Spinals and Epidurals

▪General Information

Spinal Needles

Quincke: Cutting needle; end injection.
Whitacre: Pencil point rounded; side injxn; decr incidence of PDSH.
Sprotte: Long opening at end; side injxn; increases turbulence in CSF.

Epidural Needle

Tuohy: Epidural “introducer”; thread catheter thru Tuohy.

The blunt tip helps push the dura away (after passing through the ligamentum flavum) instead of cutting it.

Test Dose

Detects both intrathecal and intravascular injection.

Combination of LA and epi: Classic test dose: 1.5% Lido with 1:200,000 epinephrine.

This 45 mg Lido (3 cc of 1.5%) will produce spinal anesthesia that is rapidly apparent. The 15 mcg of epi, if enters bloodstream, will increase HR > 20%.

False +: Pain

False −: Pt on beta-blockers

α-Adrenergic Agonists

Clonidine and dexmedetomidine produce analgesia through supraspinal and spinal receptors; enhances intrathecal and epidural anesthesia, PNB, and IV regional without toxicity.

Always volume preload before placing spinal or epidural block, and treat the first signs of hypotension (usually nausea) aggressively.

Absorption

IV > tracheal > intercostal > paracervical > caudal > lumbar epidural > brachial plexus > sciatic > topical > subQ

Plasma Concentration of Local Anesthetic and Effects

1-5 mcg/mL: Analgesia
5-10 mcg/mL: Lightheaded, tongue numb, tinnitus, muscle twitch
10-15 mcg/mL: Seizures, unconscious
15-25 mcg/mL: Coma, resp arrest
> 25 mcg/mL: CV Depression

Excitatory precedes depression.

S/S with asleep pt: 1st s/s heart arrhythmia/collapse Awake pt: CNS s/s

▪Neuraxial Charting Examples

Epidural

To OR; monitors on; pt placed in ___ position.

Landmarks ID’d; pt prepped and draped per sterile technique.

2% lido skin wheal injected @ ___ space; Tuohy needle inserted.

– CSF; – blood.

Epidural; catheter easily inserted ___cm to epidural space.

Test dose of 3 cc 1.5% lido with epi 1:200,000 given, response ___.

Catheter secured; Opsite^® placed; block confirmed to ___ level.

Spinal

To OR; monitors on; pt placed in ___ position.

Landmarks ID’d; pt prepped and draped per sterile technique.

2% lido skin wheal injected @ L ___ space; introducer needle anchored at interspinous ligament. 25 g Whitacre or Sprotte needle inserted into SA space.

+ CSF; – blood; – paresthesia; syringe attached; aspirated; + swirl of CSF.

___ mg of [LA] with ___ mcg fentanyl injected; aspirated; – blood.

Needle removed; band-aid placed.

Block confirmed to ___ level.

Opioids

LA with opioids produces effect greater than with either agent used alone. Epidural/intrathecal opioids bind to receptors in dorsal horn of spinal cord, specifically the substantia gelatinosa. It contains mu, delta and kappa receptors.

Lipophilic opioids (i.e., Fentanyl, Sufentanil) tend to stay in a local, segmental pattern due to spread of drug to fatty tissues surrounding spinal cord.

Morphine, a hydrophilic agent, is retained in the CSF and spreads upward to respiratory centers of medulla. Morphine tends to have a slower onset of analgesia and a prolonged duration; it also has
a delayed respiratory depression. Dosages and usage of epidural/spinal narcotics vary among institutions.

Epidural Opioids

Morphine 3-5 mg; q 6-18 hrs
Fentanyl 50-100 mcg; q 4 hrs

Intrathecal Opioids

Morphine 0.10-0.25 mg; q 12-24 hr
Fentanyl 10-25 mcg; q 2 hr
Sufentanil 5-10 mcg; q 2 hr

▪Spinal Block

Dose and Duration of Spinal Drugs

		Doses			Duration
Drug	Prep	Perineum Lower Limbs	Lower Abdomen	Upper Abdomen	Plain (min)	Epi (min)
Procaine	10% sol	75 mg	125 mg	200 mg	45	60
Bupivacaine	0.75% in 8.25% dextrose	4-10 mg 0.5-1.3 cc	12-14 mg	12-18 mg	90-120	100-150
Tetracaine	1% in 10% glucose	4-8 mg	10-12 mg	10-16 mg	90-120	120-240
Lidocaine	5% in 7.5% glucose	25-50 mg 5-10 cc	50-75 mg	75-100 mg	45-90	75-100
Ropivacaine	0.2%-1% sol	8-12 mg	12-16 mg	16-18 mg	90-120	90-120
Technique: Landmarks: superior iliac crests at L4; lido 1% 2 cc skin wheal; introducer 17 gu to flavum; spinal wire on hub choice needle until CSF seen. Aspirate CSF, slowly inject LA; aspirate before and after each 3-5 cc injectate.