Munawar Kamran, Khan Muhammad Tariq, Hussain Syed Waqar, Qadeer Aayesha, Shad Zahid Siddique, Bano Sheher, Abdullah Azmat
Internal Medicine, Shifa International Hospital, Islamabad, PAK.
Internal Medicine, Khan Research Laboratories Hospital, Islamabad, PAK.
Cureus. 2019 Feb 27;11(2):e4145. doi: 10.7759/cureus.4145.
Background The early detection of elevated intracranial pressure (ICP) can not only prevent mortality but also aid in more aggressive management. Brain computed tomography (CT) is a mainstay modality in detecting elevated ICP, but the feasibility of using brain CTs to detect elevated ICP in critically ill patients is limited, especially for patients who require high levels of inotropic support. The optic nerve sheath is a direct extension of the brain meninges. Therefore, the elevation of ICP is directly transmitted to the sheath. Measuring the optic nerve sheath diameter (ONSD) through ultrasound (US) is a bedside, noninvasive means to detect elevated ICP. The goal of this study was to assess the correlation of ONSD with elevated ICP as measured via US in an intensive care unit (ICU). Methods We conducted a six-month prospective, single-center, observational study of mass effect stroke patients aged 18 to 65 years who had a traumatic brain injury (TBI) and were admitted to the ICU. Patients with chronic hydrocephalus, extensive local orbit trauma, a pre-existing ocular disease affecting the optic nerve and/or orbital cavity, hyperthyroidism with exophthalmos, and facial trauma affecting the orbits and/or eyeballs were excluded. We measured the ONSD at the entry of optic nerve into the globe using two-dimensional (2D) US. Results One hundred patients were included in the study. Forty-nine patients had diffuse cerebral edema detected on CT scan correlating with increased ONSD notable via bedside US. The mean ONSD related to CT-detectable elevated ICP was 0.61 cm. The sensitivity for the ONSD cut-off value of ≥5.8 mm was 94% (95% confidence interval [CI], 84.05% to 98.79%), and the specificity was 96.08% (95% CI, 86.7% to 99.52%).The positive predictive value was 92.08% (95% CI, 86.28% to 98.96%), and the negative predictive value was 94.23% (95% CI, 84.47% to 98.00%). Conclusion The greatest accuracy in ONSD was found with a cut-off of >0.58 cm in patients with positive CT brain findings. Therefore, US can be used as an initial screening test when physicians suspect a patient has elevated ICP.
背景 早期检测颅内压（ICP）升高不仅可以预防死亡，还有助于更积极的治疗。脑部计算机断层扫描（CT）是检测ICP升高的主要手段，但在危重症患者中使用脑部CT检测ICP升高的可行性有限，尤其是对于需要高水平血管活性药物支持的患者。视神经鞘是脑膜的直接延伸。因此，ICP升高会直接传递到鞘膜。通过超声（US）测量视神经鞘直径（ONSD）是一种床边无创检测ICP升高的方法。本研究的目的是评估在重症监护病房（ICU）中，通过US测量的ONSD与ICP升高之间的相关性。方法 我们对18至65岁、患有创伤性脑损伤（TBI）并入住ICU的占位效应性卒中患者进行了为期6个月的前瞻性、单中心观察性研究。排除患有慢性脑积水、广泛的局部眼眶创伤、既往存在影响视神经和/或眼眶腔的眼部疾病、伴有突眼的甲状腺功能亢进症以及影响眼眶和/或眼球的面部创伤的患者。我们使用二维（2D）US在视神经进入眼球处测量ONSD。结果 100名患者纳入研究。49名患者在CT扫描中检测到弥漫性脑水肿，与床边US检测到的ONSD增加相关。与CT可检测到的ICP升高相关的平均ONSD为0.61 cm。ONSD临界值≥5.8 mm时的敏感性为94%（95%置信区间[CI]，84.05%至98.79%），特异性为96.08%（95%CI，86.7%至99.52%）。阳性预测值为92.08%（95%CI，86.28%至98.96%），阴性预测值为94.23%（95%CI，84.47%至98.00%）。结论 在脑部CT检查结果为阳性的患者中，当ONSD临界值>0.58 cm时，准确性最高。因此，当医生怀疑患者ICP升高时，US可作为初步筛查试验。
