Comparison of hemodynamic, clinicopathologic, and gastrointestinal motility effects and recovery characteristics of anesthesia with isoflurane and halothane in horses undergoing arthroscopic surgery

Objective - To compare hemodynamic, clinicopathologic, and gastrointestinal motility effects and recovery characteristics of halothane and isoflurane in horses undergoing arthroscopic surgery. Animals - 8 healthy adult horses. Procedure - Anesthesia was maintained with isoflurane or halothane (crossover study). At 6 intervals during anesthesia and surgery, cardiopulmonary variables and related derived values were recorded. Recovery from anesthesia was assessed; gastrointestinal tract motility was subjectively monitored for 72 hours after anesthesia. Horses were administered chromium, and fecal chromium concentration was used to assess intestinal transit time. Venous blood samples were collected for clinicopathologic analyses before and 2, 24, and 48 hours after anesthesia. Results - Compared with halothane-anesthetized horses, cardiac index, oxygen delivery, and heart rate were higher and systemic vascular resistance was lower in isoflurane-anesthetized horses. Mean arterial blood pressure and the dobutamine dose required to maintain blood pressure were similar for both treatments. Duration and quality of recovery from anesthesia did not differ between treatments, although the recovery periods were somewhat shorter with isoflurane. After isoflurane anesthesia, gastrointestinal motility normalized earlier and intestinal transit time of chromium was shorter than that detected after halothane anesthesia. Compared with isoflurane, halothane was associated with increases in serum aspartate transaminase and glutamate dehydrogenase activities, but there were no other important differences in clinicopathologic variables between treatments. Conclusions and clinical relevance - Compared with halothane, isoflurane appears to be associated with better hemodynamic stability during anesthesia, less hepatic and muscle damage, and more rapid return of normal intestinal motility after anesthesia in horses undergoing arthroscopic procedures.

Mecanismo de centralização: Da insuficiência placentária à adaptação circulatória fetal

The application and development of obstetric Dopplervelocimetry provide a basis for the investigation of placental insuf ciency and demonstrate the dynamic behavior of fetal circulation during hypoxia. In clinical practice, assessing hemodynamics in three vascular regions involved in pregnancy, namely the uterine, umbilical and middle cerebral arteries, has become routine. Roughly, the cerebral artery expresses the balance between uterine artery oxygen supply and umbilical artery oxygen uptake. Currently, when such balance is unfavorable, the fetal cardiac reserve is investigated by assessing the venous duct. However, determining and interpreting vascular resistance indexes is not an easy task. The starting point is to know the physiopathology of placental insuf ciency and fetal circulatory adaptation through which Doppler con rmed its role in the assessment of fetal well-being.

Azul de metileno no tratamento da síndrome vasoplégica em cirurgia cardíaca. quinze anos de perguntas, respostas, dúvidas e certezas

Objective: There is strong evidence that methylene blue (MB), an inhibitor of guanylate cyclase, is an excellent therapeutic option for vasoplegic syndrome (VS) treatment in heart surgery. The aim of this article is to review the MB's therapeutic function in the vasoplegic syndrome treatment. Methods: Fifteen years of literature review. Results: 1) Heparin and ACE inhibitors are risk factors; 2) In the recommended doses it is safe (the lethal dose is 40 mg/ kg); 3) The use of MB does not cause endothelial dysfunction; 4) The MB effect appears in cases of nitric oxide (NO) up-regulation; 5) MB is not a vasoconstrictor, by blocking of the GMPc system it releases the AMPc system, facilitating the norepinephrine vasoconstrictor effect; 6) The most used dosage is 2 mg/kg as IV bolus followed by the same continuous infusion because plasmatic concentrations strongly decays in the first 40 minutes; 7) There is a possible window of opportunity for the MB's effectiveness. Conclusions: Although there are no definitive multicentric studies, the MB used to treat heart surgery VS, at the present time, is the best, safest and cheapest option, being a Brazilian contribution for the heart surgery.

Efeitos da angiotensina II no sistema cardiovascular

Angiotensin is an important peptide of renin-angiotensin-aldosterone system. This peptide has an important function on arterial blood pressure regulation and body fluid homeostasis. However, its action on abnormal conditions causes deleterious effects on the cardiovascular system. Vascular resistance, hypertension, vascular and myocytes hipertrophy, production of free radicals and pro-inflammatory substances are some of the actions of angiotensin II that can result on cardiovascular remodeling. Angiotensinconverting enzyme (ACE) inhibitors, angiotensin receptors antagonists, antiinflammatories and antioxidants are used clinically and/or experimentally to prevent or reduce the effects of angiotensin II. The purpose of this work is to review the actions and interactions of angiotensin II on the cardiovascular system, as well as the therapeutic measures employed for the control of these effects.

Uterine and luteal hemodynamic evaluation of the non pregnant mare

Background: Studies with Doppler ultrassonography started at the end of the 90s for the determination of physiological and pathological alterations in the reproductive tract of the mare. Uterine alterations caused by inflammation, response from seminal plasma infusion, hormonal variations during estrous and diestrus, pregnancy and action of various vasoactive factors influence on the vascular perfusion detected by Doppler ultrasound. The development of efficient methods for uterine quality evaluation is of big importance for field equine reproduction veterinarians, once uterine environment is responsible for pregnancy maintenance. Review: Nowadays, the most used methods of uterine evaluation are the mode B ultrassonography, cytology, culture and biopsy. Hemodynamic evaluation of the uterus can be done by spectral data collected from large vessels, as A. uterine and its ramifications, or from subjective or objective evaluations from endometrium, miometrium and mesometrium attachment, which provide data referent to local and specific alterations of the evaluated area. Alterations in uterine vascular perfusion has been detected during estrous cycle, during pregnancy and in cases of infusion of inflammatory substances. These alterations happen because of vasoactive substances that act in the uterus during these events, however, most of these vasoactive substances are probably not even known. Also, important hemodynamic alterations in old mares, as an increase in vascular resistance, have been described. This increase might result from fibrosis of the uterus and in women it is considered to be a cause of infertility. In mares, periglandular fibrosis of the endometrium is considered to be the major diagnosable cause of embryonic and fetal loss in older mares. For the CL, ovarian artery of the mare supplies the ovary as well as the oviduct and therefore can be used for evaluation of these areas. The CL evaluation can also be done by the percentage of luteum area with colored signals as an indicator of the extent of blood flow. The percentage of the CL area with colored signals is determined subjectively by images observations in real time and/or by a freezing Power Doppler cross-section image with the maximum number of color pixels taped and the total number of color pixels is assessed by a computer analysis system. Therefore, a high correlation between plasmatic progesterone and CL vascularization also allows the CL evalution by this technique. In a first report, CL circulation reached its maximum on D5, the progesterone concentration in peripheral blood increased until D7 and in a posterior report, maximum perfusion was achieved two days after the maximum progesterone concentration (D8). Blood flow reduced between D10-D14 some days before the plasma progesterone decrease and, during the luteolytic period (D15-D17), the decline in CL blood-flow area was greater than blood flow decrease. Conclusion: Doppler ultrassonography add knowledge about uterine viability and CL functionality can be easily used by veterinarians in the field. It is a noninvasive method that provides real time results. However, because of the short time studies in this area have been done, many other answers still need to be found until normal and pathological patterns will be established.

Activation of central aα-adrenoceptors mediates salivary gland vasoconstriction

Objective: Peripheral treatment with the cholinergic agonist pilocarpine increases salivary gland blood flow and induces intense salivation that is reduced by the central injection of moxonidine (aα-adrenoceptors/ imidazoline agonist). In the present study, we investigated the effects of the intracerebroventricular (i.c.v.) injection of pilocarpine alone or combined with moxonidine also injected i.c.v. On submandibular/sublingual gland (SSG) vascular resistance. In addition, the effects of these treatments on arterial pressure, heart rate and on mesenteric and hindlimb vascular resistance were also tested. Design: Male Holtzman rats with stainless steel cannula implanted into lateral ventricle and anaesthetized with urethane + α-chloralose were used. Results: Pilocarpine (500 nmol/1 μl) injected i.c.v. Reduced SSG vascular resistance and increased arterial pressure, heart rate and mesenteric vascular resistance. Contrary to pilocarpine alone, the combination of moxonidine (20 nmol/1 μl) and pilocarpine injected i.c.v. Increased SSG vascular resistance, an effect abolished by the pre-treatment with the α2-adrenoceptor antagonist yohimbine (320 nmol/2 μl). The increase in arterial pressure, heart rate and mesenteric resistance was not modified by the combination of moxonidine and pilocarpine i.c.v. Conclusion: These results suggest that the activation of central α2- adrenoceptors may oppose to the effects of central cholinergic receptor activation in the SSG vascular resistance. © 2012 Elsevier Ltd. All rights reserved.

Analysis of follicular events in owl monkeys (Aotus azarai infulatus) using B-mode and Doppler ultrasound

Ultrasound (B-mode) was used to analyze follicular events in 12 trained female owl monkeys (Aotus azarai infulatus). The animals were examined every 48 hours for over 90days to measure and map follicular growth in both ovaries and to measure (using Doppler velocimetry) local hemodynamic changes during the peri-ovulatory stage. There were 44 follicular growth events, each with two or three follicular waves, and a mean ± SEM interval between events of 17 ± 1.13 days. There were various hemodynamic changes during follicular growth; both vascular resistance index and pulsatility index decreased during the time when the follicle diameter peaked. Thus, both B-mode and Doppler ultrasound were useful for monitoring ovarian follicular events in owl monkeys. © 2013 Elsevier Inc.

Determinação da taxa de infusão mínima de propofol e propofol associado a lidocaína em cães (Cannis familaris)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Comportamento hemodinâmico e metabólico do choque hemorrágico: estudo experimental no cão

Pós-graduação em Anestesiologia - FMB

Efeitos determinados pelo pneumoperitônio sobre a hemodinâmica e função renais de cães ventilados com volume e pressão controlados

Pós-graduação em Anestesiologia - FMB

Avaliação da técnica de dopplerfluxometria e índice de resistividade das artérias renais em cadelas com piometra

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação da função cardíaca em cães com anemia normovolência aguda experimental

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeitos da dexmedetomidina administrada em infusão intravenosa contínua, associada ou não ao butorfanol, em equinos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeitos de diferentes concentrações de isofluoretano sobre a perfusão tecidual em cães

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)