Introduction Several studies have shown that maximizing stroke volume (or increasing it until a plateau is reached) by volume loading during high-risk surgery may improve post-operative outcome. This goal could be achieved simply by minimizing the variation in arterial pulse pressure (ΔPP) induced by mechanical ventilation. We tested this hypothesis in a prospective, randomized, single-centre study. The primary endpoint was the length of postoperative stay in hospital.

Patients exposed to a surgical safety checklist experience better postoperative outcomes, but this could simply reflect wider quality of care in hospitals where checklist use is routine.

Aims: To evaluate whether procalcitonin (PCT) and C reactive protein (CRP) are able to discriminate between sepsis and systemic inflammatory response syndrome (SIRS) in critically ill children. Methods: Prospective, observational study in a paediatric intensive care unit. Kinetics of PCT and CRP were studied in patients undergoing open heart surgery with cardiopulmonary bypass (CPB) (SIRS model; group I 1 ) and patients with confirmed bacterial sepsis (group II). Results: In group I, PCT median concentration was 0.24 ng/ml (reference value ,2.0 ng/ml). There was an increment of PCT concentrations which peaked immediately after CPB (median 0.58 ng/ml), then decreased to 0.47 ng/ml at 24 h; 0.33 ng/ml at 48 h, and 0.22 ng/ml at 72 h. CRP median concentrations remained high on POD1 (36.6 mg/l) and POD2 (13.0 mg/l). In group II, PCT concentrations were high at admission (median 9.15 ng/ml) and subsequently decreased in 11/14 patients who progressed favourably (median 0.31 ng/ml). CRP levels were high in only 11/14 patients at admission. CRP remained high in 13/14 patients at 24 h; in 12/14 at 48 h; and in 10/14 patients at 72 h. Median values were 95.0, 50.9, 86.0, and 20.3 mg/l, respectively. The area under the ROC curve was 0.99 for PCT and 0.54 for CRP. Cut off concentrations to differentiate SIRS from sepsis were .2 ng/ ml for PCT and .79 mg/l for CRP. Conclusion: PCT is able to differentiate between SIRS and sepsis while CRP is not. Moreover, unlike CRP, PCT concentrations varied with the evolution of sepsis.

No abstract

In anesthetized patients without cardiac arrhythmia the arterial pulse pressure variation (PPV) induced by mechanical ventilation has been shown the most accurate predictor of fluid responsiveness. In this respect, PPV has so far been used mainly in the decision-making process regarding volume expansion in patients with shock. As an indicator of the position on the Frank-Starling curve, PPV may actually be useful in many other clinical situations. In patients with acute lung injury or with acute respiratory distress syndrome, PPV can predict hemodynamic instability induced by positive end-expiratory pressure and recruitment maneuvers. PPV may also be useful to prevent excessive fluid restriction/depletion in patients with pulmonary edema, and to prevent excessive ultrafiltration in critically ill patients undergoing hemodialysis or hemofiltration. In the operating room, a goal-directed fluid therapy based on PPV monitoring has the potential to improve the outcome of patients undergoing high-risk surgery.In the previous issue of Critical Care, Keyl and colleagues [1] have investigated the effects of cardiac resynchronization therapy on arterial pulse pressure variation (PPV). Many studies [2] have shown that PPV is much more accurate than cardiac filling pressures and volumetric markers of preload to predict fluid responsiveness (that is, the hemodynamic effects of volume loading). PPV is also more reliable than other dynamic parameters such as systolic pressure variation [3,4] or pulse contour stroke volume variation [4]. In this respect, PPV is used increasingly in the decision-making process regarding volume expansion in patients with hemodynamic instability [2]. Limitations to the use of PPV do exist (mainly active breathing, cardiac arrhythmia, and low tidal volume) and have been described in detail elsewhere [2,5].It is very important to point out that PPV is not an indicator of volume status, nor a marker of cardiac preload, but is an indicator of the position on the Frank-Starling curve [2].Briefly, patients operating on the flat portion of the Frank-Starling curve are insensitive to cyclic changes in preload induced by mechanical inspiration, such that PPV is low (Figure 1). Conversely, PPV is high in patients operating on the steep portion of the preload/stroke volume relationship (and hence sensitive to cyclic changes in preload induced by mechanical inspiration) (Figure 1). This information has so far been used mainly to predict fluid responsiveness in patients with shock, but actually could be useful in many other clinical situations. PPV and fluid depletion/restrictionAs an indicator of the position on the Frank-Starling curve, PPV is as useful to predict the deleterious hemodynamic effects of fluid depletion as it is to predict the beneficial effects of fluid loading [6]. In critically ill patients undergoing hemodialysis or hemofiltration the volume of ultrafiltration is often determined roughly on the basis of body weight gain or fluid balance, and is further adjusted in case of hemodynam...