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.