obesity, harmful effects and associated risks.pptx

Obesity

1. Obesity with hypoventilation Dr. B.Manisha (PG-3) Department Of Anaesthesiology Kamineni Institute Of Medical Sciences 1

2. CASE A 57 year old male patient, smoker, H/O COPD, diagnosed with acute cholecystitis , posted for open cholecystectomy . His BMI is 38kg/m2. He is treated for OSA with BiPAP with pressure 10cm of H2O insp / 7cm of H2O exp for past 7 years . 2

3. PAST HISTORY Patient is a k/c/o OSA being treated with bipap . No associated comorbidities Not a K/C/O diabetes, hypertension, asthma, tuberculosis, epilepsy, jaundice. No past surgical history No history of any bleeding tendencies 3

4. PERSONAL HISTORY Pt is non vaishya . Smoker since 20 years, 15cigarettes/day . Last smoked 3years back. 3 0Packyears Occasional alcoholic since 10years, last taken 2months back. Has H/O snoring, choking at night . No h/o breathlessness (METS>4 ) No H/O cough, cold Two doses of covid vaccination taken Bowel and bladder movements regular Mixed diet 4

5. CLINICAL EXAMINATION Pt is obese built , hydrated Wt:108kgs Ht:168cm BMI:38.3kg/m2 No signs of pallor ,cyanosis , clubbing, pedal oedema, ascites. On airway examination— Bilateral nares patent Normal cervical spine movement. Normal TMJ movement, short neck+ No visible neck swelling Trachea is central in position Hygenic oral cavity . 5

6. No loose/ protruding/ missing teeth > 3finger breadth mouth opening Mallampati grade I On spine examination-normal VITALS :patient was conscious, coherent, cooperative, well oriented to time, place and person. Blood pressure-120/80 mm of hg Pulse rate-84 bpm,regular in rhythm , normal in volume Respiartory rate: 12cpm Spo2: 97% on room air Temperature: afebrile CVS-S1 & S2 heard RS- Bilateral air entry present, clear. 6

7. INVESTIGATIONS COMPLETE BLOOD PICTURE Hemoglobin – 11.9g/dl Total leucocyte count-10,300 cells/cu mm Platelet count-3.6 lakhs Blood group – “B” POSITIVE Bleeding time – 2min 00sec Clotting time – 4min 30sec PT – 16sec APTT – 31sec INR – 1.11 RBS: 128mg/dl COMPLETE URINE EXAMINATION: urine albumin+ Urine sugars- nil 7

8. LIVER FUNCTION TEST Total bilirubin-1.35mg/dl Direct bilirubin-0.28mg/dl AST-34 IU/L ALT – 51 IU/L ALP- 140 IU/l Total Proteins – 7.6 gm /dl Albumin-4.6 gm /dl A/G ratio – 1.56 RENAL FUNCTION TEST UREA- 20 mg/dl CREATININE – 0.8 mg/dl URIC ACID – 5.9 mg/dl SODIUM-139 mEq /L POTASSIUM – 4.2 mEq /L CHLORIDE – 99 mEq / L CALCIUM (ionized)- 1.06 PHOSPHOROUS – 3.1 mg/dl 8

9. ECG 9

10. ABG on room air: PH:7.35 PO2:80mmhg Pco2:45mmhg Hco3-:25mmol/L

11. Case was taken under ASA grade 3 PRE-OP VITALS : at 8:30am BP: 120/70 mm Hg PR: 110bpm Spo2: 97%on RA Grbs:110mg/dl CVS: S 1 & S 2 heard, no murmur RS: B/L air entry present and clear, no added sounds. I.V Line: 18G IV cannula secured and fixed on the dorsum of left hand. 12

12. Patient was shifted to Operation Theatre by 9.10am ANTICIPATED DIFFICULT INTUBATION WAS expected; and RAMP Position was kept. PREMEDICATION INJ. G L YCOPYRROLATE 0. 2 mg IV INJ. ONDANSETRON 4 mg IV INJ. MIDAZOLAM 1 mg IV INJ. FENTANYL 100 mcg IV Induced with INJ. PROPOFOL 150 mg IV Intubation was done using INJ. Succinylcholine 100 mg IV at 9:30 am 13

13. Intubation done, it was cormack lehanne grade 2b; was able to pass bougie with 7 mm ENDOTRACHEAL TUBE fixed @ 20 cm lip mark. At 9.45 am Confirmed by 5point auscultation and capnography . Ryles tube was inserted INJ. HYDROCORTISONE 200mg IV 14

14. VENTILATOR SETTINGS: mode: volume controlled ventilation Tidal Volume: 6ml/kg Respiratory rate: 12-16cpm PEEP: 10cmH2O, I:E ratio- 1:3 Maintainance : MUSCLE RELAXANT: loading dose: Inj . VECURONIUM 6 mg IV given followed by 9mg given intermittentl y at intervals. ISOFLURANE at 0.5-1.5%; Blood loss: 30 0ml ; urine output: 500ml 15

15. TIME BLOOD PRESSURE PULSE RATE SPO2 ETCO2 9AM 120/80 88 100 - 9.30AM (at the time of intubation) 150/95 95 100 30 10AM 145/90 92 100 42 10.30AM 140/95 90 99 44 11AM 130/85 86 100 49 11.30AM 120/75 82 100 47 12PM 118/70 80 100 45 1PM 110/68 82 100 43 16

16. EXTUBATION: after thorough ryles tube,oral , and ET tube suctioning was done and after adequate eye opening, tongue protrusion, head lift, muscle power and tidal volume is attained REVERSAL: INJ. SUGAMMADEX 400mg IV given at 12:45 pm. Patient was hemodynamically stable and extubated at 1pm, and shifted to postop. POST OP vitals: at 1:20pm BP:130/90mmhg Pulse:88 bpm SPO2:99% with 6litres of 02 17

17. OBESITY Obesity Is defined as an abnormally high amount of adipose tissue compared with lean muscle mass (20% or more over ideal body weight ) Primarily induced and sustained by an over consumption or under utilization of caloric substrate. Genetic, behavioral, cultural and socioeconomic factors .

18. Cardiovascular system 21

19. RESPIRATORY SYSTEM Restrictive lung disease Obesity hypoventilation syndrome (OHS) Obstructive s leep apnea (OSA) Pulmonary Hypertension 22

20. RESTRICTIVE LUNG DISEASE FRC , ERV, TLC ---- v/q mismatch and arterial hypoxemia(low pao2) Right( deoxy ) to left(oxy) intrapulmonary shunting is seen. Closing capacity> FRC FRC decreases by 50% in obese under GA (20% in non obese patinets ) Low FRC- -- low O2 reserve- -- early desaturation during apnea BMI –-- raised metabolic rate in obese –-- increased O2 utilisation and co2 production –-- raised minute ventilation and work of breathing

21. Terms for describing pt’s weight:- Total body weight:- The actual wt. of the pt. Ideal body weight:- What the patient should weigh with a normal ratio of lean to fat mass. Calculated by Broca’s index IBW(kg )=Ht.(cm) – x (where x=105 in females and 100 in males). Lean body weight:- The pt’s wt. excluding fat. LBW(kg)= 9270 x TBW(kg) . ( 216 for men and 244 for women) 6680 +(216/244 x BMI (kg/m2) Adjusted body weight:- calculated by adding 40% of the excess weight to the IBW ABW(kg)= IBW(kg) + 0.4 {TBW (kg) – IBW (kg)} 28

22. Measuring Scales for obesity Body mass index ( Quetelet's index) = [ weight(kg)/height(m2)] 29

23. Other parameters: Waist circumference:- correlates with abdominal fat. High risk: Male > 102 cm, Female > 88cm. Waist to hip ratio:- High risk: >1 in males, >0.8 in females. 30

24. Obstructive sleep apnea Episodic Complete cessation of airflow lasting > 10seconds occuring for > 5 times /hour of sleep accompanied with decrease of atleast 4% in SaO2. Clinical sequelae such as hypoxia, hypercarbia , pulmonary and systemic hypertension, polycythemia, arrhythmias, ↑risk of IHD and stroke, corpulmonale . Diagnosis:- polysomnography (apnea-hypopnea index) Other parameters:- Total arousal index, Respiratory disturbance index Patients diagnosed to have moderate/ severe OSA have to undergo CPAP prior to elective surgery 31

25. Obesity hypoventilation syndrome / Pickwi c kian syndrome Results from long term OSA Combination of obesity and chronic hypoventilation that ultimately results in pulmonary hypertension and cor pulmonale . Diagnosis:- BMI >30kg/m2 and awake arterial hypercapnia (PaCO2 >45mm Hg) in the absence of known causes of hypoventilation . 32

26. Metabolic syndrome Diagnosis:- 3 of the following Abdominal obesity (Waist > 102 “ in males and > 88“ in females) Hypertension (>130/85 mm Hg) Triglycerides ( > 150mg/dl) HDL Cholestrol ( <40 mg/dl in males and <50 mg/dl in females) Impaired fasting glucose ( > 110 mg/dl) 33

27. ANESTHETIC MANAGEMNET

28. Preoperative considerations PAC:-evaluation of cardiopulmonary system: chest pain, dyspnea, palpitations, fatigue, syncope, h/o OSA. STOP BANG: Sleep Apnea questionnaire Snoring, Tiredness, Observed apnea, high blood Pressure, BMI >35, Age >50yrs , Neck circumference >40cm, Gender-male High risk of OSA: Yes 5 – 8 Intermediate risk of OSA: Yes 3 – 4 Low risk of OSA: Yes 0 – 2 Look for HTN/DM/CCF/pulmonary HTN/OSA Symptoms of acid reflux, coughing, if on any antacids?--- GERD 35

29. Concurrent, preoperative, and prophylactic medications Usual medications should be continued except insulin and OHA. Antibiotic prophylaxis For aspiration pneumonitis :- H2 receptor antagonists, nonparticulate antacids, proton pump inhibitors used. Nil by mouth – 12 hrs. Prophylaxis against DVT . Continue CPAP/ BiPAP overnight 36

30. INTRAOPERATIVE MANAGEMENT

31. Positioning Specially designed tables or two regular operating tables joined together Strapping obese patients to the operating table helps keep them from falling off the operating table. Protecting pressure areas - pressure sores, neural injuries. Arms to be kept in neutral position to avoid excess pressure from tight tucking and draping . Choice of anesthesia: Local or regional anesthesia>>> general anesthesia . Regional anesthesia: May be difficulty in finding landmarks. Engorged epidural veins and epidural fat constricting the potential space, 20% less local anaesthetic of the normal dose is needed. 38

32. GENERAL ANESTHESIA PREOXYGENRATION: 30% propped up position; with 100%FiO2, for 5-8mins with CPAP of 10cm H2O. PREMED: avoid benzodiazepines, Sedative-hypnotic in minimal doses Emergency airway cart should be kept ready If a difficult intubation is anticipated, awake intubation is a prudent approach. Sedation with Dexmedetomidine provides adequate anxiolysis and analgesia without respiratory depression. Hypoxia and aspiration of gastric contents should be prevented. Call for an experienced assistant. 39

33. RAMP (RAPID AIRWAY MANAGEMNT POSITION) To align oral/pharyngeal/laryngeal axis 40

34. Maintenance Continuous infusion of a short-acting intravenous agent, such as Propofol , Inhalational agents that are minimally metabolized are useful agents, with Desflurane possibly providing better hemodynamic stability and faster washout . Avoid N2O as it can worsen pulmonary hypertension Short-acting opioids , combined with a low-solubility inhalation agents, facilitate a more rapid emergence without increasing opioid-related side effects. Cis-atracurium possesses an organ-independent elimination profile and is a favorable NDMR for use during maintenance. Dexmedetomidin e with sedative and analgesic properties, is an attractive anesthetic adjunct in obese patients. 41

35. Highly lipophilic drugs - ---> increased Vd in obese pt. so drug doses are calculated on basis of TBW. ( eg thiopental, BZDs, propofol , fentanyl, Sch , dexmedetomidine , atracurium etc.) Weakly lipophilic drugs have unchanged Vd in obese pt. so drug doses are calculated on basis of LBW. ( eg alfentanyl , ketamine, morphine, vecuronium , rocuronium ).

36. Intra Operative Ventilatory Management Avoid lung overdistension Use tidal volume of 6-10 mL/kg of ideal body weight BMI >40 – use mean airway pressure 55cm H2O BMI <40– use mean airway pressure 40cm H2O. Use PEEP (10-12 cm/H2O ) Consider mild permissive hypercapnia if necessary Maintain lung recruitment: sigh/ valsalve /high tidal volume for 7-8sec 43

37. Monitoring For NIBP, larger bp cuffs should be used Invasive arterial pressure monitoring may be indicated for the morbidly obese, or if inadequate BP cuff. USG g uided Central venous catheterization may also be required for difficult intravenous access. Prophylactic IVC filter: high risk for DVT, PE Maintain normothermia For longer duration surgery/morbid obese : with pulmonary HTN, RVF: consider pulmonary artery catheter/ TEE. 44

38. EXTUBATION Patient should be fully awake, follow oral commands, have adequate muscle strength, Adequate tidal volume and airway reflexes. Neuromuscular monitoring for muscle strength Extubate in propped up >30 degrees position Shift to PSV+PEEP Placement of airway exchange cathetrer before extubation in high risk cases. Insert nasopharyngeal airway Supplemental oxygen should be administrated after extubation . 45

39. Management of postoperative pain In patients with obstructive sleep apnea – opioid sparing techniques help avoid respiratory complications. A multimodal approach is best. It include Peripheral and central nerve block with continuous infusion of LA + opioids NSAIDs , acetaminophen α 2 agonists, NMDA receptor antagonists(ketamine), sodium channel blockers Local anesthetics injected into the wound or port site, Recent technique is the continuous intraperitoneal infusion of bupivacaine .

40. There is an increased incidence of atelectasis in postoperative period. Initiation of CPAP ------>  FRC, improve lung compliance, improve ventilation & oxygenation, upper airway obst &  WOB early ambulation, deep breathing exercises, and incentive spirometry are all useful adjuncts. Pulse oximetry and ABG should be monitored appropriately. 47

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