Safety during Electro surgery in Laparoscopy

Safety during electro surgery

The potential for accidental damage with electro surgery must always be borne in mind.

Overshoot

When tenting tissue and coagulating, control of the instrument may be lost for a moment as the tissue gives way and the momentum carries the tip of the hook to impinge and penetrate adjacent organs, vessels or structures. Thus always hook away from important structures.

To minimize this danger:

  1. monitor the force applied
  2. use the current to divide the tissue rather than attempt avulsion
  3. take small bites of tissue which are easily divided
  4. stabilise your arm by adducting it against your side.
  5. Work away from vulnerable structures.

Contact

Always remember to keep non-insulated parts of the instrument in view when applying current to avoid accidental contacts

Penetration

Remember that with a monopolar system the current may affect tissue below those on which you are working. Bowel is particularly susceptible to this kind of collateral damage from sparks and stray currents and discovery maybe delayed until the postoperative period with serious consequences.

Capacitance coupling

This now never arise but occurred in the early days of laparoscopic surgery with the use of plastic fixation screws to fix metal ports to the abdominal wall so as to prevent them from being accidentally pulled out when instruments were withdrawn during the course of an operation. The physics underling this injury is fairly straight forward. Whenever current is applied through an insulated instrument inserted through a metal trocar (port) some radiofrequency electric charge is transferred to the metal cannula with each activation (even if the insulation of the instrument is perfect). This effect is known as capacitance coupling. There is absolutely no problem if the metal cannula is in contact with the full Thickness of the abdominal wall, as the charge accumulates by the cannula is immediately discharged over a wide contact area (low power density, like the neutral return electrode plate) and hence no damage is done.

However, if the cannula is isolated from the abdominal wall, by a plastic screw (acting as an insulator), the cannula cannot discharge and thus accumulates a substantial charge with repeated activation of the electrosurgical instrument. Thus in essence it becomes an electric accumulator! Should at any stage the tip of the cannula inside the abdomen touch tissue or bowel, the accumulated charge will discharge immediately through at a single point of contact, i.e., with a high power density sufficient to causes an electrical burn. Since this occurs away from the site of action of the operation, it is usually overlooked. Capacitance coupling is not a problem if plastic fixation screws are not used and indeed they are banned nowadays.

Techniques to assist in control of bleeding

Methods of securing haemostasis

Endoscopic surgery is controlled almost entirely by vision. Any loss of view will result in loss of control and a reduction in safety. Haemorrhage, even to a minor extent, tends to obscure the operative field and consequently to be avoided. This means that vessels of a size that in open surgery could be divided without particular attention need to be secured prior to division when working endoscopically. Dissection must be more meticulous to proceed smoothly and you must develop a disciplined approach.

Magnification of tissues by the endoscope may initially confuse an inexperienced endoscopic surgeon as to the severity of the bleeding. A moderate bleed can appear torrential but an inexperienced endoscopic surgeon is well advised to convert should he have any doubt about his ability to control the situation quickly.

  • Pressure on the area applied by
  • Grasping adjacent tissue, and using this to overly and apply gentle pressure on to the area
  • Compression with pledget swab if the bleeding is not heavy until haemostasis is achieved by clipping or electro coagulation and the sucker
  • Suction / irrigation to identify the bleeding point prior to securing it.
  • Under-running by suture if the bleeding point cannot be identified.
  • Argon spray coagulation for raw bleeding areas
  • Occluding the vessel with graspers before clipping it
  • Application of I9brin and other glues or haemostatic agents

Avoid blind coagulation. Control the initial bleeding and then take your time to identify the bleeding point. In anatomically crowed areas containing important structures, it may be advisable to allow time for the bleeding to stop by compression for one or two minutes. If bleeding cannot be controlled inside 5 minutes, serious consideration should be given for conversion to open surgery. This period should be shorter if bleeding is heavy! Arterial.

Suction and Irrigation

The availability of suction and irrigation is as important for haemostasis in endoscopic surgery as gauze swabs are in open surgery. When bleeding does occur irrigation can assists in visualization of the bleeding point, and suction removes pooled blood and clears clots form the operative site. In addition the irrigation activates Hagemann factor and thus initiates spontaneous haemostasis.

We use heparinised Hartmann's solution (1000 units per 500 ml bag). This solution is preferred to normal saline because of its lesser conductivity, an important consideration when using monopolar HF electrocauttery. The heparin is added to reduce the stickiness of the instruments and thus improve handling especially of suture and ligature materials. It also aids removal of pooled blood. The bag of fluid is placed in a Fenwell pressure bag raised to 200mm Hg and hung from a drip stand. As the contents of the bag are used the pressure needs to be maintained. There are several pressurized irrigation systems available, some heat the irrigating fluid to body temperature, other provide pulse irrigation which is helpful from breaking up blood clots and cleaning the peritoneal gutters.

Suction and irrigation are also essential to deal with leakage from ultra abdominal organs e.g. bile leakage, bowel content, perforated ulcer, appendicitis. In these acute emergency situations, laparoscopic abdominal lavage of the peritoneal quadrants is aided by shaking the patient from side to side and changing the position of the operating table (head up, head down and sideways).

Clipping

Non-absorbable titanium clips may be used as ligature substitutes as in open surgery. The first clip appliers delivered a single clip and have to be withdrawn for reloading. Multiple fire clip applicators are available from disposable instrument manufactures. Also available are clips made of biodegradable materials such as polydioxanone (PDS).

The correct size of clip for the vessel must be selected. If used on important structures double clipping is recommended. The risk of slippage is high if the clip. The correct technique must be implemented and this will be demonstrated.

  • is too small for the vessel
  • does not project beyond the whole width of the vessel
  • is not applied at right angles to the vessel
  • is subjected to traction
  • includes fat or advential tissue around the vessel.

Coagulation

There are three available methods of coagulating blood vessels in endoscopic surgery. These are

  • Electrocoagulation (see electrosurgery)
  • Heater endocoagulation
  • High power ultrasonic coagulation
  • RF smart vessel sealing (LigaSure)
  • Photocoagulation.

Electrocoagulation using HF current may be monopolar, bipolar or quasi-bipolar. Bipolar is safer in dissections were space is restricted. When a monopolar system is used the safest form is soft coagulation. This setting maintains the voltage below 200 V so that sparks are not generated. Soft coagulation is recommended for endoscopic use. It may be applied by insulated graspers, hook, spatula or scissors. If a coaption technique is used it is important that both instruments are insulated to prevent current leaking to a cannula.

Endocoagulation is favoured by gynaecologists and is achieved with a sealed heater probe that is electronically controlled.

Photocoagulation is achieved by lasers in contact mode.

Pre-tied Loops

Pre-tied loops are available commercially. They are packaged with the following items, assembled ready for use

  1. push rod
  2. pre tied loop
  3. metal introducer tube

The pre tied loop has one long tail of suture material, which is threaded through the plastic push rod and encapsulated by the end. The region at the end of the push rod is designed to be broken so the thread may be pulled through the remainder of the rod. The push rod is passed through the metal introducer tube.

Clinical Uses

Preformed loops are used to ligate tissue e.g. the base of the appendix, lung bullae, and a hole in the gall bladder during Cholecystectomy. If multiple loops are required, the push rod and introducer can be reloaded with a length of ligature and additional loops fashioned by a surgeon with knowledge of external slip knots.

A pre-formed loop can also be used to secure a divided vessel after it has been isolated by a grasper. A slight modification of this technique allows it to be used to secure smaller identified vessels. One end is clipped and the other controlled temporally by a grasper, which has already been passed through a loop. The vessel is divided and the loop slid into place and tightened before the grasper releases the vessel.

Endoloops are also useful for sealing a perforated organ if this is to be removed, e.g. perforation of the gallbladder during laparoscopic cholecystectomy where closure is necessary to prevent escape of gallstones into the peritoneal cavity.

On no account must endoloops be used to close a perforation in any organ that is not going to be resected and removed, as the tissue included in the closed endoloop will slough off a few days later, because of ischaemia, resulting in peritonitis.

Procedure checklists

Veress needle insertion

  1. Check and set the insufflator : Pressure level and flow rate. Initial flow rates should be set at around 1 litre/mn. Optimal exposure is obtained with intra abdominal pressures of 12.0- 16.0mm Hg. Lower pressures (e.g. 10mm Hg) may give adequate visualisation, especially in women with lax abdominal walls. This causes less stretching of the diaphragm, possibly reducing postoperative pain. Low pressure pneumoperitoneum may be used in conjunction with techniques to lift the abdominal wall in patients with impaired respiratory or cardiac states. An initial setting of 10.0 - 15.0mm Hg is recommended for routine procedures.
  2. Connect gas supply to Veress needle.
  3. Check gas flow, needle patency and spring loaded central blunt stylet.
  4. Palpation test.
  5. Assessment of abdominal wall thickness by palpation with the fingers down to the aorta.
  6. Make a small skin incision.
  7. Tension abdominal wall and insert needle: The safest technique is to hold the needle at a point along its shaft at a distance from the tip which equates with that estimated by palpation as the abdominal wall thickness. The other hand holds up the abdominal wall, providing counter tension as the needle is threaded� in. You should be able to feel the needle puncture two distinct layers. Once the sharp tip enters the peritoneal cavity, the spring loaded blunt stylet is released with an audible (palpable) click.
  8. Check that the needle is in the correct position: A number of tests exist to confirm correct positioning of the needle tip.
    1. Aspiration: uses a saline filled syringe
    2. Saline drop test: uses a drop of saline in the Veress needle hub
    3. Negative pressure test: retraction of the anterior abdominal wall
    4. Early insufflation pressures
    5. Volume test: approx. 3 liters of gas are required to reach pressures of 10 mm Hg
    If an extra peritonea] position is suspected the needle can be withdrawn and repositioned. The number of passes required should be recorded. If a small amount of blood is aspirated, reinsertion is justified. II large amounts of blood escape up the needle, laparotomy is indicated. If bowel content is aspirated, the needle is withdrawn and reinserted in another location. Subsequent inspection and adequate treatment for bowel injury is mandatory.
  9. Insufflate :After a minimum of 1 litre of gas has been insufflated and needle position has been confirmed, the rate may be increased for more rapid filling. Periodic checks should be made of symmetric distension and abdominal resonance. Once the desired pressure has been reached, close the gas tap on the needle and withdraw it.

Laparoscopic troubleshooting

What would you do if the following situations occurred during a laparoscopic surgery?

(a) The field turns pink or yellow.

  1. White balancing may not have been done initially before inserting the telescope into the abdomen. White balance the camera should be done after withdrawing it.
  2. There may be wrongly connected RGB cable. The RGB cable should be checked for proper connection.
  3. Low voltage can sometimes alter the colour.
  4. Bile or blood spillage may turn the field pink or yellow due to staining of field. The inadvertent injury to bowel and spillage of bowel content may cause the field to tern yellow.

(b) Sudden black out.

  1. The cause of sudden black out may be due to fused bulb of light source. Switch of light source should be turn to use backup bulb.
  2. There may be disconnected camera or monitor cable. Or the fuse of camera blown due to fluctuation in voltage. The fuse and connection of camera and monitor should be checked.
  3. The tip of the telescope may be touching any object completely so there is no way for light to come out. The telescope should try to re-position.

(c) Poor definition of picture.

  1. The poor picture may be due to soiled lens with blood or other body fluids. It should be cleaned with warm water.
  2. The camera may not be white balanced or focused properly. The fine tuning of camera should be tried. The proper white balance of camera is necessary to get a good quality of picture. White balancing of camera should be done by placing the telescope 6 cm away from a complete white gauge piece or tissue paper.
  3. Excessive blood in the operative field resulting in absorption of light and poor field is one of the causes of poor vision of operating field. Proper irrigation and suction should be tried to get a clear view.

What action would you take to control marked intra abdominal bleeding from a trocar site?

(a) For immediate control.

  1. With inserted trocar pressure should be applied on the bleeding site either from outside or using a pledget from within under vision.
  2. A Foley's catheter can be inserted and the balloon can be inflated and pulled up creating a tamponade effect.
  3. A purse string suture can be taken around the incision of trocar and tightened to check the bleeding.
  4. A clamp can be applied to the port site till the bleeding is controlled

(b) For more permanent control.

  1. The bleeding vessel can be sutured from within under vision or controlled with diathermy, or a full thickness bite can be taken externally at the region of the bleeding vessel.
  2. The incision can be extended and the vessel can be found by proper debridement and then bleeding vessel should be ligated.

What action would you take if trocar injury to a large vessel occurs?

  1. The trocar should be left in place. The adequate resuscitative measures should be taken like blood should be at hand for the transfusion.
  2. Urgent laparotomy should be performed and repair of the vessel with adequate exposure should be done.
  3. The help of a vascular surgeon should be asked.

What would you do following a sudden collapse of the patient during an endoscopic procedure? Mention three possible causes for the collapse.

Possible causes for the collapse could be:

  1. Vaso-vagal shock due to peritoneal irritation
  2. CO2 embolism either by direct entry of gas into vessel or through absorption.
  3. Hypercarbia due to systemic CO2 absorption results in respiratory acidosis, pulmonary hypertension leading to cardiac dysrhythmia:
  4. Arrhythmias AV dissociation, junctional rhythm, sinus bradycardia and asystole due to vagal response to peritoneal stretching.

Insufflation should be stopped and abdomen should be deflated, the patient should be kept in a head down and right up (steep left lateral Trendelenberg position) and 100% O2 should be administered. The blood gas levels should be analysed and corrected accordingly. The gas in the right ventricle should be removed with a central venous catheter if possible. If there is any arrhythmia, Atropine and anti arrhythmic should be given. In case of ventricular fibrillation there may be need of DC defibrillator.

What pressure setting on the Insufflator would you select at the start of a diagnostic laparoscopy in an adult healthy patient?

If general anaesthesia is employed the starting flow rate is set at 1/L, pressure 12 mmHg and volume- 2L.

During diagnostic laparoscopy under local anaesthesia insufflation is begun at a flow rate of 1L/min. Initial low pressure- 2-3mmHg and volume not exceeding 2L.

(6).What would you do when?

(a) High pressure is registered when CO2 is insufflated in the VN before the needle has been placed in the body.

  1. Verres needle may be blocked or
  2. The gas tap may not be opened or the
  3. Gas tube may be kinked.

The tap should be checked for right direction and the needle should be flushed with saline to ensure that it is not blocked. The faulty veress needle should be changed.

(b) High pressures (10 or 15 mm Hg) are obtained during insufflation at 1L/min.

  1. The needle may be in the wrong plane and not in the peritoneal cavity.
  2. Gas tap or needle may be partially blocked

Right plane of insertion of needle should be checked by the saline drop test and negative aspiration test. If the problem continues than needle should withdrawn and re-inserted.

What would you do if after insufflation and on insertion of the telescope;

(a) You saw gas in the greater omentum?

If there is gas in the grater omentum the probability is that either the Verres needle or the trocar has entered and insufflated gas into it. There is an increased risk of systemic absorption of CO2 resulting in embolism. The necessary precautions to prevent this should be taken. Anti thrombotics (Egs.Heparin) should be given, the patient should be tilted head down and left lateral and 100% O2 should be given for inspiration.

(b) Only fat is seen and there is no crepitance in the abdominal wall.

The telescope is probably in the omentum and should be withdrawn and any possible injury of the omental vessel should be checked.

What action would you take when?

(a) You are unable to advance trocar into abdomen.

If the trocar is a disposable one confirm whether the blade tip is charged and re- introduce. Alternatively the tip may get discharged half way. The trocar should be removed recharged and inserted again. If it is a reusable trocar the tip may be blunt in which case it would be better to use a different sharp trocar.

(b) The tip of the obturator is seen entering the abdominal cavity during insertion of a secondary trocar.

The skin incision may be small so the trocar has to be removed, the incision should be extended and the trocar should be re- inserted.

List the safety mechanisms of different types of trocars?

a. Blunt (Hasson) trocar- blunt with insertion under direct vision. This type of trocar works on the safety of direct vision.

  1. Some disposable trocar have a sharp blade with a spring loaded safety shield which cover the blade tip once the peritoneal cavity is entered. This spring loaded spring mechanism reduces the risk of injury to the underlying viscera by the blade tip.
  2. Other disposable trocars require charging before insertion and when the tip enters the peritoneal cavity the blade tip retracts inside.
  3. Reusable trocars have triangular and conical tips. The triangular tips are sharper and tend to cause more vascular injury, the adequate force and fine hand movement is required for its safe use.
  4. Some disposable trocars have a screw shaped cannula, which has to be inserted like a screw, which enables the surgeon to have more control over the force with which he inserts the trocar. These have an additional advantage of not slipping out during the procedure.
  5. Non bladed obturators are used in some trocars for careful insertion where the problem of charging the blade tip and its patency does not arise.
  6. Visiport is a mechanism in which the telescope is inserted into the cannula and the gun is fired through the abdominal wall visualising each layer until the peritoneal cavity is reached. The trocars are thus inserted under vision layer by layer.
  7. Radially dilating trocars are also available. It has the advantage of entry through a very small incision and then incision can be dilated with the serial dilator.
  8. Ultrasonically activated trocar system is used in some high risk patients. It consists of an ultrasonic generator and a transducer attached to the trocar spike. The sharp pyramidal tip is activated with a frequency of 23.5 KHz and amplitude of 150 Micro m. The trocar fits a 5 mm plastic sheath that is introduced inside a 10mm dilator whose tip is conical.

List the factors that contribute to increase the risk of complications with using Verres needle.

- Faulty needle dysfunctional spring tip.

- Wrong method of insertion.

- Not guarding the needle and not inserting like a dart.

- Uncontrolled forceful insertion of needle.

- Wrong angle of insertion i.e. directing straight down instead of towards the pelvic cavity.

- Excessive force from shoulder rather than wrist while inserting.

- Previous abdominal surgery and scarred abdomen.

- Thin scaphoid individual: risk of deep entry.

- Spinal deformities kypho-scoliosis.

- Late pregnancy.

- Morbid obesity.

- Organomegaly.

- Portal hypertension

Complications of Minimal Access Surgery

INTRODUCTION

Minimal Access Surgery is technically demanding technique. As operative laparoscopy becomes more widely accepted, new techniques are being developed and more surgeons are adopting this form of management, the complication rate can be expected to rise. The incidence of laparoscopic complications is 1.1% to 5.2% in minor procedures and 2.5% to 6% in major ones (Kane & Krejs, 1984). It is becoming increasingly evident that, in order to reduce the prevalence of complications, training programmes must include supervision at all levels of development and there must be a high degree of awareness of the potential risks of laparoscopic surgery.

Complications can occur with any form of surgery The prevalence is difficult to assess because there have been no national surveys since those carried out by the American Association of Gynecologic Laparoscopists in 1976 and the Royal College of Obstetricians and Gynaecologists in 1977. At that time laparoscopy was virtually confined to diagnostic procedures and sterilisation. Only occasional other minor operative procedures were performed. A very few centres had begun to treat ectopic pregnancies, divide adhesions and perform salpingostomy.

Complications may be associated with:

  1. The anaesthetic
  2. The induction of pneumoperitoneum
  3. Insertion of primary and secondary trocars
  4. Thermal Instruments
  5. Mechanical Instruments
  6. Other associated conditions

1. THE ANAESTHETIC

Complications directly attributable to the general anaesthetic are no different from those which may occur when any other type of surgery is performed. Some features of laparoscopic surgery predispose to specific anaesthetic complications.

The use of a steep Trendelenburg position and the distension of the abdomen may both reduce excursion of the diaphragm. Carbon dioxide (CO2) can be absorbed particularly during prolonged operations. Monitoring by pulse oximetry, the use of endotracheal intubation and positive pressure assisted ventilation reduce the risk of hypercarbia to a minimum. If arrhythmia occurs the anaesthetist will be responsible for its management and is at liberty to instruct the surgeon to return the patient to the supine position, evacuate the pneumoperitoneum and discontinue the surgery.

Vasovagal reflex may produce shock and collapse especially if the anaesthetic is not deep enough. Again it may be prevented by efficient anaesthesia and should only be diagnosed when other causes of shock have been excluded.

Local anaesthesia may be used for tubal sterilisation and some other minor procedures. This may produce specific problems and complications:

1. Anxiety.

Anxiety may be prevented by administration of Diazepam 20 mg orally about one hour pre-operatively.

2. Vasovagal reaction.

This may be associated with bradycardia and, in more severe cases, cardiac arrest, convulsion and shock. The treatment should include:

  • Atropine 0.5 mg given intravenously (IV)
  • Oxygen given by endotracheal tube at a rate of 4-6 litres/minute
  • Adrenaline 0.5-1.0 ml of 1:100,000 solution given slowly IV
  • Respiratory and cardiac resuscitation.

3. Pain.

Pain may be prevented to some extent by the administration of non-steroidal anti-inflammatory drugs such as mefanimic acid, naprosene or fentanyl. It is prudent to have an anaesthetist available because about 2% of patients find the operation painful and consideration must be given to completing it under general anaesthesia (Gordon, 1984).

4. Allergic reactions and anaphylaxis.

Any local anaesthetic should be given initially as a small test dose to determine if an unsuspected hypersensitivity exists. Obviously if it does, no more medication should be administered. If a reaction occurs it will be characterised by agitation, flushing, palpitations, bronchospasm, pruritus and urticaria. The treatment will depend on the severity of the reaction and may include:

  • Adrenaline 0.5 mg (1:100,000 solution IVI or IMI)
  • Prednisolone 25 mg IVI
  • Theophylline 250 mg (10ml) given slowly IVI
  • Intravenous fluids
  • Oxygen

INDUCTION OF PNEUMOPERITONEUM

1. Extra-peritoneal gas insufflation

Failure to introduce the Veress' needle into the peritoneal cavity may produce extra-peritoneal emphysema. This occurs in about 2 per cent of cases. The diagnosis is made by palpation of crepitus caused by bubbles of CÓ2 under the skin.. If this is recognised early, the gas may be allowed to escape and the needle re-introduced through the same or another site.

If the complication is not recognised during the introduction of gas, the typical appearance of extra-peritoneal gas may be recognised when an attempt is made to introduce the telescope. It is always essential to view through the telescope during its insertion through its cannula. The typical spider-web appearance caused by pre-peritoneal insufflation will be seen when the telescope reaches the end of the cannula and further stripping of the peritoneum by the tip of the telescope avoided. The laparoscope should be withdrawn and attempts made to express the gas. The needle may then be re-introduced through the same or another site. Alternatively the trocar and cannula may be introduced by 'open laparoscopy'.

2. Mediastinal emphysema

Gas may extend from a correctly induced pneumoperitoneum into the mediastinum and create mediastinal emphysema. Extensive emphysema may cause cardiac embarrassment which will be diagnosed by the anaesthetist. There will be loss of dullness to percussion over the precordium. The laparoscopy must be abandoned and as much gas as possible evacuated. The patient must be kept under close observation until the gas has been absorbed.

3. Pneumothorax

Pneumothorax may result from insertion of the Veress' needle into the pleural cavity. Whenever a high site of insertion is chosen the needle should be directed away from the diaphragm and, as always, the standard protocol of aspiration and sounding tests employed.

Pneumothorax should be suspected if there is difficulty in ventilating the patient. There may be a contra-lateral mediastinal shift and increased tympanism over the affected area. The procedure should be abandoned and the gas allowed to escape. The patient should be kept under observation. Occasionally assisted ventilation and insertion of a pleural tube may be required.

4. Pneumo-omentum

The omentum is penetrated by the Veress' needle in about 2 per cent of cases. The misplacement should be recognised by the aspiration test and the position of the tip altered to free the needle. There will also be a raised insufflation pressure which should lead the surgeon to suspect an error in the position of the needle. The condition is usually innocuous unless and omental blood vessel is punctured.

5. Injury to gastro-intestinal tract

Certain conditions may predispose to injury by the Veress' needle. These include distension of the gastro-intestinal tract or adhesions of bowel to the abdominal wall.

Penetration of the stomach may occur when an abdominal site of insertion is chosen or the stomach is distended during induction of anaesthesia. Gastric distension may also occur if anaesthesia is maintained with a mask and should be suspected if there is upper abdominal distension or increased tympanism. In this case the stomach should be aspirated with a naso-gastric tube. The diagnosis of gastric perforation by the Veress' needle may be made when the patient belches gas. The laparoscope should be introduced and the stomach inspected carefully. Provided the stomach wall has not been torn, no surgical treatment is necessary but a broad spectrum antibiotic should be given. If the stomach has been torn, surgical repair either by laparotomy or laparoscopy is mandatory.

Aspiration following initial insertion of the needle should permit early recognition of perforation of the bowel but it is not fool-proof. Bowel penetration should be suspected if there is asymmetric abdominal distension, belching, passing of flatus or a faecal odour. The induction of pneumoperitoneum should be stopped and the needle re-sited to introduce the pneumoperitoneum correctly. The gastro-intestinal tract should be examined carefully for perforation. It is important that both sides of the bowel be examined as the exit wound may be larger than the entry wound. Faecal soiling demands immediate laparotomy and repair of the bowel. It is important to ensure that there has not been a through-and-through injury of a loop of bowel which is adherent to the peritoneum at the site of insertion. A simple needle penetration requires no treatment but the patient should be kept under observation and given broad spectrum antibiotics.

6. Bladder injury

Routine catheterisation of the bladder and proper siting of the needle should prevent bladder penetration. If pneumaturia is noted the needle should be partially withdrawn and the creation of pneumoperitoneum continued. The bladder peritoneum should be carefully inspected to ensure that no significant injury has been caused. The treatment of a simple puncture is conservative with postoperative bladder drainage.

7. Blood vessel injury

The Veress' needle may penetrate omental or mesenteric vessels or any of the major abdominal or pelvic arteries or veins. Minor vascular injuries involving the omental or mesenteric vessels are difficult to prevent as it is impossible to ensure that the omentum is not close to the abdominal wall during blind insertion of the insufflating needle. Injury may be suspected if blood returns up the open needle or if free blood is seen in the peritoneal cavity after insertion of the laparoscope. If blood returns up the needle and the patient's condition is stable, the site of injury may be investigated laparoscopically. The needle should be left in place and a 5mm laparoscope introduced through a suprapubic cannula. Minimal bleeding may usually be controlled by bipolar coagulation or a laparoscopic suture. Laparotomy is not usually necessary except in the case of injury to the superior mesenteric artery. Such injury requires repair by a vascular surgeon (Bassil et al, 1993)..

Injury to the major vessels may be prevented by lifting the abdominal wall, angling the needle towards the pelvis once the initial thrust through the fascia has been made and by inserting only as much of the needle as necessary. Thin patients and children are at particular risk of this injury.

Withdrawal of blood on aspiration following insertion of the needle should allow early detection of blood vessel injury. If injury to a vessel such as the aorta, inferior vena cava or common iliac vessel is suspected, the needle should be left place to mark the site of the injury and laparotomy performed through a mid-line incision. There is usually a large haematoma which obscures the site of the injury. The aorta should be compressed with a clamp or hand until a vascular surgeon arrives to perform definitive surgery.

Dramatic collapse may result from penetration of a major vessel but the bleeding may not be immediately evident if it is retro-peritoneal. The loose areolar tissue anterior to the aorta can allow accumulation of a considerable amount of blood before frank intra-abdominal bleeding is seen. A thorough search must be made to determine the extent of vessel damage. This includes retraction of bowel to expose the aorta above the pelvic brim which is the most common site of perforation. Failure to do so may result in continued bleeding and formation of a large haematoma leading to a second episode of shock some hours later

8. Gas embolism

Intravascular insufflation of gas may lead to gas embolism or even death. This can only happen if the penetration by the Veress' needle goes unrecognised and insufflation commences. It should be prevented by routine use of the aspiration test. The patient should be turned on to the left lateral position and, if immediate recovery does not take place, cardiac puncture performed to release the gas.

9. Puncture of liver or spleen

The liver or spleen may be punctured by the Veress' needle when a high insertion site is chosen. It may also occur in the presence of hepatomegaly or splenomegaly. The aspiration test and the high insufflation pressure will make it obvious that the needle is sited incorrectly in which case it should be withdrawn and re-sited.

10. Complications from the distension medium

Carbon dioxide (CO2) is the distension medium most commonly used for operative laparoscopy. Gas embolism is possible but uncommon because the gas is highly soluble and is reabsorbed so quickly that, even if there has been a moderate embolus, the circulatory changes return to normal within a few minutes and the patient recovers. Up to 400ml of gas may be intravasated without producing changes in the ECG.

Cardiac arrythmia may be due to excessive absorption of CO2. It is important to monitor the intra-abdominal pressure throughout the operation and to use an automatic pneumoflator for all but the simplest forms of surgery. This will cut out if the intra-abdominal pressure rises. Endotracheal intubation and positive pressure respiration will also help to prevent complications from CO2 insufflation.

Post-operative pain is common with CO2 insufflation due to peritoneal irritation which is a result of conversion of CO2 to carbonic acid. The chest pain may be confused with coronary heart disease and be treated inappropriately with anti-coagulants. This may produce a wound haematoma or intraperitoneal bleeding.

Nitrous oxide (N2O) has become popular with some laparoscopists because there are less side effects than with CO2. Anaesthetists can dispense with intubation and allow the patient to breath through a laryngeal mask. However, in modern laparoscopic practice, a diagnostic laparoscopy may develop into a complicated operative procedure. N2O supports combustion. Methane gas may be released into the peritoneal cavity following bowel injury. A high frequency monopolar current used during laparoscopic surgery may cause an explosion.

The main place for N2O is when laparoscopy is being performed under local anaesthesia in which case the pain factor becomes important. This is applicable to tubal sterilisation with clips, rings, or bipolar coagulation, but not to more advanced laparoscopic procedures.

INTRODUCTION OF TROCARS AND CANNULAE

Some of the most serious injuries that occur during laparoscopy are caused by the insertion of the trocars and cannulae. Insertion of the primary trocar and cannula is, of necessity, blind. The causation of injuries by the primary trocar are similar to those caused by the Veress' needle but the magnitude of the injury is greater.

The sites of the secondary portals of entry must be selected carefully and the insertion must always be made under visual control.

1. Injury to vessels in the abdominal wall

Superficial bleeding from the incision rarely gives rise to concern and always stops with application of pressure.

Bleeding from puncture of the deep inferior epigastric artery is more serious. The artery is at risk during the insertion of secondary trocars and cannulae. This may be prevented by transilluminating the abdominal wall before insertion in a thin patient or by visualising the artery laparoscopically as it runs lateral to the obliterated umbilical artery. The site of insertion can then be chosen by depressing the wall skin with the handle of the scalpel and noting its relationship to the vessels.

The diagnosis may be made by the sight of blood dripping into the pelvis from the trocar wound. Occasionally blood may actually be seen spurting across the abdominal cavity. Alternatively the immediate or delayed appearance of a large abdominal wall haematoma indicates injury to the deep inferior epigastric artery.

The treatment is usually simple. The trocar and cannula should be left in situ to act as a marker and also prevent the artery slipping away. A Foley catheter passed down the cannula and inflated may act as a compress and control the bleeding. Alternatively the incision should be enlarged to about 2 cm in length to expose the anterior rectus sheath. A round bodied needle should be inserted through the full thickness of the abdominal wall from the sheath to the peritoneum under laparoscopic control. The needle point should be brought out again to the surface of the rectus sheath and a knot tied firmly on the sheath. This is preferable to tying the knot on the skin which is painful and leaves an unsightly scar although it is acceptable to tie the knot over a gauze swab to prevent skin injury. It may be necessary to insert two sutures, one above and one below the site of bleeding.

Occasionally it may be necessary to open the wound wider to locate the bleeding artery. This should be reserved for those cases where there is profuse bleeding or primary laparoscopic suturing is ineffective.

2. Injury to an intra-abdominal vessel

Injury to minor blood vessels is usually self-limiting or can be controlled by bipolar electro-coagulation. Damage to major vessels is more serious than with a Verres' needle because of the size of the trocar tip and may result in profuse bleeding. Injury to omental vessels may compromise the vitality of a segment of bowel. Treatment of these injuries is by resuscitation, laparotomy, vascular repair or ligation and, where necessary, bowel resection and anastomosis with the assistance of the appropriate surgical colleague.

A small leak from the a major vein may not be immediately apparent. The intra-abdominal pressure of the pneumoperitoneum and the decreased venous pressure induced by the Trendelenburg position may temporarily control it. However, as soon as the intra-abdominal and venous pressures return to normal, the bleeding may recommence and produce a retro-peritoneal haematoma and shock.

It is essential therefore, at the completion of any laparoscopic procedure, but especially those involving the pelvic side wall, to inspect the course of the major vessels and look for a haematoma. This applies particularly to the treatment of endometriosis at this site. A small haematoma may be the only evidence of injury to a vein at the pelvic brim. Occasionally there may be a defect in the overlying peritoneum which indicates the site of entry of the trocar. It is essential to proceed to laparotomy to repair the vessel. A vascular surgeon should be consulted and the vessel compressed until the arrival of specialised assistance.

3. Injury to a hollow viscus

Injury to a hollow viscus may vary from superficial damage of the serosa to complete penetration into the lumen. If penetration has occurred the viscus may slip off the trocar, the trocar may remain within the lumen or, rarely, the trocar may pass right through the a loop of bowel which becomes impaled upon it. It is always important to inspect the bowel at the axis of insertion of the primary trocar and cannula to ensure that it has not been damaged. If the cannula remains within the bowel the injury will be obvious by the recognition of mucosal folds. A through and through injury may be missed and only become apparent by the sight of faecal soiling, a faecal smell when the pneumoperitoneum is released or the subsequent development of peritonitis.

Injury to the stomach or bowel are always serious. The management depends on the skill of the surgeon. The classical treatment is to perform laparotomy and suture the bowel in two layers. A skilled surgeon may perform the repair by laparoscopic suturing. The defect should be closed in two layers in such a way as to avoid stricture formation, there should be copious peritoneal irrigation and a drain should be inserted into the abdomen. Appropriate antibiotic therapy should be instituted.

It may not be possible to identify the site of injury by laparoscopy. In this case it is essential to perform laparotomy to find and treat the bowel injury. Failure to do this will result in the patient developing faecal peritonitis and becoming dangerously ill.

Bladder laceration may occur during mobilisation of the bladder in advanced pelvic surgery. It should be sutured in two layers using laparoscopic suturing technique and a Foley catheter inserted into the bladder.

4. Damage to other organs

Minor injuries to other organs are usually self-limiting. They should be inspected at the completion of the procedure. Peritoneal lavage must be carried out to remove blood and clot and ensure that the bleeding has stopped. A small puncture on the surface of the uterus may be treated with bipolar electro-coagulation if bleeding does not stop spontaneously.

Injuries to the liver and spleen are rare unless the organ is pathologically enlarged. Such injuries are more likely to occur in operations performed by general surgeons. Minor bleeding will stop spontaneously. Major haemorrhage requires immediate laparotomy.

THERMAL DAMAGE

Burns from electric current were one of the major causes of complications when monopolar tubal coagulation was the principle method of female sterilisation. The incidence of burns was dramatically reduced by the introduction of bipolar and thermal coagulation and mechanical devices to occlude the tubes.

Monopolar electric current passes into the patient's body from the electrode which may be forceps or a needle. The current passes into the patient's tissues at the point of contact and then must return to the generator via the return plate. This is usually placed on the patient's leg. The effect of the electric current will depend its power and the power density which, in turn depends on the area and duration of application. To obtain maximum tissue effect the area of application at the target organ is small. The current passes from that small area along the path of least resistance towards the return plate. In gynaecological surgery this pathway is usually over the surface of loops of bowel. The area of the return plate is large so the power density at its site of application to the skin is low. However on its return pathway the current may pass over a small area of contact between two organs. The power density at that point may be high. In this way a burn may occur outside the surgeon's visual field. Normally this does not happen and the current passes harmlessly to the dispersive plate.

Thermal injury to organs such as bowel may also result from leakage of current from the shaft of the instrument. This leakage may result from insufficient or faulty insulation or from capacitative coupling in which there is a build up of current in the shaft of the instrument because the normal escape route has been shut off. Current normally escapes from the metal cannula through the patient's anterior abdominal wall to the return plate. If a plastic cannula has been used this route is closed and the current may escape to bowel. If the contact point between instrument and bowel is small, the power density may be high and thermal injury will result.

Occasionally the monitoring system may not be properly earthed. If the current passes via an ECG electrode instead of to the return plate, the patient may suffer a skin burn because the ECG electrode is small and so the power density is high at this site. Alternatively, the current may pass along one of the ancillary instruments which, if not properly insulated, may produce a skin burn at the portal of entry or the surgeon may suffer a burn on the hands or face.

There is a danger of lateral heat spread with monopolar or bipolar current. It is important to ensure that no other organ is in contact with or near an organ to which electricity is being applied. Lateral spread may also be minimised by keeping the forceps blades close together. Build-up of thermal energy may be prevented by intermittent application of energy which, in effect, produces a pulsed current.

The bowel is the most commonly injured organ. The injury may range from minor blanching of the serosa to frank perforation. Perforation requires laparotomy, excision of the surrounding devitalised bowel and repair of the defect. If blanching is significant, laparotomy excision of the damaged tissue and surgical repair should be performed immediately. Failure to do so may result in delayed ischaemic necrosis at the site of the burn. Initially there may be few symptoms but commonly the patient will complain of feeling unwell and this feeling may not improve as quickly as usual. It should be realised that any patient who feels unwell on the day after surgery and whose condition does not improve over the next few hours, may have an unsuspected injury to the bowel. The unwary physician may allow the patient to return home. The insidious development of vague abdominal symptoms, discomfort, anorexia and possibly pyrexia may not be recognised by her medical attendants. A faecal fistula may not form for 48-72 hours. Fecal peritonitis slowly develops and the patient may become seriously ill over a period of days before re-admission is requested. Radiology followed by laparotomy reveals the desperate situation. Laparotomy is followed by repair of the bowel or, more often, colostomy and drainage of the peritoneum. A prolonged period of serious illness may follow.

It must always be remembered that electric current is potentially dangerous and all the safety rules for its use must be strictly obeyed.

INJURY FROM MECHANICAL INSTRUMENTS

The main injuries caused by scissors or forceps are to a blood vessels. Bleeding will be immediately obvious and should be controlled by bipolar or thermocoagulation or by suturing. Direct inadvertent injury to other organs by mechanical instruments may result from careless or clumsy use.

OTHER COMPLICATIONS

A number of other complications may result from laparoscopy.

1. Cervical laceration

It is common for the cervical tenaculum to cause a laceration of the anterior lip of cervix. The cervix should always be inspected at the end of the procedure. The bleeding may usually be controlled by pressure from sponge forceps but occasionally requires suturing.

2. Uterine perforation

Uterine perforation may be caused by the manipulating cannula or during dilatation and curettage. The perforation should always be inspected with the laparoscope during and at the end of the procedure. Bleeding is usually slight and the complication does not usually require treatment.

3. Shoulder pain

Carbon dioxide is converted to carbonic acid when it is in solution with body fluids. This is irritant to the peritoneum. Diaphragmatic peritoneal irritation produces pain which is referred to the shoulder by the phrenic nerve. This pain may be confused with cardiac pain by the unwary physician and treated inappropriately.

4. Pelvic inflammatory disease

There is a small risk of producing or exacerbating a pelvic infection by uterine cannulation and chromopertubation. Post-operative pelvic infection is probably less common after laparoscopic surgery than after laparotomy.

5. Omental and Richter's herniation

If the primary cannula is withdrawn with its valve closed, it is possible to draw a piece of omentum into the umbilical wound by the negative pressure so produced. This is usually recognised immediately and the omentum is easily replaced. Herniation may occur some hours after the operation. It is usually easy to replace it under local anaesthesia and resuture the wound.

Herniation does not occur commonly with 5mm skin incisions. Incisions greater than 7mm should be sutured in layers to prevent formation of a Richter's hernia.

6. Injuries from the operating table

Care must always be taken in positioning the patient on the operating table. Injury can be caused to the nerves of the leg and to the hip and sacro-iliac joints. Compression of the leg veins may predispose to venous thrombosis. The brachial plexus may be injured if the arm is abducted. The hands may be caught in moving parts of the table.

It is important that the patient touches no metallic parts of the table if electric energy is being used.

7. Foreign bodies

Occassionally tubal clips or rings or parts of instruments such as saphire laser tips may be inadvertently dropped and lost in the peritoneal cavity. They should be removed if they are easily found but there have been no reports of long term complications from such foreign bodies.

I shall protect them from all harm.� From the Hippocratic Oath, it is the mandate under which all physicians serve. It dictates that above all else, during the course of any medical intervention, no additional injury shall be inflicted upon one's patient. It is the very credo that governs every professional decision a doctor makes, however, in spite of all good intentions, and all professional expertise, there are times when a surgeon can unknowingly compromise patient safety.

Thermal burns to peripheral sites during electrosurgery are not uncommon, yet have long been an inherent risk of laparoendoscopic procedures. Incidences are on the rise, in fact, since more minimally invasive surgeries are performed now than ever before, but with conscientious management, such injury can be averted altogether. It is the role of all perioperative support personnel to ensure that, that which is preventable is indeed prevented, and in the case of electrosurgery, we no longer live in the dark ages.

In the past, all responsibility for monitoring the safety of electrosurgery instruments fell on the staff in Central Sterile Processing departments. Today's technological advances have effectively shifted that duty to the operating room, but, in spite of such progress, some facilities continue to let it remain in the Central Processing unit, a practice that should be highly discouraged.

The problem lies in the nature of endoscopy/ laparoscopy electrosurgical instruments themselves. Electrosurgery, both monopolar and bipolar, involves cutting tissue and controlling bleeding with electric current. Instruments used in laparoscopy and other electrosurgeries must be insulated to ensure that electricity is directed to the operating tip, and shielded from escaping along the instrument shaft. Insulation materials vary, but no matter the source, all of it is degradable. The reality is that an instrument with faulty insulation can conduct electricity through invisible lesions in the insulation, resulting in inadvertent damage to tissue or organs surrounding the targeted surgical site. Because the keyhole of minimally invasive surgery is so small, the surgeon cannot observe such phenomena outside his field of vision. The consequences can be catastrophic. Most injuries caused by insulation failure result in irreversible tissue death.

Accordingly, it is critical to patient safety that insulation be flawless to prevent escaping current. The AORN Board of Directors in its Recommended Practices for Electrosurgery� advises, The active electrode should be inspected for damage, including impaired insulation, at the operative field before use.

Yet, current modalities in many facilities don't provide for testing in the operating room. In spite of all advice to the contrary, final inspection of instrument insulation is traditionally done in the Central Sterile department, prior to a tray's final packing and sterilization cycle. The dangers are two-fold. First, most insulation defects are microscopic in size, and so not readily visible to the naked eye. It is these very pinhole-sized imperfections that can cause the most damage, because the energy is so concentrated, it tends to literally explode out of the perforation into the patient, yet these miniscule flaws are usually undetected. Secondly, already thinning insulation is subject to deteriorate completely during that final processing cycle because of the assault of chemicals and high temperatures. The set is then delivered to the operating room, where no one is aware that an instrument may have become compromised and is now unsafe.

During a laparoendoscopic procedure, only about 10% of an insulated instrument is visible on the video monitor at any one time, which means about 90% of that electrode remains outside the surgeon's field of view, where it can cause the most damage. When a defective instrument is introduced into the patient, electric current can escape to contiguous tissue or organs, but the surgeon is not aware that a thermal burn at a peripheral site has occurred. In fact, it is estimated that 67% of such injuries are not recognized at surgery. Unfortunately, manifestations of these unsuspected injuries don't appear until several days after the actual surgery and so, when the impaired patient presents, his or her clinical symptoms are already severe. Diagnosis is difficult and often delayed, and the damage can be irreversible. Complications include perforated organs, permanent disfigurement, and in an estimated 28% of fecal peritonitis cases, even death.

Certainly, because of the very biophysics of minimally invasive electrosurgery, there are other operatives that can result in thermal tissue abuse, such as capacitive coupling or direct coupling, but insulation failure is the most alarming because it is highly preventable. Anecdotal evidence suggests that, without proactive intervention, over 30% of laparoscopic instruments in any given facility have defective insulation. Ruptures in insulation are routine, and are even commonly found on single-use, disposable instruments.

In fact, all insulated electrodes should be considered suspicious, unless adequate safety measures are introduced. The traditional system for inspection in the sterile processing department is hardly foolproof, and its weaknesses must be addressed. Because the margin for error is so great, risk managers and physicians alike are insisting on alternatives that will ensure patient safety and reduce liability exposure.

To preclude claims of negligence, medical providers must put into place a series of procedures that can, to the fullest extent possible, effectively protect a patient from the risk of accidental thermal injury caused by damaged insulation. Certainly, instruments must be inspected prior to packing for sterilization, and pulled from the set when defects are discovered. This should be only one step in the process, however, since pinholes in the insulation are virtually impossible to detect under cursory examination.

Precautions should also include routine microscopic inspection by one's repair vendor, and an electronic scan if they have the proper technological means to do it. It's important to learn what device they use for scanning because some are outdated and can actually inflict further damage to the insulation. A common testing device, L.I.T., has been recalled by its manufacturer for that reason. A properly equipped repair technician should be able to demonstrate to you any defects he or she identified, and then re-insulate the instruments immediately. Even following re-insulation, they should be scanned to ensure proper application.

Finally, however, the only absolute safeguard is to test for insulation defects in the operating room, after the set has been opened. Both reusable and single use electrodes should be inspected preoperatively and postoperatively, and the results should be recorded in the surgical record. . . . A significant cause of injuries from active electrode insulation defects is failure to identify existing insulation defects on electrodes before surgery,� advise authors in Health Devices magazine.

This step can significantly reduce the number of accidental electrosurgical burns because it will prevent an otherwise unwitting surgeon from inserting a potentially lethal instrument into the patient. Insulation that degraded during that final sterilization cycle cannot be detected until this point in time, so it is critical that inspection in the operating room itself be made an integral part of hospital protocol. One device on the market, InsulScan™, is notable, in that it is approved for use in the operating room. Using sterile, disposable testing wands, it takes only seconds to scan a set of instruments for invisible insulation defects.

It is advisable to keep a supply of single-use electrodes available to replace any found to be faulty during the preoperative scan. In lieu of stocking such inventory, one can also devise a vigorous and ongoing inspection plan with a qualified repair vendor, to ensure that all reusable electrosurgical tools are scanned and reinsulated as needed. Certainly, a replacement would then be available from another set when problematic instruments are discovered in the operating room prior to a case.

If the instruments are re-scanned in the operating room following surgery, the surgeon can be secure in the knowledge that no stray electrical current escaped into adjacent, but unseen sites, and so if any post-op clinical complications were to arise, he or she could more easily isolate the cause. Conversely, if the postoperative scan revealed that insulation was damaged during the procedure, he or she may elect to take aggressive steps to investigate further. For documentation purposes, the results of both scans can be recorded in the patient record.

The fact is that a defective electrode can instantly and irreversibly imperil a patient. Delegating full responsibility for averting such disaster to the technicians in the Central Sterile Processing department places them in an untenable situation, simply because it is impossible to guarantee intact insulation on instruments that will undergo sterilization following inspection.

Enlightened managers no longer accept that liability and appreciate that responsibility for final inspection is a function best performed by the perioperative staff, in the surgery suite itself.

Surgeons, subject to malpractice claims resulting from accidental thermal burn, are also insisting on enhanced precautions to protect them and their patients, as well. Thirteen percent of members of The Society of Laparoscopic Surgeons surveyed said they had one or more malpractice cases involving a laparoscopic electrosurgical procedure

Hospitals and surgery centers remain accountable even if they don't know an in instrument is defective. . . . With liability risks for instrument malfunction equal to those for surgeon error, it would be prudent for hospitals to ensure that they have an adequate system in place for maintaining equipment and testing it for insulation degradation.�

Most importantly, there are preventive measures available today that didn't exist years ago. Consequently, traditional defenses against related lawsuits are no longer viable in the courtroom. Electrosurgical mishaps are common enough to have given rise to a Laparoscopic Surgery subgroup of the Association of Trial Lawyers of America, which consists of over 130 attorneys dedicated to pursuing litigation arising from thermal burning in minimally invasive lap/endo procedures.

There is indeed, a formidable risk. The Central Sterile department continues to be vital in the detection of defective instruments, but with the availability of technological innovations on the market today, it no longer must be the final authority. It remains the role of the C.S. tech to identify those readily visible defects on instruments so they can be sent for routine reinsulation. To have the most profound impact on patient safety, however, cautious and informed facilities recognize that the definitive challenge for uncovering microscopic flaws in insulation lies beyond the realistic capabilities of even the very best Central Service team.

Enlisting the support of the perioperative staff is critical. If equipped with the proper tools, all electrosurgery patients and their surgeons can proceed with confidence, that every available step to prevent straying electrical current has been taken. For their peace of mind and that of all instrument processing personnel, it is welcome clinical breakthrough.