Position of diaphragm in the region of electrical impedance tomography measurement is to be determined by ultrasound in approx. 20 patients undergoing laparoscopic surgery. Data are to be obtained at three phases at supine horizontal position (during spontaneous breathing, at mechanically ventilated patient under general anesthesia with muscle relaxation and at mechanically ventilated patient under general anesthesia with muscle relaxation during insufflation of carbon dioxide into the peritoneal cavity to achieve exposure during laparoscopic surgery).

During laparoscopic surgery, insufflation of carbon dioxide into the peritoneal cavity is conducted in order to optimize working space for surgeons. As a side effect, the abdominal pressure alters physiological thoraco-abdominal configuration and pushes the diaphragm and lungs cranially. Since lung image acquired by electrical impedance tomography (EIT) depends on the conditions within the thorax and abdomen, it is crucial to know the diaphragm position to analyze the effect of cranial shift of diaphragm on EIT images of the thorax. Presence of diaphragm in the region of EIT measurement is to be determined by ultrasound in approx. 20 patients undergoing laparoscopic surgery. Data are to be obtained at three phases at supine horizontal position (during spontaneous breathing, at mechanically ventilated patient under general anesthesia with muscle relaxation and at mechanically ventilated patient under general anesthesia with muscle relaxation during insufflation of carbon dioxide into the peritoneal cavity to achieve exposure during laparoscopic surgery). The results of this study will serve during design of a subsequent study dealing with optimization of EIT electrode belt position during laparoscopic surgery.

Inclusion Criteria:

- patients undergoing abdominal laparoscopic surgery

Exclusion Criteria:

• morbid obesity
• standard exclusion criteria for electrical impedance tomography according to the manufacturer