Category Archives: MIS/Bariatric

Bariatrics

  • Candidates
    • BMI >35kg/m2 with comorbidity or body weight >80lbs above ideal body weight with co-morbidity
      • Co-morbidities: Htn, cardiovascular dysfunction, hlp, DM II, respiratory insufficiency, stress incontinence, gerd, carcinomas
    • BMI >40 or body weight >100lb above ideal body weight
    • Mortality 3x normal weight parallel
    • Considering BMI 30 with diabetes
  • Procedures: Restrictive, malabsorpitive, or a combination
  • Sleeve gastrectomy: ~40 fr bougie
    • Works by restriction and by rapid transit causing satiety
    • 75% resection of stomach: no bypass
      • Greater curvature of stomach is devascularized prior to resection
    • 60%excess wt loss at 3 years
    • Complications
      • Gastric Leak: most frequent complication 0.9%
      • Stricture, bleeding, PE, delayed gastric emptying, abscess, ssi, splenic injury trocar hernia
    • Revision rates 4%
  • Adjustable gastric banding
    • Silicone band around proximal stomach: dissection through fatty tissue posterior to GE Jxn and creation of a tunnel for the band
      • Pars Flaccida technique: reduces slippage to < 3%
      • Small proximal pouch
    • Fill band with fluid after 6wks
    • Outpt procedure but more f/u needed
    • Gradual lower weight loss: steady weight loss
    • A/e
      • Complication rate <1%, mortality < 0.1%
        • 30% long term reop
        • 20% failure rate
      • Slippage: obstruction, vomiting, epigastric pain
        • Can necrose fundus
      • Dilation of esophagus: >5cm need to empty band
      • Follow pt with barium swallow
      • Erosion: avoid nsaids
      • Perforation: often missed/late presentation
  • RYGB: Gastric Bypass
    • Restrictive and malabsorptive
    • 60ml proximal gastric pouch anastomosed to Roux limb, created 150cm from the ligament of treitz
      • Rou-ex-Y limb anastomosed to stomach pouch
      • 75-150cm alimentary limb
      • 50-100cm afferent limb
      • 10-15mm stoma not reinforced
      • No fundus included in pouch: important for outcomes (hormonal)
    • Hormonal changes in ghrelin, glucagon-like peptide-1, and peptide YY that influence eating behaviors and body weight.
    • Reduced bile and lipolytic enzyme secretion 2’ no duodenal activation
      • Delayed fat breakdown and micelle formation limits absorption. Can cx steatorrhea
    • Advantage
      • Mean EWL excess wt loss 60% at 12 mo
      • 80% at 24 mo
      • 75% at 30 months
      • Low failure rate
    • A/E
      • Operative 30 d mortality 0.1-0.5%
      • MC complication: dehydration
      • Malabsorption: difficult to reverse
        • Protein intolerance
        • Divalent cations: (absorbed in duodenum): iron calcium magnesium
        • Oral FeSO4 supplements decreases absorption of Ca, Mg, Zn
        • b12 (stomach antrum-intrinsic factor)
        • Supplementation necessary: Vit B, Ca, Vit D, Folate, Thiamine
        • Vit B deficiency: occurs > 1 year after operation
        • Macrocytic anemia and neuropathy
        • Vit D deficiency: fat sol vit: Loss of fat absorption dec vit d, higher bone turnover and dec bone mass
        • Follow pth, vit d, and ca levels
        • High PTH means low ca or vit d
        • Supplement with ergocalciferol
      • Leak 1-2%, revision 4-8%
      • Complications 2-5%
      • Death 0.5-1%
  • Biliopancreatic diversion
    • Greatest weight loss and most nutritional problems
    • 75% of stomach resected and bypass all but 250cm of small bowel
    •  Procedure
      • Sleeve gastrectomy: 60Fr bougie
      • Duodenum is divided 2 cm distal to the pylorus, preserving the blood supply and vagal innervation of the antrum.
      • A Roux limb is created by dividing the small intestine 250 cm proximal to the ileocecal valve and anastomosing this to the postpyloric duodenal cuff.
      • The bypassed biliopancreatic limb is sewn to the Roux limb 100 cm proximal to the ileocecal valve, creating the “common channel.”
    • Vs RYGB
      • More technically challenging
      • Large gastric capacity
      • less dumping syndrome
      • more effective in reversing DM, HLP, HTN in super obese bmi>50
      • >wt loss at 3 years in super obese
    • Not strictly malabsorptive
    • Hormone changes: specifically gastric bypass and sleeve gastrectomy
      • Induce satiety: L cells of lower gut: Increases in GLP-1 and PYY
      • GLP-1 released hindgut in increased amounts potent release of beta cell insulin release
      • Decrease in Ghrelin: proximal stomach and fundus
      • Normally: Arexogenic: induces hunger
      • Proximal small bowel will make up for some of the ghrelin
    • Mean excess weight loss after BPD > 70% in published series.
    • 30d operative mortality 0.5-1.1%
  • Jejunoileal bypass: not done
    • a/e bypass segment bacterial overgrowth and protein malabsorption leads to cirrhosis
  • Outcomes
    • Resolution of co-morbidities
    • DM 76% resolved
    • 2’ to calorie restriction (some part form glp-1)
    • Rapid wt loss 1lb/d.
    • Improved sensitivity to insulin
    • HLP 70% improved
    • Htn 61% resolve
    • Sleep apnea 85% resolved
  • Operative mortality <30d:
    • restrictive 0.1%
    • bypass 0.5%
    • biliopancreatic diversion 1.1%
  • General Rules
    • Postop: Can never smoke or take NSAIDS
    • Not normal to vomit after gastric bypass
    • Don’t give dextrose, give ns and thiamine
  • Early Complications
    • Pulmonary: apneic arrest, dvt/pe
      • Apneic Arrest- anesthetic in fat
      • Hypoventilation leading to resp/cardiac arrest
      • Incidence <2%
      • Prevention is key
      • Pre-op sleep apnea dx
      • Peri-op cpap: extremely important
      • Admit high risk pt to monitored setting
      • Limit narcotics
      • Signs: desat, somnolence, mental status changes
      • Tx: intubation
    • Dvt/pe
      • Incidence 1-2%, fatal pe 0.2%
      • Risk factor: obesity hypoventilation syndrome
      • BMI >55, male, lower extremity venous ulcer dz
      • No longer consider prophylactic insertion of filter
      • Tx: Heparin, ambulation, scds
      • Symptoms: diaphoresis tachycardia hyopxia
    • Enteric leaks
      • Incidence: 1-8% higher with revision
      • Possible locations
        • gastroJ
        • gastric pouch staple lines
        • remnant gastric staple line
        • J-Jostomy: typically high volume
      • Pt deteriorates rapidly
      • Technical issues
        • Missed perf: blind instrument insertion
        • Avoid devascularlizing the pouch/roux limb
        • Avoid tension
        • Ante colic: make a large groove in omentum
        • Retrocolic less tension
        • Consider longer pouch in super-morbidly obese
        • Test anastomosis
      • Presentation: not with peritonitis, can be insidious
        • Tachycardia: HR >120 (most sensitive)
        • Tachypnea, respiratory distress, hypoxia
        • Elevated wbc
        • Fever >101.5
        • Sever abdominal pain
        • Oliguria
        • Mental status changes
      • Dx
        • UGI series: routine use debatable, doesn’t evaluate anastomosis of gastric remnant or distal
        • CT
        • Exlap
      • Tx
        • Leak control and drainage
        • Supportive care
        • Iv ABx
        • Vent support-early trach
        • Beware decubiti
        • Nutrition: gtube preferred
        • Remnant decompression/enteral feeding
        • TPN
    • Small bowel obstruction
      • Early dx and or exploration to prevent acute gastric REMNANT distention
        • Hemorrhage
        • Early: intraluminal: staple line bleed: 50-70% stop spontaneously
        • Tx IVF and blood product resuscitation
        • a/e intraluminal blood can cause SBO: hemobezoar
      • Late
        • Peptic ulcer dz: bleeding ulcer in remnant
        • Marginal ulcers: 2’ to smoking or nsaid use
        • Dumping syndrome: post RYGBP: up to 70%
          • Early: 15 min pc: d/t sudden osmotic load in jejunum
          • isotonic fluid from plasma enters lumen: falls in BP
          • stimulation of argentaffin cells: release of 5HT: serotonin sy
          • Late phase: 1.5-3hr pc: hypoglycemia
          • High glycemic index food is rapidly absorbed:insulin spike: glucose and K shift intracellular
          • Tx: frequent dry meals, low carb, high protein, fluids between meals only
          • Reinforces correct eating behavior
      • Rhabdomyolysis
        • 2’ muscle compression during surgery (concern >4hrs)
        • Labs: Hyperkalemia, hypocalcemia, hyperphosphatemia, hyperuricemia, acidosis, aki, dic, compartment syndrome
        • Cpk >5x nml, peaks 4-7 d. remains elevated 12 days
        • Urine myoglobin
        • Sx: pain, tenderness, swelling, bruising weakness
          • Dark uring, fever, malaise, confusion
        • Imaging: hyperechoic skeletal muscle on U/s
          • CT: muscle necrosis/ calcification
          • MRI: muscle edema
        • Tx
          • IVF: > 1.5 ml/kg/hr
          • Mannitol
          • Sodium bicarb pos: can accelerate ca/po4 deposits in tissues
          • Don’t correct hypocalcemia
          • Control hyperkalemia
          • HD if necessary
      • Wound infections
        • Adipocyte hypertrophy changes adipose structure and impaires function
        • Inflammatory mediators invade: chronic low grade inflammatory environment with angiogenic inhibitors and fibrosis, tissue becomes hypoxic
        • Impaired collagen synthesis
  • Late complication
    • Anastomotic strictures: within 6 weeks 10% incidence
      • Lower with linear staples
      • Controlled with balloon dilation
      • Marginal ulcers ~6%
      • Epigastric pain, can bleed/perforate
      • Most tx with PPI: may need lifelong
      • If unresolved: r/o gg fistula
    • Nutritional:
      • MC: B12, folate, vit d, calcium, iron, B1, B6, vit A, zinc, selenium, mg, Cu
      • wernicke’s polyneuropathy (acute thiamine deficiency and glucose immediately), malnutrition
    • Cholelithiasis
      • MC during rapid wt loss >1.5kg or % BW /wk
      • Cholesterol supersaturation of bile
      • Increased nucleation
      • Decreased calori intake lowers CCK secretion
      • Obesity related cck resistance
      • Concurrent routine chole controversial: 36% will get stones post RYGB
      • Urso 300mg bid x 6 mo: prevents GS formation
    • Weight regain
      • 2’ pouch dilation or GG fistula
      • MC 2’ to non complicance and poor food choices/portioning
    • SBO: 0.5% incidence
      • Etiology: internal hernias, adhesions, trocar hernias, JJ intussusception, hemobezoar
      • Internal hernias can occur at the jejunojejunostomy defect, Peterson’s space behind the roux limb, or transverse mesocolon defect if retrocolic limb
      • Sx: vague, pain out of proportion. Likely will not have vomiting
      • Gastric remnant blow out is fatal: rapid dx and tx vital
      • CT: can miss/be misread >60% of cases
      • Low threshold for exploration
  •  NB
    • Unemancipated minors can’t consent (technically), need to assent with parental consent
    • Medical tx
      • Orlistat: antiobesity medication: inhibits gastrointestinal lipases and leads to dec fat absorption
      • Sibutramine: oral agent inhibits neurotransmitter reuptake
      • a/e cardiac morbidity

Laparoscopy

  • Benefits: reduced trauma and stress response
    • Closed abdomen may be a factor
  • Physiologic benefits
    • Less impairment of pulm fxn
    • Less blood loss
    • Less immune suppression
    • Less stress response
    • Less adhesions
  • Clinical benefits
    • Less pain: less narcotic use
    • Quicker resumption of diet
    • Shorter LOS
    • Quicker return to work
    • Less incisional hernia
    • better return of normal lung volumes (FVC and FEV1)
  • Entry Techniques: no advantage in preventing major complications
    • Types: Veress Needle, Hasson: Open direct, Optical Viewing Trocars
  • Physiology: Insufflation
    • Insufflation: CO2 gas: 12-15mmHg
      • Gas exchange: CO2 + H20 = H2CO3 = H + HCO3: resp acidosis
      • Asa 1/2: no effect
      • Asa 3/4: increased map and increased svr with decreased CO leads to hypoxia and dec o2 delivery
    • Altered ventilation
      • Increased IAP: like a severe valsalva
      • Decreased FRC: increased alveolar dead space
      • Increased airway pressure
      • Decreased compliance 2′ decreased diaphragm excursion
      • CO2 rapidly absorbed from the peritoneal cavity
        • Causes hypercapnea and respiratory acidosis
      • Requires an inc in minute/tidal volume to keep pco2 acceptable: up to 16% to maintain normocarbia
        • Anesthesiology increases rate to compensate
    • Altered hemodynamics
      • Increase in catecholamines, angiotensin and vasopressin
      • Venous return (ivc) is decreased
        • Decreases stroke volume and thus decreases cardiac index
      • Response is increased SVR: lasts up to 30 min post procedure
        • SVR = ((MAP-VCP)*80) /CO
      • Increased intrathoracic pressure
      • Increased CVP and PCWP
      • Increased PVR
      • Decreased CI: Caused by decreased SV 2’ to IAP compression of IVC causing decreased venous return
        • CI = HR * SV / BSA
      • Reduced CO: bad for: cardiomyopathy, as, etc
      • Response dependent on volume status of pt
        • Typically pt are low or euvolemic
      • Pt Positioning
        • Trendelenburg: enhances altered hemodynamics
        • Reverse trendelenburg: worsens these effects
    • Immune system response
      • White cells still rise
      • Acute phase reactants: CRP
        • Rises 4-12 hours after surgery, peaks 1-3 days, remains elevated for 2 weeks
        • Less rise with laparoscopy: likely secondary to CO2gas (not just incision size)
      • CD3 down reg
      • Activated lymphocytes down reg
      • Cytokines: Less rise of IL 6, TNFalpha, IL1, granulocytes
    • Neuroendocrine response
      • Less elevation of adrenal hormones: cortisol and epinephrine
      • Less elevation of sympathetic hormones: dopa and norepi
      • Less elevation of pituitary hormones: acth, prolactin, growth hormone
      • All have 20-40% lower peaks
      • Faster return to normal 4 v 9 hours
      • Peak glucose increase 25% less
    • Increased intra-abd pressure stretches diaphragm and irritates nerves
      • No increased risk of DVT
    • Altered Renal Blood flow
      • Decreased RBF during tension pneumoperitoneum
      • Increased renal vein pressure
      • Decreased urine output: usually not clinically relevant
      • Increased renal blood flow after exsufflation: usually no effect on serum creatinine
      • Preserve function with pressure <20mmHg
      • Tx: Increase in fluid administration, dopamine
    • Increased ICP
      • Independent of arterial pH, oxygenation and MAP
      • Mechanism not elucidated
      • Usually without clinical consequence
  • Complications
    • Bradyarrythmia on induction of pneumo:
      • 2’ to vagal stimulation induced by peritoneal stretching on insufflation
      • Tx/ immediate cessation of surgical stimulation
        • Deflate abdomen
        • Glycopyrrolate or atropine
    • CO2 embolism
      • CO2 directly into venous channel: obstruction of R ventricular outflow tract
        • Decreased end tidal co2
      • MC during hepatectomy
      • Cyanosis
      • Increased venous pressure
      • Ventricular arrhythmia
      • Tx
        • Stop insufflation
        • Left Lateral Decubitus: head down
        • Hyperventilate
        • Aspirate gas from R atrium through central venous catheter
    • SubQ emphysema during or after laparoscopy
      • Presents as crepitus
      • Frequent occurrence: leak around abd insufflating port
      • Can be assoc with respiratory acidosis
      • Prolonged postop ventilation
      • Will dissolve in 24-72 hours
      • May bruise
    • Shoulder pain: nerve irritaiton
      • Last up to 3 days
    • Aspiration of gastric contents:
      • increased IAP can increase risk of regurg
      • P/w tachycardia immediately following extubation (tx IS and nebs)
    • Injury to viscera: bladder, bowel
      • Bladder
        • Repair primarily
        • Leave foley 7-10 days
      • Enterotomy 1.8%
        • Immediate:
          • Cx/ Trocar, suture passer, adhesiolysis
          • Primary repair
        • Delayed: 20% missed, 8% mortality
          • Cx/ Thermal burn: cautery ultrasonic shears
      • Bleeding
        • From trocar site: figure of 8 suture or hook cautery: don’t ignore
        • From trocar entry:
          • Convert to open, isolate injury primary repair
  • NB for common procedures
    • Chole: Identify the critical window
    • Colon: Right, Left and LAR
      • Risk: bleeding, infection, visceral/ureteral injury, leaks
      • Minimize risk: medial to lateral dissection, proper visualization, proper identification of anatomy
      • Benefit: less pain, fewer wound complications
    • Hernia
      • TEP: total extraperitoneal rpr
      • TAPP: transabdominal pre peritoneal rpr
      • Risk: chronic pain, recurrence
      • Chronic pain: TEP less than open
      • Lap: more expensive, but can catch b/l hernias
      • Higher recurrence (veterans data)
      • Recurrence do opposite of first: lap/open
      • Recurrence after lap inguinal: inadequate dissection, mesh fixation and pt obesity and smoking
  • Future
    • SILS
      • Growth preceeds clinical benefit
      • Increased hernia’s
      • Body image better, Cost higher
    • NOTES: experimental
    • Robotics: level 5 (expert opinion) evidence:
      • better cosmesis
      • Less pain, shorter LOS, less ebl
      • More expensive, longer OR times