CHAPTER

43 Anesthesia for Laparoscopic and Robotic Surgeries

The development of “minimally invasive surgery” or “minimal access surgery” has revolutionized the field of surgery (Joshi GP, Cunningham A. Anesthesia for laparoscopic and robotic surgeries. In: Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Ortega R, Stock MC, eds. Clinical Anesthesia. Philadelphia: Lippincott Williams & Wilkins; 2013:1257–1273). The growth of laparoscopic surgical procedures is attributable to the use of smaller incisions that reduce surgical stress and postoperative pain and reduce overall morbidity, thus resulting in rapid recovery, earlier ambulation, shorter hospital stays, and a rapid return to daily living activities (Table 43-1). Robotic surgery improves depth perception through high-definition, magnified, and three-dimensional view of the operative field and is expected to broaden the application of the minimally invasive surgical paradigm. Despite the potential advantages of laparoscopic and robotic surgery, they are associated with significant physiologic changes as well as new complications (some potentially life threatening) that are usually not seen with the traditional “open” approach (Table 43-2). In addition, robotic procedures can have significantly prolonged operative times and require patients to be placed in extreme positions. In addition, because the robotic system is large, it limits the access to the patient and invades the anesthesia working space.

I. SURGICAL TECHNIQUES

A. Laparoscopic procedures entail intraperitoneal insufflation of carbon dioxide (CO₂) to create pneumoperitoneum that allows surgical exposure and manipulation. Carbon dioxide is used because it is noncombustible and more soluble in blood, which increases the safety margin and decreases the consequences of gas embolism. Unlike nitrous oxide (N₂O), CO₂ does not support combustion and, therefore, can be used safely with diathermy.

B. The initial access necessary for CO₂ insufflation could be achieved either through a blind insertion of a Veress (blunt-tipped, spring-loaded inner stylet and sharp outer needle through a small subumbilical incision) or a trocar inserted under direct vision (avoids dangers of blind insertion).

TABLE 43-1 ADVANTAGES OF MINIMALLY INVASIVE SURGERY

• Minimizes surgical incision and stress response

• Decreased postoperative pain and opioid requirements

• Preserves diaphragmatic function

• Improves postoperative pulmonary function

• Earlier return of bowel function

• Fewer wound-related complications

• Earlier ambulation

• Shorter hospital stays

• Earlier return to normal activities and work

• Reduced health costs

C. Upon confirmation of appropriate placement, a variable flow electronic insufflator that automatically terminates gas flow at a preset intra-abdominal pressure (IAP) is used to achieve pneumoperitoneum (maintain the IAP <15 mm Hg because higher pressures can have significant physiologic consequences).

1. An access port is then inserted in place of the needle to maintain insufflation during the procedure.

2. A video laparoscope, inserted through the port, allows visualization of the operative field.

3. Additional access ports are inserted through a number of small skin incisions, which allow the introduction of surgical dissection and suction instruments.

TABLE 43-2 POTENTIAL COMPLICATIONS DURING LAPAROSCOPY

• Creation of pneumoperitoneum (carbon dioxide insufflation and intra-abdominal pressure)

• Hemodynamic

• Pulmonary

• Neurohumoral responses

• Surgical instrumentation

• Injury (vascular, gastrointestinal, genitourinary, nervous system, thermal)

• Subcutaneous emphysema

• Capnothorax, capnomediastinum, capnopericardium

• Gas embolism

• Patient positioning

D. The Da Vinci Surgical System is the most common robotic platform.

1. Similar to a laparoscopic procedure, robotic surgery involves development of pneumoperitoneum and placement of video camera (a high-definition three-dimensional vision system) and ports.

2. This is followed by placement of the robotic arms, a crucial and tedious part of the procedure.

E. Patient position during minimally invasive surgery varies significantly based on the surgical procedure. (Upper abdominal procedures require a reverse Trendelenburg position, and lower abdominal procedures require Trendelenburg position.) These head-up or head-down positions can be steep.

II. PHYSIOLOGIC EFFECTS. The physiologic consequences of laparoscopy can be complex and depend on the interactions among the patient’s preexisting cardiopulmonary status and surgical factors such as the magnitude of IAP, degree of CO₂ absorption, alteration of patient position, and type of surgical procedure.

A. Cardiovascular Effects

1. The changes in the cardiovascular function during laparoscopy are attributable to the mechanical and neuroendocrine effects of pneumoperitoneum and the effects of absorbed CO₂ and patient positioning as well as patient factors such as cardiopulmonary status and intravascular volume (Table 43-3).

TABLE 43-3 HEMODYNAMIC EFFECTS OF MINIMALLY INVASIVE SURGERY

• Increased systemic vascular resistance and mean arterial pressure

• Causes: Hypercarbia, neuroendocrine response (increased catecholamines, vasopressin, cortisol), mechanical factors (direct compression of aorta)

• Increased or no change in cardiac filling pressures

• Causes: Compression of intra-abdominal organs (liver, spleen)

• Decreased or no change in cardiac index

• Causes: Increased afterload, decreased venous return and cardiac filling

• Cardiac dysrhythmias (bradycardia or tachycardia)

• Causes: Peritoneal stretch, hypercarbia, hypoxia, capnothorax, pulmonary embolism

2. The cardiovascular changes of laparoscopy include increase in systemic vascular resistance (SVR) and mean arterial pressure (MAP), which is caused by increased sympathetic output from CO₂ absorption and a neuroendocrine response to pneumoperitoneum.

3. Increased IAP may compress venous capacitance vessels, causing decrease in preload (cardiac filling volume), particularly in hypovolemic patients.

4. The hemodynamic changes that occur during abdominal robotic surgery appear to be similar to those observed during laparoscopic surgery.

a. Peritoneal insufflation and a steep (40-degree) head-down position during robotic-assisted prostatectomy increase SVR and MAP; other hemodynamic variables remain in acceptable limits.

b. Overall, robotic surgery appears to be well tolerated in a healthy population. However, the physiologic changes in elderly patients and in patients with impaired cardiopulmonary reserve undergoing robotic prostatectomy remains unknown.

B. Regional Perfusion (Splanchnic, Renal, Cerebral, and Intraocular)

1. Increased IAP, systemic CO₂ absorption, and changes in patient position along with the hemodynamic changes (SVR and cardiac index) influence splanchnic, renal, and cerebral blood flow during minimal-access surgery (Table 43-4).

2. The direct mechanical and neuroendocrine effects of pneumoperitoneum can decrease splanchnic circulation, causing reduced total hepatic blood flow and bowel circulation. However, these effects may be counter balanced by the direct splanchnic vasodilation caused by hypercapnia.

3. The mechanical compressive and neuroendocrine effects of pneumoperitoneum may account for reduction in renal blood flow, glomerular filtration, and urine output (Table 43-5).

TABLE 43-4 REGIONAL CIRCULATORY CHANGES DURING LAPAROSCOPY

• Increased cerebral perfusion and intracranial pressure

• Caution in patient with brain tumor or ventriculoperitoneal shunt

• Decreased splanchnic blood flow

• Decreased or no change in bowel perfusion (mechanical pneumoperitoneum compression balanced by hypercarbic vasodilation)

• Decreased hepatic blood flow (beneficial during cryoablation of liver metastasis)

• Reduced renal perfusion and urine output (reduced during pneumoperitoneum with recovery after deflation)

• Decreased femoral vein flow

• Increased potential for deep vein thrombosis and pulmonary embolism

TABLE 43-5 RENAL FUNCTION DURING LAPAROSCOPY

• Urine output reduced during laparoscopy

• Decreased renal blood flow

• Compression of renal parenchyma

• Neuroendocrine

• Factors that influence urine output

• Pre-existing renal compromise

• Longer insufflation times

• High IAP

• Intraoperative oliguria reversible within 2 h postoperatively

• IAP <15 mm Hg safe even in patients with renal disease

IAP = intra-abdominal pressure.

4. Increases in PaCO₂ during steep Trendelenburg positioning can increase cerebral blood flow and intracranial pressure with implications for patients with intracranial mass lesions.

5. Intraocular pressures increase significantly during robotic-assisted radical prostatectomy with steep head-down positions.

C. Respiratory and Gas Exchange Effects

1. Changes in pulmonary function during laparoscopy include reduction in lung volumes and pulmonary compliance secondary to cephalad displacement of the diaphragm caused by increased IAP and patient positioning (Table 43-6).

2. Reduction in functional residual capacity (FRC) and total lung compliance results in basal atelectasis and increased airway pressures.

3. The CO₂ insufflated into the peritoneal cavity is absorbed and causes hypercarbia.

a. The CO₂ absorption reaches a plateau within 10 to 15 minutes after initiation of intraperitoneal insufflation and thus is not influenced by the duration of surgery. However, it continues to increase progressively throughout extraperitoneal CO₂ insufflation.

TABLE 43-6 PULMONARY CHANGES DURING LAPAROSCOPY

• Elevated diaphragm

• Decreased lung volumes (functional residual capacity)

• Increased ventilation–perfusion mismatch

• Increased alveolar–arterial oxygen gradient

• Decreased lung compliance and increased resistance

• Increased pleural pressures

• Increased airway pressures

• Uneven gas distribution

• Cephalad displacement of carina

• Endobronchial intubation

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