Failed spinal anesthesia Dr. S. Parthasarathy MD., DA., DNB, MD (Acu), Dip. Diab. DCA, Dip. Software statistics- PhD ( physiology), ( IDRA )

Golden words of 1922 Gaston Labat 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

Prevention is better than cure 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

Anatomical changes, position, space injected ,CSF volume 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. Decide Lumbar puncture Local injection Spread Action on nerves Failure Failure Leaks , partly outside , wrong drugs ,gauge of needle , subdural ,aspirate Failure Anatomical changes, position, space injected ,CSF volume Failure 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