Evaluation of a modified ultrasound-assisted technique for mid-thoracic epidural placement: a prospective observational study

Table 4 Comparison of different categories based on sonoanatomy on outcomes

Variable	Category I and II ^a (n = 98)	Category III ^b (n = 30)	P value
First-pass success rate ^c	84 (86%)	12 (40%)	<0.001
First-attempt success rate ^d	97 (99%)	25 (83%)	0.003
Overall success rate	98 (100%)	28 (93%)	0.054
Needling time, seconds ^e	57 [44–77]	156 [61–245]	<0.001
Number of needle passes	1 [1–1]	2 [1–3]	<0.001
Number of attempts	1 [1–1]	1 [1–1]	0.011

Data are presented as numbers (percentages) or medians [IQRs].
^a Category I-II indicates that the anterior complex was visible in the paramedian sagittal oblique view
^b Category III indicates that the anterior complex was invisible in both the paramedian sagittal oblique view and transverse median view
^c First-pass success, defined as achievement of LOR and successful catheter placement through a single skin puncture with no needle withdrawal and redirection
^d First-attempt success, defined as the needle achieving LOR and successful catheter placement through a single skin puncture
^e Needling time, defined as the time from epidural needle insertion to successful access of the thoracic epidural space via LOR.

ISSN: 1471-2253