The Use of Ocular Nerve Sheath Diameter Measurements to Record Intracranial Pressure - Essay Example

27th June The use of Ocular Nerve Sheath Diameter measurements to record Intercranial Pressure If not timely addressed, increased intracranial pressure (ICP) may result to damaging of brain as the result of restriction of blood flow or compression of the brain structures. Despite the improved technology in the medical field, physicians and medics as well as other healthy care providers have been by few methods to noninvasively notice the increased rate of intracranial pressure. Notably, the medics have faced some challenges when detecting the increased rate of ICP among the acutely ill patients at the bedside. While some physicians rely on physical examination, this method has limitations especially in the cases where the patient is intubated, paralyzed or unconscious. In this regard, physicians in the modern hospital settings have embarked on adopting reasonably advanced methods including magnetic resonance imaging, computed tomography and lumbar puncture (Blaivas et al 796).Through the extensive research by the medical personnel, the use of sonography as a technique of detecting the hiking ICP has been noted to produce more reliable results. It is imperative to note that patients with different levels of consciousness may be suffering from ICP as the result of various factors. For example, patients with spontaneous intracranial bleed as well as those with head injuries may suffer from an elevated intercranial pressure. In such cases, the patients may be unconscious thus making the physical examination to be difficult. At the same time, despite the increase in ICP, the papilledema from elevated intercranial pressure may take some time. This implies that medics should have a speedy as well as noninvasive ways of detecting the elevated intercranial pressure during the time when the conventional imaging techniques are not accessible. Ocular Nerve Sheath Diameter (ONSD) is a significant way that medics have now turned to in measuring, evaluating and recording of intercranial pressure. The evaluation process is non-invasive making it a useful tool in detecting an increased intercranial pressure. Having being described in various cadavers within different research centers, ocular sounds have been used as evidence of increased intercranial pressure. According to the data that has been acquired from various clinical settings, it has been noted that the increased level of intercranial pressure have indicated positive correspondence with the increases in millimetric in the optic nerve sheath diameter (Blaivas et al 379) . It is vital to note that the relationship on the level ICP and ONSD is significantly caused by the location of the optic nerve in the body of a human being. Being part of the central nervous system, the optic nerve provides adequate information that assists the ONSD in its duties. On its part, the optic nerve sheath entails the continuation of the dura mater that encircles the optic nerve. One of the major aspects that make Ocular Nerve Sheath Diameter to provide strong evidence in detection of ICP is the existence of subarachnoid space. Subarachnoid, is the communicating space that relays information to and from the central nervous system (CNS). The subarachnoid space, which is located between the optic nerve sheath and the optic nerve, provides the information from the CNS in a timely manner (Price et al 86). Whenever there is a change in pressure within the intercranial cavity, the changes are communicated to the optic nerve sheath through the subarachnoid space. As a result, the diameter of the sheath is affected which is easily noted by the medics attending the patient. As the process continues and the intercranial pressure continues to increase, more results that are helpful to the medics are generated. These include the swelling of papilledema and the optic disc. It is vital to note that during the process of treating the patients, medics should differentiate moderate level of ICP and an acute one. This is based on the fact that in the case the ICP has risen to an acute level, the papilledema may take a long time to swell and there may be a possibility that the ICP of the patient could have increased a long time ago yet the signs were not showing. One of the major aspects of Ocular Nerve Sheath Diameter and papilledema is that both have similar mechanisms. However, in the case of Ocular Nerve Sheath Diameter the changes occur within a very short time after the increment of the ICP (Major et al 82). Thus, the rapid response by the Ocular Nerve Sheath Diameter makes it helpful in a hospital setting to detect acute as well as hyper-acute increase in intercranial pressure. By evaluating the optic nerve sheath diameter, medics can easily detect the elevated intercranial pressure. A normal optic nerve sheath on ultrasound has a diameter of 5.0 mm (Newman1 et al 1112). By measuring the Ocular Nerve Sheath Diameter 3mm posterior behind the globes of the eyes, it makes the ultrasound contrast to be greater thus ensuring that the results are more effective. In order to get more reliable results, an average of two measurements is computed. If the measurement of Ocular Nerve Sheath Diameter is more than 5mm, the case is treated as abnormal and the medics should suspect and look for elevated intercranial pressure. During the performance of the examination by the medics, sonographers recommend the use of resolution of 7.5 to 10MHz. In this way, it will be possible to view small details that will be used in analyzing the whole condition of the patient. Studies by various professionals in the medical field indicate that there is a strong correlation between the level of intercranial pressure and Ocular Nerve Sheath Diameter in terms of the use of ocular ultrasounds in noticing and evaluating the intracranial hypertension (Duschek and Schandry 73). In one of the studies, more that one hundred patients who were diagnosed with brain tumors, subarachnoid, intracranial hemorrhage and traumatic brain injury, the researchers also indicated that there is a strong evidence of intra as well as interobserver reliability between increased ICP and ONSD. According to Blaivas et al, ocular ultrasounds have been mostly used among the adults who are admitted in the emergency departments after being suspected to be having an elevated intercranial pressure. One of the major limitations of using the Ocular Nerve Sheath Diameter is that it is unable to be used on some patients especially the one suffering from ocular trauma for example an open globe injury. This is based on the fact that the implications of ocular trauma on measurements obtained from ONSD are unclear. Another issue that affects the effectiveness the use of Ocular Nerve Sheath Diameter among the medics is lack of experience and necessary skills in the use of the modern technologies. However, such a limitation can be addressed by ensuring that the inexperienced providers are allocated minimum number of supervised tasks during the measurement of optic nerve sheath diameters (Stephanie et al 21). While experienced providers are in a position to obtain less than 10 measurements and approximately three abnormal scans, inexperienced sonographers should take up to 25 scans in order to obtain reliable measurements (Paldino et al 26). Notable factors that may cause differences in the ONSD measurements could be caused by the position of the globe as well as the model of the ultrasound device being applied by the sonographer. Based on the above discussion, it is clear that in the modern medical atmosphere, ultrasound is emerging to be a medical fixture. Having being an important way through which increased ICP can be addressed, the use Ocular Nerve Sheath Diameter has significantly led to solving of serious issues that touches on patients at their bedside. This implies that more research should be undertaken in order to make the process more effective. One of the areas that needs more research is on to ensure that the measurements as indicated by ONSD are as accurate as possible. This will ensure that the sonographers are in a position to effectively deal with the problems faced by the patients. During the cases of acute-elevated ICP, it is risky to use portable ultrasound to get the ONSD measurements (Bauerle and Nedelmann 2014). This implies that there is need for a more research of handling such cases instead of evacuating the patients to a higher level facility. In this way, it would be possible to reduce the number of death and complications associated with increased ICP. Another notable area that needs to be researched on is how to improve the performance of Special Forces medical providers. As noted earlier, lack of experience is an obstacle to effective performance of providers (Dewitz 15). Thus, by coming up with goal oriented and quality training that entails extensive practical, the providers will be in a position to deal with increased ICP and recording of Ocular Nerve Sheath Diameter measurements. Works Cited Bauerle, J. and Nedelmann, M. Sonographic assessment of the optic nerve sheath in idiopathic intracranial hypertension. J Neurol, 258: 2014-9. Blaivas, M, Theodoro, D and Sierzenski, P.   Elevated intracranial pressure detected by bedside emergency ultrasonography of the optic nerve sheath. Acad Emer Med.2003; 10: 376-381. Blaivas, M, Theodoro, D and Sierzenski, P.   A study of bedside ocular ultrasonography in the emergency department. Acad Emer Med.2002; 9:791-799. Dewitz, A.  Soft tissue applications. McGraw- Hill: New York. Duschek, S and Schandry, R. Reduced brain perfusion and cognitive performance due to constitutional hypotension. Clinical Autonomic Research 2007 17 (2): 69–76. Major, R, Girling, S and Boyle, A. 2011. Ultrasound measurement of optic nerve sheath diameter in patients with a clinical suspicion of raised intracranial pressure. Emerg Med J, 28(8) 79-83. Newman1, W et al. Measurement of optic nerve sheath diameter by ultrasound: a means of detecting acute raised intracranial pressure in hydrocephalus. Scientific correspondence, 2002; 86:1109-1113. Paldino, M, Mogilner, Y and Tenner, M. Intracranial hypotension syndrome: a comprehensive review. Neurosurg Focus 2003 15 (6): ECP2. Price D, Simon, C and Park, S.   Evolution of emergency ultrasound. California J Emerg Med.2003; 4: 82-84. Stephanie, H et al. Detection of Increased Intracranial Pressure by Ultrasound. Journal of special Operations Medicine 2012. Volume 12, 3 Available from http://depts.washington.edu/doemuw/files/pdf/Intracranial_Pressure.pdf Read More