Ebook Evidence based practice of critical care (2/E): Part 2
➤ Gửi thông báo lỗi ⚠️ Báo cáo tài liệu vi phạmNội dung chi tiết: Ebook Evidence based practice of critical care (2/E): Part 2
Ebook Evidence based practice of critical care (2/E): Part 2
40What MAP Objectives Should Be Targeted in Septic Shock?Francois Beloncle, Peter Radermacher, Pierre AsfarSeptic shock is defined by a complex associ Ebook Evidence based practice of critical care (2/E): Part 2iation of cardiovascular dysfunction: decreased systemic vascular resistance, hypovolemia, impaired microcirculation, and depressed myocardial function.1 This vascular impairment leads to an imbalance between oxygen delivery and demand. Thus, the aim of initial septic shock management is to rebalanc Ebook Evidence based practice of critical care (2/E): Part 2e this mismatch. Mean arterial pressure (MAP) is one of the hemodynamic targets used to try to ensure that organs are adequately perfused.2 During iniEbook Evidence based practice of critical care (2/E): Part 2
tial resuscitation, a MAP level of greater than 65 mm Hg is recommended in the Surviving Sepsis Campaign guidelines (grade 1C: high-grade recommendati40What MAP Objectives Should Be Targeted in Septic Shock?Francois Beloncle, Peter Radermacher, Pierre AsfarSeptic shock is defined by a complex associ Ebook Evidence based practice of critical care (2/E): Part 2any critically ill patients. However, intervention to achieve a higher MAP carries several risks. In septic shock, we must avoid three risks—underperfusion, tissue edema, and excessive vasoconstriction—that can lead to tissue hypoperfusion. The optimal MAP level (or the optimal vasopressor dose) cor Ebook Evidence based practice of critical care (2/E): Part 2responds to the optimal balance between these risks. The Surviving Sepsis Campaign guidelines suggest that the optimal MAP should lx- individualized bEbook Evidence based practice of critical care (2/E): Part 2
ecause it may be higher in selected patients such as those with atherosclerosis or previous hypertension.This review discusses the physiologic rationa40What MAP Objectives Should Be Targeted in Septic Shock?Francois Beloncle, Peter Radermacher, Pierre AsfarSeptic shock is defined by a complex associ Ebook Evidence based practice of critical care (2/E): Part 2tic shock resuscitation is to adapt oxygen (Oị) delivery to each organ's O2 demand. MAP is commonly considered as a surrogate of global perfusion pressure. Thus, increasing MAP level in septic shock patients might lead to an increase in Oj delivery to the tissue. However, a better understanding of a Ebook Evidence based practice of critical care (2/E): Part 2utoregula-tory mechanisms and microcirculation regulation during sepsis is needed to address this question. In addition, increasing MAP level impliesEbook Evidence based practice of critical care (2/E): Part 2
increasing vasopressor load, and this raises the question of the side effects of these agents.278AutoregulationAutoregulation refers to the ability of40What MAP Objectives Should Be Targeted in Septic Shock?Francois Beloncle, Peter Radermacher, Pierre AsfarSeptic shock is defined by a complex associ Ebook Evidence based practice of critical care (2/E): Part 2n zone."4 Below this autoregulation threshold, blood flow is directly dependent on perfusion pressure. Autoregulation is of particular importance in the brain? heart? and kidney - Of note, autoregulation threshold values vary in different organs.8 The kidney has the highest autoregulation threshold; Ebook Evidence based practice of critical care (2/E): Part 2 therefore it may be considered as the first resuscitation objective. Maintenance of a MAP within the renal autoregulatory range allows the organ to bEbook Evidence based practice of critical care (2/E): Part 2
e perfused in times of stress. Autoregulation thresholds differ in accordance with patients' age and associated comorbidities (e.g., chronic hypertens40What MAP Objectives Should Be Targeted in Septic Shock?Francois Beloncle, Peter Radermacher, Pierre AsfarSeptic shock is defined by a complex associ Ebook Evidence based practice of critical care (2/E): Part 2owle et al., renal blood flow assessed by cine phase-contrast magnetic resonance imaging was lower in septic patients than in control healthy patients despite a MAP between 70 and 100 mm Hg. These findings suggest that renal autoregulation is disturbed during sepsis.’1 However, in a rat model of sep Ebook Evidence based practice of critical care (2/E): Part 2sis, renal blood flow was altered over a large range of MAP. These findings support the conclusion that autoregulation may be conserved in sepsis.10 TEbook Evidence based practice of critical care (2/E): Part 2
hus, it is unknown whether autoregulation is maintained during sepsis and whether the autoregulation threshold is unchanged.It is worth noting that pe40What MAP Objectives Should Be Targeted in Septic Shock?Francois Beloncle, Peter Radermacher, Pierre AsfarSeptic shock is defined by a complex associ Ebook Evidence based practice of critical care (2/E): Part 2mated by the MAP) minus the organ venous pressure. The importance of the venous pressure has been shown in particular in the kidney.11MicrocirculationSepsis is associated with microcirculatory alterations characterized by increased endothelial permeability, leukocyte adhesion, and blood flow heterog Ebook Evidence based practice of critical care (2/E): Part 2eneity that can lead to tissue hypoxia.1 ' Microcirculatory blood flow may be largely independent of systemic hemodynamics.14 Consequently,Chapter 40Ebook Evidence based practice of critical care (2/E): Part 2
What MAP Objectives Should Be Targereo in ữepnc SHOCK.' z/ywhen systemic hemodynamic objectives (in particular .MAP target) are achieved, microcircula40What MAP Objectives Should Be Targeted in Septic Shock?Francois Beloncle, Peter Radermacher, Pierre AsfarSeptic shock is defined by a complex associ Ebook Evidence based practice of critical care (2/E): Part 2ration in the early phase of sepsis reflects a low perfusion pressure (i.e., a failure to achieve macrocirculation parameter targets at the beginning of the shock). Thus, although adjusting hemodynamic objectives at the second phase of the septic shock when patients are "hemodynamically stable" is u Ebook Evidence based practice of critical care (2/E): Part 2nlikely to improve microcirculation impairment, an early intervention with high MAP levels may prevent microcirculation dysfunction.Specific Effect ofEbook Evidence based practice of critical care (2/E): Part 2
High Vasopressor LoadIncreasing the MAP target to high levels may require high doses of vasopressor or inotropic drugs. Norepinephrine is the most co40What MAP Objectives Should Be Targeted in Septic Shock?Francois Beloncle, Peter Radermacher, Pierre AsfarSeptic shock is defined by a complex associ Ebook Evidence based practice of critical care (2/E): Part 2ascular resistance (and thus left ventricle afterload), norepinephrine usually slightly increases cardiac output because of its fl-adrenergic stimulation and its effect on venous return.1' The venous effect of norepinephrine might also affect the perfusion pressure.1’ In addition to the consequences Ebook Evidence based practice of critical care (2/E): Part 2 of excessive vasoconstriction, other effects should be taken into account when addressing the question of optimal vasopressor load. Sympathetic over-Ebook Evidence based practice of critical care (2/E): Part 2
stimulation (or adrenergic stress) may be associated with harmful effects such as diastolic dysfunction; tachyarrythmia; skeletal muscle damage (apopt40What MAP Objectives Should Be Targeted in Septic Shock?Francois Beloncle, Peter Radermacher, Pierre AsfarSeptic shock is defined by a complex associ Ebook Evidence based practice of critical care (2/E): Part 2ave examined optimal MAP targets in patients with sepsis. Two retrospective studies used MAP recordings and examined the time spent below different threshold values of MAP during early sepsis. Data were correlated with survival and organ dysfunction. In 111 patients with septic shock, Varpula et al. Ebook Evidence based practice of critical care (2/E): Part 2' showed that the mean MAP for the first 6 and 48 hours predicted 30-day outcome. With the use of receiver operator characteristic (ROC) curves, the bEbook Evidence based practice of critical care (2/E): Part 2
est predictive MAP threshold level for30-day mortality was 65 mm Hg. In addition, the time spent under this value also correlated with mortality. Howe40What MAP Objectives Should Be Targeted in Septic Shock?Francois Beloncle, Peter Radermacher, Pierre AsfarSeptic shock is defined by a complex associ Ebook Evidence based practice of critical care (2/E): Part 2imilar analysis in 274 sepsis or septic shock patients, but they adjusted for disease severity (as assessed by the Simplified Acute Physiology Score ịSAPSI II excluding systolic arterial pressure). The authors assessed the association between different arterial blood pressure levels during the first Ebook Evidence based practice of critical care (2/E): Part 2 24 hours after intensive care unit (1CU) admission and 28-day mortality or organ function. A 28-day mortality did not correlate with MAP drops belowEbook Evidence based practice of critical care (2/E): Part 2
60,6Ố, 70, and 75 mm Hg. However, an hourly time MAP integral that dropped below 55 mm Hg was associated with a significant decrease in the area under40What MAP Objectives Should Be Targeted in Septic Shock?Francois Beloncle, Peter Radermacher, Pierre AsfarSeptic shock is defined by a complex associ Ebook Evidence based practice of critical care (2/E): Part 2eed for renal replacement therapy was best predicted by the ROC curve for the hourly time integral of MAP drops below 75 mm Hg. Thus, a higher MAP level may be required to prevent acute kidney injury (AKI).In a post hoc analysis of data from a study investigating the effects on mortality of L-NMMA ( Ebook Evidence based practice of critical care (2/E): Part 2N-methyl-L-arginine), a nitric oxide inhibitor, there was no association between MAP (or MAP quartiles) and mortality or occurrence of disease-relatedEbook Evidence based practice of critical care (2/E): Part 2
events in a control group that included 290 septic shock patients.'"’ This study used logistic regression models and adjusted for age, the presence o40What MAP Objectives Should Be Targeted in Septic Shock?Francois Beloncle, Peter Radermacher, Pierre AsfarSeptic shock is defined by a complex associ Ebook Evidence based practice of critical care (2/E): Part 2ertension did not modify the association between MAP and 28-day mortality or AKI. In addition, the mean vasopressor load correlated with mortality and the number of disease-related events. The authors concluded that "MAP levels of 70 mm Hg or higher do not appear to be associated with improved survi Ebook Evidence based practice of critical care (2/E): Part 2val in septic shock" and that "elevating MAP >70 mm Hg by augmenting vasopressor dosages may increase mortality."In 217 patients with shock (127 or 59Ebook Evidence based practice of critical care (2/E): Part 2
% of whom had septic shock), enrolled and followed prospectively, Badin et al.21 showed that a low MAP averaged over 6 hours or 12 to 24 hours was assGọi ngay
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