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.

Orthognathic surgery with or without induced hypotension

This study involved a retrospective evaluation of patients subjected to surgery for dentofacial deformities treated without induced controlled hypotension (group I, n = 50) and a prospective evaluation of patients who were subjected to surgery under hypotensive general anaesthesia (group II, n = 50). No statistical differences were found between the study groups with regard to the duration of surgery. However, there were statistically significant differences in the need for blood transfusion and the occurrence of bradycardia during the maxillary down-fracture. Hypotensive anaesthesia decreased the need for a blood transfusion and the occurrence of bradycardia, and is therefore considered highly beneficial for patients undergoing orthognathic surgery.

Ocular ultrasonography and ultrasound biomicroscopy: applicability in clinical and ophthalmic surgery

With the advent of high frequency transducers, the use of ocular ultrasound has become widely used because it provides definitions of major ocular structures. This diagnostic tool is useful in the evaluation of ophthalmic injuries, and also used for qualitative and quantitative evaluation of intraocular and orbital lesions. It is a noninvasive, safe and fast, easy to use and can be performed in an awake animal. The ocular ultrasonography is indicated in cases of ocular opacity, when the ophthalmic examination cannot be done, and in eyes with ocular trauma or suspected orbital disease. Ultrasound biomicroscopy (UBM) is a diagnostic tool with high cost and sedation or general anesthesia is necessary, but has the advantage of evaluating structures poorly defined or visualized in the anterior segment of the eye. Therefore, this paper aims to show the importance of ocular ultrasonography and UBM to veterinary practitioners, and to demonstrate its advantages and indications in ophthalmic routine.

Evaluation of DNA damage and lipoperoxidation of propofol in patients undergoing elective surgery

Inhaled anaesthetics have been studied regarding their genotoxic and mutagenic potential in vivo. Propofol differs from volatile anaesthetics because it does not show mutagenic effects and it has been reported to be an antioxidant. However, there are no studies with propofol and genotoxicity in vivo. The study aimed to evaluate the hypothesis that propofol is not genotoxic and it inhibits lipid peroxidation [malondialdehyde (MDA)] in patients undergoing propofol anaesthesia. ASA physical status I patients scheduled for elective surgery, lasting at least 90 min, were enrolled in this study. Initially, the estimated plasma concentration of propofol was targeted at 4 microg ml(-1) and then maintained at 2-4 microg ml(-1) until the end of surgery. Haemodynamic data were determined at baseline (before premedication) and in conjunction with target-controlled infusion of propofol: after tracheal intubation, 30, 60 and 90 min after anaesthesia induction and at the end of the surgery. Venous blood samples were collected at baseline, after tracheal intubation, at the end of the surgery and on the postoperative first day for evaluating DNA damage in white blood cells (WBCs), by comet assay, and MDA levels. Haemodynamic data did not differ among times. No statistically significant differences were observed for the levels of DNA damage in WBCs, nor in plasma MDA, among the four times. Propofol does not induce DNA damage in WBCs and does not alter MDA in plasma of patients.

Isoflurane and propofol contribute to increasing the antioxidant status of patients during minor elective surgery: a randomized clinical study

Isoflurane is a volatile halogenated anesthetic used especially for anesthesia maintenance whereas propofol is a venous anesthetic utilized for anesthesia induction and maintenance, and reportedly an antioxidant. However, there are still controversies related to isoflurane-induced oxidative stress and it remains unanswered whether the antioxidant effects occur in patients under propofol anesthesia.Taking into account the importance of better understanding the role of anesthetics on oxidative stress in anesthetized patients, the present study was designed to evaluate general anesthesia maintained with isoflurane or propofol on antioxidant status in patients who underwent minimally invasive surgeries.We conducted a prospective randomized trial in 30 adult patients without comorbidities who underwent elective minor surgery (septoplasty) lasting at least 2 h admitted to a Brazilian tertiary hospital.The patients were randomly allocated into 2 groups, according to anesthesia maintenance (isoflurane, n = 15 or propofol, n = 15). Peripheral blood samples were drawn before anesthesia (baseline) and 2-h after anesthesia induction.The primary outcomes were to investigate the effect of either isoflurane or propofol anesthesia on aqueous plasma oxidizability and total antioxidant performance (TAP) by fluorometry as well as several individual antioxidants by high-performance liquid chromatography. As secondary outcome, oxidized genetic damage (7,8-dihydro-8-oxoguanine, known as 8-oxo-Gua) was investigated by the comet assay.Both anesthesia techniques (isoflurane or propofol) for a 2-h period resulted in a significant decrease of plasma α-tocopherol, but not other antioxidants including uric acid, carotenoids, and retinol (P > 0.05). Propofol, in contrast to isoflurane anesthesia, significantly increased (P < 0.001) anti-inflammatory/antioxidant plasma γ-tocopherol concentration in patients. Both anesthesia types significantly enhanced hydrophilic antioxidant capacity and TAP, with no significant difference between them, and 8-oxo-Gua remained unchanged during anesthesia in both groups. In addition, both anesthetics showed antioxidant capacity in vitro.This study shows that anesthesia maintained with either propofol or isoflurane increase both hydrophilic and total antioxidant capacity in plasma, but only propofol anesthesia increases plasma γ-tocopherol concentration. Additionally, both types of anesthetics do not lead to oxidative DNA damage in patients without comorbidities undergoing minimally invasive surgery.

Longer immediate recovery time after anesthesia increases risk of respiratory complications after laparotomy for bariatric surgery: a randomized clinical trial and a cohort study

We compared the effects of two anesthesia protocols in both immediate recovery time (IRT) and postoperative respiratory complications (PRCs) after laparotomy for bariatric surgery, and we determined the association between the longer IRT and the increase of PRC incidence. We conducted the study in two stages: (i) in a randomized controlled trial (RCT), patients received either intervention (sevoflurane-remifentanil-rocuronium-ropivacaine) or control protocol (isoflurane-sufentanil-atracurium-levobupivacaine). All patients received general anesthesia plus continuous epidural anesthesia and analgesia. Treatment was masked for all, except the provider anesthesiologist. We defined IRT as time since anesthetics discontinuation until tracheal extubation. Primary outcomes were IRT and PRCs incidence within 15 days after surgery. We also analyzed post-anesthesia care unit (PACU) and hospital length of stays; (ii) after the end of the RCT, we used the available data in an extension cohort study to investigate IRT > 20 min as exposure factor for PRCs. Control protocol (n = 152) resulted in longer IRT (30.4 ± 7.9 vs 18.2 ± 9.6 min; p < 0.0001), higher incidence of PRCs (6.58 vs 2.5 %; p = 0.048), and longer PACU and hospital stays than intervention protocol (n = 200); PRC relative risk (RR) = 2.6. Patients with IRT > 20 min (n = 190) presented higher incidence of PRCs (7.37 vs 0.62 %; p < 0.0001); RR = 12.06. Intervention protocol, with short-acting anesthetics, was more beneficial and safe compared to control protocol, with long-acting drugs, regarding the reduction of IRT, PRCs, and PACU and hospital stays for laparotomy in bariatric patients. We identified a 4.5-fold increase in the relative risk of PRCs when morbid obese patients are exposed to an IRT > 20 min.