Bleeding Peptic Ulcer

What proportion of UGI Bleeds have a non-variceal cause?

80-90%

What are etiologic factors in the pathogenesis of peptic ulcers?

Aspirin, NSAIDS, and H. pylori

Smoking tobacco also inhibits the gastric mucosal barrier...
Remember that gastric ulcers may be secondary to underlying malignancy.

What are the types of gastric ulcers based on location?

Type I - lesser curvature / incisura
Type II - incisura + duodenum
Type III - prepyloric
Type IV - high on lesser curvature near GE junction
Type V - anywhere, secondary to NSAIDs

Types II/III are classically attributed to acid hypersecretion

What are common presenting symptoms associated with UGI Bleeding?

Hematemesis
Melena
Hematochezia with fast/severe bleeds
Orthostatic changes
Syncope
Tachycardia
Hypotension

What are initial steps of management of an UGI Bleed?

Large-bore peripheral access
Type and Cross-match blood
Obtain CBC, electrolytes, BUN, Creatinine, INR, PTT
Volume Resuscitation with crystaloid
Monitored Unit
Insert NGT - Lavage
Urgent Upper Endoscopy

What are you looking for with NG lavage?

Aspiration of bloody or coffee-ground material.
A negative lavage is indicated by aspiration of bilious material.

What is the Blatchford Score?

A risk-stratification tool that predicts the need for medical intervention in patients presenting with UGI bleed. The scale ranges from 0-23.
(1) SBP: 100-109 (1 point), 90-99 (2 points), less than 90 (3 points)
(2) BUN: 6.5-7.9 (2 points), 8.0-9.9 (3 points), 10.0-24.9 (4 points), less than 25 (6 points)
(3) Hgb - men : 12.0-12.9 (1 point), 10.0-11.9 (3 points), less than 10(6 points).
Hgb - women: 10.0-11.9 (1 point), less than 10 (6 points)
(4) Other variables: Tachycardia (1 point), Melena (1 point), Syncope (2 points), Hepatic disease (2 points), Cardiac failure (2 points)

What is the Rockall score?

A combination of clinical and endoscopic parameters that are used for risk-stratification of UGI bleed. The Scale ranges from 0-11 points.
CLINICAL :
-Age: Less tan sixty (0), 60-79y (1 point), over 80y (2 points)
-Shock: Tachycardia (1 point), SBP less than 100mmHg (2 points)
-Coexisting illness: Heart disease/CHF (2 points), Renal Failure, Hepatic Failure, or metastatic CA (3 points)
ENDOSCOPIC:
-Diagnosis: no lesion or Mallory Weiss tear (0), Peptic ulcer disease or esophagitis (1 point), UGI malignancy (2 points)
-Stigmata: Clean base, flat pigmented spot (0), UGI blood, active bleeding, visible vessel, or clot (2 points)

What is the Forrest Classification?

A classification of the likelihood of recurrent bleeding based on endoscopic appearance.
Grade IA - active spurting of blood
Grade IB - oozing of blood
Grade IIA - nonbleeding visible vessel
Grade IIB - adherent clot
Grade IIC - flat, pigmented spots
Grade III - clean-base ulcers

This is probably the only classification worth knowing... high risk lesions are Grades IA/B and IIA/B.

What is the management of high-risk lesions?

Endoscopic hemostasis
- injection therapy (vasoconstrictors, sclerosants, tissue adhesives)
- thermal therapy (heater probe, bipolar, argon plasma coagulation)
- mechanical therapy (endoscopic clips, loops, suturing/stapling devices)
Testing for H. pylori
Initiation of an IV proton pump inhibitor for 72 hrs, followed by an oral PPI
If hemodynamic stability is acheived, initiation of clear liquids 6 hrs after endoscopy.
Discontinuation of NSAIDS and antiplatelet agents.

There is no strong data to support the use of octreotide in the management of non-variceal GI bleeding.

What is the management of low-risk lesions?

Endoscopic hemostasis is not warranted
Start an oral PPI
Test for H. pylori
Initiate clear liquids after 6hrs
Discontinuation of NSAIDS and antiplatelet agents

What are predictors of re-bleeding?

History of peptic ulcer disease
Prior ulcer bleeding
Presence of shock at presentation
Active bleeding during endoscopy
Large ulcers (greater than 2cm)
Large underlying bleeding vessel (greater than 2mm diamenter)
Ulcers on the lesser curvature of stomach
Ulcers on the posterior or superior duodenal bulb

What are the benefits of using proton-pump inhibitors?

They significantly decrease the risk of ulcer rebleeding by 60%, the need for urgent surgery by 50%, and the risk of death by 57%.

What is a non-operative option for addressing an acute GI bleed that has not been identified or controlled by endoscopy?

Angiography with transcatheter embolization
- Gelfoam, polyvinyl alcohol, cyanoacrylates, coils
Success ranges from 52-94%, with recurrent bleeding requiring repeated embolization in 10% of patients.

In most institutions, this is reserved for endoscopic failures, especially in high-risk surgical candidates.

What is the operative management for a bleeding gastric ulcer?

-Distal gastric resection to include the ulcer (Antrectomy)
-For Type II/III ulcers (hypersecretors), consider adding a vagotomy to the antrectomy... otherwise, long-term acid suppression
-In high risk patients, gastrotomy with wedge resection of ulcer, or oversewing and biopsy of the ulcer may be considered

All patients should be tested for H. pylori
Gastric ulcers should always be biopsied if not excised to rule out cancer.

What is a Pauchet procedure?

An antrectomy with extension of the resection line to include the lesser curvature of the stomach in order to include an ulcer near the GE junction. A Billroth II gastrojejunostomy is commonly performed.

What is a Csendes procedure?

Resection of the gastric antrum and body up to the GE junction (subtotal gastrectomy). A Roux en Y gastrojejunostomy is performed along the resection line.

What is a Kelling-Madlener procedure?

An antrectomy, truncal vagotomy, and ulcer biopsies, while leaving a large GE junction/Type IV ulcer in place

What is a Mallory Weiss tear?

A linear mucosal tear at the GE junction.

Rarely do these require an operation...

What is a Dieulafoy's lesion?

An abnormal submucosal arteriole, usually in the proximal stomach, but can be anywhere in the GI tract.

What is the etiology of bleeding duodenal ulcers?

90% have H. pylori colonization of the antrum.
Massive bleeding is usually the result of transmural ulceration of the posterior duodenal wall, leading to erosion of the gastroduodenal artery.

What is the operative management of a bleeding duodenal ulcer?

Upper Midline Incision
Kocher maneuver to mobilize the duodenum medially
Longitudinal pyloromyotomy, extending 3cm on each side of the pylorus
Digital pressure of ulcer base to temporize bleeding
Allow resuscitation measures to catch up...
Suture ligation x2 of gastroduodenal artery proximal and distal to site of penetration
U-stitch (#3) is place medially in between to control the tranverse pancreatic branch...
Gastric antral biopsies for H. pylori
Truncal Vagotomy and Pyloroplasty

-some will forgo a V+P by controlling the ulcer through a longitudinal duodenotomy and medically treating the patient with PPIs and H. pylori eradication.
-An alternative operation that is the procedure of choice for a chronic bleeding duodenal ulcer is oversewing the ulcer then performing a V+A (truncal vagotomy and antrectomy).

The risk of ulcer recurrence after a V+A is 2%, compared to 5% after a V+P.

What is a Heineke-Mikulicz pyloroplasty?

Transverse closure of the longitudinal incision

What is a Finney pyloroplasty?

Side to side closure of elongated pyloroduodenotomy

What is a Jabouley pyloroplasty?

A gastroduodenostomy

Late... SG

References:
Gralnek IM, Barkun AN, Bardou M. Management of Acute Bleeding from a Peptic Ulcer. NEJM 2008; 359(9): 928-937.
Cameron's Current Surgical Therapy, 9th ed. (2008)

Pulmonary Embolism

Here's an essential for management of the postoperative patient...

Where does PE originate from?

Typically after propogation and embolism of thrombi that develop in deep veins... 79% of patients with PE have evidence of calf DVT.

What are pathophysiologic sequelae of PE?

1. Anatomic obstruction of pulmonary arteries... although pulmonary infarction is typically avoided since lungs are also supplied by bronchial arteries.
2. Platelets cause the release of serotonin and vasoactive substances resulting in elevated pulmonary vascular resistance and V/Q mismatch.
3. RV afterload increases, leading to RV dilatation, ischemia, and right sided heart failure.

What are chronic sequelae of DVT and PE?

Post-thrombotic syndrome (chronic leg pain/swelling)
Chronic thromboembolic pulmonary hypertension

What are classic risk factors for DVT?

Virchow's triad - stasis, injury, and hypercoagulability

Also advanced age, obesity, pregnancy + postpartum period, malignancy, reduced mobility, polycythemia vera, smoking, central venous catheters, HITS, antiphospholipid antibodies, lupus anticoagulant
Medications - chemotherapy, oral contraceptives (3X risk), hormone-replacement therapy (2x risk), tamoxifen
Acutely-ill, hospitalized, medical patients have a risk of 15%

What specific populations are at high risk for DVT?

Total hip and knee replacement (risk of >50% without prophylaxis)
Cancer surgery
Major trauma
Spinal cord injury

What are genetic disorders that predispose to risk of venous thromboembolism?

Protein C and S deficiency
Antithrombin deficiency
Factor V Leiden
Prothrombin mutation (g20210a)
Hyperhomocyteinemia (C677T mutation)
Dysfibrinogenemia
Plasminogen deficiency

What isthe most common genetic risk factor for thrombophilia?

Factor V Leiden. This causes resistance to activated protein C

What are signs and symptoms of lower extremity DVT?

Leg pain, tenderness, warmth, or swelling

Homan's sign - calf pain with passive dorsiflexion at the ankle

What are signs and symptoms of PE?

dyspnea (73%)
tachypnea (70%)
pleuritic chest pain (66%)
rales / crackles (51%)
cough (37%)
Tachycardia (30%)
Leg swelling (28%) or pain (26%)
Fourth hearth sound (24%)
Loud P2 (23%)
Hemoptysis (13%)
Palpitations (11%)
JVD, systolic murmur, right sided gallop
syncope
hypotension
hypoxemia
PEA/cardiac arrest

Cardiogenic shock is diagnosed in 5% of acute PE.
While hypoxia and an Aa gradient is common, a normal ABG is seen in up to 20% of PE.

What are ECG findings of PE?

Tachycardia
V1-V4 T wave inversion
S1-Q3-T3 pattern
Right bundle branch block
P-wave pulmonale
Right axis deviation

These are nonspecific and are more often seen with very large PE

What are abnormal findings on CXR attributed to PE?

Westermark's sign - focal peripheral oligemia caused by PE obstruction
Hampton's hump - peripheral wedge seen above diaphragm
Palla's sign - enlarged right descending PA

How does D-dimer testing help with a diagnosis of PE?

This is a sensitive (96-98%) but very non-specific test.
It must be considered together with clinical suspicion and is better for patients presenting to the emergency room than for general surgical postop patients.
If the DDimer is negative in patients with a low-to-moderate pretest probability, imaging is not useful since PE is very unlikely.
If the patient has a high pretest probability, don't bother with checking a DDimer and go straight to imaging.

What imaging strategies are used for diagnosis of PE?

Spiral CT-angiography (90% sensitivity, 95% specificity)
Ventilation/Perfusion Scanning - limitation: frequently non-diagnostic
Pulmonary arteriogram
Venous duplex for DVT
Echocardiography for hemodynamically significant PE

Use caution when Cr>1.5 with CTA
Avoid V-Q scanning if there is associated cardiopulmonary disease noted on CXR

What are treatment stategies for DVT?

Outpatient management with low-molecular weight heparin transitioning to warfarin with a goal INR of 2-3 for 3-6 months

Pregnant patients can't take warfarin and must be kept on a LMWH...

What are treatment strategies for PE?

PE should be managed by inpatient hospitalization.
Parenteral unfractionated heparin (therapeutic PTT), low-molecular weight heparin, or fondaparinux for at least 5 days while starting warfarin - bridging therapeutic INR of 2-3 for 2 consecutive days, continuing treatment for 3-6 months.

Factor VII - measured by the INR - has a half life of 6hrs... however thrombin (factor II) depletion takes 5 days...

How is unfractionated heparin administered?

It is bolused 60-80 U/kg, followed by a continuous infusion of 18 U/kg/hr. The infusion is titrated to a therapeutic PTT (60-80 seconds) by checking the PTT level every 6 hrs.

What are benefits of LMWH?

These have more predictible pharmacokinetics and greater bioavailability than unfractionated heparins, allowing subcutaneous administration once or twice per day.

Therapeutic dosing for enoxaparin is 1mg/kg SC BID or 1.5mg/kg SC QD

How can you monitor if levels of LMWH are therapeutic?

Check anti-factor Xa levels

This is not as convenient as a PTT, but consider this in morbidly obese or pregnant patients, or if there have been issues with renal function.

What is fondaparinux?

A synthetic pentasaccharide that inhibits Factor Xa
Structurally, it looks like the antithrombin-binding portion of heparin. It is administered once daily, subcutaneously.

This should not be used in patients with severe renal insufficiency.

What if the patient has heparin-induced thrombocytopenia with thombosis?

The patient should be treated with direct thrombin inhibitors (argatroban or lepirudin). Warfarin treatment should be held until the disease process is controlled and the platelet count has normalized to avoid thrombotic complitcations and warfarin-induced skin necrosis.

Lepirudin is excreted by the kidneys and argatroban is metabolized by liver.

What is the risk of death from recurrent thromboembolism in patients treated for DVT?

0.4%

What is the risk of death from recurrent thromboembolism in patients treated for PE?

1.5%

What are indications for a vena caval filter?

Contraindications to anticoagulation
Major bleeding complications during anticoagulation
Recurrent DVT or PE while receiving adequate therapy

Retrievable filters can often be inserted... although often times they are forgotten to be removed!
The tide is beginning to turn against prophylactically placing IVC filters, but they may be recommended in select trauma patients.

When is thrombolytic therapy considered for management of PE?

If the PE is severe enough to cause cardiogenic shock or right ventricular dysfunction

There is no hard data to answer this question... surgical embolectomy may also be considered in certain cases of massive PE when conservative measures fail.

What is the overall mortality rate for PE?

15% at 3 months

What is the optimal duration of therapy for a DVT or PE

If it is secondary to a reversible risk factor, including the postoperative state, 3-6 months should be sufficient.
If it is idiopathic or secondary to a documented hypercoagulable state, 6-12 months can be considered.
Patients with a DVT/PE secondary to cancer should be treated until their cancer has resolved, with a LMWH for whe first 3-6 months.
Patients with recurrent thromboembolisms may require indefinite therapy.

Late... SG

References:
Goldhaber SZ. Pulmonary Embolism. NEJM 339; 1998: 93-104.
Tapson VF. Acute Pulmonary Embolism. NEJM 358; 2008: 1037-1052.
Cameron's Current Surgical Therapy (9th ed.)

Acute Calculous Cholecystitis

A recent edition of NEJM has a nice review on this common surgical topic...

What proportion of patients with gallstones become symptomatic?

1-4% per year

What proportion of patients with symptomatic cholelithiasis develop cholecystitis?

20%

What is gangrenous cholecystitis?

When the gallbladder wall undergoes necrosis and gangrene.

What is emphysematous cholecystitis?

When gas is visible on imaging in the wall or lumen of the gallbladder... this is indicative of superinfection with gas-forming organisms and may lead to perforation without urgent intervention.

What is Mirizzi's Syndrome?

Obstruction of the common bile duct as a result of extrinsic compression of a stone within the gallbladder or cystic duct.

What is Murphy's Sign?

Arrest of inspiration while palpating the gallbladder during a deep breath.

What are ultrasonographic findings of acute calculous cholecystitis?

Gallstones
Gallbladder wall thickening, greater than 5mm
Pericholecystic fluid
Positive ultrasonographic Murphy's sign

It's also important to assess for choledocholithiasis by evaluating for a common bile duct dilated greater than 7mm or frank CBD stones.

The PPV of stones + Murphy's sign is 92%.
The PPV of stones + GBW thickening is 95%.
The NPV of no stones, and a normal GBW and no Murphy's sign is 95%.

What does a HIDA scan involve?

Hepatic scintigraphy uses an IV injection of technetium-labelled iminodiacetic acid analogues. These are excreted by the liver into bile, and allows visualization of the gallbladder within 30 minutes. An absence of filling of the gallbladder after 60 minutes indicates cystic duct obstruction and is 80-90% sensitive for cholecystitis.

Morphine can improve the specificity of the test by increasing resistance at the sphincter of Oddi. Overall, HIDA has greater specificity and accuracy in comparison to ultrasound, but is usually reserved when the diagnosis of cholecystitis is uncertain.

What is a 'rim sign' on HIDA?

A pericholecystic blush that is seen in 30% of patients with acute cholecystitis and 60% of patients with gangrenous cholecystitis.

What are the Tokyo guidelines?

Diagnostic criteria for Acute Cholecystitis:
Presence of one local sign/symptom, one systemic sign, and any confirmatory finding on an imaging test...
Local signs and symptoms: Murphy's sign, RUQ pain or tenderness, RUQ mass
Systemic signs: Fever, leukocytosis, elevated CRP

According to the Tokyo guidelines, acute cholecystitis can be subdivided into three grades of severity...

What are criteria for Grade 1 - Mild Cholecystitis?

No organ dysfunction
Does not meet criteria for a more severe grade

Early laparoscopic cholecystectomy is recommended.

What are criteria for Grade 2 - Moderate Cholecystitis?

The presence of any of the following:
WBC greater than 18,000
Palpable, tender RUQ mass
Duration greater than 72hrs
Marked local inflammation including pericholecystic abscess, hepatic abscess, gangrenous or emphysematous cholecystitis, or biliary peritonitis

Early or delayed laparoscopic cholecystectomy may be considered depending on the scenario and the surgeon's expertise.

What are criteria for Grade 3 - Severe Cholecystitis?

Organ system dysfunction - hypotension requiring pressors, mental status changes, respiratory insufficiency with PaO2/FiO2 less than 300, oliguria, Cr greater than 2.0, INR greater than 1.5, platelet count less than 100k

Management with antibiotics and percutaneous cholecystostomy tube may be considered, reserving surgery for treatment failures.

What is the optimal timing of cholecystectomy?

For most patients, early cholecystectomy may be favored. 15-20% who had their procedures delayed after the initial attack subsided require intervention before their planned lap chole.

In several studies/meta-analyses, there were no differences in operative time or conversion rates between early and delayed lap chole. However, bile duct injuries in general may be more common in the setting of acute cholecystitis. Postoperative bile duct leaks were more common with early intervention (3%) compared to delayed (0%).

What are the rates of conversion from laparoscopic to open during cholecystectomy for acute cholecystitis?

5-30%

These are greater in acute cholecystitis compared to uncomplicated cholelithiasis, but there is no difference between early and delayed intervention.

When should antibiotics be administered in the setting of cholecystitis?

Per the IDSA, a second-generation cephalosporin or a fluoroquinolone and metronidazole shold be administered in the following scenarios:
WBC greater than 12,500 or Temperature greater than 38.5C AND
Radiographic findings of cholecystitis
Also in elderly, diabetics, or immunocompromised

Patients undergoing cholecystectomy will also get a prophylactic perioperative dose, even if they don't require empiric treatment.

When should percutanous cholecystostomy tubes be used?

Patients with Grade 3/Severe cholecystitis
Septic shock
Poor surgical candidates

Delayed cholecystectomy may be considered at a later time.

Late... SG

References:
Strasberg SM. Acute Calculous Cholecystitis. NEJM 2008; 358: 2804-2811.

Square Knot Tutorial

It's been awhile... here's a sweet tutorial on knot tying.



Late... SG

Rectal Prolapse

What is the difference between procidentia and rectal mucosal prolapse?

Procidentia is a complete, full-thickness, rectal prolapse.

Procidentia can be differentiated by its circumferential, concentric folding pattern. Mucosal prolapse manifests with deep grooves with a radial pattern.

What patient population typically presents with rectal prolapse?

Older women

What studies may be useful in evaluation of rectal prolapse and disorders in defecation?

Colonic transit studies
Anorectal manometry
Pudendal nerve latency studies
Electromyography
Cinedefecography

What studies should be performed prior to operative intervention?

Colonoscopy or air-contrast barium enema

The colon should be assessed for neoplasms and diverticular disease.

What are the two primary surgical approaches to manage rectal prolapse?

1. Abdominal
2. Perineal

The abdominal approaches have lower recurrence rates, while perineal approaches have lower operative morbidity. There are also laparoscopic modifications that can potentially decrease surgical stress on the patient.

What procedures utilize the abdominal approach?

1. Rectopexy (suture or prosthetic)
2. Rectopexy with resection of redundant sigmoid

What procedures utilize the perineal approach?

1. The Delorme procedure
2. The Altemeier procedure
3. The Tiersch procedure

What is the Moschowitz repair?

Transabdominal reduction of a perineal hernia with closure of the cul-de-sac

What is the Ripstein repair?

A transabdominal rectopexy using an anterior mesh sling

What is the Wells repair?

A transabdominal rectopexy using a posterior mesh suspension

What is the Delorme procedure?

A transperineal mucosectomy

This is commonly performed for mucosal prolapse and is essentially a mucosal sleeve resection with plication of the muscularis.

What is the Altemeier procedure?

A transperineal rectosigmoidectomy

This involves eversion of redundant rectum with a full-thickness resection and anastomosis.

What is the Tiersch procedure?

An anal encirclement procedure that was originally described using a silver wire to encircle the external sphincter within the ischiorectal space, creating an outlet obstruction.

This is considered a palliative procedure, and has been done under local anesthesia using subcutaneously placed polypropylene mesh.

Late...SG

Sources:
Schwartz' Principles of Surgery, 8th ed.
Mastery of Surgery, 5th ed.

Electrosurgery

Who first demonstrated the principles of electrosurgery?

Alex d'Arsonval, a French physicist

Who first produced an electrosurgical unit designed for human use?

William Bovie, a Harvard biophysicist

Who popularized the use of "the Bovie"?

Harvey Cushing, MD, the father of modern neurosurgery

Cushing is reknown for developing surgical techniques that reduced the mortality rate of brain surgery from 90% to under 10%.

What is Cushing's Disease?

Secondary hypercortisolism, from a pituitary tumor leading to ACTH-hypersecretion.

Cushing's Syndrome is a more general term, referring to any form of symptomatic glucocorticoid excess, whether from an adrenocortical tumor, or exogenous steroids.

What prestigious award did Cushing receive in his academic career?

The Pulitzer Prize, for his biography "A Life of Sir William Osler"

What is Ohm's Law?

Voltage = Current * Resistance

What is Impedance?

A measure of resistance to flow when using alternating current (AC)

A high cellular water content results in a low tissue impedance.

What is Alternating Current?

Current that cycles in direction at a specific frequency... this comes from a typical US wall outlet at rates of 60Hz.

Electrocautery utilizes direct current (i.e. battery-powered hand-held units), while electrosurgical units utilize alternating current.

What radiofrequencies cause neuromuscular stimulation?

Up to 100kHz

What radiofrequencies cause a generation of heat?

200kHz - 5MHz

What is the Joule-Lenz Law?

Heat dissipated = (Current-density)squared * Resistance * time

Current-density is current divided by cross-sectional area.
Thus, heat generated with electrosurgery is inversely proportional to the area of the electrode and proportional to the time of contact and the impedance of the tissue.

What is monopolar current?

Electricity flowing from a single electrode to the patient.

Monopolar units typically utilize a pencil-type probe that is hand operated. Laparoscopic monopolar cautery may be operated by a foot pedal.

What is a dispersive electrode?

A ground or grounding pad.

Why is a ground pad placed on the patient when using monopolar cautery?

It allows completion of the electric circuit through the patient back to the electrosurgical unit.

Does the size of the ground pad matter?

By being large, it disperses current over a greater surface area. If it were small (i.e. detached/poor contact), it could cause generation of enough heat to create a local burn.

What is bipolar current?

Electricity flows in a closed circuit between two closely placed electrodes (i.e. bipolar forceps or scissors). Current flow and injury to tissue is limited to the region between the electrodes.

Bipolar units typically allow the use of a lower voltage waveform than monopolar units to acheive hemostasis.

What are common modes used by monopolar electrosurgical units?

1. Cutting
2. Coagulation
3. Blend

What are the properties of a cutting waveform?

It uses a continuous (pure sine-wave), low voltage, high-frequency waveform (500kHz) that concentrates energy on a small area.
Instantaneous heating (100 degrees C) results in cellular evaporation at contact, with minimal damage to surrounding tissues.

What are properties of a coagulation waveform?

It uses a pulsed, higher-voltage waveform that allows for dispersal of energy deeper into tissue.
Heating is less (37- 60 degrees C), causing tissue dessication and protein denaturing, allowing for sealing of blood vessels.

What is fulgaration?

Surface coagulation, accomplished by a non-contact method of electrocautery.

What are the properties of a blend mode?

This is a combination of cutting and coagulation waveforms. The higher the blend, the higher the coagulation effects.

What happens to tissue impedance during coagulation?

As water evaporates and tissue dessicates, the tissue impedance increases, leading to increased coagulative effect.

This can also increase the potential of arcing of the current to a lower impedance tissue, leading to iatrogenic injury.

Remember, current flows in the path of least resistance.

What are special hazards seen with laparoscopic electrosurgery?

1. Insulation failure
2. Direct coupling
3. Capacitor coupling

Injury can occur to non-target tissue out of view of the surgical team!

What is insulation failure?

When a defect in the covering of the active electrode allows current to contact non-target tissue.

What is direct coupling?

When the tip of the active electrode comes into contact with another metal instrument in the surgical field.

What is capacitor coupling?

When stray current from an electrode develops by a storage of charge. This can be minimized by activating the active electrode only when it is in contact with target tissues and limiting the amount of time on the coagulation setting.

This can sometimes occur with devices that contain both plastic and metal, allowing for insulation of charge by the instrument or trocar.

For a resource that has some pretty decent illustrations, consider this online course at Valleylab.

Late... SG

Sources:
O'Leary's Physiologic Basis of Surgery, 3rd ed.
Jones CM, Pierre KB, Nicoud IB, Stain SC, Melvin WV. Electrosurgery. Curr Surg 2006; 63: 458-463.

Aphorisms and Quotations

Here's a book for any quote enthusiast:

Aphorisms & Quotations for the Surgeon. Edited by Moshe Schein. tfm Publishing, Ltd. : Shrewsbury, UK; 2003.

For those of you who have been looking for a convenient resource to pepper your next powerpoint presentation with a breath of surgical history, this is the book for you. Even better if you are looking for a little inspiration at the end of the day. In addition to instilling the text with witticisms of his own, Moshe Schein has organized the numerous quotes into 94 different subject headings, ranging from the ubiquitous organ systems, to topics such as academics, dogma, greatness, love, money, politics, gimmicks, fame, ethics, empathy, and errors.

Here are a few:

There are 4 degrees of intra-operative hemorrhage:
1. "Why did I get involved in this operation?"
2. "Why did I become a surgeon?"
3. "Why did I study to become a doctor?"
4. "Why was I born?"
-Alexander A Artemiev

When I am carrying out a big, unusual, or difficult operation, I never plan anything later that day.
-Francis D. Moore

It is a most gratifying sign of the rapid progress of our time that our best textbooks become antiquated so quickly.
-Theodor Billroth

I would like to see the day when somebody would be appointed surgeon somewhere who had no hands, for the operative part is the least part of the work.
-Harvey W. Cushing

Medical examinations: they are no tests of the man. They are only tests for his memory for facts. They tell us nothing of his judgement, tact, energy, enthusiasm, idealism, reason, observation, temperament, disposition, honesty, loyalty, courage, truthfulness, or intelligence. Memory of facts means little. The other things mean nearly all.
-J. Chalmers Da Costa

The pleasure of a physician is little, the gratitude of patients is rare, and even rarer is material reward, but these things will never deter the student who feels the call within him.
-Theodor Billroth

You must always be students, learning and unlearning till your life's end, and if, gentlemen, you are not prepared to follow your profession in this spirit, I implore you to leave its ranks and betake yourself to some third-class trade.
-Joseph Lister

Late... SG