FLS Didactics Notes Flashcards
Scope diameters
2-10mm
Scope lengths
30-45cm
Options for gas
CO2, nitrous oxide, helium
Video tower consists of
Light source, camera control unit, video monitor, insufflator
What light source is used to illuminate the body?
300 watt xenon lamp
The current density is defined as:
the amount of current flowing through a cross sectional area of tissue
Current density is directly & inversely proportional to:
Directly proportional to applied power; inversely proportional to 1) tissue resistance AND 2) the square of the area of tissue through which the current must travel.
Current density formula
Current density = current (amps) / area (cm^2)
Don’t place dispersive electrode (grounding pad) on:
Hairy skin, scars, bony prominences (decrease contact surface & increase risk of burn)
Cutting mode
- heats tissue quickly –> cell water converted to steam (explodes)
- heat dissipation = minimal lateral spread, poor thermal coag
- CONTINUOUS waveform, LOW voltage, little tissue resistance (steam bubble)
Fulguration definition
Rapid surface heating with superficial eschar formation and shallow depth of necrosis
Coag mode
- rapid surface heating with superficial eschar formation & shallow depth of necrosis (fulguration)
- INTERMITTENT (pulsed) waveform, HIGH voltage
- heat widely dispersed so no significant cutting
What is current diversion?
When current, following the path of least resistance, passes through unintentional pathways.
Capacitative coupling
Involves transfer of current from an active electrode, through its insulation, to a passive electrode (must be two conductors separated by an insulator)
Direct coupling
“spark”
Unintended direct coupling: when the active electrode comes into contact with other metal instruments, cannulas, or the laparoscope
Vessel diameter for bipolar tissue sealing devices
Up to 7mm
Examples of bipolar devices
Kleppinger, Ligasure (tissue placed directly b/w two electrodes)
Hazards of tissue sealing devices
1) inadvertent thermal injury
2) inadvertent cutting of patent vessels before sealing
3) improper function if metal is w/in the jaws (staples or clips)
Ultrasonic dissection relies on what type of energy?
Mechanical
The tissue heating with ultrasonic devices is generated by:
Converting electrical energy into high frequency, ultrasonic vibration, utilizing a piezoelectric transducer. Vibration seals and divides tissue.
Ultrasonic high vs low power (cut vs coag)
LOWER power settings result in relatively more HEMOSTASIS and HIGHER power settings result in relatively more CUTTING.
What are blades/jaws on piezoelectric transducer?
Active: vibrating; can injure tissue if touched immediately after use
Passive: backstop to trap tissue against the active blade; minimal heat transferred
Avoiding inadvertent tissue:
1) be aware of contact points the blade is engaging
2) grab & elevate target tissue
3) keep active blade upwards, in view of surgeon
What happens to current density if you half the diameter of a ligature/surgical site?
Increases 16 fold
Cutting mode:
During electrosurgery, the method of heating tissue quickly, converting cell water to steam & causing the cell to explode. (low voltage)
Capacitative coupling is a result of using what?
Using a metal trocar with a plastic screw anchor. Prevents the trocar from draining its charge.
Where should monitor be positioned?
At or just below eye level
Where should surgeon stand?
Opposite of the operative field for best ergonomic position. Wrists slightly pronated, thumbs up.
Ideal ergonomic position for surgeon?
Arms at a 30 degree angle from the trunk & elbows flexed 60-120 degrees & the wrists slightly pronated, thumbs up & straight, both radial-ulnar axis and flexion-extension axis are no more than 2-3 degrees of either access.
When should anticoagulation be discontinued?
Most should be discontinued at least 3 days prior to elective surgery.
NSAIDs pre/peri-operative:
There is no proof that non-steroidal anti-inflammatory medication, including aspirin, need to be discontinued prior to safely proceeding with laparoscopic surgery
Pulmonary or cardiac medications recs in the perioperative period?
Any pulmonary or cardiac medications are important to continue throughout the perioperative period.
Which ASA Classes are contraindicated in LSC surgery?
ASA 4 and ASA 5; may not be appropriate candidates b/c their marginal cardiopulm. reserve is often unable to tolerate the physiological changes caused by pneumoperitoneum
ASA Class 1
Normal healthy person; no organic, physiologic, biochemical, or psych disturbance
ASA Class 2
Mild systemic disease (due to either surgical condition or to concomitant disease); normal pregnancy, smoker, social ETOH drinker, obesity (BMI 30-40), well controlled HTN/DM, mild lung dz
ASA Class 2 OB examples
normal pregnancy, well controlled GHTN, PreE without, diet controlled GDM
ASA Class 3
Severe systemic dz that causes functional limitations; morbid obesity BMI 40 and up, HTN, COPD, ETOH abuse, ESRD, h/o MI/CVA
ASA Class 3 Pregnancy examples
PreE with SF, GDM with complications or high insulin requirements, thrombolic dz requiring anticoag
ASA Class 4
Severe systemic dz that is life threatening; recent (<3 mo) MI/CVA/TIA/CAD/stents, ongoing cardiac ischemia, severe valve dysfunction, sepsis, shock, DIC, ESRD not on dialysis; HELLP
ASA Class 4 Pregnancy examples
PreE with SF complicated by HELLP, peripartum cardiomyopathy with EF <40, decompensated heart dz
ASA Class 5
Moribund pt who’s not expected to live w/o the surgery; uterine rupture
ASA Class 5 Pregnancy example
Uterine rupture
ASA Class 6
Brain dead pt whose organs are being removed for donation
Obese pts
- Longer trocars placed PERPENDICULAR to abd wall
- Length: >100mm (>10cm)
Thin patient trocar placement
- elevated abd wall, insert at 45 degrees towards pelvic
- place veress away from midline & around costal margin
- Open/hasson or optical trocar (rec’d if prior abd sx)
Absolute contraindications to LSC (4)
1) inability to tolerate OPEN
2) hypovolemic shock (if unable to resuscitate)
3) lack of surgeon training
4) lack of appropriate institutional support
Relative contraindications to LSC (5)
1) Inability to tolerate general
2) Long standing peritonitis
3) large abdominal or pelvic mass
4) Massive incarcerated ventral and inguinal hernias
5) severe cardiopulm dz (can’t tolerate positioning)
Considerations w/ prior abd surgery
- increased adhesions
- increased risk of enterotomy
- veress insertion shouldn’t be close to previous incisions
Cirrhosis considerations
- increased risk of bleeding and postop ascites leak from LSC wounds
- medically manage ascites before sx
During which trimester is LSC safe in pregnancy?
ALL
Special precautions for pregnancy and LSC surgery:
1) Tailor initial access based on fundal height
2) lower insufflation pressures
3) FHTs pre and post op
4) lateral recumbent position
Anesthetic options for local anesthesia (3)
- Bupivocaine
- Lidocaine
- Ropivacaine
Arm positioning
- pelvic/lower abd: tuck 1 or both arms, hands not flexed
- upper abdomen: arms on the side, ABducted at 90 degree (not >90 to avoid brachial plexus injury)
Allen stirrups vs candy cane?
Allen is better to avoid less extreme angulation
Lateral decubitus position
-avoid stretch on brachial plexus
-**Roll on dependent side can -protect axilla & plexus
upper arm in a sling
- bean bag can hold pt a the right angle but can cause pressure injuries b/c its stiff (use padding on the bean bag)
Modified decubitus
Used to allow rotation b/c full lateral decub. and supine
Entry site for establishing pneumoperitoneum:
Umbilicus is most common
Alternative entry site for establishing pneumoperitoneum if:
- previous umbilical scar, h/o umbilical hernia repair, if site not optimal location for surgery
Most accurate intraperitoneal check
Low insufflation pressure (<8mmhg) w/ low to medium flow of CO2
Absolute contraindication to blind trocar insertion:
1) abdominal scar from prior OPEN surgery in immediate vicinity of trochar insertion
2) Through previously placed intraperitoneal mesh for hernia repair
Palmer’s point
LUQ midclavicular at anterior axillary line 3cm or two finger breadths below ribs
- *go lateral to epigastric vessels when using site off midline
- avoid rectus muscles
Most common vessel injured with veress insertion
The take off of the right common iliac artery from aorta lies directly below umbilicus; it’s most commonly injured in thin patients (retroperitoneal injury)
Hasson (open) technique:
- Make a 2 cm vertical or horizontal skin incision
- Carry incision down through the skin & subQ
- incise fascia with scalpel or monopolar cautery on CUT
- anchor fascia w/ 0 or 2-0 absorbable suture (simple or horizontal matress) (placed before OR after entering peritoneum)
- dissect preperitoneal fat
- grasp peritoneum w/ 2 clamps & incise sharply
- insert blunt tipped trocar under direct visualization
- secure trocar to the fascia with the previously placed stay sutures
- connect insufflator tubing & initiate pneumoperitoneum
What gas preferred and why?
CO2
Available, inexpensive, rapidly absorbed and SOLUBLE in blood, easily eliminated by alveoli in lungs, suppresses combustion
CO2 effects
INC arterial CO2»_space; INC end tidal CO2»_space; DECR serum pH
CO2 pulmonary effects
- INC minute ventilation to eliminate absorbed CO2
- INC pressure pushing diaphragm cephalad»_space; DECR func residual capacity, INCR peak airway press, DECR pulm compliance & diaphragmatic excursion
Cardiac output response
Usually DECREASES due to both chemical and pressure effects
Cardiac output response (preload, afterload, CO)
INCREASED preload, INCREASED afterload, DECREASED cardiac output
CO decrease exacerbated by:
Reverse T-burg, hypovolemia, underlying cardiac dz, pneumo/vagally induced bradycardia»_space; decreased tissue perfusion manifests as HYPOTENSION, arrhythmia, decr UOP, & INC end tidal CO2
decreased tissue perfusion manifests as:
HYPOTENSION, arrhythmia, decr UOP, & INC end tidal CO2
Intraop actions if symptomatic decreased cardiac output:
- desufflate immediately
- check insufflator settings/function
- check for adequate relaxation
- check intravascular volume status
- check for other causes such as bleeding
Most common cardiac change
Sinus tachycardia (mild and self limited)
PVCs are due to what affect of CO2?
Chemical (PVCs rarely problematic)
Bradycardia due to what?
- Vagally mediated & occurs soon after pneumo is established due to PRESSURE effect
- if severe, stop insuf. & release pneumo. Once stable, can re-establish pneumo w/ lower flow & pressure.
Persistent arrhythmia
Open or abort procedure
Increased IVC resistance due to what?
PRESSURE effect of pneumo
reduced LE venous flow rate
Alternative gases
Nitrous oxide, air, helium, argon
Nitrous oxide benefits
- less acid base disturbances
- better for pts w/ severe cardiopulm dz
- slightly less postop pain
- tolerated well w/o gen anesth.
Nitrous oxide risks
- does NOT suppress combustion
- **Fire hazard if using electrocautery in the presence of open bowel (from combustible gas in the bowel)
- do not use in pts w/o bowel prep or if high risk of bowel perf
Renal effects
- UOP unreliable due to PRESSURE effect
- INCR intra-abd pressure DECREASES renal blood flow & UOP»_space; RENIN/ADH INCREASES
- intraop oliguria is common
Gas embolus
- Small asymptomatic emboli occur frequently
- symptomatic = rare (0.015%)
Symptoms of gas embolus
- sudden cardiovasc collapse
- severe hypotension, JVD, tachycardia, MILL WHEEL murmur
Treatment of gas embolus
- stop insufflation & evacuate pneumo
- Place in Tburg, LEFT lateral decubitus w/ head down to prevent embolus from going to R outflow tract “Durants position”
- Rapid crystalloid fluid administration, 100% O2, TEE to dx if needed
- Central line placement to evacuate or break up embolus in R heart chamber
Core needle biopsy
- Tissue for histology eval (form of incisional bx)
- 14-18 gauge needle
- used for bx of liver
Incisional bx used for
Larger lesions
Excisional bx used for
Smaller lesions
FNA biopsy
Cytology specimen, higher yield than washings
20-22 gauge needle
Electrocautery and bx
Avoid when obtaining specimen. Use only after to help w/ hemostasis (it can alter or distort specimen)
Bx of peritoneal lesions
- bx forceps, grasper, scissors
- small lesion > excisional
- large lesion > incisional
- remove via 5 or 10 mm port
LN bx
- usually EXCISIONAL bx is done
- Careful use of energy during bx
- smaller nodes removed via 10-12mm port, larger nodes using a sac
Bx of liver lesions below surface
FNA or core needle bx, may need US; hemostasis AFTER specimen is collected
Bx of fluid filled liver lesions
- cysts don’t need bx
- avoid vascular lesions b/c they can bleed
Bx of generalized liver parenchymal dz (cirrhosis)
Core needle bx, wedge bx of edge of liver
Bx of solid liver lesion
- small surface lesion: incisional or excisional; if flat, core needle or wedge
- large surface lesion: incisional bx (core needle or wedge)
- below surface: FNA or core needle
Bx of ovary if high suspicion of cancer
Oophorectomy (removal of cyst wall or wedge bx of solid lesion okay if not)
Options for bx of ovary (3)
1) oophorectomy
2) wedge resection (of solid lesion)
3) bx forceps (on antimesenteric portion)
Small superficial lesion on hollow viscous mgmt
Can be removed and serosal stitch placed over top
Retroperitoneal bx hemostasis
Avoid monopolar near major structures; use bipolar, endoloop, clips, etc.
use US if lesion not visible
MC bx under US
Core needle or FNA
Hemostasis after bx in general
PRESSURE first, monopolar, bipolar, topical agents, suture, ultrasonic
Braided suture (vs monofilament)
- easier to handle
- lack elastic memory
- less likely to fray
- requires less throws
Undyed suture
- can absorb blood and are hard to see
- dyed suture preferred
Which is preferred? Dyed or undyed suture?
Dyed
Which is preferred? tapered or conventional needle?
Tapered/smooth…they’re safer compared to conventional/cutting needle
How far apart should ports be w/ intracorporeal tying?
Greater than or equal to 10cm
Intracorporeal knot tying ideal suture length
15cm or 6in
Extracorporeal knot tying ideal suture length
76cm or 30in
Trocar size for SH needle
10-12mm
Port size for staples
12mm port
Clips used for
- small tubular structures
- **NOT for closing openings in hollow organs
Clip sizes
- 5 and 10 mm
- disposable applier: can place multiple clips w/o changing out instrument
- reusable: metal and plastic clips
Linear staplers…general mechanism
Places two or three rows of staples on either side of a knife plate that divides the tissue between the staple lines.
Staple length and height ranges
Length of staple cartridges range from 30mm to 60 mm. Staple size or height ranges from 2mm-4.5mm.
Smaller staples vs larger staples
- Smaller: more hemostasis, thinner tissue (vessels or mesentery)
- larger: thicker tissue
Staple color, height, examples
1) White/gray = 2-2.5mm = vascular application
2) blue = 3-3.5mm = majority of GI tract
3) green = 4-4.5mm = distal stomach, thick portions of GI tract
Choice of staple height depends on:
the thickness of the tissue
Good maneuvers to control bleeding
- *grasp & hold bleeding source
- *5mm atraumatic grasper to tamponade
- add extra trocars/maintain exposure
- 10 mm suction
- minimize irrigation
Highest risk of injury to epigastics
Trocars placed through rectus muscles
Port site bleeding: slow, visible source
energy source/electrocautery or direct pressure
Port site bleeding: high rate, no visible source
- control w/ grasper
- place foley catheter
- dissection to find source
- suture and/or energy source
Port site bleeding: heavy bleeding
- full thickness abdominal wall suture
Retroperitoneal bleed suspected when
Free blood seen in abd cavity with no identifiable source (presume a major vascular injury)»_space; convert to OPEN!!!
Management of LSC retroperitoneal bleed
CONVERT TO OPEN
Retroperitoneal hemorrhage due to veress needle injury
- MC vessel injured is iliac vein during trocar placement
- can have concomitant bowel injury, inspect bowel
- may have overlying viscera or be in mesentery of bowel
Retroperitoneal hemorrhage due to trocar injury
- more immediate blood loss, more easily dx’d
- attempt to tamponade bleeding while converting to open
Monopolar electrocautery for hemostasis used for:
small vessels, slow rate of bleeding, need relatively dry operative field
Bipolar electrocautery for hemostasis used for:
larger vessels, works in “wet” operative field, less lateral spread, lower energy requirement (advanced bipolar = improved hemostatic capability)
Hemostatic agents for bleeding control
- *useful for raw surfaces
- slow rate of bleeding
- not effective for large vessels
- some require special applicator
Prevention of shoulder pain
- *wound infiltration w/ local anesthetic
- lower insufflation pressure
- deliberate evacuation of pneumo after sx
- multimodal anesthesia
Tissue heating relationship to current density
**Tissue heating = (current density)^2
Cumulative radiation dosage during pregnancy
5-10 rads
Fetal mortality is greatest when radiation exposure occurs when?
w/in 1st week of conception
Most sensitive time period for CNS teratogenesis is:
b/w 10-17wga
avoid routine radiographs during this time (later in pregnancy, concern shifts towards increased risk of childhood hematologic malignancy)
No single diagnostic study should exceed _ rads.
FIVE
MRI recs in pregnancy
MRI without IV Gadolinium can be done at any stage of preg
- no adverse effects of amIR on fetal development have been reported
- Gadolinium crosses placenta & can be detrimental
CT scan in preg
- may be used judiciously
- rads can range from 2-5 (pelvis only vs abd/pelvis)
- safe rad dose but think about teratogenesis & childhood blood cancer
PET scan in pregnancy (radionucleotides)
safe
including technetium-99m
fetal exposure is <0.5rad
Cholangiography
may be used selectively
shield lower abdomen to decrease fetal exposure
Pregnant patient positioning
Left lateral decubitus
Minimize compression of vena cava
Pregnant initial port placement
- adjust based on fundal height and previous incisions
- open, veress, or optical trocar
Pregnant insufflation pressure
10-15mmHg
VTE ppx pregnant pt
Intra and post-op SCDs and early ambulation
