Cardiac surgery patients present considerable variation in pre-operative hemodynamic variables.
BACKGROUND
It is essential to control hemodynamics in cardiac surgery. Patients are often monitored extensively in order to optimize hemodynamic performance. However, pre-operative values are normally unknown. Furthermore, hemodynamic goals may seem arbitrary and the lack of an evidence-based consensus may lead to both under- and over-treatment. The aim of this study was to evaluate the variables most commonly used for hemodynamic guidance in the post-operative period.


METHODS
Ten patients scheduled for elective cardiac surgery were followed with invasive hemodynamic monitoring the night before surgery. All data were recorded automatically and electronically.


RESULTS
We found considerable inter-patient differences and intra-patient variation. The greatest intra-patient variation was found in the cardiac index (CI), ranging from 1.9 to 5.3 l/min/m(2). Four patients had periodic CI <2.4 l/min/m(2). Eight patients showed SpO2 values < or =92, four of them in more than 15% of the observations. Six patients had an SvO2 <70% in more than 40% of the observations and two an SvO2 < 64% in more than 20% of the observations.


CONCLUSIONS
This study is unique because hemodynamic reference data in cardiac surgery patients have not been published previously. The intra-patient variations were unexpectedly high in most hemodynamic variables and demonstrate the difficulties of using hemodynamic parameters as a guidance for treatment and indicate that goal-oriented therapy using currently accepted values may result in over-treatment in some patients.
Sloth
E
E
Anesthesia & Intensive Care Medicine, Aarhus University Hospital, Skejby, Denmark.
Lindskov
C
C
Lorentzen
A-G
AG
Nygaard
M
M
Kure
H H
HH
Jakobsen
C-J
CJ
D000368:Aged; D001794:Blood Pressure; D002302:Cardiac Output; D006348:Cardiac Surgical Procedures / Q000379:methods*; D017558:Elective Surgical Procedures / Q000379:methods; D005260:Female; D006339:Heart Rate; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods / Q000706:statistics & numerical data*; D010100:Oxygen / Q000097:blood; D011183:Postoperative Complications / Q000517:prevention & control*; D011300:Preoperative Care / Q000379:methods* / Q000706:statistics & numerical data*
D010100:Oxygen