Influence of different volume therapies on platelet function in the critically ill

Both albumin and synthetic colloids such as hydroxyethyl starch (HES) solution are used to optimize hemodynamics in the critically ill. The influence of different long-term infusion regimes on platelet function was studied.

Prospective, randomized study.

Clinical investigation on a university hospital surgical intensive care unit.

Twenty-eight consecutive trauma patients (injury severity score > 15 points) and 28 consecutive nontraumatized surgical patients with sepsis.

The patients received either 20% human albumin (HA trauma, n = 14; HA sepsis, n = 14) or 10% low-molecular-weight HES solution HES 200/0.5 (HES trauma, n = 14; HES sepsis; n = 14) for 5 days to maintain central venous pressure and/or pulmonary capillary wedge pressure between 12 and 16 mmHg.

Platelet function was assessed by aggregometry (= turbidimetric technique) using adenosine diphosphate 2.0 mumol/l, collagen 4 microliters/ml, and epinephrine 25 mumol/l as inductors. Arterial blood was sampled on the day of admission or the day of diagnosis of sepsis (= baseline value) and over the next 5 days. Standard coagulation parameters (antithrombin III, fibrinogen, partial thromboplastin time) were also measured. Total use of HES by the 5th day totalled 4870 +/- 990 ml in the trauma and 3260 +/- 790 ml in the sepsis patients (HA trauma: 1850 +/- 380 ml; HA sepsis: 1790 +/- 400 ml). Maximum platelet aggregation decreased significantly during the first 2-3 days after baseline in all groups. At the end of the investigation period, platelet aggregation variables had recovered and reached (or even exceeded) baseline values. Within the entire investigation period, the course of platelet aggregation variables did not differ significantly between HA and HES-treated patients irrespective of whether they were trauma or sepsis patients.

Alterations in hemostasis may occur for several reasons in the critically ill. Human albumin is the preferred first-line volume therapy in patients at risk for coagulation disorders. With respect to platelet function, volume replacement with (lower-priced) low-molecular-weight HES solutions can be recommended in this situation without any risk.