Aline Magalhães Ambrósio

Effects of Positive End-expiratory Pressure Titration and Recruitment Maneuver on Lung Inflammation and Hyperinflation in Experimental Acid Aspiration–induced Lung Injury

Background:In acute lung injury positive end-expiratory pressure (PEEP) and recruitment maneuver are proposed to optimize arterial oxygenation. The aim of the study was to evaluate the impact of such a strategy on lung histological inflammation and hyperinflation in pigs with acid aspiration–induced lung injury. Methods:Forty-seven pigs were randomly allocated in seven groups: (1) controls spontaneously breathing; (2) without lung injury, PEEP 5 cm H2O; (3) without lung injury, PEEP titration; (4) without lung injury, PEEP titration + recruitment maneuver; (5) with lung injury, PEEP 5 cm H2O; (6) with lung injury, PEEP titration; and (7) with lung injury, PEEP titration + recruitment maneuver. Acute lung injury was induced by intratracheal instillation of hydrochloric acid. PEEP titration was performed by incremental and decremental PEEP from 5 to 20 cm H2O for optimizing arterial oxygenation. Three recruitment maneuvers (pressure of 40 cm H2O maintained for 20 s) were applied to the assigned groups at each PEEP level. Proportion of lung inflammation, hemorrhage, edema, and alveolar wall disruption were recorded on each histological field. Mean alveolar area was measured in the aerated lung regions. Results:Acid aspiration increased mean alveolar area and produced alveolar wall disruption, lung edema, alveolar hemorrhage, and lung inflammation. PEEP titration significantly improved arterial oxygenation but simultaneously increased lung inflammation in juxta-diaphragmatic lung regions. Recruitment maneuver during PEEP titration did not induce additional increase in lung inflammation and alveolar hyperinflation. Conclusion:In a porcine model of acid aspiration–induced lung injury, PEEP titration aimed at optimizing arterial oxygenation, substantially increased lung inflammation. Recruitment maneuvers further improved arterial oxygenation without additional effects on inflammation and hyperinflation.

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.

Effect of postoperative xylazine administration on cardiopulmonary function and recovery quality after isoflurane anesthesia in horses.

OBJECTIVE To evaluate equine cardiopulmonary function and recovery quality after administration of 0.25 or 0.50 mg/kg xylazine intravenously (IV) during recovery. STUDY DESIGN Randomized, blinded, prospective, clinical study. ANIMALS Horses (n = 20). METHODS During recovery after 3 hours of isoflurane anesthesia for arthroscopic surgery, horses were administered either 0.25 mg/kg (G25, n = 10) or 0.50 mg/kg (G50, n = 10) xylazine intravenously. Vital signs and arterial blood samples were obtained during recovery before sedation (baseline), 5, 10, 20, 30, and 45 minutes after xylazine and 30 minutes after standing. The quality of recovery scores ranged from 10 to 72 (10 = best, 72 = worst). RESULTS G25 horses recovered faster (mean ± SD, 33 ± 5 min) than G50 horses (50 ± 7 min, P < .0001). Mean maximal decrease in arterial oxygen tension was 55 ± 11 mmHg in G25 (at 10 minutes; P < .05) and 54 ± 7 mmHg in G50 (at 20 minutes; P < .01). G25 group had a total recovery score (23 [range 18-29]) and number of attempts to stand (4 ± 2) greater than the G50 group (18 [10-23] and 1 ± 1, respectively; P < .001). CONCLUSIONS Both doses of xylazine promoted a moderate and transient hypoxemia during recovery; however, the 0.5 mg/kg dose produced a longer and improved quality of recovery from anesthesia.

Utilização de alfentanil, sufentanil e fentanil em cães anestesiados com halotano

Opioid analgesics promote intense analgesia allowing reduction of the concentration of the inhalation anesthetics what minimizes the cardiovascular depression that occurs during anesthesia. Many opioid agents are used during anesthesia. Fentanil, alfentanil and sufentanil are among the most potent agents being preferentially used transoperatively. In the present study, the cardiovascular action of this three agents were compared during inhalation anesthesia in dogs submitted to orthopedic procedures, as well as the possibility of maintenance of anesthesia with halothane in low concentrations. Three groups of ten animals were employed in the experiment. After anesthesia stabilization, animals of group I received intravenously (IV) 5µg/kg of fentanil, animals of group II 1µg/kg of sufentanil IV and animals of group III 25µg/kg of alfentanil IV. Cardiovascular and respiratory parameters were evaluated in various time points. Data were statistically analyzed by means of analyses of variance for repeated measures followed by the Dunnett and Bonferoni post tests.All three agents caused bradicardia during the observation period but only alfentanil promoted significant hypotension. Only one animal that received fentanil showed increase of blood pressure and heart rate simultaneously during anesthesia. At recovery more animals treated with alfentanil showed signs of excitation. With the results obtained the authors could conclude that the use of opioids during anesthesia yield the use of low concentrations of halothane, what contributes with blood pressure maintenance. Among the agents utilized alfentanil promotes more pronounced cardiovascular effects.

O sevofluorano em psitacídeos (Amazonas aestiva): determinação da dose mínima (d. a. m) para produção de anestesia geral

Ten adult psittacines (Amazonas aestiva) were used. After appropriate immobilization the anesthetic induction was accomplished with facial mask connect to modified circuit of Maggil using 6V% of Sevofluorano with oxygen flow rate at 1.5/. The Minimal Anesthetic Concentration was determined in a manner similar to that proposed by LUDDERS et al. (1990). The MAC obtained was 3.44V%, higher than MAC. proposed to mammals. Sevoflurane can be used safely in avian species once it did not alter significantly all physiological parameters analyzed.

Evaluation of Ventral Laparoscopic Abomasopexy Using Surgical Staples Associated with Suture Material in Dairy Cattle

Background: Displaced Abomasum is known for being on of the main illnesses that affect milking cows. Increase in diagnosis of this illness is due to advancement in diagnosis techniques. Increase in incidence of this illness can be explained by genetic selection of animals with high production, breed systems and changes to the diet with a higher level of protein. For laparoscopic treatment, several surgical changes were performed to optimize the procedure and thus achieve better results. The main purpose of this study was to evaluate applicability of the ventral laparoscopic abomasopexy technique, using surgical clamps attached to the suture thread, to milking cows. Materials, Methods & Results: Six adult cows were placed under anesthesia with isoflurane and placed in dorsal decubitus. Animals were kept with no water for 24 h and no food for 48 h. Four laparoscopic accesses were performed. The first one was created with the intention of inspecting the abdominal cavity and the remaining three for access of surgical instruments. Serous membrane of the abomasum was cauterized, combined with suture threads and placed at the greater abomasal curvature. The free part of suture threads was kept out of the abdominal cavity and after traction of the abomasum against the abdominal wall was tied to the skin. Ultrasound exam was performed for abdominal evaluation after abomasopexy. Anesthesia time and surgery time were recorded and analyzes through average and standard deviation (SD). The average anesthesia time recorded was 94 min (SD 14.63 min) and average surgery time was 51 min (SD 14.71 min). The fasting period was considered adequate, however all animals had to undergo intubation with orogastric tube to drain liquids and gas during the procedure. Four of the six animals had lineal adhesion. Three of the four animals that had adhesion did not keep the abomasum at the retroperitoneal area, however viscera movement was stopped in the abdominal cavity. Discussion: Abomasopexy through laparoscopy is a safe technique, especially when compared with other invasive methods of abomasopexy. However, to perform this type of surgery availability of adequate equipment and a well trained surgical team are required. This study was performed at a surgery room under full anesthesia. In a field situation, the veterinarian can have some difficulties but such adversities must not be considered and impediment for performance of surgery on the field as its performance is possible. Even though surgical clamps were small, they were considered adequate for what was suggested. The applied 0 degree laparoscopic optic presented restrictions for cavity inspection, therefore we believe that an optical lenses with 30 degree angle could facilitate this laparoscopy inspection. To induce greater and more lasting adherence we suggest cauterizing a greater area of the serous membrane of the abomasum. We also suggest not performing this procedure during lactation peak, when fasting and surgery can cause economic losses. Complications associated with this technique could not be avoided. The technique has shown favorable results, but its clinical applicability depends on application on animals subjected to the conditions of a milk production cycle.

Effect of postoperative xylazine administration on cardiopulmonary function and recovery quality after isoflurane anesthesia in horses: Xylazine in Horses for Anesthetic Recovery

OBJECTIVE To evaluate equine cardiopulmonary function and recovery quality after administration of 0.25 or 0.50 mg/kg xylazine intravenously (IV) during recovery. STUDY DESIGN Randomized, blinded, prospective, clinical study. ANIMALS Horses (n = 20). METHODS During recovery after 3 hours of isoflurane anesthesia for arthroscopic surgery, horses were administered either 0.25 mg/kg (G25, n = 10) or 0.50 mg/kg (G50, n = 10) xylazine intravenously. Vital signs and arterial blood samples were obtained during recovery before sedation (baseline), 5, 10, 20, 30, and 45 minutes after xylazine and 30 minutes after standing. The quality of recovery scores ranged from 10 to 72 (10 = best, 72 = worst). RESULTS G25 horses recovered faster (mean ± SD, 33 ± 5 min) than G50 horses (50 ± 7 min, P < .0001). Mean maximal decrease in arterial oxygen tension was 55 ± 11 mmHg in G25 (at 10 minutes; P < .05) and 54 ± 7 mmHg in G50 (at 20 minutes; P < .01). G25 group had a total recovery score (23 [range 18-29]) and number of attempts to stand (4 ± 2) greater than the G50 group (18 [10-23] and 1 ± 1, respectively; P < .001). CONCLUSIONS Both doses of xylazine promoted a moderate and transient hypoxemia during recovery; however, the 0.5 mg/kg dose produced a longer and improved quality of recovery from anesthesia.