RESUMO
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.
RESUMO
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 ComplROI 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 VD/VT 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.
RESUMO
Although pain is considered the 4th vital sign and one of the most frequently observed clinical signs in domestic animals' clinical practice, its treatment is still inadequate despite significant improvement in the last few years. Acute post-operative pain has aroused great interest due to its potential risk of developing into chronic pain, and if not treated properly, it might worsen the recovery and the patient's quality of life. Cats are one of the least studied species of domestic animals regarding pain recognition and control. Some of the difficulties lie in pain assessment and perception. The consensus published in February 2016 about behavioral signs of pain in cats considered some signs to be reliable and sensitive for the assessment of pain in this species in many different clinical conditions, however it still states that more studies will be necessary in order to evaluate its clinical validity and applicability, especially considering the various pain intensities. As an attempt to quantify pain intensity in cats, several types of traditional subjective scales and others that facilitate pain assessment by combining the observation of spontaneous behavioral signals of pain and qualitative response to palpation of surgical wound are used as tools. It is necessary to use specific scales for each type of pain and for each specific animal species so to minimize the subjectivity and the partiality of the observers, reducing bias and improving efficacy, thus leading to a better patient care.(AU)
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.(AU)
