Methodology for field-gas sampling transport and analysis in the laboratory of gas embolism found in stranded cetaceans

Abstract

Several atypical mass standings of beaked whales have occurred in spatio-temporal concordance with military maneuvers world-wide. Gas-bubble associated lesions and fat embolism suggesting a decompression-like disease has been found on the strandings in the Canary Islands in 2002. This paper raised an important public controversy, requiring further investigations including an analysis of the composition of the gas in the bubbles. Gas composition analysis might elucidate some of the questions raised by the gas-bubble findings. We propose a methodology for in situ extraction, transport and later analysis on the laboratory. Taking in mind transport and possible non-comfortable stranding sites, methodology has been developed to remain as simple as possible and with non-breakable materials whenever this was possible. Gas samples from cavities are sampled with a double pointed needle coupled directly to a vacutainer. Bubbles are extracted with a plastic-insulin syringe, and gas from heart is extracted and separated from the blood with the use of a home-designed aspirometer. All samples are storaged in vacutainers at room temperature. Analyses of permanent gases and hydrocarbons up to 4 carbons are done by gas chromatography. Atmospheric air pollution has been avoided to the maximum possible extent along all the procedure, and correction factors have been introduced into calculations. This methodology has been tested for adjustments in 41 cetaceans that stranded in the canaries coast between 2006 and 2008. A total of 132 gas samples were analysed. We present a new methodology that enables in situ gas sampling of stranded cetaceans and gas analysis base lines that contributes to identify the gas composition.