Equine Asthma Syndrome (EAS) is a common respiratory problem that affects horses of any age. In the severe EAS form (historically referred to as recurrent airway obstruction or RAO) the diagnosis, based mainly on history and clinical signs, it is definitively confirmed by the cytological examination of the bronchoalveolar lavage (BAL), also very useful in monitoring lower airway inflammation in response to environmental management and medication. Cytocentrifugated preparation is usually the staging method for the BAL cytological interpretation. To evaluate whether the BAL cytology in horses with severe EAS under different environmental conditions and before and after treatment can undergo significant changes, and at the same time to investigate whether in the cytological evaluation of the BAL there are interpretative differences between two methods of smear preparation of the collected fluid, a study was carried out on a series of BAL samples (n=48) collected in 8 withdrawals from 6 EAS-affected horses subjected to process exacerbation through environmental stimuli and then to pharmacological treatment. Each BAL fluid collected was equally divided into duplicate portions: one set up by cytocentrifugation and one by sediment from simple centrifugation. The cytological examination revealed any significant difference between the EAS-affected horses in all experimental phases (asymptomatic, early exacerbation phase, late exacerbation phase, and remission phase). Diagnostic interpretive comparison between the two BAL preparations then showed no significant differences in results, suggesting how they can be used indifferently in the evaluation of BAL under conditions of airway inflammation in the horse. Thus, the concentrated smear preparation appears to be an equally diagnostically useful method in conditions where there is no possibility of using an appropriate cytocentrifuge.

The aim of this prospective, randomized, clinical study was to evaluate the use of the pleth variability index (PVi) to guide the rate of intra-operative fluid therapy as compared with a traditional fixed fluid rate approach in ASA 1-2 dogs undergoing surgery. Twenty-seven dogs meet the inclusion criteria and were randomly assigned to conventional fluid management group (CFM, n = 12) or PVi-guided group (PVi, n = 15). The CFM group received a fixed rate of 5 ml kg-1 h-1 of crystalloid solution, while in the PVi group the rate was continuously adjusted based on PVi: PVi < 14% = 3 ml kg-1 h-1; 14% ≤ PVi ≥ 20% = ml kg-1 h-1; PVi > 20% = 15 ml kg-1 h-1. Hypotension (MAP < 65 mmHg) was managed in CFM with maximum two fluid boluses (5 ml kg-1 in 10 minutes) and in case of no response dobutamine (1-3 mcg kg-1 min-1) was administered. In the PVi group treatment of hypotension was similar except when PVi > 14% when dobutamine was directly initiated. The total fluid amount was significantly lower in PVI group (0.056 ± 0.027 ml kg-1 min-1) vs. CFM group (0.132 ± 0.115 ml kg-1 min-1), and hypotension incidence was lower (p = 0.023) in PVi group (0%) vs. CFM group (41%). Mean arterial pressure (MAP) was significantly higher during surgery in the PVi group. Dobutamine was never administered in both groups. Preliminary data suggest that PVi may be considered a potential target to guide fluid therapy in dogs; larger studies are needed, especially in cases of cardiovascular instability.