WHAT IS OBESITY
• It is second only to smoking as a preventable
cause of death.
• Defination - obesity can be defined as a
disease because it a physiological dysfunction
of the human organism with genetic,
environmental, and endocrinological cause.
WHEN DOES OBESITY DEVELOPE
• When the calorie intake exceeds the energy
expenditure over a long period of time.
• Factors influencing- genetic, behavioral,
cultural, socioeconomic and metabolic.
• Ex- leptin deficiency, Prader Willi syndrome
HOW TO MEASURE OBESITY
• BMI= Wt(kgs)/ Ht 2 (m)
• Waist circumference.
OBESE CLASS 1
< 102 CM
< 88 CM
> 88 CM
INCIDENCE OF HEALTH RISK
TYPE 2 DIABETES
BMI> 25, 5X OBESITY
CAD AND STROKE
3.6X OBESITY, 70% LVH, 10% CCF,
NECK CIRCUMFERENCE >43(m), > 40.5(F)OSA, DAYTIME SOMNOLENCE, PUL HTN
ENDOMETRICAL Ca, 10% CANCER DEATHS
6% INFERTILY(F), IMPOTENCY (M)
LIVER AND GALL BLADDER DISEASE
NAFLD & NASH, 20% DYSLIPEDEMIA
ATHEROGENIC DYSLIPIDEMIA (TG, HDL, APO B)
ELEVATED BLOOD PRESSURE
INSULIN RESISTENCE WITH OR WITHOUT GLUCOSE INTOLERENCE
OTHERS ( endocrinological dysf, microalbuminuria, pcod, hypoandrogenism,
Comman in men, > 60, south asians, drugs- corticosteroids, SSRI, antidepressants
• Inflammatory response plays an important role in
• Visceral adipose tissue is a major source of
proinflammatory cytokines- TNF-a, IL-6, adiponectin.
• raised levels of proinflammatory cytokines contribute
to insulin resistance.
• Adipokines- leptin is reduced which results in increased
appetite , slow metabolism and susceptibility to
proinflammatory stimuli. They also contribute to
progession of heart disease and DM in obese patients.
EFFECTS ON RESPIRATORY SYSTEM
• Fat accumulation on the thorax and abdomen decreases chest wall and
• Increase in blood volume as more volume is required to perfuse the
additional body fat. Polycythemia of chronic hypoxemia contributes to
increased total blood volume.
• Increased elastic resistance and decreased compliance of the chest wall
further reduces total respiratory compliance while supine, leading to
shallow and rapid breathing, increased work of breathing,
• Respiratory muscle efficiency is below normal in obese individuals.
• Decreased pulmonary compliance leads to decreased functional residual
capacity (FRC), vital capacity, and total lung capacity. Residual volume and
closing capacity are unchanged.
• Reduced FRC Leads to small airway closure, ventilation-perfusion
mismatch, right-to-left shunting, and arterial hypoxemia.
• Anesthesia worsens this situation such that up to a 50% reduction in FRC
occurs in the obese anesthetized patient compared with 20% in the
• ERV is the most sensitive indicator of the effect of obesity on pulmonary
OSA/ OSH SYNDROME
• Characterized by recurrent episodes of upper
respiratory obstruction occurring during sleep.
• OSA- complete cessation of airflow during
breathing lasting 10sec or longer despite of
maintenance of neuromuscular ventilatory
efforts and occurring 5times or > during sleep,
decrease of Sao2 of atleast 4%.
• OSH- partial reduction of airflow of > 50%
lasting for 10sec, occurring 15 times or more/
hour of sleep and associated with decrease
Sao2 of atleast 4%.
MILD DISEASE -
AHI 5-15 EVENTS/ HOUR
MODERATE DISEASE- AHI 15-30 EVENTS/ HOUR
SEVERE DISEASE- AHI . 30 EVNTS/ HOUR
RISK ASSOCIATED WITH MODERATE AND SEVERE
DISEASE systemic and pulmonary HTN, LVH, cardiac
arrhythmias, cognitive impairment, presence of daytime
• Adipose tissue in oral and pharnygeal tissues.
• Increased fat deposition in the lateral walls
decreases the size of the airway and changes the
shape of the oropharynx – ellipitical, short
transverse and long AP diameter.
• Makes mask ventilation and laryngoscopy difficult
• Contributes to increased severity of airway
obstruction during GA
• airway obstruction after Extubation increases
with the use of opiates and sedative drugs .
• It is necessary to diagnose and treat OSA
• T/T- CPAP, conservatively- weight reduction ,
avoidance of alcohol intake before bedtime
,and sleeping on one side.
MANAGEMENT OF OBESITY
• NON – SURGICAL
1. Daily exercise for 30min
2. Statins- to reduce LDL
3. Statins and ezetimide ( inhibits interstinal
absorption of cholesterol)
4. Fibrates- decrease triglycerides and increase
5. Omega-3 fatty acids- decrease TG & insulin
6. Salt restriction- HTN+ Obesity+ metabolic
Drugs- BMI> 30
• PHENTERMINE- adrenergic
decreases appetite and food
intake , increases RMR. S/Etaccy, HTN
• SIBUTRAMINE- adrenergic
and serotninergic agent
which supresses appetite &
S.E- htn, taccy, dry mouth,
• ORLISTAT- binds to lipase
and prevents both
absorption and digestion of
dietary fats. S/E- prevents
absorption of fat sol
incontinence, oily recal
• BARIATRIC SURGERIES- surgical alterations of
the small intestine or stomach with a view
towards producing weight loss
• RESTRICTIVE- decreases the capacity of food
intake by creating a small pouch in proximal
part of stomach. Vertical band gastroplasty
and laparoscopic gastric band
• MALABSORPTIVE – gastric bypass and
Uncontrolled severe OSA
Drug abuse and malignancy
PREOPERATIVE EVALUATIONo Assessment of HTN, DM, heart failure, OSA
o Examination of history of previous surgery,
their anesthetic challenges, need for ICU
admission, surgical outcome and weight of the
pt at that time.
• FBS, lipid profile, CBC, ferritin, vit B12,
thyrotroin and 1,25-dihydroxyvitamin D
• Screening for OSA
• LFT- NAFLD, NASH,( portal HTN & Cirrhosis is
considered as C.I)
• Patient positioning- rhabdomyolysis from
pressure on the gluteal muscles RF & Death
• Cushioning gel pads, wt bearing rolls
• Pressure points should be adequately padded
• Axillary roll – pts with excessive axillary tissue
• Minimize compression injury or development
of compartment syndrome.
• Difficulty in ventilation and laryngoscopy short thick
neck, large tongue, redundant pharyngeal soft tissue.
• Assessing –MP, TMD, Neck circumference, MO, neck
mobility, USG-pretracheal soft tissue.
• Placing the patient in semirecumbent position (30D)
elevation with the head in sniffing position, ramped
positioning & head elevation.
• Minimized- awake intubation, topicalized direct
laryngoscopy with modest sedation, sedated fiberoptic,
( LMA, Fiberoptic shd be available in case of
• Low VC, inspiratory capacity, ERV, FRC, CC may
fall in supine or recumbent position rapid
• Application of CPAP (8-10cms H2O)during
preoxygenation & PEEP & mechanical
ventilation after induction is advised.
• To avoid desaturation & atelecatsis/ increase
airway pressure- 30 D reverse trendelenburg
Maneuvers to maintain lung vol and
• Increasing TV- 13-22ml/kg
• PEEP- 10 cm
• Lap surg- sustained lung inflation to 50cms
H2O & PEEP 12cms increase Pao2
• Extubation- adequate muscle strength,
sustained tetanus NS, 5sec head lift, awake
following commands can be extubated.
CPAP/Pressure support can be applied.
• Sedatives, opioids, benzodiazepine decrease the
pharyngeal musculature tone
• Volatile agents- diminish the ventilatory response
to CO2 .
• there is increased volume of distribution of
lipophilic drugs( benzodizepines, barbiturates)
• Dosing of the commonly used drugs like propofol,
vec, rocuronium,remifentanyl- IBW &
thipopental, midaz, scholine,atra, cisarta,
fentanyl, sufentanyl- TBW
• Thiopental. Prolonged somnolence with thiopental is expected
because it is highly lipophilic and has a larger VD in the obese
• Propofol. There is no difference in initial VD between obese and
nonobese patients with propofol.Propofol has high affinity for
excess fat and other well-perfused organs.
• Benzodiazepines. Benzodiazepines persist long after
discontinuation because they are highly lipophilic drugs with a
larger VD in obese patients. Midazolam, although considered short
acting, has the potential for prolonged sedation in obese patients
because larger initial doses are required to achieve adequate serum
• Neuromuscular Blocking and Reversal Agents. Pseudocholinesterase
activity increases linearly with increasing weight and larger
extracellular fluid compartment; therefore, the dose of
succinylcholine should be increased somewhat. Nondepolarizing
muscle relaxants should be administered according to LBW to
prevent delayed recovery because of increased VD and impaired
hepatic clearance. Prompt early reversal but slow full recovery has
been documented in overweight and obese patients during
neostigmine-induced reversal of vecuronium.
• The choice of volatile agents is based on tissue
solubility, blood gas partition coeff, fat- blood
• Desflurane is the agent of choice or
• Nitrous oxide is avoided as these patients
have more o2 demand, in lap surgery can
increase bowel gas volume & make the
procedure more challenging.
• Obese patients have a risk of aspiration due to
delayed gastric emptying.
• Prophylaxis for acid aspiration is required.
• Regional anesthesia is a safe option in such
patients but it is technically more difficultlarger needles or USG guidance.
• Care should be taken regarding the dose as
there can be cephalad spread of the drug and
block( smaller epidural space).
• Monitoring- no invasive monitoring is required
unless the patient is suffering from any comorbid
• In conditions like obesity-hypoventilation
syndrome with PHT- PA catheter or TEE.
• For ease of peripheral access – USG guidance or
CVC can be used.
• For NIBP-adequate sized cuff shd be available/
arterial catheter can be placed.
• Intra-op ABG analysis- guidance for I/O
ventilation and extubation.
• Appropriate sized table availability.
• Strapping the patient during sedation and sleep
• Placing a bean bag under the patient to keep the
patient from sliding.
• Armboards should have extra padding.
• Thermal management- warmers.
• Fluids- greater requirement, 4-5L of crystalloids
may be needed to prevent ATN.
EXTUBATION & TRANSPORT
• The patient should be preferably extubated in the
semirecumbent position, which has less adverse effect on
• Supplemental oxygen should be administrated after
• Lifting devices such as the HoverMatt (Patient Handling
Technologies, Allentown, PA), the Patient Transfer Device
(PTD; Alimed, Dedham, MA), and gantry-style mechanical
lifting devices that use a sling are useful for transporting
morbidly obese patients onto or off the operating table.
• The PTD can be combined with the Walter Henderson
Maneuver to safely and gently transfer obese patients onto
their postoperative beds.
Post-op pain management
• IV- analgesia via PCA
• Thoracic epidural
• Local anesthetic infilteration in the wound
with adjuctive non- narcotic medication.
Post operative management
• Bariatric patients should stay at the same location
• They are maintained on CPAP/ biphasic positive
airway pressure machines as much as possible
with monitoring of SpO2.
• Patients with difficult intubation should have a
labeled armband , a note by the attending
anesthesiologist explaining the difficulty in
intubation and equipements to tackle difficult
airway should be kept ready.
• Bariatric surgeries are considered to be safe
• Mortality is associated with intestinal leakage,
Intra abdominal bleeding, suture line
dehiscence, small bowel obstruction & deep
• Categorized- wound, GIT, pulmonary and CVS
• Complications are considerably lesser in
laparoscopic than open surgeries.
• Pul embolism and DVT
Leak from site
Fat soluble & vit