Assessment of distribution of ventilation and regional lung compliance by electrical impedance tomography in anaesthetized horses undergoing alveolar recruitment manoeuvres.
Abstract: To examine changes in the distribution of ventilation and regional lung compliances in anaesthetized horses during the alveolar recruitment manoeuvre (ARM). Methods: Experimental study in which a series of treatments were administered in a fixed order on one occasion. Methods: Five adult Warmblood horses. Methods: Animals were anaesthetized (xylazine, midazolam-ketamine, isoflurane), placed in dorsal recumbency and ventilated with 100% oxygen using peak inspiratory pressure (PIP) and positive end-expiratory pressure (PEEP) of 20 cmHO and 0 cmHO, respectively. Thoracic electrical impedance tomography (EIT), spirometry and routine anaesthesia monitoring were performed. At 90 minutes after induction of anaesthesia, PIP and PEEP were increased in steps of 5 cmHO to 50 cmHO and 30 cmHO, respectively, and then decreased to baseline values. Each step lasted 10 minutes. Data were recorded and functional EIT images were created using three breaths at the end of each step. Arterial blood samples were analysed. Values for left-to-right and sternal-to-dorsal centre of ventilation (COV), lung compliances and Bohr dead space were calculated. Results: Distribution of ventilation drifted leftward and dorsally during recruitment. Mean±standard deviation (SD) values at baseline and highest airway pressures, respectively, were 49.9±0.7% and 48.0±0.6% for left-to-right COV (p=0.009), and 46.3±2.0% and 54.6±2.0% for sternal-to-dorsal COV (p=0.0001). Compliance of dependent lung regions and PaO increased, whereas compliance of non-dependent lung regions decreased during ARM and then returned to baseline (p<0.001). Bohr dead space decreased after ARM (p=0.007). Interestingly, PaO correlated to the compliance of the dependent lung (r=0.71, p<0.001). Conclusions: The proportion of tidal volume distributed to dependent and left lung regions increased during ARM, presumably as a result of opening atelectasis. Monitoring compliance of the dependent lung with EIT may substitute PaO measurements during ARM to identify an optimal PEEP.
Copyright © 2017 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.
Publication Date: 2017-01-12 PubMed ID: 28237681DOI: 10.1016/j.vaa.2016.03.001Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
- Anesthesia
- Clinical Findings
- Clinical Pathology
- Clinical Study
- Diagnosis
- Diagnostic Technique
- Disease Diagnosis
- Disease Treatment
- Equine Diseases
- Equine Health
- Experimental Methods
- Horses
- Imaging Techniques
- Lung Health
- Pathophysiology
- Physiology
- Respiratory Health
- Veterinary Medicine
- Veterinary Research
- Warmblood Horses
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
The study investigated how the distribution of ventilation and regional lung compliance in horses changes during an alveolar recruitment manoeuvre (ARM), a technique applied while a horse is under anesthesia. The researchers identified shifts in oxygen distribution in the lung and changes in lung elasticity, concluding that the methodology used in the study could potentially replace traditional oxygen measurements during ARMs.
Methodology
- Five adult Warmblood horses were anesthetized and placed on their backs (dorsal recumbency). They were ventilated with 100% oxygen using specified pressure parameters.
- Thoracic electrical impedance tomography (EIT), spirometry and standard anesthesia monitoring were conducted.
- Oxygen distribution and regional lung compliance, which marks the lungs’ ability to stretch and expand, were monitored and recorded using EIT.
- Then, the researchers increased and then reduced the airway pressures in given stages and documented the responses of the animals for each stage.
- The distribution of ventilation between the left and right lung, as well as from the chest (sternal) to the back (dorsal), was calculated. This was done through Centre of Ventilation (COV) measurements.
- Lung compliances and Bohr dead space, which represents the volume of air in which gas exchange does not take place, were also computed.
Results
- Data showed a shift in the distribution of ventilation towards the left and back (dorsal) of the lungs during ARM.
- Compliance of dependent lung regions improved and partial pressure of arterial oxygen (PaO) increased.
- The opposite effect was noted in non-dependent lung parts, with their compliance decreasing during ARM, before eventually returning to baseline.
- Dead space was observed to decrease following ARM.
- A correlation was found between the dependent lung compliance and PaO.
- The conclusions drawn indicated an increased distribution of tidal volume to both the dependent and left lung regions during ARM, triggering the opening of collapsed lung regions (atelectasis).
Conclusions
- The findings suggest that monitoring lung compliance using EIT could potentially substitute for measuring PaO during ARM, providing a means to identify optimal Positive End-Expiratory Pressure (PEEP).
Cite This Article
APA
Ambrisko TD, Schramel J, Hopster K, Kästner S, Moens Y.
(2017).
Assessment of distribution of ventilation and regional lung compliance by electrical impedance tomography in anaesthetized horses undergoing alveolar recruitment manoeuvres.
Vet Anaesth Analg, 44(2), 264-272.
https://doi.org/10.1016/j.vaa.2016.03.001 Publication
Researcher Affiliations
- Anaesthesiology and Perioperative Intensive Care Medicine, Department for Companion Animals and Horses, University of Veterinary Medicine, Vienna, Austria. Electronic address: tambrisko@hotmail.com.
- Anaesthesiology and Perioperative Intensive Care Medicine, Department for Companion Animals and Horses, University of Veterinary Medicine, Vienna, Austria.
- Clinic for Horses, University of Veterinary Medicine, Hannover, Germany.
- Clinic for Horses, University of Veterinary Medicine, Hannover, Germany.
- Anaesthesiology and Perioperative Intensive Care Medicine, Department for Companion Animals and Horses, University of Veterinary Medicine, Vienna, Austria.
MeSH Terms
- Animals
- Electric Impedance
- Horses
- Lung Compliance / physiology
- Positive-Pressure Respiration / methods
- Positive-Pressure Respiration / veterinary
- Pulmonary Alveoli / physiology
- Respiration
- Tidal Volume
- Tomography / methods
- Tomography / veterinary
Citations
This article has been cited 11 times.- Brandly JE, Midon M, Douglas HF, Hopster K. Flow-controlled expiration reduces positive end-expiratory pressure requirement in dorsally recumbent, anesthetized horses. Front Vet Sci 2023;10:1135452.
- Bajon F, Gauthier V. Management of refractory hypoxemia using recruitment maneuvers and rescue therapies: A comprehensive review. Front Vet Sci 2023;10:1157026.
- Andrade FSRM, Ambrósio AM, Rodrigues RR, Faccó LL, Gonçalves LA, Garcia Filho SG, Dos Santos RT, Rossetto TC, Pereira MAA, Fantoni DT. The optimal PEEP after alveolar recruitment maneuver assessed by electrical impedance tomography in healthy horses. Front Vet Sci 2022;9:1024088.
- Ambrósio AM, Sanchez AF, Pereira MAA, Andrade FSRM, Rodrigues RR, Vitorasso RL, Moriya HT, Fantoni DT. Assessment of Regional Ventilation During Recruitment Maneuver by Electrical Impedance Tomography in Dogs. Front Vet Sci 2021;8:815048.
- Dupont J, Serteyn D, Sandersen C. Prolonged Recovery From General Anesthesia Possibly Related to Persistent Hypoxemia in a Draft Horse. Front Vet Sci 2018;5:235.
- Mosing M, Böhm SH, Rasis A, Hoosgood G, Auer U, Tusman G, Bettschart-Wolfensberger R, Schramel JP. Physiologic Factors Influencing the Arterial-To-End-Tidal CO(2) Difference and the Alveolar Dead Space Fraction in Spontaneously Breathing Anesthetised Horses. Front Vet Sci 2018;5:58.
- Zitzmann A, Strübing A, Reuter DA, Waldmann A, Böhm SH, Müller-Graf F. Enhancing tidal volume estimation from electrical impedance tomography (EIT) by applying human anthropometric information. J Clin Monit Comput 2026 Feb;40(1):93-101.
- Lippuner R, Pellaud C, Huber M, Greif R, Disma N, Riva T, Fuchs A, Riedel T. Efficacy of a lung recruitment manoeuvre in children undergoing general anaesthesia with a supraglottic airway. Br J Anaesth 2025 Nov;135(5):1537-1542.
- Román Durá B, Dunham O, Grulke S, Salciccia A, Dupont J, Sandersen C. A Retrospective Study on Pre- and Intraoperative Predictors on the Recovery Quality of Horses After General Anesthesia. Vet Sci 2025 Mar 11;12(3).
- Ambrósio AM, Fantoni DT. Editorial: Mechanical ventilation in anesthesia and critical care animal patients, volume II. Front Vet Sci 2024;11:1402629.
- Byrne DP, Keeshan B, Hosgood G, Adler A, Mosing M. Comparison of electrical impedance tomography and spirometry-based measures of airflow in healthy adult horses. Front Physiol 2023;14:1164646.
Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists
