Cardiac filling volumes versus pressures for predicting fluid responsiveness after cardiovascular surgery: the role of systolic cardiac function

ABSTRACT: INTRODUCTION: Static cardiac filling volumes have been suggested to better predict fluid responsiveness than filling pressures, but this may not apply to hearts with systolic dysfunction and dilatation. We evaluated the relative value of cardiac filling volume and pressures for predicting and monitoring fluid responsiveness, according to systolic cardiac function, estimated by global ejection fraction (GEF, normal 25 to 35%) from transpulmonary thermodilution. METHODS: We studied hypovolemic, mechanically ventilated patients after coronary (n = 18) or major vascular (n = 14) surgery in the intensive care unit. We evaluated 96 colloid fluid loading events (200 to 600 mL given in three consecutive 30-minute intervals, guided by increases in filling pressures), divided into groups of responding events (fluid responsiveness) and non-responding events, in patients with low GEF ( <20%) or near-normal GEF (≥20%). Patients were monitored by transpulmonary dilution and central venous (n = 9)/pulmonary artery (n = 23) catheters to obtain cardiac index (CI), global end-diastolic volume index (GEDVI), central venous (CVP) and pulmonary artery occlusion pressure (PAOP). RESULTS: Fluid responsiveness occurred in 8 (≥15% increase in CI) and 17 (≥10% increase in CI) of 36 fluid loading events when GEF was <20%, and 7 (≥15% increase in CI) and 17 (≥10% increase in CI) of 60 fluid loading events when GEF was ≥20%. Whereas a low baseline GEDVI predicted fluid responsiveness particularly when GEF was ≥20% (P = 0.002 or lower), a low PAOP was of predictive value particularly when GEF was <20% (P = 0.004 or lower). The baseline CVP was lower in responding events regardless of GEF. Changes in CVP and PAOP paralleled changes in CI particularly when GEF was <20%, whereas changes in GEDVI paralleled CI regardless of GEF. CONCLUSIONS: Regardless of GEF, CVP may be useful for predicting fluid responsiveness in patients after coronary and major vascular surgery provided that positive end-expiratory pressure is low. When GEF is low ( <20%), PAOP is more useful than GEDVI for predicting fluid responsiveness, but when GEF is near-normal (≥20%) GEDVI is more useful than PAOP. This favors predicting and monitoring fluid responsiveness by pulmonary artery catheter-derived filling pressures in surgical patients with systolic left ventricular dysfunction and by transpulmonary thermodilution-derived GEDVI when systolic left ventricular function is relatively norma

Greater cardiac response of colloid than saline fluid loading in septic and non-septic critically ill patients with clinical hypovolaemia

Background and objective: The haemodynamics of crystalloid and colloid fluid loading may depend on underlying disease, i.e. sepsis versus non-sepsis. Design and setting: A single-centre, single-blinded, randomized clinical trial was carried out on 24 critically ill sepsis and 24 non-sepsis patients with clinical hypovolaemia, assigned to loading with normal saline, gelatin 4%, hydroxyethyl starch 6% or albumin 5% in a 90-min (delta) central venous pressure (CVP)-guided fluid loading protocol. Transpulmonary thermodilution was done each 30 min, yielding, among others, global end-diastolic volume and cardiac indices (GEDVI, CI). Results: Sepsis patients had hyperdynamic hypotension in spite of myocardial depression and dilatation, and greater inotropic/vasopressor requirements than non-sepsis patients. Independent of underlying disease, CVP and GEDVI increased more after colloid than saline loading (P < 0.018), so that CI increased by about 2% after saline and 12% after colloid loading (P = 0.029). The increase in preload-recruitable stroke work was also greater with colloids and did not differ among conditions. Conclusion: Fluid loading with colloids results in a greater linear increase in cardiac filling, output and stroke work than does saline loading, in both septic and non-septic clinical hypovolaemia, in spite of myocardial depression and presumably increased vasopermeability potentially decreasing the effects of colloid fluid loading in the former. © The Author(s) 2010

N-terminal-pro-brain natriuretic peptide elevations in the course of septic and non-septic shock reflect systolic left ventricular dysfunction assessed by transpulmonary thermodilution

Background: The cardiac correlates, if any, of N-terminal probrain natriuretic peptide (NT-proBNP) levels in septic and non-septic shock patients remain controversial. Methods: In the 38 septic and 22 non-septic shock patients in the transpulmonary thermodilution arm of a previous 2-center randomized controlled trial comparing pulmonary artery catheterization with transpulmonary thermodilution, serial (daily for 3 days) and paired measurements (n = 145) were obtained of NT-proBNP and transpulmonary dilution variables as global ejection fraction (GEF), left ventricular preload-recruitable stroke work (PRSW) and diastolic compliance. Results: Elevated NT-proBNP inversely related to low GEF and PRSW in pooled data (r = −0.45, P < 0.001). The 72 h course of NT-proBNP was inversely associated with PRSW, independent of age, gender, creatinine, norepinephrine treatment and diastolic compliance, without differences between septic and non-septic shock. Over the 72 h study period, NT-proBNP levels were higher in 28 day non-survivors than survivors, independent of type of shock and disease severity. Conclusions: In septic and non-septic shock, NT-proBNP elevations reflect systolic left ventricular dysfunction and are associated with a poor outcome. They may help recognition of cardiac dysfunction in shock and its management when invasive hemodynamic monitoring is not yet instituted

Electroencephalogram Predicts Outcome in Patients With Postanoxic Coma During Mild Therapeutic Hypothermia

Objective: To assess the value of electroencephalogram for prediction of outcome of comatose patients after cardiac arrest treated with mild therapeutic hypothermia. Design: Prospective cohort study. Setting: Medical ICU. Patients: One hundred forty-two patients with postanoxic encephalopathy after cardiac arrest, who were treated with mild therapeutic hypothermia. Measurements and Main Results: Continuous electroencephalogram was recorded during the first 5 days of ICU admission. Visual classification of electroencephalogram patterns was performed in 5-minute epochs at 12 and 24 hours after cardiac arrest by two independent observers, blinded for patients’ conditions and outcomes. Patterns were classified as isoelectric, low voltage, epileptiform, burst-suppression, diffusely slowed, or normal. Burst-suppression was subdivided into patterns with and without identical bursts. Primary outcome measure was the neurologic outcome based on each patient’s best achieved Cerebral Performance Category score within 6 months after inclusion. 67 patients (47%) had favorable outcome (Cerebral Performance Category, 1–2). In patients with favorable outcome, electroencephalogram patterns improved within 24 hours after cardiac arrest, mostly toward diffusely slowed or normal. At 24 hours after cardiac arrest, the combined group of isoelectric, low voltage, and “burst-suppression with identical bursts” was associated with poor outcome with a sensitivity of 48% (95% CI, 35–61) and a specificity of 100% (95% CI, 94–100). At 12 hours, normal or diffusely slowed electroencephalogram patterns were associated with good outcome with a sensitivity of 56% (95% CI, 41–70) and a specificity of 96% (95% CI, 86–100). Conclusions: Electroencephalogram allows reliable prediction of both good and poor neurologic outcome of patients with postanoxic encephalopathy treated with mild therapeutic hypothermia within 24 hours after cardiac arrest