Effect of acute normovolemic hemodilution combined with controlled hypotension on extravascular lung water and oxygenation in elderly orthopaedic surgery patients / 临床麻醉学杂志

ABSTRACT

Objective To investigate the effect of acute normovolemic hemodilution (ANH) combined with controlled hypotension (CH) on the extravascular lung water (EVLW) and oxygenation in elderly orthopaedic surgery patients.Methods Forty-five elderly orthopaedics surgery patients,23 males,22 females,aged 65-75 years old,ASA grade Ⅰ or Ⅱ,were randomly divided into 3 groups (n=15 each).Group A,served as control,received regular routine transfusion and intraoperative crystalloid fluids and colloidal liquid to add volume.Group B,namely ANH group,received normovolemic hemodilution till Hct reaching 30% after induction of anesthesia.Group C,ANH combined with CH group,received ANH with Hct reaching 30% after induction of anesthesia,and the patients were continuously pumped nitroglycerin combined with esmolol for controlled hypotension.The target mean arterial pressure controlled and cut by 30% below the basic value.We collected arterial blood for blood gas analysis at 5 points before before induction of anesthesia (T1),immediately after ANH (T2),30 min after ANH (T3),30 min after CH (T4),immediately after surgery (T5).Meanwhile the MAP,HR,PaO2,SpO2,Hct,HCO3-,pH,cardiac index (CI),stroke volume variation (SVV),stroke volume index (SVI),extravascular lung water index (EVLWI) and intrathoracic blood volume index (ITBVI) were recorded.Blood loss,urine output after surgery and the operation time were also recorded.Results The volumes of autoblood removed had no significant difference between group B and group C,and no autoblood was removed in group A.The volume of blood loss in group C was significantly less than that in group A and group B (P<0.05).Six cases in group A,one case in group B and none in group C needed homologous allogeneic blood transfusion.Compared with T1,MAP,HR,CI,SVI and Hct were significantly decreased at T2-T5 (P<0.05),but all those are stable in the normal range.Compared with T1,SVV was significantly decreased at T2-T4 (P<0.05).Compared with T1,ITBVI,PaO2 and SpO2 were increased at T2-T5 (P<0.05),but all those are stable in the normal range.CI and SVI at T2 in group A was significantly lower than that in group B and C.Compared with group A and B,MAP at T4 in group C were significantly decreased and SVV at T4 in group C were significantly increased(P<0.05).Urine output,the operation time,EVLWI,HCO3-and pH in three groups had no significant difference.Conclusion Acute normovolemic hemodilution combined with controlled hypotension has an effect of saving blood in elderly patients,without any influence on the extravascular lung water and oxygenation,which can be used safely in elderly patients which they are monitored.