morbidity review by noorfarahnaduwah nurdin supervisor dr tuan norizan

Morbidity review

By Noorfarahnaduwah Nurdin

Supervisor Dr Tuan Norizan

•Madam F, G2 P0+1•No known medical illness•Height 151cm, weight 80kg, BMI 35.09

•Admitted to labour room at 9pm▫Os 3cm, contraction 2:10

•Was referred for epidural anaesthesia

Upon review @ 1am•Patient was on entonox•Bp 130/68 mmhg, pr 90/min•Epidural inserted at level L3L4•Anchored at 10cm•Skin to space 5cm•Test dose 3mls lignocaine 2%•Loading dose 8 mls 0.2% ropi + 50mcg

fentanyl•Started on infusion ropi 0.1% + 2mcg/ml

fentanyl 6mls/hr

5.00 am

Pain score 7-8/10 Increase infusion 13 mls/hr

3.00 am

Pain score 7-8/10Increase infusion 10 mls/hr + bolus 3 mls

lignocaine 2%

1.30 am

Pain score 7-8/10 Increase infusion 8 mls/hr

10.45 am

Posted for EMLSCS for fetal distress

10.30 am

Pain score 7-8/10 Bolus 3 mls ropi 0.2% + cont infusion 13 ms/hr

7.30 am

Pain score 7-8/10 Bolus 3 mls ropi 0.2% + cont infusion 13 ms/hr

In OT•Epidural was removed •Spinal anaesthesia was given at level L3L4▫Heavy marcaine 0.5% + morphine 0.1mg

+ fentanyl 20mcg (total volume 2.2mls)

•About 4 minutes after spinal, complaint of perioral & upper limbs numbness

•Bp dropped down to 70/40mmhg -> responded with phenylephrine

In OT•Spo2 dropped to 88-90%•Also complaint of difficulty in breathing•GCS 15/15•Converted to GA•Intubated with RSI technique

▫STP 250mg▫Scoline 100mg▫CL 1

•bp prior to intubation 120/57mmhg, pr 118/min

Intraoperative•Uterus on/off atony•Resuscitated with

▫1 pint gela▫1 pint sterofundin▫3 pints hartmann

•Other meds▫iv pitocin 10u▫Im ergometrine 0.5mg▫Im hemabate 250 mcg▫Iv morphine 3mg▫Iv pitocin infusion 40u

•EBL 1.4L

Post operative •Transferred to ICU for weaning•Hemodinamically not on inotropes•Extubated upon arrival to ICU

Issues •Inadequate epidural in labour as pain relief

•How to manage patient with epidural proceed with emergency c-sec▫Choices of drugs & doses

•Non functioning epidural in patient proceed with emergency c-sec▫Role of spinal, CSE & GA

Managing failed epidural analgesia for labour

•Failed?▫Partial block▫Unilateral block ▫Patchy block▫Inadequate block

Principle of management

•Understand causes & factors predictive of failed epidural

•Understand why functioning epidural catheter for labour becomes non-functional for c-sec

•Enumerate approaches to manage failed epidural for labour analgesia & operative delivery

•Recognize possible consequences of spinal anaesthesia following failed epidural block

Causes of failed

analgesia

Anatomical factors

Technique, methodology & equipment-

related factors

Initial catheter

misplacement

Catheter migration & malfunction

Catheter malfunction &

defect

Patient-related & other risk

factors

Technical skills/performance factors

Anatomical factors•Presence of midline epidural band/connective

tissue -> difficult to thread epidural catheter through Touhy needle -> coiling catheter during introduction

•> lumbar lordosis -> decrease intervertebral space

•Ligamentum flavum ‘softer’ & less dense due to hormonal changes & edema

•Difficulty blocking larger spinal nerve root e.g: sacral nerve root (17.53% failure rate)

Technique, methodology & equipment-related factors

1. Initial catheter misplacement ▫ Accidental transforaminal passage▫ Migration of catheter into anterior

epidural space▫ Unintended placement of catheter in

paravertebral space

*increased distance from skin to space correlates to higher incidence of unilateral block


2. Catheter migration & malfunction

▫ Up to 50% catheters migrate during labour.

▫ Greatest change in position occur in

BMI >30; change position from sitting to supine


3. Catheter malfunction & defects▫ Catheter knotting/kinking, blocked catheter

‘eyes’▫ Blocked terminal eye -> higher incidence of

unsatisfactory blocks (32%) compared to lateral eyes blocked

▫ Loss of resistance to air method -> higher incidence of inadequate analgesia compared to saline method

▫ Optimal length catheter left in space 2-6cm


4. Patient-related & other risk factors▫ Morbidly obese; BMI >30 higher risk failed

block & inadequate analgesia

▫ Presence of radicular pain during needle/catheter insertion

▫ Occipital posterior presentation of fetal head

▫ Inadequate analgesia from initial dose

▫ Labour duration >6 hours

Management of failed/inadequate epidural catheter in labour


• Reassure patient

• block inadequate, unilateral or if some dermatomes are spared?

1. Withdraw catheter until 2-3cm left in space then give another dose of analgesic

2. Change patient position when administrating the epidural. eg:

Supine position for unilateral block Sitting up position for sacral block*results of effectiveness mixed


3. Changing loading dose Bigger volume of bolus dose of dilute

epidural analgesic (eg 0.125% ropi/less) shown to be >effective than smaller volume but >concentrated dose (eg 0.2% ropi)

4. Add opiates & other adjuvants Boluses epidural fentanyl 25-50mcg Others, boluses clonidine 150mcg


•If failed to get sensory block after 30 minutes, consider:

1. Resite epidural catheter


2. Perform CSE▫ Risk high block if spinal dose is too large &

extend of block may be unpredictable

▫ If desired dermatome level not reached after spinal, upper sensory level may be increased by injecting 5mls saline epidurally ( epidural volume extension (EVE))

▫ Upper sensory block tends to be several dermatomes higher after CSE than in plain epidural top-ups, especially if done after induction of analgesia.


3. Perform single shot spinal• May be considered if delivery is imminent &

risk for c-sec is minimal

• Use of hyperbaric LA solution given in sitting position very effective

• Progression of block should be monitored closely

• Epidural top-ups should not be administered during the last 30 minutes(if time permits)

• May need to reduce dose by 20-30% than usual


4. Supplemental caudal anaesthesia

• Performed when the unblocked segments are sacral

• Should be done by experienced practitioner with carefully calibrated doses

• Generally not recommended due to high risk of local toxicity & accidental injected to foetus


5. If insufficient time to resite epidural, • supplementary systemic analgesic e.g. • small doses fentanyl/remifentanil every

1-2 mins;• entonox,• local (perineal anaesthesia)

Extending epidural analgesia for caesarean

section

Principles of management

•Patient should be transferred quickly to OT for top ups where monitoring & resuscitation equipment available▫Potential adverse effect -> excessive high

block requiring intubation & accidental intravascular injection may result in seizures & cardiac event

•Performing test dose before epidural top ups may avoid potential complications, but may cause delay


•Regular follow up patient receiving epidural anaesthesia in labour

▫Identify patients with suboptimal block -> may have inadequate intraoperative anaesthesia after top-up lead to intraoperative convertion to GA


▫If c-sec is required, consider removing epidural catheter & convert to spinal/CSE

Reduce risk of inadequate anaesthesia & ad hoc conversion to GA.

*Risk of excessively high block, may considered lower dose of intrathecal drugs

Agents used to extend epidural blockade for caesarean section

•Usually 15-20mls of local anaesthesia needed to produce adequate block for c-sec

•Using combination of drugs & adjuvants produces faster onset anaesthesia

Local anaesthesia

I. Lidocaine 2%▫ Recent study showed that alkalanized 2%

lidocaine mixed with epinephrine 1:200,000 reduced onset time of anaesthesia & produced better quality anaesthesia

II. Ropivacaine 0.75%-1%, levobupivacaine 0.5%

▫ Less likely produce cardiac complications compared to bupivacaine

Adjuvants I. Epinephrine

▫ Reduces toxicity risk by decreasing systemic absorption of local anaesthetics from extradural space

▫ Confer some additional analgesic property

▫ Cause tachycardia if injected intravascular, hence warn the intravascular migration of epidural catheter

Adjuvants II. Sodium bicarbonate

▫ May increases speed of onset of surgical anaesthesia by increasing pH -> increase proportion of non-ionized lipid soluble LA that can diffuse into the axon

III.Opioids ▫ Improve quality of anaesthesia

Inadequate regional anaesthesia for caesarean section

•Regional anaesthesia recommended for caesarean section

▫Provide effective postoperative analgesia via intrathecal/epidural opioids

▫Avoiding GA hazards eg difficult/failed airway, aspiration of gastric contents

Prevention

a. Preexisting epidural analgesia

b. Choice of regional anaesthesia technique

c. Use of opioids

d. Testing of block

e. Time consideration

f. Miscellaneous consideration

Pre-existing epidural analgesia

•Functioning epidural allows sufficient time to top up for pain free emergency c-sec

•Epidural catheter should be checked to ensure that its functioning well.

Pre-existing epidural analgesia•If amount of LA to maintain analgesia

during labour significantly higher than usual

▫may due to non functioning epidural catheter & may need to be replaced

•Regular review & identifying high risk parturient early can help reduce incidence of emergency surgery that needed GA

Choice of regional anaesthesia technique

•Single shot spinal anaesthesia ▫ not extendible in event of inadequate

anaesthesia

•If surgery expected to be longer & difficult than usual -> CSE may be a better option

Use of opioids

•Fentanyl + intrathecal bupivacaine faster onset improve perioperative anaesthesia without increase in side effects if moderate doses are used

•Intrathecal morphine/diamorphine prolonged postoperative analgesia

Testing of block•Usual ways

▫Loss sensation to touch/pressure,▫Cold temperature &▫Pin prick

•Light touch > reliable predictor for adequate SA

•Loss of pinprick sensation to T4 acceptable in epidural anaesthesia▫Bilateral LL weakness -> indicator top ups

in epidural taking effect

Time consideration

•Time should be given for surgical anaesthesia to develop, particularly for epidural block▫May not be feasible in extremely emergent

situation eg cord prolapse/severe foetal distress

•Patients with epidural catheter in situ for labour analgesia, additional bolus doses may be administered once the decision for caesarean delivery made.

Miscellaneous consideration•Presence of patient’s partner in OT may be reassuring & have calming effect on patient

•Sympathetic approach by anaesthesiologist + gentle approach at surgical dissection & manipulation by surgeon can help ensure patient comfort

Management of inadequate regional anaesthesia for caesarean section

•Management option depends on▫The indication & urgency of caesarean

section

▫The time of diagnosis of inadequate regional block

▫Pre-existing regional blockade (if any)

▫The nature & severity of the pain experienced

•Risk of GA & regional anaesthesia must be considered for patients▫morbidly obese

▫exhibit features of potential difficult airway

▫have active respiratory tract infection

*in such situation, GA must be undertaken with extreme caution

Before surgery•Problems with epidural anaesthesia

▫A failed block

▫A unilateral or patchy block

▫A block height remains persistently below required T4 level

Before surgery•Measures that can be done to improve block▫Provide additional doses of LA

with/without opioids

▫Adjusting epidural catheter

▫Positioning the patient on unblocked side before top-ups

Before surgery

•Its crucial to identify non-functional epidural block perioperatively before administering maximum volume of local anaesthetic

•If there’s no time constraint & no technical difficulty in administering the first epidural block -> possible to replace epidural catheter. ▫Risk of excessive local anaesthetic

Before surgery

•Use of spinal anaesthesia following failed epidural block -> highly controversial.

*may cause high block requiring tracheal intubation, ventilation & cardiovascular resuscitation.

•However, it still can be an option if appropriate precautions & technique modifications are taken such as▫Avoiding epidural boluses immediately

before spinal injection

▫Using a lower spinal dose

▫Intentionally delaying the placement of patient in a supine position following spinal injection of hyperbaric of LA in sitting position

Before surgery

Before surgery •Failed spinal block can occur despite

presence of CSF backflow due to anatomical anomalies or drug failure

•Management include ▫CSE placement at different lumbar

interspaces▫If needed, proceed to GA

During surgery before delivery of foetus

•Some patients may be anxious about being fully awake during procedure -> often requiring reassurance

•If an epidural catheter is present▫Additional top ups 3-5 mls of LA (eg 2%

lidocaine with 1:200,000 adrenaline & NaHCO3) may be given together with 50mcg fentanyl

During surgery before delivery of foetus

•Other options include ▫Entonox▫small iv doses of ketamine or▫ short acting opioids (eg alfentanil)

•Conversion to GA should be strongly considered in patients whose pain persist despite of the above interventions

During surgery after delivery of foetus

•Management option include ▫the previous measures▫use of iv longer acting opioids (eg meperidine,

morphine)

•Patient must not be over sedated to maintain airway & protect against gastric aspiration

*explain to patient post delivery to explain regarding failed blocks & management option available if she presents again in future.

Conclusions •Using combination of drugs & adjuvants

produce faster onset but may delay time•Mixing several drugs together may lead to

drug errors•Epidural has multiple benefit but has up to

14-20% failure rate•In situation where epidural anaesthesia not

functioning in patient posted for EMLSCS, decisions regarding other modalities need to be discussed with specialist

•Documentation

Reference

morbidity review by noorfarahnaduwah nurdin supervisor dr tuan norizan

Documents

epidural anaesthesia

epidural catheter

failed epidural block

mlshr slide

icu slide

mshr slide

phenylephrine slide

ot epidural