The Effects of Lateral 45° Head-Down Position and Carbon Dioxide Pneumoperitoneum on the Optic Nerve Sheath Diameter in Patients Undergoing Laparoscopic Transperitoneal Nephrectomies: A Prospective Observational Study.

Background: The aim of this study is to assess the extent of the increased intracranial pressure resulting from lateral decubitus and 45° downward positioning using sonographic optic nerve sheath diameter (ONSD) in patients undergoing laparoscopic transperitoneal nephrectomy. In addition, we evaluated the effect of the carbon dioxide pneumoperitoneum (CO2PP) on ONSD. Materials and Methods: Twenty-four adults were enrolled in this prospective observational study. Longitudinal and transverse ONSDs were measured for each eye by ocular ultrasonography. The values were noted in supine position (T0), 20 minutes after induction of anesthesia (T1), after insufflation of the abdomen in lateral 45° head-down position (T2), at 30-minute intervals during surgery (T3-T4-T5), during lateral 45° head-down position after CO2 exsufflation (T6), before awakening while supine (T7), and at postoperative 24th hour (T8). Hemodynamic and respiratory parameters were investigated at the measurement time points. Results: Average ONSD values for the lower eye was T0 = 4.27 ± 0.4 mm, T1 = 4.56 ± 0.6 mm, T2 = 4.84 ± 0.6 mm, T3 = 4.91 ± 0.4 mm, T4 = 4.99 ± 0.5 mm, T5 = 4.97 ± 0.5 mm T6 = 4.96 ± 0.5 mm, T7 = 4.76 ± 0.4 mm, T8 = 4.36 ± 0.5 mm and for the upper eye was T0 = 4.24 ± 0.4 mm, T1 = 4.39 ± 0.5 mm, T2 = 4.54 ± 0.5 mm, T3 = 4.60 ± 0.4 mm, T4 = 4.66 ± 0.4 mm, T5 = 4.72 ± 0.7 mm, T6 = 4.68 ± 0.4 mm, T7 = 4.52 ± 0.4 mm, T8 = 4.30 ± 0.4 mm (P < .001). Conclusion: In our study, we observed a significant increase in ONSD within minutes after the patient was placed in a head-down position. We also observed that the difference increased more with CO2PP and was proportional to the length of the surgery. We found that it regressed to initial levels at the postoperative 24th hour. Clinicaltrials.gov: NCT05185908.

Dynamic Optic Nerve Sheath Diameter (ONSD) guided management of raised intracranial pressure in pediatric acute liver failure.

BACKGROUND AND AIMS: The objectives were to evaluate the role of optic nerve sheath diameter (ONSD) to detect raised intracranial pressure (ICP) in pediatric acute liver failure (PALF), study the variations in ONSD with ICP-lowering measures and to evaluate its prognostic role. METHODS: PALF with clinical evidence of raised ICP were enrolled as cases, while those without raised ICP were control group A. ONSD was measured at admission and repeated regularly. It was also measured at time of each new episode of raised ICP and 2 h after the management of such episode. RESULTS: 31 PALF with raised ICP were included as cases and 15 without as control group A. ONSD was significantly higher in cases: 5 mm (IQR: 4.7-5.4) as compared to control group A: 3.8 mm (IQR: 3.3-4). ONSD greater than 4.55 mm at baseline diagnosed clinically raised ICP with 87.5% sensitivity and 100% specificity. The mean ONSD was 5.44 ± 0.49 mm during a total of 90 events of acute raised ICP. Clinical responders had a decrease in ONSD by 0.59 ± 0.24 mm by 2 h, whereas non-responders showed a decrease of 0.18 ± 0.23 mm, p < 0.0005. ONSD persisting more than 4.6 mm by 24 h of management predicted poor outcome with sensitivity and specificity of 83.3% and 72.7%. CONCLUSION: ONSD is a simple, bedside, inexpensive, reproducible and repeatable modality to assess ongoing change in ICP in PALF. ONSD more than 4.55 mm suggests raised ICP. The goal should be to bring ONSD down to less than 4.6 mm within 24 h by aggressive anti-ICP therapy to achieve favourable outcome.

Sonography in acute ocular pathology: a kaleidoscopic view.

Ocular emergencies contribute to a large proportion of ocular pathologies. These may even be organ-threatening diseases such as central retinal artery and vein occlusion or globe rupture. Conventional physical examination may not always be feasible in emergency situations but decision-making in time is critical in the interest of patient in few of these conditions. Sonography in this setting plays an important role, allowing real-time, quick and dynamic evaluation. Common acute ocular pathologies such as retinal detachment, lens dislocation and globe rupture can be easily diagnosed by ultrasound. Vascular lesions can be identified using Doppler. This article illustrates the sonographic appearance in traumatic and non-traumatic acute ocular pathologies.

Terson's Syndrome: Diagnostic Comparison of Ocular Sonography and CT.

BACKGROUND AND PURPOSE: To assess the accuracy of ocular B-mode sonography and of standard head computed tomography (CT) as screening tools for intraocular hemorrhages related to subarachnoid hemorrhage (SAH). METHODS: 46 patients with spontaneous SAH were examined using ocular B-mode sonography and underwent funduscopy as gold standard for detection of ocular hemorrhages (OH). Additionally, all head CT scans done during the hospital stay of the study population were rated by a neuroradiologist for the presence of OH. RESULTS: Funduscopy revealed vitreous and/or preretinal hemorrhages in ten eyes and retinal hemorrhages in nine eyes. In comparison with funduscopy, ocular sonography showed a sensitivity and specificity for the detection of vitreous and/or preretinal hemorrhages of 100%, while identification of retinal hemorrhages was less reliable with a sensitivity/specificity of 44%/100%. Standard head CT showed a lower sensitivity/specificity of 60%/96% for vitreous and/or preretinal hemorrhages, and 32%/95% for the diagnosis of any ocular bleeding. CONCLUSION: Ocular sonography identifies SAH-related preretinal and vitreous hemorrhages with high accuracy and is superior to standard head CT. It may be considered as new and useful bedside diagnostic tool for routine clinical care of patients with SAH.

Correlation of measurement of optic nerve sheath diameter using ultrasound with magnetic resonance imaging.

BACKGROUND AND AIMS: Analysis to correlate the measurements of optic nerve sheath diameter (ONSD) obtained by using ultrasound to magnetic resonance imaging (MRI) techniques in order to establish the accuracy of ocular sonography as a noninvasive modality for detecting raised intracranial pressure (ICP). MATERIALS AND METHODS: A prospective, observational study was performed in 100 cases of adult meningoencephalitis patients admitted to Intensive Care Unit in whom MRI was performed for neurodiagnosis. ONSD was measured in such patients, 3 mm behind the globe in each eye. A mean binocular ONSD >4.6 mm in female and 4.8 mm in male was taken as cut-off values for diagnosing raised ICP. This was compared with ONSD measured on T2-weighted MRI image measured 3 mm behind the globe. The reading obtained from both the methods were compared with Bland-Altman analysis for correlation and the findings were tabulated. RESULTS: The mean ONSD values measured with ultrasonography (USG) and MRI for female were 5.48 ± 0.43 mm and 5.68 ± 0.44 mm and for male were 5.40 ± 0.37 mm and 5.56 ± 0.38 mm, respectively. The mean age of the female and male was 53.90 ± 17.84 and 56.06 ± 15.67 years, respectively. On comparing ultrasound with MRI-derived ONSD values, we found acceptable agreement between both methods for measurements at a depth of 3 mm (r = 0.02, P < 0.001). CONCLUSION: In our study, we have found a good correlation between ocular USG and MRI of ONSD. The study has shown agreement with the fact that ocular sonography can be used as a noninvasive tool for detecting raised ICP with accuracy.