Bedside ultrasonography of optic nerve sheath diameter for detection of raised intracranial pressure in nontraumatic neuro-critically ill patients

Table 1 Patient comorbidities and clinical features on admission

	Variables	Overall (n = 114), %	Normal ONSD (n = 69), %	Raised ONSD (n = 45), %	P value
Comorbidities	Hypertension	54 (47.8)	37 (68.5)	17 (31.5)	0.083
	T2DM	35 (31.0)	21 (60.0)	14 (40.0)	0.979
	CKD	20 (17.7)	14 (70.0)	6 (30.0)	0.323
	CAD	10 (8.8)	4 (40.0)	6 (60.0)	0.193
	OAD	8 (7.1)	7 (87.5)	1 (12.5)	0.142
	Malignancy	7 (15.0)	12 (70.6)	5 (29.4)	0.341
	Others	30 (26.5)	19 (63.3)	11 (36.7)	0.680
	No comorbidities	26 (23.0)	12 (46.2)	14 (53.8)	0.096
Symptoms on admission	Headache	30 (26.5)	18 (60.0)	12 (40.0)	0.982
	Vomiting	19 (16.8)	12 (63.2)	7 (36.8)	0.771
	Blurring of vision	10 (8.8)	4 (40.0)	6 (60.0)	0.193
	Seizures	30 (26.5)	18 (60.0)	12 (40.0)	0.982
	Altered sensorium	103 (91.2)	60 (58.3)	43 (41.7)	0.311
General examination	GCS, mean ± SD	9.39 ± 4.09	10.21 ± 3.97	8.16 ± 3.99	0.009a
	Bradycardia	34 (30.1)	18 (52.9)	16 (47.1)	0.303
	Hypertension	31 (27.4)	19 (61.3)	12 (38.7)	0.882
	Neck stiffness	33 (29.2)	20 (60.6)	13 (39.4)	0.952
	Focal neurological deficit	70 (61.9)	41 (58.6)	29 (41.4)	0.656

^aDenotes Statistical significance

CAD: Coronary artery disease; CKD: Chronic kidney disease; GCS: Glasgow coma scale; OAD: Obstructive airway disease; SD: Standard deviation; T2DM: Type 2 diabetes mellitus.

Table 2 Accuracy of optic nerve sheath diameter at cut-off of 5.7 mm with raised raised intracranial pressure on brain imaging

	Values	95%CI
Sensitivity	77.55	63.38-88.23
Specificity	89.06	78.75-95.49
Positive likelihood ratio	7.09	3.47-14.50
Negative likelihood ratio	0.25	0.15-0.43
Disease prevalence	43.36	34.07-53.01
Positive predictive value	84.44	72.64-91.73
Negative predictive value	83.82	75.36-89.78
Accuracy	84.07	76.00-90.28

Table 3 Hospital course across normal and raised optic nerve sheath diameter groups

		Overall (n = 114)	Normal ONSD (n = 69)	Raised ONSD (n = 45)	P value
Hospital course	SOFA, median [IQR]	5 [3-8]	5 [3-8]	5 [3-8]	0.409
	APACHE II score, median [IQR]	20 [14-26]	21 [14-26]	20 [14-26]	0.569
	Hospital LOS, median [IQR]	17 [7-27.5]	15 [7-28]	18 [8-25]	0.688
	ICU LOS, median [IQR]	10 [5-21]	10 [5-20]	10 [5-21]	0.609
Surgical intervention	Yes	11 (9.7)	2 (18.2)	9 (81.8)	0.0061
	No	102 (90.3)	66 (64.7)	36 (35.3)
Discharged or Death	Discharged	64 (56.6)	41 (64.1)	23 (35.9)	0.335
	Death	49 (43.4)	27 (55.1)	22 (44.9)

¹Denotes statistical significance.

APACHE: Acute physiology and chronic health evaluation; IQR: Inter quartile range; LOS: Length of stay; ONSD: Optic nerve sheath diameter; SOFA: Sequential organ failure assessment.