Inter-rater reliability of optic nerve sheath diameter measurement using real-time ultrasonography

Objectives Ultrasound measurement of the optic nerve sheath diameter (ONSD) is a rapid, non-invasive means to indirectly assess intracranial pressure. Previous research has demonstrated the ability of emergency physicians to measure ONSD accurately with bedside ultrasound when compared to CT scan or MRI, however the reliability of this measurement between two or more operators has been called into question (Hassen et al. in J Emerg Med 48:450–457, 2015; Shirodkar et al. in Ind J Crit Care Med 19:466–470, 2015). Given the need for accurate and precise measurement to use this as a screening exam, we sought to determine the inter-rater reliability between ONSD measurements obtained in real time by fellowship-trained emergency ultrasound physicians. Methods Three ultrasound fellowship-trained emergency physicians measured bilateral ONSD of 10 healthy volunteers using a high-frequency linear transducer. The physicians were blinded to the other scanners’ measurements, and no instructions were given other than to obtain the ONSD. Each sonographer measured the ONSD in real time and it was recorded by a research coordinator. All measurements were recorded in millimeters. Intraclass correlation coefficients (ICCs) were calculated to estimate the inter-rater reliability. Results A total of 60 measurements of ONSD were obtained. The average measurement was 4.3 mm (3.83–4.77). Very little variation was found between the three physicians, with a calculated ICC of 0.82 (95% confidence interval 0.63–0.92). Conclusions ONSD measurement obtained by ultrasound fellowship-trained emergency medicine physicians is a reliable measurement with a high degree of correlation between scanners.

Idiopathic Intracranial Hypertension: Current Neuroophthalmologic Points

Idiopathic intracranial hypertension (ICH) is a neuroophophthalmologic syndrome, the main ophthalmologic symptoms of which are vision loss and bilateral swelling of optic nerve disks (OD). The article provides a review covering various aspects of ICH. Epidemiology: ICH occurs mainly in women aged 20–45 years with body overweight. In this group of patients world incidence is 12–20 per 100 000 of population per year. In the total population it represents 0.5–2 cases per 100 000 of population per year. The eightfold gender predominance of women with ICH is observed. Etiology is not fully known until present time. The reliable connection between obesity in childbearing age women and menstrual cycle disorders as evidences of hormonal changes has been established. The probable mechanisms of increase of ICP are supposed: hyperproduction of and disturbances of its absorption, CSF mechanical pressure on the optic nerve sheath; restriction of venous outflow from the brain due to the pathology of venous sinuses; stimulating effect of abundant vitamin A in diet resulting in the fat tissue formation with the development of obesity; expression of the protein aquaporin, involved in the regulation of body mass and water metabolism in the subarachnoid space. Clinical manifestations. Ophthalmologic symptoms of ICH: transient visual impairment, sustained loss of visual acuity, photopsy, retrobulbar pain, diplopia. Non-ophthalmologic symptoms: headache, throbbing tinnitus, hearing loss, dizziness. Diagnostics. The valuable diagnostic data can be obtained by visual field investigation, ophthalmoscopic examination with revealing of bilateral OD-edema, OD and retinal optical coherent tomography, orbital ultrasound examination, brain MRI with venography. Treatment. Non-drug therapy: weight loss, lowcalorie diet with limited water and salt intake. Drug therapy: long-term oral use of carbonic anhydrase inhibitors (acetazolamide, topiramate). High doses of steroids (methylprednisone) are used for short-term treatment of patients with fulminant disease type before surgery. Surgery: bypass surgery, cerebral venous sinus stenting and fenestrations of the optic nerve sheath: bariatric surgery with reducing of stomach volume.

Effects of Increased Optic Nerve Sheath Diameter on Inadequate Emergence from Anesthesia in Patients Undergoing Robot-Assisted Laparoscopic Prostatectomy: A Prospective Observational Study

(1) Background: Robot-assisted laparoscopic prostatectomy (RALP) is preferred over open prostatectomy because it offers superior surgical outcomes and better postoperative recovery. The steep Trendelenburg position and pneumoperitoneum required in Robot-assisted laparoscopic prostatectomy, however, increase intracranial pressure (ICP). The present study aimed to evaluate the effects of elevated ICP on the quality of emergence from anesthesia. (2) Methods: Sixty-seven patients undergoing RALP were enrolled. We measured optic nerve sheath diameter at four timepoints during surgery. Primary outcome was inadequate emergence in the operating room (OR). Secondary outcomes were postoperative neurologic deficits of dizziness, headache, delirium, cognitive dysfunction, and postoperative nausea and vomiting (PONV). (3) Results: A total of 69 patients were screened for eligibility and 67 patients completed the study and were included in the final analysis. After establishing pneumoperitoneum with the Trendelenburg position, ONSD increased compared to baseline by 11.4%. Of the 67 patients, 36 patients showed an increase of 10% or more in optic nerve sheath diameter (ONSD). Patients with ΔONSD ≥ 10% experienced more inadequate emergence in the OR than those with ΔONSD < 10% (47.2% vs. 12.9%, p = 0.003). However, other variables related to the quality of emergence from anesthesia did not different significantly between groups. Similarly, neurologic deficits, and PONV during postoperative day 3 showed no significant differences. (4) Conclusions: ICP elevation detected by ultrasonographic ONSD measurement was associated with a transient, inadequate emergence from anesthesia.