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Journal article
Feasibility and safety of repeated 23% hypertonic saline boluses for electrical impedance tomography contrast enhancement in anaesthetised horses
Frontiers in veterinary science, Vol.13, 1789443
2026
Abstract
Hypertonic saline (HS) has been used to enhance electrical impedance tomography (EIT) cardiac-related signals associated with pulmonary perfusion in other species, but its suitability and physiological effects in horses are unknown. This exploratory study aimed to determine whether intravenous administration of 100 mL of 23% HS produces a detectable change in thoracic impedance in anaesthetised horses, and to evaluate the physiological effects of repeated bolus administration. Six adult horses were anaesthetised twice using total intravenous anaesthesia. Hypertonic saline 23% was administered via a jugular catheter every 15 min (T15-T60). End-expiratory lung impedance (EELI), tidal impedance variation (TIV), heart rate (HR), and mean arterial pressure (MAP) were recorded at pre-injection, post-injection and end-sample timepoints. Plasma sodium (Na+) and chloride (Cl−) concentrations were measured before each injection and 15 minutes after the final injection (T75), while urinary fractional excretion (FE) was calculated at T15 and T75. Changes over time were assessed using repeated-measures ANOVA, and FE was compared using paired t-tests. Following HS injection, there was a significant decrease in EELI (p < 0.01), and unanticipated haemodynamic effects were observed, including a significant decrease in MAP (p < 0.01) and increase in HR (p < 0.01), with hypotension (MAP below 70 mmHg) occurring in 62% of post-injection measurements. TIV decreased significantly (p = 0.02), and alterations in breathing pattern occurred in 24/47 post-injection sample times, including transient tachypnoea, expiratory pauses, and crown-like breaths. Plasma Na+ and Cl− increased significantly over time (both p < 0.01), and FE of Na+ and Cl− increased between T15 and T75 (p = 0.01 and p = 0.02, respectively). Injection of 100 ml of 23% HS reduced EELI, supporting potential use for enhancing perfusion-related EIT signals. Repeated boluses produced clinically relevant decreases in MAP. Concurrent changes in TIV and breathing pattern may complicate interpretation of EIT-derived ventilation-perfusion relationships. Accordingly, repeated 23% HS boluses cannot currently be recommended for EIT contrast enhancement in horses. Further work is required to determine whether single-bolus or lower-concentration protocols provide adequate signal enhancement with less physiological disturbance.
Details
- Title
- Feasibility and safety of repeated 23% hypertonic saline boluses for electrical impedance tomography contrast enhancement in anaesthetised horses
- Authors/Creators
- Kieran Smith - Murdoch UniversityAnthea Raisis - Murdoch UniversityFernando Moreno-Martinez - Murdoch UniversityDavid Byrne - Murdoch UniversityMartina Mosing - University of Veterinary Medicine Vienna
- Publication Details
- Frontiers in veterinary science, Vol.13, 1789443
- Publisher
- Frontiers Media S.A.
- Identifiers
- 991005895761807891
- Copyright
- © 2026 Smith, Raisis, Moreno-Martinez, Byrne and Mosing.
- Murdoch Affiliation
- The Animal Hospital At Murdoch University; School of Veterinary Medicine
- Language
- English
- Resource Type
- Journal article
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