Non-invasive Hemoglobin Measurement In Patients Undergoing Spinal Fusion

Objectives:To compare the accuracy between noninvasive hemoglobin measurement(SpHb)and arterial blood gas analyzer(Thbc), and evaluate the influences of noninvasive hemoglobin measurement(SpHb) in patients undergoing spinal fusion, make sure whether it can be used in intraoperative transfusion decision-making.Method:Fifty-three patients undergoing selective surgery of posterior spine fusion,ASAⅠto Ⅲ,were enrolled the study.They received general anesthesia in the prone position. Noninvasive hemoglobin measurement(SpHb), Arterial blood gas analyzer(Thbc), Automated laboratory hemoglobin(Hb), duration of surgery,bleeding,perfusion index(PI), mean arterial pressure(MAP), central venous pressure(CVP),body temperature( ℃) the situation of fluid infusion were obtained immediately before the incision of skin, the bone graft fusion, at the end of the surgery and bleeding each of more than 400 ml. Bland-Altman analysis, linear regression and non-parametric tests were used for statistical analysis.Results:(1) Bland-Altman analysis show that the agreement between SpHb and Hb is weaker than between Thbc and Hb.(2) The linear regression shows that SpHb was positively correlated with Hb(r=0.77,p<0.05) and THbc was higher positively correlated with Hb(r=0.89,p<0.05).(3) Non-parametric tests displayed significance differences between the difference of SpHb and Hb,Thbc and Hb.(4) The accuracy with SpHb was affected by the factors such as perfusion index(PI), bleeding and colloid infusion( p < 0.05),but was not age,duration of surgery,central venous pressure,crystal infusion,body temperature and mean arterial pressure(p>0.05).Conclusion:SpHb is able to response plasma hemoglobin concentration change trend, and help to provide reference of when to start to blood transfusion. The accuracy of SpHb was affected by many factors. To decide when to blood transfusion depends on SpHb combination with THbc or Hb.