More losses than gains during one century of plant biodiversity change in Germany.

Long-term analyses of biodiversity data highlight a 'biodiversity conservation paradox': biological communities show substantial species turnover over the past century1,2, but changes in species richness are marginal1,3-5. Most studies, however, have focused only on the incidence of species, and have not considered changes in local abundance. Here we asked whether analysing changes in the cover of plant species could reveal previously unrecognized patterns of biodiversity change and provide insights into the underlying mechanisms. We compiled and analysed a dataset of 7,738 permanent and semi-permanent vegetation plots from Germany that were surveyed between 2 and 54 times from 1927 to 2020, in total comprising 1,794 species of vascular plants. We found that decrements in cover, averaged across all species and plots, occurred more often than increments; that the number of species that decreased in cover was higher than the number of species that increased; and that decrements were more equally distributed among losers than were gains among winners. Null model simulations confirmed that these trends do not emerge by chance, but are the consequence of species-specific negative effects of environmental changes. In the long run, these trends might result in substantial losses of species at both local and regional scales. Summarizing the changes by decade shows that the inequality in the mean change in species cover of losers and winners diverged as early as the 1960s. We conclude that changes in species cover in communities represent an important but understudied dimension of biodiversity change that should more routinely be considered in time-series analyses.

A novel approach to urban turtle sampling: Assessing Hookless Fishing with clip and two conventional methods.

To address urban turtle sampling challenges, we presented Hookless fishing with clip, a cost-effective method for sampling this important group. Effectiveness, biases and potential advantages were analysed in comparison to two commonly used methods (funnel trap and hand capture). Fieldwork was conducted between August and November/2021 in four areas in Brazil, using the three methods simultaneously. A total of 195 turtles from four species (Phrynops geoffroanus, Hydromedusa tectifera, Trachemys dorbigni and T. scripta elegans) were captured. Funnel trap demonstrate a significantly higher capture than hand capture, while Hookless fishing showed no significant difference in captures compared to funnel trap. The highest catch per unit effort values were observed for the new method (0.37) and the funnel trap (0.34). Despite being widely used, funnel traps were the only method to exhibit male bias. Our findings revealed that Hookless fishing with clip exhibited remarkable capture efficiency, cost-effectiveness, and ease of transport and utilization; however, it requires operator presence. Nevertheless, the proposed method, both as the primary or auxiliary approach, appears efficient in enhancing captures and reducing costs and risks. This innovative method has the potential to assist researchers studying omnivorous and carnivores freshwater turtles in environments worldwide, especially in human settlements.

Nasal and tracheobronchial nitric oxide production and its influence on oxygenation in horses undergoing total intravenous anaesthesia.

BACKGROUND: The present study aimed to investigate the effect of endotracheal intubation on nasal and tracheal endogenous NO concentrations, gas exchange and oxygenation in horses undergoing general anaesthesia. In many species a major part of physiological nitric oxide (NO) production takes place in the nasopharynx. Inhaled NO acts as a pulmonary vasodilator and regulates lung perfusion and endotracheal intubation bypasses the nasopharynx. Six horses were randomly assigned to either the "intubated" (INT) or the "non-intubated" (nINT) treatment group. Horses were premedicated with dexmedetomidine (5 µg/kg IV). Anaesthesia was induced with 2.5 mg/kg ketamine and 0.05 mg/kg diazepam IV, and it was maintained by administration of a triple-drip (100 mg/kg/h guaifenesin, 4 mg/kg/h ketamine, 7 µg/kg/h dexmedetomidine). The horses were spontaneously breathing room air. Heart rate, cardiac output, arterial blood pressure, pulmonary arterial blood pressures and respiratory rate were recorded during a 100-min anaesthesia period. Arterial, venous and mixed venous blood samples were taken every 10 minutes and analysed for partial pressure of oxygen (PO2) and carbon dioxide (PCO2), oxygen saturation and haemoglobin content. Standard oxygenation indices were calculated. Nasal and tracheal endogenous NO concentration was determined by chemiluminescence. RESULTS: Cardiovascular variables, respiratory rate, PO2, PCO2, oxygen saturation, haemoglobin content, CaO2, O2ER, P(a-ET)CO2 and Qs/Qt did not differ significantly between the two treatment groups. The P(A-a)O2 was significantly higher in INT (6.1 ± 0.3 kPa) compared to nINT (4.9 ± 0.1 kPa) (p = 0.045), respectively. The nasal (8.0 ± 6.2 ppb) and tracheal (13.0 ± 6.3 ppb) endogenous NO concentration differed significantly in INT (p = 0.036), but not in nINT (nasal: 16.9 ± 9.0 ppb; tracheal: 18.5 ± 9.5 ppb) (p = 0.215). CONCLUSION: Endotracheal intubation reduces the nasal and tracheal endogenous NO concentration. The influence on pulmonary gas exchange and oxygenation is negligible in horses breathing room air.

Range dynamics of mountain plants decrease with elevation.

Many studies report that mountain plant species are shifting upward in elevation. However, the majority of these reports focus on shifts of upper limits. Here, we expand the focus and simultaneously analyze changes of both range limits, optima, and abundances of 183 mountain plant species. We therefore resurveyed 1,576 vegetation plots first recorded before 1970 in the European Alps. We found that both range limits and optima shifted upward in elevation, but the most pronounced trend was a mean increase in species abundance. Despite huge species-specific variation, range dynamics showed a consistent trend along the elevational gradient: Both range limits and optima shifted upslope faster the lower they were situated historically, and species' abundance increased more for species from lower elevations. Traits affecting the species' dispersal and persistence capacity were not related to their range dynamics. Using indicator values to stratify species by their thermal and nutrient demands revealed that elevational ranges of thermophilic species tended to expand, while those of cold-adapted species tended to contract. Abundance increases were strongest for nutriphilous species. These results suggest that recent climate warming interacted with airborne nitrogen deposition in driving the observed dynamics. So far, the majority of species appear as "winners" of recent changes, yet "losers" are overrepresented among high-elevation, cold-adapted species with low nutrient demands. In the decades to come, high-alpine species may hence face the double pressure of climatic changes and novel, superior competitors that move up faster than they themselves can escape to even higher elevations.

Effects of isoflurane, remifentanil and dexmedetomidine on selected EEG parameters derived from a Narcotrend Monitor before and after nociceptive stimulation at different MAC multiples in cats.

BACKGROUND: The aim of this prospective and complete cross-over study was to evaluate the effects of isoflurane, remifentanil and dexmedetomidine on EEG parameters derived from the Narcotrend® Monitor before and after nociceptive stimulation at different isoflurane MAC (minimal alveolar concentration) multiples. Seven adult European Domestic Short Hair cats were used. Each cat went through 3 experimental treatments. Group I received isoflurane, group IR received isoflurane and a constant rate infusion (CRI) of remifentanil (18 µg/kg/h IV), and group ID received isoflurane and a CRI of dexmedetomidine (3 µg/kg/h IV). The isoflurane MAC in each group was determined via supramaximal electrical stimulation. The EEG parameters were derived by a Narcotrend Monitor at specific time points before and after nociceptive stimulation at 0.75, 1.0 and 1.5 MAC. The depth of anaesthesia was also assessed by a clinical score. RESULTS: The mean MAC sparing effects in group IR and group ID were 9.8 and 55.2%, respectively. The best correlation of EEG and MAC multiples was found for the Narcotrend Index (NI) in group I (r = - 0.67). The NI was also able to differentiate between 0.75 MAC and 1.5 MAC in group IR. Spectral edge frequency had a lower correlation with MAC multiples in group I (r = - 0.62) but was able to differentiate between 0.75 MAC and 1.5 MAC in groups I and IR, and between 1.0 MAC and 1.5 MAC in group IR. Narcotrend Index, SEF 95 and MF increased significantly after nociceptive stimulation at 1.0 MAC in group I, and SEF 95 increased significantly at 0.75 MAC in group ID. The clinical score correlated closer than any of the EEG parameters with MAC in all groups, with highest correlation values in group I (r = - 0.89). Noxious stimulation led to a significant increase of the clinical score at 0.75 MAC and 1.0 MAC in group I. CONCLUSIONS: The EEG parameters derived from the Narcotrend Monitor show correlation to isoflurane MAC multiples in cats, but the anaesthetic protocol and especially the addition of dexmedetomidine have great influence on the reliability. The Narcotrend Monitor can be used as an additional tool to assess anesthetic depth in cats.

Comparison between head-tail-rope assisted and unassisted recoveries in healthy horses undergoing general anesthesia for elective surgeries.

OBJECTIVE: To compare attempts to stand, duration, quality, and occurrence of injuries between head-tail rope assistance and unassisted recoveries in healthy horses undergoing general anesthesia for elective surgeries. STUDY DESIGN: Randomized, prospective, clinical trial. METHODS: Three hundred one healthy horses undergoing elective surgeries were randomly assigned to recover with head-tail rope assistance (group A) or unassisted (group U); 305 recoveries (group A, n = 154; group U, n = 151) were analyzed. Anesthesia was maintained with isoflurane and triple drip. For each recovery, attempts to stand, duration, quality, and recovery-associated injuries were recorded. Data were analyzed by linear regression and analysis of covariance. RESULTS: Anesthesia duration was similar between groups (mean ± SD, 70 ± 29 minutes). Compared with group U, group A had fewer attempts to stand (median [range], group A = 1 [1-7] vs group U = 3 [1-34]) and shorter duration of recovery (mean ± SD, A = 36 ± 12 minutes vs U = 41 ± 15 minutes). Recovery quality in group A (28 points [15-70]) was better than that in group U (38 points [11-87]). More horses had recovery-associated injuries in group U (9 horses) compared with group A (2 horses). One horse per group was euthanized. CONCLUSION: Head-tail rope assistance reduced standing attempts, shortened recovery duration, improved recovery quality, and reduced recovery-associated minor injuries after general anesthesia for elective surgery in healthy horses. Fatalities could not be prevented. CLINICAL SIGNIFICANCE: Head-tail rope assistance may improve recovery in healthy horses after short-duration elective surgeries with isoflurane and triple drip.

Randomized controlled trial of pregabalin for analgesia after surgical treatment of intervertebral disc disease in dogs.

OBJECTIVE: To assess the effect of perioperative pregabalin on pain behavior in dogs after intervertebral disc surgery. STUDY DESIGN: Prospective, randomized, controlled clinical trial with a blinded observer. ANIMALS: Forty-six client-owned dogs undergoing intervertebral disc surgery. METHODS: Dogs were randomly assigned to two groups, with the placebo group receiving opioids alone and the pregabalin group receiving opioids plus pregabalin. Opioid analgesia consisted of 0.6 mg/kg l-methadone given intravenously at anesthetic induction, followed by 0.2 mg/kg given at 8, 16, and 24 hours after extubation and fentanyl patches applied at the end of surgery. Pregabalin was given orally (4 mg/kg) 1 hour before anesthesia, followed by postoperative treatment three times per day (4 mg/kg) for 5 days. The outcome measures were the treatment-group differences in peri-incisional mechanical sensitivity and Glasgow Composite Measure Pain Scale (CMPS-SF) assessed during the first 5 postoperative days. Pregabalin serum concentrations were measured after 24, 72, and 120 hours. RESULTS: Pregabalin reduced pain levels in the treatment group by a mean of 2.5 CMPS-SF units (95% confidence interval [CI] = -3.19 to -1.83, P < .001) compared with the control group during the study period. Pregabalin increased the mechanical nociceptive threshold by a mean of 6.89 N per day (95% CI = 1.87-11.92, P < .001) and of 7.52 N per day (95% CI = 2.29-12.77, P < .001) during the study period, depending on location. Mean levels of serum pregabalin were 5.1, 4.71, and 3.68 µg/mL at 24, 72, and 120 hours postoperatively, respectively. CONCLUSION: Postoperative signs of pain after surgical treatment of intervertebral disc herniation (IVDH) were reduced when dogs received perioperative pregabalin rather than opioids alone. CLINICAL SIGNIFICANCE: Perioperative pregabalin reduces postoperative pain after surgical treatment of IVDH.

Experimental study on the effects of isoflurane with and without remifentanil or dexmedetomidine on heart rate variability before and after nociceptive stimulation at different MAC multiples in cats.

BACKGROUND: Heart rate variability (HRV) provides information about autonomic nervous system (ANS) activity and is therefore a possible tool with which to assess anaesthetic depth. The aim of the present study was to evaluate the effects of isoflurane, remifentanil and dexmedetomidine on HRV before and after nociceptive stimulation at different anaesthetic depths. Seven healthy domestic short-hair cats were used, and each cat was anaesthetized three times - group I with isoflurane alone, group IR with isoflurane and a constant rate infusion (CRI) of remifentanil (18 µg/kg/h), and group ID with isoflurane and a CRI of dexmedetomidine (3 µg/kg/h). Minimum alveolar concentration (MAC) values were determined via electrical supramaximal nociceptive stimulation for each treatment group. Nociceptive stimulation was repeated at 3 different MAC multiples (0.75, 1.0 and 1.5 MAC), and electrocardiographic recordings were performed for 3 min before and after stimulation. Only the 1 min epochs were used for further statistical analysis. Electrocardiographic data were exported for offline HRV analysis. RESULTS: The mean isoflurane MAC ± standard deviation (SD) was 1.83 ± 0.22 vol% in group I, 1.65 ± 0.13 vol% in group IR and 0.82 ± 0.20 vol% in group ID. Nociception was indicated by several HRV parameters, however, with high variability between treatments. The best correlation with MAC was found for the SD of heart rate (STD HR) in group I (rs = - 0.76, p = 0.0001, r2 = 0.46). STD HR was also able to distinguish 0.75 MAC from 1.5 MAC and 1.0 MAC from 1.5 MAC in group I, as well as 0.75 MAC from 1.5 MAC in group ID. CONCLUSIONS: The choice of anaesthetic protocol influences the HRV parameters in cats. Frequency domain parameters respond to nociception at lower MAC levels. The STD HR has the potential to provide additional information for the assessment of anaesthetic depth in isoflurane-anaesthetized cats. The utility of HRV analysis for the assessment of anaesthetic depth in cats is still questionable.

Distribution pattern of anurans from three mountain complexes in southeastern Brazil and their conservation implications.

Biogeographic tools support spatial distribution pattern hypotheses and help to determine priority areas for conservation. Our aim was to verify biogeographic patterns for anurans in three mountain complexes in southeastern Brazil, as well as to discuss the status of species conservation recorded and the biogeographical units evaluated. We selected 16 areas distributed in the Serra da Mantiqueira complex, south of Serra do Espinhaço and Serra da Canastra. We used the occurrence (geographic coordinates) of each species in the localities to determine areas of endemism applying the Endemicity Analysis method. We also tested whether similarity between areas was explained by geographic distance (Multiple Regression on distance Matrices-MRM). The Serra do Itatiaia, Serra da Canastra, Plateau of Poços de Caldas and Serra do Cipó were the areas that presented the highest number of species restricted to them. Through the Endemicity Analysis, we identified four areas of endemism with higher scores. The MRM revealed that the geographic distance explained 41% of species dissimilarity between areas. Most of the endemic species from these areas have inaccurate conservation statuses (data deficient or unevaluated). These results highlight the need for greater research efforts towards understanding species restricted by distribution, as well as the priority in conserving these endemic areas.

The CRAC cohort model: A computerized low cost registry of interventional cardiology with daily update and long-term follow-up.

OBJECTIVES: To assess the reliability and low cost of a computerized interventional cardiology (IC) registry to prospectively and systematically collect high-quality data for all consecutive coronary patients referred for coronary angiogram or/and coronary angioplasty. BACKGROUND: Rigorous clinical practice assessment is a key factor to improve prognosis in IC. A prospective and permanent registry could achieve this goal but, presumably, at high cost and low level of data quality. One multicentric IC registry (CRAC registry), fully integrated to usual coronary activity report software, started in the centre Val-de-Loire (CVL) French region in 2014. METHODS: Quality assessment of CRAC registry was conducted on five IC CathLab of the CVL region, from January 1st to December 31st 2014. Quality of collected data was evaluated by measuring procedure exhaustivity (comparing with data from hospital information system), data completeness (quality controls) and data consistency (by checking complete medical charts as gold standard). Cost per procedure (global registry operating cost/number of collected procedures) was also estimated. RESULTS: CRAC model provided a high-quality level with 98.2% procedure completeness, 99.6% data completeness and 89% data consistency. The operating cost per procedure was €14.70 ($16.51) for data collection and quality control, including ST-segment elevation myocardial infarction (STEMI) preadmission information and one-year follow-up after angioplasty. CONCLUSIONS: This integrated computerized IC registry led to the construction of an exhaustive, reliable and costless database, including all coronary patients entering in participating IC centers in the CVL region. This solution will be developed in other French regions, setting up a national IC database for coronary patients in 2020: France PCI.

Chondrosarcoma: A Rare Misfortune in Aging Human Cartilage? The Role of Stem and Progenitor Cells in Proliferation, Malignant Degeneration and Therapeutic Resistance.

Unlike other malignant bone tumors including osteosarcomas and Ewing sarcomas with a peak incidence in adolescents and young adults, conventional and dedifferentiated chondrosarcomas mainly affect people in the 4th to 7th decade of life. To date, the cell type of chondrosarcoma origin is not clearly defined. However, it seems that mesenchymal stem and progenitor cells (MSPC) in the bone marrow facing a pro-proliferative as well as predominantly chondrogenic differentiation milieu, as is implicated in early stage osteoarthritis (OA) at that age, are the source of chondrosarcoma genesis. But how can MSPC become malignant? Indeed, only one person in 1,000,000 will develop a chondrosarcoma, whereas the incidence of OA is a thousandfold higher. This means a rare coincidence of factors allowing escape from senescence and apoptosis together with induction of angiogenesis and migration is needed to generate a chondrosarcoma. At early stages, chondrosarcomas are still assumed to be an intermediate type of tumor which rarely metastasizes. Unfortunately, advanced stages show a pronounced resistance both against chemo- and radiation-therapy and frequently metastasize. In this review, we elucidate signaling pathways involved in the genesis and therapeutic resistance of chondrosarcomas with a focus on MSPC compared to signaling in articular cartilage (AC).

Greater temperature sensitivity of plant phenology at colder sites: implications for convergence across northern latitudes.

Warmer temperatures are accelerating the phenology of organisms around the world. Temperature sensitivity of phenology might be greater in colder, higher latitude sites than in warmer regions, in part because small changes in temperature constitute greater relative changes in thermal balance at colder sites. To test this hypothesis, we examined up to 20 years of phenology data for 47 tundra plant species at 18 high-latitude sites along a climatic gradient. Across all species, the timing of leaf emergence and flowering was more sensitive to a given increase in summer temperature at colder than warmer high-latitude locations. A similar pattern was seen over time for the flowering phenology of a widespread species, Cassiope tetragona. These are among the first results highlighting differential phenological responses of plants across a climatic gradient and suggest the possibility of convergence in flowering times and therefore an increase in gene flow across latitudes as the climate warms.

Effects of controlled hypoxemia or hypovolemia on global and intestinal oxygenation and perfusion in isoflurane anesthetized horses receiving an alpha-2-agonist infusion.

BACKGROUND: Aim of this prospective experimental study was to assess effects of systemic hypoxemia and hypovolemia on global and gastrointestinal oxygenation and perfusion in anesthetized horses. Therefore, we anesthetized twelve systemically healthy warmblood horses using either xylazine or dexmedetomidine for premedication and midazolam and ketamine for induction. Anesthesia was maintained using isoflurane in oxygen with either xylazine or dexmedetomidine and horses were ventilated to normocapnia. During part A arterial oxygen saturation (SaO2) was reduced by reducing inspiratory oxygen fraction in steps of 5%. In part B hypovolemia was induced by controlled arterial exsanguination via roller pump (rate: 38 ml/kg/h). Mean arterial blood pressure (MAP), heart rate, pulmonary artery pressure, arterial and central venous blood gases and cardiac output were measured, cardiac index (CI) was calculated. Intestinal microperfusion and oxygenation were measured using laser Doppler flowmetry and white-light spectrophotometry. Surface probes were placed via median laparotomy on the stomach, jejunum and colon. RESULTS: Part A: Reduction in arterial oxygenation resulted in a sigmoid decrease in central venous oxygen partial pressure. At SaO2 < 80% no further decrease in central venous oxygen partial pressure occurred. Intestinal oxygenation remained unchanged until SaO2 of 80% and then decreased. Heart rate and pulmonary artery pressure increased significantly during hypoxemia. Part B: Progressive reduction in circulating blood volume resulted in a linear decrease in MAP and CI. Intestinal perfusion was preserved until blood loss resulted in MAP and CI lower 51 ± 5 mmHg and 40 ± 3 mL/kg/min, respectively, and then decreased rapidly. CONCLUSIONS: Under isoflurane, intestinal tissue oxygenation remained at baseline when arterial oxygenation exceeded 80% and intestinal perfusion remained at baseline when MAP exceeded 51 mmHg and CI exceeded 40 mL/kg/min in this group of horses. TRIAL REGISTRY NUMBER: 33.14-42,502-04-14/1547.

Effect of butorphanol, midazolam or ketamine on romifidine based sedation in horses during standing cheek tooth removal.

BACKGROUND: Standing surgery, especially dental procedures, are commonly performed in horses. This leads to an increasing demand for reliable sedation protocols. Therefore, it was the purpose of this study to investigate the influence of butorphanol, midazolam or ketamine on romifidine based sedation in horses during cheek tooth removal. METHODS: Forty horses presented for tooth extraction were divided in four groups using matched pair randomization. Group R was sedated with romifidine (bolus 0.03 mg/kg, followed by a constant rate infusion (CRI) 0.05 mg/kg/h) and group RB with romifidine (same dose) and butorphanol (0.02 mg/kg; CRI 0.04 mg/kg/h). Group RM received romifidine (same dose) and midazolam (0.02 mg/kg; CRI 0.06 mg/kg/h) whereas group RK was administered romifidine (same dose) and ketamine (0.5 mg/kg; CRI 1.2 mg/kg/h). If sedation was not adequate a top up bolus of romifidine (0.01 mg/kg) was administered. The quality of sedation and the conditions for tooth extraction, the level of ataxia, chewing, head and tongue movement were evaluated by using a scoring system. The investigator was blinded to the applied sedation protocol. Furthermore, serum cortisol concentrations before, during and after the procedure were analyzed to gain more information about the stress level of the horses. RESULTS: Horses in group RM showed significantly less chewing and tongue activity compared to horses sedated with romifidine alone or with butorphanol additionally, but also significantly higher levels of ataxia. The quality of sedation was significantly better if romifidine was administered in combination with ketamine compared to romifidine alone. Furthermore, horses of group RK needed less additional romifidine boli compared to all other groups. Blood cortisol concentrations during surgery in groups RB and RM remained unchanged. Horses of group R showed higher cortisol concentrations during sedation compared to horses of groups RB and RM. CONCLUSION: Romifidine alone at an initial bolus dose of 0.03 mg/kg followed by a constant rate infusion of 0.05 mg/kg/h was insufficient to obtain an adequate level of sedation and led to increased stress levels, whereas the addition of butorphanol inhibited the stress response. The combination of romifidine with either midazolam or ketamine improved sedation quality and surgical conditions.

Controlled mechanical ventilation with constant positive end-expiratory pressure and alveolar recruitment manoeuvres during anaesthesia in laterally or dorsally recumbent horses.

OBJECTIVE: To compare the effects of controlled mechanical ventilation (CMV) and constant positive end-expiratory pressure (PEEP) and interposed recruitment manoeuvres (RMs) with those of CMV without PEEP on gas exchange during general anaesthesia and the early recovery period. STUDY DESIGN: Prospective, randomized clinical trial. ANIMALS: A total of 48 Warmblood horses undergoing elective surgery in lateral (Lat) (n = 24) or dorsal (Dors) (n = 24) recumbency. METHODS: Premedication (romifidine), induction (diazepam and ketamine) and maintenance (isoflurane in oxygen) were identical in all horses. Groups Lat- CMV and Dors-CMV (each n = 12) were ventilated using CMV. Groups Lat-RM and Dors-RM (each n = 12) were ventilated using CMV with constant PEEP (10 cmH2O) and intermittent RMs (three consecutive breaths with peak inspiratory pressure of 60 cmH2O, 80 cmH2O and 60 cmH2O, respectively). RMs were applied as required to maintain PaO2 at > 400 mmHg (> 53.3 kPa). Dobutamine was given to maintain mean arterial blood pressure at > 60 mmHg. Physiological parameters were recorded every 10 minutes. Arterial blood gases were measured intra- and postoperatively. Statistical analyses were conducted using analyses of variance (anova),t tests and the Mann-Whitney U-test. RESULTS: Horses in Dors-RM had higher PaO2 values [478 ± 35 mmHg (63.7 ± 4.6 kPa)] than horses in Dors-CMV [324 ± 45 mmHg (43.2 ± 6 kPa)] during anaesthesia and the early recovery period. There were no differences between horses in groups Lat-CMV and Lat-RM. Other measured parameters did not differ between groups. CONCLUSIONS AND CLINICAL RELEVANCE: Ventilation with CMV, constant PEEP and interposed RM provided improved arterial oxygenation in horses in dorsal recumbency that lasted into the early recovery period, but had no benefit in horses in lateral recumbency. This mode of ventilation may provide a clinically practicable method of improving oxygenation in anaesthetized horses, especially in dorsal recumbency.

Influence of tramadol on acute thermal and mechanical cutaneous nociception in dogs.

OBJECTIVE: The aim of the study was to evaluate the influence of tramadol on acute nociception in dogs. STUDY DESIGN: Experimental, blinded, randomized, crossover study. ANIMALS: Six healthy laboratory Beagle dogs. METHODS: Dogs received three treatments intravenously (IV): isotonic saline placebo (P), tramadol 1 mg kg-1 (T1) and tramadol 4 mg kg-1 (T4). Thermal thresholds were determined by ramped contact heat stimulation (0.6 °C second-1) at the lateral thoracic wall. Mechanical thresholds (MT) were measured using a probe containing three blunted pins which were constantly advanced over the radial bone, using a rate of force increase of 0.8 N second-1. Stimulation end points were defined responses (e.g. skin twitch, head turn, repositioning, vocalization) or pre-set cut-out values (55 °C, 20 N). Thresholds were determined before treatment and at predetermined time points up to 24 hours after treatment. At each measurement point, blood was collected for determination of O-desmethyltramadol concentrations. The degree of sedation and behavioural side effects were recorded. Data were analysed by one-way anova and two-way anova for repeated measurements. RESULTS: Thermal nociception was not influenced by drug treatment. Mechanical nociception was significantly increased between P and T1 at 120 and 240 minutes, and between P and T4 at 30, 60, 240 and 420 minutes. T1 and T4 did not differ. O-desmethyltramadol (M1) maximum plasma concentrations (Cmax) were 4.2±0.8 ng mL-1 and 14.3±2.8 ng mL-1 for T1 and T4, respectively. Times to reach maximum plasma concentrations (Tmax) were 27.6±6.3 minutes for T1 and 32.1±7.8 minutes for T4. No sedation occurred. There were signs of nausea and mild to moderate salivation in both groups. CONCLUSION AND CLINICAL RELEVANCE: Tramadol was metabolized marginally to O-desmethyltramadol and failed to produce clinically relevant acute antinociception. Therefore, the use of tramadol for acute nociceptive pain is questionable in dogs.

Propofol-medetomidine-ketamine total intravenous anaesthesia in thiafentanil-medetomidine-immobilized impala (Aepyceros melampus).

OBJECTIVE: To characterize a propofol-medetomidine-ketamine total intravenous anaesthetic in impala (Aepyceros melampus). STUDY DESIGN: Prospective clinical study. ANIMALS: Ten adult female impala. MATERIALS AND METHODS: Impala were immobilized at 1253 m above sea level with 2.0 mg thiafentanil and 2.2 mg medetomidine via projectile darts. Propofol was given to effect (0.5 mg kg-1 boluses) to allow endotracheal intubation, following which oxygen was supplemented at 2 L minute-1. Anaesthesia was maintained with a constant-rate infusion of medetomidine and ketamine at 5 µg kg-1 hour-1 and 1.5 mg kg-1 hour-1, respectively, and propofol to effect (initially 0.2 mg kg-1 minute-1) for 120 minutes. The propofol infusion was titrated according to reaction to nociceptive stimuli every 15 minutes. Cardiopulmonary parameters were monitored continuously and arterial blood gas samples were analysed intermittently. After 120 minutes' maintenance, the thiafentanil and medetomidine were antagonized using naltrexone (10:1 thiafentanil) and atipamezole (5:1 medetomidine), respectively. RESULTS: All impala were successfully immobilized. The median dose [interquartile range (IQR)] of propofol required for intubation was 2.7 (1.9-3.3) mg kg-1. The propofol-medetomidine-ketamine combination abolished voluntary movement and ensured anaesthesia for the 120 minute period. Propofol titration showed a generally downward trend. Median (IQR) heart rate [57 (53-61) beats minute-1], respiratory rate [10 (9-12) breaths minute-1] and mean arterial blood pressure [101 (98-106) mmHg] were well maintained. Arterial blood gas analysis indicated hypoxaemia, hyper- capnia and acidaemia. Butorphanol (0.12 mg kg-1) was an essential rescue drug to counteract thiafentanil-induced respiratory depression. All impala regurgitated frequently during the maintenance period. Recovery was calm and rapid in all animals. Median (IQR) time to standing from antagonist administration was 4.4 (3.2-5.6) minutes. CONCLUSIONS AND CLINICAL RELEVANCE: A propofol-medetomidine-ketamine combination could provide adequate anaesthesia for invasive procedures in impala. The propofol infusion should begin at 0.2 mg kg-1 minute-1 and be titrated to clinical effect. Oxygen supplementation and airway protection with a cuffed endotracheal tube are essential.

CONTINUOUS INTRAVENOUS INFUSION ANESTHESIA WITH MEDETOMIDINE, KETAMINE, AND MIDAZOLAM AFTER INDUCTION WITH A COMBINATION OF ETORPHINE, MEDETOMIDINE, AND MIDAZOLAM OR WITH MEDETOMIDINE, KETAMINE, AND BUTORPHANOL IN IMPALA (AEPYCEROS MELAMPUS).

In order to develop a long-term anesthesia for flighty antelope species in field situations, two different protocols for induction and maintenance with an intravenous infusion were evaluated in wild-caught impala ( Aepyceros melampus ). Ten adult female impala were induced with two induction protocols: one consisted of 0.2 mg/kg medetomidine, 4 mg/kg ketamine, and 0.15 mg/kg butorphanol (MKB) and one consisted of 0.375 mg/kg etorphine, 0.2 mg/kg medetomidine, and 0.2 mg/kg midazolam (EMM). In both treatments, anesthesia was maintained with a continuous intravenous infusion (CII) at an initial dose rate of 1.2 µg/kg per hr medetomidine, 2.4 mg/kg per hr ketaminen and 36 µg/kg per hr midazolam. Partial reversal was achieved with naltrexone (2 : 1 mg butorphanol; 20 : 1 mg etorphine) and atipamezole (5 : 1 mg medetomidine). Evaluation of anesthesia included respiratory rate, heart rate, rectal temperature, arterial blood pressure, oxygen saturation, end tidal carbon dioxide tension, and tidal volume at 5-min intervals, palpebral reflex and response to painful stimuli at 15-min intervals, and arterial blood gases at 30-min intervals. Plasma cortisol concentration was determined after induction and before reversal. Duration and quality of induction and recovery were evaluated. EMM caused a faster induction of 9.5 ± 2.9 min compared to 11.0 ± 6.4 min in MKB. Recovery was also quicker in EMM (EMM: 6.3 ± 5.4 min; MKB: 9.8 ± 6.0 min). However, EMM also produced more cardiopulmonary side effects, including hypoxemia and hypercapnia, and calculated oxygenation indices (PaCO2-PETCO2) were worse than in MKB. One animal died after induction with EMM. The CII provided surgical anesthesia in 7 of 10 animals in MKB and in 9 of 9 animals in EMM for 120 min. In conclusion, the MKB induction protocol had advantages for prolonged anesthesia in impala with significantly less cardiopulmonary depression compared to EMM. The comparably decreased anesthetic depth could easily be adjusted by an increase of the CII.

Influence of metamizole on 1) minimal alveolar concentration of sevoflurane in dogs and 2) on thermal and mechanical nociception in conscious dogs.

OBJECTIVE: To determine the acute anti-nociceptive and the minimal alveolar concentration (MAC) sparing effects of metamizole sodiummonohydrate (dipyrone) in dogs for possible perioperative analgesia. STUDY DESIGN: Two groups of seven adult dogs were used in two separate randomised, blinded, controlled, cross-over studies. In each study, each dog received metamizole 50 mg kg(-1) intravenously (IV) and placebo (saline 0.9%) IV. METHODS: Sevoflurane MAC was determined using the bracketing technique and electrical stimulation (50 V, 50 Hz, 10 milliseconds) at a thoracic limb, before treatment and 1 and 4 hours post treatment. In conscious dogs, thermal thresholds were determined by ramped contact heat at the thoracic wall. Mechanical thresholds (MTs) were measured by constantly rising force pressing against the radial bone. Thresholds were determined pre and 45, 75, 105, 135, 165, 195, 225, 255, 285, 315, 345, 375, 435, 495, 555, 615, 675, 735 minutes and 24 hours post treatment. Parametric data were analyzed by analysis of variance for repeated measurements and paired t-tests. Friedman test was used for nonparametric data. Level of significance was set to <5%. RESULTS: Metamizole did not change MAC of sevoflurane significantly compared to baseline values [mean ± SD Vol%; 2.7 ± 0.5 (BL); 2.8 ± 0.6 (1 hour); 2.8 ± 0.4 (4 hours)] and placebo [2.8 ± 0.5 (BL); 2.9 ± 0.5 (1 hour); 2.9 ± 0.4 (4 hour)]. Metamizole caused a significant rise in % TE up to 105 minutes (66.5 ± 12.1%) and in MT up to 75 minutes (12.7 ± 5.0 N) compared to baseline (55 ± 10%; 7.9 ± 1.8 N). There were no significant differences between treatments. CONCLUSION AND CLINICAL RELEVANCE: Metamizole did not induce an anaesthetic sparing effect. In awake dogs metamizole induced only mild and short cutaneous anti-nociception. Metamizole as the sole analgesic drug in the perioperative periode is not recommended.