Obesity & anesthesia

Dr.Saad Al-Shamma

MBChB,DA,CABA&IC

Department of Anesthesia

Al-Yarmouk Hospital

Overweight and obesity are defined as abnormal or excessive fat accumulation that presents a risk to health.

A-Body mass indexBMI=WT(kg)/HT(cm)^218.5-24.9 NR25-29.9 Overweight30-34.9 class 1 obesity35-39.9 class2 obesity40-49.9 class 3 obesity>50 superobese

B-Brocas indexWt=ht-100(in males)or ht(cm)-105 (infemales)

Pathogenisis

Multifactorial

1-E intake>E expenditure

(if 2% increase then body wtincrease by2.3 kg in 1 yr

2-genetic

>41 obesity related gene

-high caloric diet+sedentary life style.

To maintain body wt after a period of wt loss we need to decrease E intake by 15%.

-At 2008 the WHO estimates that at least 500 million adults (greater than 10%) are obese, with higher rates among women than men.

-In basrah a study of 29,107 adult found 55.1% (overall obese &overweight)

23.8% obese

Women>men

Any 3 of the following:

-Complete cessation (or>50% decrease in hypopnea)of airflow lasting=>10sec despite maintainance of nr N-M ventilatory effort occuring >=5/hr associated with >=4% decrease in SaO2.

-Dx:polysomnograghy (EEG,ECG,EOG,EMG,oral or naso-

pharyngeal airflow,SaO2,BP,esophageal tonometry,room noise)

-Apnea/hypopnea index(AHI)=No. of episode/sleep time

OSAHS severity depend on AHI 5-15/hour mild 15-30/hour moderate >30/hour severe

One study of 170 obese pt where 15% are previosly Dx as

OSAHS,preoperative testing showed 76% to be OSAHS

Non-surgical manegement-therapeutic life style change(diet,exercise(>30 min/d),quit smoking)-behavioral modification-pharmacotherapy:Indicated to help wt lossif BMI>30 or >27 with comorbidity hpt ,dm, hyperlipidemia)FDA liecenced:Phenteramine(Adipex-P):adrenergic reuptake inhibitor ,appetite suppressantandincrese BMR,S,E,increase HR,HPT(max.12 weeks therapy),sibutramine(MEREDIA):inhibit reuptake of dopamine serotonine & NA ,decrease appetite &is thermogenic,orlistat(xenical):lipase inhibitor(decrease fat absorption,SE steatorhea,flatulence)Herbs(chitosan,ephedra ma huang,…etc)_

Requirement 1. AGE: 18 years of age or older.

2. BMI: Body Mass Index (BMI) between 40 and 60;

or Body Mass Index (BMI) of 35 or greater with significant co-morbid coinditions such as diabetes mellitus, sleep apnea, high cholesterol, the metabolic syndrome or infertility.

3. PHYSICIAN or PROFESSIONALLY SUPERVISED WEIGHT LOSS PROGRAMS: The patient must have made a significant effort at weight loss by participating in Physician or Professionally supervised weight loss programs over a prolonged period of time and failed to have achieved sustained weight loss.

1-unstable angina

2-ca with life expectancy<5 yrs

3- psychiatric disorder,mentalretardation(IQ<50).

4-Patient not able to cooperate or understand the complication of surgery

A-restrictive1-vertical band gastroplasty

2- laproscopic adjustable gastric band

B-malabsorptive

1-Roux-en-y gastric bypass

2-billio-pancreatic diversion

Preanesthesia assessment

1-difficult intubation&/or ventilation

Difficult intubation neck circumference>40 cm or mallampati 3or 4

Pt with home cpap>10 usually have difficult mask ventiation

2-associated comorbidities

Hpt, DM ,OSAHS,heartproblems

Investigations

CBC,FBS,LFT,renalfunction,TFT,lipidprofile,vitamin B12,D

s.Ferritin

Cxr,echo,ECG,pulmonaryFT,sleep study

Premedication

Metoclopromide,protonpump inhibitor,sodiombicitrate

Thromboprophylaxis(LMWH,graded elastic stockings)

Avoid sedative

Monitoring Nibp:large cuff is needed

(should cover75% or entire arm)or use forearm cuff ,

IBP required in morbid oesity with severe cardiopulmonary disease CVP,PCWP,and intraop. ECHo may also be required

N-m monitoring Special operating table

capable of holding up to 455 kg instead of 205kg for regular table

Intubation with fiberopticbronchoscope in selected patients.

Ramped position: to keep ears level with sternum

If needed 25-30% head up Pre-oxygenation+cpap(10-12

cm h2o or a value equal to the level used by the patient)

10-12 cm peep.recruitmentmethod is required.

Extubation is done head up awake fully reversed m.r

Cpap is continued in the early postop period

The ideal intraoperativeventilation strategy in obese patients remains obscure. There is some evidence that RM added to PEEP compared with PEEP alone improves intraoperative oxygenation and compliance without adverse effects. There is no evidence of any difference between PCV and VCV.

Recruitment method

40cm of water for 40 second

Or

40 cm of water for 10 sec repeated 4 times

Pain control Nsaid Iv Pca : using ideal body

wieght for opiod dosing,thoracic epidural pca

-Local infiltration of the wound with long acting la+nsaid(eg.paracetamolvial)+opiod pca is reasonable approach for most patients

Or dexmedetomedineinfusion +opiod pca