Hemoglobin trend in critically ill patients with long ICU stay

Background and Goal of Study: Critically ill patients develop anemia due to several reasons: bleeding prior or during ICU admission, frequent flebotomies, inflammatory status with altered erythropoiesis. The aim of the study was to assess the trend of hemoglobin (Hb) value during long ICU stay (>7 days) in transfused and non-transfused patients. Materials and Methods: All patients admitted during 1 year in a 19-bed mixed ICU of a tertiary care university hospital with a longer ICU length of stay (LOS) >7 days were enrolled. Patients were divided into two groups: never transfused (NT) and ever transfused (ET). Collected data: demographic data, severity scores, Hb value during ICU stay, transfusion status. Statistical analysis was conducted with SPSS. Results and Discussion: 132 patients were enrolled (54pts – NT, 78pts – ET).

Hb value at ICU admission was 10.1±3g% in NT and 8.5±2.8g% in ET group. In our group Hb transfusion trigger was 7.8±2.3g%. During ICU stay (day 0-day 21) mean Hb decreases with 0.94g% in NT group and with 0.89g% in ET group (non-significant difference).

Conclusion(s):
Despite the fact that Hb value at ICU admission may vary widely, after 14 days of ICU stay the Hb values tends to converge, disregarding if the patient received or not blood transfusion. The dispersion of Hb values within NT and ET group decreases over time (SD has decreased in both groups).

Anestesiology and Intensive Care, Nice University Hospital, Nice, France
Background and Goal of Study: Assessing volemia is a major concern during peri-operative period. The initial distribution volume of glucose (IDVG) is a method estimating circulating blood volume using the dilution of glucose.This volume consists in plasma and interstitial fluid of highly perfused organs. Estimation of IDVG is simple and minimally invasive. The aim of this preliminary work is to evaluate IDVG in predicting post operative hypovolemic hypotension after aortic surgery for aneurysm. Materials and Methods: After approval of our ethic committee and collection of appropriate consent, we prospectively included 22 patients after scheduled aortic surgery for aneurysm. The amount of per operative fluid infusion was decided by the attending anaesthesiologist aiming to maintain appropriate volemia. Post operatively, IDVG was estimated after injection of 5 grams of glucose and measurement of glycemia on arterial blood before injection and after 3, 4, 5, 6 minutes. IDVG was calculated using a pharmacokinetic one compartment model. During the first post operative day, we collected the hypovolemic hypotension events (systolic blood pressure < 90 mmHg responding to fluid challenge) and standard hemodynamic variables. For statistical analysis we used a Students t test and a Fisher test when appropriate. Results and Discussion: Nine patients showed a hypovolemic hypotension (HH) event post operatively. IDVG was statistically lower in this group of patients (82 21.9 vs. 116 24.3 ml/kg; p=0.004). Between the hypotensive and non hypotensive patients there was no difference in heart rate, urine output and central venous pressure < 5 cm of water. Between the 2 groups, there was no difference in per operative fluid infusion (3505 1740 in HH patients vs. 4130 1133 ml in non HH patients; p=0.34). With a threshold of 100 ml/kg, IDVG can predict the occurrence of hypovolemic hypotension with an 89% sensibility and 85% specificity.

Conclusion(s):
IDVG can predict the occurrence of hypovolemic hypotension after aortic surgery for aneurysm. This method could be a useful tool to optimize the fluid infusion peri operatively. This method need to be validated on a greater population and other types of surgery.

12AP4-10 Liberal versus restrictive fluid administration in a goal-directed strategy: Toward a logic of optimisation of the patient circulatory status?
E. Futier, J. Constantin, S. Cayot, L. Roszyk, J. Bazin

Background and Goal of Study:
Despite several studies concerning the influence of intraoperative fluid administration (liberal or restrictive) in high-risk surgery, the impact of such strategies has never been evaluated in a goaldirected strategy of optimisation the patient circulatory status. Taking into account the risk of altered tissue perfusion during hypovolemia, this prospective and randomised study was designed to evaluate the influence of two strategies (liberal and restrictive) integrated in a goal-directed therapy in terms of hypovolemia and postoperative organs dysfunctions.

Materials and Methods:
In this prospective study, 40 patients, ASA I-III, undergoing major abdominal surgery were randomised to 12 ml/kg/h (group Liberal, n=20) or 6 ml/kg/h (group Restrictive, n=20) intraoperative administration of cristalloids (NaCl 0,9% or Ringer lactate). In both groups, hemodynamic monitoring included oesophageal doppler, arterial pulse pressure variations (deltaPP) and oxygen delivery index (D02I). Hypovolemia were corrected by bolus of colloids (HES 130/0,4). Results and Discussion: Pre-operatively, group L and R were comparable in terms of demographic data, ASA, P-Possum, types and duration of surgery. The amount of cristalloid perfused was significantly lower in group R (median 3025 ml (2000-4500) vs 5570 ml (4000-8000), p<0,01). Compared with group L, hypovolemia as well as the amount of colloid necessary (125 ml (0-750) vs 625 ml (0-2000)) were significantly increased in group R (p<0,01). At the end of surgery, D02I was comparable in both groups (450±108 ml/min/m 2 vs 491±161 ml/min/m 2 , p=0,51). Post-operative complications were not significantly different in both group, except for the incidence of renal insufficiency (p<0,01) and a tendancy to an increase incidence of sepsis (p=0,07) in group R. Post-operative recovery was not different according to groups.

Conclusion(s):
Although promoted by recent work (1), according to the risk of hypovolemia, frequent and readily insidious, restrictive fluid administration expose to the risk of altered tissue perfusion and post-operative organ dysfunction. Early detection and correction of hypovomemia are fundamental. The application, in routine, of restrictive strategies of vascular filling does not seem to be able to be recommended within the framework of a more global strategy of optimization and monitoring of the hemodynamic profile of patients. References: