COMPLICATIONS OF REGIONAL TECHNIQUES IN OBSTETRICS

Dr.Sreejith.H

Regional anaesthesia is a safe and widely utilised method of analgesia for labour.

The majority of caesarean sections are managed using spinal (intrathecal), epidural or combined spinal / epidural (CSE) techniques.

Although serious complications are uncommon with regional anaesthesia, they must be considered and should be discussed with the patient.

Over 100 years ago August Bier performed the first recorded spinal anaesthetic

complications from the use of regional anaesthesia have been described over this same period of time

Bier also being the first to describe a ‘spinal’ or ‘post dural-puncture headache’

In 1950’s decline in use of neuraxial technique due its complications

over the last thirty years the increased use of regional anaesthesia for caesarean section due to its increased safety

General anaesthesia is now used in less than 5% of caesarean sections

There are still a number of important complications that are associated with regional anaesthesia and analgesia

COMPLICATIONS OF NEURAXIAL ANAESTHESIA

Adverse or exagerrated physiological responses

Complications Related To Needle/ Catheter Placement

Drug Toxicity

ADVERSE OR EXAGERRATED PHYSIOLOGICAL RESPONSES

Urinary retention High block Total spinal anesthesia Cardiac arrest Anterior spinal artery syndrome Horner's syndrome

COMPLICATIONS RELATED TO NEEDLE/CATHETER PLACEMENT

Trauma Backache Dural puncture/leak Postdural puncture headache Diplopia Tinnitus Neural injury Nerve root damage Spinal cord damage Cauda equina syndrome Bleeding Intraspinal/epidural hematoma

Misplacement No effect/inadequate anesthesia Subdural block Inadvertent subarachnoid block1 Inadvertent intravascular injection Catheter shearing/retention Inflammation Arachnoiditis Infection Meningitis Epidural abscess

DRUG TOXICITY

Systemic local anaesthetic toxicity Transient Neurological Symptoms Cauda Equina Syndrome

HYPOTENSION

Defined as a 20-30% decrease in systolic BP or systolic BP less than 100 mm Hg

Occurs due to sympathetic blockade leading to vasodilatation

Aorto-caval compression Incidence & severity depends on Height of block Position of parturient Whether prophylatic measurements taken to avoid such hypotension

Measures to decrease risk of Hypotension

Intravenous administration of fluids Avoidance of aorto caval compression Vigilant monitoring of BP at frequent intervals Uterine blood flow is directly dependant

on maternal blood pressure FHR evaluation is helpful

Treatment Administration of iv crystalloids Placement of mother in full lateral

position Administration of supplimental oxygen Incremental dose of ephedrine(5-10

mg)Why phenylepherine?

BRADYCARDIA

Most commonly after spinal anaesthesia

May progress to Complete heart block or asystole

Caused by blockade of preganglionic cardiac accelerator fibers (T1-T4)

Decrease in venous return leading to decrease action of right atrial stretch receptors

Usually responds to iv atropine

ACCIDENTAL DURAL PUNCTURE

Common & problematic complication of epidural placement

Incidence upto 3% Can lead PDPH upto 70% cases May be detected at the time of insertion of

epidural needle or after placement of the catheter Management is to remove the needle & reposition

the catheter at a different interspace Placement of a catheter in the subarachnoid

space to become a continuous spinal technique

SPINAL HEADCHE CAN BE REDUCED BY

Injection of CSF from the epidural syringe back into the subarachnoid space through needle

Insertion of an epidural catheter into subarachnoid space

Injection of preservative free NS through intrathecal catheter beforeits removal

Adminstration of continuous intrathecal labor analgesia

Leaving the intrathecal catheter insitu for a total of 12 to 20 hrs

POST DURAL PUNCTURE HEADACHE(PDPH)

Incidence :0.5-2% for spinal 1-7.6% for epidural PDPH has typical feature of postural headche

that is worsened by standing / staining &relieved by lying down

Aetiology Due to CSF leaking through dural puncture site, leading to intracranial hypotension. This causes settling of brain & strecthing of intracranial nerves, meninges,blood vessels

DIAGNOSIS

Severe , disabling fronto-occipital headache with radiation to the neck & shoulders

Presents 12 hrs or more after dural puncture Worsens on sitting & standing ,relieved by

lying down & abdominal compression May be associated photophobia, vertigo,

nausea & vomiting, diplopia, hearing loss, tinnitus. Convulsions & visual field efects

DIFFERENTIAL DIAGNOSIS

Eclampsia , migraine, tension headache , pneumocephalus

Infections including sinusitis& meningitis

Cortical vein thrombosis & saggital sinus thrombosis

Hypertensive encephalopathy Subdural haematoma

MANAGEMENT OF PDPH

Conservative Bedrest Encourage oral fluids & or intravenous

hydration Caffeine – either iv (eg: 500 mg

caffeine in 1 litre saline) or orally Regular analgesia Reassurance

Interventional - Epidural patch First described more than 40 yrs ago Most effective treatment of PDPH Injecting 20 ml of patient’s own blood into

epidural space near puncture site Form a clot obstructing dural tear Causes increase in CSF pressure & cerebral

vasoconstriction Success rate only 61 %

TOTAL SPINAL BLOCK

After excessive cephalic spread of local anaesthetic

Can occur during single shot spinal anasthesia Inadvertent intrathecal spread of epidural

medication after unintentional dural puncture or catheter migration

Subdural spread of local anaesthetic can also cause a high block characterised by

high sensory level sacral sparing incomplete / absent motor block

Symptoms Hypotension Dyspnoea Inability to speak & loss of

consciousness Numbness or weakness of hand Nasal mucosa become engorged

INTRAVASCULAR INJECTION OF LOCAL ANAESTHETIC

CNS symptoms : restlessness,diziness,tinnitus,perioral parasthesia, difficulty in speaking, seizures, loss of conciousnessCARDIOVASCULAR EFFECTS May progress from increased blood pressure to

bradycardia, Depressed ventricular function & ventricular

tachycardia and fibrillationMATERNAL CONVULSION were the single most common untoward event

INADEQUATE ANALGESIA

Failure rate of epidural analgesia ranges from 1.5% to 5 % depending on the skill of the anaesthetist

NEUROLOGIC COMPLICATIONS

Direct trauma to spinal cord is very rare Nerve root trauma Cauda equina syndrome / adhesive

arachnoiditis are due to chemical toxicity

Thrombosis of anterior spinal artery may lead to motor weakness or paralysis & loss of pain & temparature sensation

CENTRAL NERVOUS SYSTEM INFECTIONS

Infection may be exogenous in origin caused by contamination of equipment or pharmacologicalic agents or by colonisation of catheter

Endogenous spread may occur from a site of infection elsewhere in the body

Epidural abscess 1 in 10000 cases Fever , backpain, localized infection at the level of

epidural site 2 to 3 days after procedureMeningitis may be associated with bacteraemia

SPINAL & EPIDURAL HAEMATOMAIncidence 1 in 150000 for epidural 1 in 220000 for spinalRisk Factors Low platelet count INR level above 1.4 Use of anticoagulants & thromboprophylaxis with

LMWHRecent guidelines is to defer regional technique 10- 12 hrs in a parturient who has received preoperative LMWH OR 24 hrs for those receiving higher dose of LMWH

BACKACHE

Low backache is common after delivery 3-45 % women receiving epidural 40% for spontaneous vaginal delivery 25% for instrumantal deliveryFactors which may predispose for increase incidence in epidural Use of larger needle Supraspinous ligament haematoma Difficult identification of epidural space Prolonged assumption of a unnatural position during

labor or delivery Sacroilaiac strain

TRANSIENT NEUROLOGICAL SYMPTOMS First described in 1993 Also known as transient radicular irritation Characterized by backpain radiating to the legs

without sensory or motor deficits Occuring after resolution of spinal block & resolving

spontaneously within several days Most commonly seen with HYPERBARIC

LIDOCAINE(11.9%) Also reported with

tetracaine(1.6%),bupivacaine(1.3%),mepivacaine , prilocaine,procaine,ropivaciane

Incidence is highest among outpatients(early ambulation) after surgery in the lithotomy position & lowest among inpatients in positions other than lithotomy

Pathogenesis is believed to represent concentration dependant neurotoxicity of local anaesthetics

URINARY RETENTION

Role of epidural analgesia in urinary retention is unclear

Obstetric factors Long labor Edema Instrumental delivery Perineal trauma Haematoma pain

NAUSEA & VOMITING

Is usually associated with hypotension due to spinal blockade

Responds to treating of hypotension May be also due surgical stimuli such

as traction of peritoneum Associated with use of opioids

EFFECTS ON 2ND STAGE OF LABOR & CAESAREAN SECTION

Mainly two controversies Whether it prolongs 2nd stage of labor? Whether it increases the need of

operative delivery?Strong local anasethetic solution with high motor blockade compromises parturient’s ability to actively push