Two-dimensional shear wave elastography of liver in healthy dogs: anaesthesia as a source of variability

Two-dimensional shear wave elastography (2D-SWE) is a non-invasive method to quantitatively evaluate the liver sti ness (LS), allowing the detection of hepatic pathological changes in both dogs and humans. In dogs, some factors such as patient movement and respiration can cause artefacts and potential errors of measurements. Therefore, anaesthesia has been suggested to reduce the e ect of the movement on 2D-SWE in dogs. This study was performed to evaluate the in uence of an anaesthetic protocol on 2D-SWE measurements for assessment of LS in healthy dogs. Forty- ve dogs were included and subjected to anaesthesia: in 11 dogs, the 2D- SWE was performed both before and under anaesthesia, in 19 dogs, the 2D-SWE was per- formed only when they were awake and in 15 dogs, the examination was carried out only under anaesthesia. The anaesthetic protocol was composed of intramuscular injection of a combination of dexmedetomidine, methadone and ketamine and intravenous administration of propofol for induction and iso urane for maintenance. The variability of 2D-SWE values according to anaesthesia was evaluated. Median 2D-SWE values were signi cantly higher in anesthetized dogs compared to awake dogs either by considering separately the dogs in which the examination was performed both awake and under anaesthesia and by considering all dogs included. According to our study, anaesthesia helped to avoid challenges related to patient movement and respiration; however, it was a source of variability on 2D-SWE values, and this factor should be considered before performing 2D-SWE under anaesthesia

Infusione continua di detomidina durante chirurgia laparoscopica nel cavallo

RIASSUNTO L’anestesia in stazione quadrupedale è una pratica che permette l’esecuzione di diverse manualità mediche e chirurgiche nel cavallo, senza dover sottoporre il soggetto ai maggiori pericoli di un’anestesia generale. Questa tecnica anestesiologica prevede l’impiego di sedativi in associazione con una tecnica analgesica (somministrazione sistemica, anestesia loco-regionale) qualora la manualità da eseguire comporti l’insorgenza di uno stimolo dolorifico. La laparoscopia prevede l’inserimento intraddominale dei trocar e dello strumentario necessario per eseguire la tecnica. Per evitare danni agli organi da parte dello strumentario in addome, il soggetto deve mantenere una posizione adeguata e non deve effettuare movimenti bruschi. Nello studio è stato formulato un protocollo che ha previsto la sedazione del soggetto mediante la somministrazione di detomidina in associazione con buprenorfina per via endovenosa ed anestesia loco-regionale della porzione interessata dalla chirurgia mediante lidocaina. Per il mantenimento è stata attuata l’infusione endovenosa continua di detomidina con lo scopo di ottenere un livello di sedazione costante nel tempo ed adeguato alla manualità. Infatti la somministrazione di un farmaco per via endovenosa continua permette di variare più rapidamente il livello ematico di questo e, conseguentemente, di poterne modulare gli effetti. La detomidina è un farmaco che produce un accumulo nell’organismo, per cui è stato adottato un protocollo che prevede il dimezzamento il dosaggio dell’infusione ogni quindici minuti. L’impiego di questo protocollo anestesiologico ha permesso di effettuare la procedura laparoscopica senza difficoltà da parte del chirurgo. Il piano analgesico ottenuto è risultato efficace ed adeguato per lo svolgimento della manualità chirurgica. A fine intervento tutti i soggetti hanno ripreso la capacità di deambulare in breve tempo, non presentando complicazioni. SUMMARY Standing horse anesthesia is a practice that allows the execution of medical and surgical techniques, without applying to general anesthesia that is a very stressful and more dangerous event for a horse. In this kind of anesthesia, sedatives are employed in association with an analgesic technique (sistemic analgesia or loco-regional anesthesia) when the practice is supposed to be painful. The abdominal introduction of trocars and of laparoscopic tools is necessary in order to perfom a laparoscopic surgery; for this reason the patient is expected to stand motionless and it is important that it does not make roguh movements during the procedure. The wording of the anesthesia protocol for this study implied the use of detomidine for sedation in association with intravenous buprenorphine as analgesic and loco-regional anesthesia with lidocaine of the surgical area. For the maintenance, detomidine by intravenous continuous infusion was employed with the purpose to obtain a constat sedation level and adequate to the procedure. In fact the constant infusion of drugs permits to change blood concentration more rapidly and consequently it is possible to easily modulate the effects of drugs. Detomidine is a sedative that can accumulate in the organism, so the anesthestic protocol foresaw to halve the dosage every fifteen minutes. This anesthetic protocol provided a good sedation and the laparoscopic technique was performed without problems. The obtained analgesic plan resulted efficacious and adequate for the course of the surgery. At the end of the procedure all the subjects were able rapidly to walk and did not present complications

Effects of rocuronium bromide on globe position and respiratory function in isoflurane-anesthetized dogs: a comparison between three different dosages.

Objective To evaluate the effect on globe position and respiration of three dosages of intravenous rocuronium in isoflurane-anesthetized dogs. Animal studied Thirty-two dogs anesthetized for ophthalmic procedures. Procedures The dogs were divided into four groups, each of eight animals (G1-G4). G1, G2, G3 received 0.075, 0.05, 0.03 mg/kg of IV rocuronium, respectively; G4 received 0.9% NaCl IV; all the treatments were administered when an end-tidal isoflurane of 1.1–1.2% was reached. Anesthesia was obtained with dexmedetomidine (2.5 mcg/kg IV), methadone (0.1 mg/kg IV), propofol (2 mg/kg IV), and isoflurane in oxygen. Neuromuscular function was assessed with acceleromyography by stimulation of the peroneal nerve using the train-of-four (ToF) and the ToF ratio (ToFR). Monitoring of cardiovascular and respiratory functions was performed. Changes in globe position were recorded. Results All three dosages of rocuronium produced centralization of the globe. Duration was 24.3 ± 4.2, 23.4 ± 3.6, and 8.7 ± 2.8 min, for G1, G2, and G3, respectively. The control group did not show globe centralization. No significant differences were found among the four groups in cardiovascular and respiratory parameters. Minute volume and ToFR were significantly lower in G1 compared with baseline values. Conclusions All doses of rocuronium resulted in globe centralization. The higher dose provoked a transient respiratory depression and some degree of skeletal muscular blockade detectable with ToFR. No alterations in respiratory activity were present when 0.05 mg/kg was used. The 0.03 mg/kg dosage could be useful for very short ophthalmic procedures

Evaluation of echocardiographic parameters during increasing infusion rates of dobutamine in isofluorane-anesthetized horses.

Aim. to evaluate changes in echocardiographic parameters during increasing infusion rates of dobutamine in anesthetized horses and to compare our results with previous studies. Materials and Methods. Six Standardbred female horses were included. All the animals were anesthetized and infused with different rates of dobutamine. MAP, HR, and some echocardiographic measurements were recorded. Statistical analysis was applied. Results. At basal conditions, HR ranged was 32-42 bpm, MAP 39-63 mmHg. MAP increased significantly in a dose-dependent manner, while CPO, HR and CO increased significantly at the higher dosage. EF, LVDs and LVVols decreased significantly in a dose-dependent manner, while IVSs increased. Arrhythmias were diagnosed 5/6 horses. Discussion. The increase of MAP was in line with literature. The HR and MAP values at T0 are comparable to previous results obtained both in anesthetized and conscious horses, while after dobutamine infusion HR and MAP values are similar to those reported in anaesthetized horses. IVSs increased and LVDs decreased with the increment of dobutamine infusion rates. These findings suggest that dobutamine, even at low infusion rates, induces an enhancement in cardiac systolic function. The dose-dependent increase of IVSs and decrease of LVDs measurements are in line with those reported for dobutamine administered in conscious horses, but with lower values. The LVVols dose-dependent reduction is in line with others. The increment of CO might be due mainly to the enhanced HR than to the weak changes of SV. CPO increased from the 5 mcg/kg/min dosage in a dose-dependent manner, as reported by other

Comparison of two non-invasive arterial blood pressure monitoring techniques in brown bears (Ursus arctos)

Monitoring arterial blood pressure (BP), represents a more accurate evaluation of hemodynamics than heart rate alone and is essential for preventing and treating infra- and post-operative complications in wildlife chemical immobilization.The objectives of the study were to test the correlation between standard oscillometry and Korotkoffs technique in anesthetized free-ranging brown bears in Croatia and Scandinavia and to assess the blood pressure in both locations.Five bears were snared and darted with xylazine and ketamine in Croatia, and 20 bears were darted from a helicopter with medetomidine and tiletamine-zolazepam in Scandinavia. Blood pressure was simultaneously measured with both techniques every 5 minutes. Correlation between techniques, trends of BP variation, and the factors of the capture which likely influenced BP were assessed.Successful measurements of BP were achieved in 93% of all attempts with the Korotkoffs technique but in only 29% of all attempts with oscillometry. The latter method mostly provided lower values of BP compared to Korotkoffs technique in yearlings. Most bears showed a decreasing trend in systolic and mean BP over time, consistent between the two techniques. All bears were hypertensive: the auscultatory technique detected moderate to severe systolic hypertension in 25% and 84% of bears in Croatia and in Scandinavia, respectively, with significantly higher BP in subadults and adults compared to yearlings. Only Korotkoffs method resulted in a reliable and effective tool for BP assessment in brown bears. The anesthetic protocols used in the present study in association with the capture methods produced hypertension in all animals

Development of a new technology for 3-D nanostructured scaffolds with potential cardiovascular applications

Aims The in situ release and maintaining of cells to promote revascularization is a new goal of cardiovascular therapy. Endothelial progenitor cells (EPC) may contribute to the process of vascular repair. Medical devices realized according to tissue engineering are composed by a cellular component and by an artificial component, usually made of a biocompatible polymer. Scaffolds may be coated with bio-polymers like fibrin to enhance cell adhesion and growth. Aim of this study was to realize nanocomposite 3D scaffolds composed by a synthetic polymer coated with fibrin to support EPC growth and to promote in vivo angiogenesis. Methods 3D PEtU-PDMS scaffolds were studied in vitro for their biocompatibility (viability and proliferation tests; citokine release). In vivo biocompatibility was studied by intramuscular implant in a rabbit model. The scaffolds were fabricated by spray-phase inversion technique. 25U/mL thrombin was sprayed during the fabrication process. The composite scaffold was then incubated o.n. at 37?C with 18mg/mL fibrinogen. The scaffold morphology was analysed by stereo-microscopy and by scanning electron microscopy (SEM). EPC obtained from peripheral blood were cultured for 1 week on the scaffolds at the concentration of 1x106 cell/ml. Fibronectin coating was used as a control. Cell viability was assessed by confocal laser (Calcein-AM incorporation). To test in vivo angiogenesis, EPC-seeded scaffolds were subcutaneously implanted into the back of rats for 14 days. After harvesting, the scaffolds were examined histologically and immunohistochemically to evaluate inflammatory response and neovascularization. Results In vitro and in vivo biocompatibility data demonstrated absence of any citotoxic effect, immunocompatibility and a slight inflammatory reaction without any sign of encapsulation and implant rejection. Morphological analyses showed an homogeneus fibrin coating of the scaffolds, tightly bound and interconnected to the PEtU-PDMS surface. SEM showed the presence of a well organized layer of fibres in a nm scale (mean diameter ~140nm). Cell viability and phenotype were not affected when EPC were seeded on PEtU-PDMS/fibrin scaffolds. The histological observation of explanted scaffolds revealed a slightly inflammatory response and a significant increased numbers of neovessels in tissues surrounding the EPC-seeded scaffold as compared to the scaffold without cells. Conclusions Our data suggest that PEtU-PDMS/fibrin scaffold obtained with a new spray manufacturing technology can support in vitro EPC growth and promote in vivo neovascularisation. Further studies are currently under way in an ischemic hindlimb rat model

Tailored star poly (ε-caprolactone) wet-spun scaffolds for in vivo regeneration of long bone critical size defects

One of the most challenging requirements of a successful bone tissue engineering approach is the development of scaffolds specifically tailored to individual tissue defects. Besides materials chemistry, well-defined scaffold’s structural features at the micro- and macro-levels are needed for optimal bone in-growth. In this study, polymeric fibrous scaffolds with a controlled internal network of pores and modelled on the anatomical shape and dimensions of a critical size bone defect in a rabbit’s radius model were developed by employing a computer-aided wet-spinning technique. The tailored scaffolds made of star poly(ε caprolactone) or star poly(ε-caprolactone)– hydroxyapatite composite material were implanted into 20-mm segmental defects created in radial diaphysis of New Zealand white rabbits. Bone regeneration and tissue response were assessed by X-rays and histological analysis at 4, 8 and 12 weeks after surgery. No signs of macroscopic and microscopic inflammatory reactions were detected, and the developed scaffolds showed a good ability to support and promote the bone regeneration process. However, no significant differences in osteoconductivity were observed between star poly(ε-caprolactone) and star poly(ε-caprolactone)–hydroxyapatite scaffolds. Long-term study on implanted star poly(ε-caprolactone) scaffolds confirmed the presence of signs of bone regeneration and remodelling, particularly evident at 24 weeks

Studi preliminari sulla ventilazione a pressione positiva continua con maschera nel cane

RIASSUNTO La ventilazione a pressione positiva continua è una tecnica che permette di mantenere una pressione positiva all’interno delle vie aeree per tutto il ciclo respiratorio durante la ventilazione spontanea, mantenendo la pervietà delle vie aeree inferiori, in quelle condizioni che provocano il collasso degli alveoli. In questo lavoro è stata valutata la possibilità di applicare la ventilazione a pressione positiva continua con una tecnica di ventilazione non invasiva, mediante l’impiego di una valvola applicata ad una maschera per ossigenoterapia. Nello studio sono stati inseriti 5 cani di proprietà giunti al Dipartimento di Clinica Veterinaria per accertamenti diagnostici ed interventi chirurgici. Lo scopo di questo lavoro è stato quello di valutare la tollerabilità dei soggetti a questa metodica e l’efficacia rispetto ad una comune tecnica di ossigenoterapia in maschera. I cinque soggetti sono stati sottoposti ad ossigenoterapia in maschera con ventilazione spontanea e successivamente a ventilazione a pressione positiva con una pressione di 5 cm H2O. Durante la procedura sono stati monitorizzati frequenza cardiaca, frequenza respiratoria, pressione arteriosa media e temperatura. Per la valutazione dell’ossigenazione dei soggetti sono stati valutati, mediante emogas su sangue arterioso, pH, pressione parziale di ossigeno e di anidride carbonica. Riguardo alla valutazione della tollerabilità del sistema di ventilazione a pressione positiva continua in tutti i cani è stato possibile applicare la maschera raggiungendo la pressione desiderata senza avere reazioni di irrequietezza e senza l’insorgenza di dilatazione gastrica per ingestione di aria od ossigeno. Lo studio dell’efficacia ha dimostrato il raggiungimento di pressione parziale di ossigeno e di frazioni inspirate di ossigeno superiori con la tecnica con ventilazione a pressione positiva continua non invasiva, rispetto alla tecnica di ossigenoterapia classica. SUMMARY Continuous positive airways pressure is a ventilation technique used when it is necessary to sustain a positive pressure during the entire respiratory cycle in spontaneous ventilation. This method is indicated to maintain airways patency especially in condition of alveoli collapse. The object of this study was to evaluate the tolerability of a non invasive continuous positive airway pressure with a mask device in lightly sedated dogs and to compare the oxygen inspired fraction between oxygen therapy with regular mask device and between continuous positive airway pressure ventilation with mask device. Five client-owned dogs, that arrived to the Clinic in order to attempt surgical or diagnostic techniques, were enrolled in the study. Dogs received oxygen with a regular mask device with an open system and with continuous positive airway pressure ventilation at 5 cm H2O pressure ventilation. During the procedures dogs were monitored recording heart rate, respiratory rate, mean arterial pressure and temperature. For the comparison of the patients oxygenation between the two methods had been used the evaluation of blood gas analysis recording partial pressure of arterial oxygen, of carbon oxide and pH. In all dogs was possible to apply the continuous positive airway pressure ventilation with mask device without evidence of agitation, panic or gastric distension due to gas ingestion. Recorded values of partial pressure of arterial oxygen and calculated values of oxygen inspired fraction were considerably higher with non invasive continuous positive airway pressure ventilation technique compared to classic oxygen therapy method