Clinicopathological and radiographic indicators for orogastric decompression in rabbits presenting with intestinal obstruction at a referral hospital (2015-2018).

BACKGROUND: Orogastric decompression is regularly recommended as a part of both medical and pre-surgical treatment for small intestinal obstruction in rabbits. However, guidelines as to when orogastric decompression is indicated are sparse. METHODS: The medical records of 35 rabbits diagnosed with gastrointestinal obstruction over a 3-year period were examined. Differences in presentation, clinicopathological and radiographic examination findings, treatments and outcome were evaluated. RESULTS: Approximately 49% of the cases evaluated were considered to have non-life-threatening disease, while 51% were considered to have life-threatening disease. The severity of gastric obstruction was correlated with the severity of hyperglycaemia (average 25.7 mmol/L; 463 mg/dl) and corresponding hyponatraemia (Na < 138 mmol/L; 138 mEq/L). These patients were treated with orogastric decompression and medical management only. LIMITATIONS: This is a retrospective study and there are inherent limitations involving the quality of the data and data collection. Additional studies should be completed that strive for larger sample sizes to compare the differences in outcome between surgical and medical management, as well as investigate the outcomes of rabbits with hyperglycaemia and hyponatraemia that did not have an orogastric decompression performed. CONCLUSIONS: Blood glucose and sodium concentrations, in combination with radiographic findings, may aid clinicians in determining if orogastric decompression is indicated to stabilise rabbits with small intestinal obstructive disorders.

Ultrasound-guided tenoscopic decompression of digital sheath synoviocoeles in 10 horses.

OBJECTIVE: To report the diagnostic features and clinical outcome of horses with digital flexor tendon sheath (DFTS) synoviocoeles treated tenoscopically under ultrasonographic guidance. STUDY DESIGN: Retrospective case series. ANIMALS: Client-owned horses (n = 10). METHODS: Medical records were searched for horses with lameness localized to the region of the DFTS and clinical evidence of a fluid-filled mass (synoviocoele) associated with the DFTS. Diagnostic imaging and surgical findings, together with long-term outcome, were reported. RESULTS: Lameness and synoviocoeles were unilateral (5 forelimbs, 5 hindlimbs; 3 lateral and 2 medial in both) and located proximal to the palmar/plantar annular ligament. Synoviocoeles had a firm consistency and focal pain with inability to deflate on non-weight-bearing examination. Intrathecal DFTS anesthesia was positive in 7/8 horses in which it was performed, with the remainder localized to the region of the synoviocoele using perineural and/or intralesional anesthesia. Communication between the DFTS and synoviocoele was suspected ultrasonographically in all cases and confirmed on contrast tenography (6/6). Tenoscopic fenestration of the communication between the DFTS and synoviocoele under ultrasonographic guidance, with treatment of concurrent intrathecal injury (4/10), resolved the lameness in all horses re-evaluated by a veterinarian (9/9) and allowed return to full athletic function in all cases at long-term follow up (median 5 years; range 1.25-9 years). CONCLUSION: Tenoscopic decompression was an effective treatment for DFTS synoviocoeles, which, along with treatment of concurrent intrathecal injury, carried an excellent prognosis and avoided the need for resection via an extrasynovial approach.

Left atrial decompression as a palliative minimally invasive treatment for congestive heart failure caused by myxomatous mitral valve disease in dogs: 17 cases (2018-2019).

OBJECTIVE: To determine whether left atrial decompression (LAD) would reduce left atrial pressure (LAP) in dogs with advanced myxomatous mitral valve disease (MMVD) and left-sided congestive heart failure (CHF) and to describe the LAD procedure and hemodynamic alterations and complications. ANIMALS: 17 dogs with advanced MMVD and left-sided CHF that underwent LAD. PROCEDURES: The medical record database was retrospectively reviewed for all LAD procedures attempted in dogs with MMVD and left-sided CHF between October 2018 and June 2019. Data were collected regarding signalment (age, breed, weight, and sex), clinical signs, treatment, physical examination findings, and diagnostic testing before and after LAD. Procedural data were also collected including approach, technique, hemodynamic data, complications, and outcome. RESULTS: 18 LAD procedures performed in 17 patients were identified. Dogs ranged in age from 7.5 to 16 years old (median, 11 years) and ranged in body weight from 2.9 to 11.6 kg (6.4 to 25.5 lb) with a median body weight of 7.0 kg (15.4 lb). Minimally invasive creation of an atrial septal defect for the purpose of LAD was successful in all dogs without any intraoperative deaths. Before LAD, mean LAP was elevated and ranged from 8 to 32 mm Hg with a median value of 14 mm Hg (reference value, < 10 mm Hg). Following LAD, there was a significant decrease in mean LAP (median decrease of 6 mm Hg [range, 1 to 15 mm Hg]). Survival time following LAD ranged from 0 to 478 days (median, 195 days). CONCLUSIONS AND CLINICAL RELEVANCE: For dogs with advanced MMVD and left-sided CHF, LAD resulted in an immediate and substantial reduction in LAP.

Pathological consequences of low atmospheric pressure stunning in broiler chickens.

Low atmospheric pressure stunning (LAPS) is a novel approach to pre-slaughter stunning of chickens using progressive hypobaric hypoxia by the application of gradual decompression (280s cycle) according to a set of prescribed pressure curves. Low atmospheric pressure stunning produces a non-recovery state. Concerns have been raised relating to the possible pathological and welfare consequences of expansion of air in the body during LAPS. In a randomised trial, we compared the gross pathology of broilers exposed to LAPS with a control group euthanised by intravenous injection of pentobarbital sodium (60 mixed sex broilers per treatment). The birds were exposed to each treatment in triplets and all birds were subject to necropsy examination to detect and score (1 to 5, minimal to severe) haemorrhagic lesions or congestion for all major organs and cavities (e.g. air sacs, joints, ears and heart) as well as external assessment for product quality (e.g. wing tips). Behavioural data (latency to loss of posture and motionless) and chamber cycle data (temperature, humidity, pressure and oxygen availability) confirmed that LAPS had been applied in a manner representative of the commercial process. All of the organs observed were structurally intact for both treatment groups. No lesions were observed in the external ears, oral cavity, tracheal lumen, crop and air sacs of birds from either treatment group. There was no difference between treatments in the wingtips, nasal turbinates, thymus, biceps femoralis and colon. Haemorrhagic lesions were observed in the calvaria, brains, hearts and lungs of both treatment groups, but lesions in these areas were more severe in the LAPS treatment group. It was not possible to distinguish between pathological changes induced by decompression or recompression. In the barbiturate group, more severe haemorrhagic lesions were observed in the superficial pectoral muscles as well as greater congestion of the infraorbital sinuses, liver, spleens, duodenum, kidneys and gonads. These findings provide evidence that LAPS did not result in distension of the intestines and air sacs sufficient to cause changes, which were grossly visible on postmortem examination. There was also no evidence of barotrauma in the ears and sinuses. The pathological changes observed in the barbiturate treatment were as expected based on barbiturate toxicity. Low atmospheric pressure stunning appears to produce pathological changes by a variety of well-established mechanisms, and while these pathological data have limited value as welfare indicators, the results confirm that organ integrity was not compromised by the process.

A piecewise regression approach for determining biologically relevant hydraulic thresholds for the protection of fishes at river infrastructure.

A piecewise regression approach was used to objectively quantify barotrauma injury thresholds in two physoclistous species, Murray cod Maccullochella peelii and silver perch Bidyanus bidyanus, following simulated infrastructure passage in a barometric chamber. The probability of injuries such as swimbladder rupture, exophthalmia and haemorrhage, and emphysema in various organs increased as the ratio between the lowest exposure pressure and the acclimation pressure (ratio of pressure change, R(NE:A) ) reduced. The relationship was typically non-linear and piecewise regression was able to quantify thresholds in R(NE:A) that once exceeded resulted in a substantial increase in barotrauma injury. Thresholds differed among injury types and between species but by applying a multispecies precautionary principle, the maintenance of exposure pressures at river infrastructure above 70% of acclimation pressure (R(NE:A) of 0·7) should protect downstream migrating juveniles of these two physoclistous species sufficiently. These findings have important implications for determining the risk posed by current infrastructures and informing the design and operation of new ones.

Examination of the equine patient with gastrointestinal emergency.

Clinical examination of the equine patient with acute abdominal pain should identify the affected body system and yield a provisional diagnosis. Determination of signalment, history, physical examination, and basic laboratory tests should assist in classification of the gastrointestinal disorder and direct the therapeutic plan. Determination of the definitive diagnosis of abdominal pain based on clinical examination is not crucial. For a successful outcome, efforts should be directed toward early recognition of the need for surgery and treatment of cardiovascular compromise in horses with severe gastrointestinal disease.

Remote monitoring of neuraxial function in anesthetized dogs in compression chambers.

This paper describes the development of an electrophysiological model using spinal and cortical evoked potentials (SEP, CEP), for the diagnosis and monitoring of spinal cord decompression sickness (DCS) in anesthetized dogs. A comparison of alpha-chloralose with sodium pentobarbital showed that the latter caused a reduction in CEP amplitude. Continuous observation of EPs over 5 h showed a small reduction and an increasing variance of amplitude with time. The effectiveness of the method in the diagnosis of DCS and in studies of the adequacy of treatment is illustrated with several examples.

Hemodynamics during experimental gastric dilatation-volvulus in dogs.

Gastric dilatation-volvulus (at 30 mm of Hg of gastric pressure) was experimentally induced in 8 dogs under sodium pentobarbital anesthesia. Hemodynamic indices including cardiac output, mean aortic pressure, left ventricular end diastolic pressure, heart rate, total peripheral resistance, and dp/dtmax were measured during a 180-minute period of gastric dilatation-volvulus and for 120 minutes after gastric decompression. Experimental gastric dilatation-volvulus resulted in significant (P less than 0.05) decreases in cardiac output (64%), mean aortic pressure (48%), left ventricular end diastolic pressure (68%), and ventricular dp/dtmax (32%) compared to 4 control dogs. Hemodynamic indices returned toward control values after gastric decompression. It was concluded that gastric dilatation-volvulus in the present experiment was capable of inducing hemodynamic alterations of a magnitude similar to those reported in gastric dilatation studies, using higher gastric pressures.

Isovolumetric indices and humoral cardioactive substance bioassay during clinical and experimentally induced gastric dilatation-volvulus in dogs.

Plasma collected from 6 experimentally induced and 29 clinical cases of gastric dilatation-volvulus was assayed for cardioactive substances utilizing isolated canine papillary muscles. The results were correlated with in vivo isovolumetric indices of myocardial contractility observed during experimental gastric dilatation-volvulus in the dog. Cardioactive substances were not detected during experimental gastric dilatation-volvulus. Two experimental dogs showed a cardiostimulatory response and 4 experimental dogs showed a cardiodepressant response following gastric decompression. Cardioactive substance bioassays correlated well with isovolumetric indices in experimental dogs. The variable response in cardioactive substance bioassay observed in experimental dogs was consistent with clinical gastric dilatation-volvulus bioassays which produced a widely variable response ranging from strongly cardiostimulatory to strongly cardiodepressant.

Creatine phosphokinase activities in rainbow trout, Salmo gairdneri, associated with rapid decompression.

Serum creatine phosphokinase (CPK) activity levels were monitored in rainbow trout following rapid decompression. Serum activity was elevated 8.5-fold at 24 h and 15-fold at 48 h after decompression from 100-feet sea water (fsw) dives of 1 1/2 h duration. Serum enzyme activity was unchanged in the 66-fsw group. Stress results indicated a proportional relationship exists between serum CPK activity and muscular activity. CPK activities were found to be 1,023 in skeletal (white) muscle and 255 mumol . min-1 . g-1 in heart ventricle. Elevated CPK activity was not associated with tissue necrosis and is considered a consequence of increased anaerobic respiration stimulated by muscular activity and pressure-induced peripheral hypoxia.