Skip to Main Content

Chapter 59: Intrathecal Catheter

Idris Mohammed; Yunping Li

BACKGROUND

Intrathecal (IT) catheters, also known as continuous spinal anesthesia, are a reliable and effective neuraxial technique.1 Except in select cases, an intentional IT catheter is not recommended for labor analgesia due to the potential risks of high/total spinal anesthesia or devastating medication errors (Chapter 60, “High Spinal”).2 Here, the chapter focuses on the strategy and management of unintentional IT catheters in obstetric patients (Fig. 59-1).

FIGURE 59-1

Strategy and management of unintentional intrathecal catheter. IT, intrathecal; PCEA, patient-controlled epidural analgesia.

A flowchart shows the strategy and management of ununtentional intrathecal catheter. The flowchart begins with ‘An unintentional dural puncture (UDP) with a large bore epidural needle.’ This leads to two types of placement. The first type is Easy placement. The first text box below this reads as follows: Repeat the placement in another space. Pros: Avoid intrathecal catheters. Cons: Epidural medicines can cross dural puncture and result in high spinal, especially during conversion to anesthesia for cesarean delivery. Once it is done, notify the team. Upon notifying the team, provide management. The text box titled Management lists the following: Proceed with test dose and routine epidural infusion. Check the level often. May need to decrease the epidural infusion rate if the level is too high. For cesarean delivery, bolus epidural carefully. The second type is Difficult placement. The text box below this reads as follows: Insert an epidural catheter 4 to 5 centimeters into subarachnoid space. Perform aspiration and consider checking a glucose test to confirm the IT catheter. No test dose, if confirmed IT catheter. Label “IT Catheter” EVERYWHERE: the catheter, epidural pump, and the whiteboard. Upon notifying the team, provide management. The text box titled ‘Management for Cesarean delivery’ lists the following: Bolus 1.5 milliliters (1 milliliter for the dead space in the filter and catheter) of 0.75 percent hyperbaric bupivacaine first and check level. Then bolus fentanyl 25 micrograms and morphine 0.15 to 0.25 milligrams. Titrate in small doses of 0.75 percent bupivacaine to achieve T4 level. The next text box titled ‘Management for labor’ reads the following: Start IT catheter infusion with the regular epidural solution at 3 to 4 milliliters per hour. May administer a bolus of 2 milliliters from the pump for breakthrough pain. Disable the PCEA function on the pump. Check sensory and motor level q1h. Adjust the epidural infusion rate according to the level.
View Full Size||Download Slide (.ppt)

POTENTIAL INDICATIONS FOR IT CATHETER

Consider insert an IT catheter after an unintentional dural puncture with a large bore epidural needle in the following scenarios:

  • Difficult placement (multiple attempts, morbid obesity, marked scoliosis, history of back surgery potentially affecting the epidural space)

  • Inability to position

  • Near delivery

  • Non-reassuring fetal heart rate tracing

SAFETY PRECAUTIONS FOR IT CATHETERS

To ensure safety when working with an IT catheter, please pay attention to:

  • Label the IT catheter and inform the anesthesia team, the nurse, and the obstetrician.

  • Use the filter for the administration of medications.

  • Suggest using local anesthetic and opioid at low concentrations for IT catheter infusion.

  • Check sensory and motor blockage diligently and adjust the IT infusion rate accordingly.

IDENTIFICATION OF MISPLACED EPIDURAL CATHETERS

Failure to identify an IT catheter can lead to a dangerously high spinal level or total spinal. This can lead to hypotension and poor perfusion of the fetus or emergent intubation outside the operating room and possible maternal aspiration. The importance of careful aspiration of an epidural catheter and performing a test dose cannot be overemphasized (Chapter 40, “Test Dose”). When managing an epidural catheter, consider every bolus as a test dose.

On rare occasions, an epidural catheter can be freely aspirated after prolonged infusion. The differential for this can be elicited from a glucose test and a physical exam. If the glucose test is positive, this may be explained by the catheter being placed in Tarlov cyst. If the glucose test is negative, this may represent the local accumulation of epidural solution—further aspiration attempts are typically negative. In physical exam, the patient usually lacks dense motor block in low extremities.

The differential diagnosis of IT catheter is summarized in Table 59-1.

TABLE 59-1Characteristics of Intrathecal, Subdural, and Epidural Catheters
View Table||Download (.pdf)
TABLE 59-1 Characteristics of Intrathecal, Subdural, and Epidural Catheters

Intrathecal

Subdural

Epidural

Aspiration of CSF

Yes

No

No

Test Dose

Dense sensory and motor block

Extensive spread (may involve the cranial nerves)

Limited spread

CSF Glucose

Positive

Negative

Negative

Onset

Fast and bilateral

Slow and ...

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.

This site uses cookies to provide, maintain and improve your experience. MH Privacy Center Close