The adrenocorticotropic hormone-induced cortisol response in acute pancreatitis

The evidence that severe acute pancreatitis can result in critical illness-related corticosteroid insufficiency following impaired adrenal secretion is accumulating. The study by Peng and coworkers in Critical Care certainly contributes to that idea, even though the question whether relative adrenal insufficiency should prompt for treatment by substitution doses of corticosteroids remains unresolved. The study is discussed in terms of the risk factors, circumstances and significance of impaired corticosteroid secretion by adrenals in severe acute pancreatitis

Acute lung injury, overhydration or both?

Acute lung injury or acute respiratory distress syndrome (ALI/ARDS) in the course of sepsis is thought to result from increased pulmonary capillary permeability and resultant edema. However, when the edema is assessed at the bedside by measuring the extravascular thermal volume by transpulmonary dilution, some ALI/ARDS patients with sepsis may have normal extravascular lung water (EVLW). Conversely, a raised EVLW may be present even when criteria for ALI/ARDS are not met, according to GS Martin and colleagues in this issue of Critical Care. This commentary puts the findings into a broader perspective and focuses on the difficulty, at the bedside, in recognizing and separating various types of pulmonary edema. Some of these forms of edema, classically differentiated on the basis of increased permeability and cardiogenic/hydrostatic factors, may overlap, whereas the criteria for ALI/ARDS may be loose, poorly reproducible, relatively insensitive and nonspecific, and highly therapy-dependent. Overhydration is particularly difficult to recognize. Additional diagnostics may be required to improve the delineation of pulmonary edema so as to redirect or redefine treatment and improve patient morbidity and, perhaps, mortality. Monitoring EVLW by single transpulmonary thermal dilution, for instance, might have a future role in this process

Hypothalamo-pituitary-adrenal axis activity after intracranial catastrophies: what is enough?

This commentary on a paper by Bendel and colleagues in the previous issue of Critical Care describes the difficulty in assessing the sufficiency of adrenal responses to endogenous, stress-induced adrenocorticotropic hormone (ACTH) release by the pituitary or to exogenous ACTH administration in the critically ill patient in general, and after subarachnoid hemorrhage in particular. It is argued that comparisons with responses under circumstances of equal stress as well as assessments of severity of disease are necessary to judge the sufficiency of cortisol responses to endogenous and exogenous ACTH before treatment is considered. There are no universally applicable cutoff values for cortisol levels – and increases in cortisol levels with increasing levels of ACTH – for the diagnosis of relative adrenal insufficiency (or as it is now commonly termed, critical illnes-related corticosteroid insufficiency) following, for example, subarachnoid hemorrhage or other intracranial catastrophes. The paper by Bendel and colleagues is critically discussed in view of these concepts

A plethora of angiopoietin-2 effects during clinical sepsis

The interesting study by Davis and colleagues in the current issue of Critical Care expands on the increasingly recognized role of angiopoietins in human sepsis but raises a number of questions, which are discussed in this commentary. The authors describe an association between elevated angiopoietin (ang)-2 levels and impaired vascular reactivity, measured by the partly nitric oxide-dependent finger hyperemic response to forearm vascular occlusion, in patients with sepsis. This suggests that the ang-1/2-Tie2 system is involved in a number of pathophysiologic, phenotypic and perhaps prognostic alterations in human sepsis, on top of the effect on pulmonary endothelial barrier function. The novel inflammatory route may be a target for future therapeutic studies in human sepsis and acute lung injury, including those with activated protein C

Dose and type of crystalloid fluid therapy in adult hospitalized patients

AbstractObjectiveIn this narrative review, an overview is given of the pros and cons of various crystalloid fluids used for infusion during initial resuscitation or maintenance phases in adult hospitalized patients. Special emphasis is given on dose, composition of fluids, presence of buffers (in balanced solutions) and electrolytes, according to recent literature. We also review the use of hypertonic solutions.MethodsWe extracted relevant clinical literature in English specifically examining patient-oriented outcomes related to fluid volume and type.ResultsA restrictive fluid therapy prevents complications seen with liberal, large-volume therapy, even though restrictive fluid loading with crystalloids may not demonstrate large hemodynamic effects in surgical or septic patients. Hypertonic solutions may serve the purpose of small volume resuscitation but carry the disadvantage of hypernatremia. Hypotonic solutions are contraindicated in (impending) cerebral edema, whereas hypertonic solutions are probably more helpful in ameliorating than in preventing this condition and improving outcome. Balanced solutions offer a better approach for plasma composition than unbalanced ones, and the evidence for benefits in patient morbidity and mortality is increasing, particularly by helping to prevent acute kidney injury.ConclusionsIsotonic and hypertonic crystalloid fluids are the fluids of choice for resuscitation from hypovolemia and shock. The evidence that balanced solutions are superior to unbalanced ones is increasing. Hypertonic saline is effective in mannitol-refractory intracranial hypertension, whereas hypotonic solutions are contraindicated in this condition.</jats:sec

Infections of respiratory or abdominal origin in ICU patients: what are the differences?

There are few data related to the effects of different sources of infection on outcome. We used the Sepsis Occurrence in Acutely ill Patients (SOAP) database to investigate differences in the impact of respiratory tract and abdominal sites of infection on organ failure and survival.Comparative StudyJournal ArticleMulticenter StudyResearch Support, Non-U.S. Gov'tSCOPUS: ar.jinfo:eu-repo/semantics/publishe

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

A prolonged run-in period of standard subcutaneous microdialysis ameliorates quality of interstitial glucose signal in patients after major cardiac surgery

We evaluated a standard subcutaneous microdialysis technique for glucose monitoring in two critically ill patient populations and tested whether a prolonged run-in period improves the quality of the interstitial glucose signal. 20 surgical patients after major cardiac surgery (APACHE II score: 10.1 ± 3.2) and 10 medical patients with severe sepsis (APACHE II score: 31.1 ± 4.3) were included in this investigation. A microdialysis catheter was inserted in the subcutaneous adipose tissue of the abdominal region. Interstitial fluid and arterial blood were sampled in hourly intervals to analyse glucose concentrations. Subcutaneous adipose tissue glucose was prospectively calibrated to reference arterial blood either at hour 1 or at hour 6. Median absolute relative difference of glucose (MARD), calibrated at hour 6 (6.2 (2.6; 12.4) %) versus hour 1 (9.9 (4.2; 17.9) %) after catheter insertion indicated a significant improvement in signal quality in patients after major cardiac surgery (p < 0.001). Prolonged run-in period revealed no significant improvement in patients with severe sepsis, but the number of extreme deviations from the blood plasma values could be reduced. Improved concurrence of glucose readings via a 6-hour run-in period could only be achieved in patients after major cardiac surgery