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688

SECTION 5

Portal Hypertension

 

 

 

 

Preoperative Preparation During Acute Bleeding

 

 

Temporary hemostasis with intravenous infusion of octreotide (50mcg/h) or

 

 

vasopressin (0.2–0.4units/min)

 

 

Temporary hemostasis during endoscopy by injection sclerotherapy or banding

 

 

of esophageal varices

 

 

Restoration of blood volume by transfusion of packed red blood cells and fresh

 

 

frozen plasma through large-bore intravenous catheters

 

 

Prevention of portasystemic encephalopathy by instillation via nasogastric tube

 

 

of neomycin (4g), lactulose (30ml), and cathartics (60ml magnesium sulfate)

 

Correction of hypokalemia and metabolic alkalosis by intravenous administration

 

 

of large quantities of potassium chloride

 

 

Intravenous administration of hypertonic glucose solution containing therapeutic

 

 

doses of vitamins K, B, and C

 

 

Preoperative administration of antibiotics

 

 

Frequent monitoring of vital functions by an arterial catheter for blood pressure,

 

 

a central venous catheter, and a urinary bladder catheter. Serial measurements

 

 

of hematocrit, arterial pH and blood gases, and rate of blood loss by continuous

 

 

suction through a nasogastric tube

 

Portacaval Shunts: Side-To-Side and End-To-Side

689

 

 

 

 

Procedure

 

 

 

 

STEP 1

Position of patient

 

 

The patient is placed on the operating table with the right side elevated at an angle of 30°

 

 

to the table by two sandbags placed underneath the right posterior trunk. The costal

 

 

margin is at the level of the flexion break of the table, the right arm is suspended from

 

an ether screen with towels, and the left arm is extended on an arm board cephalad to

 

the ether screen. The table is “broken” at the level of the costal margin and at the knees

so as to widen the space between the right costal margin and right iliac crest, and to make it possible to perform the operation easily through a right subcostal incision (A1, A-2). The incision extends from the xiphoid to well into the flank and is made two

finger breadths below the costal margin. The skin is incised superficially with the scalpel and the other layers with the electrocautery, which greatly reduces the blood loss and shortens the operating time. When the electrocautery is used, it is usually unnecessary to clamp any blood vessels with hemostats. The right rectus abdominis, external oblique, and transverse abdominis muscles are completely divided and the medial 3–4cm of the latissimus dorsi muscle is incised. The peritoneum often contains many collateral veins and is incised with the electrocautery to obtain immediate hemostasis.

A-1

A-2

690

SECTION 5

Portal Hypertension

 

 

 

STEP 2

Exposure of operative field

 

 

 

 

The operative field is exposed by retraction of the viscera with three Deaver retractors positioned at right angles to each other. The inferior one retracts the hepatic flexure of the colon toward the feet, the medial one displaces the descending duodenum medially and the superior retractor retracts the liver and gallbladder toward the head. Alternatively, a self-retaining retractor may be used to accomplish the same exposure. The posterior peritoneum is often intensely “stained” with portasystemic collateral veins.

Portacaval Shunts: Side-To-Side and End-To-Side

691

 

 

 

STEP 3

Isolation of inferior vena cava

 

 

 

 

The inferior vena cava (IVC) lies behind the descending duodenum. The posterior peritoneum overlying the IVC is incised with the electrocautery by an extended Kocher maneuver just lateral to the descending duodenum, and the retractors are repositioned to retract the head of the pancreas medially and the right kidney caudally. The peritoneum is often greatly thickened and contains many collateral veins. Bleeding usually can be controlled with the electrocautery but sometimes requires suture ligatures.

The anterior surface of the IVC is cleared of fibroareolar tissue, and the IVC is isolated around its entire circumference by blunt and sharp dissection from the entrance of the right and left renal veins, below, to the point where it disappears behind the liver, above. The IVC is encircled with an umbilical tape. To accomplish the isolation, several tributaries must be ligated in continuity with fine silk ligatures and then divided. These tributaries often include the right adrenal vein, one or two pairs of lumbar veins that enter on the posterior surface, and the caudal pair of small hepatic veins from the caudate lobe of the liver that enter on the anterior surface of the IVC directly from the liver.

692

SECTION 5

Portal Hypertension

 

 

 

STEP 4

Testing adequacy of IVC mobilization

 

 

 

 

When the IVC has been mobilized completely, it can be lifted up toward the portal vein. Failure to isolate the IVC circumferentially is one major reason for the erroneous claim that the side-to-side portacaval shunt often cannot be performed because the portal vein and IVC are too widely separated.

Portacaval Shunts: Side-To-Side and End-To-Side

693

 

 

 

STEP 5

Isolation of portal vein

 

 

 

 

The superior retractor is repositioned medially so that it retracts the liver at the point of entrance of the portal triad. The portal vein is located in the posterolateral aspect of the portal triad and is approached from behind. The fibrofatty tissue on the posterolateral aspect of the portal triad, which contains nerves, lymphatics, and lymph nodes, is divided by blunt and sharp dissection. This technique is a safe maneuver because there are no portal venous tributaries on this aspect of the portal triad. As soon as the surface of the portal vein is exposed, a vein retractor or Gilbernet retractor is inserted to retract the common bile duct medially. The portal vein is mobilized circumferentially at its midportion and is encircled with an umbilical tape. It then is isolated up to its bifurcation in the liver hilum. Several tributaries on the medial aspect are ligated in continuity with fine silk and divided.

694

SECTION 5

Portal Hypertension

 

 

 

STEP 6

Mobilization of portal vein behind pancreas

 

 

 

 

Using the umbilical tape to pull the portal vein out of its bed, the portal vein is cleared to the point where it disappears behind the pancreas. The tough fibrofatty tissue that binds the portal vein to the pancreas must be divided. Several tributaries that enter the medial aspect of the portal vein and one tributary that enters the posterolateral aspect are divided. It is usually not necessary to divide the splenic vein. Wide mobilization of the portal vein is essential for performance of a side-to-side portacaval anastomosis. Failure to mobilize the portal vein behind the pancreas is a second major reason for difficulty in accomplishing the side-to-side shunt. In some patients, it is necessary to divide a bit of the head of the pancreas between right-angled clamps to obtain adequate mobilization of the portal vein. Bleeding from the edges of the divided pancreas is controlled with suture ligatures. Division of a small amount of the pancreas is a very helpful maneuver and we have never observed postoperative complications, such as pancreatitis, from its performance. Before incising the pancreas, the surgeon should insert his or her index finger into the tunnel between the portal vein and the pancreas to determine by palpation if there is a replaced common hepatic or right hepatic artery arising from the superior mesenteric artery and crossing the portal vein. Since the portal venous blood flow to the liver is diverted through the portacaval shunt, ligation of the hepatic arterial blood supply may be lethal.

Portacaval Shunts: Side-To-Side and End-To-Side

695

 

 

 

STEP 7

Testing adequacy of mobilization of portal vein and IVC

 

 

 

 

To determine the adequacy of mobilization of portal vein and IVC, the two vessels are brought together by traction on the umbilical tapes that surround them . It is essential to determine that the two vessels can be brought together without excessive tension.

If this cannot be done, it is almost always because the vessels have not been adequately mobilized, and further dissection of the vessels should be undertaken. Resection of part of an enlarged caudate lobe of the cirrhotic liver, recommended by some surgeons to facilitate bringing the vessels together, is associated with some difficulties and, in our opinion, is neither necessary nor advisable.

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SECTION 5

Portal Hypertension

 

 

 

STEP 8

Measurement of venous pressures

 

 

 

 

Pressures in the IVC and portal vein are measured with a saline (spinal) manometer by direct needle puncture before performance of the portacaval anastomosis. For all pressure measurements, the bottom of the manometer is positioned at the level of the IVC, which is marked on the skin surface of the body with a towel clip (A-1 to A-5). All portal pressures are corrected by subtracting the IVC pressure from the portal pressure.

A portal vein-IVC pressure gradient, also known as the corrected free portal pressure, of 150mm saline or higher, represents clinically significant portal hypertension. Most patients with bleeding esophageal varices have a portal vein-IVC gradient of 200mm saline or higher. The pressure measurements include:

IVCP – inferior vena caval pressure

FPP – free portal pressure

HOPP – hepatic occluded portal pressure, obtained on the hepatic side of a clamp occluding the portal vein

SOPP – splanchnic occluded portal pressure, obtained on the intestinal side of a clamp occluding the portal vein

In normal humans, HOPP is much lower than FPP, and SOPP is much higher. In patients with portal hypertension, the finding of an HOPP that is higher than the FPP suggests the possibility that blood flow in the portal vein is reversed because of severe hepatic outflow obstruction.

A-1

A-3

A-2

Portacaval Shunts: Side-To-Side and End-To-Side

697

 

 

 

STEP 8 (continued)

Measurement of venous pressures

 

 

 

 

A-4

A-5