Functional intravascular volume deficit in patients before surgery

Stroke volume (SV) maximization with a colloid infusion, referred to as individualized goal-directed therapy, improves outcome in high-risk surgery. The fraction of patients who need intravascular volume to establish a maximal SV has, however, not been evaluated, and there are only limited data on the volume required to establish a maximal SV before the start of surgery. Therefore, we estimated the occurrence and size of the potential functional intravascular volume deficit in surgical patients.

Patients scheduled for mastectomy (n=20), open radical prostatectomy (n=20), or open major abdominal surgery (n=20) were anaesthetized, and before the start of surgery, a 200 ml colloid fluid challenge was provided and repeated if a >or=10% increment in SV estimated by oesophageal Doppler was established. The volume needed for SV maximization defined the intravascular volume deficit.

Forty-two (70%) of the patients needed volume to establish a maximal SV. For the patients needing volume, the required amount was median 200 ml (range 200-600 ml), with no significant difference between the three groups of patients. The required volume was >or=400 ml in nine patients (15%).

The majority of anaesthetized patients present with a functional intravascular volume deficit before surgery. Although the deficit in general was minor, a fraction of patients presented with a deficit that may be of clinical relevance, emphasizing the importance of the individual approach of goal-directed fluid therapy.