A nomogram to evaluate the arterial mixed venous oxygen saturation difference during cardiopulmonary bypass
1998; SAGE Publishing; Volume: 13; Issue: 1 Linguagem: Inglês
10.1177/026765919801300106
ISSN1477-111X
Autores Tópico(s)Optical Imaging and Spectroscopy Techniques
ResumoA nomogram providing the arterial mixed venous haemoglobin saturation difference (S a-v O 2 ) corresponding to normal oxygen consumption (VO 2 ) during cardiopulmonary bypass (CPB) was produced. Normal VO 2 during CPB (95.8 ± 20.1 ml/min/m 2 at 37°C) was obtained from the literature. The nomogram computes the S a-v O 2 from the body surface, pump flow, blood haemoglobin and patient temperature; a table is also presented which supplies the S a-v O 2 ranges corresponding to VO 2 mean ±1 and ±2SD. The nomogram was tested on 10 subjects undergoing CPB for myocardial revascularization. S a-v O 2 was determined by arterial and mixed venous blood oximetry 5, 20, and 35 min after the start of CPB. The measured S a-v O 2 was 27.1 ± 7.2% while S a-v O 2 obtained from the nomogram was 24.9 ± 4.0%, the difference was not statistically significant. Eighteen values (60%) were within the range corresponding to VO 2 mean ±1SD. One value was lower than the S a-v O 2 value corresponding to VO 2 mean - 2SD and was associated with the lowest value of blood haemoglobin. Two values were higher than the S a-v O 2 value corresponding to VO 2 mean + 2SD and were associated with inadequate muscle relaxation. By comparing measured S a-v O 2 values with those obtained by the nomogram and the table, anaesthesiologists and perfusionists can easily detect patients presenting abnormally low or high VO 2 values.
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