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