Upload
others
View
4
Download
1
Embed Size (px)
Citation preview
Obstetric Anaesthesia UpdateInfomed Update for the General Anaesthetist 20th June 2019
James EldridgePortsmouth Hospitals NHS Trust
Plan
• Labour Analgesia
➢ Opiate analgesia
➢ Epidural analgesia
➢ NRFit
➢ Enhanced recovery
• Managing complications and emergencies
➢ Airways
➢ Hypotension and spinal anaesthesia
➢ Post dural Puncture headache
➢ Haemorrhage: fibrinogen and tranexamic acid
Opiate analgesia
Diamorphine vs Pethidine
• 7.5mg IM diamorphine vs 150mg IM pethidine
• 484 women
Wee IJOA May 2012
Better pain relief: Diamorphine p
Remifentanil2014 - available in 50% of UK delivery suites
OAA survey 154 Clark
Remifentanil
Pharmaco-kinectics:
• Rapid onset & short duration
o Non-pregnant context-sensitive half-time 3 mins
o Effect site peak conc at 1-2 mins
o Large variations in pharmacokinetics in pregnant women (generally lower plasma concentrations)
• Rapid and extensive transfer across the placenta
o UV to MA ratio of 0.88
• Rapid fetal metabolism
o UA/UV 0.29
Remifentanil
Used across Europe and North America
Side effects– Sedation
– Nausea
– Reduced FHR variability
–Maternal hypoxia (30%)– 5% of labour with Sats < 90%
Technique• 1-to-1 care
• No opioid within 4 hours
• Dedicated iv (care with BP cuff)
• PCA with bolus dose of 40mcg and lockout of 3 min
• Continuous pulse-oximetry.
• Give O2 if SpO2 < 94% on air.
• 30 minutely observations of respiratory rate, sedation score and pain scores.
• Flush the cannula
Editorial Machatuta Anaesthesia 2013
Remifentanil
Efficacy:
• Modest pain relief (37 studies but mostly poor quality)
o Slightly better analgesia than nitrous oxide
o Better than pethidine
o Inconclusive compared to other opiates
o Not as effective as neuraxial analgesia (nb difference between pain and satisfaction scores)
o Reduced efficacy in late labour
• Most likely to be effective in early 1st stage of labour.
PCA Remifentanil vs epidural analgesia (RCT)Freeman BMJ 2015
1414 women recruitedo705 Epidural (various low dose
regimens)
o709 Remifentanil PCA
In the remifentanil group:o In women who received pain relief,
satisfaction poorer than with epidural
o Higher pain scores
o Lower peak analgesia
o Higher worst pain score
o More frequent Sat
o Four reported Resp depressions (Resp rate < 8bpm)
Freeman BMJ 2015
“Caregivers should be aware that serious respiratory complications
can occur during administration of remifentanil”
RESPITE Trial: Remifentanil PCA vs IM PethidineWilson 2018 Lancet
• Open-label, multicentre (14 units), RCT
• 400 women
• Pethidine (100mg/4 hours, max 400mg)
• Remifentanil (40mcg, 2 min lockout)
• Outcome – epidural conversion
Remifentanil PCA
PethidineIM
Number of women 201 199
Epidural conversion 39 (19%) 81 (41%)
Significant reduction in epidural conversion (RR 0.48, CI 0.34-0.66, P< 0.0001)
RESPITE Trial: Remifentanil PCA vs IM PethidineWilson 2018 Lancet
• Open-label, multicentre (14 units), RCT
• 400 women
• Pethidine (100mg/4 hours, max 400mg)
• Remifentanil (40mcg, 2 min lockout)
• Outcome – epidural conversion
Remifentanil PCA
PethidineIM
p-value
Number of women 201 199
Epidural conversion 39 (19%) 81 (41%)
RESPITE Trial: Remifentanil PCA vs IM PethidineWilson 2018 Lancet
• Open-label, multicentre (14 units), RCT
• 400 women
• Pethidine (100mg/4 hours, max 400mg)
• Remifentanil (40mcg, 2 min lockout)
• Outcome – epidural conversion
Remifentanil PCA
PethidineIM
p-value
Number of women 201 199
Epidural conversion 39 (19%) 81 (41%)
Muchatuta NA, Kinsella SM
BEWARE OCCASIONAL USERS / NEW STARTERSBEWARE COMPLACENCY
Epidural Analgesia
Randomised studies of epidural analgesia in labour40 RCT
• >11,000 women
• 34 epidural vs opiate
•7 epidural vs no pain relief
• (4 trials had more than 2 arms)
Anim-Somuah Cochrane DB 2018
RCTs of Epidural vs OpiateNo of trials No of
WomenEffect of epidural analgesia
Pain Scores 5 1133 Better pain reliefSMD* -2.64
CI -4.56-0.73
Satisfaction with pain relief
7 1911 Better satisfactionRR 1.44
CI 1.03-2.08
Caesarean section 33 10350 No differenceRR 1.07
CI 0.96 – 1.18
Assisted vaginal delivery
30 9948 Increased(only if pre2005 trials included)
RR 1.44CI 1.29 -60
Fever 9 4276 IncreasedRR 2.51
CI 1.67-3.77
Neonatal Admission to NICU
8 4488 No differenceRR 1.03
CI 0.95-1.12
Apgar score
Neuraxial analgesia and instrumental delivery
Low dose (≤ 0.1% bupivacaine)
• 18 RCT studies
• 2284 women
• Reduces instrumental deliveryOR 0.77 (CI 0.64-0.93)
Sultan IJOA May 2012
Neuraxial bolus or infusion and instrumental delivery
• Midwifery top-ups
• Epidural infusions
• PCEA +/- epidural infusion
• Programmed intermittent epidural bolus +/- PCEA
Kaynar Anesth Anal 1999
Neuraxial bolus or infusion and instrumental delivery
• Bolus techniques reduce total amount of local anaesthetic used
• Bolus techniques may reduce motor block and instrumental delivery rate
Capogna G, Anesth Analg. 2011George R, Anaesth Analg. 2013 (Meta-analysis)Bullingham A, Br J Anaesth. 2018Sng B, Cochrane Database Syst Rev. 2018 (Meta-analysis)
Optimal bolus volume
Individual responses of women to different programmed
intermittent epidural bolus (PIEB) volumes. Filled circle –ineffective PIEB volume; open circle –effective PIEB volume.
The estimated Effective Vol90 was 11.0 ml (95%CI 10.0–11.7)
Neuraxial analgesia to minimise instrumental delivery
• Low concentration solutions
• No background infusion
• Large volume epidural boluses (10 -11ml) • PIEB (Programmed Intermittent Epidural
Bolus)
• PCEA
Dural puncture in labour neuraxial analgesia
• Dural puncture improves analgesia• 25G PP needle – reduced unilateral block, improved
pain score
• CSE may reduce duration of 1st stage of labour• Controversial
• Not enough evidence to routinely recommend CSE labour analgesia
May have benefit for
• Women out of control (rapid onset)
• When re-siting epidurals (re-establish confidence)
Cappiello Anesth Analg. 2008; Simmons Cochrane Database Syst Rev. 2012
Dural Puncture Epidural vs epidural vs CSE
• DPE quicker than epidural
• DPE and CSE better sacral block
• DPE less fetal bradycardia than CSE
Chau Anesth Analg 2017
Epidural Space and BMI
Clinkscales IJOA 2007
Effect of epidural adipocytes on neuraxial anaesthesia and analgesia• Increased spread of block with
epidural anaesthesia
• Some increased spread of block with spinal anaesthesia
• Reduced chance of PDPH with spinal needle
• ? Reduced chance of PDPH with ADP with Tuohy needle
Kuntz Neurolgy 1992Lavi Neurolgy 2006Besov Headache 2010Jabbari Caspian J Intern Medicine 2013
Miu IJOA 2014Peralta Anesth Anal 2015Franz J Clin Anaesth 2017Song IJOA 2017
D’Angelo Anesthesiology 2014
Lumbar neuraxial ultrasound for spinal and epidural anesthesia: A systematic review and meta-analysis
• Identifies interspace more accurately
• Estimates depth of space accurately (+/- 3 mm)
• Improves efficacy of epidural
• Insufficient evidence to demostrate improvement in safety
Perlas 2016 Regional Anaes & Pain Med
NRFit ISO 80369 Series 6
80369-6 applications involve the use of medical devices to administer medications to and take samples from neuraxialsites (central nervous system including intracranial and spinal canal such as epidural and intrathecal), major peripheral nerve local anaesthetic blockade and continuous wound infiltration. This includes anaesthetic delivery, monitoring cerebro-spinal fluid (CSF) pressure, and removing CSF for therapeutic or diagnostic purposes.
ISO 80369 Standards
ISO Standard Use/Application Common Name
80369 – 2 Breathing systems and driving gases
80369 – 3 Enteral applications ENFit
80369 – 4 Urethral and urinary applications
80369 – 5 Limb cuff inflation
80369 – 6Neuraxial applications and major
regional anaesthesiaNRFit
80369 – 7Intravascular or hypodermic
applicationsLuer
International Organization for Standardization
Longer than Luer 20% smaller diameter Collared slip syringes
Luer
NRFit
(Yellow Colour)
NRFit ISO 80369 series: HOWTO Guide to the transition processISO 80369-6 Implementation of Neuraxial devices in the UK
01/06/2016
This paper is a case study of local practice and was reviewed by the NHS Small Bore Connector Clinical Advisory Group, who agreed that the information would be useful for other Trust when implementing new neuraxial connectors.
Dr Paul Sharpe, Chairman of NHS England Small Bore Connector Advisory Group. Consultant Anaesthetist University Hospitals of Leicester NHS Trust.
Dr Ian Shaw, Consultant Anaesthetist, Sheffield Teaching Hospitals NHS Trust.
Mr Pete Phillips, Director, Surgical Materials Testing Lab, Princess of Wales Hospital, Bridgend, South Wales
https://goo.gl/mERxFo
Step 1: Identify the disciplines affected by the conversion.
Step 2: Recruit staff to be involved in the changeover.
Step 3: Identify what kit you currently use.
Step 4: Check with your supplier that they will provide ISO 80369-6 versions of these devices.
Step 5: Ensure that your expert advisors have early sight of the new devices.
Step 6: Understand your off-label usage and ensure continued supply.
Step 7: Ensure that the pharmacy aseptic service has appropriate device options.
Step 8: Obtain senior management approval.
Step 9: Plan the timetable.
Step 10: Educate your staff.
Step 11: Provide demonstration sets
Step 12: Co-ordinate with suppliers
Step 13: Produce an exchange box for each clinical area
Step 14: Conversion Day
Step 15: Continue to provide support
Plan
• Labour Analgesia
➢ Opiate analgesia
➢ Epidural analgesia
➢ NRFit
➢ Enhanced recovery
• Managing complications and emergencies
➢ Airways
➢ Hypotension and spinal anaesthesia
➢ Haemorrhage: Fibrinogen and tranexamic acid
Enhanced Recovery
Portsmouth >50% elective and emergency CS discharged Day 1 since 2012
Early discharge after CS• Organisation
• Catheter removal, neonatal review, TTOs
• Expectation
• Mother
• Staff
• Community support
• Enhanced Recovery Techniques• Patient selection• Patient information• CHO loading• Neuraxial techniques• Delayed cord clamping• In theatre skin-to-skin contact• Analgesia paracetamol, NSAIDS, oral
opiates• Early oral intake• Early mobilisation• Early catheter removal
Post Dural Puncture
Headaches
MBRRACE 2014
Lessons
• Importance of thromboprophylaxis
• Importance of recognising PDPH
• Communication with GP
• Arranging follow-up until resolution
• Serious neurological symptoms require urgent referral and/or imaging
• If reduced LOC, transfer must be with appropriate medical (anaesthetic) involvement
MBRRACE 2014
Key points
• 5% PDPH are not postural• Incidence of PDPH
• >50% after 16/18G Tuohy• 1/3 dural puncture was not
recognised
• 1.5-11.2% after spinal anaesthesia
• Rare but serious complications include cerebral vein thrombosis and intracranial haemorrhage, cranial nerve palsies (VI & VII), seizures
• Bed rest may provide temporary relief (DVT prophylaxis)
• Simple analgesics should be used• Caffeine may be tried, but
treatment limited to 24 hours. Benefit limited to 4 hours. Possible ↑ risk of seizures.
• No or insufficient evidence for all other treatments apart from blood patch.
• This includes: other theophyllines, ACTH and analogues, steroids, triptans, gabapentinoids, DDAVP, methylergonovine, ondansetron, acupuncture, greater occipital nerve block, spenopalatine ganglion block, epidural morpine, epidural crystalloids, dextrans, HES, gelatin, or fibrin glue.
Key points
• Blood patch success rates• Early studies suggested >90%• Recent studies suggest
• complete success 30%• Complete or partial success 50-80%
• Timing• EBP
Airways
• OAA DAS guideline
Cause of Anaesthetic Deaths:Failed Airway Management
Total
Deaths associated with
failed airway
Confidential Enquiries into Maternal Deaths
OAA DAS obstetric airway guidelines 2015
Obstetric Anaesthetist Association
Criteria on whether to wake or proceed following failed intubation at caesarean section.From OAA DAS guideline
Proceed with surgery
• Spontaneous or controlled ventilation
• Consider muscle relaxation • Reduces laryngospasm, gastric insufflation, peak airway pressure and facilitates surgery.
• Most experienced surgeon
• Minimal fundal pressure
• Neonatal team informed
• Cricoid pressure until delivery
• 2nd generation SAD + gastric drain tube.
• Try to avoid further instrumentation of airway but:• Be prepared for front of neck
• If familiar consider fibreoptic scope
Hypotension and spinal anaesthesia
International Consensus on the management of hypotension with vasopressors during caesarean section under spinal anaesthesia.Kinsella SM, Carvalho B, Dyer RA, Fernando R, McDonnell N, Mercier FJ, Palanisamy A, Sia ATH, Van de Velde M, Vercueil A; Consensus Statement Collaborators.
10 Recommendations …
1. ↓BP is common after spinals and is bad for mother and baby
2. Vasopressors should be used routinely and preferably prophylactically
3. α-agonists are most appropriate, although agents with a small amount of βactivity may have advantage.
4. Left lateral and fluid co-load should be used.
5. Aim to maintain sBP > 90% of baseline (with variable rate infusion of phenylephrine, starting at 25-50 mcg/min)
Anaesthesia 2018, 73,71-92
International Consensus on the management of hypotension with vasopressors during caesarean section under spinal anaesthesia.Kinsella SM, Carvalho B, Dyer RA, Fernando R, McDonnell N, Mercier FJ, Palanisamy A, Sia ATH, Van de Velde M, Vercueil A; Consensus Statement Collaborators.
10 Recommendations …
6. Maternal heart rate is a surrogate for cardiac output - ↑HR &↓HR should be avoided
7. If ↓HR consider ephedrine. If ↑BP consider anticholinergic.
8. Smart pumps or two vasopressors may have advantage
9. Women with PET require less – start cautiously
10. Women with cardiac disease should be assessed individually
Anaesthesia 2018, 73,71-92
Norepinephrine Advantages
• ↓maternal bradycardia with ↑cardiac output compared to phenylephrine
• Diluted concentration can be used peripherally as an infusion or IV bolus (5mcg/ml)
• Equipotency to phenylephrine (Ngan Kee study)• Random allocation, graded dose response study
• 180 healthy patients
• Spinal anaesthesia for elective CS
• Estimated equipotency: 100mcg phenylephrine = 8mcg norepinephrine (95% CI, 6 to 10mcg)
Ngan Kee Anaesth Analg 2018; Ngan Kee Anesthesiology 2017
Norepinephrine safety concerns
Potential subcutaneous tissue ischemia with inadvertent extravasation
• High concentration epinephrine in recipient vein and adjacent blood vessels
• Marked vasoconstriction and increased vascular permeability
Significant decrease in peripheral tissue oxygenation
SOAP 2018Fred Hehre Lecture
12 May 2018
“Like sending a man to do a boys work”
Professor Robert Dyer
Plan
• Labour Analgesia
➢ Opiate analgesia
➢ Epidural analgesia
➢ NRFit
➢ Enhanced recovery
• Managing complications and emergencies
➢ Airways
➢ Hypotension and spinal anaesthesia
➢ Haemorrhage: fibrinogen and tranexamic acid
Haemorrhage: Fibrinogen in Pregnancy
Non-pregnant
First trimester
Second trimester
Third trimester
Fibrinogen (plasma)
g/L
2.3-5 2.4-5.1 2.9-5.4 3.7-6.2
Fibrinogen < 2 g/l is an early predictor for severe
PPH
Abbassi-Ghanavati Obstet Gynecol. 2009 Charbit B J Thromb Haemost 2007, de Lloyd IJOA 2011,
Lilley OAA Abst. 2013
Bedside testing: Coagulation
• Thromboelastography• TEG
• Thromboelastometry• ROTEM
• Fibtem
Fibrinogen as treatment
Aim to keep Fibrinogen > 2.0 g/L
Fibrinogen content(g/L)
FFP 1.6-3.6
Cryoprecipitate 3.5-30.0
Fibrinogen concentrate
• 20,060 women• Recruitment 2010-2016• 193 hospitals• 23 countries
• Age ≥ 16 • Clinical diagnosis of postpartum haemorrhage
• Blood loss > 500 ml vaginal delivery or > 1000ml after CS
• Allocated to 1g tranexamic acid or placebo• A second dose could be given if bleeding continued for 30
minutes or restarted within 24 hours
Lancet 2017 389
Effect of tranexamic acid on maternal death
Tranexamic acid group(n=10036)
Placebo group(N = is 9985)
RR (95% CI) p value(two-sided)
Bleeding 155 (1.5%) 191 (1.9%) 0.81 (0.65-1.00) 0.045
Pulmonary embolism 10 (0.1%) 11 (0.1%) 0.90 (0.38-2.13) 0.82
Organ failure 25 (0.3%) 18 (0.2%) 1.38 (0.75-2.53) 0.29
Sepsis 15 (0.2%) 8 (0.1%) 1.87 (0.79-4.40) 0.15
Eclampsia 2 (0.02%) 8 (0.1%) 0.25 (0.05-1.17) 0.057
Other 20 (0.2%) 20 (0.2%) 0.99 (0.54-1.85) 0.99
Any cause of death 227 (2.3%) 256 (2.6%) 0.88 (0.74-1.05) 0.16
Timing of tranexamic acid
Have readily available checklists
Plan
• Labour Analgesia
➢ Opiate analgesia
➢ Epidural analgesia
➢ NRFit
➢ Enhanced recovery
• Managing complications and emergencies
➢ Airways
➢ Hypotension and spinal anaesthesia
➢ Haemorrhage: fibrinogen and tranexamic acid