Breath characteristics and adventitious lung sounds in healthy and asthmatic horses

BACKGROUND

Standard thoracic auscultation suffers from limitations, and no systematic analysis of breath sounds in asthmatic horses exists.

OBJECTIVES

First, characterize breath sounds in horses recorded using a novel digital auscultation device (DAD). Second, use DAD to compare breath variables and occurrence of adventitious sounds in healthy and asthmatic horses.

ANIMALS

Twelve healthy control horses (ctl), 12 horses with mild to moderate asthma (mEA), 10 horses with severe asthma (sEA) (5 in remission [sEA-], and 5 in exacerbation [sEA+]).

METHODS

Prospective multicenter case-control study. Horses were categorized based on the horse owner-assessed respiratory signs index. Each horse was digitally auscultated in 11 locations simultaneously for 1 hour. One-hundred breaths per recording were randomly selected, blindly categorized, and statistically analyzed.

RESULTS

Digital auscultation allowed breath sound characterization and scoring in horses. Wheezes, crackles, rattles, and breath intensity were significantly more frequent, higher (P < .001, P < .01, P = .01, P < .01, respectively) in sEA+ (68.6%, 66.1%, 17.7%, 97.9%, respectively), but not in sEA- (0%, 0.7%, 1.3%, 5.6%) or mEA (0%, 1.0%, 2.4%, 1.7%) horses, compared to ctl (0%, 0.6%, 1.8%, -9.4%, respectively). Regression analysis suggested breath duration and intensity as explanatory variables for groups, wheezes for tracheal mucus score, and breath intensity and wheezes for the 23-point weighted clinical score (WCS23).

CONCLUSIONS AND CLINICAL IMPORTANCE

The DAD permitted characterization and quantification of breath variables, which demonstrated increased adventitious sounds in sEA+. Analysis of a larger sample is needed to determine differences among ctl, mEA, and sEA- horses.

Bayesian evaluation of the accuracy of a thoracic auscultation scoring system in dairy calves with bronchopneumonia using a standard lung sound nomenclature

BACKGROUND

Although thoracic auscultation (AUSC) in calves is quick and easy to perform, the definition of lung sounds is highly variable and leads to poor to moderate accuracy in diagnosing bronchopneumonia (BP).

HYPOTHESIS/OBJECTIVES

Evaluate the diagnostic accuracy of an AUSC scoring system based on a standard lung sound nomenclature at different cut-off values, accounting for the absence of a gold standard test for BP diagnosis.

ANIMALS

Three hundred thirty-one calves.

METHODS

We considered the following pathological lung sounds: increased breath sounds (score 1), wheezes and crackles (score 2), increased bronchial sounds (score 3), and pleural friction rubs (score 4). Thoracic auscultation was categorized as AUSC1 (positive calves for scores ≥1), AUSC2 (positive calves for scores ≥2), and AUSC3 (positive calves for scores ≥3). The accuracy of AUSC categorizations was determined using 3 imperfect diagnostic tests with a Bayesian latent class model and sensitivity analysis (informative vs weakly informative vs noninformative priors and with vs without covariance between ultrasound and clinical scoring).

RESULTS

Based on the priors used, the sensitivity (95% Bayesian confidence interval [BCI]) of AUSC1 ranged from 0.89 (0.80-0.97) to 0.95 (0.86-0.99), with a specificity (95% BCI) of 0.54 (0.45-0.71) to 0.60 (0.47-0.94). Removing increased breath sounds from the categorizations resulted in increased specificity (ranging between 0.97 [0.93-0.99] and 0.98 [0.94-0.99] for AUSC3) at the cost of decreased sensitivity (0.66 [0.54-0.78] to 0.81 [0.65-0.97]).

CONCLUSIONS AND CLINICAL IMPORTANCE

A standardized definition of lung sounds improved AUSC accuracy for BP diagnosis in calves.

Association between computer-aided lung auscultation and treatment failure risk in calves treated for respiratory disease

The use of computer-aided lung auscultation (CALA, Whisper Veterinary Stethoscope; Merck Animal Health, Madison, New Jersey, USA) is a relatively new approach to assist in confirming the diagnosis of bovine respiratory disease (BRD). For this prospective cohort study at 1 feedlot in the United States, a CALA score was generated for 2726 feeder cattle (calf-fed Holsteins and mixed-breed beef animals) at the time of the first BRD diagnosis and treatment. All cattle were treated according to the same BRD protocol prescribed for that facility and the protocol was not influenced by the CALA score. Data were collected for 120 d after enrollment. In this study, the risk of BRD retreatment and the risk of BRD mortality were each significantly (P < 0.05) associated with the CALA score at the time of first BRD diagnosis and treatment, and those risks increased (numerically and in some cases statistically) as the CALA score increased.

Evaluation of equine cecal motility by ausculation, ultrasonography and electrointestinography after jejunocecostomy

OBJECTIVE

Horses often suffer reduced intestinal motility after jejunocecostomy. Therefore, accurate evaluation of intestinal motility is important for the prevention, diagnosis and treatment of this condition. The purpose of this study was to evaluate intestinal motility in horses after jejunocecostomy using three different methods, i.e. auscultation, ultrasonography and electrointestinography.

ANIMALS

Six healthy thoroughbreds were used in this study. They were subjected to jejunocecostomy.

PROCEDURE

Bowel sounds in the right paralumbar fossa were assigned a score of 0-3 for intestinal motility evaluation by auscultation, and the number of cecal contractions during a 3-min period were counted by ultrasonography. Electrointestinography (EIG) was used to measure percutaneous potential of the cecum.

RESULTS

We identified three specific postoperative periods: the period of reduced intestinal motility (postoperative day 1 to day 2), in which intestinal motility declined, the unstable period (day 3 to day 7), in which intestinal motility partially recovered, and the full recovery period (day 8 to day 31), in which intestinal motility returned to preoperative state. Careful management was found to be especially important during the period of reduced intestinal motility and the unstable period. We found that, in healthy horses that underwent jejunocecostomy, it takes approximately one month for the cecum to return to normal motility patterns observed before surgery.

CONCLUSION

We have shown in this study that evaluation of intestinal motility after jejunocecostomy in horses by EIG is more objective and provides more details than evaluation by auscultation or ultrasonography.

The effects of feeding and fasting on gastrointestinal sounds in adult horses

The effect of changes in feed intake on auscultatable gastrointestinal sounds has not been systematically studied. Disagreement also is present in the literature about variation in sounds according to the quadrant of auscultation. Gastrointestinal sounds were recorded over the center of the left dorsal, left ventral, right ventral, and right dorsal quadrants and over the middle of the right abdominal flank. During 24 hours (n = 4) or 48 hours (n = 5) of fasting, there was a reduction in the intensity of gastrointestinal sounds as assessed by analysis of sound recordings. There was also a reduction in the number of mixing-like and propulsive-like sounds heard by 2 blinded observers. After refeeding, there was a marked increase in sound. Sound intensity varied among abdominal quadrants, but blinded observers did not notice significant differences in the number of mixing-like sounds. The left dorsal quadrant was quieter than others during fasting and refeeding. The right ventral quadrant appeared to be least affected by fasting, and sounds were louder over the right ventral and right middle quadrants than over the others. The blinded observers' perceptions of sound correlated poorly with one another and with objective measures of sound intensity. This experiment demonstrates the effectiveness of computerized analysis of abdominal sound in detecting a reduction in the intensity of gastrointestinal sounds during fasting and their return during refeeding. The left dorsal quadrant was quieter than other quadrants, likely because of its position over the small colon. There was considerable observer variation in the number of intestinal sounds heard.

Low intensity heart murmurs in boxer dogs: inter-observer variation and effects of stress testing

Inter-observer variation in the detection and grading of low intensity heart murmurs in boxer dogs was investigated. Six veterinarians with different levels of experience examined 27 boxers by cardiac auscultation. The dogs were auscultated before and after exercise, and the results were compared with phonocardiographic and echocardiographic examinations performed at rest and during two different stress tests. A subvalvular aortic ridge was identified in six dogs on two-dimensional echocardiography. Using dogs with low intensity murmurs or dogs free of heart murmurs, inter-observer agreement was positively correlated to the level of experience at rest (weighted kappa [kappa] 0.14 to 0.75), while the agreement was poor after exercise (weighted kappa 0.01 to 0.36). The presence of a subvalvular aortic ridge was associated with higher aortic flow velocities (P<0.002) and higher auscultatory murmur grading (P<0.001). There was an increase in murmur duration during one kind of stress test (P<0.001) and in aortic flow velocity during the other (P=0.001).

Results of intradermal tests in horses without atopy and horses with atopic dermatitis or recurrent urticaria

OBJECTIVE

To compare results of intradermal tests (IDT) for environmental allergens at 30 minutes and 4, 6, and 24 hours after injection in horses without atopy and horses with atopic dermatitis (AD) or recurrent urticaria (RU).

ANIMALS

22 horses without atopy, 10 horses with RU, and 7 horses with AD.

PROCEDURE

In all horses, medical history was obtained, and results of physical examination, hematologic examination, serum biochemical analyses, examination of bronchoalveolar lavage fluid, and IDT with 73 allergens were examined.

RESULTS

Horses with AD or RU had a significantly greater mean number of positive reactions for IDT, compared with horses without atopy. Horses with AD had a significantly greater number of positive reactions than horses without atopy in every allergen group at all time periods, except for molds at 4 and 24 hours. Horses with RU had a significantly greater number of positive reactions than horses without atopy in every allergen group, except for molds at 30 minutes and 4 and 6 hours, trees at 4 and 6 hours, and grasses at 4 hours.

CONCLUSIONS AND CLINICAL RELEVANCE

A significantly greater number of positive reactions for IDT in horses with AD or RU, compared with horses without atopy, provides evidence of type-I IgE-mediated hypersensitivity for these diseases. Evaluation of results of IDT performed in horses with AD or RU is useful in determining specific allergens for the formulation of immunotherapy along with providing identification of allergens that could be useful when creating avoidance strategies.

Physical examination of the pulmonary system

Physical examination of the pulmonary system includes inspection, auscultation, percussion, and palpation. By integrating these findings, it is often possible to diagnose and differentiate pulmonary edema, pleural effusion, pneumothorax, pulmonary fibrosis, and tracheal collapse. The veterinarian can use the physical examination optimally by initially performing examinations with those who are experienced with the methods and with an understanding of the relatively simple laws of physiology and physics governing transmission of sounds from the patient's lung.

[Importance of differential diagnosis of ringing and splashing sounds in the abdomen of adult cattle]

In cattle liquid and gas in the abdominal cavity can be detected from the outside by use of simultaneous auscultation and percussion or by auscultation with simultaneous shaking of the abdominal wall. Size, area and the quality of the "ping" and splashing sounds are helpful to determine which organs are involved in the disease. Nine possible reasons for intraabdominal gas- and liquid accumulation are discussed. In 12 schematic figures the areas of externally detectable "ping" and splashing sounds are compared with the topographic anatomical situation inside the abdomen.

Assessment of the ruminant respiratory system

With practice, complete use of the methods of this assessment: history, detailed examination of the head and neck, cough induction, chest auscultation and percussion, and chest auscultation following forced rebreathing can be completed within 10 minutes. The examination can provide a great deal of new information regarding the respiratory system that would go undetected on a more general physical examination. In cases in which the diagnosis is still in question or requires confirmation, this will also enable the optimal use of appropriate ancillary tests, as described in the article on ancillary testing for the respiratory tract elsewhere in this issue.

An investigation of the incidence of chronic obstructive pulmonary disease (COPD) in random populations of Swiss horses

The incidence of Chronic Obstructive Pulmonary Disease (COPD) in Switzerland was determined in three groups of horses selected at random. Group A (97 horses) and Group B (93 horses) had no history of respiratory disease, but Group C (113 horses) had a history of lower respiratory tract disease. All horses were examined by auscultation of the respiratory tract under forced breathing, endoscopic examination of the upper and lower respiratory tract, arterial blood gas analysis at rest and cytological examination of respiratory secretions (RS). Fifty-four per cent of the horses in Group A and 54.8 per cent of Group B were diagnosed as suffering clinical COPD and only 12.4 per cent of horses in Group A and 8.6 per cent in Group B had no detectable abnormalities in their lower respiratory tracts. In Group B, 19.4 per cent were considered to be suffering from parasitic pulmonary disease indicated by elevated numbers of eosinophils in their RS. Pharyngeal lymphoid hyperplasia was exhibited in 70.1 per cent of Group A and 74.2 per cent of Group B. Cytological examination of RS was useful to determine if the secretions found in the trachea originated from the upper or lower respiratory tract. Arterial blood gas analysis revealed no significant differences between healthy horses and those with subclinical or mild COPD.

Echocardiographic detection of an intact aneurysm in a horse

Two-dimensional real-time echocardiographic examination of a 3-year-old Thoroughbred gelding with pleuropneumonia revealed an intact aneurysm of the right sinus of Valsalva, which was confirmed at postmortem examination. The horse had no clinical signs associated with the aneurysm.

Observer variation in equine abdominal auscultation

The reliability of abdominal auscultation was investigated via an observer variation study. Clinicians listened to a variety of minute-long equine gut sound recordings. They evaluated the amount of gut sounds as 'absent', 'decreased', 'normal', or 'increased'. They subsequently evaluated the same recordings replayed in a different order. Intra- and inter-observer agreement was measured by the statistic kappa. There was significant intra-observer (kappa 0.57) agreement, but less agreement between observers (kappa 0.37). The best agreement was on the classification of sound tracks as 'absent' (intra-observer kappa 0.72 and inter-observer kappa 0.55). There was significant correlation between the clinicians' average assessment of the recordings and their acoustic energy levels. In this study abdominal noise was reliably assessed by auscultation. Standardised techniques and definitions would probably enhance the reliability of abdominal auscultation for the evaluation of gastrointestinal disease.

Abdominal auscultation in the detection of experimentally induced gastrointestinal sand accumulation

A blind study was designed to determine if abdominal auscultation is an effective method for detecting the presence of intestinal sand. Fifteen horses divided into two groups were used in the study. There were seven horses in Group 1 and eight horses in Group 2. All horses were auscultated and determined to be free of sand sounds before initiation of Trial 1. Group 1 horses were given 4.2 g/kg body weight of sand via nasogastric tube using carboxymethylcellulose (CMC) as a suspending agent at 9.0 ml/kg body weight. Group 2 horses were given CMC only. Horses remained in the same group through all trials. A total of five trails, each lasting 24 hours, was performed. Dosing with sand and CMC or CMC alone was repeated at the beginning of each trial. Abdominal auscultation was performed on each of the 15 horses beginning on Trial 2 by an investigator with no knowledge of the grouping of the horses. The ventral abdomen was auscultated for 5 minutes at 7 hours and 17 hours after trial initiation. When a horse was considered positive for intestinal sand by auscultation, the horse was eliminated from future trials. On Trial 2, no horses were positive; on Trial 3, one horse; on Trial 4, two horses, and on Trial 5, four horses. Sounds considered characteristic for sand in the intestinal tract were eventually identified in all Group 1 horses. No horses in Group 2 were ever identified as having sounds characteristic for intestinal sand at any point during this investigation.

Correlation of a disease scoring system with arterial PO2 values in respiratory syncytial virus infection in calves

The mean arterial PO2 value measured in blood obtained by puncture of the brachial artery of 20 calves with acute clinical signs of a bovine respiratory syncytial virus (BRSV) infection was 8.4 +/- 1.9 kPa. The values differed significantly from arterial PO2 values of eleven healthy calves (mean 14.2 +/- 1.5 kPa). A disease scoring system is presented based on the type of respiration and the findings on auscultation. A high correlation (r = -0.87) was found between disease scores and arterial PO2 values. This indicates that the described disease scoring system can be a useful tool in the evaluation of the severity and course of BRSV infections in calves, and could be used for evaluating the efficacy of BRSV vaccines in the field. The course of disease was studied in 127 calves with clinical signs of serologically proven BRSV infection. Animals with mild respiratory signs during the acute phase of disease remained free of severe respiratory problems until the end of a 35-day examination period. Mean disease scores indicated that animals with severe signs in the acute phase often developed persistent respiratory problems.

The identification of structures and conditions responsible for right side tympanitic resonance (ping) in adult cattle

In review of the case records of all cattle greater than or equal to 2 years of age admitted to the Large Animal Hospital of the New York State College of Veterinary Medicine in a 3-year-period, 366 were identified as having areas of right side tympanitic resonance (ping) due to gas distention of intra-abdominal structures. The source of the ping was identified as abomasum in 137 cattle, various segments of the intestinal tract in 157 cattle, and peritoneal gas in 2 cattle. In 70 cattle, no identification was made as to the source of the ping. In 151 (41%) of the cattle with areas of ping, both the clinical and definitive (surgical or necropsy) identification of the source of the ping was recorded. In these cattle, the sensitivity and predictive value of the clinical identification were determined for each structure. The sensitivity and predictively; for cecum and/or ascending colon, the sensitivity and predictive value were both 87%. Of all cattle in which a right side ping was recorded, the principal final diagnoses were: left displacement of the abomasum (116), right displacement of the abomasum (77), abomasal (and omasal) and volvulus (60), other gastrointestinal conditions (73), nongastrointestinal conditions(40).

Studies on the physiopathology of chronic obstructive pulmonary disease in horses. I. Clinical signs

Twenty cases of chronic cough originating in the lung and associated with loss of performance were clinically examined. The physical signs observed were compared with those observed in a control series of 38 clinically normal horses. Reduced work tolerance, coughing for more than 3 months and abnormal pulmonary sounds (râles) were primary signs of chronic obstructive pulmonary disease (COPD). Forced abdominal expiratory efforts and pumping of the anus were regarded as confirmatory signs. Neither nasal discharge nor increased marginal distance was found to be a reliable sign of COPD. The mean respiratory frequency of the COPD subjects, namely 25,4 per minute, was significantly higher than the 16,7 per minute (P less than 0,001) of the 38 normal subjects.

Respiratory sounds recorded by radio-stethoscope from normal horses at exercise

A graphic representation is presented of respiratory sounds recorded by a radio-stethoscope from normal horses exercised at the walk, trot, canter and gallop. Methods whereby inspiratory and expiratory sounds were distinguished are discussed. The form of amplitude envelopes of the sounds recorded at different gaits are compared. Certain measurements of relative amplitudes and the form of amplitude envelopes of the recorded respiratory sounds can be recognised as typical of normal horses when exercised at the canter and gallop. The influence of some physiological events (e.g. deglutition on the rhythm of normal respiration at the canter and gallop) is indicated.

The development of a radio-stethoscope for use in the horse at rest and during exercise

The development of a radio-stethoscope for horses is described. The equipment consisted of a sound transducer applied to the skin adjacent to the trachea and a radio transmitter attached to the saddle. The signals emitted were detected by telemetry and recorded on a magnetic tape-recorder. The recorder incorporated a monitor earphone so that sounds could be reproduced at the time of recording. The frequency response obtainable ranged from a few Hz to 4 KHz. This technique provided an objective means of studying the respiratory sounds generated during exercise although absolute values could not be measured.

Persistent cecal dilatation in a lactating dairy cow

Cecal dilatation in cattle is usually manifested by a syndrome of intestinal obstruction requiring surgical intervention. A patient is presented persistent dilatation of the cecum for ten months without evidence of impaired appetite or milk production. The initial clinical signs, progress of the case, and laboratory data are described.

Left displacement of the abomasum in a clinically normal cow

A cow with left displacement of the abomasum (lda) was found to be clinically normal for 1 1/2 years. During this period, the cow calved twice and ate and produced milk normally. Auscultation and percussion at approximately weekly intervals revealed the continuing abomasal displacement, which was confirmed at necropsy.

The indirect measurement of arterial blood pressure in the horse

An accurate modified auscultatory technique for the indirect measurement of arterial pressure in the horse is described. Limitations of the method were sensitivity to external motion in nervous, conscious horses, and the failure to detect Korotkoff sounds in shocked, anaesthetized surgical cases. The apparatus required for the method is expensive and is probably impractical for routine monitoring during anaesthesia.