Introduction
With the development of mini-invasive technique, laparoscopic procedures form the basis of general surgery. After the introduction of laparoscopy in surgery, laparoscopic cholecystectomy has been adopted as the gold standard in the surgical treatment of cholelithiasis and gallbladder diseases (1). ”CO2 pneumoperitonium method” is used in exposing sufficient image and surgical field in laparoscopy. Usually, artificial pneumoperitoneum is established by carbon dioxide insufflation and intra-abdominal pressure (IAP) is often kept between 10 and 15 mmHg.
There are many advantages of laparoscopic cholecystectomy (such as short hospital stay, minimal postoperative pain, rapid recovery), as well as systemic disadvantages associated with increased intraabdominal pressure. In laparoscopic cholecystectomy procedures, cardiopulmonary changes may be observed due to the pneumoperitoneum (2). Since preload is significantly affected by IAP increase, it is important to determine the effect of IAP increase on fluid response in patients undergoing laparoscopic surgery (3).
Today, hemodynamic monitoring includes static parameters such as pulmonary capillary wedge pressure, central venous pressure, as well as dynamic parameters such as pulse pressure variation and stroke volüme variation (4). One of the dynamic parameters used to predict fluid response in mechanically ventilated patients is the pleth variability index (PVI) obtained by continuous and automatic calculation of pulse oximetry plethysmographic waveform variability during the respiratory cycle. The Masimo Radical-7 (Masimo Corporation, Irvine, CA) device provides an easy and continuous measurement using a finger probe. This device has been validated to predict fluid sensitivity in patients who are mechanically ventilated and undergo open abdominal surgery (5,6). A continuous, non-invasive Hb level monitoring is provided simultaneously with the same probe. This has also been shown to correlate with blood hg levels (7). As this device can be used non-invasively, it has become the preferred hemodynamic monitoring method for patient follow-up.
However, factors such as arrhythmia, hypothermia, spontaneous breathing activity, vasoactive drug use, and impaired peripheral perfusion limit the availability of PVI and SpHb monitoring (8). The ability of these dynamic parameters to predict fluid response and blood loss may be affected by respiratory, hemodynamic and physical changes that cause intrathoracic pressure change (9).
There are few studies examining the effect of pneumoperitoneum or obesity on the reliability of these monitors. Both factors have previously been shown to significantly affect cardiopulmonary physiology and function, which both potentially affect the performance and reliability of these devices (10). There are studies investigating the effects of both pneumoperitoneum and obesity in gastric bypass operations, but there is no study investigating the effects of pneumoperitoneum with equal intraabdominal pressures, in obese and non-obese patients (11). The aim of this study was to determine the effects of continuous CO2 pneumoperitoneum with a pressure of 12 mmHg and desufflation on non-invasive monitoring variables between obese and non-obese patients undergoing laparoscopic surgery.