The effects of different concentrations of oxygen and nitrous oxide on blood gas parameters in pigs maintained under spontaneous or pressure-controlled ventilation, with or without positive end-expiratory pressure (PEEP), were compared. Forty-eight pigs were randomly divided into six groups, submitted to different concentrations of compressed air or N2O, associated with different fractions of inspired oxygen (FiO2). The group subject to 30% of compressed air (GA30) showed the closest proximity to the physiological range of partial pressure (PaO2) expected for the species. For oxygen saturation (SaO2), the values obtained were below the lower physiological limit in the group administered 30% N2O (GN30). Use of PEEP positively interfered in PaCO2 independent of FiO2, however, its effectiveness can be compromised when complemented by N2O-based anesthesia. For SaO2, only GN30 showed values lower than adequate for maintaining tissue oxygenation. The pH, base deficit and bicarbonate in arterial blood were influenced by FiO2 and N2O. In conclusion, the use of compressed air maintains blood gas parameters at their most stable, especially GA30 and PEEP, which seemed to positively influence the experimental groups, with some interference from FiO2 and N2O.

The goal of this study was to describe and compare B mode and elastographic characteristics of the pectineus muscle of healthy dogs with dysplastic dogs. Thirty-one dogs (62 limbs) with hip dysplasia and 17 nondysplastic dogs (34 limbs) were evaluated. The hip dysplasia score was defined according to the Fédération Cynologique Internationale. Using B mode, echotexture and echogenicity of different regions of the pectineus muscle were evaluated. By means of ARFI elastography, qualitative (elastogram) and quantitative (shear wave velocity) tissue stiffness was assessed. B mode findings demonstrated a hyperechoic and heterogeneous pattern of the pectineus tissue in dogs with hip dysplasia, with compromised muscular delimitation and loss of its normal sonographic appearance, indicating the disease (P < 0.001). In the elastogram, it was observed that dogs with hip dysplasia showed less deformable pectineus muscle, with red colors (rigid). In quantitative evaluation, the different regions evaluated presented similar shear wave velocities; in dysplastic patients, shear wave velocities were higher compared to nondysplastic animals, with values higher than 2.85 m/s being strong indicators of the disease. Values of shear wave velocity were also influenced by the grade of dysplasia and age of the patients; however, there was no correlation with the depth of the evaluated area or body weight. It was concluded that pectineus muscle in dogs with hip dysplasia presents B mode and elastographic changes when compared to normal animals, demonstrating that these techniques might aid the evaluation of diseased dogs.

This study aimed to evaluate comparatively the effects of propofol or isoflurane on hemodynamic variables in piglets that received inspired oxygen fraction (FIO2) of 0.5 under spontaneous ventilation. Therefore, sixteen piglets weighing 16±1.1kg, were randomly divided into two groups: GI (Isoflurane and FIO2 of 0.5) and GP (Propofol and FIO2 of 0.5). Heart rate (HR), systolic, diastolic and mean arterial pressure (SAP, DAP and MAP), central venous pressure (CVP), cardiac output (CO), mean pulmonary arterial pressure (mPAP) and mean capillary pulmonary pressure (mCPP) were assessed 40 minutes after anesthetic induction (T0), followed by 15 minutes intervals (from T15 to T60). The variables cardiac index (CI), stroke volume (SV), stroke index (SI), total peripheral resistance (TPR), total peripheral resistance index (TPRI), pulmonary vascular resistance (PVR), and pulmonary vascular resistance index (PVRI) were calculated. SAP and TPRI were significantly different between groups at T30 and T60 (P< 0.05) with higher GP values being recorded. There were no differences in the other variables, however, GP presented mean closer to normality on most of the analyzed variables. Therefore, we conclude that total intravenous anesthesia with propofol presented greater stability of the hemodynamic variables evaluated.

Background: Mastectomy, a procedure with high pain stimulation, is the treatment of choice for bitches with breast cancer. Tumescent anaesthesia is widely used for transoperative and postoperative analgesia in bitches submitted to mastectomy, because facilitates tissue divulsion, also contributing significantly for the rapid recovery of patients. Although, there is no consensus as to which local anesthetic to use and at what concentration it should be used. Herein was investigated which local anesthetics, lidocaine or ropivacaine, when used in tumescent solutions, could provide a more lasting analgesic effect in the postoperative period in bitches submitted to radical unilateral mastectomy.Materials, Methods & Results: Sixteen bitches were sedated with chlorpromazine (0.3 mg/kg) and meperidine (3 mg/kg) followed by anesthesia with propofol and isofluorane. Then, bitches were randomly assigned to two groups (n= 8 each): LG group, infused with 15 mL/kg of tumescence solution containing 0.1% lidocaine; and RG group, infused with 15 mL/kg of tumescence solution with 0.1% ropivacaine. The study was conducted in a double-blind fashion. Control group did not include, because the patients would be submitted to severe or unbearable pain, according to the short-form of the Glasgow pain Scale (CMPS-SF). The heart (HR) and respiratory (ƒ) rates, and systolic blood pressure (SBP) were measured in the pre-operative period and immediately after extubation (Mextub) and at 0.5 h, 1 h, 2 h, 4 h, 8 h, and 12 h after the extubation. Analgesic efficacy was assessed using the CMPS-SF and von Frey filaments. Both groups showed higher means for HR at 0.5 h (167 ± 7 in LG; 170 ± 7 in RG) than at 4 h (117 ± 7 in LG; 120 ± 7 in RG). CMPS-SF revealed higher medians (P= 0.038) at the Mextub and 12 h time points for the LG [5 (3-6) and 1 (0-2)] than for the RG [5 (2-5) and 0 (0-1)].Discussion: Pain was excluded as a possible explanation for the difference presented for HR in both groups because, moderate pain is considered when more than two cardiorespiratory parameters show an increase of at least 20% in relation to baseline values, which did not occur in this study. Indeed, most animals were walking at 0.5 h after extubation and, in many cases, this occurred before the collection of data for the postoperative period. This may have influenced the results since exercise releases catecholamines and increases HR. Moreover at 4 h after extubation, most animals were asleep. As metabolism decreases during sleep, expected that HR would also decrease and that was indeed the case. Regarding CMPS-SF, the way the patients walks was the item that most contributed to the high score found for the Mextub time point because it's impossible to be performed seconds after extubation. As the reluctance to move occurred only immediately after extubation, the values obtained at the Mextub time point are more likely to be due to an anesthetic residual effect and not to the pain stimulus itself. When the groups were compared, the median values obtained at the LG were greater than RG at the Mextub and 12 h postoperative time points.  There was no need for analgesic rescue differing from those in literature that reported the need for analgesic rescue in 50% of the animals. Those study established a CMPS-SF score of 3.3 as indicative for analgesic rescue whereas our research established a score of 7. Tumescence solutions with lidocaine or ropivacaine provide equivalent postoperative analgesia for at least 12 h.