Carcinoma of the prostate is the most frequently diagnosed cancer (except for skin cancer) in American men. In 1983, the incidence of carcinoma of the prostate was approximately 75,000 new cases along with 25,000 deaths of old cases. In 2014, the American Cancer Society estimates that the newly diagnosed incidence will be 233,000 (or 27% of all new cancers) and 29,480 deaths in existing cases (or 10% of all cancer deaths).

This “epidemic” increase in carcinoma of the prostate stems from widespread use of the PSA blood test to detect the disease earlier rather than from a true rise in incidence of the disease. Undetected microscopic prostate cancer cells are believed to be present in 30% to 40% of men older than the age of 50 years and in 75% of men older than the age of 75 years, but it is estimated that only approximately 8% of these men will develop clinically significant disease. It has been stated that more men die with prostate cancer than from it. Therefore, it is not yet known whether early detection of subclinical disease, much of which may have remained clinically insignificant, will improve survival.

Carcinoma of the prostate is rare in Asian men, whereas African-American men have about twice the incidence as white American men.

The most reliable methods for diagnosis include a digital rectal examination plus the serum PSA level. Palpation of a tumor or indurated area and finding an elevated PSA should be followed by prostatic needle biopsies, perhaps under transrectal ultrasound guidance.

Treatment choices vary not only with the stage of the disease but also with the patient’s age and life expectancy, associated medical conditions, and lifestyle. In patients with localized disease, treatment choices include “watchful waiting,” brachytherapy (in which radioactive seeds are implanted in the prostate gland), radiation (including external beam, intensity modulated radiation therapy, stereotactic therapy, proton beam therapy, etc.), cryosurgery, vaccine therapy, and other nonsurgical treatments. Surgical options include traditional open radical prostatectomy performed through either a retropubic (lower abdominal) or perineal incision or laparoscopic radical prostatectomy, which can be hand-assisted or robot-assisted.

A patient with nonlocalized disease may choose to be treated with radiation, hormones, chemotherapy, other nonsurgical options, or even to have no treatment.

Laparoscopy (or peritoneoscopy) is a “minimally invasive” procedure allowing endoscopic access to the peritoneal cavity after insufflation of a gas (CO₂) to create space between the anterior abdominal wall and the viscera. The space is necessary for the safe manipulation of instruments and organs. Laparoscopic surgery can also be extraperitoneal. It can also be gasless with abdominal wall retraction, and more recently, it may be hand-assisted or robotically assisted.

The era of open incisions in which surgeons could directly see, touch, and manipulate organs was superseded by minimally invasive surgery in which tiny cameras and laparoscopes could be inserted through small ports in the patient’s body. However, conventional laparoscopy is limited by poor depth perception (visualization on a two-dimensional monitor) and the use of long, straight instruments that limit mobility and dexterity.

Robotic devices were initially designed by National Aeronautics and Space Administration (NASA) for the purpose of performing tasks outside the Space Shuttle while being controlled remotely from inside the spacecraft or from earth. This technology was adapted for surgery as the Da Vinci computer-assisted robotic system.

The surgeon sits at a remote control console near the patient and operating room table and views the operative field as a high-resolution magnified three-dimensional image transmitted from a video camera. By using hand-and-finger control devices, the surgeon can precisely manipulate the mechanical arms of the robot to achieve wrist-like motion. Foot pedals also allow the surgeon to more precisely control the robot, camera, and cautery.

The advantages include the cosmetic results of small, non-muscle-splitting incisions, decreased blood loss, less postoperative pain and ileus, shorter hospitalization and convalescence, and ultimately lower cost. Postoperative respiratory muscle function returns to normal more quickly than in open surgery, especially in laparoscopic cholecystectomy and other upper abdominal procedures. Wound complications such as infection and dehiscence are less frequent, and host defense mechanisms may be greater in laparoscopic than in open surgery.

The disadvantages include the long learning curve for the surgeon (most complications occur during the first 10 laparoscopies), the narrowed two-dimensional visual field on video in conventional laparoscopy, the need for general anesthesia, and the potentially longer operative duration. Ideally, surgeons should have more advanced laparoscopic skills, especially in knot tying, suturing, and working two instruments simultaneously. The use of simulators to enhance these skills has been advocated.

Robotic-assisted laparoscopy, by virtue of its high-resolution three-dimensional visualization and greater precision, offers a greater likelihood of nerve sparing in prostatectomy and, therefore, retention of continence and potency. The disadvantages of the robot include added
operative time, the high cost (in millions of dollars) of equipment purchase and maintenance, and the need for a permanently dedicated operating room location for this heavy and bulky equipment.

Robot-assisted laparoscopic radical prostatectomy is now the most commonly performed robotic surgery in the United States.

Pulmonary function is substantially impaired after a large upper abdominal or subcostal muscle-splitting incision, as in open cholecystectomy. Marked diaphragmatic dysfunction occurs postoperatively due to both reflex diaphragmatic changes and incisional pain. Vital capacity and functional residual capacity (FRC) may be reduced by 20% to 40% of preoperative values, and they may not return to normal until 2 to 3 days after surgery. The mini-incision of laparoscopic cholecystectomy results in far less pulmonary and diaphragmatic loss of function as well as less ileus.

Increasing experience with the laparoscopic technique has made most contraindications relative rather than absolute. However, it is probably best to avoid or to use extreme caution in patients with a coagulopathy, a diaphragmatic hernia, severe cardiovascular or pulmonary disease (including bullae), increased intracranial pressure or space-occupying masses, a retinal detachment, impending renal shutdown, a history of extensive surgery or adhesions, sickle cell disease (because sickle crisis may be precipitated by acidosis), peritonitis, a large intra-abdominal mass, a tumor of the abdominal wall, or hypovolemic shock. Patients with shunts (e.g., ventriculoperitoneal) are at risk for gas emboli, shunt obstruction, and intracranial hypertension, all of which may occur during laparoscopy and may require intracranial pressure monitoring and ventricular drainage if laparoscopic surgery is necessary. In summary, most of the contraindications concern patients who are unable to tolerate extremes of position, pneumoperitoneum, and/or hypercarbia.

Although pregnancy has been considered a contraindication to laparoscopic surgery in the past, an increasing number of such procedures are being performed in the parturient. Laparoscopic cholecystectomy is now more frequent than open cholecystectomy in the pregnant patient. The overall objective of laparoscopic and open surgery is to preserve fetal and maternal well-being and to prevent premature labor. In addition to the general problems of anesthesia for the parturient, the anesthesiologist also must consider the specific problems that result from the interplay between the anatomic and physiologic changes of pregnancy and the anatomic and physiologic triad of pneumoperitoneum, hypercarbia, and positional changes.

Factors to consider in the management of the pregnant patient include awareness of her increased blood volume, increased cardiac output, decreased systemic vascular resistance (SVR), hypercoagulability, the supine hypotensive syndrome, increased respiratory minute volume, decreased residual volume, decreased FRC, increased oxygen consumption, mild hypocapnia, increased risk of aspiration, and decreased anesthetic requirement. This combination of factors tends to promote hypercarbia and hypoxemia. However, extreme
hyperventilation may result in decreased uteroplacental perfusion. Arterial blood gas monitoring has been suggested to detect fetal acidosis because capnography may not reveal a large arterial to end-tidal difference in CO₂. In all cases, preoperative and postoperative fetal and uterine monitoring is essential.

Laparoscopic procedures in urology have become standard, especially for prostatectomy, uncomplicated adrenalectomy, and nephrectomy, including live donor nephrectomy. Laparoscopic gynecologic surgery includes tubal surgery (sterilization, treatment of ectopic pregnancy, etc.), cystectomies, hysterectomies, various ablations (endometriosis), and so on. Laparoscopy is performed in pregnancy and also in pediatrics.

Laparoscopic general surgery includes cholecystectomy, hernia repair, antireflux procedures, splenectomy, appendectomy, bowel surgery including bariatric procedures, and various other upper and lower abdominal procedures.

Thoracoscopic, cardiovascular, and neurosurgical intracranial surgery, using modified laparoscopic instruments without the need for gas insufflation, are some of the more recent areas of endoscopic surgery. Lumbar discectomies and other types of spinal surgery also have been done laparoscopically through an anterior approach. Even autopsies have been attempted laparoscopically. The list continues to grow.

CO₂ is the insufflating gas of choice because it is nonflammable, does not support combustion, readily diffuses across membranes, is rapidly removed in the lungs, and is highly soluble because of rapid buffering in whole blood. The risk of CO₂ embolization is small. As much as 200 mL of CO₂ injected directly into a peripheral vein may not be lethal, whereas only 20 mL of air may prove to be so. In addition, CO₂ levels in blood and expired air can easily be measured, and its elimination can be facilitated by increasing ventilation. As long as oxygen requirements are met, a high concentration of blood CO₂ can be tolerated. Also, medical grade CO₂ is readily available and inexpensive.

It is for these reasons that the following gases are unsatisfactory for pneumoperitoneum: nitrous oxide (does not cause pain intra-abdominally but does not suppress combustion); oxygen (flammable); helium, air, and nitrogen (each has no hemodynamic or acid-base sequelae but can cause gas emboli); and argon (adverse effect on hepatic blood flow, emboli).

It should be emphasized, however, that CO₂ plays a dual role in the body, and it is not inert. Under normal circumstances, it is an intrinsic waste product of metabolism. During laparoscopic surgery, it acts as an extrinsic drug often present in quantities far larger than the body is physiologically capable of generating even with the most extreme exercise or hypermetabolic state.

The disadvantages mainly stem from the fact that CO₂ is not inert, and it has contradictory roles as an endogenous chemical and as an exogenous foreign substance. Changes in its concentration and tensions have enormous biochemical and physiologic consequences. Changes at the local tissue level are often at odds with the overall systemic effect. It causes direct peritoneal irritation and pain during laparoscopy under local anesthesia because it transiently forms carbonic acid when in contact with the moist peritoneum. In addition,
CO₂ is not very soluble in the absence of red blood cells, and therefore, it can remain in gaseous form intraperitoneally (subhepatic) after laparoscopy, causing referred shoulder pain. Hypercarbia and respiratory acidosis occur when the buffering capacity of blood is temporarily exceeded. In addition, CO₂ exerts widespread local and systemic effects that may manifest overall as hypertension, tachycardia, cerebral vasodilation, hypercarbia, and respiratory acidosis.

CO₂ and water are the major end products of aerobic metabolism in the mitochondria of the cells. Carbonic acid, the major acid produced in the body, is uniquely volatile, and therefore, it must be eliminated mainly by the lungs. (Other acids are eliminated by the kidney.)

At basal rate, an average adult manufactures approximately 200 mL of CO₂ per minute (while consuming 250 mL of O₂) or 12 L of CO₂ (35 g) per hour. At maximal metabolic rate, it is estimated that the body can produce, transport, and excrete 90 to 100 L per hour, an 800% increase over the basal rate.

The body contains approximately 120 L of stored CO₂, most of it in the form of carbonate ion in bone. (This is approximately 100 times the amount of stored oxygen.) CO₂ in the blood is in equilibrium with CO₂ in different tissues. The rate of uptake and distribution of CO₂ from the blood (where it exists as bicarbonate ion) depends on the perfusion and storage capacity of those different tissues. The well-perfused tissues, including brain, kidneys, and blood, come to rapid equilibrium. The medium-perfused compartment consists mainly of resting skeletal muscle. The slowly perfused compartment, mainly fat and bone (where it exists as the carbonate ion), has the largest CO₂ storage capacity. In contrast to rapidly changing oxygen levels, CO₂ levels reach equilibrium more slowly.

These storage sites serve to buffer and stabilize blood CO₂ levels because they provide a place for excess CO₂ to “park” until ventilation can catch up and restore equilibrium. The increase in CO₂ storage during laparoscopy is illustrated clinically by the decelerating rate of rise in PETCO₂ despite continuing insufflation. Blood or end-tidal CO₂ levels increase rapidly at first and plateau between 15 and 35 minutes despite continuing low flow insufflation. At constant ventilation, CO₂ levels increase but not as much as if no simultaneous storage processes were occurring. But if ventilation is increased to keep CO₂ constant, then the increase needed is only approximately 40% of the predicted volume of ventilation because of the drain off of CO₂ into the storage sites.

Diffusion describes the process by which gases travel from an area of higher partial pressure to one of lower partial pressure. For a gaseous environment, Graham’s law states that the rate of diffusion of a gas is inversely proportional to the square root of its density (i.e., the smaller the molecule, the more easily it will diffuse).

When that same gas molecule arrives at an aqueous membrane (e.g., a gas-liquid interface), the solubility of that gas in water now becomes the major factor in determining its diffusing capacity (as shown in Table 26.1). The water solubility of CO₂ is 24 times that of O₂, whereas the diffusion capacity of CO₂ is 20.5 times that of O₂. The capacity of a gas to diffuse across an aqueous membrane is directly proportional to its solubility in water and inversely proportional to its molecular weight. However, the actual movement of that gas across the aqueous membrane depends not only on its diffusing capacity but also more importantly on the pressure gradient across that membrane (Table 26.1).

The fate of CO₂ gas insufflated into the peritoneal cavity is the same that would occur in any other closed but distensible cavity. The pressure obtained within the cavity varies directly with the volume of gas insufflated and indirectly with the compliance of the closed cavity. Therefore, the ability of CO₂ to move from the closed peritoneal cavity to the lungs for excretion is dependent on its intrinsic diffusion and solubility properties, the rate of continuing CO₂ insufflation, the surface area of the cavity, and the partial pressure difference across membranes.

CO₂ is relatively insoluble in plasma, interstitial fluid, and water. (Think of the rapid escape of gas from a freshly opened carbonated soft drink.) The solubility of CO₂ in water at 37°C (98.6°F) is only 0.03 mmol/L/mm Hg. This must be contrasted to the very high solubility of CO₂ in whole blood. This extremely important distinction exists because of a zinc-containing enzyme, carbonic anhydrase, that exists within the erythrocyte but not at all in plasma.

In the equation shown, carbonic anhydrase catalyzes the left side of the equation (i.e., the hydration of CO₂ to H₂CO₃). Once formed, carbonic acid is unstable and immediately dissociates into H⁺ and . It is estimated that without carbonic anhydrase, it would take 200 seconds at 38°C (100.4°F) for the previous reaction to come to 10% equilibrium. Because blood travels through the pulmonary capillaries in less than 1 second, carbonic anhydrase speeds up the reaction by a factor of 7,500 times.

Carbonic anhydrase, therefore, allows the insufflated CO₂ gas to be dissolved and carried as bicarbonate in the blood. The process is reversed in the lungs, and the reconstituted CO₂ gas is removed by respiration.

All patient comorbidities must be evaluated to ensure optimal pharmacologic management preoperatively. Because of this patient’s advanced age, it is best to form one’s own observations of his mental and physical condition. Is he confused, short of breath, kyphoscoliotic, and so forth? A glimpse at where and how this patient’s body weight is distributed means more than just knowing that he weighs 120 kg. Ask about smoking, wheezing, any change in exercise tolerance, cough, recent upper respiratory infection, or change in medications. Perform your usual preoperative evaluation and obtain any consultations that may be informative. Consult with the surgeon regarding the need for appropriate preoperative antibiotics. Find out when his retinal detachments were repaired and if intraocular gas was used.

Basic tests should include complete blood count, urinalysis, clotting functions, electrocardiogram (ECG), and blood typing and screening. In addition, baseline electrolytes, chemistries, and renal function tests (blood urea nitrogen, creatinine) should be obtained because of the possibility of oliguria during a long laparoscopy. Baseline pulmonary function tests, arterial blood gas measurement, and oxygen saturation values while breathing room air would be helpful in this patient. Markedly abnormal values might suggest the need for
bronchodilators, antibiotics, postural drainage, and delay in surgery until pulmonary function is optimal for this particular patient. Baseline chest films are necessary not only to rule out active disease but also for postoperative comparison of acute changes such as subcutaneous or mediastinal emphysema, pneumothorax, or interstitial or pulmonary edema. The presence of bullae on preoperative chest x-ray films may represent a contraindication to laparoscopic surgery because of the accompanying large tidal volumes and high intrathoracic pressures.

In patients with cardiac issues, echocardiogram, stress test, and cardiology clearance may be advisable.

In addition to the usual general complications of the planned surgery and anesthesia, the patient must also be told of the complications unique to robotic laparoscopy, and consent for possible laparotomy must be obtained. Emergency laparotomy may be required in the event of complications such as hemorrhage, organ perforation, or anatomic or technical difficulties. The patient should also be told about the possibility of having postoperative referred shoulder pain.

Although the surgery is described as minimally invasive, the patient must be ready for maximally invasive surgery if necessary. Therefore, the patient must comply with preoperative orders regarding the following: