What are some general benefits of laparoscopic surgery compared to traditional open surgery?
Postoperative pain control requirements are approximately 4 times less than with traditional open incisions. Hospital stays have been decreased by 50%, and the time to full convalescence has been reported to be markedly less than with open removal. The laparoscopic approach has been shown to have less blood loss, shorter hospital stay, lower analgesic requirement, and shorter convalescence compared to traditional surgery.
What are the absolute contraindications to perform laparoscopy?
Any contraindication that would preclude surgery by another approach (ie, severe uncompensated cardiopulmonary disease or uncorrected coagulopathy), significant abdominal wall infection, generalized peritonitis, suspected malignant ascites, massive hemoperitoneum or hemoretroperitoneum, and intestinal obstruction unless intention is to treat at the same time.
What is the standard gas used for insufflation during laparoscopy and what properties of this gas make it the gas of choice?
Carbon dioxide (CO2) because it is colorless, odorless, nonflammable, and a readily available gas that is rapidly absorbed into the systemic circulation and quickly eliminated by the lungs.
What is the standard insufflation (intrabdominal) pressure (IAP) and why was this particular pressure selected?
• Fifteen (15) mm Hg is the standard insufflation pressure.
• Studies have shown cardiopulmonary, renal, and splanchnic effects are minimal and still reversible at an insufflation pressure of ≤15 mm Hg.
Can insufflation pressures ever be safely increased higher than 15 mm Hg? If so, what are the indications?
• Brief increases in intra-abdominal pressure, up to 20 mm Hg, are tolerable for most patients.
• Briefly increasing intra-abdominal pressure can be a helpful maneuver to control intraoperative venous oozing. Central venous pressures range from –1 to 5 cm H2O and the tamponade effect provided by a slightly higher IAP can yield better visualization by providing a clearer operative field in times of bleeding. Once hemostasis has been achieved, intra-abdominal pressure should be returned to 15 mm Hg.
• Increased preload from increased venous return to the heart with initial increased intra-abdominal pressure. This leads to increased cardiac output, increased stroke volume, and increased mean arterial pressure.
• With continued increased intra-abdominal pressure the venous return to the heart decreases, along with increased arterial resistance, that causes a decreased stroke volume with resultant increased heart rate.
• The overall physiologic response is that there is no clinically significant change in cardiac output—assuming normovolemia and intra-abdominal pressure ≤ 15 mm Hg.
Immediately upon peritoneal insufflation and prior to any operative steps, the anesthesiologist notes severe bradycardia and hypotension. What is the most likely cause and treatment?
The most likely cause is vagal stimulation due to abrupt peritoneal stretching. Immediate treatment is to desufflate the abdomen. Anesthesia can give atropine-like agents to reverse the bradycardia.
Can pneumoperitoneum cause cardiac arrhythmias?
• Carbon dioxide can elicit a sympathetic response, thus leading to tachycardia, vasoconstriction (via stimulation of the renin–angiotensin pathway), and potentially a cardiac arrhythmia.
• The above processes are exacerbated by acidosis.
What are the pulmonary effects of pneumoperitoneum?
• There are mechanical and metabolic effects.
• Mechanical: Increased intra-abdominal pressures have direct influence on the thoracic cavity by impairing diaphragmatic movement, increasing intrathoracic pressures, and decreasing respiratory compliance. This leads to an increase in airway pressures and a decrease in vital capacity.
• Metabolic: CO2 absorption leads to hypercarbia and acidosis.
What are the risks of laparoscopy on a patient with chronic obstructive pulmonary disease (COPD)?
Severe hypercarbia, due to baseline impairment of CO2 elimination in patients with COPD.
How should CO2 levels be monitored intraoperatively on patients with pulmonary compromise?
Arterial CO2 levels should be checked every 1 to 2 hours. Expired CO2 levels are unreliable in the presence of COPD due to the diffusion barrier. Arterial blood gas sampling should be continued postoperatively due to continued risk of hypercarbia after extubation due to subsequent mobilization of procedurally absorbed CO2.
If hypercarbia develops intraoperatively, what steps can be performed to correct the problem?
Lowering insufflation pressures from 15 mm Hg to just 10 to 12 mm Hg may be helpful. If this fails to correct the hypercarbia, then the insufflation gas should be changed to helium or more likely the surgery should be converted to an open procedure.
What are the renal effects of pneumoperitoneum?
Impaired glomerular filtration rate, creatinine clearance, sodium excretion, and decreased urine output. There is no permanent renal impairment and all of these problems are reversible with desufflation.
Decreased renal blood flow due to direct compression of the renal vasculature and inferior vena cava from the increased intra-abdominal pressure and direct renal parenchymal compression.
Should the oliguria during laparoscopic cases be managed initially with increased intravenous fluids?
Since the oliguria is transient, the patient should not be over-hydrated as this can lead to fluid overload, CHF, and respiratory compromise.
For prolonged laparoscopic cases, how can the oliguria be addressed to maintain adequate urine output?
Pharmacologic modalities can be used to prevent intraoperative oliguria:
• Furosemide (Lasix) (mg dose = 20 times the patient’s creatinine).
• Mannitol (12.5-25 g).
• Dopamine at 2 μg/kg/min.
What are the splanchnic effects of pnuemoperitoneum?
• Decreased blood flow has been reported in abdominal organs including the liver, pancreas, stomach, spleen, small intestine, and the colon.
• Delayed mesenteric thrombosis has also been reported, but is not a common complication of laparoscopic surgery.
Is pregnancy a contraindication to laparoscopy?
No, pregnancy is no longer considered a contraindication to laparoscopy.
What are the preferred sites of laparoscopic access for pregnant patients and should any special technique or approach be used?
Access should be gained by the Hasson technique in the left or right upper quadrant in the subcostal midclavicular line above the uterine fundus.
Are there any changes needed in insufflation pressures for pregnant patients and what levels would be considered potentially dangerous?
Insufflation pressures should be kept as low as possible but still allow for adequate visualization and operative space. IAPs >20 mm Hg have significant cardiopulmonary risks to mother and fetus.
Is obesity a contraindication to laparoscopic surgery?
No, obesity is not considered a contraindication to laparoscopy.
Are prior abdominal surgeries and/or intra-abdominal adhesions contraindications to laparoscopy?
• No, laparoscopy has been shown to be a safe method for lysis of intra-abdominal adhesions with significantly fewer wound complications with faster convalescence and return of bowel function than open lysis of adhesions.
• Primary intra-abdominal access should be gained at an area away from prior incisions, which have the greatest likelihood of underlying adhesions.
• The Hasson technique should be used to gain intra-abdominal access if it is felt that access cannot be gained safely with the Veress needle.
Smaller diameter = Less light transmission (darker image). A darker image may be worsened with blood in the operative field as blood absorbs light.
Where should the laparoscopic tower (insufflator, camera box, and light source) be positioned relative to the surgeon?
• All components should be in the surgeon’s line of view.
• This allows the surgeon to have the ability to assess any equipment-related problems.
Where should the monitor(s) with the laparoscopic images be positioned relative to the surgeon?
• In the surgeon’s direct line of vision at a comfortable distance.
• The monitor should be slightly below eye level and at a slight angle toward the surgeon—most ergonomic position and minimizes neck strain.
If additional monitors are available, where should they be positioned?
Additional monitors should be placed opposite the assistant if the surgeon and assistant are on opposite sides of the table. Extra monitors can also be placed opposite the surgical scrub technician to allow him/her to anticipate the surgeon’s needs and assist more efficiently.
What is a Veress needle and how does it work?
• A Veress needle is a needle that contains a spring-loaded superficial protective sheath.
• The sheath retracts as the needle is advanced through tissue exposing the needle tip.
• Once the needle enters the peritoneal cavity, and the majority of the resistance on the needle is released, the sheath springs forward and covers the needle.
• When the sheath covers the needle tip, it protects the intra-abdominal organs from being injured by the sharp end of the needle.
Describe the correct technique for gaining laparoscopic access when using the Veress needle.
• Examination of the Veress needle sheath to ensure it retracts.
• Flushing of the Veress needle to ensure it is patent.
• Pass the Veress needle through abdominal wall with gentle constant pressure.
• Irrigate the needle with saline, aspirate to look for blood, allow a drop of saline to drain by gravity through the needle (“drop test”).
• Connect the needle to CO2 insufflation.
• Once the intra-abdominal pressure reaches 15 mm Hg, withdraw the Veress needle.
• Insert the primary trocar followed by the laparoscope and inspect the abdomen for potential organ and/or vascular injury.
What should be the initial opening pressures of the intraperitoneal space?
< 10 mm Hg, usually 5 to 7 mm Hg.
How many clicks should be felt and/or heard when passing the Veress needle through the abdominal wall and what does each click represent?
Two clicks is optimal representing the abdominal wall fascia and the parietal peritoneum.
Confirmation that the distal tip of the Veress needle is within a low-pressure space.
Describe how to perform the “drop test” after the Veress needle has been passed through the abdominal wall.
• Attach a saline-filled syringe to the Veress needle.
• Aspiration of the needle to confirm no blood, cloudy aspirate, etc.
• Irrigation into the Veress needle of 1 to 2 mL of saline.
• Repeat aspiration of the needle again. No fluid should aspirate.
• Gently advance the needle 0.5 cm. No resistance should be felt.
• Remove the syringe from the needle.
• Fluid within the needle should drop rapidly into the abdominal cavity.
When insufflating through the Veress needle, should you use low-flow or high-flow and explain why.
• High-flow should be used.
• The size of the Veress needle limits flow to 1.5 to 2 L/min, so low-flow is not needed.
If initial insufflation pressures are greater than 10 mm Hg, what is the next step?
• The Veress needle should be withdrawn slightly (generally means that it’s in the mesentery or omentum).
• If the insufflation pressure drops to <10 mm Hg, continue insufflation as this indicates that the needle tip was against an intra-abdominal structure.
• If the pressure remains ≥ 10 mm Hg, the needle is not properly placed and should be removed and the above algorithm for initial insertion repeated.
Describe the Hasson technique for gaining laparoscopic access.
• A small skin incision is made at the planned trocar location.
• Dissection to fascia is performed.