الفهرس 
Chapter 1: Intra cranial pressureOnly 14 pages are availabe for public view
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Abstract
Elevated intracranial pressure is a life-threatening condition which caused by different neurological and non-neurological disorders (Antonelli M et al., 2009). Invasive intracranial methods are still the gold standard for measuring intracranial pressure. (Hwan KimY et al., 2014).
In case of the hard availability of the invasive intracranial devices or contraindicated in some situations, there are noninvasive methods such as bedside tools and neuroimaging have been developed for quick measurement and assessment.
Ultrasonographic (USG) measuring of optic nerve sheath diameter (ONSD) shows increased interest in the last years. As the reason is ultrasonography has become a simple bedside tool commonly used in emergency situations .The equipment needed is usually available, and with less cost. The ICP could be indirectly evaluated through the measurement of optic nerve subarachnoid space (Liu H et al., 2018).
This study aimed to evaluate the diagnostic accuracy of ultrasonography of optic nerve sheath diameter (ONSD) in diagnosis and follow up in patient admitted at intensive care unit with clinically suspected increased ICP.
Our study was conducted in the ICU of Fayoum University Hospitals, from January 2020 to September 2021, 141 participants were enrolled in our study who were divided into 76 cases (patients) who had been admitted with disturbed conscious level due to elevated ICP and 65 controls.
All patients were subjected to full medical history, detailed physical examination, and the following investigations in the form of:
-Laboratory investigations: including (CBC, Coagulation profile, Liver function tests, Kidney function tests, Blood sugar, and Serum electrolytes including Na, K and Ca.
-Ocular ultrasound, Brain computed tomography (CT) and Fundus examination.
The current study showed that ONSD is significant in prediction of elevated ICP at cut-off point of average ONSD 5.19 mm with 97.4 % sensitivity and 98% specificity and the area under curve [AUC] was 0.996.
In our study, ONSD increased in all studied patients with significant higher value in patient with CT evidence of increased ICP than those without (6.45± 0.59 vs 6.06 ± 0.38) with significant p-value 0.001 and the optimal cut-off point of average ONSD for patients with of evidence of radiological finding of increased ICP was 5.90 with a sensitivity of 82 % and a specificity of 51%.
ONSD also had superior predictive value for increased ICP compared to classical CT findings of intracranial hypertension as a normal CT scan does not exclude a raised ICP.
There was negative significant correlation between ONSD and GCS (r = -0.237, p-value 0.040) on admission and (r =-0.404, p-value <0.0001) after 48 hrs.
There was positive correlation between Fundoscopic examination and ONSD increased significally with increasing the grades of fundus examination. Significant higher values in patient had papilledema with average ONSD (P value 0.006). But, many patients with no papilledema show increased ONSD measurements. That support ONSD is more sensitive marker to detect papilledema than fundus examination.
We found that ONSD had valuable role in patient with metabolic diseases presented with DCL more than CT brain and fundoscopy which usually appeared normal without signs of elevated of ICP or appeared late.