The most common arrhythmia seen during laparoscopy is:
The pressure effects of the pneumoperitoneum on cardiovascular physiology also have been studied. In the hypovolemic individual, excessive pressure on the inferior vena cava and a reverse Trendelenburg position with loss of lower extremity muscle tone may cause decreased venous return and cardiac output. This is not seen in the normovolemic patient. The most common arrhythmia created by laparoscopy is bradycardia. A rapid stretch of the peritoneal membrane often causes a vagovagal response with bradycardia and occasionally hypotension. The appropriate management of this event is desufflation of the abdomen, administration of vagolytic agents ( eg, atropine), and adequate volume replacement.
To avoid thermal injury to adjacent structures, the laparoscopic field of view must include all uninsulated portions of the electrosurgical electrode. In addition, the integrity of the insulation must be maintained and assured. Capacitive coupling occurs when a plastic trocar insulates the abdominal wall from the current; in turn the current is bled off a metal sleeve or laparoscope into the viscera (Fig. below ). This may result in thermal necrosis and a delayed fecal fistula. Another potential mechanism for unrecognized visceral injury may occur with the direct coupling of current to the laparoscope and adjacent bowel.
Capacitive coupling occu rs as a result of high cu rrent density bleeding from a port sleeve or laparoscope i nto adjacent bowel.
Which of the following are true regarding safe laparoscopic surgery in pregnancy?
Concerns about the safety of laparoscopic cholecystectomy and appendectomy in the pregnant patient have been thoroughly investigated and readily managed. Access to the abdomen in the pregnant patient should take into consideration the height of the uterine fundus, which reaches the umbilicus at 20 weeks. In order not to damage the uterus or tis blood supply, most surgeons feel that the open (Hasson) approach should be used in favor of direct puncture laparoscopy. The patient should be positioned slightly on the left side to avoid compression of the vena cava by the uterus. Because the pregnancy poses a risk for thromboembolism, sequential compression devices are essential for all procedures. Surgery should be performed in the second trimester, if possible. Protection of the fetus against intraoperative X-rays is imperative.
Systemic effects of CO2 from pneumoperitoneum can cause all of the following EXCEPT:
Alterations in preload are local effects (pressure specific) of CO2 peritoneum. The physiologic effects of CO2 pneumoperitoneum can be divided into two areas (1) gas-specific effects and (2) pressurespecific effects (Fig. below) . CO2 is rapidly absorbed across the peritoneal membrane into the circulation. In the circulation, CO2 creates a respiratory acidosis by the generation of carbonic acid. Body buffers, the largest reserve of which lies in bone, absorb CO2 (up to 120 L) and minimize the development of hypercarbia or respiratory acidosis during brief endoscopic procedures. Once the body buffers are saturated, respiratory acidosis develops rapidly, and the respiratory system assumes the burden of keeping up with the absorption of CO2 and its release from these buffers. In patients with normal respiratory function, this is not difficult; the anesthesiologist increases the ventilatory rate or vital capacity on the ventilator. If the respiratory rate required exceeds 20 breaths per minute, there may be less efficient gas exchange and increasing hypercarbia. Conversely, if vital capacity is increased substantially, there is a greater opportunity for barotrauma and greater respiratory motion-induced disruption of the upper abdominal operative field. In some situations, it is advisable to evacuate the pneumoperitoneum or reduce the intra-abdominal pressure to allow time for the anesthesiologist to adjust for hypercarbia. Although mild respiratory acidosis probably is an insignificant problem, more severe respiratory acidosis leading to cardiac arrhythmias has been reported. Hypercarbia also causes tachycardia and increased systemic vascular resistance, which elevates blood pressure and increases myocardial oxygen demand.
Carbon dioxide gas insufflated into the peritoneal cavity has both loca l and systemic effects that cause a complex set of hemodynamic and metabolic alterations.
While performing a laparoscopic Nissen fundoplication during the transhiatal dissection the mediastinal pleura is compromised and a CO2 pneumothorax develops. What is the initial preferred management of the pneumothorax?
When a pneumothorax occurs with laparoscopic Nissen fundoplication or Heller myotomy, it is preferable to place an 18-French red rubber catheter with multiple holes cut out of the distal end across the defect. At the end of the procedure, the distal end of the tube is pulled out a 10-mm port side (as the port is removed), and the pneumothorax is evacuated to a primitive water-seal using a bowl of sterile water or saline.
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