Anesthesia for Robotic Surgery.you can run but you can't hide ...
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  • 1. Anesthesia for Robotic Surgery…you can run but youcan’t hide (it’s coming your way)Julie Ann Lowery, CRNA, MSUpon conclusion of the lecture, the learner/participant will be able to: 1. Have a basic understanding of robotic principles and mechanisms 2. Identify some of the surgical advantages of using the robot with laparoscopic procedures 3. Describe some of the anesthetic considerations for the patient having a robotic assisted laparoscopic surgical procedureRobotic surgery has transformed laparoscopic surgical procedures. More and more centersacross the United States are investing in robotic devices. While the initial cost may besubstantial, the end results and improved outcomes to the patient are worth the investment.Robotic devices offer the surgeon unprecedented control and precision of the surgicalinstruments employed during minimally invasive procedures. This results in lesspostoperative pain for the patient, shorter hospital stays, quicker recovery times, bettercosmetic effects, and physiologic function. Generally speaking, one may initially think of arobotic device in a sci-fi or futuristic reference, being autonomous and replacing the humansurgeon. This could not be farther from the truth. Robotics, while a sign of the times andthe future, require human intervention to operate. They help surgeons – not replace them. • a historical perspective Robots were initially designed by the National Aeronautics and Space Administration(NASA) for use in space travel. These robotic devices were employed in performing manualtasks aboard a spacecraft or out in space where a human could not go or, at least, movementwould be limited. Known as “slave devices”, these were controlled from a remote mastercontrol on Earth or from another spacecraft and were used extensively aboard the SpaceShuttle missions between 1983 and 1997. From that technology emerged “virtual reality”which allowed the interaction with three-dimensional virtual screens. Robotic engineeringand virtual reality were then coupled together to develop a dexterous telemanipulator for theanastomoses of nerves and vessels in hand surgery.
  • 2. The U.S. Department of Defense recognized the applications that robotics andvirtual reality could provide in treating wartime casualties on the battlefield. Through theapplication of virtual reality, a wounded soldier could “be brought” to a surgeon. Thisbecame known as “telepresence.” Via this concept, a surgeon located on board an aircraftcarrier could perform surgical interventions on a wounded soldier who remained in a remotelocation near the battlefield. As a result, the Department of Defense went on to fund muchresearch utilizing telemanipulation combined with telepresence for use in mobile surgicalunits. In order to incorporate this technology to its full potential, engineers realized thatthe distance between the patient and the surgeon had limitations. To ensure the bestaccuracy and dexterity of the robotic device, the transmission delay or lag time between thesurgeon’s maneuvers and the robot’s reception of the commands and implementationrequired specific design. Delays exceeding 200 milliseconds would compromise the surgicalaccuracy and precision. Subsequently, the utilization of high-bandwidth fiberopticunderground cable over long distances was found to be the best solution at that time,allowing for a latency time of 155 milliseconds. The first video-laparoscopic cholecystectomy was performed in 1987 in France. In1988, the innovation of laparoscopic surgery was introduced to the Society of AmericanGastrointestinal Endoscopic Surgeons. From that point on, the implementation oflaparoscopy exploded! The advantages were soon realized: less invasive with better patientoutcomes. On the flipside, this was virtually a new surgical realm to master. Surgeons losttheir three-dimensional vision and impaired touch sensation. Additionally, a surgeon had tolearn how to manipulate long instruments within the patient’s body that were not directlybeing viewed. While advancements were made in regards to the logistics and the surgicalinstruments of laparoscopy, a better technique was on the horizon. Hence, the incentive forrobotic development. The ultimate goal was to develop a master-slave manipulator device which wouldmimic the natural movements of a surgeon’s hand and wrist. Early designs contained 4degrees of freedom and by 1992, an instrument was developed that allowed for 6 degrees ofmovement. In 1999, Intuitive Surgical acquired the rights for the existing technology,utilizing this to develop robotic instruments with 6 degrees of freedom which have evolvedto what is being widely used today. • the da Vinci Robotic Surgical System Briefly, we’ll just highlight one of the most modern surgical robotic systemsapproved by the FDA – the da Vinci. This is a telemanipulator robot which means that it isunder constant control of the surgeon operator who sits in a remote console. It iscomprised of 3 components: a console, an optical three-dimensional vision tower, and asurgical cart. The surgical cart (the robotic component) consists of 3 arms that aremanipulated by the surgeon via “real time” computer assisted control. One arm holds theendoscopic camera and the other 2 hold surgical manipulators and instruments. The latteremploys 6 degrees of freedom plus grasp, equilibrating it to the articulation of the surgeon’shand and wrist. This is a very heavy piece of equipment and extreme care must be takenwith moving it. After the patient is positioned for the surgical procedure, the cart must berolled into the surgical area and is then locked into position. It is imperative that the
  • 3. patient’s position is not changed after the robotic side arm is “docked” to avoid injury topatient. The console allows for a three-dimensional image of the surgical field. Theendoscope transmits two separate optical and digital images to the console’s visual monitor.The surgeon is visualizing two separate monitors, each eye seeing through an independentcamera channel which creates a three-dimensional image of the surgical field. Within theconsole, there are 2 levers – “the masters”, which attach to the surgeon’s index fingers andthumbs. There are also 3 foot pedals which allow the surgeon to disengage the roboticmotions, adjust the endoscopic camera, and control the cauterization. Lastly, the opticaltower consists of computer equipment which coordinates the left and the right “eyes” of thesurgeon providing stereotactic vision. The computer also translates the movement of thesurgeon’s hands into a digital format that corresponds to the robot’s articulations. • Surgical applications Robotic technology has been successfully implemented in many surgical procedures,including gastrointestinal laparoscopic surgery, cardiac surgery, thoracic surgery,neurosurgery, urologic surgery, orthopedic procedures, and gynecologic procedures. I amthe most familiar with robotic assisted urologic and gynecologic procedures so that is what Iam going to specifically highlight. If robotics is being utilized in other types of surgicalprocedures listed above where you practice, I highly encourage you to learn about theanesthetic implications and volunteer to provide these patients anesthesia!Urologic surgery At the University of North Carolina at Chapel Hill, the urology surgeons areexcellent with the da Vinci. Some of the primary urologic surgical procedures that employthe da Vinci robot are: nephrectomy, pyeloplasty, cystectomy with ileal conduit, and radicalprostatectomy. The latter is probably the most frequent procedure which utilizes the daVinci robot. Prostate cancer is the leading form of cancer in males. It is the second highest causeof death in males in the US, killing more than 40,000 men annually. Early detection carriesthe best prognosis and allows patients to have more treatment options, including surgicalremoval of the prostate. In a nutshell, the goals surrounding a radical prostatectomy are:  Remove the prostate and cancer  Preserve urinary function  Preserve erectile function (via a nerve-sparing procedure or approach)  Analyze the prostate after surgery to assess the risk of recurrence of cancer As outlined above, performing a robotic assisted laparoscopic radical prostatectomyoffers the surgeon AND the patient many advantages. The da Vinci system allows thesurgeon to have enhanced magnification, a 3-dimensional view of the operative field, andpreserve the nerves responsible for erections. The patient benefits greatly as well:  Decreased blood loss  Shortened length of hospital stay  Decreased postoperative pain  Less scarring  Shorter urinary catheter time  Faster return to regular activities  Anticipation of improved potency and continence
  • 4. Gynecologic surgery Robotic assist is also being widely used in gynecologic procedures for various underlyingdisorders: fibroids, pelvic masses, abnormal bleeding, endometriosis, pelvic floor disorders,and precancerous/cancerous disease processes. Depending upon the problem, treatmentoptions may not necessarily include surgery. On the flipside, hysterectomy is the mostcommon surgical procedure performed in women and roughly numbers about 650,000 casesannually in the US. The primary reason is that it is the definitive solution for many types ofcommon gynecologic conditions. If surgery is indicated, minimally invasive surgical (MIS)procedures have numerous advantages which are quite similar to those outlined earlier:  Minimal blood loss  Preservation of fertility for fibroid removal/myomectomy  Reduction in hospital stay  Less postoperative pain  Absence of a midline abdominal incision  Quicker recovery time • Anesthetic considerations Several of the anesthetic implications specific to robotic procedures mimic those forany laparoscopic surgery. However, there are some considerations unique to theseprocedures that anesthesia providers need to appreciate and understand. Some of these aresurgeon preferences but nonetheless, have good rationale behind them as they lead tooptimal surgical conditions and in the long run, better outcomes for the patient. So, let’shighlight a few of the main considerations…Anesthetic technique and agents… No mystery or surprises here. For any of the robotic procedures mentioned abovespecific to urology and gynecology (my experience), these patients always receive a generalanesthetic. A regional block – i.e. epidural catheter placement, either for anesthesiasupplementation and/or postoperative analgesia is just not indicated or even necessary. So,for those of us who really enjoy (and prefer) doing general anesthesia, this makes us happy. Each of us has our favorite anesthetic drugs, inhaled anesthetics, and techniques thatwe like to employ. Not a problem. As with any patient having any surgical procedure, theselected anesthetics should be catered around the patient, the patient’s history, and theiraccompanying co-morbidities. I personally avoid the use of nitrous oxide with laparoscopic procedures for severalreasons. But especially with the gynecologic procedures, postoperative nausea and vomitinghas a higher incidence. So, why make a potentially bad problem worse? Additionally, highnarcotic loads are not generally required as postoperative pain is much less a problem.Placement of IVs and additional invasive lines… For robotic assisted laparoscopic procedures, the patient’s arms will be tuckedin/secured at the sides. Additionally, you will not be able to access the patient’s arms orcheck the patency of the IV or fiddle with the noninvasive blood pressure cuff once the
  • 5. robot is “docked” into position. There are several reasons for the latter. Not only is therobot a huge piece of equipment but it will be literally in the way of accessing the patient.Also, the entire area above the patient is considered sterile. So, here is the message – place anything in the patient (additional IVs, an arterialline) PRIOR to the robot being positioned and locked into place above the patient. It is agreat idea to place a second large bore peripheral IV after induction. The patient usuallywill have had a bowel prep, probably will be dehydrated, and the surgeons are working inclose proximity to large blood vessels. In the event you need to give volume and/or bloodproducts quickly, you can do so without trouble if a second large IV is in place. And use afluid warmer with the second IV set up. An anesthesia colleague once told me that he neverhad to dc an IV STAT. Makes sense…the second IV can always be removed easily whenthe patient reaches the PACU. Once again, you will not be able to crawl up under thedrapes and start a second IV very easily in an emergent situation. Just a word about an arterial line...placing one or not placing one should bedetermined by the patient and the patient’s presenting history. As with other clinicalscenarios and patients, often times we place an arterial line for “our convenience.” Becausethe patient’s arms are tucked, having an arterial line for the sampling of ABG’s, ahemoglobin level, or even a blood sugar can be invaluable. If the patient does not warrantan arterial line postoperatively, it is easy enough for the PACU nurse to remove it then. Lastly, make sure the IVs run well after the arms have been tucked in and the arterialline has an acceptable waveform.Positioning the patient… The patient is under general anesthesia, the needed lines are in place, and now thesurgeons are ready to go! It is very important that all personnel in the operating room takean active role in properly positioning ANY patient for the surgical procedure. However,with robotic assisted procedures, there are a few nuances. Also, a surgeon may have aparticular positioning technique or strategy which is fine as long as it’s safe for the patient.Since my primary experience is with urology and gynecology procedures, that is what I amgoing to discuss. For the most part, both require similar positioning of the patient.Robot assisted laparoscopic prostatectomy  Arms padded and tucked at sides and well secured.  We place a beanbag high on the OR table with the U shaped tops wrapping around the patient’s shoulders for stabilization. Blue foam donuts are also placed between the shoulder AC joints and bean bag for padding. Padded shoulder blocks are then placed behind the bean bag for extra stabilization to prevent the patient sliding in the cephalad direction when placed into steep Trendelenburg.  Towels are placed across the patients chest and then wide adhesive tape is crossed across the patient’s chest and shoulders in an X formation to secure the patient to the OR table.  Our surgeons use a special OR table which splits the legs for surgical positioning. This minimizes the risk of peroneal nerve injury.  Once all of that is done, a “testing” of the Trendelenburg position is performed to ascertain that the patient is secure on the OR table and does not slide down in the cephalad direction. This is very important as the patient will be in steep Trendelenburg for quite some time.
  • 6. Robot assisted pyeloplasty  Lateral position – kind of a tilt, with the operative site on the body (i.e. left or right) being up and the patient can remain relatively flat.  A beanbag is used to secure the patient.  Don’t forget the axillary roll.  Proper padding must be present between the arms and the legs, especially between bony prominences.  Ensure that the “up arm” is well secured so it does not fall and stretch any nerves.  Make sure the male genitalia are not getting squished between the bean bag and body.Robot assisted gynecologic procedures  Arms padded and tucked at sides and well secured.  While supine, padded shoulder blocks are placed superior to the AC joints and fit snug on the OR table.  The patient’s legs are placed into padded leg holders and gently bent at the knee.  Steep Trendelenburg is also required for this patient. Nerve injuries remain one of the most common adverse outcomes in surgical patientsand reported closed claims event. And while a patient may sustain a nerve injury even withthe most meticulous surgical positioning and precautions placed, most nerve injuries arepreventable. That means that we need to be knowledgeable about proper surgicalpositioning techniques, have the proper surgical padding and positioning equipment toutilize, and know the nerves which are at greatest risk for injury for this patient and for thisprocedure. The ulnar nerve is the most common nerve injured during surgical procedures andanesthesia. One reason for its vulnerability is its superficial lie to the skin surface. It also caneasily be trapped between the bony prominences surrounding it. Ulnar nerve injury isslightly less prevalent when the arms are tucked at the side. However, it remains importantto wrap gel pads or foam around the ulnar area. The hands and fingers also need to beproperly padded and secured. With gynecological surgery, the foot of the bed will belowered. Ensure the fingers are not wedged in-between the OR table and the moveable endof the table foot piece. If they are, it is a great way to crunch fingers. Additionally, cut offthe clamps on the IV tubing that will be next to the patient’s skin. Also, place a 4x4 betweenany IV connections and/or stopcocks so that these do not place pressure or leave anindentation in the skin. Once the arms are secured, double check that the arms are reallysecured. With draping and positioning, it becomes more difficult to detect if the arms“slipped” and are now dangling along side of the OR table. When the legs are placed into padded leg holders, check that the legs are symmetrical –one should not be higher than the other. Also, excessive flexion and extension should beavoided as this can stretch the sciatic nerve. Ideally, the leg should be in a relaxed mid-position and both sides of the knees padded. The peroneal nerve runs lateral to the kneeand the sapphenous nerve runs medial to the knee. If there is excessive pressure to either ofthese areas, these nerves are at jeopardy for injury. If padded shoulder blocks are used (as mentioned above), astute and frequent checks forexcessive pressure over the AC joint are mandated, especially when the patient is placed into
  • 7. the steep Trendelenburg position. Excessive pressure on this part of the shoulder can causebrachial plexus injury. Keep in mind that when the blocks are placed superior to theshoulder while the patient is in the supine position, they may not feel “tight” above theshoulder. But when the patient’s head is lowered and gravity forces the body weightdownward, the latter force will be exerted against the shoulder blocks. Therefore, it isprudent to check the positioning of the blocks after they are put into place and make surethey fit very loosely around the shoulder – 2 fingers can easily be wedged between theshoulder and the block. This is somewhat of an insurance policy so that when the patientgoes head down, at least the blocks were not too tight to begin with.Positive pressure ventilation – the challenges and the solutions All of us have administered anesthesia for patients undergoing various laparoscopicprocedures and are aware of the potential pulmonary dynamic changes that occur secondaryto the CO2 insufflation. While this holds true for robotic assisted laparoscopy, it is worthmentioning a few words about the steep head-down position which is required. The combination of the positioning and CO2 insufflation can make ventilating thesepatients challenging. If the patient is obese, it becomes even more challenging. Utilizingpressure ventilation can nicely circumvent this problem and allow us to achieve adequatetidal volumes. Keep in mind that you need to be watchful of the peak aspiratory pressuresand not allow them to become excessive. The placement of an oral gastric tube is warranted.IV fluids…minimize! Because patients have been NPO and especially if they have undergone a bowelprep, we are inclined to want to give our patients a ton of IV fluids, especially at thebeginning of the case. When you are providing anesthesia for a robotic assisted urologic orgynecologic procedure, forget about that concept! The exception is for pyeloplasties. Our surgeons request that fluids intentionally be minimized before and during thesurgical procedure. The primary reason for this is that excessive IV fluids potentiate theformation of edema in the face and in the airway mucosa quite possible preventingextubation of the patient. When these cases were taking longer to perform, this was a veryreal encountered problem. In robotic prostatectomies, minimizing the IV fluids can alsokeep excessive urine out of the pelvis which could obscure the surgeons’ view while sewingthe anastomses. At the end of the case once the patient is flattened out, the surgeons thenapprove for us to give the patient IV fluids as needed. In robotic prostatectomies, oursurgeons actually ask us to start loading the patient with IV fluids at this time point.Preoperatively, I like to inform the patient and any family members that it is not unusual forthere to be visible swelling in the patient’s face and eyes postoperatively due to the steephead down position. While this will normalize within the first few hours after the procedureis complete, it may be a bit alarming to see and experience, especially if it were not discussedahead of time. One could possibly say that robotic assisted laparoscopic surgery is still in itsinfantile stages. With that stated, there is somewhat a lack of information in the literaturediscussing the specific anesthetic considerations for it. Therefore, consider this informationa starting point and build upon it as you are able. From all indicators, it appears that therobot in surgical procedures is here to stay. Good luck!
  • 8. ReferencesNishanian E, Mets B. Anesthesia for robotic surgery. In R. Miller (ed) Miller’s Anesthesia (6thed). Elsevier Churchill Livingstone. Philadelphia. 2005Many thanks to Les Meadowcroft, clinical sales rep with Intuitive Surgical, for his help andprovision of data and slides pertaining to the da Vinci system.Also I am very grateful to the advice and information from 2 of the best robotic surgeons Ihave the pleasure to work with at UNC: Dr. Eric Wallen (Urology) and Dr. John Boggess(GYN oncology).