Anesthesia for robotic surgery

Anesthesia for robotic surgery Presented by-Dr.Aditya Kumar KejriwalJR-3 Department of AnesthesiaROHILKHAND MEDICAL COLLEGE HOSPITALBAREILLY

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1. Robotic surgery is accomplished by an autonomous, reprogrammable manipulator designed to move and articulate specialized instruments through programmed motions that achieve a specific task. A robot can be given three-dimensional coordinates from any imaging device (e.g., computed tomography) that allows it to recognize surfaces on which it will do a specific, programmed task.

2. Robotically assisted surgery involves mechanical devices that move by a motorized system under partially programmed control, and that can be instantly controlled or modified by a surgeon's intervention. 2Introduction to Robotic Surgery

3. Computer-assisted surgery involves systems that are manually controlled by the surgeon, and that include a tracking system, sensors, and end-effector instruments. This system provides direct and continuous control of movements.

4.Telesurgery refers to the ability to perform surgery using computer-assisted instruments from a remote location.

5. Telemanipulation refers to the ability to produce electronically precise instrument movements at a distance from a remote location.3

6. Telepresence refers to virtual projection of images from remote sites. This virtual projection allows the surgeon to visualize intended robotic movements at distant locations. It also enables telementoring, which is supervision and instruction from a distant location.

7. Initially, robotically assisted surgical thoracic procedures increased the duration of required general anesthesia.

Concomitantly, the duration of one-lung ventilation has been taken to new time extremes, which has given us insight into the respiratory physiology of prolonged one-lung ventilation. 4

As surgeons gain expertise with robotically assisted surgery, operative times are expected to shorten dramatically to approach those for traditional open surgery.8. Because of the proximity of the side cart to the patient, the patient must be guarded against inadvertent contact from the motions of the robotic arms. Even more important, after the instruments are engaged to the arms of the robot and are inside the patient, the patient's body position cannot be modified unless the instruments are disengaged entirely and removed from the body cavity.

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Robotic surgery is the resulting transformation of the minimally invasive surgical evolution.

Robotic devices are being introduced to surgery because they allow unprecedented control and precision of surgical instruments in minimally invasive procedures.

The anticipated benefits of robotic or robot-assisted surgery to the patient include less pain and trauma, shorter hospital stays, quicker recovery, and a better cosmetic result.

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First-generation surgical robots are being installed in numerous operating rooms around the world. These are not true autonomous robots that perform surgical tasks; rather, they are mechanical helping hands that offer assistance in various fields of surgery. These machines still require human intervention to operate or to provide input instructions. Robotic devices are here to help surgeons, not to replace them.HistoryThe word robot was first used by Capek in his play Rossum's Universal Robots in 1921. It is derived from the Czech word robota, meaning forced labor.Robots were first developed by theNASA for use in space exploration.7

Figure 76-1 Degrees of freedom (DOF) in motion. A, Conventional laparoscopic instruments have only 4 DOF and grip. Insertion (i.e., movement in the z axis), roll, and movement along the x and y axis outside the body relative to a fulcrum point constitute the 4 DOF8

B, Depiction of the EndoWrist instrument with two added intracorporeal joints, producing 7 DOF.9

Engineers realized that the distance between patient and surgeon had an upper limit, beyond which accuracy and dexterity of instrument control would become degraded.

Latency is the time it takes to send an electric signal from a hand motion to actual visualization of the hand motion on a remote screen.

The lag time to send an electric signal to a geosynchronous satellite at 22,300 miles above the Earth and return is 1.2 seconds. 10

This transmission delay would prohibit practical surgery. Humans can compensate for delays of less than 200msec. Longer delays compromise surgical accuracy.

Tissue moves when force is applied to it, and with a visual delay greater than 200msec, the movement would not be noticed fast enough to avoid cutting in an unintended place.

The most optimistic attempt to provide telesurgical presence over long distances was undertaken using high-bandwidth fiberoptic ground cable. The latency time of 155msec allowed to perform a robot-assisted laparoscopic cholecystectomy between New York City and Strausbourg, France, in 2001.

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In 2003, a telerobotic surgical service was established between a teaching hospital in Canada, and a community hospital 250 miles away.

This service was designed to provide telerobotic assistance by an expert surgeon to a community-based surgeon. Some of the procedures performed include laparoscopic Nissen fundoplication, laparoscopic right hemicolectomy, laparoscopic sigmoid/anterior resection, and laparoscopic hernia repair.12

The robots are preprogrammed off-line, and tasks are invoked on command.

Robots used in orthopedic surgery and neurosurgery are examples.Precise tasks, such as drilling and probe insertion, are based on registration.

Registration is a mathematical process that allows location and anatomic orientation in three dimensions based on data derived from preoperative computed tomography (CT) or magnetic resonance imaging (MRI).

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A second type of robot is defined as an assist device, such as AESOP. These robots are used to control instrument location and guidance. Assist-device robots are not autonomous; they need input cues from the operator.

A third type of robot is a telemanipulator. These robots are under constant control of the operator. These devices mimic the operator's hand motions in an exact or scaled motion.

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Several telemanipulator robotic devices are available throughout the world.

The da Vinci Robotic Surgical System has been approved by the U.S. Food and Drug Administration (FDA) for laparoscopy, thoracoscopy, and intracardiac mitral valve repair surgery, and the ZEUS Surgical System has been developed in parallel and approved by the FDA for general and laparoscopic surgery

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Figure - The da Vinci Robotic Surgical System: Surgical console, patient cart with four mounted surgical arms, and an optical tower.16

The da Vinci system has three components: a console, an optical three-dimensional vision tower, and a surgical cart.

The surgical cart has four arms that can be manipulated by the surgeon through real-time computer-assisted control. The first two arms represent the surgeon's right and left arms, to hold the instruments, and the third arm positions the endoscope. 17

The optional fourth arm enables the surgeon to hold another instrument or perform additional tasks, such as holding countertraction and following running sutures, eliminating the need for a patient-side surgeon. The system allows the surgeon to be physically remote from the patient

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Figure -Operating room schematic of the use of a robotic surgical system in cardiac surgery.19

The system's instruments are designed to have 7 degrees of freedom, which enables it to approach the identical articulation of the human wrist . Seven degrees of freedom include three arm movements (in out, up down, side to side), and three wrist movementsyaw (side to side, left and right), pitch (up and down), and roll or rotational.

The seventh degree of freedom is grasping or cutting. The system design incorporates a frequency filter that eliminates hand tremor greater than 6Hz. Motion scaling also can be invoked up to a ratio of 5:1 (i.e., the surgeon moves 5cm, and the robot moves 1cm). Scaling allows for work on a miniature scale.

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The console also provides a three-dimensional image of the surgical field. The endoscope consists of dual, independent optical channels capable of transmitting digital images to the console's visual monitor..

At the console, the surgeon is actually looking at two separate monitors; each eye sees through an independent camera channel to create a virtual three-dimensional stereoscopic image.

The images are controlled through two independent light sources found on the optical three-dimensional vision tower21

Figure -The da Vinci Robotic Surgical System: Master controls that translate the surgeon's hand, wrist, and finger movement into real-time movements of surgical instruments inside the patient.22

The surgeon sits at the console and controls the telescope arm and three robotic manipulator arms. The viewing space provided is similar to a double-eyepiece microscope .

Each eyepiece displays a mirror reflection of a computer monitor screen. Each monitor displays one channel of the stereo endoscope to an eye, creating a virtual three-dimensional stereoscopic image of the surgical field.23

Figure -The da Vinci Robotic Surgical System: Stereo viewer that creates a virtual three-dimensional stereoscopic image.24

The surgeon controls the manipulators with two masters .

The masters are made of levers that attach to index fingers and thumbs of each hand. Wrist movements replicate the movements of the instruments at the end of the robotic arms.

The console has a foot pedal that disengages the robotic motions (i.e., clutching), another that allows adjustment of the endoscopic camera, and a third pedal for controlling the energy of electric cauterization.

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Figure -The EndoWrist instrument of the da Vinci Robotic Surgical System mimics the natural kinematics of the surgeon's hand and wrist. This design allows 7 degrees of freedom.

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The side cart of the robotic device has four arms that respond to the manipulative controls of the surgeon while sitting at the console. The cart is bulky and very heavy.

It has to be wheeled to the vicinity of the patient's surgical area and is locked into place.

Because of the proximity of the side cart to the patient, the patient must be guarded against inadvertent contact from the motions of the robotic arms. 27

Even more important, after the instruments are engaged to the arms of the robot and inside the patient, the patient's body position cannot be modified unless the instruments are disengaged entirely and removed from the body cavity.

Any patient movement from lack of muscle relaxant may be disastrous.

The clutching buttons allow for the robotic arms to be grossly positioned without moving the instruments within the trocars or access ports. A clutching function allows surgical assistants to exchange various instruments.

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The optical tower contains the computer equipment needed to integrate the left and right optical channels to provide stereoscopic vision and to run the software needed to control the kinematics of the robotic arms.

The computer interfaces the translated motion of the surgeon's hands to a digital code that moves mechanical levers, motors, and cables that allow the robot to articulate the exact motions of the surgeon's hand.

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The instruments in the body cavity must remain sterile, but interface with nonsterile robotic arms. Detachable disposable instruments facilitate this interface.

Each type of instrument requires different forces and motion scaling intrinsic to the task at hand and requires specific computer software processing. Additional operating room staff is required for detaching and exchanging task-specific instruments throughout the case.

Monitors are positioned on top of the tower so that all individuals in the operating room have a view of the surgical field.

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An obstacle that still needs research is tactile sensing. The feedback that the robot offers for the surgeon's applied force is inferior. The robot offers some sensation, but the applied force does not correlate well with the force applied to the tissues.

This correlation varies with the type of instrument and depends on the torque applied; the operator must rely on visual cues from tissue distortion to gauge how much pressure is being generated.

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General SurgeryProcedures most commonly performed include cholecystectomy, fundoplication, Heller myotomy, bariatric surgery, and colectomy.

Robotic surgery overcomes some of the disadvantages of conventional laparoscopic procedures with three-dimensional imaging, elimination of motion reversal, motion scaling, and filtering of resting tremors, while offering an ergonomically comfortable position. .

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Other reported apparent advantages of robotic laparoscopic surgery are a short learning curve,better quality of repair,and ease of operation in morbidly obese patients because stiff instruments help counteract abdominal wall torque.

Robotic laparoscopic surgery also is associated with high patient satisfaction33

Anesthetic ConsiderationsIn the operating room, the patient is monitored with an electrocardiogram, pulse oximetry, axillary temperature probe, and noninvasive blood pressure cuff.

Bilateral peripheral intravenous access is valuable because the left upper extremity is not immediately available during the surgery.

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A standard induction and airway control with a tracheal tube is appropriate. Anesthesia can be maintained with a volatile agent. Many anaesthetists choose to run a background infusion of remifentanil. Muscle relaxation usually with a continuous infusion of a non-depolarizing neuromuscular blocking agent is of paramount importance in avoiding any movements by the patient while the surgical instruments are within the abdominal cavity. The position of the tracheal tube should be checked regularly.An orogastric tube and a urinary bladder catheter are placed. Convective-air body warmers are applied whenever possible.

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With the patient in the supine position, the patient is prepared and draped, and the abdominal cavity is insufflated with carbon dioxide (CO2) to a pressure not to exceed 20mmHg.

The trocar for the camera is placed manually. The side cart robot is brought very close to the patient's head to engage the other trocars with visual guidance from the robotic camera. Because of the proximity of the side cart to the patient's head, there is limited access to the patient's airway and neck, and the head must be guarded against inadvertent collision with the robotic arms when moving.36

After the robot is engaged, the patient's body position cannot be changed. The surgical team should be capable of rapidly disengaging the robotic device if an airway or anesthesia emergency arises.

As with any laparoscopic procedure that requires a pneumoperitoneum pressurized with CO2, ventilator adjustments may be required to normalize the exhaled CO2.Some surgeons argue that the benefit of invasive arterial monitoring does not outweigh the risks.

This issue should be considered for each patient based on a risk/benefit analysis.37

1.Use Fio2= 1.0

2.Begin one-lung ventilation with pressure control ventilation, maintaining a plateau pressure of