obesity, osa and bariatric surgery

8/7/2019 Obesity, OSA and bariatric surgery

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Obesity, OSA and bariatric surgery

Teoh Sc



Case 1 of 20

` 31 year old cook

` Morbidly obes BMI 45

` Lap gastric banding

` HPT/DM/hyperlipidemia



Case 1 of 20

` Multidiscipline management

` Surgical, anaes, dietician, endocrinologist

` Premedication round ? OSA

` -snorring

` -HPT

` -?apnea

` -BMI

` -neck circumference 47cm` -male



Case 1 of 20

` ?delays surgery

` Benefit and risk



obesity



Obesity

` BMI=Weight(kg) / height2 (m)



Definition

WHO classification BMI cut off fordefinition

Asian BMI cut off for action

Underweight <18.5 <18.5

Normal 18.5-24.9 18.5-22.9

Overweight 25-29.9 23-27.4

Obese class I 30-34.9 27.5-32.4

Obese class II 35-39.9 32.5-37.4

Obese class III

(Morbid Obesity

40 37.5



Types

`

Primary or secondary` Central android

` waist/hip ratio > 0.9 in female & > 0.8 in male

`

Peripheral gynaecoid` Buttocks & thighs



Pharmacokinetics` Vd

` o blood volume

` o CO

` q lean body mass

` Protein binding normal` oVd for lipophilic drugs

` NormalVd for hydrophilic drugs

` oGFR & renal clearance

` No change in liver clearance



Perioperative concern

` Airway difficulty

` H/o OSA

` 1o or 2o

` End organ damage

` Drug interaction eg amphetamine



Difficult airway

` Desaturation- increase O2 demand, reduce FRC

` Difficult mask ventilation, difficult intubation

` Aspiration

` RSI with CP or awake fibreoptic



Predictors of difficult mask ventilation

` Overweight (BMI > 26)

` Beard

` Elderly (Age > 55 )

` Snoring

` Edentulous

` 5% incidence

` 2 factors predictiveO. Langeron et al Anesthesiology 2000;92:1229-36



Difficult intubation



OSA



ASA task force. Anesthesiolo 2006 104: 1081-93



STOP

` Validate OSA screening for surgical patients

` Concise, easy to use

`

Moderate high sensitivity & NPV

` > sensitive to moderate & severe OSA

Chung F et al. Anesthesiology 2008; 108: 812-21



STOP

` Snoring

` Tiredness

` O bserved apnea

` High BP` 2 yes : high risk for OSA



STOP



STOP BANG

` BMI > 35

` Age > 50

` Neck circumference > 40

` Gender - male

` High risk if yes 3



STOP BANG



Polysomnography

` Monitor ECG, EEG, EMG, oximetry

` Oronasal airflow with thermistor or pressure

transducer

` Respiratory effort via inductance or impedancepneumography and/or diaphragmatic EMG

` Body position

` LSAT

` Lowest SaO2 a/w abnormal respiratory event



Anaesthetic considerations

` Aspiration` Polycythemia

` Pulmonary hypertension

Pashayan AG et al. Anesthesiology Clin N Am 2005; 23: 431-43



Difficult intubation

` o difficult intubation in OSA(16.7% vs 3.3%)

` AHI higher in difficult intubation

(67.4 vs 49.9)

K im JA et al. Can J Anesth 2006; 53: 393-7

27.6% 19.3%

3.3%



Preop recommendations

` Pre procedure identification Of OSA status improves

outcome

` Preop CPAP

` Preop NIPPV, mandibular advancement, oral appliances

` Preop weight loss

OSA task force, Anesthesiology 2006; 104: 1081-93



Benefits of CPAP

` qAHI

` Improves O2 saturation

` q excessive daytime sleepiness

` q systemic hypertension

` Improves right heart failure

` Improves neurocognitive function.

Roop K et al. Chest 2006; 129: 198-205

Ryan F et al Am Rev Respir Dis 1991; 144: 939-44

Jain SS et al. Curr O pin Pulm Med 2004; 10: 482-8



Intraops

` Avoid sedative premed` Regional

` GA

` -RSI

` -awake fibreoptic intubation



Chung F et al. Anesth Analg 2008; 107: 915-20

Post op complications

` 27% vs 9%

` Respiratory most common

` 83% due to desaturation

` Incidence of post op complication

among patients with difficult airway

21%



Periop risk

`

Severity of OSA

` Invasiveness of procedure

` Requirements of postop analgesia

` PACU observation

ASA task force. Anesthesiology 2006; 104: 1081-93



postops

` adverse respiratory event` OSA, apnea, altered respiratory drive

` Rapid desaturation, difficult airway



monitoring

` -GICU` -anaes male oncall room

` -anaes female oncall room

` -anaes specialist oncall room



postops

` O2 supplement, CPAP` Opioid sparring, multimodal analgesia

` Pulmonary rehab

` DVT prophylaxis



Bariatric Surgery



Medical therapy

Combination of phentermine and fenfluramine (Phen-Fen) ² associated with valvular heart disease and pulmonaryhypertension; no longer approved by FDA

Sibutramine inhibits the reuptake of noradrenaline, serotonin,

and dopamine increase satiety after the onset of eating

Orlistat blocks digestion and absorption of dietary fat by bindinglipases in the GI tract



Types of surgery

Adjustable gastric banding.

A, Proximal pouch. B, Adjustable

band. C, Needle access port

through which saline is injected

or removed to vary the size of the

adjustable band.

Roux-en-Y gastric bypass.

A, A 15- to 30-mL gastric pouch with

connected jejunal limb. B, Site of

jejuno-jejunostomy



Anaesthesia` Considerations for obesity and its associated problems, in particular

` Airway considerations ² airway options

` Reflux / regurgitation ² acid aspiration prophylaxis

` Anaesthetic technique

` GA with endotracheal intubation ² RSI or awake FOB

` Usual considerations for laparoscopic surgery ² effects of pneumoperitoneum

on respiratory mechanics & CVS

` Postoperative management

` Consider HDU/ICU management especially if significant co-morbidities or h/o

OSA

` Postoperative pain management



Complications

RYGB anastomotic leak

gastric pouch outletobstruction

jejunostomy obstruction gastrointestinal (GI)

bleeding

wound infection

dumping syndrome protein-calorie

malnutrition

More common after openRYGB

AGB band erosion

erosive oesophagitis

herniation of the stomach

upward inside of the band band migration

disconnections at theportal site between thetube and reservoir



summary



Perioperative concern for obese pt

` Airway difficulty

` H/o OSA

` 1o or 2o

` End organ damage

` Drug interaction eg amphetamine



Obesity

` n=6336

` Multivariate regression analyses

` Obesity was not a risk factor for development of postop complications

Dindo D et al. Lancet 2003; 361:2032-5



STOP BANG or ASA

` Screening:` Obes, difficult airway

` All patients

` Risk and benefit of proceed



Periop risk

`

Severity of OSA` Invasiveness of procedure

` Requirements of postop analgesia

` PACU observation

ASA task force. Anesthesiology 2006; 104: 1081-93



Anaesthesia` Considerations for obesity and its associated problems, in particular

` Airway considerations ² airway options

` Reflux / regurgitation ² acid aspiration prophylaxis

` Anaesthetic technique

` GA with endotracheal intubation ² RSI or awake FOB

` Usual considerations for laparoscopic surgery ² effects of pneumoperitoneum

on respiratory mechanics & CVS

` Postoperative management

` Consider HDU/ICU management especially if significant co-morbidities or h/o

OSA

` Postoperative pain management



references

` Sharmeen Lotia and Mark C. Bellamy, Anaesthesia and morbidobesity Contin Educ Anaesth Crit Care Pain (2008) 8(5): 151-156

` Gerges FJ. Anesthesia for laparoscopy: a review. J Clin Anesth

2006; 18: 67-78

`

ASA task force Anesthesiology 2006; 104: 1081-93` Chung F et al. Anesthesiology 2008; 108:812-21

obesity, osa and bariatric surgery

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