Principles of fluid management and stewardship in septic shock: it is time to consider the four D's and the four phases of fluid therapy

In patients with septic shock, the administration of fluids during initial hemodynamic resuscitation remains a major therapeutic challenge. We are faced with many open questions regarding the type, dose and timing of intravenous fluid administration. There are only four major indications for intravenous fluid administration: aside from resuscitation, intravenous fluids have many other uses including maintenance and replacement of total body water and electrolytes, as carriers for medications and for parenteral nutrition. In this paradigm-shifting review, we discuss different fluid management strategies including early adequate goal-directed fluid management, late conservative fluid management and late goal-directed fluid removal. In addition, we expand on the concept of the “four D’s” of fluid therapy, namely drug, dosing, duration and de-escalation. During the treatment of patients with septic shock, four phases of fluid therapy should be considered in order to provide answers to four basic questions. These four phases are the resuscitation phase, the optimization phase, the stabilization phase and the evacuation phase. The four questions are “When to start intravenous fluids?”, “When to stop intravenous fluids?”, “When to start de-resuscitation or active fluid removal?” and finally “When to stop de-resuscitation?” In analogy to the way we handle antibiotics in critically ill patients, it is time for fluid stewardship.

Intestinal histopathological changes in a porcine model of pneumoperitoneum-induced intra-abdominal hypertension

BACKGROUND

Low splanchnic perfusion is an immediate effect of pneumoperitoneum-induced intra-abdominal hypertension (IAH). Anatomical structure results in the intestinal mucosa being the area most sensitive to hypoperfusion. The relationship between intestinal injury and clinical parameters of tissue perfusion [abdominal perfusion pressure (APP), gastric intramucosal pH (pH_i) and lactic acid (Lc)] has not been previously studied. This study aimed to monitorize intestinal pathogenesis through sequential ileal biopsies and to measure APP, pH_i, and Lc levels at different pneumoperitoneum-induced intra-abdominal pressures (20, 30, and 40 mmHg) to evaluate the potential relationships between them.

MATERIALS AND METHODS

Fifty pigs were divided into four groups; a control group (C) and three experimental groups with different pneumoperitoneum-induced levels [20 mmHg (G20), 30 mmHg (G30), and 40 mmHg (G40)], that were maintained for 3 and 5 h. APP, pH_i, and Lc were measured and ileal biopsies taken laparoscopically every 30 min. The mucosal damage was graded using the standardized Park's Score and animals were classified as injured (I+) or uninjured (I-).

RESULTS

Different histopathological lesions were observed in groups G20, G30, and G40 but no damage observed in group C. A 33.3% of animals in G20 and G30 were I+ after 3 h, while 93.3% were injured in G40. After 5 h, histopathological lesions were no longer seen in some animals in G20 and only 10% were I+. Conversely, in G30 I+ pigs increased to 80% while those in G40 remained at 93.3% I+. The I+ animals had significantly lower APP and pH_i than those I-. Lc was the clinical parameter that showed the earliest differences, with significantly higher figures in I+ animals.

CONCLUSIONS

The evolution of intestinal injuries from pneumoperitoneum-induced IAH depends on the degree of IAP. These damages may be associated with decreases in APP and pH_i, and increases in Lc.

Does the use of indirect calorimetry change outcome in the ICU? Yes it does

PURPOSE OF REVIEW

To review the recent findings on metabolic monitoring and possible beneficial effects of an adequate nutrition therapy, based on indirect calorimetry as the golden standard to predict energy expenditure.

RECENT FINDINGS

in the last decades, major steps are taken in the field of metabolism and nutrition, evolving from nutrition as a baseline support to a therapeutic intervention. The aspect of energy expenditure is of cardinal importance, and technical possibilities have impressively improved: from the first 'calorimetre' in 1789 to the new generation, clinical applicable indirect calorimeters and the high accuracy and easy use model reaching high technology readiness level [Oshima et al. (2017). Clin Nutr 36:651]. Several recent studies provide information on the technique of metabolic monitoring itself and the positive effects of implementation of the tool in a high-end nutritional care plan [Oshima et al. (2017). Clin Nutr 36:651]. The combination of correct energy provision and protein prescription has shown benefits, and mortality of ICU patients is related to the amount of energy provided [Zusman et al. (2016). Crit Care 20:367]. The use of a monitor per se will not change outcome. Optimal dosing of artificial nutrition can be achieved by the use of a parameter acquired by a measurement instead of by inaccurate equations. In the era of precision medicine, this approach has shown positive effects on outcome. Moreover, above all, the concept of metabolic monitoring of the critically ill is just an issue of common sense.

SUMMARY

Metabolic monitoring by indirect calorimetry is achieving a level in which it can be implemented in critical care practice. Evidence is available to prove that by guiding your nutritional therapy by measured values, it will change outcome of critically ill patients.

Point-of-care gastrointestinal and urinary tract sonography in daily evaluation of gastrointestinal dysfunction in critically ill patients (GUTS Protocol)

There is currently a lack of universally accepted criteria for gastrointestinal (GI) failure or dysfunction in critical care. Moreover, the clinical assessment of intestinal function is notoriously difficult and thus often goes unrecognized, contributing to poor outcomes. A recent grading system has been proposed to define acute gastrointestinal injury (AGI) in conjunction with other organ function scores (e.g., SOFA). Ultrasonography has become widely accepted as a diagnostic tool for GI problems and pathology. We propose a sonographic examination of the abdomen, using the GUTS protocol (gastrointestinal and urinary tract sonography) in critically ill patients as part of the point-of-care ultrasound evaluation in patients with AGI. This article reviews possible applications of ultrasonography that may be relevant to monitor the GI function in critically ill patients. The GI ultrasound protocol (GUTS) focuses on four gastrointestinal endpoints: gastrointestinal diameter, mucosal thickness, peristalsis, and blood flow. Moreover, it is possible to examine the urinary tract and kidney function. Real-time ultrasound with the GUTS protocol is a simple, inexpensive, bedside imaging technique that can provide anatomical and functional information of the GI tract. Further studies are needed to investigate the utility of GUTS with other parameters, such as GI biomarkers, AGI class, and clinical outcomes.

Executive summary on the use of ultrasound in the critically ill: consensus report from the 3rd Course on Acute Care Ultrasound (CACU)

Over the past decades, ultrasound (US) has gained its place in the armamentarium of monitoring tools in the intensive care unit (ICU). Critical care ultrasonography (CCUS) is the combination of general CCUS (lung and pleural, abdominal, vascular) and CC echocardiography, allowing prompt assessment and diagnosis in combination with vascular access and therapeutic intervention. This review summarises the findings, challenges lessons from the 3rd Course on Acute Care Ultrasound (CACU) held in November 2015, Antwerp, Belgium. It covers the different modalities of CCUS; touching on the various aspects of training, clinical benefits and potential benefits. Despite the benefits of CCUS, numerous challenges remain, including the delivery of CCUS training to future intensivists. Some of these are discussed along with potential solutions from a number of national European professional societies. There is a need for an international agreed consensus on what modalities are necessary and how best to deliver training in CCUS.

The role of point-of-care ultrasound in intra-abdominal hypertension management

BACKGROUND

Intra-abdominal hypertension is a common complication in critically ill patients. Recently the Abdominal Compartment Society (WSACS) developed a medical management algorithm with a stepwise approach according to the evolution of the intra-abdominal pressure and aiming to keep IAP ≤ 15 mm Hg. With the increased use of ultrasound as a bedside modality in both emergency and critical care patients, we hypothesized that ultrasound could be used as an adjuvant point-of-care tool during IAH management. This may be particularly relevant to the first and second basic stages of the algorithm. The objective of this paper is to test the use of POCUS as an adjuvant tool in the management of patients with IAH/ACS.

METHODS

Seventy-three consecutive adult critically ill patients admitted to the surgical intensive care unit (ICU) of a single urban institution with risk factor for IAH/ACS were enrolled. Those who met the inclusion criteria were allocated to undergo POCUS as an adjuvant tool in their IAH/ACS management.

RESULTS

A total of 50 patients met the inclusion criteria and were included in the study. The mean age of study participants was 55 ± 22.6 years, 58% were men, and the most frequent admission diagnosis was post-operative care following abdominal intervention. All admitted patients presented with a degree of IAH during their ICU stay. Following step 1 of the WSACS IAH medical management algorithm, ultrasound was used for NGT placement, confirmation of correct positioning, and evaluation of stomach contents. Ultrasound was comparable to abdominal X-ray, but shown to be superior in determining the gastric content (fluid vs. solid). Furthermore, POCUS allowed faster determination of correct NGT positioning in the stomach (antrum), avoiding bedside radiation exposure. Ultrasound also proved useful in: 1) evaluation of bowel activity; 2) identification of large bowel contents; 3) identification of patients that would benefit from bowel evacuation (enema) as an adjuvant to lower IAP; 4) and in the diagnosis of moderate to large amounts of free intra-abdominal fluid.

CONCLUSION

POCUS is a powerful systematic ultrasound technique that can be used as an adjuvant in intra-abdominal hypertension management. It has the potential to be used in both diagnosis and treatment during the course of IAH.

Cardiac ultrasound: a true haemodynamic monitor?

Cardiac ultrasound has been used in the critically ill for more than thirty years. The technology has made enormous progression with respect to image quality and quantity, various Doppler techniques, as well as connectivity, the transfer of data and offline calculations. Some consider cardiac ultrasound as the stethoscope of the Twenty-first century. The potential of eye-balling moving cardiac structures gives undeniable power to this diagnostic and monitoring tool. The main shortcoming is the discontinuous mode of monitoring and the fact that optimal information acquisition can only be obtained when one is well-trained and experienced. Cardiac ultrasound has become an indispensable tool, especially in haemodynamically unstable patients. This review summarizes some important aspects of cardiac ultrasound with use of Doppler monitoring for assessment of the three most important pillars of haemodynamics, namely cardiac preload, afterload and contractile function.

Re-operative abdominal predictive score: a prognostic model combining Acute Re-intervention Predictive Index and intra-abdominal pressure

BACKGROUND

The decision to re-operate after abdominal surgery is still difficult, especially in the setting of intraabdominal sepsis. Mathematical models provide a good aid to both diagnosis and decision-making.

METHODS

A prospective observational study was conducted with 300 patients consecutively admitted to the intensive care unit of an academic institution affiliated to Calixto García Medical Faculty following abdominal surgery from January 2008 to January 2010. The patients were randomly separated (2:1) into estimation and validation groups. Logistic regression analysis was used in the estimation group to develop three models for decision-making related to re-operation including related factors such as age, ARPI, IAP, type of surgery (elective or emergency), and the duration of surgery. The three models developed were validated on the other group.

RESULTS

The acute re-operation predictive index-intra-abdominal pressure (ARPI-IAP) model was the best of the three models, with an excellent calibration, using the Hossmer-Lemeshow goodness-of-fit statistical test (C = 9.976, P = 0.267), as well as discrimination (AUC = 0.989; 95% CI: 0.976-1.000).

CONCLUSION

The combination of IAP with ARPI in a mathematical model can add accuracy to the prediction of need for re-operation related to intra-abdominal infectious complications in patients following abdominal surgery. This may be useful in all medical settings, but especially those with limited resources.

The use of crystalloids in traumatic brain injury

Fluid therapy is one of the most important treatments in patients with traumatic brain injury (TBI) as both hypo- and hypervolaemia can cause harm. The main goals of fluid therapy for patients with TBI are to optimize cerebral perfusion and to maintain adequate cerebral oxygenation. The avoidance of cerebral oedema is clearly essential. The current weight of evidence in the published literature suggests that albumin therapy is harmful and plasma substitutes have failed to demonstrate superiority over crystalloids solutions. Crystalloids are the most common fluids administered in patients with TBI. However, differences in their composition may affect coagulation and plasma tonicity and acid-base homeostasis. The choice of the ideal crystalloid fluid in TBI should be made based on tonicity, type of buffer used and volume status. Hypotonic fluids buffered with substances altering blood coagulation should be avoided in clinical practice. The prescriber remains faced with choices about the tonicity and pH buffering capability of fluid therapy, which we review here.

Perioperative gastrointestinal problems in the ICU

Gastrointestinal (GI) problems after surgery are common and are not limited to patients undergoing abdominal surgery. GI function is complicated to monitor and is not included in organ dysfunction scores widely used in the ICUs. In most cases, it recovers after surgery, if systemic and local inflammation and perfusion improve, gut oedema resolves, and analgosedation is reduced. However, perioperative GI problems may have severe consequences and increase the risk of death if not recognized and managed in a timely manner. Careful risk evaluation followed by a complex structured assessment and appropriate management of GI symptoms should minimize the potentially severe consequences and thereby possibly improve outcome. In the current review, we summarize common non-specific perioperative GI problems and some specific surgery-related abdominal problems, address identification of patients at risk of GI problems, and give suggestions for perioperative GI management.

The black box revelation: monitoring gastrointestinal function

The gastrointestinal tract comprises diverse functions. Despite recent developments in technology and science, there is no single and universal tool to monitor GI function in intensive care unit (ICU) patients. Clinical evaluation is complex and has a low sensitivity to diagnose pathological processes in the abdomen. We performed a MEDLINE and Pubmed search connecting abdominal assessment and critical care. Based on these findings we defined the following major categories of monitoring and diagnostic measures: clinical investigation; assessment of motility and digestive function; microbiome monitoring; perfusion monitoring; laboratory biomarkers and hormonal function; intra-abdominal pressure measurement; and imaging techniques. Only a few of these monitoring and assessment tools have found their way into clinical practice, as most of them have one or more significant objections preventing broad implementation in daily clinical practice. Further research should be directed to reaffirm and define the use of current techniques to ascertain their validity and usefulness to monitor gastrointestinal function in ICU patients.

Lung ultrasound in the critically ill (LUCI): A translational discipline

In the early days of ultrasound, it was not a translational discipline. The heart was claimed by cardiologists, with others, such as gynaecologists, urologists and vascular surgeons claiming their part while the rest was given to radiologists. Only recently, ultrasound transgressed and crossed the usual borders between the different disciplines, such as emergency and critical care medicine. The advent of portable machines in the early 1980s, allowed the critical care physician to perform bedside ultrasound, and the development of whole body critical care ultrasound (CCUS) was born. It may sound cynical that radiologists were the first to state that diagnostic sonography was truly the next stethoscope: poorly utilized by many but understood by few. Exactly the same radiologists then abandoned the use of ultrasound outside the radiology department, leaving a vast domain to other disciplines eager to welcome the modern stethoscope. In this review, we list the possibilities of lung ultrasound as a translational holistic discipline.

Intravenous fluid therapy for hospitalized and critically ill children: rationale, available drugs and possible side effects

Human beings are constituted mainly of water. In particular, children's total body water might reach 75-80% of their body weight, compared to 60-70% in adults. It is therefore not surprising, that children, especially hospitalized newborns and infants, are markedly prone to water and electrolyte imbalances. Parenteral fluid therapy is a cornerstone of medical treatment and is thus of exceptional relevance in this patient population. It is crucial to appreciate the fact that intravenous fluids are drugs with very different characteristics, different indications, contraindications and relevant side effects. In the present review, we will summarize the physiology and pathophysiology of water and electrolyte balance, underlining the importance and high prevalence of non-osmotic antidiuretic hormone release in hospitalized and critically ill children. Furthermore, we will discuss the characteristics and potential side effects of available crystalloids for the paediatric population, making a clear distinction between fluids that are hypotonic or isotonic as compared to normal plasma. Finally, we will review the current clinical practice regarding the use of different parenteral fluids in children, outlining both the current consensus on fluids employed for resuscitation and replacement and the ongoing debate concerning parenteral maintenance fluids.

Abdominal pressure and gastrointestinal function: an inseparable couple?

Evaluating the degree of organ dysfunction is a cornerstone in distinguishing patients with critical illness from those without. However, evaluation of the gastrointestinal function in critically ill patients is not unified, and is still largely based on subjective clinical evaluation. Although intra-abdominal pressure has been proposed as a parameter to facilitate monitoring of abdominal compartment in critical illness, the interactions between intra-abdominal pressure and gastrointestinal function are poorly clarified. The aim of this current review is to describe interactions and associations between gastrointestinal dysfunction and intra-abdominal pressure from a pathophysiological and clinical point of view.

Early impact of abdominal compartment syndrome on liver, kidney and lung damage in a rodent model

BACKGROUND

Abdominal compartment syndrome (ACS) sometimes occurs in critically ill patients following damage control surgery. The purpose of the present study was to develop a model of ACS and to evaluate its pathologic impact on liver, kidney, and lung morphology.

METHODS

Twenty Wistar rats (mass 300-350 g) were randomly divided into four groups: 1) intra-abdominal hypertension (IAH): a laparotomy was performed and the abdomen packed with cotton until an intra-abdominal pressure (IAP) of 15 mm Hg was reached; 2) hypovolemia (HYPO): blood was withdrawn until a mean arterial pressure ~60 mm Hg was reached; 3) IAH + HYPO (to resemble clinical ACS); and 4) sham surgery. After 3 hours of protective mechanical ventilation, the animals were euthanized and the liver, kidney and lungs removed to examine the degree of tissue damage.

RESULTS

IAH resulted in the following: oedema and neutrophil infiltration in the kidney; necrosis, congestion, and microsteatosis in the liver; and alveolar collapse, haemorrhage, interstitial oedema, and neutrophil infiltration in the lungs. Furthermore, IAH was associated with greater cell apoptosis in the kidney, liver and lungs compared to sham surgery. HYPO led to oedema and neutrophil infiltration in the kidney. The combination of IAH and HYPO resulted in all the aforementioned changes in lung, kidney and liver tissue, as well as exacerbation of the inflammatory process in the kidney and liver and kidney cell necrosis and apoptosis.

CONCLUSIONS

Intra-abdominal hypertension by itself is associated with kidney, liver and lung damage; when combined with hypovolemia, it leads to further impairment and organ damage.

Acute kidney injury in the ICU: from injury to recovery: reports from the 5th Paris International Conference

The French Intensive Care Society organized its yearly Paris International Conference in intensive care on June 18-19, 2015. The main purpose of this meeting is to gather the best experts in the field in order to provide the highest quality update on a chosen topic. In 2015, the selected theme was: "Acute Renal Failure in the ICU: from injury to recovery." The conference program covered multiple aspects of renal failure, including epidemiology, diagnosis, treatment and kidney support system, prognosis and recovery together with acute renal failure in specific settings. The present report provides a summary of every presentation including the key message and references and is structured in eight sections: (a) diagnosis and evaluation, (b) old and new diagnosis tools,

Acute kidney injury in the ICU: from injury to recovery: reports from the 5th Paris International Conference

The French Intensive Care Society organized its yearly Paris International Conference in intensive care on June 18-19, 2015. The main purpose of this meeting is to gather the best experts in the field in order to provide the highest quality update on a chosen topic. In 2015, the selected theme was: "Acute Renal Failure in the ICU: from injury to recovery." The conference program covered multiple aspects of renal failure, including epidemiology, diagnosis, treatment and kidney support system, prognosis and recovery together with acute renal failure in specific settings. The present report provides a summary of every presentation including the key message and references and is structured in eight sections: (a) diagnosis and evaluation, (b) old and new diagnosis tools,

Early enteral nutrition in critically ill patients: ESICM clinical practice guidelines

Purpose

To provide evidence-based guidelines for early enteral nutrition (EEN) during critical illness.

Methods

We aimed to compare EEN vs. early parenteral nutrition (PN) and vs. delayed EN. We defined “early” EN as EN started within 48 h independent of type or amount. We listed, a priori, conditions in which EN is often delayed, and performed systematic reviews in 24 such subtopics. If sufficient evidence was available, we performed meta-analyses; if not, we qualitatively summarized the evidence and based our recommendations on expert opinion. We used the GRADE approach for guideline development. The final recommendations were compiled via Delphi rounds.

Results

We formulated 17 recommendations favouring initiation of EEN and seven recommendations favouring delaying EN. We performed five meta-analyses: in unselected critically ill patients, and specifically in traumatic brain injury, severe acute pancreatitis, gastrointestinal (GI) surgery and abdominal trauma. EEN reduced infectious complications in unselected critically ill patients, in patients with severe acute pancreatitis, and after GI surgery. We did not detect any evidence of superiority for early PN or delayed EN over EEN. All recommendations are weak because of the low quality of evidence, with several based only on expert opinion.

Conclusions

We suggest using EEN in the majority of critically ill under certain precautions. In the absence of evidence, we suggest delaying EN in critically ill patients with uncontrolled shock, uncontrolled hypoxaemia and acidosis, uncontrolled upper GI bleeding, gastric aspirate >500 ml/6 h, bowel ischaemia, bowel obstruction, abdominal compartment syndrome, and high-output fistula without distal feeding access.

Electronic supplementary material

The online version of this article (doi:10.1007/s00134-016-4665-0) contains supplementary material, which is available to authorized users.