TY - JOUR T1 - Severe airway response associated with anaphylactic shock in allergic Brown Norway rats JF - European Respiratory Journal JO - Eur Respir J VL - 38 IS - Suppl 55 SP - p2037 AU - Grégoire Barthel AU - Bruno Demoulin AU - Chantal Montémont AU - Feng Zheng AU - Julien Davidson AU - François Marchal AU - Mertes Paul-Michel Y1 - 2011/09/01 UR - http://erj.ersjournals.com/content/38/Suppl_55/p2037.abstract N2 - Background: Bronchospasm may occur as part of the early response to anaphylaxis on induction of anaesthesia in humans. However, little data are available on the changes in respiratory mechanics occurring in animal models of anaphylactic shock.The aim of the study was to delineate the respiratory mechanical impedance response to ovalbumin (OVA)-induced anaphylaxis in Brown Norway rats.Methods: Anesthetized, tracheostomized, paralysed and mechanically ventilated ovalbumin-sensitized male Brown Norway rats were randomly allocated to intravenous OVA (n=11) or vehicle (n=7). The respiratory resistance (Rrs) and reactance (Xrs) were measured at 20 Hz using the forced oscillation technique.Results: Allergic rats showed consistent and dramatic increase in respiratory impedance. The peak Rrs response - almost a threefold increase - occurred 224±49 sec after OVA injection (from 51.2±7.4 hPa.s/L to 140.9±57.5 hPa.s/L, p < 0.001). This was roughly paralleled by a significant decrease in Xrs (from –10.8±4.7 hPa.s/L to –50.1±28.5 hPa.s/L, p < 0.003). The control group showed little change after vehicle injection.Conclusions: Severe airway obstruction occurs with anaphylactic shock in allergic Brown-Norway rats. The associated decrease in Xrs indicates an increase in apparent respiratory elastance (e.g. with lung vascular engorgement or pulmonary oedema) and/or inhomogeneity of mechanical time constants within the lung from heterogeneous bronchoconstriction. Data from this animal model emphasize the significance of respiratory abnormalities in humans during anaphylactic shock. ER -