The Obese Parturient
Prof A. Shennan
Dr G O’Sullivan
Geraldine O’Sullivan
St Thomas’ Hospital, London
Confidential Enquiries into
Maternal and Child Health
London Maternal Death Review
Centre for Maternal and Child Enquiries. A Review of Maternal Deaths in London January 2009 – June
2010 http://www.london.nhs.uk/publications/independent-publications/independent-reports/a-
review-of-maternal-deaths-in-london-january-2009-june-2010
NHS London concern ↑ maternal deaths (2010)
London Midwifery Supervising Authority asked
CMACE to review 18/12 of deaths 2009-10
London’s MMR significantly higher than rest of UK
19.3 [95%CI 14.0,26.6] vs 8.6 [95%CI 7.1,10.5]
http://www.london.nhs.uk/publications/independent-publications/independent-reports/a-review-of-maternal-deaths-in-london-january-2009-june-2010
Bewley S, Helleur A. Rising maternal deaths in London, UK. Lancet 2012;379:1198
8.6 UK
19.3 London
CMACE
2009-10
London’s Demographics
Age: High % at extremes of young and old
Deprivation: Wide variation
Ethnicity: Non-white ranges 32-79% (Kingston vs Barts)
53% of births to mothers born outside Britain
300 languages
Births: 20% of all UK births occur in London
Multiples: Twins 3.5% (IVF & spontaneous)
Widening ethnic, multi-cultural society, & families >2.5
Higher profile of complex medical & social needs
Which women died in London?
Older - 33% >35
Black & minority ethnic – 66%
Non-UK origin - 68%
Deprived - 52% in quintiles 4 & 5
Obese - only 50% normal BMI 18.5-24.9
Booked late or not at all - 45%
High social, psych, medical co-morbidities
72% had a caesarean (16% perimortem)
37% did not have a live birth
75% had avoidable factors (professionals, services, woman & family)
Recommendations made, reports sent to local units
Prevalance of obesity
OECD Data
2005
NEJM
Failure of Public Health Medicine
WHO; Clinical classification
BMI
• < 18.5kg/m2 Underweight
• 18.5 - 24.9kg/m2 Healthy
• 25.0 – 29.9kg/m2 Overweight
• 30.0 - 39.9kg/m2 Obese
• > 40kg/m2 Morbidly Obese
• > 50kg/m2 Super Obese
Limitations of BMI ?
Monitor weight gain
Hippocrates
‘Corpulence is not
only a disease itself,
but the harbinger of
others’.
Maternal Obesity in the UK
• UK and US
– 20-40% gain more
than recommended
wt
Weight Gain in Pregnancy
BMI (kg/m2) Weight gain (kg)
< 18.5 12.7 – 18.0
18.5 - 24.9 11.4 – 16.0
25 - 29.9 6.8 – 11.0
30.0 or more 5.0 – 9.0
Institute of Medicine 2009
Weight gain in Pregnancy
BMI (kg/m2) Weight gain (kg)
30.0 - 34.9 4.5 - 11
35.0 – 39.9 0 - 4
40.0 or greater Weight loss of 0 to
more than 4.5
Calculated optimal weight gain with lowest risk of
adverse perinatal outcome.
120,000 women in Missouri. 2007
Obesity
• A simple metabolic equation
Calories absorbed Weight
Calories expended
With a difficult behavioural solution
• Obstetrics/Obstetric Anaesthesia
Provide safe and effective clinical care
Obstetrics and Obesity
• Infertility –
– anovulation x 3 if BMI > 27 kg/m2
• First trimester loss
• Late pregnancy loss
• Prioritising for fertility treatments ???
• New Zealand. BMI - 18-32 kg/m2
• Fertility rates
– > 32 kg/m2 = 38%
– < 32 kg/m2 = 52%
Obstetrics and Obesity
• Multicentre study 16,102 women• 85% BMI < 30. 9% Obese. 6% Morbid Obese
• Pregnancy Induced Hypertension
– > 2.5 in obese. > 3.2 morbid obesity
• Gestational diabetes mellitus
– > 2.6 in obese. > 4.0 morbid obese
• Pre-term delivery. (OR 1.5, 95% CI 1.1-1.2)
Am J O&G 2004;190:1091
Maternal BMI and risk of Pre-eclampsia
Maternal BMI and risk of Pre-eclampsia
• With each 5 – 7kg/m2 increase in pre-
pregnancy BMI
• Risk of PET doubles
– Epidemiology 2003;14:368
Obesity and Diabetes
• Danish study of 8092 women
BMI OR developing GDM
< 25kg/m2 1
25 - 29kg/m2 3.4
> 30kg/m2 15.3
Obstet Gynecol 2005;105;537
Obesity and Caesarean Section
BJOG 2006:113:1173
Obesity and VBAC
• Vaginal Birth after Caesarean section
– 50% less likely to be successful
– Compared to women with normal BMI
– Obstet Gynec 2005;106:741
Obesity and Thrombo-embolism
• North West Thames, London database
– 287,213 pregnancies
– 27.5% overweight
– 11% obese
• Thromboembolism
– 0.04% normal weight
– 0.07% overweight
– 0.08% obese
Obesity and Thrombo-embolism
• Thromboprophylaxis
– (RCOG and CMACE)
Enoxaparin
– 40mg - up to 89kg
– 60mg – 90 -130kg
– 80mg – 131-170kg
– > 170kg – 0.6mg/kg/day
Obesity and Complications
• North West Thames, London database
– 287,213 pregnancies• 27.5% overweight
• 11% obese
• Wound infection
• PPH
• Reduced incidence of breast feeding
• Increased hospital stay
Obesity in Pregnancy
• Major predictor of…………..
• Obesity in later life
– Chronic hypertension
– Type 2 DM (40%)
– Dyslipidaemia
– Gall stones
– Endometrial cancer
Don’t forget me!
Obesity and the fetus
• Congenital anomalies– Neural tube
– Cardiac
• Diagnostic and monitoring difficulties
• Still birth and neonatal death
• Macrosomia– Shoulder dystocia (fire drills)
– McRobert’s Manoeuvre
Obesity and the fetus
• Congenital anomalies– Neural tube
– Cardiac
• Diagnostic and monitoring difficulties
• Still birth and neonatal death
• Macrosomia– Shoulder dystocia (fire drills)
• Admission to neonatal ICU
• More likely to be obese adults X 9
Obesity and Obstetrics
• Be prepared
• Be on holiday !
Confidential Enquiries into
Maternal and Child Health
Obesity; Antenatal assessment
• Antenatal anaesthetic clinic
• BMI > 40kg/m2 (??? 50)
• History and clinical examination
–Airway assessment
–Obstructive sleep apnoea (OSA)
• CPAP
–Assessment for regional anaes/analg
–Weight (loss/gain)
Fig 6 Relative risk of effects of weight management interventions in pregnancy on maternal outcomes.
Thangaratinam S et al. BMJ 2012;344:bmj.e2088
©2012 by British Medical Journal Publishing Group
Obesity; Antenatal Anaesthetic
Assessment
• Mode of delivery – obstetric decision
• CMACE
– Anaesthetist to be informed when woman
BMI > 40kg/m2 is admitted
– IV cannula
• If vaginal delivery planned
– Consider early epidural
– ‘Must be effective and secure’
– Assess for potential ‘crash section’
‘Crash’
Caesarean section
‘Delivery < 30 min
Is it possible?
CMACE
ST 6 or senior
Obesity and Obstetric Anaesthesia
Practicalities
• Blood pressure cuffs vs arterial line
• Venous access
– Peripheral vs central
– Ultrasound ??
Arterial line under LA prior to
induction
OR – BP cuff on forearm?
Obesity and Surgery/Anaesthesia
Practicalities
• Op table
• Surgical equipment
• RA needles
• Equipment for GA
Obesity; Practical Points for
Anaesthesia
Padding everywhere
Positioning for regional analgesia
Lucien Freud
Ultrasound
Midline
Siting the epidural
• Ultrasound
– Helps identify
midline
– May help define level
of vertebra
– Measure depth of
space
– BUT---in the obese
Ultrasound
Ultrasound
Ultrasound
Ultrasound image in the paramedian sagittal oblique plane
Sahota J S et al. Anesth Analg 2013;116:829-8351
Ultrasound image in the transverse median plane
Sahota J S et al. Anesth Analg 2013;116:829-835
Which Interspace?
Higher is easier
Tilt the bed/table
Landmark location?
Line between gluteal cleft and cervical spines
Obesity and Epidural Anaesthesia
• Easier to perform ??
• Easier to titrate dose
• Reduced incidence of hypotension
• Facilitates prolonged surgery
• Post-op analgesia
• Fewer thrombo-embolic episodes ?
CSE
• Needle through needle ?
OR
• Separate spaces ?
Obesity and Regional Anaesthesia
Obesity and Block level (Spinal)
Surgery Agent & Dose N BMI Effect Ref
CS Bup 12mg 50 No A&A 1988
CS Bup 12mg 52 No Anes 1990
CS Bup -12.5mg 20 No IJOA 2004
PPTL Lig 75mg 44 No Reg An 1994
Hyperbaric LA
Assessment for Anaesthesia
• Regional anaesthesia preferred
• BUT –
– Must have a Plan B
Obesity and General Anaesthesia
Obesity and General Anaesthesia
• Careful airway assessment
– Breast size
– Airway oedema
– Chin to Chest distance
– Range of head and neck movement
• Two anaesthetists
• Awake fiberoptic intubation
Intubation Aids
Time to Hb desaturation.
SaO2 vs time of apnoea
Benumof. Anesthesiology 1997;87:979
Time to Hb desaturation.
SaO2 vs time of apnoea
Benumof. Anesthesiology 1997;87:979
Obesity and General Anaesthesia
Awake fibreoptic intubation ?
http://www.clinipol.co.uk/LMA2.gifhttp://www.clinipol.co.uk/LMA2.gif
Ventilation strategies in the obese
• Meta-analysis.– BJA 2012; 109:493
• No differences between
– pressure controlled vs volume controlled
ventilation
• Recruitment manoeuvres + PEEP
– superior to PEEP (5-10cm) alone
• RM = increase PEEP, increase insp pressure
or both for short periods of time
Obesity and General Anaesthesia
• Mother must not be endangered to
deliver a distressed fetus
Airway classification
1999; 93:648-52
Obesity. The Human Element
• Social and professional stigmatization
• Obese less likely to go to university
• Employment discrimination
• Lower socio-economic group
• Less likely to be married
• Society
– Model-like slimness
Obesity. The Human Element
• Embarrassed and anxious
• Respect and kindness
• Pregnancy
– Not the time for weight
loss ???
– OR gain
• Honest about risks (not
frightening).
• Post-partum
– Inform re ongoing risks
– Bariatric surgery
Obesity. Treatment
• Adjust food intake
– Until normal body wt is restored
• ‘Diets don’t work’
• Exercise
• Most effective therapy
– Bariatric surgery
Bariatric surgery
• Fertility may improve
• ?? delay conception for 18-24 months
• Gastric band– Surgical monitoring, might need adjusting
• Nutritional deficiencies not uncommon– Fe, Folic acid and Vit B12
– Vit D and calcium
• Not an indication for CS
Positive factors about Obesity
in OB anaesthesia ??• ? Reduced
incidence of PDPH
Management of Women with
Obesity in Pregnancy
OAA: Information for Mothers
Society for Obesity and
Bariatric Surgery
www.SOBAuk.com
See www.SOBAuk.com for references
THE SOCIETY FOR OBESITY AND BARIATRIC ANAESTHESIA GUIDELINES
ANAESTHESIA FOR THE OBESE PATIENT: BMI>35KG/M2
Preoperative Evaluation
Operative Management
Post Operative Management
Ramping Ear level with sternum. Reduces risk
of difficult laryngoscopy, improves
ventilation.
Drug dosing- what weight to use? Induction agents: titrate to cardiac output- this equates to lean
body weight in a fit patient. Competetive muscle relaxants: use ideal body weight.
Suxamethonium use total body weight to a maximum of 200mg Neostigmine: Increase dose
Opioids: Use Ideal body weight. Care with obstructive apnoea! TCI propofol: IBW plus 40% excess weight
If in doubt, titrate and monitor effect!
Lean Body Weight plateaus ≈90kg for a man, ≈70kg for a woman. Ideal Body Weight in Kg - Broca formula
Men: height in cm minus 100 Women: height in cm minus 105
Day Case Patients: Avoid long-acting opioids. Use multimodal analgesia including local anaesthetic. May discharge if
baseline SpO2 maintained on air without stimulation, no apnoea and routine discharge criteria attained. Consider LMWH for 10-14 days. Obstructive Sleep Apnoea or Obesity Hypoventilation Syndrome: Avoid sedatives and post-op opioids. Reinstate
CPAP if using it pre-op. Additional time in recovery recommended, only discharge to the ward if free of apnoeas
without stimulation. Patients intolerant of, or untreated with CPAP are at risk of hypoventilation and require continuous oxygen saturation monitoring. In-patients: Multimodal analgesia, caution with long-acting opioids and sedatives. Mobilise early. Ensure
thromboprophylaxis administered. Admit to HDU/ICU if significant co-morbidity or if major surgery undertaken.
Central Obesity (waist > half height)
Difficult airway /Ventilation problems more likely Greater risk of CVS disease
-Risk of Metabolic syndrome: Dyslipidaemia, Insulin resistance
Prothrombotic, Proinflammatory
Peripheral Obesity
(Fat outside body cavity)
Less co-morbidity
Anaesthetic Technique Anatacid premed, pre-op analgesia, careful
glucose control. DVT prophylaxis.
Self-position on operating table.
Preoxygenate & intubate in ramped position,
Minimize induction to ventilation interval to
avoid desaturation.
Avoid spontaneous ventilation.
Tracheal Intubation recommended.
Use short-acting agents e.g. desflurane or
propofol infusion. Short-acting opioids,
multimodal analgesia. PONV prophylaxis.
Ensure full NMB reversal.
Extubate and recover in head up position.
Suggested Equipment Suitable bed/trolley & operating table Gel padding, wide strapping, table
extensions/arm boards
Large BP cuff, or forearm cuff,
Ramping device, Step for anaesthetist
Difficult airway equipment, Ventilator
capable of PEEP and pressure modalities,
Hover mattress or equivalent.
Long needles and femoral cannulae
Ultrasound machine
Depth of anaesthesia and neuromuscular
monitoring.
Enough staff to move patient.
Any$of:$
Venus of Willendorf. 20,000BC
Venus de Cupertino
The Obese Parturient
Obesity and Obstetric Anaesthesia
Prof A. Shennan
Dr G O’Sullivan
Geraldine O’Sullivan
St Thomas’ Hospital, London