulting from decimal dilutions. The criteria for positivity were based on dilutions of drugs that cause wheal and flare reactions in subjects without history of allergy. For the prick method, the concentrations that did not produce wheal and flare were 1 mg/ml for midazolam and 10 mg/ml for ketamine. For intradermal tests, using serial dilutions, we found that the highest concentration for which the subjects did not pass the positivity criteria was 0.25 mg/ml for both drugs. [ABSTRACT FROM AUTHOR]

Anaphylactic shock is a rare, but potentially lethal complication, combining life-threatening circulatory failure and massive fluid shifts. Treatment guidelines rely on adrenaline and volume expansion by intravenous fluids, but there is no solid evidence for the choice of one specific type of fluid over another. Our purpose was to compare the time to achieve target mean arterial pressure upon resuscitation using adrenaline alone versus adrenaline with different resuscitation fluids in an animal model and to compare the tissue oxygen pressures (PtiO2) with the various strategies. Twenty-five ovalbumin-sensitised Brown Norway rats were allocated to five groups after anaphylactic shock induction: vehicle (CON), adrenaline alone (AD), or adrenaline with isotonic saline (AD+IS), hydroxyethyl starch (AD+HES) or hypertonic saline (AD+HS). Time to reach a target mean arterial pressure value of 75 mmHg, cardiac output, skeletal muscle PtiO2, lactate/pyruvate ratio and cumulative doses of adrenaline were recorded. Non-treated rats died within 15 minutes. The target mean arterial pressure value was reached faster with AD+HES (median: 10 minutes, range: 7.5 to 12.5 minutes) and AD+IS (median: 17.5 minutes, range: 5 to 25 minutes) versus adrenaline alone (median: 25 minutes, range: 20-30 minutes). There were also reduced adrenaline requirements in these groups. The skeletal muscle PtiO2 was restored only in the AD+HES group. Although direct extrapolation to humans should be made with caution, our results support the combined use of adrenaline and volume expansion for resuscitation from anaphylactic shock. When used with adrenaline the most effective fluid was hydroxyethyl starch, whereas hypertonic saline was the least effective. [ABSTRACT FROM AUTHOR]