Journal article
Correlation of optic nerve and optic nerve sheath diameter with intracranial pressure in pigs.
- Mija R Department of Neurosurgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
- Zubak I Department of Neurosurgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
- Schuetz A Department of Neurosurgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
- Glas M Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
- Fung C Department of Neurosurgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
- Jakob SM Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
- Beck J Department of Neurosurgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
- Z'Graggen WJ Department of Neurosurgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
- Bloch A Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
- 2020-02-05
Published in:
- PloS one. - 2020
English
OBJECTIVE
Several studies have shown an association between intracranial pressure and the diameter of the optic nerve sheath measured by transbulbar ultrasonography. To understand the pathophysiology of this phenomenon, we aimed to measure the changes of the optic nerve, optic nerve sheath and perineural space separately with increasing intracranial pressure in a porcine model.
METHODS
An external ventricular drain was placed into the third ventricle through a right paramedian burrhole in eight anesthesized pigs. The diameters of the optic nerve and the optic nerve sheath were measured while the intracranial pressure (ICP) was increased in steps of 10mmHg from baseline up to 60 mmHg.
RESULTS
The median diameters of the optic nerve (ON) increased from 0.36 cm (baseline- 95% confidence interval (CI) 0.33 cm to 0.45 cm) to 0.68 cm (95% CI 0.57 cm to 0.82 cm) at ICP of 60 mmHg (p<0.0001) and optic nerve sheath (ONS) from 0.88 cm (95% CI 0.79 cm to 0.98 cm) to 1.24 cm (95% CI 1.02 cm to 1.38 cm) (p< 0.002) while the median diameter of the perineural space (PNS) (baseline diameter 95% CI 0.40 cm to 0.59 cm to diameters at ICP 60 95% CI 0.38 cm to 0.62 cm) did not change significantly (p = 0.399). Multiple comparisons allowed differentiation between baseline and values ≥40 mmHg for ON (p = 0.017) and between baseline and values ≥ 50mmHg for ONS (p = 0.006). A linear correlation between ON (R2 = 0.513, p<0.0001) and ONS (R2 = 0.364, p<0.0001) with ICP was found. The median coefficient of variation for intra- and inter-investigator variability was 8% respectively 2.3%.
CONCLUSION
Unexpectedly, the increase in ONS diameter with increasing ICP is exclusively related to the increase of the diameter of the ON. Further studies should explore the reasons for this behaviour.
Several studies have shown an association between intracranial pressure and the diameter of the optic nerve sheath measured by transbulbar ultrasonography. To understand the pathophysiology of this phenomenon, we aimed to measure the changes of the optic nerve, optic nerve sheath and perineural space separately with increasing intracranial pressure in a porcine model.
METHODS
An external ventricular drain was placed into the third ventricle through a right paramedian burrhole in eight anesthesized pigs. The diameters of the optic nerve and the optic nerve sheath were measured while the intracranial pressure (ICP) was increased in steps of 10mmHg from baseline up to 60 mmHg.
RESULTS
The median diameters of the optic nerve (ON) increased from 0.36 cm (baseline- 95% confidence interval (CI) 0.33 cm to 0.45 cm) to 0.68 cm (95% CI 0.57 cm to 0.82 cm) at ICP of 60 mmHg (p<0.0001) and optic nerve sheath (ONS) from 0.88 cm (95% CI 0.79 cm to 0.98 cm) to 1.24 cm (95% CI 1.02 cm to 1.38 cm) (p< 0.002) while the median diameter of the perineural space (PNS) (baseline diameter 95% CI 0.40 cm to 0.59 cm to diameters at ICP 60 95% CI 0.38 cm to 0.62 cm) did not change significantly (p = 0.399). Multiple comparisons allowed differentiation between baseline and values ≥40 mmHg for ON (p = 0.017) and between baseline and values ≥ 50mmHg for ONS (p = 0.006). A linear correlation between ON (R2 = 0.513, p<0.0001) and ONS (R2 = 0.364, p<0.0001) with ICP was found. The median coefficient of variation for intra- and inter-investigator variability was 8% respectively 2.3%.
CONCLUSION
Unexpectedly, the increase in ONS diameter with increasing ICP is exclusively related to the increase of the diameter of the ON. Further studies should explore the reasons for this behaviour.
- Language
-
- English
- Open access status
- gold
- Identifiers
-
- DOI 10.1371/journal.pone.0228242
- PMID 32017786
- Persistent URL
- https://sonar.ch/global/documents/178040
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