Hollmann D. Aya

Goal-directed therapy in cardiac surgery: a systematic review and meta-analysis.

BACKGROUNDnPerioperative mortality after cardiac surgery has decreased in recent years although postoperative morbidity is still significant. Although there is evidence that perioperative goal-directed haemodynamic therapy (GDT) may reduce surgical mortality and morbidity in non-cardiac surgical patients, the data are less clear after cardiac surgery. The objective of this review is to perform a meta-analysis on the effects of perioperative GDT on mortality, morbidity, and length of hospital stay in cardiac surgical patients.nnnMETHODSnWe conducted a systematic review using Medline, EMBASE, and the Cochrane Controlled Clinical Trials Register. Additional sources were sought from experts. The inclusion criteria were randomized controlled trials, mortality reported as an outcome, pre-emptive haemodynamic intervention, and cardiac surgical population. Included studies were examined in full and subjected to quantifiable analysis, subgroup analysis, and sensitivity analysis where possible. Data synthesis was obtained by using odds ratio (OR) and mean difference (MD) for continuous data with 95% confidence interval (CI) utilizing a random-effects model.nnnRESULTSnFrom 4986 potential studies, 5 met all the inclusion criteria (699 patients). The quantitative analysis showed that the use of GDT reduced the postoperative complication rate (OR 0.33, 95% CI 0.15-0.73; P=0,006) and hospital length of stay (MD -2.44, 95% CI -4.03 to -0.84; P=0,003). There was no significant reduction in mortality.nnnCONCLUSIONnThe use of pre-emptive GDT in cardiac surgery reduces morbidity and hospital length of stay.

Effect of Early Vasopressin vs Norepinephrine on Kidney Failure in Patients With Septic Shock: The VANISH Randomized Clinical Trial

IMPORTANCEnNorepinephrine is currently recommended as the first-line vasopressor in septic shock; however, early vasopressin use has been proposed as an alternative.nnnOBJECTIVEnTo compare the effect of early vasopressin vs norepinephrine on kidney failure in patients with septic shock.nnnDESIGN, SETTING, AND PARTICIPANTSnA factorial (2×2), double-blind, randomized clinical trial conducted in 18 general adult intensive care units in the United Kingdom between February 2013 and May 2015, enrolling adult patients who had septic shock requiring vasopressors despite fluid resuscitation within a maximum of 6 hours after the onset of shock.nnnINTERVENTIONSnPatients were randomly allocated to vasopressin (titrated up to 0.06 U/min) and hydrocortisone (nu2009=u2009101), vasopressin and placebo (nu2009=u2009104), norepinephrine and hydrocortisone (nu2009=u2009101), or norepinephrine and placebo (nu2009=u2009103).nnnMAIN OUTCOMES AND MEASURESnThe primary outcome was kidney failure-free days during the 28-day period after randomization, measured as (1) the proportion of patients who never developed kidney failure and (2) median number of days alive and free of kidney failure for patients who did not survive, who experienced kidney failure, or both. Rates of renal replacement therapy, mortality, and serious adverse events were secondary outcomes.nnnRESULTSnA total of 409 patients (median age, 66 years; men, 58.2%) were included in the study, with a median time to study drug administration of 3.5 hours after diagnosis of shock. The number of survivors who never developed kidney failure was 94 of 165 patients (57.0%) in the vasopressin group and 93 of 157 patients (59.2%) in the norepinephrine group (difference, -2.3% [95% CI, -13.0% to 8.5%]). The median number of kidney failure-free days for patients who did not survive, who experienced kidney failure, or both was 9 days (interquartile range [IQR], 1 to -24) in the vasopressin group and 13 days (IQR, 1 to -25) in the norepinephrine group (difference, -4 days [95% CI, -11 to 5]). There was less use of renal replacement therapy in the vasopressin group than in the norepinephrine group (25.4% for vasopressin vs 35.3% for norepinephrine; difference, -9.9% [95% CI, -19.3% to -0.6%]). There was no significant difference in mortality rates between groups. In total, 22 of 205 patients (10.7%) had a serious adverse event in the vasopressin group vs 17 of 204 patients (8.3%) in the norepinephrine group (difference, 2.5% [95% CI, -3.3% to 8.2%]).nnnCONCLUSIONS AND RELEVANCEnAmong adults with septic shock, the early use of vasopressin compared with norepinephrine did not improve the number of kidney failure-free days. Although these findings do not support the use of vasopressin to replace norepinephrine as initial treatment in this situation, the confidence interval included a potential clinically important benefit for vasopressin, and larger trials may be warranted to assess this further.nnnTRIAL REGISTRATIONnclinicaltrials.gov Identifier: ISRCTN 20769191.

Changes in the mean systemic filling pressure during a fluid challenge in postsurgical intensive care patients

PurposeThe difference between mean systemic filling (Pmsf) and central venous pressure (CVP) is the venous return gradient (dVR). The aim of this study is to assess the significance of the Pmsf analogue (Pmsa) and the dVR during a fluid challenge.MethodsWe performed a prospective observational study in postsurgical patients. Patients were monitored with a central venous catheter, a LiDCO™plus and the Navigator™. A 250-ml intravenous fluid challenge was given over 5xa0min. A positive response to the fluid challenge was defined as either a stroke volume (SV) or cardiac output increase of greater than 10xa0%.ResultsA total of 101 fluid challenges were observed in 39 patients. In 43 events (42.6xa0%) the SV and CO increased by more than 10xa0%. Pmsa increased similarly during a fluid challenge in responders and non-responders (3.1xa0±xa01.9 vs. 3.1xa0±xa01.8, pxa0=xa00.9), whereas the dVR increased in responders (1.16xa0±xa00.8 vs. 0.2xa0±xa01, pxa0<xa00.001) as among non-responders CVP increased along with Pmsa (2.9xa0±xa01.7 vs. 3.1xa0±xa01.8, pxa0=xa00.15). Resistance to venous return did not change immediately after a fluid challenge. Heart performance (Eh) decreased significantly among non-responders (0.41xa0±xa00.15 vs. 0.34xa0±xa00.13, pxa0<xa00.001) whereas among responders it did not change when compared with baseline value (0.35xa0±xa00.15 vs. 0.34xa0±xa00.12, pxa0=xa00.15).ConclusionsThe changes in Pmsa and dVR measured at the bedside during a fluid challenge are consistent with the cardiovascular model described by Guyton.

Dynamic arterial elastance as a predictor of arterial pressure response to fluid administration: a validation study

IntroductionFunctional assessment of arterial load by dynamic arterial elastance (Eadyn), defined as the ratio between pulse pressure variation (PPV) and stroke volume variation (SVV), has recently been shown to predict the arterial pressure response to volume expansion (VE) in hypotensive, preload-dependent patients. However, because both SVV and PPV were obtained from pulse pressure analysis, a mathematical coupling factor could not be excluded. We therefore designed this study to confirm whether Eadyn, obtained from two independent signals, allows the prediction of arterial pressure response to VE in fluid-responsive patients.MethodsWe analyzed the response of arterial pressure to an intravenous infusion of 500xa0ml of normal saline in 53 mechanically ventilated patients with acute circulatory failure and preserved preload dependence. Eadyn was calculated as the simultaneous ratio between PPV (obtained from an arterial line) and SVV (obtained by esophageal Doppler imaging). A total of 80 fluid challenges were performed (median, 1.5 per patient; interquartile range, 1 to 2). Patients were classified according to the increase in mean arterial pressure (MAP) after fluid administration in pressure responders (≥10%) and non-responders.ResultsThirty-three fluid challenges (41.2%) significantly increased MAP. At baseline, Eadyn was higher in pressure responders (1.04u2009±u20090.28 versus 0.60u2009±u20090.14; P <0.0001). Preinfusion Eadyn was related to changes in MAP after fluid administration (R2u2009=u20090.60; P <0.0001). At baseline, Eadyn predicted the arterial pressure increase to volume expansion (area under the receiver operating characteristic curve, 0.94; 95% confidence interval (CI): 0.86 to 0.98; P <0.0001). A preinfusion Eadyn value ≥0.73 (gray zone: 0.72 to 0.88) discriminated pressure responder patients with a sensitivity of 90.9% (95% CI: 75.6 to 98.1%) and a specificity of 91.5% (95% CI: 79.6 to 97.6%).ConclusionsFunctional assessment of arterial load by Eadyn, obtained from two independent signals, enabled the prediction of arterial pressure response to fluid administration in mechanically ventilated, preload-dependent patients with acute circulatory failure.

Can (and should) the venous tone be monitored at the bedside

Purpose of reviewMost of our blood volume is contained in the venous compartment. The so-called ‘compliant veins’ are an adjustable blood reservoir, which is playing a paramount role in maintaining haemodynamic stability. The purpose of this study is to review what is known about this blood reservoir and how we can use this information to assess the cardiovascular state of critically ill patients. Recent findingsThe mean systemic filling pressure (Pmsf) is the pivot pressure of the circulation, and a quantitative index of intravascular volume. The Pmsf can be measured at the bedside by three methods described in critically ill patients. The Pmsf can be modified by the fluid therapy and vasoactive medications. SummaryThe Pmsf along with other haemodynamic variables can provide valuable information to correctly understand the cardiovascular status of critically ill patients and better manage the fluid therapy and cardiovascular support. Future studies using the Pmsf will show its usefulness for fluid administration.

Changes On Mean Systemic Filling Pressure And Microcirculation After a Fluid Challenge.

In a previous study we observed that a fluid challenge of 4 ml/Kg is adequate to raise the mean systemic filling pressure (Pmsf) and to increase venous return in fluid responsive patients.

Accuracy of an automatic analysis software to detect microvascular density parameters

Analysis of microvascular density parameters is time consuming and operator-dependent.1 This is the main limitation to use microvascular monitoring in clinical practice as a “point-of-care” tool. Recently, an automatic analysis software has been developed and could allow us to obtain results quickly.

From cardiac output to blood flow auto-regulation in shock

Shock is defined as a state in which the circulation is unable to deliver sufficient oxygen to meet the demands of the tissues, resulting in cellular dysoxia and organ failure. In this process, the factors that govern the circulation at a haemodynamic level and oxygen delivery at a microcirculatory level play a major role. This manuscript aims to review the blood flow regulation from macro- and micro-haemodynamic point of view and to discuss new potential therapeutic approaches for cardiovascular instability in patients in cardiovascular shock. Despite the recent advances in haemodynamics, the mechanisms that control the vascular resistance and the venous return are not fully understood in critically ill patients. The physical properties of the vascular wall, as well as the role of the mean systemic filling pressure are topics that require further research. However, the haemodynamics do not totally explain the physiopathology of cellular dysoxia, and several factors such as inflammatory changes at the microcirculatory level can modify vascular resistance and tissue perfusion. Cellular vasoactive mediators and endothelial and glucocalix damage are also involved in microcirculatory impairment. All the levels of the circulatory system must be taken into account. Evaluation of microcirculation may help one to detect under-diagnosed shock, and together with classic haemodynamics, guide one towards the appropriate therapy. Restoration of classic haemodynamic parameters is essential but not sufficient to detect and treat patients in cardiovascular shock.

Perioperative Haemodynamic Optimisation

During the latest years, a number of studies have confirmed the benefits of perioperative haemodynamic optimisation on surgical mortality and postoperative complication rate. This process requires the use of advanced haemodynamic monitoring with the purpose of guiding therapies to reach predefined goals. This review aim to present recent evidence on perioperative goal directed therapy (GDT), with an emphasis in some aspects that may merit further investigation. In order to maximise the benefits on outcomes, GDT must be implemented as early as possible; intravascular volume optimisation should be in accordance with the response of the preload-reserve, goals should be individualised and adequacy of the intervention must be also assessed; non-invasive or minimally invasive monitoring should be used and, finally, side effects of every therapy should be taken into account in order to avoid undesired complications. New drugs and technologies, particularly those exploring the venous side of the circulation, may improve in the future the effectiveness and facilitate the implementation of this group of therapeutic interventions.