[ ] Anesthesia for Bariat

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[ ] Anesthesia for Bariat

  1. 1. Anesthesia for Bariatric Surgery By: Vladimir Melnikov MD UT Dept. of Anesthesiology
  2. 2. Anesthesia for Bariatric Surgery <ul><li>Obesity affects millions of persons in the USA and around the world </li></ul><ul><li>In 1990 $46 billion - 6.8% of all health care costs- was spent on obesity related problems in the USA. </li></ul><ul><li>Current estimates exceed $100 billion </li></ul><ul><li>The precursors to obesity include </li></ul><ul><li>1.Genetic tendency </li></ul><ul><li>2.Environmental effect. </li></ul><ul><li>3.Education </li></ul><ul><li>4.Gender, ethnicity </li></ul><ul><li>5.Socioeconomic </li></ul>
  3. 3. Anesthesia for Bariatric Surgery <ul><li>Medical co-morbidities associated with obesity </li></ul><ul><ul><ul><ul><li>NIDDM </li></ul></ul></ul></ul><ul><ul><ul><ul><li>HTM </li></ul></ul></ul></ul><ul><ul><ul><ul><li>CV DISEASES </li></ul></ul></ul></ul><ul><ul><ul><ul><li>OSA </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Liver & Gallbladder diseases </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Arthritis </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Colon and postmenopausal breast cancer </li></ul></ul></ul></ul><ul><ul><ul><ul><li>The risk of dying prematurely increases </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Quality of life issues: depression, social incompetence, etc. </li></ul></ul></ul></ul>
  4. 4. Anesthesia for Bariatric Surgery <ul><li>Bariatrics is the field of medicine that specializes in treating obesity. </li></ul><ul><li>Bariatric surgery is a surgical subspecialty that perform operations to treat morbid obesity. </li></ul><ul><li>Most of the patho-physiology & medical conditions associated with extreme Obesity are reversible with sustained weight lose following Bariatric surgery. </li></ul><ul><li>Over 100,000 laparoscopic Bariatric procedures were performed in the US in 2004. </li></ul><ul><li>Mortality rate for Bariatric surgery is 0.5% - 1%! </li></ul>
  5. 5. Anesthesia for Bariatric Surgery <ul><li>Definitions. </li></ul><ul><li>A person is considered obese when the </li></ul><ul><li>amount of body fat increases beyond the </li></ul><ul><li>point where health deteriorates and life </li></ul><ul><li>expectancy is shortened. </li></ul><ul><li>Two general types of obesity </li></ul><ul><li>1.Central-andriod Obesity associated with metabolic </li></ul><ul><li>syndrome </li></ul><ul><li>2.Periferal-gynecoid Obesity. </li></ul>
  6. 6. Anesthesia for Bariatric Surgery <ul><li>Body Mass Index = weight/height x height </li></ul><ul><li>BMI = 25 – NORMAL </li></ul><ul><li>BMI>30 – OBESE </li></ul><ul><li>BMI>40 OR > with medical co-morbidity – Morbidly obese </li></ul><ul><li>Ideal Weight = Height - 100 </li></ul>
  7. 7. Anesthesia for Bariatric Surgery <ul><li>PREOPERATIVE EVALUATION </li></ul><ul><li>1. CV & RESPIRATORY SYSTEMS </li></ul><ul><li>a) Tolerance of exercise and ability to lie flat. </li></ul><ul><li>b) Symptoms of sleep apnea should be sought. </li></ul><ul><li>2. Airways. Number of abnormalities may exist </li></ul><ul><li>a) Limitation of extension and flexion of the C-spine. </li></ul><ul><li>b) Restricted mouth opening from submental fat. </li></ul><ul><li>c) Large tongue. </li></ul><ul><li>d) Redundant intra oral tissue. </li></ul><ul><li>e) Thyromental distance should be assessed. </li></ul><ul><li>f) Infantile type anterior laryngeal opening. </li></ul><ul><li>3. Use of diet tablets (some of them cause valvular regurgitation or </li></ul><ul><li>pulmonary HT). </li></ul>
  8. 8. Anesthesia for Bariatric Surgery <ul><li>PREOPERATIVE EVALUATION </li></ul><ul><li>4. Obesity Hypoventilation Syndrome. Pickwickian syndrome: </li></ul><ul><li>Obesity, excessive daytime sleepiness, snoring cor Pulmonale. </li></ul><ul><li>a) Hypercapnia </li></ul><ul><li>b) Severe hypoxemia </li></ul><ul><li>c) Periodic breathing </li></ul><ul><li>d) Biventricular enlargement (RT>LT) </li></ul><ul><li>e) Dependent edema. </li></ul><ul><li>f) Polycythemia. Pulmonary edema. </li></ul><ul><li>5. Metabolic Changes </li></ul><ul><li>Patient scheduled for surgery following previous Bariatric surgery may have chronic metabolic changes. </li></ul>
  9. 9. Anesthesia for Bariatric Surgery <ul><li>PREOPERATIVE EVALUATION </li></ul><ul><li>CV Systems. </li></ul><ul><ul><li>The degree of cardiac abnormality is correlated with the degree of obesity. </li></ul></ul><ul><ul><li>LV dysfunction is often present in young asymptomatic patient </li></ul></ul><ul><ul><li>HTN </li></ul></ul><ul><ul><li>Increased Pre-load & After-load </li></ul></ul><ul><ul><li>Increased PAP (dyspnea, fatigue, syncope). </li></ul></ul><ul><ul><li>Pulmonary System. </li></ul></ul><ul><ul><li>O2 consumption & CO2 production increased </li></ul></ul><ul><ul><li>WOB increased </li></ul></ul><ul><ul><li>Chest wall compliance & FRC are low. </li></ul></ul>
  10. 10. Anesthesia for Bariatric Surgery <ul><li>PREOPERATIVE EVALUATION </li></ul><ul><li>GI System. </li></ul><ul><ul><li>No difference in gastric volume or PH between lean and obese surgical patient. </li></ul></ul><ul><ul><li>NIDDM and Gastroparesis. </li></ul></ul><ul><ul><li>Fatty Liver w or w/o liver dysfunction is common. </li></ul></ul><ul><ul><li>Gall bladder disease is also common. </li></ul></ul>
  11. 11. Anesthesia for Bariatric Surgery <ul><li>ANESTHETIC CONSIDERATIONS </li></ul><ul><li>PREMEDICATION </li></ul><ul><ul><li>Avoid heavy sedation. </li></ul></ul><ul><ul><li>Medication for chronic HTN </li></ul></ul><ul><ul><li>No diabetic medication on the morning of surgery </li></ul></ul><ul><ul><li>Antibiotics & heparine prophylaxis </li></ul></ul><ul><ul><li>H 2 antagonist, metoclopramide? </li></ul></ul><ul><li>Monitoring </li></ul><ul><ul><li>NIBP can be obtained from the wrist or ankle. </li></ul></ul><ul><ul><li>A-line highly recommended. </li></ul></ul><ul><ul><li>CVP or PA lines? </li></ul></ul><ul><ul><li>Nerve stimulator: needle electrodes are recommended (surface electrode </li></ul></ul>
  12. 12. Anesthesia for Bariatric Surgery <ul><li>Pharmacological Considerations </li></ul><ul><ul><li>Drugs are often administered on the basis of dose per unit body weight. </li></ul></ul><ul><ul><li>This assumes that clearances and distribution volumes are proportional to weight. </li></ul></ul><ul><ul><li>The assumptions 1&2 are not valid for obese patients. </li></ul></ul>
  13. 13. Anesthesia for Bariatric Surgery <ul><li>Induction Agents </li></ul><ul><li>Larger than usual doses of Propofol or Thiopental are needed due to increased blood volume & CO. </li></ul><ul><li>Muscle Relaxants </li></ul><ul><li>Higher doses of succinylcholine 1.5mg/kg IW are used. </li></ul><ul><li>Neuromuscular recovery time is similar in obese & non-obese patient with CIS-ATRACURIUM (NIMBEX) </li></ul><ul><li>Complete paralysis is especially important during laparoscopy. </li></ul><ul><li>Neuromuscular blockade must be completely reversed before extubation. </li></ul><ul><li>OPIOIDS. </li></ul><ul><li>There is no evidence that lipophilic opioids last longer in morbidly obese patient. </li></ul>
  14. 14. Anesthesia for Bariatric Surgery <ul><li>TRACHEAL INTUBATION </li></ul><ul><ul><li>Increasing weight or BMI is not a risk factor for difficult laryngoscopy. </li></ul></ul><ul><ul><li>FOB intubation is rarely necessary. </li></ul></ul><ul><ul><li>Rapid induction with Propofol &Succinylcholine is the best for establishing an airway. </li></ul></ul><ul><ul><ul><ul><li>Since mask ventilation can be difficult a second person experienced with airway management should be present to assist. </li></ul></ul></ul></ul><ul><ul><ul><ul><li>LMA should be available and can serve as abridge until an ETT is placed. </li></ul></ul></ul></ul>
  15. 15. Anesthesia for Bariatric Surgery <ul><li>VENTILATION </li></ul><ul><li>VT – 10-12ML/KG IW </li></ul><ul><li>FiO 2 up to 1.0 may be needed </li></ul><ul><li>High PiP will be needed </li></ul><ul><li>PEEP = 5cm H2O </li></ul><ul><li>N2O is avoided </li></ul><ul><li>Pneumoperitoneum can displace diaphragm causing the ETT to enter bronchus. </li></ul><ul><li>HEMODNAMIC CHANGES </li></ul><ul><li>The RTP may cause pooling of blood and hypotention. </li></ul>
  16. 16. Anesthesia for Bariatric Surgery <ul><li>ANESTHETIC TECHNIQUE. </li></ul><ul><ul><ul><li>OPIOIDS I>V> CONTINUOS INFUSION. </li></ul></ul></ul><ul><ul><ul><li>CISATRACURIUM I.V. CONTINUOS INFUSION. </li></ul></ul></ul><ul><ul><ul><li>INHALATION ANESTHETIC DEFLURANE. </li></ul></ul></ul><ul><ul><ul><li>POSTOPERATIVE CONSIDERATIONS. </li></ul></ul></ul><ul><ul><ul><li>Position: Upper body elevated 30-45 degree. </li></ul></ul></ul><ul><ul><ul><li>Oxygenation: Restoration of normal pulmonary function after abdominal surgery may take several days. </li></ul></ul></ul><ul><ul><ul><ul><ul><li>Nasal or mask O2. </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Nasal CPAP </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>BiPAP </li></ul></ul></ul></ul></ul><ul><ul><ul><li>Analgesia: </li></ul></ul></ul><ul><ul><ul><li>An opioid PCA dosed on the basis of IW </li></ul></ul></ul><ul><ul><ul><li>NSAIDs </li></ul></ul></ul>

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