Anesthesia for Laparoscopic and Robotic Surgeries

Anesthesia for Laparoscopic and Robotic Surgeries

Girish P. Joshi

Anthony Cunningham


The development of “minimally invasive surgery” or “minimal access surgery” has revolutionized the field of surgery. The growth of laparoscopic surgical procedures is due to the use of smaller incisions that reduce surgical stress and postoperative pain as well as reduce overall morbidity, thus resulting in rapid recovery, earlier ambulation, shorter hospital stay, and rapid return to daily living activities (Table 43-1). These benefits are achieved without compromising surgical outcomes.1,2,3,4,5,6 In addition, a minimally invasive approach has allowed several procedures to be performed on an outpatient basis, where previously a hospital stay was necessary.7,8,9,10,11 Furthermore, it has allowed the implementation of rapid rehabilitation recovery programs that have been shown to further improve perioperative outcome and reduce hospital stay.12 Overall, there is potential for significant cost savings.

With growing surgical expertise and continuing improvements in technology, more extensive laparoscopic procedures are being performed in a wide range of patients, including morbidly obese, older, and sicker patients with significant comorbidities as well as pregnant and pediatric patients.1 However, conventional laparoscopy has several technical limitations, such as reduced range of motion and instrument dexterity as well as a two-dimensional view of the operative field.6 Technologic advances in computer power and robotic engineering have allowed us to address some of these limitations. Robotic surgery improves depth perception through a high-definition, magnified, and three-dimensional view of the operative field and provides intuitive instrument control that mimics natural hand and wrist movements and eliminates surgeon tremor. Overall, robotic surgery enhances surgeons’ skills and thus has the potential to transform technically challenging open or laparoscopic procedures, particularly those requiring improved visualization and/or complex reconstruction necessitating extensive suturing, into technically feasible minimally invasive procedures. Robotic surgery can be applied to virtually every surgical subspecialty (e.g., general, colorectal, head and neck, gynecologic, thoracic, and cardiac surgeries). The advantages of robotic surgery are expected to broaden the application of the minimally invasive surgical paradigm.

Table 43-1. Advantages of Minimally Invasive Surgery

  • Minimizes surgical incision and stress response
  • Decreases 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
  • Early return to normal activities and work
  • Reduces health costs

Despite the potential advantages of laparoscopic and robotic surgeries, 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 1 (Table 43-2). In addition, robotic procedures can have significantly prolonged operative times and require patients to be placed in extreme positions. Because the robotic system is large, it limits the access to the patient and invades the anesthesia working space. Overall, this presents significant challenges in anesthetic management. Therefore, a thorough understanding of potential physiologic changes and perioperative complications associated with laparoscopic and robotic surgeries is necessary to provide optimal patient care and improve perioperative morbidity and mortality.

This chapter discusses the anesthetic management of adult patients undergoing laparoscopic and abdominal robotic surgeries. However, endoscopic and robotic cardiac and thoracic surgeries (e.g., video-assisted thoracic surgery [VATS]) that are increasingly performed are discussed elsewhere (Chapter 37).

Surgical Techniques

Laparoscopic procedure entails 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. Compared to helium, the high blood solubility of CO2 and its capability for pulmonary excretion reduce the risk of adverse outcomes in the event of gas embolism. An abdominal wall lift system (i.e., a gasless laparoscopy) has been developed to achieve surgical space while avoiding the cardiopulmonary effects of CO2 pneumoperitoneum.13 Although this approach appears to be safe,
it has not been accepted in routine clinical practice because it increases operating times and surgical costs without improving clinical outcomes.13

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, thermal
    • Subcutaneous emphysema
    • Capnothorax, capnomediastinum, capnopericardium
    • Gas embolism

  • Patient positioning

Figure 43.1. A control console where the surgeon is stationed and operates the robotic arms and camera. © 2012 Intuitive Surgical, Inc.

The initial access necessary for CO2 insufflation could be achieved either through a blind insertion of a Veress needle that consists of a blunt-tipped, spring-loaded inner stylet and sharp outer needle through a small subumbilical incision or a trocar inserted under direct vision. The open insertion of the trocar using a minilaparotomy approach guarantees safe creation of pneumoperitoneum and avoids the dangers of blind insertion.

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. It is standard of care to maintain the IAP below 15 mm Hg, because higher pressures can have significant physiologic consequences and can increase the incidence of intraoperative complications. An access port is then inserted in place of the needle to maintain insufflation during the procedure. A video laparoscope, inserted through the port, allows visualization of the operative field. Additional access ports are inserted through a number of small skin incisions, which allow the introduction of surgical dissection and suction instruments. The secondary ports are placed under direct vision, preferably with the help of transillumination of the abdominal wall to identify superficial abdominal wall vessels.

The Da Vinci Surgical System (Intuitive Surgical Inc., Sunnyvale, California) is the most common robotic platform used currently. It consists of three components: a control console where the surgeon sits and operates the robotic arms and camera (Fig. 43-1), an equipment tower that includes an optical system, and the patient side cart that includes robotic arms.3,4,6 Similar to a laparoscopic procedure, robotic surgery involves development of pneumoperitoneum and placement of a video camera (a high-definition three-dimensional vision system) and ports. This is followed by placement of the robotic arms, a crucial and tedious part of the procedure (Fig. 43-2). An assistant is at the patient side for suctioning, retraction, and passage of suture or sponges.

Patient position during minimally invasive surgery varies significantly based on the surgical procedure. Patients undergoing upper abdominal procedures require a reverse Trendelenburg (head-up) position, while those undergoing lower abdominal procedures require Trendelenburg (head-down) position. The head-up or head-down position can be steep. In addition, the operating tables may be rotated laterally (right or left lateral) to further facilitate surgical exposure. Also, patients undergoing pelvic surgery (e.g., radial prostatectomy and hysterectomy) may be placed in a lithotomy position. Patients undergoing urologic surgery, particularly renal procedures, may be placed in lateral or semilateral positions combined with a flexion (i.e., jackknife) position. The considerations related to patient positioning are discussed in Chapter 28.

Physiologic Effects

The physiologic consequences of laparoscopy can be complex and depend on the interactions between the patient’s pre-existing cardiopulmonary status and surgical factors such as the magnitude of IAP, degree of CO2 absorption, alteration of patient position, and the type of surgical procedure.2,14,15 In addition, the anesthetic technique may influence the physiologic changes; however, these effects may be minimal with modern anesthetic techniques. Of note, physiologic changes are well tolerated by most healthy patients; however, they could have adverse consequences in patients with limited cardiopulmonary reserve.

Cardiovascular Effects

The changes in the cardiovascular function during laparoscopy are due 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). The induction of pneumoperitoneum in the supine position (rather than head-down position) and limiting the IAP to 12 to 15 mm Hg minimize the alterations in cardiovascular function during laparoscopy.2,14

The cardiovascular changes of laparoscopy include an 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.2,14,15 Pneumoperitoneum-related increased IAP results in activation of the sympathetic system with catecholamine release and the renin–angiotensin system with vasopressin release.16 The profile of vasopressin release parallels the time course of changes
in SVR. In addition, compression of the arterial vasculature from increased IAP may also lead to an increase in SVR. These neuroendocrine and mechanical responses supersede the hypercapnia-induced arteriolar dilation and decrease SVR. The increase in SVR may increase the myocardial wall tension and, thus, may increase the myocardial oxygen demand. However, myocardial ischemia, as suggested by electrocardiogram-ST–segment changes, is not observed.17

Figure 43.2. Layout of the operating room during robotic surgery. Reproduced from:.

Table 43-3. Hemodynamic Effects of Minimally Invasive Surgery

  • Increased systemic vascular resistance and mean arterial pressure

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

  • Variable change (increased or no change) in cardiac filling volumes

    • Causes: Compression of intra-abdominal organs (i.e., liver and spleen)

  • Variable change (decreased or no change) in cardiac index

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

  • Cardiac dysrhythmias (brady- or tachycardia)

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

The changes in cardiac filling pressures and volumes during laparoscopy appear to be complex. Increased cardiac filling pressures may reflect increased intrathoracic pressures caused by pneumoperitoneum and increased sympathetic output due to hypercapnia from CO2 absorption and surgical stress. However, cardiac filling pressures may not always reflect cardiac filling volumes. Increased IAP may compress venous capacitance vessels, causing a decrease in preload (cardiac filling volume), particularly in hypovolemic patients. In contrast, compression of the abdominal organs (e.g., liver and spleen) caused by increased IAP may increase intravascular volume, which may increase cardiac filling, particularly if the patient is placed in a head-down position.18 Overall, the cardiac filling pressures and volumes increase, but minimally.

In healthy patients, the changes in cardiac index (CI) appear to be phasic with initial reduction after induction of pneumoperitoneum and subsequent recovery within 10 to 15 minutes. Overall, the changes in CI in healthy patients are minimal. However, in patients with severe cardiac dysfunctions, there may be a significant reduction in CI and significant hemodynamic deterioration.19 Although reduction in CI parallels the time course of increase in SVR, the cause–effect relationship between SVR and CI is unclear. In addition, significant hypercapnia and associated respiratory acidosis may decrease myocardial contractility and lower the arrhythmia threshold. Hypercarbia can cause pulmonary vasoconstriction, which may be deleterious in patients with pulmonary hypertension or right ventricular dysfunction.

In the morbidly obese, the hemodynamic changes are similar to those observed in the nonobese.20,21 Although the reasons for this observation are not clear, it is hypothesized that lack of differences in hemodynamics may be related to intrinsically higher IAP in the obese (10 mm Hg vs. 5 mm Hg in the nonobese).

In the elderly, with significant coexisting cardiopulmonary disease, pneumoperitoneum and head-down position cause several hemodynamic changes.22 Induction of pneumoperitoneum significantly increased SVR accompanied with a significant reduction in CI and ejection fraction (EF). However, the left ventricular workload remained unchanged. Upon placement in the head-down position, the cardiac preload, as determined by the left ventricular end-diastolic area, increased and CI and EF improved.22 Oxygenation and ventilation remained unchanged, and no patients exhibited electrocardiogram signs of myocardial ischemia. Release of pneumoperitoneum resulted in a significant decrease in SVR and increased CI and left ventricular systolic work index.

The type of surgical procedure may also influence the degree of hemodynamic derangement. Surgical disruption of the esophageal hiatus during laparoscopic fundoplication may increase mediastinal and pleural pressures, resulting in a significant reduction in CI.23,24 Patients undergoing endoscopic radical prostatectomy in the Trendelenburg position did not experience hemodynamic changes, despite prolonged duration (average 4 hours) of pneumoperitoneum.25

The hemodynamic changes that occur during abdominal robotic surgery appear to be similar to those observed during laparoscopic surgery. Most of the studies evaluating such changes are performed in patients undergoing prostatectomy with steep head-down position. Peritoneal insufflation and steep (40 degrees) head-down position during robotic-assisted prostatectomy increase SVR and MAP, while other hemodynamic variables remain in acceptable limits26,27 (Figs. 43-3 and 43-4). A recent study found that although cardiac filling pressures were increased, the cardiac performance (stroke volume, cardiac output, and mixed venous oxygen saturation as well as
echocardiographic cardiac dimensions) was maintained during robotic-assisted prostatectomy with patients in 45-degree head-down tilt and pneumoperitoneum with IAP 12 mm Hg28 (Fig. 43-5). Overall, robotic surgery appears to be well tolerated in a healthy population. However, the physiologic changes in the elderly or in patients with impaired cardiopulmonary reserve undergoing robotic prostatectomy remain unknown.

Figure 43.3. Hemodynamic changes (heart rate (HR), mean arterial pressures (MAPs), central venous pressures (CVPs), cerebral perfusion pressure (CPP), arterial oxygen saturation measured by pulse oximetry (SpO2), and regional cerebral tissue oxygen saturation (SctO2) in patients undergoing laparoscopic robotic prostatectomy in steep head-down position. Thin lines indicate values in individual patients and thick lines indicate mean values (From: Kalmar AF, Foubert L, Hendrickx JFA, et al. Influence of steep Trendelenburg position and CO2 pneumoperitoneum on cardiovascular, cerebrovascular, and respiratory homeostasis during robotic prostatectomy. Br J Anaesth. 2012;104:433–439).

Figure 43.4. Changes in end-tidal CO2 values (PECO2), ventilatory plateau pressure (Pplat), tidal volume, and pulmonary compliance in patients undergoing laparoscopic robotic prostatectomy in steep head-down position. Thin lines indicate values in individual patients and thick lines indicate mean values (From: Kalmar AF, Foubert L, Hendrickx JFA, et al. Influence of steep Trendelenburg position and CO2 pneumoperitoneum on cardiovascular, cerebrovascular, and respiratory homeostasis during robotic prostatectomy. Br J Anaesth. 2012;104:433–439).

Regional Perfusion (Splanchnic, Renal, Cerebral, Intraocular)

Increased IAP, systemic CO2 absorption, and changes in patient position, along with hemodynamic changes (e.g., SVR and CI), influence splanchnic, renal, and cerebral blood flow during
minimal access surgery (Table 43-4). However, the clinical consequences of these changes depend largely on the patient’s pre-existing status.

Figure 43.5. Changes (mean and standard deviations) in mixed venous oxygen saturation (SvO2), heart rate (HR), and cardiac index (CI).

aHR significantly increased compared with horizontal, P <.05. (From: Lestar M, Gunnarsson L, Lagerstrand L, et al. Hemodynamic perturbations during robot-assisted laparoscopic radical prostatectomy in 45° Trendelenburg position. Anesth Analg. 2011;113:1069–1075).

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

    • Variable (decreased or no change) in bowel perfusion, mechanical pneumoperitoneum compression balanced by hypercarbic vasodilatation
    • Decreased hepatic blood flow

      • Beneficial during cryoablation of liver metastasis

    • Reduced renal perfusion and urine output (reduced during pneumoperitoneum/recovery following deflation)

  • Decreased femoral vein flow

    • Increased potential for deep vein thrombosis and pulmonary embolism

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 counterbalanced by the direct splanchnic vasodilatation caused by hypercapnia. Notwithstanding occasional reports of mesenteric ischemia following laparoscopy, the effects of pneumoperitoneum on the splanchnic circulation are not clinically significant.

The mechanical compressive and neuroendocrine effects of pneumoperitoneum may account for reduction in renal blood flow, glomerular filtration, and urine output (Table 43-5).29,30 However, the urine output generally normalizes following pneumoperitoneum deflation with no consequent renal dysfunction. Nevertheless, there may be clinical implications in critically ill patients and those with renal dysfunction undergoing extensive laparoscopic procedures requiring prolonged pneumoperitoneum.

An increase in PaCO2 during steep Trendelenburg positioning can increase cerebral blood flow and intracranial pressure with implications for patients with intracranial mass lesions. Therefore, maintenance of normocarbia is essential for preservation of cerebrovascular homeostasis.31 However, cerebral oxygenation and cerebral perfusion remain within safe limits during combined pneumoperitoneum and Trendelenburg position.27,32,33

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 intra-abdominal pressures

  • Intraoperative oliguria reversible within 2 h postoperatively
  • IAP <15 mm Hg safe even in patients with renal disease

Choroidal vasodilatation and an increase in intraocular pressure may occur during CO2 pneumoperitoneum and steep head-down position.33 Intraocular pressure increased significantly during robotic-assisted radical prostatectomy with steep head-down position.33 Multivariate analysis suggested that the predictors of IOP include duration of surgery and end-tidal CO2 (ETCO2).

Respiratory and Gas Exchange Effects

Changes in pulmonary function during laparoscopy include reduction in lung volume and pulmonary compliance secondary to cephalad displacement of the diaphragm caused by increased IAP and patient positioning14,15 (Table 43-6). Reduction in functional residual capacity (FRC) and total lung compliance results in basal atelectasis and increased airway pressure. In addition, the increase in minute ventilation required to avoid hypercarbia caused by systemic CO2 absorption further increases peak airway pressures. Although these changes are well tolerated by healthy patients, significant pulmonary dysfunction may occur in patients with pre-existing pulmonary disease (see the section on complications).

The CO2 insufflated into the peritoneal cavity is absorbed and causes hypercarbia. The absorption of gas from the peritoneal cavity depends on its diffusivity, the absorption area, and vascularity of insufflation site. Carbon dioxide absorption is greater during extraperitoneal (e.g., pelvic, hernia repair, and adrenorenal surgeries) insufflation than during intraperitoneal insufflation (e.g., cholecystectomy).34 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.35 However, it continues to increase progressively throughout extraperitoneal CO2 insufflation.

Although laparoscopic surgery is associated with increased CO2 absorption, the changes in arterial CO2 (PaCO2) concentrations remain clinically insignificant in healthy patients. However, in patients with severe pulmonary disease and limited elimination of CO2, the resulting rise in PaCO2 may be significant despite aggressive hyperventilation. In addition, in this patient population, the ETCO2 levels may underestimate arterial CO2 concentrations (PaCO2). Interestingly, the absorption and excretion of CO2 in morbidly obese patients appear to be similar to that of nonobese patients.20 However, in obese patients placed in the head-down position, arterial oxygenation and the alveolar–arterial oxygen gradient are impaired.21

Table 43-6. Pulmonary Changes During Laparoscopy

  • Diaphragm elevated
  • Decreased lung volumes (e.g., 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

A recent study found that pH decreased during laparotomy open procedures and laparoscopic procedures with CO2 pneumoperitoneum. However, reduced pH during the pneumoperitoneum was due to an increase in PaCO2 and promptly returned to a normal value after the desufflation of the abdomen. In contrast, reduction in pH after laparotomy was from metabolic factors and persisted for approximately an hour postoperatively.36

A recent animal study found that the improved arterial oxygenation and gas exchange after induction of pneumoperitoneum was due to improved ventilation–perfusion matching caused by redistribution of perfusion away from the collapsed lung regions. This was probably caused by enhanced hypoxic pulmonary vasoconstriction possibly mediated via increased arterial CO2.37

During robotic-assisted hysterectomy and prostatectomy performed under steep (40 degrees) head-down position, the changes in dead-space ventilation and venous admixture appear to be small.38 Another study in patients undergoing robotic prostatectomy also found minimal changes in respiratory parameters.27 However, the arterial end-tidal CO2 gradient increased after 120 minutes. Therefore, ETCO2 values may underestimate arterial CO2 levels, and maintaining ETCO2 between 25 and 35 mm Hg will result in PaCO2 levels of 35 to 45 mm Hg. Similarly, the institution of pneumoperitoneum (IAP of 12 mm Hg) and 45-degree head-down positioning resulted in decreased lung compliance by 40%.28 The ventilation–perfusion distribution did not differ significantly from baseline measurements, and oxygenation actually improved, probably due to optimization of intraoperative ventilation.28

Anesthetic Management

An optimal anesthetic technique would provide excellent intraoperative conditions while ensuring rapid recovery and low incidence of adverse effects as well as allowing early return to daily living activities.39,40 Local and regional anesthesia (spinal and epidural) can be used for shorter laparoscopic procedures, such as diagnostic laparoscopy, which requires lower IAP and minimal head-down tilt.40,41 Nevertheless, patient discomfort associated with creation of pneumoperitoneum and extreme position changes during the procedure can be significant. In addition, neuraxial anesthesia can cause significant sympathetic denervation, which may be associated with adverse ventilatory and circulatory responses, complicating perioperative management. Therefore, balanced general anesthesia with tracheal intubation and mechanical ventilation with acceptance of higher end-tidal carbon dioxide levels remains the best practice for minimally invasive surgical procedures.

Induction of Anesthesia and Airway Management

Because of its unique recovery profile, propofol is considered the sedative–hypnotic drug of choice for induction of anesthesia. Propofol also offers an advantage over other intravenous anesthetics because of its antiemetic properties and associated euphoria on emergence. Tracheal intubation and controlled mechanical ventilation comprise the accepted anesthetic technique to reduce the increase in PaCO2 and avoid ventilatory compromise from pneumoperitoneum and position changes. Although the laryngeal mask airway (LMA) has been used during short pelvic laparoscopic procedures, this evidence cannot be extrapolated to procedures requiring high IAP, steep head-down position, and upper abdominal laparoscopy as well as in patients at increased risk of regurgitation.42,43

Maintenance of Anesthesia

Maintenance of anesthesia with the newer inhaled anesthetics (i.e., desflurane or sevoflurane) remains the mainstay of modern anesthesia practice, probably because of the ease of titratability.39,44 In addition, inhaled anesthetics exert some neuromuscular blocking effect. Furthermore, inhalation anesthesia may provide faster emergence as compared to total intravenous anesthesia (TIVA) with propofol. However, propofol-based TIVA is associated with a lower risk of postoperative nausea and vomiting (PONV), but its cost and apparent complexity (i.e., need for infusion and difficulty in titration) deter some practitioners.44,45 Of note, except for patients with very high risk of PONV, the incidence of PONV with TIVA appears to be similar to that with inhalation anesthesia combined with prophylactic antiemetics.44

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Jul 5, 2016 | Posted by in ANESTHESIA | Comments Off on Anesthesia for Laparoscopic and Robotic Surgeries
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