Electrical impedance tomography to measure lung ventilation distribution in healthy horses and horses with left‐sided cardiac volume overload

Background Left-sided cardiac volume overload (LCVO) can cause fluid accumulation in lung tissue changing the distribution of ventilation, which can be evaluated by electrical impedance tomography (EIT). Objectives To describe and compare EIT variables in horses with naturally occurring compensated and decompensated LCVO and compare them to a healthy cohort. Animals Fourteen adult horses, including university teaching horses and clinical cases (healthy: 8; LCVO: 4 compensated, 2 decompensated). Methods In this prospective cohort study, EIT was used in standing, unsedated horses and analyzed for conventional variables, ventilated right (VAR) and left (VAL) lung area, linear-plane distribution variables (avg-max VΔZLine, VΔZLine), global peak flows, inhomogeneity factor, and estimated tidal volume. Horses with decompensated LCVO were assessed before and after administration of furosemide. Variables for healthy and LCVO-affected horses were compared using a Mann-Whitney test or unpaired t-test and observations from compensated and decompensated horses are reported. Results Compared to the healthy horses, the LCVO cohort had significantly less VAL (mean difference 3.02; 95% confidence interval .77-5.2; P = .02), more VAR (−1.13; −2.18 to −.08; P = .04), smaller avg-max VΔZLLine (2.54; 1.07-4.00; P = .003) and VΔZLLine (median difference 5.40; 1.71-9.09; P = .01). Observation of EIT alterations were reflected by clinical signs in horses with decompensated LCVO and after administration of furosemide. Conclusions and Clinical Importance EIT measurements of ventilation distribution showed less ventilation in the left lung of horses with LCVO and might be useful as an objective assessment of the ventilation effects of cardiogenic pulmonary disease in horses

Thoracic Electrical Impedance Tomography—The 2022 Veterinary Consensus Statement

Electrical impedance tomography (EIT) is a non-invasive real-time non-ionising imaging modality that has many applications. Since the first recorded use in 1978, the technology has become more widely used especially in human adult and neonatal critical care monitoring. Recently, there has been an increase in research on thoracic EIT in veterinary medicine. Real-time imaging of the thorax allows evaluation of ventilation distribution in anesthetised and conscious animals. As the technology becomes recognised in the veterinary community there is a need to standardize approaches to data collection, analysis, interpretation and nomenclature, ensuring comparison and repeatability between researchers and studies. A group of nineteen veterinarians and two biomedical engineers experienced in veterinary EIT were consulted and contributed to the preparation of this statement. The aim of this consensus is to provide an introduction to this imaging modality, to highlight clinical relevance and to include recommendations on how to effectively use thoracic EIT in veterinary species. Based on this, the consensus statement aims to address the need for a streamlined approach to veterinary thoracic EIT and includes: an introduction to the use of EIT in veterinary species, the technical background to creation of the functional images, a consensus from all contributing authors on the practical application and use of the technology, descriptions and interpretation of current available variables including appropriate statistical analysis, nomenclature recommended for consistency and future developments in thoracic EIT. The information provided in this consensus statement may benefit researchers and clinicians working within the field of veterinary thoracic EIT. We endeavor to inform future users of the benefits of this imaging modality and provide opportunities to further explore applications of this technology with regards to perfusion imaging and pathology diagnosis

Exercise‐induced airflow changes in horses with asthma measured by electrical impedance tomography

Background Equine asthma (EA) causes airflow impairment, which increases in severity with exercise. Electrical impedance tomography (EIT) is an imaging technique that can detect airflow changes in standing healthy horses during a histamine provocation test. Objectives To explore EIT-calculated flow variables before and after exercise in healthy horses and horses with mild-to-moderate (MEA) and severe equine asthma (SEA). Animals Nine healthy horses 9 horses diagnosed with MEA and 5 with SEA were prospectively included. Methods Recordings were performed before and after 15 minutes of lunging. Absolute values from global and regional peak inspiratory (PIF, positive value) and expiratory (PEF, negative value) flows were calculated. Data were analyzed using a mixed model analysis followed by Bonferroni's multiple comparisons test to evaluate the impact of exercise and diagnosis on flow indices. Results Control horses after exercise had significantly lower global PEF and PIF compared to horses with SEA (mean difference [95% confidence interval, CI]: 0.0859 arbitrary units [AU; 0.0339-0.1379], P < .001 and 0.0726 AU [0.0264-0.1188], P = .001, respectively) and horses with MEA (0.0561 AU [0.0129-0.0994], P = .007 and 0.0587 AU [0.0202-0.0973], P = .002, respectively). No other significant differences were detected. Conclusions and Clinical Importance Electrical impedance tomography derived PIF and PEF differed significantly between healthy horses and horses with SEA or MEA after exercise, but not before exercise. Differences between MEA and SEA were not observed, but the study population was small

Damages caused by hurricane Irma in the human-degraded mangroves of Saint Martin (Caribbean)

International audienceIn early September 2017, Irma was the most powerful hurricane that struck the northern Caribbean over the last 100 years. In the 21st century, the stronger types of tropical cyclones will likely increase in frequency due to the climate change and internal climate variability. Lessons to anticipate the response of mangroves to this intensification can be learned from this extreme event. Here, we analysed damages caused in mangrove forests of the Saint Martin Island. Mangroves of this island were previously degraded due to historic human pressures and recent over-urbanisation. Forest inventories and time series of very high resolution satellite images revealed that approximately 80% of the mangrove area was damaged by the hurricane. Results highlighted distinct rates of forest recovery. Early and rapid recoveries were largely observed in most study sites. However, some mangroves were still unable to recover fourteen months after the disturbance. The human-induced degradation of the ecosystem prior to the hurricane is hypothesised to be the main factor controlling the absence of forest recovery. We suggest that human-degraded mangroves will be weakened in the face of such extreme events. We advocate to preserve and restore mangroves in order to guarantee all the valuable ecosystem services they provided

Damages caused by hurricane Irma in the human-degraded mangroves of Saint Martin (Caribbean)

AbstractIn early September 2017, Irma was the most powerful hurricane that struck the northern Caribbean over the last 100 years. In the 21st century, the stronger types of tropical cyclones will likely increase in frequency due to the climate change and internal climate variability. Lessons to anticipate the response of mangroves to this intensification can be learned from this extreme event. Here, we analysed damages caused in mangrove forests of the Saint Martin Island. Mangroves of this island were previously degraded due to historic human pressures and recent over-urbanisation. Forest inventories and time series of very high resolution satellite images revealed that approximately 80% of the mangrove area was damaged by the hurricane. Results highlighted distinct rates of forest recovery. Early and rapid recoveries were largely observed in most study sites. However, some mangroves were still unable to recover fourteen months after the disturbance. The human-induced degradation of the ecosystem prior to the hurricane is hypothesised to be the main factor controlling the absence of forest recovery. We suggest that human-degraded mangroves will be weakened in the face of such extreme events. We advocate to preserve and restore mangroves in order to guarantee all the valuable ecosystem services they provided.</jats:p