TY - JOUR
T1 - The Effects of Acute Intracranial Pressure Changes on the Episcleral Venous Pressure, Retinal Vein Diameter and Intraocular Pressure in a Pig Model
AU - Ghate, Deepta
AU - Kedar, Sachin
AU - Havens, Shane
AU - Fan, Shan
AU - Thorell, William
AU - Nelson, Carl
AU - Gu, Linxia
AU - Tong, Junfei
AU - Gulati, Vikas
N1 - Publisher Copyright:
© 2020 The Author(s). Published with license by Taylor & Francis Group, LLC.
PY - 2021
Y1 - 2021
N2 - Purpose: Orbital veins such as the retinal veins and episcleral veins drain into the cavernous sinus, an intracranial venous structure. We studied the effects of acute intracranial pressure (ICP) elevation on episcleral venous pressure, intraocular pressure and retinal vein diameter in an established non-survival pig model. Methods: In six adult female domestic pigs, we increased ICP in 5 mm Hg increments using saline infusion through a lumbar drain. We measured ICP (using parenchymal pressure monitor), intraocular pressure (using pneumatonometer), episcleral venous pressure (using venomanometer), retinal vein diameter (using OCT images) and arterial blood pressure at each stable ICP increment. The average baseline ICP was 5.4 mm Hg (range 1.5–9 mm Hg) and the maximum stable ICP ranged from 18 to 40 mm Hg. Linear mixed models with random intercepts were used to evaluate the effect of acute ICP increase on outcome variables. Results: With acute ICP elevation, we found loss of retinal venous pulsation and increased episcleral venous pressure, intraocular pressure and retinal vein pressure in all animals. Specifically, acute ICP increase was significantly associated with episcleral venous pressure (β = 0.31; 95% CI 0.14–0.48, p < .001), intraocular pressure (β = 0.37, 95%CI 0.24–0.50; p < .001) and retinal vein diameter (β = 11.29, 95%CI 1.57–21.00; p = .03) after controlling for the effects of arterial blood pressure. Conclusion: We believe that the ophthalmic effects of acute ICP elevation are mediated by increased intracranial venous pressure producing upstream pressure changes within the orbital and retinal veins. These results offer exciting possibilities for the development of non-invasive ophthalmic biomarkers to estimate acute ICP elevations following significant neuro-trauma.
AB - Purpose: Orbital veins such as the retinal veins and episcleral veins drain into the cavernous sinus, an intracranial venous structure. We studied the effects of acute intracranial pressure (ICP) elevation on episcleral venous pressure, intraocular pressure and retinal vein diameter in an established non-survival pig model. Methods: In six adult female domestic pigs, we increased ICP in 5 mm Hg increments using saline infusion through a lumbar drain. We measured ICP (using parenchymal pressure monitor), intraocular pressure (using pneumatonometer), episcleral venous pressure (using venomanometer), retinal vein diameter (using OCT images) and arterial blood pressure at each stable ICP increment. The average baseline ICP was 5.4 mm Hg (range 1.5–9 mm Hg) and the maximum stable ICP ranged from 18 to 40 mm Hg. Linear mixed models with random intercepts were used to evaluate the effect of acute ICP increase on outcome variables. Results: With acute ICP elevation, we found loss of retinal venous pulsation and increased episcleral venous pressure, intraocular pressure and retinal vein pressure in all animals. Specifically, acute ICP increase was significantly associated with episcleral venous pressure (β = 0.31; 95% CI 0.14–0.48, p < .001), intraocular pressure (β = 0.37, 95%CI 0.24–0.50; p < .001) and retinal vein diameter (β = 11.29, 95%CI 1.57–21.00; p = .03) after controlling for the effects of arterial blood pressure. Conclusion: We believe that the ophthalmic effects of acute ICP elevation are mediated by increased intracranial venous pressure producing upstream pressure changes within the orbital and retinal veins. These results offer exciting possibilities for the development of non-invasive ophthalmic biomarkers to estimate acute ICP elevations following significant neuro-trauma.
KW - Episcleral venous pressure
KW - biomarker
KW - intracranial pressure
KW - intraocular pressure
KW - retinal vein diameter
UR - http://www.scopus.com/inward/record.url?scp=85089552737&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85089552737&partnerID=8YFLogxK
U2 - 10.1080/02713683.2020.1805769
DO - 10.1080/02713683.2020.1805769
M3 - Article
C2 - 32806985
AN - SCOPUS:85089552737
SN - 0271-3683
VL - 46
SP - 524
EP - 531
JO - Current Eye Research
JF - Current Eye Research
IS - 4
ER -