[Influence of atracurium on cardiovascular parameters in horses undergoing vitrectomy during general anaesthesia, and on recovery duration and quality]. / Einsatz von Atracurium bei der Vitrektomie des Pferdes. Einfluss auf Operationsbedingungen, Allgemeinanästhesie und Aufstehphase.

OBJECTIVE: In most ocular procedures, a central position of the eye is necessary. This can be achieved using a deep plane of anaesthesia, locoregional blocks or with neuromuscular blocking agents. The aim of this study was to evaluate the influence of atracurium on cardiovascular parameters, and on recovery quality and duration in horses. MATERIAL AND METHODS: Thirty-four warmblood horses undergoing in total 50 vitrectomies were divided into two groups. Premedication, induction and maintenance were identical in all patients. After 20 minutes, horses of group A received atracurium (0.1 mg/kg) while in the control group (group K) the depth of anaesthesia was adapted to keep the bulbus in a central position. Dobutamine and fluids were administered to maintain the mean arterial blood pressure (MAP) above 70 mmHg. Cardiac output (CO), heart rate (HR), MAP, respiratory rate, end-expiratory isoflurane concentration (ETIso) and dobutamine requirements were determined. Position and movement of the globe during the surgical procedure were scored. Time and quality of the recovery period was scored. RESULTS: Horses of group K required significantly higher concentrations of isoflurane (group A: 1.08 ± 0.1%; group K: 1.34 ± 0.2%) and had an overall lower MAP (group A: 88.4 ± 10.3 mmHg; group K: 76.6 ± 11.6 mmHg) and CO (group A: 36.9 ± 11.7 l/min; group K: 28.5 ± 7.2 l/min) but needed significantly more dobutamine (group A: 0.37 ± 0.17 µg/kg/min; group K: 0.99 ± 0.46 µg/kg/min) compared to group A. Complete relaxation occurred 9.5 ± 2.5 minutes after atracurium bolus and lasted for 25 ± 7.1 minutes. The score of the bulbus position and movement was significantly lower in group A, resulting in a better quality for the surgical procedure. In group A, the recovery time to standing was significantly shorter (group A: 18.1 ± 5.4 min; group K: 31.5 ± 7.1 min), with no difference in quality. CONCLUSION AND CLINICAL RELEVANCE: The use of atracurium resulted in a better cardiovascular condition, probably because of the isoflurane-sparing effect. The recovery time was shorter in these horses without negative effects on recovery quality. No signs of residual atracurium effects were detected.

Influence of modified open lung concept ventilation on the cardiovascular and pulmonary function of horses during total intravenous anaesthesia.

The influence of a modified open lung concept (mOLC) on pulmonary and cardiovascular function during total intravenous anaesthesia (TIVA) in horses was evaluated. Forty-two warmblood horses (American Society of Anesthesiologists class 1 to 2), scheduled for elective surgery (mean [sd] weight 526 [65] kg, age 6.4 [5.4] years) were randomly divided into three groups: ventilation with mOLC, intermittent positive-pressure ventilation (IPPV), and spontaneous breathing. Premedication (0.8 mg/kg xylazine), induction (2.2 mg/kg ketamine and 0.05 mg/kg diazepam) and maintenance of anaesthesia with TIVA (1.4 mg/kg/hour xylazine, 5.6 mg/kg/hour ketamine and 131.1 mg/kg/hour guaifenesin), with inhalation of 35 per cent oxygen in air, were identical in all horses. Heart rate, respiratory rate, mean arterial blood pressure (MAP), pH, and arterial partial pressure of oxygen (p(a)O(2)) and carbon dioxide (p(a)CO(2)) were evaluated. Data were collected every 10 minutes from 20 to 90 minutes anaesthesia time. Factorial analysis of variance and Tukey's post hoc test were used for statistical analysis (a=5 per cent). Horses in the mOLC-ventilated group had an overall significantly higher p(a)O(2) (16.9 [1.0] v 11.7 [1.34] v 10.5 [0.57] kPa) and lower MAP (93.1 [5.47] v 107.1 [6.99] v 101.2 [5.45] mmHg) than the IPPV and spontaneously breathing groups, respectively.

Whole-genome scan for guttural pouch tympany in Arabian and German warmblood horses.

Equine guttural pouch tympany (GPT) is a hereditary disease in foals of several breeds, including thoroughbreds, Arabian, Quarter and warmblood horses. We performed a whole-genome scan for GPT in 143 horses from five Arabian and five German warmblood families and genotyped 257 microsatellites. Chromosome-wide significant linkage was detected on ECA2 and ECA15 using multipoint non-parametric linkage analyses. Analyses stratified by sex revealed chromosome-wide significant linkage on ECA2 for fillies and chromosome-wide significant linkage on ECA15 for colts. For Arabian colts, the quantitative trait locus (QTL) on ECA15 was genome-wide significant. Haplotypes including two to four microsatellites within the QTL on ECA2 and 15 in fillies and colts, respectively, were significantly associated with GPT for both breeds. Thus, our analysis indicated sex-specific QTL, a fact which is in agreement with a two- to fourfold higher incidence of GPT in females. This is the first report of QTL for equine GPT and a first step towards identifying genes responsible for GPT.

Necrosis of the nasal conchae in 12 horses.

Twelve horses with a history of a unilateral malodorous nasal discharge were examined clinically, endoscopically and radiographically. The head of one of the horses was examined by computed tomography. Tissue samples were taken for microbiology from four of the horses and for histology from three. The conchal necrosis was unilateral in 11 of the horses and bilateral in the other, and no particular concha was affected more than the others. The affected tissue was removed transendoscopically with a polypectomy snare while the horses were sedated and standing. Mild disinfectants were used locally in six of the horses. After the removal of all the necrotic tissue, the affected concha healed without any complications in all 12 horses.

Reactivity of equine airways--a study on precision-cut lung slices.

A study was performed to evaluate the use of precision-cut lung slices (PCLS) for studies on the contraction of equine airways. Lungs of 10 horses were taken to prepare PCLS of approximately 250 microm from equine lung tissue using a special microtome. The lung slices were cultured and the enclosed small airways were monitored using a microscope with coupled digital camera, which was used to determine the airway luminal area and diameter from digital images. As indicated by the beating of the ciliated epithelium and reactivity of airways on methacholine challenge, the tissue slices were found to be viable for at least 24 h. The airways were not precontracted, as indicated by a missing dilatory effect of 1 mmol/L clenbuterol. Bronchoconstriction induced by both methacholine and histamine was found to be dose dependent. EC(50) values based on luminal area were 1.12 micromol/L x / / 3.82 for methacholine and 0.68 micromol/L x / / 6.99 for histamine. In conclusion, the PCLS technique is promising for studies on small airways in the equine lung. In the present study the basic principles of in vitro (ex vivo) examinations with equine PCLS on airway reactivity were developed.

Effects of two different dosages of dobutamine on pulmonary artery wedge pressure, systemic arterial blood pressure and heart rate in anaesthetized horses.

The purpose of the present study was to investigate the effects of two different dobutamine concentrations on pulmonary artery wedge pressure (PAWP) and on mean systemic arterial blood pressure (MAP) in horses anaesthetized with isoflurane, after induction of general anaesthesia with xylazine, ketamine and diazepam. Eight healthy warm-blood horses were included in the study. Each horse was subjected to general anaesthesia twice with two different dosages of dobutamine, 3 and 5 microg/kg bw/min, being infused over 15 min, starting 50 min after induction of general anaesthesia (T(0)). The heart rate, the PAWP and the MAP were recorded after 10 min (T(1)) and then every 5 min until 15 min after cessation of intravenous dobutamine administration (T(3)-T(5)). The PAWP was measured by a right heart catheter, which was positioned in the pulmonary capillaries. Mean systemic arterial blood pressure was monitored at the facial artery for the duration of general anaesthesia. All parameters increased at both dosage rates of dobutamine and decreased significantly when dobutamine administration ceased. The increase in heart rate was significantly higher after administration of 3 microg/kg bw/min dobutamine compared with the dosage of 5 microg/kg bw/min dobutamine. The increase in MAP was also higher at this dosage, but not significantly different to the dosage of 5 microg/kg bw/min dobutamine. During both dosages the MAP was above a value considered to be compatible with good peripheral circulation. The greater increase in PAWP was observed during administration of 5 g/kg bw/min dobutamine, but PAWP was not significantly different with the dosage of 3 microg/kg bw/min dobutamine. In conclusion, the administration of dobutamine led to an increase in MAP and PAWP above a value considered to be compatible with a good peripheral circulation. The results of the present study indicate that dobutamine improves circulation, in addition to its well-known effect on the periphery.

An unusual mucinous osteoma with features of an ossifying fibroma in the nasal cavity of a horse.

A 4-month-old Warm-blooded colt presented with facial distorsion and an abnormal respiratory noise of 2 weeks' duration. A proliferative mass was found endoscopically and by computer tomography. Clinical differential diagnosis included cyst formation of the concha, malformation and neoplasia. Euthanasia was followed by post-mortem examination, which revealed a well-circumscribed, semi-solid, jelly like structure, measuring 14.5 x 9.0 x 12.0 cm, in the left posterior nasal cavity extending into the left frontal and maxillary sinus. Histologically, the mass consisted of trabeculae of woven bone, focal lamellar bone and fibroblast proliferation within a moderate fibro-vascular stroma. Abundant mucin production was noted within areas of fibroblastic differentiation. Some areas contained irregularly shaped spicules of osteoid rimmed by osteoblasts, randomly distributed within a moderately vascularized, fibro-osseous stroma. On the basis of the histopathological features, a nasal mucinous osteoma with focal ossifying fibroma-like structures was diagnosed.

[On the way to isotopic spatial resolution: technical principles and applications of 16-slice CT]. / Auf dem Weg zur isotropen räumlichen Auflösung: Technische Grundlagen und Anwendungen der 16-Schicht-CT.

The broad introduction of multi-slice CT by all major vendors in 1998 was a milestone with regard to extended volume coverage, improved axial resolution and better utilization of the tube output. New clinical applications such as CT-examinations of the heart and the coronary arteries became possible. Despite all promising advances, some limitations remain for 4-slice CT systems. They come close to isotropic resolution, but do not fully reach it in routine clinical applications. Cardiac CT-examinations require careful patient selection. The new generation of multi-slice CT-systems offer simultaneous acquisition of up to 16 sub-millimeter slices and improved temporal resolution for cardiac examinations by means of reduced gantry rotation time (0.4 s). In this overview article we present the basic technical principles and potential applications of 16-slice technology for the example of a 16-slice CT-system (SOMATOM Sensation 16, Siemens AG, Forchheim). We discuss detector design and dose efficiency as well as spiral scan- and reconstruction techniques. At comparable slice thickness, 16-slice CT-systems have a better dose efficiency than 4-slice CT-systems. The cone-beam geometry of the measurement rays requires new reconstruction approaches, an example is the adaptive multiple plane reconstruction, AMPR. First clinical experience indicates that sub-millimeter slice width in combination with reduced gantry rotation-time improves the clinical stability of cardiac examinations and expands the spectrum of patients accessible to cardiac CT. 16-slice CT-systems have the potential to cover even large scan ranges with sub-millimeter slices at considerably reduced examination times, thus approaching the goal of routine isotropic imaging.

[Verrucous pastern dermatitis syndrome in heavy draught horses. Part II: Clinical findings]. / Zur Entstehung von Warzenmauke bei Kaltblutpferden. Teil II: Klinische Untersuchungen.

In the present field study the skin of the feet of 37 heavy draught horses of different breeds showing verrucous pastern dermatitis was examined clinically. Included were the degree of severity of the disease and the prevalence of anatomically normal structures associated with the skin: fetlock tufts of hair ("feathering"), ergots, chestnuts, bulges in the pastern region, cannon circumference. Each horse was examined for Chorioptes sp. skin mites. Information was also collected on the development of the skin alterations and housing conditions and feeding. These individual data were correlated with the clinical degree of severity of verrucous pastern dermatitis, which was evaluated using a numerical code (scoring system). In addition, punch biopsies were taken from the diseased skin of the feet and from healthy skin of the neck for comparative patho-histological examination (see Part III). Verrucous pastern dermatitis is a chronic disease which can be divided into four groups: scaling (group I), hyperkeratotic and hyperplastic plaque-like lesions (group II), tuberous skin masses (group III), and verrucous skin lesions with rugged surfaces (group IV). No correlation was found between the clinical degree of severity of the skin lesions and sex, breed, amount of work, use of stallions for breeding, grooming condition of the hair, white markings in the foot region, or Chorioptes sp. infestation. In regard to feeding it was found that the amount of maize and oats fed had some influence on the clinical degree of severity. Statistical analysis revealed a significant correlation between the clinical degree of severity and the age, the grooming condition of the hooves, and the mean cannon circumference. The prevalence of fetlock tufts of hair, chestnuts, ergots, and anatomically normal bulges in the pastern region also increased significantly with the clinical degree of severity. Furthermore the study revealed that the clinical degree of severity depended on the hygienic conditions of the stables and of the ground where the horses were kept outdoors.

[The development of verrucous pastern dermatitis syndrome in heavy draught horses. Part I: Review of the literature]. / Zur Entstehung von Warzenmauke bei Kaltblutpferden. Teil I: Literaturübersicht.

Verrucous pastern dermatitis is a chronic hyperplastic dermatopathy of the feet of horses which is characterized by a greasy, odorous coating of the skin and, in advanced stages, by clearly demarcated calluses and wart-like proliferations. The disease occurs almost exclusively in cold-blooded and other heavy horses, with certain breeds affected most frequently. It is considered a distinct disease entity within the framework of pastern dermatitis syndrome. There is no consensus in the literature about relationship of the disease to the sex and age of the horse. Horses with a high cannon circumference and pronounced fetlock tufts of hair seem to be affected most severely. In chiefly anecdotal reports the cause of the disease or its aggravation has been ascribed to housing conditions and environmental influences, chemicals, mechanical insults, feeding, or infections with Chorioptes skin mites. It thus seems likely that the disease is affected by a variety of factors. Although verrucous pastern dermatitis has been known for hundreds of years, its etiology and pathogenesis remain unclear.

Inheritance of guttural pouch tympany in the arabian horse.

The objective of the present study was to analyze the mode of inheritance of guttural pouch tympany (GPT) using pedigrees of Arabian horses. Complex segregation analyses were employed to test for the significance of nongenetic transmission and for monogenic, polygenic, and mixed monogenic-polygenic modes of inheritance. Horses affected by GPT comprised 27 Arabian purebred foals. Of these 27 animals, 22 were patients at the Clinic for Horses, School of Veterinary Medicine Hannover, Hannover, Germany, between 1994 and 2001 and 5 Arabian foals were from stud farms. Information on the pedigrees of these patients allowed us to classify the affected foals into four families with a total of 276 animals. The regressive logistic model analysis took into account the nonrandomness of the pedigrees through multiple single ascertainment correction. The complex segregation analysis showed that, among all other models employed, a polygenic and a mixed monogenic-polygenic model best explained the segregation of Arabian foals with GPT. Models including only nongenetic distributions and monogenic inheritance could be significantly rejected. This is the first report in which a genetic component could be shown to be responsible for GPT in horses.

[Current status and future potentials of multislice computed tomography]. / Heutiger Stand und zukünftige Entwicklungen in der Mehrschichtcomputertomographie.

This overview article gives a short introduction into present status and future potential of multislice computed tomography. The main benefits of established 4- to 16-slice CT systems are larger volume coverage, better utilization of the X-ray tube output and above all improved transverse resolution. Spiral examinations with 16 submillimeter slices are a breakthrough on the way towards isotropic scanning for routine applications. ECG-controlled CT-examinations of the heart benefit from both the improved temporal and spatial resolution of the new generation of 16-slice CT systems. Compared to 4-slice scanners, cardiac examinations are clinically more robust. The most important potential for improvement of multislice cardiac CT is a further enhancement of temporal resolution which requires increased gantry rotation speed for robust clinical performance. Combined systems such as CT PET scanners will gain increasing importance in the near future. In general radiology the race for more slices will continue, finally leading to the introduction of CT systems with area-detectors.

Retrospective analysis of 50 cases of guttural pouch tympany in foals.

Between 1994 and 2001, guttural pouch tympany was diagnosed in 51 foals; there were approximately three times as many fillies as colts, of Arabian, different German warmblood breeds and Western horse breeds. There were significantly more Arabian and paint horse foals than expected in comparison with the breed distribution of the foals hospitalised at the Clinic for Horses. The foals' breed and sex did not influence the age of onset, the type and severity of the clinical signs or the recurrence rate. A surgical laser technique was used on 50 of the foals; in 35 cases only one surgical treatment was necessary, in seven cases a second operation was required during the foal's initial period of hospitalisation, and in eight cases a second operation was performed during a second period of hospitalisation. Long-term follow-up information was obtained for 44 of the 50 treated horses; 24 of them were under two years of age and 20 were over two years of age. In six horses, no follow-up information was available. Four horses were euthanased for reasons unrelated to the condition or its treatment. The horses over two years of age were in training or were being used for competitions in dressage or jumping or for breeding purposes, and in only one of them was an adventitious respiratory noise reported. All the horses up to two years of age were reported to be healthy.

[Population genetic analysis of the heritability of gutteral pouch tympany in Arabian purebred foals]. / Populationsgenetische Untersuchung zur Erblichkeit der Luftsacktympanie beim Arabischen Vollblutfohlen.

The objective of the present study was to analyse the importance of the influences of the sex, inbreeding coefficient and the additive genetic contribution to the occurrence of guttural pouch tympany in Arabian foals. Horses affected by guttural pouch tympany were ascertained in the Clinic for Horses, School of Veterinary Medicine Hannover. The data comprised 27 Arabian purebred foals with guttural pouch tympany. Of these 27 animals 22 were patients of the Clinic for Horses between 1994 and 2001 and 5 Arabian foals were sampled on the studs. Information on the pedigrees of these patients allowed us to sort in the affected foals into four families with a total of 276 animals. Female foals were more often affected by guttural pouch tympany. The difference was 11.9% in favour of female foals. The size of the inbreeding coefficient was not important for the occurrence of guttural pouch tympany. The heritability estimate for the frequency of guttural pouch tympany using a threshold model was 0.49 +/- 0.28. This is the first report that could show a genetic component responsible for guttural pouch tympany in foals.

Image reconstruction and performance evaluation for ECG-gated spiral scanning with a 16-slice CT system.

We present an image reconstruction approach and a performance evaluation for ECG-gate cardiac spiral scanning with recently introduced 16-slice CT equipment. We present an extension of the Adaptive Cardio Volume (ACV) reconstruction approach for ECG-gated multislice spiral scanning. We discuss the image z reformation introduced to control the spiral slice width of the final images and give an overview of the reformation functions chosen. We investigate image quality and discuss the maximum number of slices that can be reconstructed without severe cone-beam artifacts. Slice sensitivity profiles (SSPs) and transverse resolution are evaluated as a function of the patient's heart rate. We demonstrate the influence of slice width on the visualization of stents and plaques and show the impact of reduced gantry rotation time (0.42 s) on temporal resolution. Deviating from general purpose spiral scanning cone-beam reconstruction is not required for ECG-gated cardiac CT with up to 16 slices. Using the ACV approach with image reformation, SSPs are well defined and independent of the patient's heart rate. With 0.75 mm collimated slice width, the measured full width at half-maximum (FWHM) of the smallest reconstructed slice is about 0.83 mm. Using this slice width and overlapping image reconstruction, cylindrical holes 0.6-0.7 mm in diameter can be resolved in a z-resolution phantom. Adequate visualization of the coronary arteries requires reconstruction slice widths not larger than 1.5 mm. Visualization of stents and severe calcifications is significantly improved with sub-mm slice width. Experimental evidence for the theoretically predicted temporal resolution and for the variation of temporal resolution depending on the position in the field of measurement (FOM) is presented. With 0.42 s gantry rotation temporal resolution reaches its optimum of 105 ms in the center of the FOM at 81 bpm. First scans on human subjects demonstrate the potential to expand the range of heart rates accessible to routine clinical examinations. A 16-slice platform can cover the heart with sub-mm slices within short breath-hold times, allowing for improved cardiac imaging due to isotropic sub-mm spatial resolution.

[Experimental studies on the therapy of epiglottis hypoplasia in horses--transendoscopic injection of collagen and polytetrafluoroethylene]. / Experimentelle Studie zur Therapie der Epiglottishypoplasie beim Pferd--Transendoskopische Injektion von Kollagen und Polytetrafluorethylen.

Epiglottic augmentation by transendoscopic injection of an implant material was performed on ten clinically healthy horses. In six cases bovine collagen (Zyplast) was used, in the remaining four horses the injection was done with polytetrafluorethylene (PTFE-Paste). The results of the surgery were observed endoscopically and by contrast radiography. Using the radiographs, epiglottic length and thickness were measured. For necropsy and histologic assessment the horses, three and two animals of the two groups, were euthanized at three and 12 weeks after surgery. The data obtained from the measurements at necropsy were correlated with those from the radiographs. The minimal invasive technique was very easy to perform with the bovine collagen while PTFE was less suitable for the transendoscopic injection. The data concerning the epiglottic length as well as its thickness measured on the radiographs correlated well to those obtained from the measurements at necropsy. After injection of collagen as well as PTFE an organisation of the implant was noticed histologically, which increased in accordance with the increasing time after injection. As far as the collagen implant is concerned, there was fibrous granulation tissue accompanied by an inflammatory reaction consisting mainly of lymphocytes and histiocytes. In contrast the injection of PTFE led to the development of a foreign body granuloma. In addition, some cases showed ulcers. Both implant materials led to an increase in epiglottic thickness, so that one can expect an improvement in its stability which could be of benefit to the therapy of epiglottic hypoplasia. But this increase in thickness had its maximum level directly after injection and declined over the period observed. Still, especially in the case of the collagen used here, the development of a fibrous granulation tissue and the immigration of fibroblasts and fibrocytes into the implant indicates that there is a stabilisation to some extent. Bovine collagen was proven to be highly suitable for transendoscopic injection. Although there is report about good clinical results using PTFE via laryngotomy, this material seems to be unsuitable for the transendoscopic technique due to the circumstances that lead to a higher number of complications.

Detection of coronary artery stenoses with multislice helical CT angiography.

OBJECTIVES: The authors compared multislice CT angiography and selective angiography for the assessment of coronary artery disease. METHODS: In 28 patients, the presence and degree of coronary artery stenoses were determined in coronary segments prepared with beta-blocker for good image quality with multislice CT. RESULTS: In 187 coronary artery segments, sensitivity, specificity, and negative predictive value for the detection of stenoses >50% with multislice CT angiography were 81%, 90%, and 97%, respectively. The agreement for determining the degree of stenoses with multislice CT angiography and selective coronary angiography was only moderate (kappa = 0.58). CONCLUSIONS: Because of the limited spatial resolution, it is not possible with multislice CT angiography to determine the degree the coronary artery stenoses precisely. However, the high negative predictive value indicates that multislice CT may be a suitable tool to reliably rule out coronary artery disease.

Non-invasive coronary angiography with high resolution multidetector-row computed tomography. Results in 102 patients.

AIMS: A new generation of multidetector-row CT (MDCT) scanners allows complete coronary coverage using retrospective ECG gating and 1mm slices. The purpose of this study was to investigate the potential of high resolution MDCT angiography with retrospective gating for detection of coronary artery stenoses. METHODS AND RESULTS: A total of 102 patients underwent both conventional and MDCT coronary angiography. After intravenous injection of a non-ionic contrast medium the entire heart was scanned within a single breath hold using 1mm slices. All MDCT data sets were reconstructed with retrospective gating at 20% to 80% in increments of 10% relative to the cardiac cycle. Two blinded independent reviewers analysed image quality for segments 1-4 (right coronary artery), 5-8 (left main, left anterior descending), and 11, 12 (left circumflex). These segments were evaluated for the presence or absence of significant (>or=50%) stenoses. The results were compared with those of invasive coronary angiography in a blinded fashion. Overall sensitivity for the detection of significant stenoses (>or=50%) were 0.86 (reader 1) and 0.93 (reader 2), specificity 0.96 (reader 1) and 0.97 (reader 2), negative predictive value 0.98 (reader 1) and 0.99 (reader 2). CONCLUSIONS: High resolution MDCT angiography with retrospective gating permits the non-invasive detection of coronary artery stenoses with high accuracy if image quality is optimized for each of the three major coronary arteries.