Nurse induced respiratory depression by succinylcholine--the 'hero syndrome'.

A nurse administered the neuromuscular blocking agent succinylcholine (SUX) to at least one patient and gave first aid in the therapy of unexpected respiratory depression. SUX is regarded as an undetectable and thus perfect poison due to its short half-life and degradation to the endogenous compounds choline and succinic acid. However, SUX and especially its metabolite succinylmonocholine (SMC) were found in plasma and urine a few hours after administration by means of high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Compared to clinical studies, the window of detection was sufficient to gain definite proof; in other cases no samples were collected. The nurse enjoyed high reputation with the doctors. According to the court she wanted to present herself spectacularly as the first and decisive rescuer to demonstrate her special abilities and capacities, perhaps to receive a better job in the hospital. Considering the actual case, the hero syndrome is not limited to fire-fighters.

A fully validated isotope dilution HPLC-MS/MS method for the simultaneous determination of succinylcholine and succinylmonocholine in serum and urine samples.

A high performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS) method for the simultaneous detection of succinylcholine (SUX) and its metabolite succinylmonocholine (SMC) in serum and urine is presented. For internal standardization using isotope dilution, the deuterated compounds SUX-d(18) and SMC-d(3) were employed. Full validation was performed according to international guidelines. Solid-phase extraction (SPE) of acidified samples was accomplished using Strata-X polymeric reversed phase cartridges together with heptafluorobutyric acid (HFBA) as ion-pairing reagent. Separation was achieved within 13 min on a Phenomenex Synergi Hydro RP C18 column (4 microm, 150 x 2 mm) using a gradient of 5 mM ammonium formate buffer pH 3.5 and acetonitrile.To ensure the method's applicability in forensic as well as clinical toxicology, the specific demands of both research fields were taken into account, and the method was thus validated for a low and high concentration range. For both serum and urine as sample matrix, the validation revealed good intraday and interday precisions, consistently ranging below 15% for the lowest and below 10% for elevated concentrations. Accuracy was likewise good and never exceeded 10%. Extraction recovery was excellent, ranging between 88.1 and 103.9% for SUX and SMC in both tested matrices. Matrix effects were significant, the otherwise optimized extraction and detection methods, however, allowed for a very satisfactory sensitivity of the described method: For serum, the limits of detection and quantitation were determined to be 1.9 and 6.0 ng/ml for SUX, as well as 2.5 and 8.6 ng/ml for SMC, respectively; for urine, the corresponding values were established to be 1.4 and 4.0 ng/ml (SUX), as well as 1.5 and 4.9 ng/ml (SMC).The presented method was successfully applied to authentic samples of two forensic cases investigated in the institute of forensic medicine in Bonn, allowing the diagnosis of SUX intoxications.