The Warning Value Of Intraoperative Anemia With The Monitoring Of Continuous Noninvasive Hemoglobin Trending In Cytoreductive Surgery: A Prospective, Randomized, Controlled, Single Center Clinical Trail

Objective:The real-time anemia state is hard to be measured by intermittent invasive hemoglobin monitoring,which may lead to delayed or unnecessary transfusion.Pulse CO-Oximetry is one of the choices to monitor real-time total hemoglobin(spectrophotometric hemoglobin,Sp Hb)concentration.The purpose of this study is to investigate whether the continuous trending of Sp Hb can warn clinicians of substantial decline in hemoglobin concentration.Methods:A single-blined,randomized controlled trial was conducted.A total of 69 patients undergoing cytoreductive or scoliosis surgery in which estimated blood loss was over 15% of total blood volume were enrolled.Patients were randomly allocated to Sp Hb monitoring and standard care group.In Sp Hb monitoring group,blood draw for Co-Oximetry Hb(Co Ox Hb)was taken when Sp Hb decreased by 1g/dl.In standard care group,hemoglobin measurement was taken when clinicians thought it was necessary.Incidence that Co Ox Hb dropped to the upper limit of transfusion threshold(10g/dl)and Incidence that Co Ox Hb decreased by over 1g/dl were compared by Fisher’s exact test.Incidence that Co Ox Hb was beneath the lower limit(7g/dl)or decreased by more than 3g/dl was also compared.The relationship between Sp Hb and Co Ox Hb was assessed using Bland–Altman analysis,Error grid analysis,a 4-quadrant plot and linear regression.Total transfusion volume and postoperative hemoglobin concentration were compared by ANOVA analysis.Results: When Sp Hb went down by 1g/dl or more,the incidence that Co Ox Hb decreased by over 1g/dl was 93.3%(14/15)%.However,the incidence was only 54.5%(12/22)% when clinicians thought it was necessary to take a blood draw in the controlled group(P=0.002).When Sp Hb monitoring warned,the incidence of anemia(Co Ox Hb was below 10g/dl)was 86.67%(13/15)%,while only 50.00%(12/22)% in the controlled group(P=0.015).There was no case with serious anemia(Co Ox Hb was below 7g/dl)in the Sp Hb group.Total 60 Sp Hb–Co Ox Hb data pairs and 28 delta pairs(ΔSp Hb and ΔCo Ox Hb)were collected.The bias and precision of Sp Hb to Co Ox Hb were(-0.29±1.03)g/d L;the limits of agreement were(-2.30,1.72)g/dl.In error grid,90% of the data pairs were located in green region.To evaluate trending,the delta pairs(ΔSp Hb and ΔHb)were plotted,which revealed a positive correlation(ΔSp Hb = 0.489*ΔCo Ox Hb-0.13)with correlation coefficient r = 0.69,95% CI [confidence interval] =(0.53,0.82).There was no significant difference in total blood volume or postoperative anemia state between the two groups.Conclusions:1 Clinicians can tell if there is a substantial decline in hemoglobin concentration by observing the trending of noninvasive hemoglobin monitoring during intraoperative blood loss.2 Intraoperative Sp Hb monitoring can warn clinicians of anemia accurately and timely.3Though continuous noninvasive hemoglobin monitoring cannot replace invasive hemoglobin test,the trending of Sp Hb can show doctors how Co Ox Hb changes well.