Effects of a stepwise alveolar recruitment maneuver on lung volume distribution in dogs assessed by computed tomography

Background

Pulmonary atelectasis is a commonly occurs during anesthesia. In these cases, mechanical ventilation (MV) associated with alveolar recruitment maneuvers (ARMs) and positive end-expiratory pressure (PEEP) is indicated to reverse the condition, ensure adequate gas exchange and improve oxygenation. ARMs can trigger volutrauma, barotrauma, and atelectrauma. Therefore, computed tomography (CT) is the gold-standard method for monitoring lung aeration after ARM.

Objective

To evaluate lung volume distribution after stepwise ARMs using computed tomography (CT).

Methods

Twelve dogs weighing 24.0 ± 6.0 kg, aged 3 ± 1 years, of both sexes and different breeds, underwent orchiectomy or ovariohysterectomy. The animals were anesthetized and ventilated in volume-controlled mode. ARMs were then initiated by positive end-expiratory pressure (PEEP) titration (5, 10, 15, and 20 cmH2O). CT scans, cardiovascular parameters, and ventilatory mechanics were evaluated at all time points. Data were assessed for normality using the Shapiro-Wilk test and a two-way analysis of variance, followed by a post-hoc Bonferroni test to identify differences between time points. Statistical significance was attributed to a value of p of <0.05.

Results

CT demonstrated that the ARMs increased ventilation throughout the lung, including the dependent regions, with volumes that increased and decreased proportionally with PEEP titration. When they reached PEEP 10 and 5 cmH2O descending (d), they remained significantly higher than those in PEEP 0 cmH2O (baseline). Static compliance improved about 40% at PEEP 10d and PEEP 5d compared to baseline. There was an increase in heart rate (HR) from PEEP 15 increasing (i) (74.5%) to PEEP 10d (54.8%) compared to baseline. Mean arterial blood pressure (MABP) decreased approximately 9% from PEEP 15i to PEEP 15d compared to baseline.

Conclusion

Lung attenuation and regional and global volumes assessed by CT showed that maximum pulmonary aeration distribution followed by PEEP titration occurred at PEEP 20 cmH2O, maintaining the lungs normoaerated and without hyperaeration.

Evaluation of 3D-Printed Dog Teeth for Pre-clinical Training of Endodontic Therapy in Veterinary Dentistry

Artificial teeth in dental training have become a valuable tool for students to gain hands-on experience in a safe and controlled environment. This training method allows students to practice various dental procedures and develop their skills without putting patients at risk. Artificial teeth can be used to simulate dental conditions, allowing students to gain experience in dealing with various situations and techniques. Although previous studies in human dentistry have demonstrated the feasibility of using 3D-printed teeth for teaching endodontic procedures such as root canal therapy, similar research has yet to be conducted in the veterinary field. This study aimed to assess the feasibility of creating 3D-printed teeth from an adult dog skull and validate their use as an alternative training tool for root canal therapy in this species. For this, cone beam computed tomography images from a medium-sized dog skull were used to replicate its teeth using a digital 3D printing system. Then, artificial mandibular first molar teeth and a 24-question survey were sent to specialized veterinary dentistry practitioners in Brazil to assess their perception of the model's characteristics during endodontic treatment. In conclusion, it was feasible to create 3D-printed models of dog teeth with high accuracy for the endodontic system. Despite the differences in the properties of the two materials between natural and artificial teeth, it was possible to use the artificial tooth as a training device for conventional endodontic treatment in dogs. The reliability level for the survey was reported as good, displaying a reliability coefficient above 0.86.

Location of Trigger Points in a Group of Police Working Dogs: A Preliminary Study

This study examined the percentage and location of trigger points in police working dogs. Twelve dogs housed at a military police kennel were selected through convenience sampling. Only active dogs with no comorbidities or radiographic changes doing 6 hours of intense physical activity per day were included. After orthopedic and neurological examination, dogs were palpated for the detection of trigger points (TPs), carried out by two independent examiners, with criteria of palpations previously standardized. TPs were recorded using an anatomy reference image according to the corresponding anatomical location. The percentage of TPs was highest in the lumbar portion of the longissimus dorsi muscle (42%), followed by the latissimus dorsi, pectineus, quadriceps femoris, and sartorius (33%) muscles. Most TPs were located on the right side of the body. This study's percentage of TPs in police working dogs was higher in spinal and hind limb muscles, especially on the right side. The major criteria for identifying TPs in dogs were the pain responses to palpation and contractile local response. The findings of this study could be used to refine myofascial pain prevention to reduce early retirement due to musculoskeletal pain and draw attention to this kind of problem that can also affect dogs.

Comparison of Hemodynamic Effects of Dobutamine and Ephedrine Infusions in Isoflurane-Anesthetized Horses

The objective of this study was to compare the hemodynamic effects of dobutamine and ephedrine during the management of anesthesia-related hypotension in healthy horses. Thirteen horses underwent general anesthesia with isoflurane and were randomly divided into two different groups, one of which received a dobutamine constant rate infusion (CRI) (1 µg/kg bwt/min) and the other received an ephedrine CRI (20 µg/kg bwt/min) when hypotension (<60 mmHg) was identified, following up to 15 min after the blood pressure reached 70 mmHg. All horses were equipped with a pulmonary artery catheter and a peripheral artery catheter, and multiparameter monitoring commenced as soon as they were under mechanical ventilation. Hemodynamic parameters were recorded, while tissue perfusion markers (peripheral oxygen saturation, arterial oxygen partial pressure, arterial carbon dioxide partial pressure, arterial pH, arterial plasma bicarbonate concentration, arterial oxygen saturation, mixed venous oxygen saturation, mixed venous oxygen content, arterial oxygen content, arteriovenous oxygen difference, oxygen delivery index, oxygen consumption index, and oxygen extraction ratio), serum lactate concentration, and troponin I concentrations were analyzed before the start of infusions (T0), when the blood pressure reached 70 mmHg (T1), and 15 min after T1 (T2). The time to restore the arterial pressure was similar in both groups (p > 0.05); however, the heart rate was higher in the ephedrine group (p = 0.0098), and sinus bradyarrhythmia occurred in the dobutamine group. Furthermore, both experimental protocols increased cardiac output (p = 0.0012), cardiac index (p = 0.0013), systemic vascular resistance (p = 0.008), systemic vascular resistance index (p < 0.001), and ameliorated perfusion markers. In the dobutamine group, the pulmonary artery wedge pressure (p < 0.001) and systolic index (p = 0.003) were elevated, while the arteriovenous oxygen difference was reduced in the ephedrine group (p = 0.02). Troponin I was used as a myocardial injury indicator, and did not differ between moments or between groups (p > 0.05). We concluded that both drugs were effective and safe to treat anesthetic hypotension under the conditions of this study.

The optimal PEEP after alveolar recruitment maneuver assessed by electrical impedance tomography in healthy horses

Background

Electrical impedance tomography (EIT) has been an essential tool for assessing pulmonary ventilation in several situations, such as the alveolar recruitment maneuver (ARM) in PEEP titration to maintain the lungs open after atelectasis reversion. In the same way as in humans and dogs, in horses, this tool has been widely used to assess pulmonary aeration undergoing anesthesia, mechanical ventilation, recruitment maneuver, standing horses, or specific procedures.

Objectives

The present study aimed to evaluate the distribution of regional ventilation during ARM based on lung monitoring assessment by EIT, with a focus on better recruitment associated with less or no overdistention.

Methods

Fourteen horses of 306 ± 21 kg undergoing isoflurane anesthesia in dorsal recumbency were used. The animals were mechanically ventilated with a tidal volume of 14 ml kg^-1 and a respiratory rate of 7-9. An alveolar recruitment maneuver was instituted, increasing the PEEP by five cmH₂O every 5 min until 32 cmH₂O and decreasing it by five cmH₂O every 5 min to 7 cmH₂O. At each step of PEEP, arterial blood samples were collected for blood gas analysis, EIT images, hemodynamic, and respiratory mechanics.

Results

Associated with the CoV-DV increase, there was a significant decrease in the DSS during the ARM and a significant increase in the NSS when PEEP was applied above 12 cmH₂O compared to baseline. The Compl_ROI showed a significant increase in the dependent area and a significant decrease in the non-dependent area during ARM, and both were compared to their baseline values. The driving pressure decreased significantly during the ARM, and Cst, PaO₂, and PaO₂/FiO₂ ratio increased significantly. The V_D/V_T decreased significantly at DEPEEP17 and DEPEEP12. There was an HR increase at INPEEP27, INPEEP 32, and DEPEEP17 (p < 0.0001; p < 0.0001; and p < 0.05, respectively), those values being above the normal reference range for the species. The SAP, MAP, DAP, CI, and DO₂I significantly decreased INPEEP32 (p < 0.05).

Conclusion

The ARM by PEEP titration applied in the present study showed better ventilation distribution associated with better aeration in the dependent lung areas, with minimal overdistention between PEEP 17 and 12 cmH₂O decreasing step. Those changes were also followed by improvements in static and regional compliance associated with increased oxygenation and pulmonary ventilation. ARM promoted a transitory decrease in arterial blood pressure and depression in CI with a concomitant drop in oxygen delivery, which should be best investigated before its routine use in clinical cases.

Effects of dexmedetomidine on hemodynamic, oxygenation, microcirculation, and inflammatory markers in a porcine model of sepsis

PURPOSE

To determine whether dexmedetomidine aggravates hemodynamic, metabolic variables, inflammatory markers, and microcirculation in experimental septic shock.

METHODS

Twenty-four pigs randomized into: Sham group (n = 8), received saline; Shock group (n = 8), received an intravenous infusion of Escherichia coli O55 (3 × 109 cells/mL, 0.75 mL/kg, 1 hour); Dex-Shock group (n = 8), received bacteria and intravenous dexmedetomidine (bolus 0.5 mcg/kg followed by 0.7 mcg/kg/h). Fluid therapy and/ornorepinephrine were administered to maintain a mean arterial pressure > 65 mmHg. Hemodynamic, metabolic, oxygenation, inflammatory markers, and microcirculation were assessed at baseline, at the end of bacterial infusion, and after 60, 120, 180, and 240 minutes.

RESULTS

Compared to Shock group, Dex-Shock group presented a significantly increased oxygen extraction ratio at T180 (23.1 ± 9.7 vs. 32.5 ± 9.2%, P = 0.0220), decreased central venous pressure at T120 (11.6 ± 1 vs. 9.61 ± 1.2 mmHg, P = 0.0214), mixed-venous oxygen saturation at T180 (72.9 ± 9.6 vs. 63.5 ± 9.2%, P = 0.026), and increased plasma lactate (3.7 ± 0.5 vs. 5.5 ± 1 mmol/L, P = 0.003). Despite the Dex-Shock group having a better sublingual vessel density at T240 (12.5 ± 0.4 vs. 14.4 ± 0.3 mL/m2; P = 0.0003), sublingual blood flow was not different from that in the Shock group (2.4 ± 0.2 vs. 2.4 ± 0.1 mL/kg, P = 0.4418).

CONCLUSIONS

Dexmedetomidine did not worsen the hemodynamic, metabolic, inflammatory, or sublingual blood flow disorders resulting from septic shock. Despite inducing a better sublingual vessel density, dexmedetomidine initially and transitorily increased the mismatch between oxygen supply and demand.

Analgesic efficacy of ultrasound-guided transversus abdominis plane block in dogs undergoing ovariectomy

Background

In medicine, the transversus abdominis plane (TAP) block has been shown as an effective method of analgesia in several surgical procedures. In this context, this prospective, randomized, blinded study aimed to evaluate the analgesic efficacy of TAP block, guided by ultrasound in female dogs submitted to ovariectomy.

Methods

Therefore, 32 animals randomly assigned in two groups (n = 16) were used. Groups consisted of TAP block control (TBC) which received water injection (0.2 ml kg⁻¹ point), and TAP block bupivacaine (TBB) which received bupivacaine (0.2 ml kg⁻¹ point at 0.25%); both groups were submitted to four-point approach. Animals were pre-medicated with acepromazine (0.03 mg kg⁻¹) and meperidine (2 mg kg⁻¹) IM, propofol was used as anesthetic induction (3–5 mg kg⁻¹) IV, and isoflurane was used to maintain. To standardize groups, the animals received a continuous infusion of remifentanil (0.2μg kg⁻¹ min) and rocuronium (0.6 mg kg⁻¹) IV in the intraoperative period. Variables measured were the heart and respiratory rates, blood pressure, temperature, peripheral oxyhemoglobin saturation, exhaled carbon dioxide concentration, exhaled isoflurane concentration, serum cortisol, analgesia, and sedation. Before the pre-anesthetic medication (Baseline) and 1, 2, 4, 6, and 8 h after extubation, pain and sedation were assessed using a numeric rating scale (NRS), Glasgow composite measure pain scale (GCMPS-SF), and sedation scale. Moreover, serum cortisol was measured at different moments.

Results

The results show that in the intraoperative period, there was no significant difference between groups. After surgery, in TBC, 13 out of 16 animals required analgesic rescue, whereas, in TBB, this occurred only in one animal. Regarding the measurement of serum cortisol, the TBC group showed a significant difference when compared to the baseline time in the traction of the first ovary (p < 0.0001), 2 h (p = 0.0441), and 8 h (p = 0.0384) after extubation. In TBB, cortisol showed a significant increase only in the traction of the first ovary and 2 h after extubation (p < 0.0001).

Conclusion

The technique using ultrasound-guided TAP block in two points approach by hemiabdomen with 0.2 ml kg⁻¹ bupivacaine 0.25% was effective in providing post-operative analgesia in dogs undergoing ovariectomy.

Assessment of Regional Ventilation During Recruitment Maneuver by Electrical Impedance Tomography in Dogs

Background

During protective mechanical ventilation, electrical impedance tomography (EIT) is used to monitor alveolar recruitment maneuvers as well as the distribution of regional ventilation. This technique can infer atelectasis and lung overdistention during mechanical ventilation in anesthetized patients or in the ICU. Changes in lung tissue stretching are evaluated by monitoring the electrical impedance of lung tissue with each respiratory cycle.

Objective

This study aimed to evaluate the distribution of regional ventilation during recruitment maneuvers based on the variables obtained in pulmonary electrical impedance tomography during protective mechanical ventilation, focusing on better lung recruitment associated with less or no overdistention.

Methods

Prospective clinical study using seven adult client–owned healthy dogs, weighing 25 ± 6 kg, undergoing elective ovariohysterectomy or orchiectomy. The animals were anesthetized and ventilated in volume-controlled mode (7 ml.kg⁻¹) with stepwise PEEP increases from 0 to 20 cmH₂O in steps of 5 cmH₂O every 5 min and then a stepwise decrease. EIT, respiratory mechanics, oxygenation, and hemodynamic variables were recorded for each PEEP step.

Results

The results show that the regional compliance of the dependent lung significantly increased in the PEEP 10 cmH₂O decrease step when compared with baseline (p < 0.027), and for the nondependent lung, there was a decrease in compliance at PEEP 20 cmH₂O (p = 0.039) compared with baseline. A higher level of PEEP was associated with a significant increase in silent space of the nondependent regions from the PEEP 10 cmH₂O increase step (p = 0.048) until the PEEP 15 cmH₂O (0.019) decrease step with the highest values at PEEP 20 cmH₂0 (p = 0.016), returning to baseline values thereafter. Silent space of the dependent regions did not show any significant changes. Drive pressure decreased significantly in the PEEP 10 and 5 cmH₂O decrease steps (p = 0.032) accompanied by increased respiratory static compliance in the same PEEP step (p = 0.035 and 0.018, respectively).

Conclusions

The regional ventilation distribution assessed by EIT showed that the best PEEP value for recruitment maintenance, capable of decreasing areas of pulmonary atelectasis in dependent regions promoting less overinflation in nondependent areas, was from 10 to 5 cmH₂O decreased steps.

Sildenafil in endotoxin-induced pulmonary hypertension: an experimental study

BACKGROUND

Sepsis and septic shock still represent great challenges in critical care medicine. Sildenafil has been largely used in the treatment of pulmonary arterial hypertension, but its effects in sepsis are unknown. The aim of this study was to investigate the hypothesis that sildenafil can attenuate endotoxin-induced pulmonary hypertension in a porcine model of endotoxemia.

METHODS

Twenty pigs were randomly assigned to Control group (n = 10), which received saline solution; or to Sildenafil group (n = 10), which received sildenafil orally (100 mg). After 30 minutes, both groups were submitted to endotoxemia with intravenous bacterial lipopolysaccharide endotoxin (LPS) infusion (4 µg.kg^-1.h^-1) for 180 minutes. We evaluated hemodynamic and oxygenation functions, and also lung histology and plasma cytokine (TNFα, IL-1β, IL6, and IL10) and troponin I response.

RESULTS

Significant hemodynamic alterations were observed after 30 minutes of LPS continuous infusion, mainly in pulmonary arterial pressure (from Baseline 19 ± 2 mmHg to LPS30 52 ± 4 mmHg, p < 0.05). There was also a significant decrease in PaO₂/FiO₂ (from Baseline 411 ± 29 to LPS180 334 ± 49, p < 0.05). Pulmonary arterial pressure was significantly lower in the Sildenafil group (35 ± 4 mmHg at LPS30, p < 0.05). The Sildenafil group also presented lower values of systemic arterial pressure. Sildenafil maintained oxygenation with higher PaO₂/FiO₂ and lower oxygen extraction rate than Control group but had no effect on intrapulmonary shunt. All cytokines and troponin increased after LPS infusion in both groups similarly.

CONCLUSION

Sildenafil attenuated endotoxin-induced pulmonary hypertension preserving the correct heart function without improving lung lesions or inflammation.

Transient Pulmonary Artery Hypertension in Holstein Neonate Calves

Simple Summary

At birth, calves are challenged to maintain their vital functions that were previously supported by the placenta of cows. Failures in the neonatal adaptation process can occur during this and can cause the death of neonates. The present study aimed at the invasive hemodynamic evaluation of calves during the first 30 days of life to elucidate the changes in calves during this stage of life. In conclusion, the results of this research show a transient pulmonary arterial hypertension during the process of adapting to extrauterine life.

Abstract

The neonatal period is a challenging phase for calves, and during this phase constant adaptations are required. The aim of the present study was to evaluate the invasive hemodynamics with the Swan-Ganz catheter in neonate calves to understand adaptive changes during the first 30 days of life. A prospective and observational study was conducted with 10 Holstein calves. Assessments of the right atrial pressure (RAP), right ventricular pressure (RVP), pulmonary artery pressure (PAP), pulmonary capillary pressure (PW), cardiac output (CO), heart rate (HR), pulmonary vascular resistance (PVR), and blood gas levels were performed. The analyses of PAP, PVR, PW, HR, sO₂, and arterial blood gases differed (p < 0.05) between the evaluated periods. Our results indicated transient pulmonary artery hypertension during the process of extrauterine adaptation during the first 30 days of life. This hypertension must be considered as physiological and consequent to the neonatal adaptation process.

Myofascial Pain Syndrome, myofascial trigger points and trigger points in Veterinary Medicine

Myofascial Pain Syndrome (MPS) a is a painful condition related to myofascial trigger points (TP) in skeletal muscle. The aim of this study was to perform a literature review on the etiology, pathophysiology, diagnosis and treatment of MPS in veterinary medicine. The research sites used for this purpose were: Scientific Electronic Library, PubMed and Medline. The inclusion criteria for the papers were: must be written in English; published between 1990 and 2018; include the following keywords: myofascial pain syndrome veterinary/dog/canine/cat/feline/horse/equine, trigger points veterinary/dog/canine/cat/feline/horse/equine. Through the review, it was observed that veterinary clinical studies are scarce, and the articles found lack information such as MPS description, incidence and specific treatment techniques in dogs and horses, and no studies in cats were found.

Goniometric Assessment in French Bulldogs

Goniometry is a low-cost, user-friendly and widely available technique used by different veterinary medicine professionals to estimate joint range of motion (ROM). Studies providing breed-specific reference ranges for goniometric measurements are scarce and there is a lack of information regarding joint angles in French Bulldogs. This prospective study set out to determine normal ROM for the carpus, elbow, shoulder, tarsus, stifle and hip joints in healthy, adult French Bulldogs using goniometry. We hypothesized ROM would be similar in this and other dog breeds. Twenty dogs met the inclusion criteria. Sample size was calculated using power analysis based on previous studies. Goniometric measurements were made by a single examiner. Limbs were measured in random order and three measurements made per joint. Dogs were not sedated. Joint angles measured in French Bulldogs in this study were similar to those reported in Labrador Retrievers (shoulder, carpal, and tarsal flexion), Rottweilers (shoulder, carpus, and hip flexion), and Dachshunds (hip, stifle, and tarsal flexion). Similar flexion angles and ROM were detected in right and left limb joints. Findings of this study suggest similar ROM in French Bulldogs and other dog breeds. Lack of radiographic assessment and the fact that goniometric measurements were made by a single examiner were the major limitations of this study.

Recognition and behavioral assessment of acute pain in cats: literature review

Embora a dor seja considerada o quarto sinal vital e uma das manifestações mais comumente encontradas na prática médica veterinária dos animais domésticos, seu tratamento ainda é inadequado. A dor aguda pós-operatória tem suscitado grande interesse por seu potencial risco de cronificação caso não adequadamente tratada, podendo piorar a recuperação e a qualidade de vida do paciente. O gato é uma das espécies domésticas menos estudadas no que diz respeito ao reconhecimento e controle da dor, e algumas das dificuldades residem na avaliação e na percepção da dor. O consenso sobre os sinais comportamentais da dor nesta espécie publicado em fevereiro de 2016 considerou alguns sinais como confiáveis e sensíveis para a avaliação da dor em gatos, em toda uma gama de diferentes condições clínicas, porém afirma a necessidade da realização de estudos que analisem a sua validade e aplicabilidade clínica, especialmente em relação a diferentes intensidades de dor. Na tentativa de se quantificar a dor são utilizados vários tipos de escalas subjetivas tradicionais e outras que facilitam a avaliação da efetividade da analgesia, a partir da observação de sinais comportamentais espontâneos indicativos de dor, combinada a uma resposta qualitativa à palpação da ferida cirúrgica. Faz-se necessária a utilização de escalas específicas para o tipo de dor (aguda ou crônica) e para a espécie, de modo a minimizar a subjetividade e a parcialidade dos observadores e possibilitando uma melhor assistência ao paciente.

Small Animal Massage Therapy: A Brief Review and Relevant Observations

Massage therapy is becoming increasingly popular in human and animal physiotherapy and rehabilitation. Wider application of the technique led to research efforts aimed at providing scientific support to anecdotal beneficial effects, particularly pain relief. Recent studies have shown that massage therapy alters dopamine and serotonin levels, decreases noradrenaline levels, and modulates the immune system. Psychological effects such as reduction of stress and anxiety, with improvement of depressive patients, have been reported in humans. This article set out to review the major aspects of massage therapy based on recent publications on the topic, and to extrapolate concepts and practical aspects described in human physiotherapy to the veterinary patient, particularly the applicability of different techniques in Small Animal Medicine. Indications of massage therapy in small animals include pain relief, orthopedic rehabilitation, Canine Sports Medicine, intensive care, and management of nonspecific edema. Techniques described in this article were originally intended for use in humans and scientific data supporting anecdotal, beneficial effects in domestic animals are still lacking; this fruitful area for research is therefore open to veterinary professionals.

Sciatic and femoral nerve blockade using bupivacaine alone, or in combination with dexmedetomidine or buprenorphine in cats

The aim of this study was to determine the onset and offset of antinociception after sciatic (ScN) and femoral (FN) nerve blocks. Six healthy adult cats (4.8±1.3years; 4.3±0.4 kg) were included in a randomised, crossover, blinded and controlled study. Following sedation with dexmedetomidine (25 µg/kg, intramuscular), each ScN and FN injection was performed using 0.1 ml/kg of saline (CONTROL), bupivacaine (0.46 per cent, 0.46 mg/kg; BUPI), bupivacaine and dexmedetomidine (1 µg/kg; BUPI-DEX) or bupivacaine and buprenorphine (2.5 µg/kg; BUPI-BUPRE). Atipamezole (250 µg/kg) was administered after injections. Paw withdrawal thresholds (PWT) and motor blockade were evaluated before sedation and up to 24 hours. The PWT were significantly increased at half an hour in CONTROL, from two to four hours in BUPI and BUPI-DEX when compared with baseline. Motor blockade was observed between one and three hours in treatments using bupivacaine. Ability to walk was significantly impaired in BUPI at half an hour to two hours, BUPI-DEX at one to two hours and BUPI-BUPRE at two hours. Antinociception was observed in BUPI between one and eight hours, and in BUPI-DEX and BUPI-BUPRE between one and four hours. This study could not demonstrate a benefit of administering bupivacaine with dexmedetomidine or buprenorphine in cats. Results in BUPI-DEX may have been biased by the administration of atipamezole.

Effect of hypertonic saline treatment on the inflammatory response after hydrochloric acid-induced lung injury in pigs

OBJECTIVES

Hypertonic saline has been proposed to modulate the inflammatory cascade in certain experimental conditions, including pulmonary inflammation caused by inhaled gastric contents. The present study aimed to assess the potential anti-inflammatory effects of administering a single intravenous dose of 7.5% hypertonic saline in an experimental model of acute lung injury induced by hydrochloric acid.

METHODS

Thirty-two pigs were anesthetized and randomly allocated into the following four groups: Sham, which received anesthesia and were observed; HS, which received intravenous 7.5% hypertonic saline solution (4 ml/kg); acute lung injury, which were subjected to acute lung injury with intratracheal hydrochloric acid; and acute lung injury + hypertonic saline, which were subjected to acute lung injury with hydrochloric acid and treated with hypertonic saline. Hemodynamic and ventilatory parameters were recorded over four hours. Subsequently, bronchoalveolar lavage samples were collected at the end of the observation period to measure cytokine levels using an oxidative burst analysis, and lung tissue was collected for a histological analysis.

RESULTS

Hydrochloric acid instillation caused marked changes in respiratory mechanics as well as blood gas and lung parenchyma parameters. Despite the absence of a significant difference between the acute lung injury and acute lung injury + hypertonic saline groups, the acute lung injury animals presented higher neutrophil and tumor necrosis factor alpha (TNF-α), interleukin (IL)-6 and IL-8 levels in the bronchoalveolar lavage analysis. The histopathological analysis revealed pulmonary edema, congestion and alveolar collapse in both groups; however, the differences between groups were not significant. Despite the lower cytokine and neutrophil levels observed in the acute lung injury + hypertonic saline group, significant differences were not observed among the treated and non-treated groups.

CONCLUSIONS

Hypertonic saline infusion after intratracheal hydrochloric acid instillation does not have an effect on inflammatory biomarkers or respiratory gas exchange.

A comparison of pre and post-operative vedaprofen with ketoprofen for pain control in dogs

Background

This prospective randomized blinded clinical study aimed to investigate the potential of vedaprofen for preventive analgesia, comparing its analgesic effects with ketoprofen administered post-operatively in dogs undergoing maxillectomy or mandibulectomy.

Results

Pain control was effective and rescue analgesia was not necessary in any group. Pain scores were not significantly different between groups. The respiratory rate and rectal temperature were decreased in all groups at extubation until 6 hours post-extubation compared to baseline. Cortisol and epinephrine levels were increased only at 0.5 hours after extubation in all groups compared to baseline.

Conclusions

Vedaprofen did not present any preventive analgesic effect. Pre- and postoperative vedaprofen were as effective as ketoprofen for postoperative pain control.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-015-0338-4) contains supplementary material, which is available to authorized users.

The effect of premedication with ketamine, alone or with diazepam, on anaesthesia with sevoflurane in parrots (Amazona aestiva)

BACKGROUND

Premedication is rarely used in avian species. The aim of this study was to evaluate the effect of premedication on the quality of sevoflurane induction and anaesthesia in parrots. We hypothesised that premedication would facilitate handling and decrease the minimum anaesthetic dose (MAD). Thirty-six adult parrots were randomly distributed in three groups: group S (n = 12) was premedicated with NaCl 0.9%; group KS (n = 12) was premedicated with 10 mg.kg-1 ketamine; and group KDS (n = 12) was premedicated with 10 mg.kg-1 ketamine and 0.5 mg.kg-1 diazepam, delivered intramuscularly. After induction using 4.5% sevoflurane introduced through a facemask, the MAD was determined for each animal. The heart rate (HR), respiratory rate (RR), systolic arterial blood pressure (SAP), and cloacal temperature (CT) were recorded before premedication (T0), 15 minutes after premedication (T1), and after MAD determination (T2). Arterial blood gas analyses were performed at T0 and T2. The quality of anaesthesia was evaluated using subjective scales based on animal behaviour and handling during induction, maintenance, and recovery. Statistical analyses were performed using analysis of variance or Kruskal-Wallis tests followed by Tukey's or Dunn's tests.

RESULTS

The minimal anaesthetic doses obtained were 2.4 ± 0.37%, 1.7 ± 0.39%, and 1.3 ± 0.32% for groups S, KS, and KDS, respectively. There were no differences in HR, RR, or CT among groups, but SAP was significantly lower in group S. Sedation was observed in both the premedicated S-KS and S-KDS groups. There were no differences in the quality of intubation and recovery from anaesthesia among the three groups, although the induction time was significantly shorter in the pre-medicated groups, and the KS group showed less muscle relaxation.

CONCLUSIONS

Ketamine alone or the ketamine/diazepam combination decreased the MAD of sevoflurane in parrots (Amazona aestiva). Ketamine alone or in combination with diazepam promoted a good quality of sedation, which improved handling and reduced the stress of the birds. All protocols provided safe anaesthesia in this avian species.

Use of pulse pressure variation to estimate changes in preload during experimental acute normovolemic hemodilution

BACKGROUND

Acute normovolemic hemodilution (ANH) is an alternative to blood transfusion in surgeries involving blood loss. This experimental study was designed to evaluate whether pulse pressure variation (PPV) would be an adequate tool for monitoring changes in preload during ANH, as assessed by transesophageal echocardiography.

METHODS

Twenty-one anesthetized and mechanically ventilated pigs were randomized into three groups: CTL (control), HES (hemodilution with 6% hydroxyethyl starch at a 1:1 ratio) or NS (hemodilution with saline 0.9% at a 3:1 ratio). Hemodilution was performed in animals of groups NS and HES in two stages, with target hematocrits 22% and 15%, achieved at 30-minute intervals. After two hours, 50% of the blood volume withdrawn was transfused and animals were monitored for another hour. Statistical analysis was based on ANOVA for repeated measures followed by multiple comparison test (P<0.05). Pearson's correlations were performed between changes in left ventricular end-diastolic volume (LVEDV) and PPV, central venous pressure (CVP) and pulmonary artery occlusion pressure (PAOP).

RESULTS

Group NS received a significantly greater amount of fluids during ANH (NS, 900 ± 168 mL vs. HES, 200 ± 50 mL, P<0.05) and presented greater urine output (NS, 2643 ± 1097 mL vs. HES, 641 ± 338 mL, P<0.001). Significant decreases in LVEDV were observed in group NS from completion of ANH until transfusion. In group HES, only increases in LVEDV were observed, at the end of ANH and at transfusion. Such changes in LVEDV (∆LVEDV) were better reflected by changes in PPV (∆PPV, R=-0.62) than changes in CVP (∆CVP, R=0.32) or in PAOP (∆PAOP, R=0.42, respectively).

CONCLUSION

Changes in preload during ANH were detected by changes in PPV. ∆PPV was superior to ∆PAOP and ∆CVP to this end.

Avaliação do tratamento cirúrgico da hérnia perineal em cães com o reforço de membrana de pericárdio equino preservado em glicerina a 98%

A utilização de membrana biológica constitui-se método alternativo na reparação de hérnia perineal, e avaliar sua eficiência como reforço após a herniorrafia pela técnica de elevação do músculo obturador interno consiste no objetivo deste trabalho. Para tanto, utilizaram-se dez cães atendidos no Serviço de Cirurgia de Pequenos Animais do Hospital Veterinário da FMVZ/USP. Os animais foram distribuídos em dois grupos, GI e GII, com cinco representantes em cada um. A hérnia perineal foi corrigida pela técnica de elevação do músculo obturador interno em ambos os grupos, sendo que o grupo GII ganhou reforço no diafragma pélvico com enxerto de retalho de pericárdio equino Puro Sangue Inglês, conservado em glicerina a 98%. Os animais foram avaliados por até 90 dias de pós-operatório, mediante análises clínica, ultrassonográfica e radiográfica da região perineal. Os resultados obtidos demonstraram que houve reforço no local da herniorrafia ao se fixar o pericárdio de equino conservado em glicerina a 98%, diminuindo a ocorrência de deiscência de pontos e ruptura do diafragma operado.

A comparison between pulse pressure variation and right end diastolic volume index as guides to resuscitation in a model of hemorrhagic shock in pigs

BACKGROUND

Different hemodynamic parameters including static indicators of cardiac preload as right ventricular end-diastolic volume index (RVEDVI) and dynamic parameters as pulse pressure variation (PPV) have been used in the decision-making process regarding volume expansion in critically ill patients. The objective of this study was to compare fluid resuscitation guided by either PPV or RVEDVI after experimentally induced hemorrhagic shock.

METHODS

Twenty-six anesthetized and mechanically ventilated pigs were allocated into control (group I), PPV (group II), or RVEDVI (group III) group. Hemorrhagic shock was induced by blood withdrawal to target mean arterial pressure of 40 mm Hg, maintained for 60 minutes. Parameters were measured at baseline, time of shock, 60 minutes after shock, immediately after resuscitation with hydroxyethyl starch 6% (130/0.4), 1 hour and 2 hours thereafter. The endpoint of fluid resuscitation was determined as the baseline values of PPV and RVEDVI. Statistical analysis of data was based on analysis of variance for repeated measures followed by the Bonferroni test (p < 0.05).

RESULTS

Volume and time to resuscitation were higher in group III than in group II (group III = 1,305 +/- 331 mL and group II = 965 +/- 245 mL, p < 0.05; and group III = 24.8 +/- 4.7 minutes and group II = 8.8 +/- 1.3 minutes, p < 0.05, respectively). All static and dynamic parameters and biomarkers of tissue oxygenation were affected by hemorrhagic shock and nearly all parameters were restored after resuscitation in both groups.

CONCLUSION

In the proposed model of hemorrhagic shock, resuscitation to the established endpoints was achieved within a smaller amount of time and with less volume when guided by PPV than when guided by pulmonary artery catheter-derived RVEDVI.

Hemodynamic effects of PEEP in a porcine model of HCl-induced mild acute lung injury

BACKGROUND

Positive end-expiratory pressure (PEEP) and sustained inspiratory insufflations (SI) during acute lung injury (ALI) are suggested to improve oxygenation and respiratory mechanics. We aimed to investigate the hemodynamic effects of PEEP with and without alveolar recruiting maneuver in a mild ALI model induced by inhalation of hydrochloric acid.

METHODS

Thirty-two pigs were randomly allocated into four groups (Control-PEEP, Control-SI, ALI-PEEP and ALI-SI). ALI was induced by intratracheal instillation of hydrochloric acid. PEEP values were progressively increased and decreased from 5, 10, 15 and 20 cmH2O in all groups. Three SIs maneuvers of 30 cmH2O for 20 s were applied to the assignable groups between each PEEP level. Transesophageal echocardiography (TEE), global hemodynamics, oxygenation indexes and gastric tonometry were measured 5 min after the maneuvers had been concluded and at each established value of PEEP (5, 10, 15 and 20 cmH2O).

RESULTS

The cardiac index, ejection fraction and end-diastolic volume of right ventricle were significantly (P < 0.001) decreased with PEEP in both Control and ALI groups. Left ventricle echocardiography showed a significant decrease in end-diastolic volume at 20 cmH2O of PEEP (P < 0.001). SIs did not exert any significant hemodynamic effects either early (after 5 min) or late (after 3 h).

CONCLUSIONS

In a mild ALI model induced by inhalation of hydrochloric acid, significant hemodynamic impairment characterized by cardiac function deterioration occurred during PEEP increment, but SI, probably due to low applied values (30 cmH2O), did not exert further negative hemodynamic effects. PEEP should be used cautiously in ALI caused by acid gastric content inhalation.

Hydroxyethyl starch is superior to lactated Ringer as a replacement fluid in a pig model of acute normovolaemic haemodilution

BACKGROUND

Tissue tolerance to oxygen privation during acute normovolaemic haemodilution with different fluids remains unclear. We tested the hypothesis that hydroxyethyl starch (HES) is superior to lactated Ringer's solution in pigs for preserving tissue perfusion during acute normovolaemic haemodilution.

METHODS

Twenty-four animals were randomized into control, lactated Ringer's solution and HES groups. All groups, except the control, underwent acute normovolaemic haemodilution. Haemodynamics, oxygen parameter indices, global anaerobic metabolic markers, echocardiographic parameters, gastric tonometry and serum osmolarity were monitored at baseline, immediately after (0 min) and 60 and 120 min after the end of haemodilution. Myocardial, liver, stomach and intestine samples were collected for further evaluation.

RESULTS

Cardiac and oxygen parameter index responses to acute normovolaemic haemodilution were comparable. However, the increment in cardiac index, stroke volume index, and left ventricular stroke work index were more sustained in the starch group. In the lactated Ringer's group, gastric pH decreased significantly and was accompanied by a significant increase in lactate. Myocardial ultrastructure was better preserved in the starch group. The other tissue samples presented no change.

CONCLUSIONS

In this model of ANH, the starch group had a superior haemodynamic response. Minor loss of myocardial cellular integrity and preserved gastric pHi reinforce these findings.

Gonadectomia em gatas impúberes: técnica anestésica

O objetivo deste estudo foi descrever e avaliar um protocolo anestésico em filhotes de gatas submetidas a gonadectomia. Foram estudadas 40 fêmeas, com 2 a 4 meses de idade, sem raça definida, encaminhadas para ovariohisterectomia. O protocolo anestésico empregado consistiu de pré-medicação com acepromazina e meperidina e a indução e manutenção anestésicas realizadas com tiletamina-zolazepam. Foram avaliadas freqüências cardíaca e respiratória, saturação periférica da oxihemoglobina, temperatura corpórea, qualidade do relaxamento de coto uterino e pedículos ovarianos, tempo cirúrgico e de recuperação anestésica, bem como qualidade da recuperação anestésica e outros efeitos adversos. Houve redução da freqüência respiratória e manutenção da cardíaca no período trans-operatório. Apenas dois animais necessitaram de suplementação com oxigênio e a qualidade da recuperação foi satisfatoriamente tranqüila. O relaxamento dos pedículos ovarianos e coto uterino foi adequado e não foram observados demais efeitos adversos. Diante dos resultados obtidos pode-se concluir que a técnica anestésica empregada foi segura e efetiva nos animais estudados.

Efeitos cardiovasculares e pulmonares da associação da romifidina e butorfanol em eqüinos

Os efeitos da associação de romifidina (60 µg/kg) com butorfanol (40 µg/kg) i.v. foram avaliados em oito eqüinos. Os parâmetros foram avaliados antes da sedação e 10 (T0), 15 (T2), 30 (T3), 40 (T4) e 65 (T5) minutos após. Os valores da freqüência cardíaca, débito cardíaco e índice cardíaco apresentaram redução significativa após a sedação. Um aumento significativo após a sedação foi observado nos valores da pressão da artéria pulmonar, pressão de oclusão de artéria pulmonar, pressão venosa central e índice de resistência vascular sistêmica. Os valores da pressão arterial sistólica, média e diastólica, índice sistólico e resistência vascular pulmonar não apresentaram alterações significativas. Houve redução significativa nos valores da freqüência respiratória, saturação de oxigênio no sangue venoso misto, conteúdo de oxigênio no sangue venoso misto e índice de oferta de oxigênio após a sedação. Os valores da pressão parcial de oxigênio, saturação arterial de oxigênio, pressão parcial de oxigênio no sangue venoso misto, conteúdo arterial de oxigênio no sangue arterial, diferença arteriovenosa de oxigênio, índice de consumo de oxigênio, taxa de extração de oxigênio, pH e bicarbonato plasmático no sangue arterial não apresentaram alterações significativas. Um aumento significante da pressão parcial de dióxido de carbono ocorreu aos 40 minutos após a sedação. A combinação de romifidina e butorfanol levou a depressão cardiovascular semelhante a relatada com o uso de romifidina isoladamente.

Estudo retrospectivo dos casos de enterolitíase e corpo estranho em intestino grosso de eqüinos, no período de janeiro de 1993 a janeiro de 2003

No período de janeiro de 1993 a janeiro de 2003, foram realizados 195 procedimentos cirúrgicos de abdômen agudo em eqüinos, no Serviço de Cirurgia de Grandes Animais do Hospital Veterinário da Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo. Dentre eles, foram diagnosticados 30 casos de enterolitíase e sete casos de corpo estranho, localizados em intestino grosso. Das 37 laparotomias, 35 foram realizadas em decúbito dorsal com acesso pela linha média e duas em estação com acesso pelo flanco. Os animais apresentaram idade variando de um a dezoito anos com média de oito anos, sendo 25 machos e 13 fêmeas. As formações e corpos estranhos apresentaram a seguinte localização: 13 (35,14%) em cólon maior, 19 (51,35%) em cólon menor, 03 (8,10%) em cólon transverso e 02 (5,41%) em cólon transverso e menor. Em relação à evolução, 23 (62,16%) receberam alta e 14 (37,84%) evoluíram para óbito (6) ou foram submetidos à eutanásia (8). Seis procedimentos de eutanásia foram realizados no período trans-operatório e dois no período pós-operatório. Dentre os animais que apresentaram evolução satisfatória, destacam-se um caso em que foram retirados sete enterólitos e outro em que a ponta de um prego que era o núcleo do enterólito se mantinha proeminente e em contato com a mucosa intestinal. Comparativamente às demais afecções do intestino grosso dos eqüinos e pela análise dos resultados obtidos neste estudo, conclui-se que os processos obstrutivos causados por enterólitos ou corpos estranhos apresentam prognóstico favorável.

Estudo comparativo entre sutura mecânica e manual em brônquio após pneumonectomia esquerda em cães (Canis familiaris): uma avaliação anatomopatológica

O objetivo deste estudo foi realizar um estudo experimental comparando-se sob o ponto de vista anatomopatológico as suturas manual e mecânica em brônquio principal após pneumonectomia esquerda em cães. Foram utilizados 18 cães, sadios, machos e fêmeas, adultos, sem raça definida, pesando entre 9 e 27,5 kg. Foram separados em 2 grupos de 9 cães, de acordo com o tipo de sutura empregada: Grupo A - sutura manual com fio polipropileno 5-0; Grupo B - sutura mecânica com grampeador mecânico modelo TL-30. Cada grupo foi subdividido em 3 subgrupos de 3 animais, sendo estabelecido estudo temporal aos 7, 15 e 36 dias de pós-operatório, onde foi realizada avaliação anatomopatológica da cicatrização das suturas manual e mecânica. Na avaliação histopatológica foram avaliados, qualitativamente e semi-quantitativamente, intensidade da inflamação, fibrose, vasos neoformados e presença ou não de tecido de granulação, granuloma tipo corpo estranho e necrose. Os resultados encontrados foram analisados estatisticamente. Com relação à análise histopatológica, ocorreu a formação de granuloma tipo corpo estranho no coto brônquico esquerdo em 88,9% dos cães submetidos à sutura manual e em nenhum dos cães submetidos à sutura mecânica. Houve, ainda, diferença estatística significativa nos cães dos Grupos A e B em relação à intensidade da inflamação, sendo de maior intensidade nos cães submetidos à sutura manual. Concluiu-se que os 2 tipos de sutura promoveram cicatrização adequada do coto brônquico principal esquerdo, embora tenha ocorrido maior intensidade de inflamação e maior ocorrência de granuloma tipo corpo estranho nos cães submetidos à sutura manual.

EVIDENCE FOR MYOCARDIAL DEFECTS UNDER EXTREME ACUTE NORMOVOLEMIC HEMODILUTION WITH HYDROXYETHYL STARCH AND LACTATED RINGER'S SOLUTION

Acute normovolemic hemodilution (ANH) has been proposed to avoid the risks of allogenic transfusion. In reference to its cellular effects, ANH reports in the literature are scarce. Using electron microscopy (EM), we evaluated the effects of ANH on cardiac function and myocardial structure. Twenty-five dogs were prospectively randomized to a control group (n = 5) or to undergo ANH with 6% hydroxyethyl starch (HES; n = 10) or lactated Ringer's solution (LR; n = 10) administered, respectively, at a ratio of 1:1 or 1:3 to the volume of blood removed. Animals were gradually hemodiluted to a hematocrit of 10%, which was accomplished in 80 min. Pulmonary artery catheter and echocardiography were used to evaluate cardiac function. Myocardial samples were taken after the last time point for electron microscopy analysis. Data were obtained during five different stages of ANH, with a mean 20-min interval between each time point. Cardiac index increased significantly in both groups during ANH. A significant decrease in oxygen delivery and oxygen consumption, as well as an increase in oxygen extraction was verified in the LR group. Echocardiography demonstrated a decline in systolic function in the LR group at the end of the experiment. Electron microscopy analysis of the myocardium revealed slight lesions in cardiac cells in the HES group, and moderate-to-significant lesions in the LR group. In this animal species, ANH with HES resulted in better preservation of cardiac function, which was demonstrated by maintenance of systolic function and oxygenation parameters. Minor loss of cellular integrity with HES, in the presence of very low levels of hemoglobin, reinforces these findings.

Avaliação da eficácia do tramadol, um analgésico opióide atípico, no controle da dor pós-operatória em cães submetidos a procedimentos cirúrgicos ortopédicos

Comparou-se a qualidade da analgesia pós-operatória após administração preemptiva de tramadol (2 mg/kg/grupo 1) e flunixin meglumine (1,1 mg/kg/grupo 2) em 30 cães submetidos a procedimentos cirúrgicos ortopédicos. Os animais tratados com tramadol apresentaram maior grau de analgesia comparado ao grupo do flunixim meglumine. A qualidade do retorno anestésico dos animais tratados com tramadol foi superior, livre de excitação e desconforto e com grau de sedação superior ao grupo do flunixin meglumine. Não foram observadas alterações cardiovasculares e respiratórias durante a anestesia. Podemos concluir que o tramadol pode ser utilizado como analgésico preemptivo em cães submetidos a procedimentos cirúrgicos ortopédicos, já que o retorno anestésico apresentou adequada analgesia, livre de desconforto e excitação.

Diagnóstico e correção cirúrgica do defeito septal atrial pela técnica de parada circulatória

O presente caso trata-se do relato de correção cirúrgica do defeito septal atrial em cão. Este caso objetivou a demonstração dos métodos diagnósticos utilizados assim como o reparo cirúrgico utilizando-se da técnica de parada circulatória e posterior fechamento do defeito através de sutura. Tal técnica mostrou-se altamente exeqüível em medicina veterinária já que não utiliza circulação extra-corpórea.

A Comparative Evaluation of Inhaled Halothane, Isoflurane, and Sevoflurane During Acute Normovolemic Hemodilution in Dogs

The hemodynamic response to acute normovolemic hemodilution (ANH) can be affected by the anesthetics used. We randomized 18 mongrel dogs to undergo ANH with 3 different inhaled anesthetics: halothane, isoflurane, or sevoflurane. Hemodynamics, oxygen transport, and gastric pH were measured before blood withdrawal, at the end of hemodilution, and 30 and 60 min after the end of hemodilution. The baseline measurements of all hemodynamic variables were similar among groups, with the exception of heart rate, which was more rapid in the sevoflurane group. Thirty minutes after hemodilution, the cardiac index increased 88%, 86%, and 157% in the halothane, isoflurane, and sevoflurane groups, respectively, whereas arterial-venous oxygen differences and oxygen consumption were larger in the halothane group compared with the isoflurane and sevoflurane groups. Gastric pH obtained by tonometry did not change and was not different among groups. Because the hemodynamic response to ANH was not blunted, all three anesthetics may be safely used for the maintenance of anesthesia.

Use of the scrotum as a transposition flap for closure of surgical wounds in three dogs

OBJECTIVE

To describe use of the scrotum as a pedicle flap to cover defects created by tumor excision in the perineum or caudal and medial aspect of the thigh.

STUDY DESIGN

Clinical study.

ANIMALS

Three dogs.

METHODS

After tumor excision and prescrotal castration, an incision was made around the base of the scrotum, leaving a pedicle on the side opposite the skin defect. After removal of the tunica dartos and abdominal fascia, the scrotal skin was stretched and shaped to the defect, then sutured in position with a simple interrupted pattern. Bandages that were changed every 48 hours compressed the flaps, and healing was observed until sutures were removed.

RESULTS

Two dogs had first intention healing in 15 days, whereas 1 dog developed necrosis of 10% of the flap, and this area healed by second intention.

CONCLUSION

In male dogs, the scrotal skin can be used as a pedicle flap for reconstructive surgery of wounds in the perineum and the proximomedial and caudal aspect of the thigh.

CLINICAL RELEVANCE

The perineal region remains a surgical challenge because of the lack of the available skin for reconstruction of surgical wounds. The scrotal skin should be considered for use as a transposition flap to cover skin defects in this region.