Jonathan Redman Consultant Anaesthetist, York Hospital The Preoperative Association Conference 7th November 2013

•! Risk assessment •! Assessment of comorbidity •! Preoptimisation •! Investigations •! Postoperative location •! Highlight any concerns"

Category" Obesity Class" BMI (kg/m2)"

Underweight" <18.5"

Normal" 18.5-24.9"

Overweight" 25.0-29.9"

Obesity" 1" 30.0-34.9"

Obesity" 2" 35.0-39.9"

Obesity" 3" 40.0-49.9"

Superobesity" 4" 50.0-59.9"

Super-superobesity" 5" 60.0- "

1980 1986 1992 1998 2004 2010 0

8

16

24

32

40

Males Females

1.!Health survey for England 2004"2. Forecasting obesity to 2010

Projected 2 %

Pop

ulat

ion

UK Ranked 3rd in world for obesity rates

2.1 million people in UK have BMI >40

•  Over 13,000 people with BMI > 40 living within catchment area of average DGH"

BMI>30 HR 1.5

BMI>35 HR 2.0

BMI>40 HR 2.5

•! Kuduvalli: BMI> 30 increased wound infection and AF (cardiac)

•! Zacharias: BMI>30 increased AF (cardiac)

•! Merkow : BMI> 30 increased PE, infection, renal failure (colorectal).

•! Myles : BMI> 30 increased pneumonia, UTI (obstetric)

•! The list goes on for urology, cardiac, general surgery"

RETROPSECTIVE

UNDERPOWERED

NO MENTION OF DEATH

Mullen. Annals of Surgery 2009;250:166+172

*

* *

* * *

*

•! Visceral fat metabolically active. •! Increased CRP, IL6, TNF (pro inflammatory) •! Decreased adiponectin (anti inflammatory) •! Increased macrophages in adipose tissue •! Chronic inflammatory state

Criteria" Essential" Central obesity"

Insulin resistance"

Lipid profile"

Hypertension"

Others"

WHO"

DM or insulin resistance and 2 others"

Waist to hip ratio:!M>0.9, F>0.85!

TAG!150 mg/dl and/or!HDL-C :!M<35 mg/dl!F<39 mg/dl"

!140/90"Urine albumin> 20 mcg/min"

NCEP"Any three of the following"

Waist circumference:!M>102 cm!F>88 cm!

Fasting glucose ! 110 mg/dl"

TAG!150 mg/dl !HDL-C :!M<40 mg/dl!F<50 mg/dl"

SAP>130!DAP> 85"

IDF"

Waist circumference and any 2 other risk factors"

Waist circumference:!M>94 cm!F>80 cm"

Fasting glucose ! 110 mg/dl or type II DM"

HDL-C :!M<40 mg/dl!F<50 mg/dl or treatment for HDL dyslipidaemia"

SAP>130!DAP> 85 pr previous HTN treatment"

Glance.Anesthesiology 2010; 113:859-72

•! 2-3 x cardiac complications •! 1.5-2.5 x pulmonary complications •! 2 x CNS complications •! 3-7 x acute kidney injury •! Increase in mortality if BMI>50"

•! Visceral fat •! Central obesity •! Metabolic syndrome •! Waist circ. > 102cm or 88cm •! Superior than BMI!"

•! Hyperlipidaemia •! Hypertension •! Arrhythmias •! Ischaemic heart disaese •! Pulmonary hypertension •! Obesity related cardiomyopathy

•! Difficulty in assessing functional capacity"

•! Bloods •! ABG •! ECG •! Spiometry •! CXR •! Echo •! PET"

•! 77 pts undergoing bariatric surgery •! BMI 43 •! Age 39 •! ECG •! Stress tests •! Echo "

ST abnormalities Negative LVH

Test" Abnormal"Change of management"

Outcome"

FBC" 0.7-4.8%" 0.2%" Emerging evidence"

Coagulation" 3.5-15%" <0.5%" No"

Biochemistry" 1.4-2.5%" 0-0.2%" No"

ECG" 4.6-31.7%" 0.6%"weak association in non cardiac surgery"

CXR" 2.5-37%" 0.5%" No"

Urinalysis" 1-34%" No"

•! Subjective ! History ! Questionnaire based ! Duke Activity Status Index"

•! Objective ! Measurements from a test ! Stair climbing ! Shuttle walk test ! Treadmill testing estimate of VO2

! VO2 peak (max) ! VO2 at Anaerobic Threshold from CPET

•! Major surgery causes physiological stress

•! Patients who do badly have indices of impaired tissue perfusion / oxygen delivery

•! Limitations of pre operative investigations.

•! Heart failure as risk factor"

McCullough et a. Chest 2006; 130;517-525"

•! 106 pts bariatric surgery

•! Length of stay 3 days ! AT 10.4 vs 11.3

•! Complication rates ! AT 9.9 vs 11.1

Hennis et al. BJA 2012; 109(4) 566-71

•!BMI>50 kg/m2

•!Hypertension •!Male •!Age>45 •!PE risk."

Study Incidence of mortality (%)

OS-MRS Class A

OS-MRS Class B

OS-MRS Class C

De Maria (2007) 0.31 1.9 7.56

De Maria (2007) 0.2 1.1 2.4

Efthimiou (2009) 0.3 1.5 3.0

Class A 0-1point

Class B 2-3 points

Class C 4-5 points

•! !O2 consumption !CO2 production •! Increased work of breathing •! Decreased FRC/ERV/TLC/VC •! Ventilation/perfusion abnormalities •! Restrictive lung disease •! OSA"

HYPOXIA QUICKLY!

PREDICTORS"

•! Neck circumference (NC) •! Thyromental Distance (TM) •! NC/TM ratio •! Mallampati •! History difficult intubation •! Cormack grade •! Wilson score

NON-PREDICTORS

•! Gender •! Age •! BMI •! Mouth opening

BJA 2011; 106: 743-8

•! Ramp the patient •! 45 degree head up •! Adequate pre oxygenation •! NO DIFFERENCE!"

Adequate pre oxygenation

Airway assessment •!Bag mask ventilation

•! No difference in intubation •! More difficulty with BMV •! Failed AFOI •! Inappropriate SAD •! Difficulties with emergence •! Less consultant presence"

•! Upto 10% adult population!

•! Upto 80% adults presenting for bariatric sx!

•! Undiagosed in 25% surgical pts!

•! Undiagnosed in 80% general population!

•! OSA is a killer!"

•! Repetitive airway occlusion during sleep!

•! Airway either obstructs or hypoventilation occurs!

•! Terminated when patient awakens or sleep lightens!

•! Many asymptomatic!

•! Common"

Av!Weight!in !lbs

What’s the problem?

1 hour

1st hr

8th hr

Start of drive End of drive

Tendency to wander OSA

Treated OSA

Sleep Apnoea as an independent Risk for All-cause mortality: The Bussleton Health study. Marshall et al!Sleep 2008. 31(8); 1079-85

Seet and Chung F Anesthesiology Clin. 2010:28:199-215

Cardiac

Hypertension 63-83% Heart failure!AF

76%!38%

AF 49% Dysrhythmia 58%

Respiratory Asthma 18% Pulm HT 77%

Metabolic T 2DM 36% Met Syndrome 50% Hypothyroid 45% Morbid obesity 50-90%

Surgery Bariatric 71% CNS 64%

Prevalence Condition

S"

Snoring- do you snore loudly (louder than talking or heard through a door?)" Y" N"

T" Tired-do you often feel tired or fatigued during the day?" Y" N"

O"

Observed- Has anyone observed you stop breathing during sleep ?" Y" N"

P"

Blood Pressure- Do you have or are you being treated for high blood pressure ?" Y" N"

B" BMI > 35Kg/m2" Y" N"

A" Age: > 50" Y" N"

N" Neck: > 16cm" Y" N"

G" Gender: male" Y" N"

If Answer Yes to 5 or more HIGH RISK

•! Highlight on preassessment chart •! Further investigation maybe required •! Increased risk of postop complications •! Follow OSA pathway"

•! Increased gastric Volume •! Decreased gastric pH •! Lower oesophageal dysfuntion •! Increased intra abdominal pressure •! Increased risk of hiatus hernia •! Hepatic fatty infiltration"

ASPIRATION RISK

ANTACID PREMED recommended

Increased gastric Volume Decreased gastric pH Lower oesophageal dysfuntion Decreased gastric pH

Obesity is a risk factor What is Ideal BM Periop consequences

Avoid hyperglycemia Perioperative management"

•! Prothrombotic •! Increased risk •! OCP •! What drugs? •! Dosing regimen?"

Prolonged immobilisation Total theatre time of >90 mins Age >60 BMI >30 Cancer Dehydration Positive family history of VTE.

•! 102 patients BMI > 37 for elective surgery •! Choice:

1/ Carry on 24 2/ Have a regional block 21 3/ Postpone op and try to lose weight 52 "

A.J.Coe et al. Anaesthesia , 2004, 59, 570-3

8 reduced BMI > 3 4 reduced BMI < 35

•! Risk assessment Obesity paradox,Metabolic syndrome

•! Look for evidence of cardiovascular disease Assess functional capacity, OSMRS

•! Look for evidence of pulmonary disease Airway, STOP-BANG >5 Plan the perioperative care

•! Forget Dieting "