Failed spinal anesthesia

Dr. S. Parthasarathy MD., DA., DNB, MD (Acu), Dip. Diab. DCA, Dip.

Software statistics- PhD ( physiology),

( IDRA )

Golden words of 1922

• Two conditions are absolutely necessary to produce spinal anesthesia:

• puncture of the dura mater and subarachnoid injection of an anesthetic agent.

• Gaston Labat• 1922

Define it ?

• Spinal Anesthesia is considered to have failed

if anesthesia and analgesia have not effected

within 10 minutes of successful intrathecal

deposition of heavy bupivacaine and 25

minutes for plain bupivacaine

Only three options ?? Or more !!

Clinical definitions !!

• 1. Not acted at all • 2. Acted but deficient in • a) quantity, • b) Quality or • c) duration ?? • Incidence -- < 1 % some studies 17 % • But acceptable is 3 -4 % in many reviews

Incidence

Incidence

Cant go near !!

• Failed lumbar puncture

• Dry tap ??

• Needle without the stylet – blood tissue clogs

• But not common

Faulty position

• Tip of table • Flexion • Shoulder straight ? • Kyphosis , scoliosis ? Fracture hip• Previous lamina surgery • The sitting is usually an easier option in ‘difficult’

patients, but sometimes the reverse is true. • The role of the assistant !!

Position and adjuncts

• A calm, relaxed patient is more likely to assume and maintain the correct position,

• so explanation (before and during the procedure) • Gentle slow handling• light anxiolytic premedication • local anaesthetic infiltration without obscuring the

landmarks, but must include both intradermal and s.c. injection.

Needle insertion

• Which space ? • Midline , hitting bone • Cephalad • Rarely inferior and lateral • Get the mental picture

• Midline calcification think paramedian

Spinal USG

Pseudo-successful lumbar puncture

• Getting the fluid but not CSF

• Epidural top ups

• Arachnoid cyst

Solution injection errors

• Aspiration • Correct dose • Correct drug

Get the feel !! Or

CSF alone is dripping

Dose selection

• Correct dose – • specific local anaesthetic used• the baricity of that solution• the patient’s subsequent posture, • the type of block intended, • anticipated duration of surgery

• Mass matters

Loss of injectate

• In the needle remains • Luer lock • Movement • Labour pain ? • Back of the other hand • Aspirate but don’t displace

Pencil point needles problems

Pictures from the internet for closed academic purpose only

Inadequate intrathecal spread

• Anatomical changes,• position,• space injected ,• CSF volume

Identification errors

• Which drug is local • Which is test dose • Which is spinal drug

• Confusion ?

Chemical incompatibility

• Clonidine + opioid + LA

• LA + 2 opioids

• LA with ketamine and midazolam

• LA with adrenaline

Not well defined

• The older, ester-type local anesthetics are chemically labile

• heat sterilization and prolonged storage ?? , make them ineffective because of hydrolysis??

• Newer Amides are stable

“Resistance”

• Very rarely a failed spinal anaesthetic has been attributed to physiological ‘resistance’ to the actions of local anaesthetic drugs,

• Sodium channel mutation • Scorpion stings !!

• Anecdotal

This batch is not good !!

• The neuroscience division of AstraZeneca received

562 ‘Product Defect Notification’ reports in the 6

year to December 31, 2007, all ascribing failed spinal

anaesthetics to ineffective bupivacaine solution• But chemical analyses proved everything Ok in

all cases

Failure of subsequent management

• Level – covert pinch – glance of the eyes between surgeons and anaes – yes OK – start

• Abdomen cleaning , mopping – sedatives

• Can we stay in an abnormal position for hours ? – table and position are for surgeons

Injected proper but ??

Tarlov Cyst • Fluid-filled nerve root

valved or nonvalved cysts found most commonly at the sacral level of the spine

• Asymptomatic TC are present in 5-9 %. Female are more frequently affected

• Treatment is drainage of CSF or surgery

High CSF volume

Volume ??

Ballooned dural sac

Can happen !!

• Some pain fibres pass via sympathetic nerve and then via sympathetic chain to reach the spinal cord at higher level than the site of injection and may be the cause of failure.

• Lateral approach -- dural investment of nerve root resulting in false feeling of placement of needle tip in the subarachnoid space

Rapid sequence spinal anesthesia – more likely to fail

• IV access , monitors with staff 1 • Chlorhexidine preparation with staff 2 • No local • Non touch spinal • No additives • A larger dose • Start as the block starts • Be Ready for GA • 5-7 minutes

Non touch spinal by me in 40 seconds

Management of failure

Prevention is better than cure

Clinical and medicolegal!!

• How and when it is found out • Tincture of time 15 minutes • Then alternative arrangement

No block:

• the wrong solution, • the wrong place,• or it is ineffective. • Repeating the procedure or conversion to

general anesthesia • the patient has significant pruritus, - only

opioid injected

Good block but less height

• Flex knees and hips and trendelenberg

• Obstetrics – left and right lateral and head down

Patchy blocks

• This term is used to describe a block that appears adequate in extent, but the sensory and motor effects are incomplete.

• Some sensory and some motor segments spared and quality is not that good.

Repeat – GA – sedation or local infiltration

When we repeat • Excessive repeat dose – need to reduce !• Higher level of injection • Is it not neurotoxic • Anesthetised nerves prone for nerve injuries

• Recourse to an epidural in technical difficulties

• Rescue measures and GA – beware of already existing sympathetic block and hypotension

• Document and explain to patients but avoid medico legal problems

• Look for local hospital problems

Three muskateers

• Right place • Right drug • Right dose

• Decide

• Lumbar puncture

• Local injection

• Spread

• Action on nerves

Failure

Failure

Failure

Failure

abnormalities of the spine, thickened ligamentum flavum,

flexible small spinal needle, and improper positioning of the patient or the inexperience of the person

giving the block.

Leaks , partly outside , wrong drugs ,gauge of needle ,

subdural ,aspirate

Anatomical changes, position, space injected ,CSF volume

Bloody taps, high CSF pH, repeated autoclave. resistance, age, drug

volume, which drug

• Alfred E. Barker wrote that for successful spinal

analgesia

• it is necessary ‘to enter the lumbar dural sac

effectually with the point of the needle, and to

discharge through this, all the contemplated dose of

the drug, directly and freely into the cerebrospinal

fluid, below the termination of the cord’

Feel and give

Failure -Prevention of failure is the most important step

• Preoperative noted – • Assess and assure • Sedate • Drugs which increase• Position, valsalva ,

cough , EVE • Repeat – dose drug !! • GA

• Intraoperative noted • Assess • Assure • Local • Sedate • GA

•Thank you all