[The experimental evidence of waveform information in arterial blood gas by beat-by-beat sampling method in human body-the differences of waveform information between arterial and venous blood samples].

Objective

The arterial blood with the oscillatory information comes from the right heart system after gas exchanging in the lung. However, the evidence of the waveform of venous ABG is lack. The objectives of this article are to compare the different information between arterial and venous beat-by-beat blood sample at the same time.

Methods

Six post-operative patients with normal heart function and negative Allen test, had been placed the arterial catheterization and central venous catheterization directly connected to pre-heparin plasticpipes for continuous collecting arterial and venous blood. We twisted the 2 pipes into helix formation. After drawing arterial and venous blood with syringes in one heart beat with one helix at the same time, totally 15 heart beats, clipping the pipes with forceps, we put the helix pipe into icedwater at once and analyses PaO2, PaCO2, pH and SaO2 as soon as possible. We selected two breathscycles of waveform from each patient for data calculations of magnitudes and time interval.

Results

The heart beat numbers for drawing blood into pipe were 15~16, and all covered more than 2 breathing cycles. There were significant changes of arterial PaO2(i.e. the highest high values compare to the next lowestvalues, P<0.05), but no significant changes in venous blood(P>0.05). The magnitudes of changing PaO2 in arterial and venous blood sample were (9.96±5.18)mmHg and (1.63±0.41)mmHg with significant variance(P=0.010), and they were (8.09±2.43)% and (3.91±1.22)%from their mean with significant variance(P=0.009) respectively.

Conclusion

With continuous beat-by-beat arterial and venous blood sampling and ABG analyzing method at the same time, we obtain a clear evidence of periodic parameters ABG waveform, which following breathing cycle, but no clear ABG waveform of the periodic parameters in the venous blood samples, which implies the oscillatory information of the arterial blood with comes from the gas exchanging in the lung.