Laproflattor
The electronic CO2 Laproflattor is a general-purpose insufflation unit for use in laparoscopic examinations and operations. Controlled pressure insufflation of the peritoneal cavity is used to achieve the necessary workspace for laparoscopic surgery by distending the anterolateral abdominal wall and depressing the hollow organs and soft tissues. Carbon dioxide is the preferred gas because it does not support combustion. It is very soluble which reduces the risk of gas embolism, and is cheap. Automatic insufflators allow the surgeon to preset the insufflating pressure, and the device supplies gas until the required intra-abdominal pressure is reached. The insufflator activates and delivers gas automatically when the intra-abdominal pressure falls because of gas escape or leakage from the ports. The required values for pressure and flow can be obtained using jog keys and digital displays. Insufflation pressure can be continuously varied from 0 to 30 mm Hg; total gas flow rate and volumes can be set to any value in the range 0 to 45 liters/minute.
Patient safety is ensured by optical and acoustic alarms as well as several mutually independent safety circuits. The detail function and Quadro-manometric indicators of insufflators are important to understand the safety point of view. The important indicators of insufflators are preset pressure, actual pressure, flow rate, and total gas used.
Quadro manometric Indicators
Quadro-manometric indicators are the four important readings of the insufflator.
The insufflator is used to monitor
• Preset Insufflation pressure,
• Actual Pressure
• Gas flow rate and
• Volume of gas consumed
Preset Pressure
This is the pressure adjusted by the surgeon before starting insufflation. This is the command given by the surgeon to insufflator to keep intra-abdominal pressure at this level.
The preset pressure ideally should be 12 to 15 mm of Hg. In any circumstance, it should not be more than 18 mm of mercury in laparoscopic surgery. However, in extraperitoneal surgery, preset pressure can be used more than 18mm Hg. The good quality microprocessor controlled insufflator always keeps intra-abdominal pressure at a preset pressure. Whenever intra-abdominal pressure decreases due to leaking of gas outside, insufflator ejects some gas inside to maintain the pressure equal to preset pressure, and if intra-abdominal pressure increases due to external pressure, insufflator sucks some gas from the abdominal cavity to again maintain the pressure to preset pressure.
When a surgeon or gynecologist wants to perform diagnostic laparoscopy under local anesthesia, the preset pressure should be set to 8 mm of Hg. In some special situations of axilloscopy or arthroscopy, we need to have pressure more than 19mmHg.
Actual Pressure
This is the actual intra-abdominal pressure sensed by the insufflator. When veress needle is attached there is some error in actual pressure reading because of resistance of the flow of gas through the small caliber of veress needle. Since continuous flow of insufflating gas through veress needle usually gives an extra 4 to 8 mm Hg of measured pressure by insufflator, the true intra-abdominal pressure can actually be determined by switching the flow from insufflator off for a moment. Much microprocessor-controlled good quality insufflator deliver a pulsatile flow of gas when veress needle is connected, in which the low reading of actual pressure measures the true intra-abdominal pressure.
If there is any major gas leak actual pressure will be less and the insufflator will try to maintain the pressure by ejecting gas through its full capacity.
Actual pressure if more than 20 to 25mm of Hg has the following disadvantage over the hemodynamic status of the patient.
• Decrease venous return due to vena cava compression leading to
1. Increased chance of DVT (Deep vein thrombosis of calf)
2. Hidden cardiac ischemia can precipitate due to decreased cardiac output
• Decrease tidal volume due to diaphragmatic excursion
• Increase risk of air embolism due to venous intravasation
• Increased risk of surgical emphysema
• Decreased Renal perfusion
Flow rate
This reflects the rate of flow of CO2 through the tubing of the insufflator. When veress needle is attached the flow rate should be adjusted for 1 liter per minute. The experiment was performed over an animal in which direct I.V. CO2 was administered and it was found that the risk of air embolism is less if the rate is within 1 liter/minute. At the time of access using veress needle technique sometimes, veress needle may inadvertently enter inside a vessel but if the flow rate is 1 liter/minute there is less chance of serious complication. When initial pneumoperitoneum is achieved and the cannula is inside the abdominal cavity the insufflators flow rate may be set at maximum, to compensate for the loss of CO2 due to the use of suction irrigation instrument. This should be remembered that if the insufflator is set to its maximum flow rate then also it will allow flow only if the actual pressure is less than preset pressure otherwise it will not pump any gas. Some surgeon keeps initial flow rate with veress needle to 1 liter/minute and as soon as they confirm that gas is going satisfactorily inside the abdominal cavity (Percussion examination and seeing obliteration of liver dullness) then they increase the flow rate. No matter how much flow rate you set for veress needle, the eye of the normal caliber veress needle can give way CO2 flow at a maximum 2.5liter/minute. When the flow of CO2 is more than 7 liters/minute inside the abdominal cavity through a cannula, there is always a risk of hypothermia to the patient. To avoid hypothermia in all modern microprocessor-controlled laproflattor there is an electronic heating system that maintains the temperature of CO2.
Total Gas used
This is the fourth indicator of the insufflator. Normal size human abdominal cavity needs 1.5 liter CO2 to achieve intra-abdominal actual pressure of 12 mm Hg. In some big size abdominal cavity and in multipara patients sometimes we need 3 liters of CO2 (rarely 5 to 6 liters) to get the desired pressure of 12mm Hg. Whenever there is less or more amount of gas is used to inflate a normal abdominal cavity, the surgeon should suspect some error in the pneumoperitoneum technique. These errors may be a leak or maybe pre-peritoneal space creation or extravasations of gas. The detaileded principles and techniques of safe access are discussed in the access technique chapter of this book.
The electronic CO2 Laproflattor is a general-purpose insufflation unit for use in laparoscopic examinations and operations. Controlled pressure insufflation of the peritoneal cavity is used to achieve the necessary workspace for laparoscopic surgery by distending the anterolateral abdominal wall and depressing the hollow organs and soft tissues. Carbon dioxide is the preferred gas because it does not support combustion. It is very soluble which reduces the risk of gas embolism, and is cheap. Automatic insufflators allow the surgeon to preset the insufflating pressure, and the device supplies gas until the required intra-abdominal pressure is reached. The insufflator activates and delivers gas automatically when the intra-abdominal pressure falls because of gas escape or leakage from the ports. The required values for pressure and flow can be obtained using jog keys and digital displays. Insufflation pressure can be continuously varied from 0 to 30 mm Hg; total gas flow rate and volumes can be set to any value in the range 0 to 45 liters/minute.
Patient safety is ensured by optical and acoustic alarms as well as several mutually independent safety circuits. The detail function and Quadro-manometric indicators of insufflators are important to understand the safety point of view. The important indicators of insufflators are preset pressure, actual pressure, flow rate, and total gas used.
Quadro manometric Indicators
Quadro-manometric indicators are the four important readings of the insufflator.
The insufflator is used to monitor
• Preset Insufflation pressure,
• Actual Pressure
• Gas flow rate and
• Volume of gas consumed
Preset Pressure
This is the pressure adjusted by the surgeon before starting insufflation. This is the command given by the surgeon to insufflator to keep intra-abdominal pressure at this level.
The preset pressure ideally should be 12 to 15 mm of Hg. In any circumstance, it should not be more than 18 mm of mercury in laparoscopic surgery. However, in extraperitoneal surgery, preset pressure can be used more than 18mm Hg. The good quality microprocessor controlled insufflator always keeps intra-abdominal pressure at a preset pressure. Whenever intra-abdominal pressure decreases due to leaking of gas outside, insufflator ejects some gas inside to maintain the pressure equal to preset pressure, and if intra-abdominal pressure increases due to external pressure, insufflator sucks some gas from the abdominal cavity to again maintain the pressure to preset pressure.
When a surgeon or gynecologist wants to perform diagnostic laparoscopy under local anesthesia, the preset pressure should be set to 8 mm of Hg. In some special situations of axilloscopy or arthroscopy, we need to have pressure more than 19mmHg.
Actual Pressure
This is the actual intra-abdominal pressure sensed by the insufflator. When veress needle is attached there is some error in actual pressure reading because of resistance of the flow of gas through the small caliber of veress needle. Since continuous flow of insufflating gas through veress needle usually gives an extra 4 to 8 mm Hg of measured pressure by insufflator, the true intra-abdominal pressure can actually be determined by switching the flow from insufflator off for a moment. Much microprocessor-controlled good quality insufflator deliver a pulsatile flow of gas when veress needle is connected, in which the low reading of actual pressure measures the true intra-abdominal pressure.
If there is any major gas leak actual pressure will be less and the insufflator will try to maintain the pressure by ejecting gas through its full capacity.
Actual pressure if more than 20 to 25mm of Hg has the following disadvantage over the hemodynamic status of the patient.
• Decrease venous return due to vena cava compression leading to
1. Increased chance of DVT (Deep vein thrombosis of calf)
2. Hidden cardiac ischemia can precipitate due to decreased cardiac output
• Decrease tidal volume due to diaphragmatic excursion
• Increase risk of air embolism due to venous intravasation
• Increased risk of surgical emphysema
• Decreased Renal perfusion
Flow rate
This reflects the rate of flow of CO2 through the tubing of the insufflator. When veress needle is attached the flow rate should be adjusted for 1 liter per minute. The experiment was performed over an animal in which direct I.V. CO2 was administered and it was found that the risk of air embolism is less if the rate is within 1 liter/minute. At the time of access using veress needle technique sometimes, veress needle may inadvertently enter inside a vessel but if the flow rate is 1 liter/minute there is less chance of serious complication. When initial pneumoperitoneum is achieved and the cannula is inside the abdominal cavity the insufflators flow rate may be set at maximum, to compensate for the loss of CO2 due to the use of suction irrigation instrument. This should be remembered that if the insufflator is set to its maximum flow rate then also it will allow flow only if the actual pressure is less than preset pressure otherwise it will not pump any gas. Some surgeon keeps initial flow rate with veress needle to 1 liter/minute and as soon as they confirm that gas is going satisfactorily inside the abdominal cavity (Percussion examination and seeing obliteration of liver dullness) then they increase the flow rate. No matter how much flow rate you set for veress needle, the eye of the normal caliber veress needle can give way CO2 flow at a maximum 2.5liter/minute. When the flow of CO2 is more than 7 liters/minute inside the abdominal cavity through a cannula, there is always a risk of hypothermia to the patient. To avoid hypothermia in all modern microprocessor-controlled laproflattor there is an electronic heating system that maintains the temperature of CO2.
Total Gas used
This is the fourth indicator of the insufflator. Normal size human abdominal cavity needs 1.5 liter CO2 to achieve intra-abdominal actual pressure of 12 mm Hg. In some big size abdominal cavity and in multipara patients sometimes we need 3 liters of CO2 (rarely 5 to 6 liters) to get the desired pressure of 12mm Hg. Whenever there is less or more amount of gas is used to inflate a normal abdominal cavity, the surgeon should suspect some error in the pneumoperitoneum technique. These errors may be a leak or maybe pre-peritoneal space creation or extravasations of gas. The detaileded principles and techniques of safe access are discussed in the access technique chapter of this book.
