A Survey on the Use of Spirometry in Small Animal Anaesthesia and Critical Care

The objective was to document the use of spirometry and ventilation settings in small animal anaesthesia and intensive care through a descriptive, open, online, anonymous survey. The survey was advertised on social media and via email. Participation was voluntary. The google forms platform was used. It consisted of eight sections in English: demographic information, use of spirometry in spontaneously ventilating/mechanically ventilated dogs, need for spirometry, equipment available and calibration status, ventilation modes, spirometry displays, compliance (CRS) and resistance (RRS) of the respiratory system. Simple descriptive analyses were applied. There were 128 respondents. Respondents used spirometry more in ventilated dogs than during spontaneous breathing. Over 3/4 of the respondents considered spirometry essential in “selected” (43%) or “most” cases (33%). Multiple devices and technologies were used. The majority of the respondents were not directly involved in or informed about the calibration of their equipment. Of all displays, pressure-volume loops were the most common. Values of CRS and RRS were specifically monitored in more than 50% of cases by 44% of the respondents only. A variety of ventilation modes was used. Intensivists tend to use smaller VT than anaesthetists. More information on reference intervals of CRS and RRS and technical background on spirometers is required

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

Comparison of electrical impedance tomography and spirometry-based measures of airflow in healthy adult horses

Electrical impedance tomography (EIT) is a non-invasive diagnostic tool for evaluating lung function. The objective of this study was to compare respiratory flow variables calculated from thoracic EIT measurements with corresponding spirometry variables. Ten healthy research horses were sedated and instrumented with spirometry via facemask and a single-plane EIT electrode belt around the thorax. Horses were exposed to sequentially increasing volumes of apparatus dead space between 1,000 and 8,500 mL, in 5–7 steps, to induce carbon dioxide rebreathing, until clinical hyperpnea or a tidal volume of 150% baseline was reached. A 2-min stabilization period followed by 2 minutes of data collection occurred at each timepoint. Peak inspiratory and expiratory flow, inspiratory and expiratory time, and expiratory nadir flow, defined as the lowest expiratory flow between the deceleration of flow of the first passive phase of expiration and the acceleration of flow of the second active phase of expiration were evaluated with EIT and spirometry. Breathing pattern was assessed based on the total impedance curve. Bland-Altman analysis was used to evaluate the agreement where perfect agreement was indicated by a ratio of EIT:spirometry of 1.0. The mean ratio (bias; expressed as a percentage difference from perfect agreement) and the 95% confidence interval of the bias are reported. There was good agreement between EIT-derived and spirometry-derived peak inspiratory [−15% (−46–32)] and expiratory [10% (−32–20)] flows and inspiratory [−6% (−25–18)] and expiratory [5% (−9–20)] times. Agreement for nadir flows was poor [−22% (−87–369)]. Sedated horses intermittently exhibited Cheyne-Stokes variant respiration, and a breath pattern with incomplete expiration in between breaths (crown-like breaths). Electrical impedance tomography can quantify airflow changes over increasing tidal volumes and changing breathing pattern when compared with spirometry in standing sedated horses

Evaluation of Centre of Ventilation (CoV) during three different ventilation conditions

The EIT-based Centre of Ventilation (CoV) within the lungs was evaluated at baseline and 10 minutes after applying three ventilation conditions: (1) zero endexpiratory pressure (ZEEP), (2) 5 cmH2O of PEEP without a recruitment maneuvre (RM) and (3) after a RM. A significant dorsal shift of the CoV was seen for the RM, but not for the other two conditions

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

Anaesthetic management of a 1-month old puppy undergoing lateral thoracotomy for vascular ring anomaly correction

A 1-month-old male flat-coated retriever was anaesthetized for correction of oesophageal constriction caused by a vascular ring anomaly. Anaesthesia was uneventfully induced with intravenous fentanyl, diazepam, and propofol and maintained with isoflurane in oxygen and air. An intercostal block with bupivacaine and lidocaine was performed, and additional analgesia with an infusion of fentanyl was provided. Fluid therapy consisted in 5% glucose in lactated Ringer’s solution and hetastarch 6%, which proved adequate to maintain normoglycemia and normovolemia. A lateral thoracotomy was performed, and the ligamentum arteriosum was ligated. Intraoperatively, heart rate (HR) varied between 120 and 180 beats min−1 without accompanying changes in blood pressure. No arrhythmias were observed or bleeding occurred. The dog recovered uneventfully. Postoperative analgesia consisted in fentanyl infusion adjusted to the patient's requirement and metamizol. This paper describes for the first time the use of balanced anaesthesia and multimodal analgesia in a paediatric dog undergoing thoracotomy

Lebensgefährliche Hyperkaliämie durch ischämische Muskelnekrose bei einer Katze. Fallbeschreibung und Literaturübersicht

Objective: Description of a cat with ischemic muscle necrosis that suffered from cardiopulmonary arrest due to hyperkalemia. Pathogenesis, clinical signs and therapy of ischemic muscle necrosis are discussed and possible causes, symptoms and treatment of hyperkalemia are shown. Material and methods: case report of a four-year-old male castrated domestic shorthair cat. Results: The cat was successfully resuscitated and hyperkalemia was treated with different treatment modalities. Conclusion: Ischemic muscle necrosis can lead to severe live-threatening hyperkalemia which has to be anticipated, monitored and treated adequately. Aggressive fluid therapy might be responsible for a higher risk of hyperkalemia in predisposed cases. Clinical relevance: Potassium concentrations and acid-base disturbances must be closely monitored in patients with ischemic muscle necrosisGegenstand und Ziel: Beschreibung einer Katze mit Atem- und Kreislaufstillstand verursacht durch Hyperkaliämie nach ischämischer Muskelnekrose. Pathogenese, Klinik, Komplikationen und Therapie von ischämischer Muskelnekrose werden diskutiert und mögliche Ursachen, Symptome und Therapiemöglichkeiten einer Hyperkaliämie beschrieben. Material und Methoden: Fallbericht einer vierjährigen, männlich-kastrierten Hauskatze. Ergebnisse: Die Katze wurde erfolgreich reanimiert und die Hyperkaliämie ließ sich mittels verschiedener Therapieansätze normalisieren. Der Kater konnte nach Hause entlassen werden. Schlussfolgerungen: Bei ischämischer Muskelnekrose kann es während der Reperfusionsphase zu einer lebensgefährlichen Hyperkaliämie kommen, die überwacht und entsprechend therapiert werden muss. Bei aggressiver Flüssigkeitstherapie ist das Risiko einer Kalium- und Toxinfreisetzung aus dem ischämischen Muskel unter Umständen größer. Klinische Relevanz: Bei ischämischer Muskelnekrose sollten Kaliumkonzentration und Säure-Basen-Haushalt regelmäßig überwacht werden

Flüssigkeitstherapie beim Kleintier - eine Übersicht

Dieser Artikel beschreibt die adäquate Anwendung von Kristalloiden und Kolloiden beim Kleintier. Dabei werden praktische Überlegungen für die Wahl der korrekten Infusionslösung, die Verabreichungsart und die Infusionsrate diskutiert