CLINICAL INVESTIGATION
Optic Nerve Sheath Diameter Point-of-Care
Ultrasonography Quality Criteria Checklist:
EIdjqkXFluOr7X8nEfCHm96Cgu9Kl7T/hMCv2coZRn1DjSxT8rMj16rH+9zg3ozUkw5NQx9h2hW1CoeSrnGE+I6B0XrD6k3DxXuj
An International Consensus Statement on
Downloaded from http://journals.lww.com/ccmjournal by IrvSuBlO9JezjNTu8kWYkWnKtJ09aZ2acUYM1SmYM9II9f
Optic Nerve Sheath Diameter Imaging and
Measurement
lLuVYDiGD0T3NunFnGtSL7PcXNKOtyYGLy2A== on 06/05/2024
Mohammad I. Hirzallah, MD,
OBJECTIVES: To standardize optic nerve sheath diameter (ONSD) point-of-care MMSc1,2
ultrasonography (POCUS) and improve its research and clinical utility by devel- Piergiorgio Lochner, MD, PhD3
oping the ONSD POCUS Quality Criteria Checklist (ONSD POCUS QCC).
Muhammad Ubaid Hafeez, MD4
DESIGN: Three rounds of modified Delphi consensus process and three rounds Andrew G. Lee, MD5,6
of asynchronous discussions.
Christos Krogias, MD7
SETTING: Online surveys and anonymous asynchronous discussion. Deepa Dongarwar, MS8
SUBJECTS: Expert panelists were identified according to their expertise in Nicholas D. Hartman, MD, MPH9
ONSD research, publication records, education, and clinical use. A total of 52 Michael Ertl, MD10
panelists participated in the Delphi process.
Chiara Robba, MD, PhD11,12
INTERVENTIONS: None. Branko Malojcic, MD, PhD13
MEASUREMENTS AND MAIN RESULTS: Three Delphi rounds and three Jurgita Valaikiene, MD, PhD14
asynchronous discussion rounds generated consensus on quality criteria (QC). Aarti Sarwal, MD15
This started with 29 QC in addition to other QC proposed by expert panelists. The
Ryan Hakimi, DO, MS16,17
QC items were categorized into probe selection, safety, body position, imaging,
measurement, and research considerations. At the conclusion of the study, 28 Felix Schlachetzki, MD18
QC reached consensus to include in the final ONSD POCUS QCC. These QC for the Optic Nerve Sheath
were then reorganized, edited, and consolidated into 23 QC that were reviewed Diameter Point-of-Care
and approved by the panelists. Ultrasonography Quality Criteria
Checklist (ONSD POCUS QCC)
CONCLUSIONS: ONSD POCUS QCC standardizes ONSD ultrasound im- Expert Panelists
aging and measurement based on international consensus. This can establish
ONSD ultrasound in clinical research and improve its utility in clinical practice.
KEYWORDS: consensus; Delphi; intracranial pressure; optic nerve sheath
diameter; quality criteria; ultrasound
T
he optic nerve sheath (ONS) cerebrospinal fluid (CSF) is a direct con-
tinuation of the subarachnoid space. This makes optic nerve sheath
diameter (ONSD) a promising surrogate of cerebral compliance and in-
tracranial pressure (ICP) (1). Although ONSD obtained by using point-of-care
ultrasonography (POCUS) reliably detected elevated ICP in studies (2, 3) vari-
able diagnostic cutoffs ranging from 4.8 to 6.4mm were found in meta-analyses
(4, 5) limiting its clinical value (6). Variability is also reported in imaging and Copyright © 2024 by the Society of
measurement methods (7, 8). Checklists may improve ONSD measurements Critical Care Medicine and Wolters
(3, 9, 10) but are not widely adopted. The aim of this work is to develop interna- Kluwer Health, Inc. All Rights
tional expert consensus on ONSD imaging, measurement, and research by de- Reserved.
veloping the ONSD POCUS Quality Criteria Checklist (ONSD POCUS QCC). DOI: 10.1097/CCM.0000000000006345
Critical Care Medicine www.ccmjournal.org 1
Copyright © 2024 by the Society of Critical Care Medicine and Wolters Kluwer Health, Inc. All Rights Reserved.
, Hirzallah et al
were edited and revoted on based on feedback, 15 QC
did not reach consensus, and seven new QC were sug-
KEY POINTS gested. Round 2 started with 32 QC, including voting
on five controversial QC. Eighteen QC reached CTI
Question: The purpose of this consensus state- and 14 QC did not reach consensus. Only one QC
EIdjqkXFluOr7X8nEfCHm96Cgu9Kl7T/hMCv2coZRn1DjSxT8rMj16rH+9zg3ozUkw5NQx9h2hW1CoeSrnGE+I6B0XrD6k3DxXuj
ment is to address optic nerve sheath diameter remained controversial, if ONSD internal (ONSDint)
(ONSD) variability in clinical practice and research
Downloaded from http://journals.lww.com/ccmjournal by IrvSuBlO9JezjNTu8kWYkWnKtJ09aZ2acUYM1SmYM9II9f
or ONSD external (ONSDext) should be the standard
by providing widely accepted ONSD Point-of-Care
Ultrasonography Quality Criteria Checklist (ONSD (Fig. 2). This was determined to be an essential QC
POCUS QCC) to standardize ONSD imaging, a priori and panelists shared images and literature
measurement, and research. to support preferred measurement in asynchronous
discussion round. Outcomes were anonymized and
Findings: A checklist with 23 quality criteria reached
lLuVYDiGD0T3NunFnGtSL7PcXNKOtyYGLy2A== on 06/05/2024
consensus by a panel of 50 experts. shared during round 3. At the conclusion of round 3,
23 QC reached CTI and nine did not reach consensus.
Meaning: The ONSD POCUS QCC will help stand- ONSDint vs. ONSDext remained controversial. After
ardize ONSD imaging and measuring enabling
two more asynchronous anonymized discussions
comparability in clinical practice and research.
rounds, the ONSDint vs. ONSDext issue reached CTI
(two QC) in addition to three new related QC sug-
gested by panelists.
METHODS At study conclusion, 28 QC reached CTI. They were
This study was approved by the Baylor College of then reorganized, edited, and consolidated into 23
Medicine Institutional Review Board (IRB) (Protocol: QC that were reviewed and approved by the panelists.
H-51400). It was reviewed and endorsed by the German The ONSD POCUS QCC is presented in Table 1 and
Society of Ultrasound in Medicine, European Society Supplemental table 1 (http://links.lww.com/CCM/
of Neurosonology and Cerebral Hemodynamics, and H554). Fifty panelists completed all rounds and are ac-
American Society of Neuroimaging. The study was knowledged in Table 2.
approved by Baylor College of Medicine IRB. The con-
sensus used a modified Delphi method. The Delphi DISCUSSION
justification, design, informational input, validation,
Probe and Preset Selection
procedure, expert selection criteria, and definition of
consensus were previously published (8). Briefly, a re- Probe.
view of ONSD methods from 357 articles quantified
the sources of variation across six categories: probe 1) A linear probe with a minimum effective
selection, safety, body position, imaging, measure- frequency of 7.5 MHz should be used to obtain
ment, and research considerations then synthesized a ONSD images.
preliminary ONSD POCUS QCC. The Delphi study Linear probes and frequencies of greater than or equal
included ten oversight committee members and 52
to 7 MHz were used in 88.8% and 57.7% of reviewed
international expert panelists. Panelists were selected
articles (8). The minimum frequency needed to detect
based on expertise in ONSD research and publication
ONSD changes is 7.5 MHz (11). This QC was com-
record, education, and clinical use. Panelists voted
bined and modified from two QC per feedback then
using a 5-point Likert scale and agreement to include
reached CTI (mean Likert 4.5, round 2). Panelists sug-
was defined as 70% agreement on importance and a
gested that optimal frequency was 9–12 MHz. Two
mean Likert scale greater than or equal to 4.
panelists withdrew from the study over preference
for A-scan ultrasonography over POCUS. A-scan, or
RESULTS amplitude scan, represents structures as spikes, not
Figure 1 summarizes Delphi process flow. Round 1 images (12) and predates high-frequency B-mode
started with 29 quality criteria (QC), five QC reached probes for optic nerve (ON) imaging (13), there are
consensus to include (CTI), seven QC reached CTI but no studies comparing the two outside expert opinions
2 www.ccmjournal.org XXX 2024 • Volume 52 • Number 00
Copyright © 2024 by the Society of Critical Care Medicine and Wolters Kluwer Health, Inc. All Rights Reserved.
Optic Nerve Sheath Diameter Point-of-Care
Ultrasonography Quality Criteria Checklist:
EIdjqkXFluOr7X8nEfCHm96Cgu9Kl7T/hMCv2coZRn1DjSxT8rMj16rH+9zg3ozUkw5NQx9h2hW1CoeSrnGE+I6B0XrD6k3DxXuj
An International Consensus Statement on
Downloaded from http://journals.lww.com/ccmjournal by IrvSuBlO9JezjNTu8kWYkWnKtJ09aZ2acUYM1SmYM9II9f
Optic Nerve Sheath Diameter Imaging and
Measurement
lLuVYDiGD0T3NunFnGtSL7PcXNKOtyYGLy2A== on 06/05/2024
Mohammad I. Hirzallah, MD,
OBJECTIVES: To standardize optic nerve sheath diameter (ONSD) point-of-care MMSc1,2
ultrasonography (POCUS) and improve its research and clinical utility by devel- Piergiorgio Lochner, MD, PhD3
oping the ONSD POCUS Quality Criteria Checklist (ONSD POCUS QCC).
Muhammad Ubaid Hafeez, MD4
DESIGN: Three rounds of modified Delphi consensus process and three rounds Andrew G. Lee, MD5,6
of asynchronous discussions.
Christos Krogias, MD7
SETTING: Online surveys and anonymous asynchronous discussion. Deepa Dongarwar, MS8
SUBJECTS: Expert panelists were identified according to their expertise in Nicholas D. Hartman, MD, MPH9
ONSD research, publication records, education, and clinical use. A total of 52 Michael Ertl, MD10
panelists participated in the Delphi process.
Chiara Robba, MD, PhD11,12
INTERVENTIONS: None. Branko Malojcic, MD, PhD13
MEASUREMENTS AND MAIN RESULTS: Three Delphi rounds and three Jurgita Valaikiene, MD, PhD14
asynchronous discussion rounds generated consensus on quality criteria (QC). Aarti Sarwal, MD15
This started with 29 QC in addition to other QC proposed by expert panelists. The
Ryan Hakimi, DO, MS16,17
QC items were categorized into probe selection, safety, body position, imaging,
measurement, and research considerations. At the conclusion of the study, 28 Felix Schlachetzki, MD18
QC reached consensus to include in the final ONSD POCUS QCC. These QC for the Optic Nerve Sheath
were then reorganized, edited, and consolidated into 23 QC that were reviewed Diameter Point-of-Care
and approved by the panelists. Ultrasonography Quality Criteria
Checklist (ONSD POCUS QCC)
CONCLUSIONS: ONSD POCUS QCC standardizes ONSD ultrasound im- Expert Panelists
aging and measurement based on international consensus. This can establish
ONSD ultrasound in clinical research and improve its utility in clinical practice.
KEYWORDS: consensus; Delphi; intracranial pressure; optic nerve sheath
diameter; quality criteria; ultrasound
T
he optic nerve sheath (ONS) cerebrospinal fluid (CSF) is a direct con-
tinuation of the subarachnoid space. This makes optic nerve sheath
diameter (ONSD) a promising surrogate of cerebral compliance and in-
tracranial pressure (ICP) (1). Although ONSD obtained by using point-of-care
ultrasonography (POCUS) reliably detected elevated ICP in studies (2, 3) vari-
able diagnostic cutoffs ranging from 4.8 to 6.4mm were found in meta-analyses
(4, 5) limiting its clinical value (6). Variability is also reported in imaging and Copyright © 2024 by the Society of
measurement methods (7, 8). Checklists may improve ONSD measurements Critical Care Medicine and Wolters
(3, 9, 10) but are not widely adopted. The aim of this work is to develop interna- Kluwer Health, Inc. All Rights
tional expert consensus on ONSD imaging, measurement, and research by de- Reserved.
veloping the ONSD POCUS Quality Criteria Checklist (ONSD POCUS QCC). DOI: 10.1097/CCM.0000000000006345
Critical Care Medicine www.ccmjournal.org 1
Copyright © 2024 by the Society of Critical Care Medicine and Wolters Kluwer Health, Inc. All Rights Reserved.
, Hirzallah et al
were edited and revoted on based on feedback, 15 QC
did not reach consensus, and seven new QC were sug-
KEY POINTS gested. Round 2 started with 32 QC, including voting
on five controversial QC. Eighteen QC reached CTI
Question: The purpose of this consensus state- and 14 QC did not reach consensus. Only one QC
EIdjqkXFluOr7X8nEfCHm96Cgu9Kl7T/hMCv2coZRn1DjSxT8rMj16rH+9zg3ozUkw5NQx9h2hW1CoeSrnGE+I6B0XrD6k3DxXuj
ment is to address optic nerve sheath diameter remained controversial, if ONSD internal (ONSDint)
(ONSD) variability in clinical practice and research
Downloaded from http://journals.lww.com/ccmjournal by IrvSuBlO9JezjNTu8kWYkWnKtJ09aZ2acUYM1SmYM9II9f
or ONSD external (ONSDext) should be the standard
by providing widely accepted ONSD Point-of-Care
Ultrasonography Quality Criteria Checklist (ONSD (Fig. 2). This was determined to be an essential QC
POCUS QCC) to standardize ONSD imaging, a priori and panelists shared images and literature
measurement, and research. to support preferred measurement in asynchronous
discussion round. Outcomes were anonymized and
Findings: A checklist with 23 quality criteria reached
lLuVYDiGD0T3NunFnGtSL7PcXNKOtyYGLy2A== on 06/05/2024
consensus by a panel of 50 experts. shared during round 3. At the conclusion of round 3,
23 QC reached CTI and nine did not reach consensus.
Meaning: The ONSD POCUS QCC will help stand- ONSDint vs. ONSDext remained controversial. After
ardize ONSD imaging and measuring enabling
two more asynchronous anonymized discussions
comparability in clinical practice and research.
rounds, the ONSDint vs. ONSDext issue reached CTI
(two QC) in addition to three new related QC sug-
gested by panelists.
METHODS At study conclusion, 28 QC reached CTI. They were
This study was approved by the Baylor College of then reorganized, edited, and consolidated into 23
Medicine Institutional Review Board (IRB) (Protocol: QC that were reviewed and approved by the panelists.
H-51400). It was reviewed and endorsed by the German The ONSD POCUS QCC is presented in Table 1 and
Society of Ultrasound in Medicine, European Society Supplemental table 1 (http://links.lww.com/CCM/
of Neurosonology and Cerebral Hemodynamics, and H554). Fifty panelists completed all rounds and are ac-
American Society of Neuroimaging. The study was knowledged in Table 2.
approved by Baylor College of Medicine IRB. The con-
sensus used a modified Delphi method. The Delphi DISCUSSION
justification, design, informational input, validation,
Probe and Preset Selection
procedure, expert selection criteria, and definition of
consensus were previously published (8). Briefly, a re- Probe.
view of ONSD methods from 357 articles quantified
the sources of variation across six categories: probe 1) A linear probe with a minimum effective
selection, safety, body position, imaging, measure- frequency of 7.5 MHz should be used to obtain
ment, and research considerations then synthesized a ONSD images.
preliminary ONSD POCUS QCC. The Delphi study Linear probes and frequencies of greater than or equal
included ten oversight committee members and 52
to 7 MHz were used in 88.8% and 57.7% of reviewed
international expert panelists. Panelists were selected
articles (8). The minimum frequency needed to detect
based on expertise in ONSD research and publication
ONSD changes is 7.5 MHz (11). This QC was com-
record, education, and clinical use. Panelists voted
bined and modified from two QC per feedback then
using a 5-point Likert scale and agreement to include
reached CTI (mean Likert 4.5, round 2). Panelists sug-
was defined as 70% agreement on importance and a
gested that optimal frequency was 9–12 MHz. Two
mean Likert scale greater than or equal to 4.
panelists withdrew from the study over preference
for A-scan ultrasonography over POCUS. A-scan, or
RESULTS amplitude scan, represents structures as spikes, not
Figure 1 summarizes Delphi process flow. Round 1 images (12) and predates high-frequency B-mode
started with 29 quality criteria (QC), five QC reached probes for optic nerve (ON) imaging (13), there are
consensus to include (CTI), seven QC reached CTI but no studies comparing the two outside expert opinions
2 www.ccmjournal.org XXX 2024 • Volume 52 • Number 00
Copyright © 2024 by the Society of Critical Care Medicine and Wolters Kluwer Health, Inc. All Rights Reserved.
