Sample collection and processing To determine the present status of the internal environment, arterialized capillary blood was drawn from the fingertip at the time of patients' transfer from the operating room to the ICU (Time 0), and again at 2 hours and 6 hours from Time 0. The collected blood was tested in the laboratory using the Astrup method to measure the following parameters: pH, BE, actual bicarbonate (aBi), standard bicarbonate (sBi), partial pressure of oxygen (pO2) and carbon dioxide (pCO2). The obtained values were entered into a table and statistically analyzed. Both patients groups were adjusted for age and length of surgery to allow their comparison.