Lung Function In Horses Research Articles

Effects of soaked hay on lung function and airway inflammation in horses with severe asthma.

Reducing inhaled dust particles improves lung function in horses with severe asthma. Soaked hay is commonly used by owners, but its efficacy in improving lung function and inflammation has not been documented. To measure the effects of soaked hay and alfalfa pellets in horses with severe asthma. Ten adult horses with severe asthma from a research colony. Prospective controlled trial. Horses in clinical exacerbation were housed indoors and allocated to be fed either soaked hay (n = 5) or alfalfa pellets (n = 5) for 6 weeks. Soaked hay was immersed for 45 minutes and dried out hay was discarded between meals. Pulmonary function and clinical scores were measured before and after 2, 4, and 6 weeks. Tracheal mucus scores and bronchoalveolar lavages were performed before and after 6 weeks. Lung function was analyzed with a linear mixed model using log-transformed data. Lung resistance decreased from (median (range)) 2.47 (1.54-3.95) to 1.59 (0.52-2.10) cmH2 O/L/s in the pellets group and from 1.89 (1.2-3.54) to 0.61 (0.42-2.08) cmH2 O/L/s in the soaked hay group over the 6-week period for an average difference of 1.06 cmH2 O/L/s for pellets (95% confidence interval [95% CI]: 0.09-2.04, P = .03, not significant after correction) and 1.31 cmH2 O/L/s for soaked hay (95% CI: -0.23 to 2.85, P < .001, significant). Soaked hay can control airway obstruction in horses with severe asthma. The strict protocol for soaking and discarding dried-out hay in this study could however be considered too great of an inconvenience by owners.

A portable fan-based device for evaluating lung function in horses by the forced oscillation technique

Objective. The assessment of lung mechanics in horses is nowadays based on invasive methods that may require sedation. The forced oscillation technique (FOT) allows the non-invasive assessment of respiratory mechanics during spontaneous breathing, but current devices are complex, cumbersome, expensive, and difficult to be applied in horses. Approach. We developed a portable FOT device based on a novel approach in which the pressure waveforms are generated by a servo-controlled ducted fan. This new approach allows the design of devices that are more sturdy, compact, and portable compared to already existing approaches. The prototype includes 1) a small microcontroller-based electronic board for controlling the fan and measuring flow and pressure and 2) an optimized data processing algorithm. Main results. This device provides a maximum error of 0.06 cmH2O·s/L and 0.15 cmH2O·s/L in measuring respiratory resistance and reactance during in-vitro validation. A pilot study was also performed on three healthy horses and three horses with severe equine asthma (SEA) and it demonstrated good tolerability and feasibility of the new device. Total respiratory system resistance (R rs) and reactance (X rs) significantly differed (p < 0.05) between groups. At 5 Hz, R rs was 0.66 ± 0.02 cmH2O·s/L and 0.94 ± 0.07 cmH2O·s/L in healthy and in SEA, respectively. X rs 0.38 ± 0.02 cmH2O·s/L and −0.27 ± 0.05 cmH2O·s/L. Significance. This novel approach for applying FOT allowed the development of a small, affordable, and portable device for the non-invasive evaluation of respiratory mechanics in spontaneously breathing horses, providing a useful new tool for improving veterinary respiratory medicine. Moreover, our results provide supporting evidence of the value of this novel approach for developing portable FOT devices also for applications in humans.

Is inhaled immunotherapy more effective than environmental management when treating equine asthma?

PICO question&#x0D; In horses with severe equine asthma syndrome, is inhaled immunotherapy compared to environmental reduction of allergen exposure more effective in disease modification?&#x0D; &#x0D; Clinical bottom line&#x0D; Category of research question&#x0D; Treatment&#x0D; The number and type of study designs reviewed&#x0D; 12 papers were critically reviewed. Nine clinical trials; one crossover study; one split-plot design study; and one cross-sectional study&#x0D; Strength of evidence&#x0D; Low&#x0D; Outcomes reported&#x0D; Four studies found inhaled immunotherapy to improve the clinical signs associated with equine asthma and the lung function of horses with asthma. Three papers found environmental modification by improved lung function and the clinical signs associated with equine asthma but two studies provide moderate evidence that environmental management alone is insufficient to permanently cure asthma&#x0D; Conclusion&#x0D; There is a low level of evidence to support the use of inhaled immunotherapy as a treatment for equine asthma&#x0D; &#x0D; How to apply this evidence in practice&#x0D; The application of evidence into practice should take into account multiple factors, not limited to: individual clinical expertise, patient’s circumstances and owners’ values, country, location or clinic where you work, the individual case in front of you, the availability of therapies and resources.&#x0D; Knowledge Summaries are a resource to help reinforce or inform decision making. They do not override the responsibility or judgement of the practitioner to do what is best for the animal in their care.&#x0D; &#x0D;

Intra-articular triamcinolone acetonide improves lung function in horses with severe asthma.

Locally administered corticosteroids are commonly used to treat joint diseases in sport and racehorses. As they are also the most potent drugs for the treatment of equine asthma, we hypothesised that the intra-articular corticosteroids used to treat joint diseases also improve the lung function in horses with severe asthma, thus potentially delaying the diagnosis of this common lung condition. To compare the effects of intra-articular (IA) and intramuscular (IM) triamcinolone acetonide (TA) on lung function in horses with severe asthma. Randomised and controlled experiment on asthma-prone research animals. Horses with severe asthma in clinical exacerbation were given either 20mg of TA in both tarsocrural joints (n=5; 40mg/horse) or 40mg of TA intramuscularly (n=5). Lung function and TA serum concentrations were measured weekly for 35days. TA serum concentrations were also evaluated on day 3. The pulmonary resistance (RL ) and elastance (EL ) values decreased by day 7 in the IA group (P<0.0001 and P=0.003, respectively) and by day 14 in the IM group (P=0.002 and 0.03, respectively). Lung function was improved up to days 21 and 28 in the IA and IM groups, respectively, when compared with baseline. TA serum levels were below the quantification limit (100pg/ml) for 4 and 3 of the 5 horses in the IA and IM groups, respectively, on day7. The area under the curve for RL , EL and the serum concentrations of TA were similar in both groups. The response of horses with severe asthma might differ from that of high-performance horses with mild/moderate asthma. Intra-articular administration of TA improves lung function in horses with severe asthma, an effect that persists when TA serum concentration is below the quantification level that is employed as a threshold by the International Association of Racing Commissioners.

Effects of magnesium sulfate infusion on clinical signs and lung function of horses with severe asthma.

OBJECTIVE To evaluate whether MgSO4 solution administered IV would improve the clinical signs and lung function of horses with severe asthma and potentiate the effects of salbutamol inhalation in those horses. ANIMALS 6 adult horses with severe asthma. PROCEDURES Asthmatic horses were used in 3 crossover design experiments (6 treatments/horse). Clinical scores for nasal flaring and the abdominal component associated with breathing and lung function were determined before and after administration of salbutamol (800 μg, by inhalation), MgSO4 solution (2.2 mg/kg/min, IV, over 20 minutes), and combined MgSO4-salbutamol treatment. The data were collected during experimental procedures to assess salbutamol inhalation versus mock inhalation, MgSO4 infusion versus infusion of saline (NaCl) solution (adjusted to the same osmolarity as the MgSO4 solution), and the combined MgSO4-salbutamol treatment versus salbutamol inhalation alone. RESULTS Infusion of MgSO4 significantly improved clinical scores when administered alone or in combination with salbutamol inhalation. With the combination treatment, lung function improved, albeit not significantly. Tidal volume also increased following combined MgSO4-salbutamol treatment. Salbutamol alone significantly improved lung function, whereas saline solution administration and a mock inhalation procedure had no effect on the studied variables. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that MgSO4 infusion alone or in combination with salbutamol inhalation improved the clinical signs of severely asthmatic horses. The effects of MgSO4 were not associated with significant lung function improvement, which suggested that the changes observed were attributable to alterations in the horses' breathing patterns. Infusion of MgSO4 solution at the studied dose offers little advantage over currently used medications for the treatment of severe equine asthma.

Effects ofN‐Butylscopolammonium Bromide on Lung Function in Horses with Recurrent Airway Obstruction

Equine recurrent airway obstruction (RAO) is characterized by airway inflammation, bronchoconstriction, and increased mucus production in the airways. Anticholinergic drugs like atropine induce bronchodilatation and rapid improvement in lung function. N-butylscopolammonium bromide (NBB) is an anticholinergic drug used to relieve spasmodic colic in horses, but its effect on airway smooth muscle is unknown. To evaluate the effect of NBB on clinical signs and lung function of RAO-affected horses. Nine horses diagnosed with RAO. Double-blind, placebo-controlled, randomized crossover trial. Horses were challenged with moldy hay until a maximum change in transpulmonary pressure (∆P(L) (max) ) > 15 cm H(2) O was achieved. NBB (0.3 mg/kg) or placebo (0.9% saline) was administered IV. Clinical scores and lung function were recorded at baseline and then periodically after treatment administration. Horses were allowed a 6-week washout before administration of opposite treatments. Clinical score at 10 and 30 minutes (8.7 ± 2.8 and 8.7 ± 3.2, respectively) after NBB administration was significantly lower than baseline (10.8 ± 2.4). NBB administration resulted in a significant decrease in ∆P(L) (max) (baseline: 35.1 ± 6.9 cm H(2) O) starting 2 minutes after administration (16.3 ± 6.6 cmH(2) O) with a maximum decline observed at 10 minutes (13.5 ± 7.1 cm H(2) O). ∆P(L) (max) values between 60 and 120 minutes after NBB administration were not different from placebo. N-butylscopolammonium bromide is a potent bronchodilator, reaching maximum effect 10 minutes after intravenous administration. This effect dissipates within 1 hour of drug administration.

Efficacy and Safety of Sound Wave Treatment of Recurrent Airway Obstruction in Horses

One proposed nonmedical therapy for recurrent airway obstruction (RAO) in horses is a handheld acoustic device that propels sound waves from the nose down the tracheobronchial tree where it is intended to dislodge mucous and relax bronchospasm, permitting clearance of mucoid secretions. To evaluate the effectiveness and safety of this device when used as per the manufacturer's recommendations as a treatment for RAO. Nine adult horses previously diagnosed with RAO. Prospective, cross-over clinical trial. Horses were exposed to a dusty environment until airway obstruction developed as defined by standard lung mechanics (SLM). Horses were randomly assigned to receive either acoustic therapy or a sham treatment for 4 weeks while being maintained in this environment. Horses were evaluated by clinical scores, SLM, and forced expiration regularly for 4 weeks. The opposite treatment was administered after a washout period. Seven horses received the treatment; 9 received the sham. There were no changes (P>.05) in clinical score, maximal change in transpulmonary pressure (ΔPLmax), lung resistance (RL), or the forced expiratory flow rate averaged over the last 75-95% of expiration (FEF75-95%) over the study period. The device was determined to be safe, although several minor adverse effects were noted, including head tossing, coughing, and chewing during treatment. Treatment with this device did not improve clinical signs or lung function in horses with RAO kept in a dusty environment. Currently accepted treatments, including environmental management and medical therapy, should be recommended.

Effects of the bronchoalveolar lavage procedure on lung function in horses with clinical exacerbation of recurrent airway obstruction

To evaluate whether bronchoalveolar lavage (BAL) alters respiratory mechanics of horses with recurrent airway obstruction (ie, heaves) over a 48-hour period. 6 horses affected with heaves. Horses were subjected to a complete BAL procedure, which included sedation with xylazine and butorphanol, intratracheal administration of lidocaine, and instillation and aspiration of two 250-mL boluses of saline (0.9% NaCl) solution through an endoscope (study 1). To evaluate the effects of saline solution, horses were subjected to the same procedure without saline solution instillation and aspiration (study 2). Lastly, the endoscope was similarly introduced into the lower airways, without sedation or saline instillation and aspiration (study 3). Respiratory mechanics were performed at baseline (time 0) and at 3, 6, 12, 24, and 48 hours after each procedure. In study 1, BAL induced a significant decrease in pulmonary resistance lasting up to 6 hours. This may have resulted from clearance of mucus in large airways. We also observed a significant increase in lung elastance and transpulmonary pressure at 12 hours after BAL in all 3 studies, which may be attributed to a circadian effect. Our results indicate that the temporal effects of BAL procedures on lung mechanics should be taken into account when designing research protocols involving horses with heaves. Future studies should address the immediate effects of BAL on lung function.

Relationship between clinical signs and lung function in horses with recurrent airway obstruction (heaves) during a bronchodilator trial.

During a trial to determine the dose response to the beta2-adrenergic agonist pirbuterol, we judged the severity of airway obstruction by use of a clinical scoring system and compared this to objective data obtained by quantitative measures of lung function. Six horses affected by recurrent airway obstruction were used in this trial. Four hundred and sixty-eight measurements of lung function and clinical scores were obtained from 13 measurement periods when horses received each of 6 doses of pirbuterol. Scores of 1-4 were assigned to degree of nasal flaring and abdominal effort and summed for a total score. The veterinarian scoring the signs did not know the dose of pirbuterol received by the horse and was unaware of the lung function data. Nasal, abdominal and total scores were significantly related to changes in lung function and changes in breathing pattern. There were significant differences between total scores greater than 5 in indices that reflected changes in breathing strategy (peak inspiratory and expiratory flow), peripheral airway obstruction (dynamic elastance), and effort of breathing (maximal change in pleural pressure). Below a total score of 5, there were fewer significant differences in lung function even though measurements of pulmonary resistance and dynamic elastance indicated considerable airway obstruction. Failure of clinical score to reflect this low-grade airway obstruction suggests that airway disease is underdiagnosed and its detection would be helped by the availability of a convenient lung function test.