Complications of Minimal Access Surgery

Complications of Minimal




Complications of Minimal

Access Surgery Prof. Dr. R. K. Mishra INTRODUCTION Initial development of “minimal access surgery” began in the animal laboratory and was later studied in selected academic centers. It was imported to the community hospitals only when its benefits and safety were established. The development of laparoscopic cholecystectomy was not designed to enhance the safety of the procedure, but rather to reduce the discomfort associated with the surgical incision. The fierce economical competition in medicine fueled by the managed care movement led to the rapid adoption of laparoscopic surgery among surgeons and gynecologist in community hospitals who were not formally trained in this technique and acquired their knowledge by subscribing to short courses. Low complication rates were reported by centers specializing in laparoscopic surgery, mostly in academic centers. These centers were able to reduce the complication rate to minimum by developing proficiency in this surgery. Regrettably, many inexperienced surgeons perform this technique within sufficient training and are responsible for the majority of complications seen during the performance of laparoscopic surgery. Physicians who performed <100 such procedures reported 14.7 complications per 1,000 patients. In contrast, experienced surgeon reported a complication rate of only 3.8 complications per 1,000 procedures. The Southern Surgeons Club Survey reported that the incidence of bile duct injury was 2.2% when the surgeon had previously performed <13 procedures. As surgeons gained experience, the incidence of bile duct injury dropped to 0.1% afterward. ANESTHETIC AND MEDICAL COMPLICATIONS IN LAPAROSCOPY Although all types of anesthesia involve some risk, major side effects and complications from anesthesia in laparoscopy are uncommon. Anesthetic complications include those that are more common in association with laparoscopic surgery as well as those that can occur in any procedure requiring general anesthetics. One-third of the deaths associated with minor laparoscopic procedures such as sterilization or diagnostic laparoscopy are secondary to complication of anesthesia. Among the potential complications of all general anesthetics are: ■ Hypoventilation ■ Esophageal intubation ■ Gastroesophageal reflux ■ Bronchospasm ■ Hypotension ■ Narcotic overdose ■ Cardiac arrhythmias ■ Cardiac arrest. Laparoscopy results in multiple postoperative benefits including fewer traumas, less pain, less pulmonary dysfunction, quicker recovery, and shorter hospital stay. These advantages are regularly emphasized and explained. With increasing success of laparoscopy, it is now proposed for many surgical procedures. Intraoperative cardiorespiratory changes occur during pneumoperitoneum and partial pressure of arterial carbon dioxide (PaCO 2) increases due to carbon dioxide (CO2) absorption from peritoneal cavity. Laparoscopy poses a number of inherent features that can enhance some of these risks. For example, the Trendelenburg position, in combination with the increased intraperitoneal pressure provided by pneumoperitoneum by CO2, exerts greater pressure on the diaphragm, potentiating hypoventilation, resulting hypercarbia, and metabolic acidosis. This position, combined with anesthetic agents that act as muscle relaxant opens the esophageal sphincter, facilitates regurgitation of gastric content, which, in turn, often leads to aspiration and its attendant complications of bronchospasm, pneumonitis, and pneumonia. Intraoperative aspiration pneumonia is very common in laparoscopy, but postoperative pneumonia is common after open surgery. Various parameters of cardiopulmonary function associated with CO2 insufflation include reduced partial pressure of arterial oxygen (PaO2), oxygen (O2) saturation, tidal volume and minute ventilation as well as an increased respiratory rate. The use of intraperitoneal CO 2 as a distension medium is associated with an increase in PaCO2

Complications of Minimal

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and a decrease in pH. Increased abdominal pressure and elevation of the diaphragm may be associated with basilar atelectasis, which can result into right-to-left shunt and a ventilation-perfusion mismatch. Although during laparoscopy, the patient’s anesthetic care is in the hands of the anesthesiologist, it is important for the laparoscopic surgeon to understand the prevention and management of anesthetic complications by proper knowledge of risk involved with pneumoperitoneum. Carbon Dioxide Embolism Several case reports and experimental data suggest that the first finding during a CO2 embolism may be a rapid increase in end-tidal CO2 (EtCO2) tension as some of the CO2 injected into the vascular system is excreted into the lungs. As more gas is injected, a vapor lock is formed in portions of the lungs. Areas of the lung are ventilated but not perfused (i.e., become dead space) and the end-tidal CO2 rapidly falls. In contrast, during an air embolism, the end-tidal CO2 tension falls immediately. Other findings of a massive CO2 embolism include a harsh, mill-wheel murmur, a marked decrease in blood pressure, and a decrease in hemoglobin-O2 saturation. In minimal access surgery, the use of CO2 was started just to minimize the risk of CO2 embolism. CO2 is the most widely used peritoneal distension medium. Part of the reason for this selection is the ready absorption of CO2 in blood. It is 20 times more absorbable than room air; consequently, the vast majority of frequent microemboli that do occur are absorbed, usually by the splanchnic vascular system quickly and without any incident. However, if large amounts of CO2 gain access to the central venous circulation, if there is peripheral vasoconstriction, or if the splanchnic blood flow is decreased by excessively high intraperitoneal pressure, severe cardiorespiratory compromise may result. The reported incidence of death due to CO2 embolism is not clearly and authentically mentioned in any of the published article but it is assumed to be 1:10,000. Diagnosis of Carbon Dioxide Embolism Carbon dioxide embolism is difficult to diagnose clinically. Among the presenting signs of CO2 embolus are sudden, otherwise unexplained hypotension, cardiac arrhythmia, cyanosis, and the development of the classical “mill-wheel” or “water-wheel” heart murmur. The end-tidal CO2 may increase and findings consistent with pulmonary edema may manifest. Accelerating pulmonary hypertension may also occur resulting in right-sided heart failure. Prevention of Carbon Dioxide Embolism Because gas embolism may occur as a result of direct intravascular injection via an insufflation needle, the surgeon should ensure that blood is not emanating from the needle prior to the initiation of insufflation. Gynecologic surgeons can uniformly reduce the risk of CO2 embolus by operating in an environment where the intraperitoneal pressure is maintained at <20 mm Hg. In most instances, excepting the initial placement of trocar in an insufflated peritoneum, the surgeon should be able to function comfortably with the intraperitoneal pressure between 8 and 12 mm Hg, maximum 15 mm Hg. Such pressures may also provide protection from many of the other adverse cardiopulmonary events. The risk of CO2 embolus is also reduced by the meticulous maintenance of hemostasis and avoiding open venous channels, which are the portal of entry for gas into the systemic circulation. Another option in high-risk patient is the use of “gasless” or “apneumic” laparoscopy, where extra- or intraperitoneal abdominal lifting mechanisms are used to create a working space for the laparoscopic surgeon. However, limitations of these devices have, to date, precluded their wide acceptance by most of the surgeons. The anesthesiologist should continuously monitor the patient’s skin colors, blood pressure, heart sounds, electrocardiogram, and end-tidal CO2, so that the signs of CO2 embolus are recognized early and can be managed. Management of Carbon Dioxide Embolism If a CO2 embolism should occur: ■ The patient should receive 100% O2 ■ Insufflation should be stopped and the abdomen decompressed ■ The patient should be placed with the right side elevated in the Trendelenburg position to avoid further entrapment of CO2 in the pulmonary vasculature ■ A central venous catheter, if placed rapidly, may allow aspiration of CO2 ■ Full inotropic support should be instituted. Cardiopulmonary bypass may be required to evacuate the gas lock and help remove the CO2. If CO2 embolus is suspected or diagnosed, the operating room team must act quickly. The surgeon must evacuate CO2 from the peritoneal cavity and should place the patient in the Durant or left lateral decubitus position, with the head below the level of the right atrium. A large bore central venous line should be immediately established to allow aspiration of gas from the heart. Because the findings are nonspecific, other causes of cardiovascular collapse should be considered. Periodically, gases other than CO2 are investigated for use for laparoscopy. Argon, air, helium, and nitrous oxide have all been used in an attempt to eliminate the problems associated with hypercarbia and peritoneal irritation seen with CO2. The lack of solubility of air, helium, and argon effectively prevents hypercarbia that occurs with insufflation with CO2, but increases the lethality many fold, if gas embolism occurs. Deaths from argon gas embolism, when the argon beam coagulator has been used during 565

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SECTION 6: Miscellaneous laparoscopy, suggest that this concern is real. Nitrous oxide has solubility similar to that of CO2, but unfortunately it can support combustion. Explosions, when electrocautery was used following insufflation with nitrous oxide, have occurred. An intra-abdominal fire, when nitrous oxide was intended to be used for insufflation, has also been reported. Cardiovascular Complications Laparoscopic surgery requires the insufflation of CO2 into the abdominal cavity. Complications associated with CO2 insufflation include: ■ Escape of CO2 into the heart or pleural cavity ■ Effects of the resultant increased intra-abdominal pressure on cardiac, renal, and liver physiology ■ Effects of the absorbed CO2 on cardiorespiratory function. The fatal complication of CO2 embolization to the heart and lung was discussed earlier. CO2 is insufflated under 12–15 mm Hg pressure to elevate the abdominal wall and allow the camera the necessary distance to the organ operated on. Depending on the intra-abdominal pressure used and the position the patient is placed—head up or head down—several potential harmful physiologic derangements may occur. Cardiac arrhythmias occur relatively frequently during the performance of laparoscopic surgery and are related to a number of factors, the most significant of which is hypercarbia and the resulting acidemia. Early reports of laparoscopy-associated arrhythmia were in association with spontaneous respiration. Consequently, most anesthesiologists have adopted the universal practice of mechanical ventilation during laparoscopic surgery. There are also a number of pharmacological considerations that lead the anesthesiologist to select agents that limit the risk of cardiac arrhythmia. The surgeon may aid in reducing the incidence of hypercarbia by operating with intraperitoneal pressures that are <15 mm Hg. The use of an alternate intraperitoneal gas is another method by which the risk of cardiac arrhythmia may be reduced. However, while nitrous oxide is associated with a decreased incidence of arrhythmia, it increases the severity of shoulder tip pain, and, more importantly, is insoluble in blood. External lifting systems (apneumic laparoscopy) are another option that can provide protection against cardiac arrhythmia. Hypotension can also occur secondary to excessively increased intraperitoneal pressure resulting in decreased venous return and resulting decreased cardiac output. This undesirable result may be potentiated, if the patient is volume depleted. Hypotension secondary to cardiac arrhythmias may also be a consequence of vagal discharge in response to increased intraperitoneal pressure. All of these side effects will be more dangerous for the patient with preexisting cardiovascular compromise. Gastric Reflux during Laparoscopy Patients undergoing laparoscopy are usually considered at high risk of acid aspiration syndrome due to gastric regurgitation, which might occur due to the rise in intragastric pressure consequent to the increased IAP. However, during pneumoperitoneum, the lower esophageal sphincter tone far exceeds the intragastric pressure and the raised barrier pressure limits the incidence of regurgitation. Many study aimed to evaluate whether or not the use of intermittent positive pressure ventilation via the laryngeal mask airway that is associated with a higher risk of gastroesophageal reflux when compared with intermittent positive pressure ventilation via a tracheal tube in patients undergoing day-case gynecological laparoscopy in the headdown position. Generally, gastric regurgitation and aspiration are complications potentiated by laparoscopic surgery. Some patients are at increased risk, including those with obesity, gastroparesis, hiatal hernia, or any type of gastric outlet obstruction. In such patients, it is important to quickly secure the airway with a cuffed endotracheal tube and to routinely decompress the stomach with a nasogastric or orogastric tube. The surgeon can contribute to aspiration prophylaxis by operating at the lowest necessary intraperitoneal pressure. Patients should be taken out of the Trendelenburg position prior to being extubated. The adverse effects of aspiration may be minimized with the routine preoperative administration of metoclopramide, H2 blockers, and nonparticulate antacids. Extraperitoneal Gas During laparoscopic surgery, a number of the complications associated with pneumoperitoneum or its achievement are described in the vascular, gastroenterologic, urologic, and anesthetic sections. However, the problem of extraperitoneal placement or extravasation of gas has not been considered. In some instances, this complication occurs as a result of deficient technique (incorrect placement of insufflation needles; excessive intraperitoneal pressure); while in others, the extravasation is related to gas tracking around the ports or along the dissection planes themselves. Subcutaneous emphysema may occur if the tip of the Veress needle does not penetrate the peritoneal cavity prior to insufflation of gas. The gas may accumulate in the subcutaneous tissue or between the fascia and the peritoneum. Extraperitoneal insufflation, which is associated with higher levels of CO2 absorption than intraperitoneal insufflation, is reflected by a sudden rise in the EtCO2, excessive changes in airway pressure, and respiratory acidosis. Subcutaneous emphysema most commonly results from preperitoneal placement of an insufflation needle or

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leakage of CO2 around the cannula sites, the latter frequently because of excessive intraperitoneal pressure. The condition is usually mild and limited to the abdominal wall. However, subcutaneous emphysema can become extensive, involving the extremities, the neck, and the mediastinum. Another relatively common location for emphysema is the omentum or mesentery, a circumstance that the surgeon may mistake for preperitoneal insufflation. Usually, the diagnosis will not be a surprise for the surgeon that will have had difficulty in positioning the primary cannula within the peritoneal cavity. Subcutaneous emphysema may be readily identified by the palpation of crepitus, usually in the abdominal wall. In some instances, it can extend along contiguous fascial planes to the neck, where it can be visualized directly. Such a finding may reflect the development of mediastinal emphysema. If mediastinal emphysema is severe or if pneumothorax is developing, the anesthesiologist may report difficulty in maintaining a normal pCO2, a feature that may indicate impending cardiovascular collapse. should result in creation of a low or negative intraperitoneal pressure (1–4 mm Hg). Insufflation should be initiated at a low flow rate of about 1 L/min until the surgeon has confidence that proper placement has been achieved. Loss of liver dullness should occur when about 500 mL of gas has entered the peritoneal cavity. The measured intraperitoneal pressure should be below 10 mm Hg but up to 14 mm Hg, if the patient is obese. Abdominal distension should be symmetrical. If, at any time, the surgeon feels that the needle is not located intraperitoneally, it should be withdrawn and reinserted. Once the peritoneal cavity has been insufflated with an adequate volume of gas, the primary trocar is introduced. The laparoscope is introduced, and, if the cannula is satisfactorily located, the tubing is attached to the appropriate port. The risk of subcutaneous emphysema may be reduced by maintaining a low intraperitoneal pressure following the placement of the desired cannulas operate below 15 mm Hg and usually work at about 10 mm Hg. Although primary blind insertion of sharp trocar has been demonstrated to be as safe as secondary insertion following pneumoinsufflation, the relative incidence of subcutaneous emphysema is unknown. Prevention Management The risk of subcutaneous emphysema during laparoscopic surgery is reduced by proper positioning of an insufflation needle. Prior to insertion, it is important to check the insufflation needle for proper function and patency and to establish the baseline flow pressure by attaching it to the insufflation apparatus. The best position for insertion is at the base of the umbilicus, where the abdominal wall is the thinnest. The angle of insertion varies from 45° to near 90°, depending upon the patient’s weight, the previous abdominal surgery, and type of anesthesia as described in the section on prevention of vascular injuries. The insertion action should be smooth and firm until the surgeon observing and listening to the device passing through the layers—two (fascia and peritoneum) in the umbilicus and three (two layers of fascia; one peritoneum) in the left upper quadrant feels that placement is intraperitoneal. No one test is absolutely reliable at predicting intraperitoneal placement. Instead, a number of tests should be used. Of course, aspiration of the insufflation needle should precede all other evaluations. Two tests depend upon the preinflation intraperitoneal pressure. If a drop of water is placed on the open end of the insufflation needle, it should be drawn into the low-pressure intraperitoneal environment of the peritoneal cavity. Although some disagree, the elevation of the anterior abdominal wall is a reasonable way of creating a negative intraperitoneal pressure. Perhaps, a more quantitative way of demonstrating the same principle is to attach the tubing to the needle after insertion but prior to initiating the flow of gas. Elevation of the abdominal wall Subcutaneous emphysema often presents a management dilemma. Rarely, subcutaneous emphysema has pathophysiologic consequences. More often, it is extremely uncomfortable for the patient and is often disfiguring and alarming for patients and family. When subcutaneous emphysema is severe, physicians may feel compelled to treat it, but the currently described techniques are often invasive or ineffective. If the surgeon finds that the insufflation has occurred extraperitoneally, there exists a number of management options. While removing the laparoscope and repeating the insufflation is possible, it may be made more difficult because of the new configuration of the anterior peritoneum. Open laparoscopy or the use of an alternate sites such as the left upper quadrant should be considered. One attractive approach is to leave the laparoscope in the expanded preperitoneal space while the insufflation needle is reinserted through the peritoneal membrane, caudal to the tip of the laparoscope under direct vision. For mild cases of subcutaneous emphysema, no specific intra- or postoperative therapy is required, as the findings, in at least mild cases, quickly resolve following evacuation of the pneumoperitoneum. When the extravasation extends to involve the neck, it is usually preferable to terminate the procedure, as pneumomediastinum, pneumothorax, hypercarbia, and cardiovascular collapse may result. Following the end of the procedure, it is prudent to obtain a chest X-ray. The patient should be managed expectantly unless a tension pneumothorax results, when immediate Diagnosis 567

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SECTION 6: Miscellaneous evacuation must be performed, using a chest tube or a wide bore needle (14–16 gauge) inserted in the second intercostal space in midclavicular line. ELECTROSURGICAL COMPLICATIONS Unlike open surgery where hemostasis (control of bleeding) is accomplished by pressure and careful application of fine clamps and ligatures, laparoscopic surgery must rely on electrosurgery to achieve hemostasis. Excessive use of energy can burn a hole in the wall of the organ involved. Current can also cause injury to adjacent organs and even distant organs. Complications of electrosurgery occur secondary to thermal injury from one of three basic causes. The first is thermal trauma from unintended or inappropriate use of the active electrode(s). The second from current diverting to another, undesirable path, causing injury remote from the immediate operative field. Third is injury at the site of the “return” or dispersive electrode. Active electrode injury can occur with either unipolar or bipolar instruments, while trauma secondary to current diversion or dispersive electrode accidents only occur with the unipolar technique. Complications of electrosurgery are reduced with strict adherence to safety protocols coupled with a sound understanding of the circumstances that can lead to undesirable effects on tissue. Active Electrode Trauma Unintended activation in open space without touching the tissue is one of the more common mechanisms by which the active electrode causes complications. Such a complication frequently occurs when an electrode, left untended within the peritoneal cavity, is inadvertently activated by compression of the hand switch or depression of the foot pedal. Control of the electrosurgical unit (ESU) or generator by someone other than the operating surgeon is also a source of accidental activation of the electrode. Direct extension is another mechanism by which the active electrode(s) cause complications. The zone of vaporization or coagulation may extend to involve large blood vessels or vital structures such as the bladder, ureter, or bowel. Bipolar current reduces, but does not eliminate, the risk of thermal injury to adjacent tissue. Consequently, care must be taken to isolate blood vessels prior to desiccation, especially when near vital structures and to apply appropriate amounts of energy in a fashion that allows an adequate margin of noninjured tissue. Diagnosis During minimal access surgery, the diagnosis of direct thermal visceral injury may be suspected or confirmed intraoperatively. Careful evaluation of nearby intraperitoneal structures should be made if unintended activation of the electrode occurs. The visual appearance will depend upon a number of factors including the type of the electrode, its proximity to tissue, the output of the generator, and the duration of its activation. High power density activations will often result in vaporization injury and will be more easily recognized than lower power density lesions that result in desiccation and coagulation. The diagnosis of visceral thermal injury is often delayed until the signs and symptoms of fistula or peritonitis present. This will be particularly true with desiccation injury. Because these complications may not present until 2 to at least 10 days following surgery, long after discharge, both the patient and the physician must be made aware of the possible consequences. Consequently, patients should be advised to report any fever or increasing abdominal pain experienced postoperatively. Prevention Electrosurgical injuries are largely prevented if: (a) the surgeon is always in direct control of electrode activation and (b) all electrosurgical hand instruments are removed from the peritoneal cavity when not in use. When removed from the peritoneal cavity, the instruments should be detached from the electrosurgical generator or they should be stored in an insulated pouch near to the operative field. These measures prevent damage to the patient’s skin, if the foot pedal is accidentally depressed. Management Once diagnosed, thermal injury to bowel, bladder, or ureter, recognized at the time of laparoscopy, should immediately be managed appropriately, considering the potential extent of the zone of coagulative necrosis. The extent of thermal trauma will depend upon the characteristics of the energy transferred to tissue. An electrosurgical incision made with the focused energy from a pointed electrode will be associated with a minimal amount of surrounding thermal injury and may be repaired in a fashion identical to one created mechanically. However, with desiccation injury created as a result of prolonged contact with a relatively large caliber electrode, the thermal necrosis may extend centimeters from the point of contact. In such instances, wide excision or resection will be necessary. Remote Injury Remote injury due to current diversion can occur when an electrical current finds a direct path out of the patient’s body via grounded sites other than the dispersive electrode. Alternatively, the current can be diverted directly to other tissue before it reaches the tip of the active electrode. In either instance, if the power density becomes high enough, unintended and severe thermal injury can result.

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These injuries can only occur with ground-referenced ESUs because they lack an isolated circuit. In such generators, when the dispersive electrode becomes detached, unplugged, or otherwise ineffective, the current will seek any grounded conductor. If the conductor has a small surface area, the current or power density may become high enough to cause thermal injury. Examples include electrocardiograph patch electrodes or the conductive metal components of the operating table. Modem ESUs are designed and built with isolated circuits and impedance monitoring systems or active electrode monitoring system. Consequently, if any part of the circuit is broken, an alarm sounds, and/or the machine “shuts down” thereby preventing electrode activation. Since the , widespread introduction of such generators, the incidence of burns to alternate sites has become largely confined to cases involving the few remaining ground-referenced machines. Insulation Failure Failure in the insulation coating the shaft of a laparoscopic electrosurgical electrode can allow current diversion to adjacent tissue. The high power density resulting from such small points of contact fosters the creation of a significant injury. During laparoscopic surgery, bowel is frequently the tissue near to, or in contact with, the shaft of the electrode, making it the organ most susceptible to this type of electrosurgical injury. The fact that the whole shaft of the electrode is frequently not encompassed by the surgeon’s visual field at laparoscopy makes it possible that such an injury can occur unaware to the operator. Prevention of complication of insulation failure starts with the selection and care of electrosurgical hand instruments. Loose instrument bins should be replaced with containers designed to keep the instruments from damaging each other. The instruments should be examined prior to each case, searching for worn or obviously defective insulation. When found, the damaged instrument should be removed and repaired or replaced. Despite all efforts, unobserved breaks in insulation may rarely occur. While the use of disposable instruments is often claimed as a way of reducing the incidence of insulation failure, there is no guarantee that this is the case, as invisible defects may occur in the manufacturing process. Furthermore, the insulation on disposable electrodes is thinner and more susceptible to trauma. Consequently, when applying unipolar electrical energy, the shaft of the instrument should be kept free of vital structures and, if possible, totally visible in the operative field. Direct Coupling During minimal access surgery, direct coupling occurs when an activated electrode touches and energizes another metal conductor such as a laparoscope, cannula, or other instrument. If the conductor is near to, or in contact with, other tissue, a thermal injury can result. Such accidents often happen following unintentional activation of an electrode. Prevention of direct coupling is facilitated by removal of the electrodes when not in use and visually confirming that the electrode is not in inappropriate contact with other conductive instruments prior to activation. Capacitive Coupling Many capacitive coupling of diathermy current have been reported as causes of occult injury during surgical laparoscopy. Capacitance reflects the ability of a conductor to establish an electrical current in an unconnected but nearby circuit. An electrical field is established around the shaft of any activated laparoscopic unipolar electrode, a circumstance that makes the electrode a capacitor. This field is harmless if the circuit is completed via a dispersive, low power density pathway. If capacitive coupling occurs between the laparoscopic electrode and a metal cannula positioned in the abdominal wall, the current without any complication returns to the abdominal wall where it traverses to the dispersive electrode. However, if the metal cannula is anchored to the skin by a nonconductive plastic retaining sleeve or anchor (a hybrid system), the current will not return to the abdominal wall because the sleeve acts as an insulator. Instead, the capacitor will have to search elsewhere to complete the circuit. Consequently, bowel or any other nearby conductor can become the target of a relatively high power density discharge. The risk is greater with high voltage currents such as the coagulation output on an electrosurgical generator. This mechanism is also more likely to occur when a unipolar electrode is inserted through an operating laparoscope that, in turn, is passed through a plastic laparoscopic port. In this configuration, the plastic port acts as the insulator. If the electrode capacitively couples with the metal laparoscope, nearby bowel will be at risk for significant thermal injury. During minimal access surgery, prevention of capacitive coupling can largely be accomplished by avoiding the use of hybrid laparoscope cannula systems that contain a mixture of conductive and nonconductive elements. Instead, it is preferred that all plastic or all metal cannula systems be used. When and if operating laparoscopes are employed, all metal cannula systems should be the rule unless there is no intent to perform unipolar electrosurgical procedures through the operating channel. Risk of this injury is very much minimized if low voltage radiofrequency current (cutting) is used and when the high voltage outputs are avoided. Dispersive Electrode Burns The use of isolated circuit generators with return electrode monitors has all but eliminated dispersive electrode-related 569

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SECTION 6: Miscellaneous thermal injury. Return electrode monitoring (REM) is actually accomplished by measuring the impedance (sometimes called resistance) in the dispersive electrode, which should always be low because of the large surface area. To accomplish this, most return electrode monitors, actually, are divided into two electrodes, allowing the generator to compare the impedance from the two sides of the pad. If the overall impedance is high or if there is a significant difference between the two sides, as is the case with partial detachment, the active electrode cannot be activated. Without such devices, partial detachment of the patient pad could result in a thermal injury because reducing the surface area of the electrode raises the current density. It is important for the surgeon to establish what type of ESU is being used in each case. Absence of an REM system is a reason for increased scrutiny of the positioning of the dispersive electrode, both before the surgery begins, and as the operation progresses. Electrode Shields and Monitors A United States-based company (Electroscope Inc.) markets a system that helps to reduce further the chance of director capacitive coupling. A reusable shield is passed over the shaft of the laparoscopic electrode prior to its insertion into the peritoneal cavity. This shield protects against insulation failure and detects the presence of significant capacitance. Should an insulation break occur or when capacitance becomes threatening, the integrated monitoring system automatically shuts down the generator. The shield enlarges the effective diameter of the electrode by about 2 mm, making it necessary to use larger caliber laparoscopic ports. Despite perceptions to the contrary, electrosurgery has been rendered a safe modality for use in surgical procedures. However, safe and effective application of electrical energy requires an adequate understanding and implementation of basic principles as well as the availability of modern electrosurgical generators and appropriate education of medical and support staff. Care and prudence must be exercised when utilizing electricity within the peritoneal cavity. The zone of significant thermal injury usually extends beyond that of the visible injury, a feature that must be borne in mind when operating in close proximity to vital structures such as bowel bladder, ureter, and large and important blood vessels. It is equally important to impart the minimal amount of thermal injury (if any) necessary to accomplish the task at hand, even around nonvital structures, by using the ideal power output and the appropriate active electrodes. HEMORRHAGIC COMPLICATIONS Hemorrhagic complications may occur as a consequence of entry into the peritoneal cavity or as a result of trauma incurred to blood vessels encountered during the course of the procedure. Hemorrhage Associated with Access Technique Great Vessel Injury During access, the most dangerous hemorrhagic complications of entry are to the great vessels, including the aorta and vena cava as well as the common iliac vessels and their branches, the internal and external iliac arteries and veins. The incidence of major vascular injury is probably underreported, but has been estimated to range widely from 0.93 to 9 per 10,000 cases. The trauma most often occurs secondary to insertion of an insufflation needle, but may be created by the tip of the trocar. However, not uncommonly, the injury is associated with the insertion of ancillary laparoscopic ports into the lower quadrants. The vessels most frequently damaged are the aorta and the right common iliac artery, which branches from the aorta in the midline. The anatomically more posterior location of the vena cava and the iliac veins provides relative protection, but not immunity, from injury. While most of these injuries are small amenable to repair with suture, some have been larger, requiring ligation with or without the insertion of a vascular graft. Not surprisingly, death has been reported in a number of instances. Diagnosis: If great vessels are injured, most often the problem presents as profound hypotension with or without the appearance of a significant volume of blood within the peritoneal cavity. In some instances, the surgeon aspirates blood via the insufflation needle, prior to introduction of distension gas. Frequently, the bleeding may be contained in the retroperitoneal space, a feature that usually delays the diagnosis. Consequently, the development of hypovolemic shock in the recovery room may well be secondary to otherwise unrecognized laceration to a great vessel. To avoid the late recognition, it is important to evaluate the course of each great vessel prior to completing the procedure. Prevention: There are a number of ways by which the incidence of large vessel trauma can be minimized. Certainly, it is essential that the positioning of ancillary or secondary trocar in the lower quadrants be performed under direct vision. This is more difficult for the primary cannula. It has been suggested that the use of “open laparoscopy” for the initial port entirely avoids the issue of great vessel injury secondary to insufflation needles and trocars. However, open laparoscopy has its own potential drawbacks such as increased operating time, the need for larger incisions, and a greater chance of wound infection, all without eliminating the incidence of bowel injury at entry. The risk of large vessel injury should be reduced if careful attention is paid to access technique and equipment used. If used, both insufflation needles and the trocar should be kept sharp and surgeon should use same instrument each time. The safety sheath of the insufflation needle should be checked to ensure that both the spring and the sliding mechanism

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are functioning normally. Many disposable trocar-cannula systems are constructed with a safety mechanism that covers or retracts the trocar following passage through the fascia and peritoneum. However, there are currently no available data that demonstrate a reduction in the incidence of major vessel injury with the use of these devices. The application of appropriate technique is based upon a sound understanding of the normal anatomic relationships between the commonly used entry points and the great vessels. A “safety zone” exists inferior to the sacral promontory in the area bounded superiorly by the bifurcation of the aorta, posteriorly by the sacral curve, and laterally by the iliac vessels. Safe insertion of the insufflation needle mandates that the instrument be maintained in a midline, sagittal plane while the operator directs the tip between the iliac vessels, anterior to the sacrum but inferior to the bifurcation of the aorta and the proximal aspect of the vena cava. Such positioning requires elevation of the abdominal wall while angling the insufflation needle about 45º to horizontal. The tactile and visual feedback created when the needle passes through the fascial and peritoneal layers of the abdominal wall, if recognized and heeded, may prevent overaggressive insertion attempts. Such proprioceptive feedback is diminished with disposable needles as compared to the classic Veress model. Instead, the surgeon must listen to the “clicks” as the needle obturator retracts when it passes through the rectus fascia and the peritoneum. The needle should never be forced. It is critical to note that these anatomic relationships may vary with body type and with the orientation of the patient to the horizontal position. In women of normal weight and body habitus, in the horizontal recumbent position, the bifurcation of the aorta is located immediately beneath the umbilicus. However, in obese individuals, the umbilicus may be positioned up to 2 or more cm below bifurcation. Fortunately, this circumstance allows the insufflation needle to be directed in a more vertical position—those between 160 and 200 pounds between 45 and 90°, while those women over 200 pounds at nearly 90°. Women placed in a headdown position (Trendelenburg position) will shift their great vessel more superiorly and anteriorly in a fashion that may make them more vulnerable to an entry injury. Consequently, positioning of the insufflation needle, and at least the initial trocar and cannula, should be accomplished with the patient in a horizontal position. This approach additionally facilitates the evaluation of the upper abdomen, an exercise that is limited if the intraperitoneal content is shifted cephalad by the patient’s head-down position. The risk of great vessel injury is likely reduced by insufflating the peritoneal cavity to adequate pressure. An intraperitoneal pressure of 20 mm Hg, while not desirable for prolonged periods of time, can aid in separating the abdominal wall from the great vessels during the process of insertion of a sharp trocar. Management: If blood is withdrawn from the insufflation needle, it should be left in place while immediate preparations are made to obtain blood products and perform laparotomy. If the diagnosis of hemoperitoneum is made upon initial visualization of the peritoneal cavity, a grasping instrument may be used, if possible, to temporarily occlude the vessel. While it is unlikely that significant injury can predictably be repaired by laparoscopically directed technique, if temporary hemostasis can be obtained, and the laceration visualized, selected, localized lesions can be repaired, with suture, under laparoscopic guidance. Such an attempt should not be made by any other than experienced and technically adept surgeons. Even if such an instance exists, fine judgment should be used so as not to delay the institution of lifesaving, open surgical repair. Most surgeons should gain immediate entry into the peritoneal cavity and immediately compress the aorta and vena cava just below the level of the renal vessels, gaining at least temporary control of blood loss. At that juncture, the most appropriate course of action, including the need for vascular surgical consultation, will become more apparent. Abdominal Wall Vessels Most commonly injured abdominal wall vessels are the inferior epigastric and superior epigastric vessel. They are invariably damaged by the initial passage of an ancillary trocar or when a wider device is introduced later in the procedure. The problem may be recognized immediately by the observation of blood dripping along the cannula or out through the incision. However, it is not uncommon for the cannula itself to obstruct the bleeding until withdrawal at the end of the case. More sinister are injuries to the deep inferior epigastric vessels, branches of the external iliac artery and vein that also course cephalad, but are deep to the rectus fascia and often deep to the muscles themselves. More laterally located are the deep circumflex iliac vessels that are uncommonly encountered in laparoscopic surgery. Laceration of these vessels may cause profound blood loss, particularly when the trauma is unrecognized and causes extraperitoneal bleeding. Diagnosis: Diagnosis of abdominal wall vasculature injury is by visualization of the blood dripping down the cannula or by the postoperative appearance of shock, abdominal wall discoloration, and/or a hematoma located near to the incision. In some instances, the blood may track to a more distant site, presenting as a pararectal or vulvar mass. Delayed diagnosis may be prevented at the end of the procedure by laparoscopically evaluating each peritoneal incision following removal of the cannula. Prevention: With the help of telescope, transillumination of the abdominal wall from within will, at least in most thin 571

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SECTION 6: Miscellaneous women, allow for identification of the superficial inferior epigastric vessels. However, the deep inferior epigastric vessels cannot be identified by this mechanism because of their location deep to the rectus sheath. Consequently, prevention of deep inferior epigastric vessel injury requires that the surgeon understand the anatomic course of these vessels. The most consistent landmarks are the median umbilical ligaments (obliterated umbilical arteries) and the entry point of the round ligament into the inguinal canal. At the pubic crest, the deep inferior epigastric vessels begin their course cephalad between the medially located medial umbilical ligament and the laterally positioned exit point of the round ligament. The trocar should be inserted medial or lateral to the vessels, if they are visualized. If the vessels cannot be seen and it is necessary to position the trocar laterally, it should be positioned 3–4 cm lateral to the median umbilical ligament or lateral to the lateral margin of the rectus abdominis muscle. Too lateral an insertion will endanger the deep circumflex epigastric artery. The operator may further limit risk of injury by placing a No. 22 spinal needle through the skin at the desired location, directly observing the entry via the laparoscope. This not only provides more reassurance that a safe location has been identified, but the easily visualized peritoneal needle hole gives the surgeon a target for inserting the trocar with greater precision. A common mistake is to fashion the incision appropriately, only to direct the trocar medially in its course through the abdominal wall, thereby injuring the vessels. Another factor that may contribute to the risk of injury is the use of large diameter trocar. Consequently, for this and other reasons, the surgeon should use the smallest trocar necessary for performance of the procedure. Management: Superficial inferior epigastric artery lacerations usually respond to expectant management. Rotation of the cannula to a position where compression is possible is also helpful. Rarely is a suture necessary. We have found that the use of a straight suture passer is most useful for the ligation of lacerated deep inferior epigastric vessels. A number of other devices and techniques have been introduced that facilitate the accomplishment of this task. To summarize, the trocar and cannula are removed. Then, under laparoscopic visualization and using a ligature carrier, a ligature is placed through the incision and directed laterally and inferiorly, where it is held by a grasping forceps. The ligature carrier is removed and subsequently passed through the incision again, without a suture, but this time medial and inferior to the lacerated vessels. The suture is threaded into the carrier from within the peritoneal cavity and is then externalized and tied. For small incisions, narrower than the diameter of the surgeon’s finger, the knot may be tightened with a knot manipulator. There are other less uniformly successful methods for attaining hemostasis from a lacerated deep inferior epigastric vessel. The most obvious is the placement of large, throughand-through mattress sutures. These are usually removed about 48 hours later. Electrodesiccation may be successful. Either a unipolar or bipolar grasping forceps is passed through another ancillary cannula taking care to identify, grasp, and adequately desiccate the vessel. Either continuous or “blended” current is used at appropriate power outputs for the machine and the electrode. Another method that has enjoyed some success is temporary compression with the balloon of a Foley catheter, passed through the incision into the peritoneal cavity, then secured and tightened externally with a clamp. While some suggest that the balloon should be left in place for 24 hours, the delicate channel may be damaged by the clamp, making it impossible to deflate the balloon. For this reason, we not recommend this option. Intraperitoneal Vessel Injury The bleeding may result from inadvertent entry into a vessel failure of a specific occlusive technique or human error in the application of the selected technique. Furthermore, in addition to the problem of delayed hemorrhage inherent in transection of arteries, there may be further delay in diagnosis at laparoscopy because of the restricted visual field and the temporary occlusive pressure exerted by the CO2 within the peritoneal cavity. Diagnosis: During laparoscopy, inadvertent division of an artery or vein will usually become immediately self-evident. However, in some instances, transected arteries will go into spasm only to begin bleeding minutes to hours later, an event that may temporarily go unnoticed due to the limited field of view presented by the laparoscope. Consequently, at the end of the procedure, all areas of dissection should be carefully examined. In addition, the CO2 should be vented, decreasing the intraperitoneal pressure to about 5 mm Hg, allowing recognition of vessels occluded by the higher pressure. Prevention: Attention to meticulous technique is at least as important in laparoscopically-directed surgery as it is for open or vaginal cases. During dissection, vessels should be identified and occluded prior to division, a task made simpler by the magnification afforded by the laparoscope. If suture is used to occlude a vessel, it must be, of the appropriate caliber, positioned with an adequate pedicle and tied snugly with a secure knot. Electrosurgery, if used, should be applied in the appropriate waveform and power density and for a time adequate to allow for sufficient tissue desiccation. Clips should be of a size appropriate for the vessel and they must be applied in a secure fashion, also with an adequate pedicle of tissue. Care should be exercised to avoid manipulation of pedicles secured with clips or suture, as such trauma could

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