Baricity: an important issue for spinal anesthesia

Abstract

Hip fractures occur 1.6 million times worldwide every year.1 This patient population has specific problems. General anesthesia and spinal anesthesia represent the two common approaches for these groups of patients. Compared to general, spinal anesthesia is simple and easy; it provides pain control, reduces mortality and early cognitive dysfunction.2, 3 The major disadvantages of spinal anesthesia are risks of hypotension, higher level of blockade and cardiac arrest. Intrathecal drug distribution is affected by a number of factors, including baricity, total dose, volume, concentration of the local anesthetic drug, injection site, conformation of spinal canal (presence of kyphosis, lordosis), position and cerebrospinal fluid (CSF) volume in the lumbosacral dural sac. Baricity is the ratio of density of the local anesthetic solution relative to the density of CSF at 37 °C. Isobaric solution is as the same density as the CSF. Hyperbaric solution is denser than CSF, whereas hypobaric solution is less dense than CSF. Thus, the choice of the drug baricity can be affected by patient position. Isobaric solutions have minimal effects on distribution of anesthetic and cephalad spread of spinal anesthesia. It can be an advantage for orthopedic surgery. Hypobaric local anesthetics are suitable for hip surgery in the lateraldecubitus position, because of its selectively to distribute to the non-dependent (operative) side with no extra movement of the anesthetized patient. The other advantage of hypobaric solutions is a slight head down position keeps the level of blockade from rising and, at the same time, improves venous return and hemodynamic stability.4 Levobupivacaine is one of the less cardiotoxic and neurotoxic local anesthetic drugs and it can be used for orthopedic surgery patients. Its pharmacologic properties are similar to bupivacaine but electrolyte composition is different. Levobupivacaine has a higher sodium content, osmolality and H+ ion concentration compared with bupivacaine. When the concentration of levobupivacaine is increased, sodium ion concentration is held constant, but as the concentration of bupivacaine is increa bupivacaine is increased, sodium concentration is reduced.5 In this issue of Minerva Anestesiologica, Vergari et al.6 assess a prospective randomized study comparing isobaric to hypobaric levobupivacaine for hip arthroplasty patients in lateral decubitus position. Using hypobaric levobupivacaine allows for a shorter onset time for sensory block and delayed regression of sensory and motor block in the non-dependent side without added complications. Isobaric and hypobaric bupivacaine were compared in the lateral decubitus position by Faust et al.7 Except for using levobupivacaine, results of that study were similar to those from the study by Faust et alEndoscopy is being frequently performed for both diagnostic and therapeutic applications in surgical practice. Surgery, as a scientific area, has an important role in the propagation of therapeutic endoscopic procedures. The contribution of surgeons to the evolution of endoscopic applications and its practice is a triggering factor for the improvement of endoscopic instruments and their widespread use. Training and education on basic diagnostic and therapeutic surgical endoscopy should be implemented as part of general surgery residency core program, according to accepted standardized criteria, in order for general surgeons to perform endoscopic applications in the future. In light of this information, it can be concluded that endoscopy training and skills should be standardized within accepted general principles. Standards to be used during post-graduate endoscopic practice should be precisely stated. In addition to accreditation of both surgeons and endoscopic centers, theoretical and practical education programs should be composed and organized.