ºÝºÝߣ

ºÝºÝߣShare a Scribd company logo

Can Surgerybe Made Safer Cm

•Download as DOC, PDF•
•
C
cem50

Surgery has evolved from traditional open procedures to minimally invasive techniques like laparoscopy. Laparoscopy uses small incisions and a laparoscope for visualization instead of large incisions. Advances in insufflation equipment allow surgeons to establish and maintain pneumoperitoneum, or gas in the abdominal cavity, to improve visualization. New disposable tubing and filters prevent foreign gases from entering the body and fluids from exiting, improving safety. Membrane technology has also advanced, with hydrophobic membranes that allow gas to pass but block liquids and pathogens. Further developments include filters that can evacuate surgical smoke containing particles to prevent filter clogging and cross contamination. These advances aim to make surgery safer for both patients and operating room personnel

1 of 3
Download to read offline
Can Surgery be Made Safer ? Charles E Meisch Managing Partner NBS Medical Products Inc. Surgery is the branch of medicine dealing with manual operative procedures for the correction of deformities, defects, injuries, and the diagnosis of certain diseases. Traditionally, these procedures required open surgery known as a laparotomy. Within the last few years minimally invasive surgery, specifically laparoscopy which deals with the abdomen, has become a replacement for many open procedures. Many of the general procedures are performed using a rigid scope placed into the abdominal cavity by small trocars. A mini scope is inserted allowing direct visual observation. Additional trocars create space for micro instruments to repair, remove, or diagnose problems without large surgical cuts in the abdomen. What is laparoscopy? Laparoscopy is abdominal exploration using a type of endoscope called a laparoscope. To improve visualization of the peritoneal cavity and ease instrument manipulation during laparoscopy, the abdominal cavity must first be filled with an insufflating gas producing a pneumoperitoneum. Laparoscopic insufflators are specialized pressure-limiting gas flow regulators that make it easy to establish and maintain a pneumoperitoneum. To establish the pneumoperitoneum, one end of a piece of low-pressure tube ranging in length from approximately 8 to 10 ft is connected to the insufflator outlet port. The other end of the tube is connected to an insufflation needle called a Veress needle. Advances in Filters and Membranes Early insufflators used reusable silicone tubing (generally one-quarter inch I.D.) that allowed CO2 gas to flow from the insufflator through the tube and into the patient. Within the last 10 years it became obvious that foreign gases going into the body should be filtered and bodily fluids that might accidentally flow back through the tube should be stopped prior to going into the insufflator. Once into the insufflator, it becomes difficult to clean and recondition these expensive units. Most Endoscopic companies who sell insufflators now offer them with disposable tubing containing filters. The filters are usually rated at .1 micron but can be anywhere from .1 to .3 microns and should be hydrophobic. When using low flow insufflators (9.9 to 15 l/min), standard off the shelf gas filters are sufficient. But at the 20, 30, or 40 l/min range, special filters are required. Some companies developed unique filters. As the insufflator cycles gas into the filter it should not directly hit a flat filter membrane (flat meaning the filter housing itself is flat in nature encompassing the membrane). A baffle system is necessary to give gas, as the insufflator cycles, enough time to get through the filter and not excessively cause back pressure, which could momentarily and prematurely shut off the insufflator. Some flat filters, or using the wrong membranes cause problems with the operation of the equipment, false shut downs, and allowing overpressure alarms to go off. Other problems are false readings due to lack of flow from the filter. The blocking of the filter, or other obstacles in the pathway may not allow achievement of accurate pneumoperitoneum. Membranes themselves have also evolved. Filter companies can design gas filters that are hydrophobic both in the respiratory and in the Insufflation area. Filters are available that produce the optimum amount of
flow at the least amount of cost. Using a flat filter on a high flow insufflator at 1.8 to 2 cycles per second can damage the filter and not let gas pass through or reach filter micron size. Insufflators have also improved from 9.9 to 30 liters per minute, or even higher flow rates. They all function in a similar nature and contain sophisticated electronic feedback devices. Once set, high-flow units fill the peritoneum to the appropriate pressure and maintain it as the body absorbs some of the gas. Trocars may also leak some gas. Aside from the geometry of the filter itself testing will clearly show that trying to push a high flow of gas through a 1/4 inch hole with no reservoir becomes virtually impossible. Along with the geometry of the filter housing, filter membranes also evolved. Aerosol droplets can bypass filters malfunctioning insufflators. This also increases maintenance, physically restricts airflow, and more seriously may lead to bacterial growth in the insufflator. During the late 1950's, membrane technology expanded. Osmotic transfer of salts across the membrane began in the area of desalinization and has lead into kidney dialysis. Membranes could be designed to pass air but not pass water and also filter out aerosols and bacteria from the air stream. This membrane would be an analogous to a toy that makes soap bubbles where a water film forms in a hoop. As air blows into the hoop a pressure differential causes the film to bulge out and form a bubble. Reducing hoop diameter increases the differential pressure (not force) needed to distort the film, creating a fine net the size of the original hoop. With the differential pressure increase the total force across the net is higher. Another characteristic to consider is hydrophobicity. Air would be free to move through the net until the net was touched by a liquid which would form a film blocking the movement of air until the differential pressure across the net was too great or the liquid was evaporated. Obviously, the net would have to be some material which would cause liquid to form a film across the intercies. The specific composition of membranes with these properties is generally a trade secret of the membrane manufacturer, however, the most common material is Teflon. The Teflon sheet is either mechanically perforated or stretched to form tears or holes in the material. Another method is to coat a netlike substrate with a chemical, generally a silicone compound. This creates a hydrophobic membrane that lets air flow freely until the membrane is wetted. At this point air-flow is stopped as long as pressure differential is below the maximum level. Air-flow through the filter must be maintained by the membrane. The membrane must have sufficient small intercies to stop or entrap aerosol fluids and microbes. Microbes are carried by the aerosol fluids. The membrane must be secured either mechanically or by heat sealing in the exit area of the filter. Test results of new membranes are encouraging. Air flows at a normal rate until liquid covers one side, when the filter shuts down. This saves the insufflator from damage. Bacteriological testing showed these membranes stopped pathogens and aerosols as well as any commercial microbial filters and met HEPA and ULPA criteria. Surgery Developments Surgery was not at a stand still during the development of new filters and membranes. New surgical tools were introduced that were micro in size along with both laser and electrical knives. Both tools minimize bleeding by
cauterizing while cutting, however they produce dense smoke in the abdomen. No one really knew what the smoke consisted of, but most agreed that it was best kept out of the air. The solution was to develop a new type of filter that could be connected to an exit port of a trocar and capture the smoke. Lab tests showed that in the presence of this dense smoke, filters not designed for smoke elimination could shut down in 30 seconds. Analysis of the smoke showed it contained proteins, peptides, amino acids, and other breakdown particles. In other tests, electron microscopic studies showed a layer of these breakdown products had formed over the surface of the membrane blocking airflow. Filter companies have spent a tremendous amount of time and money to develop an inexpensive yet disposable smoke evacuator. A filter that combines fluid stoppage along with smoke and bacterial filtration to cleanse the expelled gas is now available. It is obvious that this is needed to control cross contamination and infection and to protect operating personnel from smoke caused by laser and electro surgery. The designs have been rigorously tested and proven reliable. In the future, technology will continue to improve. This is just another stepping stone in the final attempt of surgeons to alleviate discomfort, shorten hospital stays, curtail cross contamination, and protect operating room personnel.

More Related Content

Can Surgerybe Made Safer Cm

  • 1. Can Surgery be Made Safer ? Charles E Meisch Managing Partner NBS Medical Products Inc. Surgery is the branch of medicine dealing with manual operative procedures for the correction of deformities, defects, injuries, and the diagnosis of certain diseases. Traditionally, these procedures required open surgery known as a laparotomy. Within the last few years minimally invasive surgery, specifically laparoscopy which deals with the abdomen, has become a replacement for many open procedures. Many of the general procedures are performed using a rigid scope placed into the abdominal cavity by small trocars. A mini scope is inserted allowing direct visual observation. Additional trocars create space for micro instruments to repair, remove, or diagnose problems without large surgical cuts in the abdomen. What is laparoscopy? Laparoscopy is abdominal exploration using a type of endoscope called a laparoscope. To improve visualization of the peritoneal cavity and ease instrument manipulation during laparoscopy, the abdominal cavity must first be filled with an insufflating gas producing a pneumoperitoneum. Laparoscopic insufflators are specialized pressure-limiting gas flow regulators that make it easy to establish and maintain a pneumoperitoneum. To establish the pneumoperitoneum, one end of a piece of low-pressure tube ranging in length from approximately 8 to 10 ft is connected to the insufflator outlet port. The other end of the tube is connected to an insufflation needle called a Veress needle. Advances in Filters and Membranes Early insufflators used reusable silicone tubing (generally one-quarter inch I.D.) that allowed CO2 gas to flow from the insufflator through the tube and into the patient. Within the last 10 years it became obvious that foreign gases going into the body should be filtered and bodily fluids that might accidentally flow back through the tube should be stopped prior to going into the insufflator. Once into the insufflator, it becomes difficult to clean and recondition these expensive units. Most Endoscopic companies who sell insufflators now offer them with disposable tubing containing filters. The filters are usually rated at .1 micron but can be anywhere from .1 to .3 microns and should be hydrophobic. When using low flow insufflators (9.9 to 15 l/min), standard off the shelf gas filters are sufficient. But at the 20, 30, or 40 l/min range, special filters are required. Some companies developed unique filters. As the insufflator cycles gas into the filter it should not directly hit a flat filter membrane (flat meaning the filter housing itself is flat in nature encompassing the membrane). A baffle system is necessary to give gas, as the insufflator cycles, enough time to get through the filter and not excessively cause back pressure, which could momentarily and prematurely shut off the insufflator. Some flat filters, or using the wrong membranes cause problems with the operation of the equipment, false shut downs, and allowing overpressure alarms to go off. Other problems are false readings due to lack of flow from the filter. The blocking of the filter, or other obstacles in the pathway may not allow achievement of accurate pneumoperitoneum. Membranes themselves have also evolved. Filter companies can design gas filters that are hydrophobic both in the respiratory and in the Insufflation area. Filters are available that produce the optimum amount of
  • 2. flow at the least amount of cost. Using a flat filter on a high flow insufflator at 1.8 to 2 cycles per second can damage the filter and not let gas pass through or reach filter micron size. Insufflators have also improved from 9.9 to 30 liters per minute, or even higher flow rates. They all function in a similar nature and contain sophisticated electronic feedback devices. Once set, high-flow units fill the peritoneum to the appropriate pressure and maintain it as the body absorbs some of the gas. Trocars may also leak some gas. Aside from the geometry of the filter itself testing will clearly show that trying to push a high flow of gas through a 1/4 inch hole with no reservoir becomes virtually impossible. Along with the geometry of the filter housing, filter membranes also evolved. Aerosol droplets can bypass filters malfunctioning insufflators. This also increases maintenance, physically restricts airflow, and more seriously may lead to bacterial growth in the insufflator. During the late 1950's, membrane technology expanded. Osmotic transfer of salts across the membrane began in the area of desalinization and has lead into kidney dialysis. Membranes could be designed to pass air but not pass water and also filter out aerosols and bacteria from the air stream. This membrane would be an analogous to a toy that makes soap bubbles where a water film forms in a hoop. As air blows into the hoop a pressure differential causes the film to bulge out and form a bubble. Reducing hoop diameter increases the differential pressure (not force) needed to distort the film, creating a fine net the size of the original hoop. With the differential pressure increase the total force across the net is higher. Another characteristic to consider is hydrophobicity. Air would be free to move through the net until the net was touched by a liquid which would form a film blocking the movement of air until the differential pressure across the net was too great or the liquid was evaporated. Obviously, the net would have to be some material which would cause liquid to form a film across the intercies. The specific composition of membranes with these properties is generally a trade secret of the membrane manufacturer, however, the most common material is Teflon. The Teflon sheet is either mechanically perforated or stretched to form tears or holes in the material. Another method is to coat a netlike substrate with a chemical, generally a silicone compound. This creates a hydrophobic membrane that lets air flow freely until the membrane is wetted. At this point air-flow is stopped as long as pressure differential is below the maximum level. Air-flow through the filter must be maintained by the membrane. The membrane must have sufficient small intercies to stop or entrap aerosol fluids and microbes. Microbes are carried by the aerosol fluids. The membrane must be secured either mechanically or by heat sealing in the exit area of the filter. Test results of new membranes are encouraging. Air flows at a normal rate until liquid covers one side, when the filter shuts down. This saves the insufflator from damage. Bacteriological testing showed these membranes stopped pathogens and aerosols as well as any commercial microbial filters and met HEPA and ULPA criteria. Surgery Developments Surgery was not at a stand still during the development of new filters and membranes. New surgical tools were introduced that were micro in size along with both laser and electrical knives. Both tools minimize bleeding by
  • 3. cauterizing while cutting, however they produce dense smoke in the abdomen. No one really knew what the smoke consisted of, but most agreed that it was best kept out of the air. The solution was to develop a new type of filter that could be connected to an exit port of a trocar and capture the smoke. Lab tests showed that in the presence of this dense smoke, filters not designed for smoke elimination could shut down in 30 seconds. Analysis of the smoke showed it contained proteins, peptides, amino acids, and other breakdown particles. In other tests, electron microscopic studies showed a layer of these breakdown products had formed over the surface of the membrane blocking airflow. Filter companies have spent a tremendous amount of time and money to develop an inexpensive yet disposable smoke evacuator. A filter that combines fluid stoppage along with smoke and bacterial filtration to cleanse the expelled gas is now available. It is obvious that this is needed to control cross contamination and infection and to protect operating personnel from smoke caused by laser and electro surgery. The designs have been rigorously tested and proven reliable. In the future, technology will continue to improve. This is just another stepping stone in the final attempt of surgeons to alleviate discomfort, shorten hospital stays, curtail cross contamination, and protect operating room personnel.