Ultrasound guided periconal anesthesia

Abstract

Periconal anesthesia has long been the choice technique for ophthalmic surgery. As in other areas of regional anesthesia, ultrasound guided injection of local anesthesia might improve the quality and safety of Periconal anesthesia by visualization of the needle placement. However, there is a lack of published data worldwide on the use of ultrasonography-assisted ophtalmic regional anesthesia. The eye is easily accessible, its geometry and surrounding elements are relatively straightforward, and the tissue contents of the orbit lack gas-filled or bony structures, making this an ideal area for ultrasonic imaging. Thus, ultrasonography may have application in improving the safety profile of ophthalmic regional blocks, particularly globe perforation or penetration associated with the needle-based techniques. Therefore, this research aims to elucidate the real benefit of the ultrasound as a guide in ophthalmologic blocks on the occurrence of complications. Methods: This is a prospective observational study. Upon obtaining approval by the Ethics in Research UNIRIO and informed consent, ASA I-II patients undergoing cataract surgery will be considered for the study. But, patients with single eye, in emergency situations, not collaborative and high myopia (axial length greater than 26 mm) with the presence of staphyloma, will be excluded. A sample of 30 patients, randomly divided into two groups, will be evaluated. After sedation and standardized monitoring, a periconal blockade (25x0, 6mm needle) ultrasound guided or not, with 5 mL of 0.75% bupivacaine containing Hyalozima 40UI/ml will be performed. The U.S. device to be used in the study is the DGH ScanMate B-Scan Model 8000 Version 2.10.3 / Probe DLL Version: 00.61. Resolution: Electronic, 0.015 mm; Clinical, <0.1 mm. The physical characteristics of this device are consistent with the recommendations of the Food And Drug Administration (FDA) and Health Canada (mechanical index of ultrasound waves <23 and a maximum thermal index). (AU)