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FLS Written
Laparoscope diameters - answer2-10 mm Laparoscope lengths - answer30-45 cm Hopkins Rod lens system - answer light from source to operative field >> capture and transmit reflected light through the scope and camera couple >> light sensitive chip in the camera head Decreasing ability for image capture with what factors? - answer increasing length, increasing angle, and decreasing diameter (ex: 5 mm, 30 degree scope admits less light than a 10 mm, 0 degree scope) Laparoscopic damage susceptibility increases with which factors? - answer decreasing diameter, increasing length 0 degree laparoscope most useful? - answer when structures most in line with the trocars and in small places (deep pelvis, high mediastinum) 30- and 45-degree laparoscope - answer offer more flexibility/versatility than 0 degree (but need more skills) Troubleshooting smudge on laparoscope? - answero Wipe on clean tissue (liver or bowel) o Remove scope and clean with towel o Clean port (newer systems may not need this as no mechanical seal) Warmed/humidified CO2 - answerdecreases postop pain and temperature (compared to gas directly from cylinder) but is not clinically significant in cases < 90min High powered light source wattage? - answer300 watt Xenon lamp "Picture in Picture" feature - answer· Helpful if need for intra-op of flexible endoscopy or ultrasound of GI or GU tract, liver ultrasound, hysteroscopy, bile duct exploration o Basically smaller picture in corner to show scope imaging + additional images · Work space decrease in size: Actual pressure higher than set pressure = - answero Patient may not be sufficiently relaxed or there is obstruction o Twitch monitors may not represent this well as diaphragm recovery from paralytics differs from skeletal muscles o Mechanical obstruction - closed valve on port, kink, standing on tubing
Low pressure and high flow rate = - answer= leak in system o tubing disconnected from insufflator or port o Valve open—check to make sure valves are cloed o Check all port sites for leaking CO o Hollow organs check distension of bowel or bladder catheter Waveforms - answercoag, cut, blend · Tissue effects: - answero Vaporization: 'cut', non-contact, deep injury with minimal lateral damage o Fulguration: 'coag', non-contact, superficial wide injury o Desiccation: either, contact with instrument, deep/penetrating injury --However, 'cut' gives you most thorough desiccation! Harmonic scalpel - answer· uses mechanical energy, so no dispersive electrode needed o Little lateral injury, good for small vessels · Ligasure - answero Bipolar, continuous waveform, measures tissue impedance and shuts down as needed o single application is sufficient! If jewelry cannot be removed, then? - answer· use gauze and tape to increase contact area and to minimize current concentration · jewelry should not between dispersive electrode and surgical site Current Density = - answerCurrent (amps)/Area (cm2) Current Density proportional to - answerpower (the current) Current Density inversely proportional to - answero tissue resistance and area squared o Smaller the contact area, greater the current density >> faster heating o Tip of electrode is small, so contacting a small area of tissue generates high current density dispersive pad (grounding pad) location - answero minimal heating and maintains low density -- don't place on hair, bony prominence, or scars which may cause decrease in contact surface area and increase risk of burns -close to surgical field, near vascular muscle mass (due to increased water content), transverse Monopolar cutting: - answer· Circuit (Electrical surgical unit) ESU converts low frequency current from wall unit to high frequency current (active electrode - metallic portion of instrument) and dispersive electrode connected to generator
Bipolar - answer· Tissue between two electrodes, no need for dispersive electrode, smaller area (less resistance), less lateral tissue dispersal compared to monopolar o May seal vessels up to 7mm >> denaturation of collagen on vessel wall, creating permanent seal o Some have cutting device incorporated to divide the vessel after o Hazards § Thermal injury § Cutting patent vessels before sealing § Improper device function if metal within jaws Piezoelectric transducer - answero Converts electrical energy to ultrasonic vibration = tissue heating o Torque is needed o Vibration seals and divides tissue o Shears: Vibrating jaw and Passive jaw (acts as backstop to trap tissue against active blade) - minimal heat is transferred; active blade is unprotected! Piezoelectric transducer power - answero 50k times per sec or Hertz o Lower power settings lead to better hemostasis; higher power settings lead to better cutting Which ASA classes cannot tolerate pneumoperitoneum? - answerASA 4- ASA 4: A patient with a severe systemic disease that is a constant threat to life. Example: Patient with functional limitation from severe, life-threatening disease (e.g., unstable angina, poorly controlled COPD, symptomatic CHF, recent (less than three months ago) myocardial infarction or stroke. ASA 5: A moribund patient who is not expected to survive without the operation. The patient is not expected to survive beyond the next 24 hours without surgery—examples: ruptured abdominal aortic aneurysm, massive trauma, and extensive intracranial hemorrhage with mass effect. Anticoagulants should be stopped - answer3 days prior to surgery Trocar placement in obese patients - answero Can use spinal needle first to assist in obese patients to determine length of trocar needed o Long trocars > 100 mm o May need Veress Trocar placement in thin patients - answero Aortoiliac vessels may be in close proximity to anterior abdominal wall thus elevate abdominal wall or place Veress away from midline (along coastal margin) or go in with an optical trocar Absolute contraindications to laparoscopic surgery - answerInability to tolerate laparotomy
hypovolemic shock lack of proper surgeon training lack of institutional/facility support Relative contraindications to laparoscopic surgery - answerInability to tolerate GETA longstanding peritonitis (as likely will have dense adhesions = increased risk of injury and limit operative exposure) large pelvic mass due to decreased visualization incarcerated ventral and inguinal hernias (challenging to reduce hernia and can lead to decreased peritoneal space) severe cardiac or pulm disease intolerance to positioning previous abdominal surgery** Cirrhosis increases risk of - answer· bleeding and ascites leakage from the incisions in small bowel obstruction how to handle bowel? - answer· follow/handle areas distal to transition point to avoid handling distended bowel Contraindications to LSC cholecystectomy - answerGallbladder cancer, portal hypertension, cirrhosis, acute cholecystitis, Mirizzi syndrome (common hepatic duct obstruction from EXTRINSIC compression from impacted stone in cystic duct or infundibulum of gallbladder) Contraindications to LSC Appendectomy - answerLarge abscess, phlegmon Contraindications to LSC Emergency laparoscopy - answerLongstanding peritonitis, hemodynamic instability partially corrected with resuscitation, massive bowel dilation Contraindications to LSC Colon resection - answerLarge fixed mass, dense pelvic adhesions, massive bowel dilation, T4 tumors Contraindications to LSC Pelvic laparoscopy - answerlarge fixed mass, inability to tolerate Trendelenburg Contraindications to LSC Foregut procedures - answerPrevious gastric operation (at GE junction), hepatosplenomegaly Contraindications to laparoscopic anti-reflux surgery - answerEsophageal shortening, epithelial dysplasia, previous gastric surgery (esp at GE junction), liver enlargement, large hiatal hernia Contraindications to LSC Hernia repair - answerlarge chronically incarcerated hernia, acutely incarcerated hernia requiring bowel resection, need for removal of large prosthetics, need for skin graft removal or large scar revision
Veress needle - answerSpring loaded needle - outer sheath has sharp tip and is shorter than the inner blunt tip, inner needle is the conduit for insufflation gas --Gastric decompression can decrease risk of injury Intraperitoneal check for Veress - answerMost accurate is connecting the insufflation on low or medium setting and noting a low starting pressure Complications of Veress needle - answerBowel injury, mesenteric or omental vascular injury, cardiac arrhythmia, hypotension, high airway pressures, pneumothorax, gas embolism Must avoid what vessels with secondary trocars? - answerSuperficial and deep epigastric vessels CO2 properties - answerrapidly absorbed, easily eliminated, suppresses combustion, soluble in blood (diffusion coefficient is 20 times higher than oxygen), readily available, and inexpensive CO2 insufflation chemical changes --> - answerrapid rise in end tital CO2 concentration and arterial CO2 >> drop serum pH o Vigilant monitoring of patients with cardiopulmonary disease (end tidal CO2 needs to be watched, esp in first 20 min) o To breath off CO2 - increase minute ventilation CO2 insufflation --> respiratory changes --> - answerIncreased intraabdominal pressure reduces functional residual capacity increases peak airway pressure decreases pulmonary compliance CV changes due to insufflation - answercaused by: pressure of pneumoperitoneum, patient position, acid base disturbance from CO o Increased pre and after load --> decreased cardiac output o Decreased Cardiac output --> Cardiac index is decreased o Arrhythymias: sinus tachycardia (most common; usually mild and self-limited), PVCs (rarely problematic), bradycardia (due to vagal response, soon after pneumoperitoneum achieved) Insufflation effect on vena cava - answer§ 26-39% decrease venous flow rate § 0.5% chance of VTE
§ Patient specific: Age>40, history of DVT, immobility, varicose veins, cancer, chronic renal failure, obesity, peripartum, CHF, myocardial infarction, HRT, OCPs, multiparity, IBD, severe infection Insufflation effect on renal system - answero Increased intraabdominal pressure reduces renal perfusion à decreased filtration and UOP o Release in renin and ADH --> free water and salt reabsorption = oliguria o Intraoperative oliguria is common, usually resolves within a few hours postop Hypothermia risk with insufflation - answer· high risk with longer cases (>90min), use warm or humidified CO2 gas o Warm IV fluids o Forced air body surface warmer o Warm room temperature o Warm irrigation fluid Gas embolism risk with insufflation - answero Small, asymptomatic emboli occur frequently o Symptomatic are rare <0.015% and manifest as sudden cardiovascular collapse o Diagnosis: severe hypotension, jugular venous distension, tachycardia, mill wheel murmur --> rule out other sources of hypotension o Place patient in Trendelenburg, left side down (to prevent entrance of embolism to right ventricular outflow tract), rapid fluid administration, central line to evacuate or break up embolus in right heart Alternative insufflation agent: Nitrous oxide - answer§ Benefits: less acid-base disturbance, increased tolerance without general anesthesia, better tolerated in patients with severe CP disease, and slightly less postoperative pain § Risk: Fire hazard if using electrocautery in the presence of open bowel - supports combustion (it is not flammable with cautery alone, only flammable around combustable gases - like methane within the bowel) Alternative insufflation agent: air - answer-- Alternative insufflation agent: Helium + Argon - answerNo acidosis or hypercarbia decreased solubility thus increases risk of gas embolism due to peritoneal extravasation more expensive and less readily available 5mm or smaller do not require closure of fascia except in - answerpediatric patients o Most common sites of unrecognized bleeding - answer§ Trocar injury of abdominal wall vessels § Injury to vessels or organs away from operative field (e.g. liver and spleen)
Types of suture: Braided - answereasier to tie, don't need as many knots, lack elastic memory Preferred needle type - answer· tapered noncutting is preferred for LSC (also safer) Grab needle where? - answero Grab needle 5 mm away from junction point Intracorporeal knot tying: Ideal length - answer6 in/15cm Extracorporeal knot tying: Ideal length + hazard - answer30 in/76 cm Puts more strain on tissue than intracorporeal Roeder's knot - answero tied completely outside and then pushed inside to secure tissue (flat square knot first, longer free strand is then wrapped three times) o Good if suturing is required to approximate tissue also known as endoloop used for end of blood vessel, appendix, fallopian tube, cut end of cystic duct LSC Staplers can come through? Stapler length? - answerNeed 12mm port to introduce, 30-60 mm length Staple height by tissue: - answer· Vascular/mesentery/thin tissue: 2-2.5 mm (White/Grey) · GI tract: 3-3.5 mm (Blue) · Stomach or thick GI tract (if edematous): 4-4.5 mm (Green) Internal port site bleeding may not always be identified, so.... - answer§ Remove ports under direct visualization (Trocars placed through rectus muscles are at highest risk of injuring the epigastric vessels) Risk factors for PONV - answero Females o Younger age o H/o problems with PONV o H/o motion sickness o Non-smokers o Use of volatile anesthetics o Opioid administration o longer case o Prophylactic antiemetics: Serotonin 5-HT3 receptor antagonists - answer· Ondansetron · Tropisetron · Dolasetro
· Granisetron o Prophylactic antiemetics: Antihistamine H1 antagonists - answer· Promethazine · Cyclizine o Prophylactic antiemetics: others - answer· Metoclopramide · Dexamethasone · Droperidol Rescue antiemetic therapy - answerInitiate antiemetic treatment ASAP if no prophylaxis, switch classes if first drug didn't work Shoulder pain - answerDue to both chemical and pressure effects of pneumoperitoneum leading to diaphragmatic irritation. Self-limited and lasts 1-3 days · Diet is procedural dependent: days until full diet tolerated? - answero Appendectomy: 0- o Cholecystectomy: 0- o Fundoplication (for GERD, fundus of stomach is folded and sewn around the lower esophageal sphincter): 1- o Colon resection: 3- o GE junction: soft foods x few weeks due to temporary dysphagia o Bariatrics: liquid/soft foods x 2 weeks Frequent wound complications - answerseroma, infection, hematoma, hernia high flow insufflation - answer10 or more L per minute Sterile line: insufflator to patient --> Locked by: - answerluer-lock or push tube Camera and light source in closed housing have - answera decreased risk of fire Light travels through light cable with - answerfiberoptic cables Tissue heating = - answer= (Current Density) Density = - answer· Current flowing thru cross-sectional area of tissue o Proportional to power o Inversely proportionally to tissue resistance, and square of area In a appendiceal stump, ligature at highest danger of thermal burn if monopolar electrode is applied because - answerDiameter at ligature is half of stump so current density 16x greater
