NOTE: Identification of fluid as saline still requires use of aspiration testing and use of a test dose of the local anesthetic.
Protocol:
(1) The patient is in the left lateral position.
(2) The epidural space is identified by a loss of resistance to saline ("loss of resistance technique").
(3) 10 mL of saline is injected into the epidural space.
(4) 0.2 to 1.0 mL of saline was withdrawn into a 2 mL syringe.
(5) If no saline could be withdrawn then an additional 5 mL of saline was injected, then step 4 repeated.
Parameters:
(1) temperature of withdrawn fluid (using the back of a gloved hand)
(2) glucose concentration on a urine dipstick
(3) protein concentration on a urine dipstick
(4) pH
|
Parameter
|
Finding
|
Points
|
|
temperature of withdrawn fluid
|
cold
|
0
|
|
|
warm
|
1
|
|
glucose
|
none
|
0
|
|
|
present (any)
|
1
|
|
protein
|
none
|
0
|
|
|
present (any)
|
1
|
|
pH
|
<= 7.0
|
0
|
|
|
>= 7.5
|
1
|
total score =
= SUM(points for all 4 parameters)
Interpretation:
• minimum score: 0
• maximum score: 4
• The higher the score the more likely that the fluid is cerebrospinal fluid.
• The lower the score the more likely that the fluid is saline.
|
Total Score
|
Interpretation
|
|
0 or 1
|
saline
|
|
2
|
indeterminate
|
|
3 or 4
|
CSF
|
Factors affecting results:
(1) temperature of the saline prior to injection
(2) length of time saline is left in place (the longer it is in place, the warmer it will be)
(3) initial pH of the saline
