Cardiopulmonary Bypass (CPB), a non-physiological 
intervention that maintains the blood circulation outside the 
body, brings about hemodynamic and biochemical changes, 
but these have not been elucidated in detail. Therefore, the 
aim of this study was a thorough examination of the changes 
in hemodynamic and biochemical parameters in patients at 
each stage of coronary bypass graft surgery (T1; before 
induction of anesthesia; T2: before CBP; T3: 5 min before 
placement of the cross clamp; T4: 5 min after removal of the 
cross clamp; T5: upon admission to intensive care; T6: 24 h 
post-operation). Pulmonary artery pressure, Mean Pulmonary 
Artery Pressure (MPAP), Central Venous Pressure (CVP), 
and Pulmonary Capillary Wedge Pressure (PCWP) were 
monitored and measured using a Swan-Ganz catheter 
introduced via the jugular vein at five of the six periods (not 
the period before anesthesia was induced). Mean Arterial 
Pressure (MAP) was monitored and measured through an 
arterial line. The blood lactate level was quantified during 
the same time periods using a blood gas device: it fell before 
the placement of the cross clamp (40 mmHg), but increased 
after the clamp was removed and rose to 80-100 mmHg at 24 
h post-operation. The heart rate decreased after anesthesia  was normal in all other periods. CVP also declined slightly 
after removal of the cross clamp (T4), but remained in the 
normal range during the remaining periods. The MPAP and 
PCWP values were in the normal range throughout all steps 
during the bypass. Among the biochemical parameters, 
only lactate exhibited a noteworthy change. Lactate levels 
increased significantly in the T1-T3 period but gradually 
returned to normal in T4 (5 min after removal of the cross 
clamp). We contend that it is essential to measure 
hemodynamic parameters and lactate levels in order to 
track the physiological changes in patients during a 
successful CPB operation.