Effects of IV fluid restriction according to site-specific intensity of standard fluid treatment-protocol

BACKGROUND

Variation in usual practice in fluid trials assessing lower versus higher volumes may affect overall comparisons. To address this, we will evaluate the effects of heterogeneity in treatment intensity in the Conservative versus Liberal Approach to Fluid Therapy of Septic Shock in Intensive Care trial. This will reflect the effects of differences in site-specific intensities of standard fluid treatment due to local practice preferences while considering participant characteristics.

METHODS

We will assess the effects of heterogeneity in treatment intensity across one primary (all-cause mortality) and three secondary outcomes (serious adverse events or reactions, days alive without life support and days alive out of hospital) after 90 days. We will classify sites based on the site-specific intensity of standard fluid treatment, defined as the mean differences in observed versus predicted intravenous fluid volumes in the first 24 h in the standard-fluid group while accounting for differences in participant characteristics. Predictions will be made using a machine learning model including 22 baseline predictors using the extreme gradient boosting algorithm. Subsequently, sites will be grouped into fluid treatment intensity subgroups containing at least 100 participants each. Subgroups differences will be assessed using hierarchical Bayesian regression models with weakly informative priors. We will present the full posterior distributions of relative (risk ratios and ratios of means) and absolute differences (risk differences and mean differences) in each subgroup.

DISCUSSION

This study will provide data on the effects of heterogeneity in treatment intensity while accounting for patient characteristics in critically ill adult patients with septic shock.

REGISTRATIONS

The European Clinical Trials Database (EudraCT): 2018-000404-42, ClinicalTrials. gov: NCT03668236.

Consistency of data reporting in fluid responsiveness studies in the critically ill setting: the CODEFIRE consensus from the Cardiovascular Dynamic section of the European Society of Intensive Care Medicine

PURPOSE

To provide consensus recommendations regarding hemodynamic data reporting in studies investigating fluid responsiveness and fluid challenge (FC) use in the intensive care unit (ICU).

METHODS

The Executive Committee of the European Society of Intensive Care Medicine (ESICM) commissioned and supervised the project. A panel of 18 international experts and a methodologist identified main domains and items from a systematic literature, plus 2 ancillary domains. A three-step Delphi process based on an iterative approach was used to obtain the final consensus. In the Delphi 1 and 2, the items were selected with strong (≥ 80% of votes) or week agreement (70-80% of votes), while the Delphi 3 generated recommended (≥ 90% of votes) or suggested (80-90% of votes) items (RI and SI, respectively).

RESULTS

We identified 5 main domains initially including 117 items and the consensus finally resulted in 52 recommendations or suggestions: 18 RIs and 2 SIs statements were obtained for the domain "ICU admission", 11 RIs and 1 SI for the domain "mechanical ventilation", 5 RIs for the domain "reason for giving a FC", 8 RIs for the domain pre- and post-FC "hemodynamic data", and 7 RIs for the domain "pre-FC infused drugs". We had no consensus on the use of echocardiography, strong agreement regarding the volume (4 ml/kg) and the reference variable (cardiac output), while weak on administration rate (within 10 min) of FC in this setting.

CONCLUSION

This consensus found 5 main domains and provided 52 recommendations for data reporting in studies investigating fluid responsiveness in ICU patients.

Albumin use in patients with septic shock-Post-hoc analyses of an international randomised fluid trial

BACKGROUND

Albumin administration is suggested in patients with sepsis and septic shock who have received large volumes of crystalloids. Given lack of firm evidence, clinical practice variation may exist. To address this, we investigated if patient characteristics or trial site were associated with albumin use in septic shock.

METHODS

We conducted a post-hoc study of the CLASSIC international, randomised clinical trial of fluid volumes in septic shock. Associations between selected baseline variables and trial site with albumin use during ICU stay were assessed in Cox models considering death, ICU discharge, and loss-to-follow-up as competing events. Baseline variables were first assessed individually, adjusted for treatment allocation (restrictive vs. standard IV fluid), and then adjusted for allocation and the other baseline variables. Site was assessed in a model adjusted for allocation and baseline variables.

RESULTS

We analysed 1541 of 1554 patients randomised in CLASSIC (99.2%). During ICU stay, 36.3% of patients in the restrictive-fluid group and 52.6% in the standard-fluid group received albumin. Gastrointestinal focus of infection and higher doses of norepinephrine were most strongly associated with albumin use (subgroup with highest quartile of norepinephrine doses, hazard ratio (HR) 2.58, 95% CI 1.89 to 3.53). HRs for associations between site and albumin use ranged from 0.11 (95% CI 0.05 to 0.26) to 1.70 (95% CI 1.06 to 2.74); test for overall effect of site: p < .001.

CONCLUSIONS

In adults with septic shock, gastrointestinal focus of infection and higher doses of norepinephrine at baseline were associated with albumin use, which also varied substantially between sites.

Restrictive versus standard IV fluid therapy in adult ICU patients with septic shock-Bayesian analyses of the CLASSIC trial

BACKGROUND

The CLASSIC trial assessed the effects of restrictive versus standard intravenous (IV) fluid therapy in adult intensive care unit (ICU) patients with septic shock. This pre-planned study provides a probabilistic interpretation and evaluates heterogeneity in treatment effects (HTE).

METHODS

We analysed mortality, serious adverse events (SAEs), serious adverse reactions (SARs) and days alive without life-support within 90 days using Bayesian models with weakly informative priors. HTE on mortality was assessed according to five baseline variables: disease severity, vasopressor dose, lactate levels, creatinine values and IV fluid volumes given before randomisation.

RESULTS

The absolute difference in mortality was 0.2%-points (95% credible interval: -5.0 to 5.4; 47% posterior probability of benefit [risk difference <0.0%-points]) with restrictive IV fluid. The posterior probabilities of benefits with restrictive IV fluid were 72% for SAEs, 52% for SARs and 61% for days alive without life-support. The posterior probabilities of no clinically important differences (absolute risk difference ≤2%-points) between the groups were 56% for mortality, 49% for SAEs, 90% for SARs and 38% for days alive without life-support. There was 97% probability of HTE for previous IV fluid volumes analysed continuously, that is, potentially relatively lower mortality of restrictive IV fluids with higher previous IV fluids. No substantial evidence of HTE was found in the other analyses.

CONCLUSION

We could not rule out clinically important effects of restrictive IV fluid therapy on mortality, SAEs or days alive without life-support, but substantial effects on SARs were unlikely. IV fluids given before randomisation might interact with IV fluid strategy.

Modulation of the capillary leakage by exogenous albumin in a rat model of endothelial glycocalyx damage

BACKGROUND

Endothelial glycocalyx (EG) plays a crucial role in maintaining the plasma proteins within the intravascular space.

OBJECTIVE

We studied whether exogenous albumin protects the EG in an experimental model of EG enzymatic damage in rats.

METHODS

Rats were divided into three groups of 10 animals that received (1) Evans blue (2) Evans blue + hyaluronidase, or (3) Evans blue + hyaluronidase + 20% human albumin via the tail vein. Spectrophotometric analysis was performed 2 h later to quantify the leakage of Evans blue-labeled albumin into the heart, lungs, brain, kidneys, liver, small intestine, spleen, and skeletal muscle.

RESULTS

Administration of hyaluronidase numerically increased the capillary leakage of Evans blue in all examined tissues. Co-administration of albumin decreased the leakage of albumin in all tissues except the heart. In the lungs, the ratio between the absorbance and dry organ weight decreased from 5.3 ± 2.4 to 1.7 ± 0.5 (mean ± SD) (P < 0.002), and in the liver, the absorbance decreased from 2.2 ± 0.7 to 1.5 ± 0.4 (P < 0.011).

CONCLUSION

Exogenous albumin decreased the capillary leakage of albumin which was interpreted as a sign of maintained EG integrity.

Comparison of Bioelectrical Impedance Analysis (BIA)-Derived Parameters in Healthy Volunteers and Critically Ill Patients

OBJECTIVE

To compare bioelectrical impedance analysis (BIA)-derived parameters in healthy volunteers and critically ill patients and to assess its prognostic value in an ICU patient cohort.

DESIGN

Retrospective, observational data analysis.

SETTING

Single centre, tertiary-level ICU (Ziekenhuis Netwerk Antwerpen, ZNA Stuivenberg Hospital).

PATIENTS

101 patients and 101 healthy subjects, participants of International Fluid Academy Days.

MEASUREMENTS AND MAIN RESULTS

Compared to healthy volunteers, both male and female ICU patients had significantly higher values for total body water (TBW), extracellular water (ECW), extracellular fluid (ECF), plasma, and interstitial fluid volumes. The phase angle was significantly lower and the malnutrition index was significantly higher in ICU patients, regardless of gender. Non-survivors in the ICU had significantly higher extracellular water content (ECW, 50.7 ± 5.1 vs. 48.9 ± 4.3%, p = 0.047) and accordingly significantly lower intracellular water (ICW, 49.2 ± 5.1 vs. 51.1 ± 4.3%, p = 0.047). The malnutrition index was also significantly higher in non-survivors compared to survivors (0.94 ± 0.17 vs. 0.87 ± 0.16, p = 0.048), as was the capillary leak index (ECW/ICW).

CONCLUSIONS

Compared to healthy volunteers, this study observed a higher malnutrition index and TBW in ICU patients with an accumulation of fluids in the extracellular compartment. ICU non-survivors showed similar results, indicating that ICU patients and a fortiori non-survivors are generally overhydrated, with increased TBW and ECW, and more undernourished, as indicated by a higher malnutrition index.

Core competencies in critical care for general medical practitioners in South Africa: A Delphi study

Background

Despite a high burden of disease that requires critical care services, there are a limited number of intensivists in South Africa (SA). Medical practitioners at district and regional public sector hospitals frequently manage critically ill patients in the absence of intensivists, despite these medical practitioners having had minimal exposure to critical care during their undergraduate training.

Objectives

To identify core competencies in critical care for medical practitioners who provide critical care services at public sector hospitals in SA where intensivists are not available to direct patient management.

Methods

A preliminary list of core competencies in critical care was compiled. Thereafter, 13 national and international experts were requested to achieve consensus on a final list of core competencies that are required for critical care by medical practitioners, using a modified Delphi process.

Results

A final list of 153 core competencies in critical care was identified.

Conclusion

The core competencies identified by this study could assist in developing training programmes for medical practitioners to improve the quality of critical care services provided at district and regional hospitals in SA.

Contribution of the study

The study provides consensus on a list of core competencies in critical care that non-intensivist medical practitioners managing critically ill patients in healthcare settings in South Africa, especially where intensivists are not readily available, should have. The list can form the core content of training programmes aimed at improving critical care competence of general medical practitioners, and in this way hopefully improve the overall outcomes of critically ill patients in South Africa.

A survey of preferences for respiratory support in the intensive care unit for patients with acute hypoxaemic respiratory failure

BACKGROUND

When caring for mechanically ventilated adults with acute hypoxaemic respiratory failure (AHRF), clinicians are faced with an uncertain choice between ventilator modes allowing for spontaneous breaths or ventilation fully controlled by the ventilator. The preferences of clinicians managing such patients, and what motivates their choice of ventilator mode, are largely unknown. To better understand how clinicians' preferences may impact the choice of ventilatory support for patients with AHRF, we issued a survey to an international network of intensive care unit (ICU) researchers.

METHODS

We distributed an online survey with 32 broadly similar and interlinked questions on how clinicians prioritise spontaneous or controlled ventilation in invasively ventilated patients with AHRF of different severity, and which factors determine their choice.

RESULTS

The survey was distributed to 1337 recipients in 12 countries. Of these, 415 (31%) completed the survey either fully (52%) or partially (48%). Most respondents were identified as medical specialists (87%) or physicians in training (11%). Modes allowing for spontaneous ventilation were considered preferable in mild AHRF, with controlled ventilation considered as progressively more important in moderate and severe AHRF. Among respondents there was strong support (90%) for a randomised clinical trial comparing spontaneous with controlled ventilation in patients with moderate AHRF.

CONCLUSIONS

The responses from this international survey suggest that there is clinical equipoise for the preferred ventilator mode in patients with AHRF of moderate severity. We found strong support for a randomised trial comparing modes of ventilation in patients with moderate AHRF.

Evaluation of the TraumaGuard Balloon-in-Balloon Catheter Design for Intra-Abdominal Pressure Monitoring: Insights from Pig and Human Cadaver Studies

Introduction: Intra-abdominal pressure (IAP) monitoring is crucial for the detection and prevention of intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS). In the 1970s, air-filled catheters (AFCs) for urodynamic studies were introduced as a solution to overcome the limitations of water-perfused catheters. Recent studies have shown that for correct IAP measurement with traditional AFC, the bladder needs to be primed with 25 mL of saline solution to allow pressure wave transmission to the transducer outside of the body, which limits continuous IAP monitoring. Methods: In this study, a novel triple balloon, air-filled TraumaGuard (TG) catheter system from Sentinel Medical Technologies (Jacksonville, FL, USA) with a unique balloon-in-balloon design was evaluated in a porcine and cadaver model of IAH via laparoscopy (IAPgold). Results: In total, 27 and 86 paired IAP measurements were performed in two pigs and one human cadaver, respectively. The mean IAPTG was 20.7 ± 10.7 mmHg compared to IAPgold of 20.3 ± 10.3 mmHg in the porcine study. In the cadaver investigation, the mean IAPTG was 15.6 ± 10.8 mmHg compared to IAPgold of 14.4 ± 10.4 mmHg. The correlation, concordance, bias, precision, limits of agreement, and percentage error were all in accordance with the WSACS (Abdominal Compartment Society) recommendations and guidelines for research. Conclusions: These findings support the use of the TG catheter for continuous IAP monitoring, providing early detection of elevated IAP, thus enabling the potential for prevention of IAH and ACS. Confirmation studies with the TraumaGuard system in critically ill patients are warranted to further validate these findings.

Early detection of oliguric events in critically ill patients in the ICU with a novel continuous urine flow measurement device: results of an initial validation study

OBJECTIVES

Urine output is used to evaluate fluid status and is an important marker for acute kidney injury (AKI). Our primary aim was to validate a new automatic urine output monitoring device by comparison to the current practice - the standard urometer.

METHODS

We conducted a prospective observational study in three ICUs. Urine flow measurements by Serenno Medical Automatic urine output measuring device (Serenno Medical, Yokneam, Israel) were compared to standard urometer readings taken automatically at 5-minutes intervals by a camera, and to hourly urometer readings by the nurses, both over 1 to 7 days. Our primary outcome was the difference between urine flow assessed by the Serenno device and reference camera-derived measurements (Camera). Our secondary outcome was the difference between urine flow assessed by the Serenno device and hourly nursing assessments (Nurse), and detection of oliguria.

RESULTS

Thirty-seven patients completed the study, with 1,306 h of recording and a median of 25 measurement hours per patient. Bland and Altman analysis comparing the study device to camera measurements demonstrated good agreement, with a bias of -0.4 ml/h and 95% confidence intervals ranging from - 28 to 27ml/h. Concordance was 92%. The correlation between Camera and hourly nursing assessment of urine output was distinctly worse with a bias of 7.2 ml and limits of agreement extending from - 75 to + 107 ml. Severe oliguria (urine output < 0.3 ml/kg/h) lasting 2 h or more was common and observed in 8 (21%) of patients. Among the severe oliguric events lasting more than 3 consecutive hours, 6 (41%) were not detected or documented by the nursing staff. There were no device-related complications.

CONCLUSION

The Serenno Medical Automatic urine output measuring device required minimal supervision, little ICU nursing staff attention, and is sufficiently accurate and precise. In addition to providing continuous assessments of urine output, it was considerably more accurate than hourly nursing assessments.

Feasibility analysis of a novel non-invasive ultrasonographic method for the measurement of intra-abdominal pressure in the intensive care unit

Increased intra-abdominal pressure (IAP) is an important vital sign in critically ill patients and has a negative impact on morbidity and mortality. This study aimed to validate a novel non-invasive ultrasonographic approach to IAP measurement against the gold standard intra-bladder pressure (IBP) method. We conducted a prospective observational study in an adult medical ICU of a university hospital. IAP measurements using ultrasonography by two independent operators, with different experience levels (experienced, IAPUS1; inexperienced, IAPUS2), were compared with the gold standard IBP method performed by a third blinded operator. For the ultrasonographic method, decremental external pressure was applied on the anterior abdominal wall using a bottle filled with decreasing volumes of water. Ultrasonography looked at peritoneal rebound upon brisk withdrawal of the external pressure. The loss of peritoneal rebound was identified as the point where IAP was equal to or above the applied external pressure. Twenty-one patients underwent 74 IAP readings (range 2-15 mmHg). The number of readings per patient was 3.5 ± 2.5, and the abdominal wall thickness was 24.6 ± 13.1 mm. Bland and Altman's analysis showed a bias (0.39 and 0.61 mmHg) and precision (1.38 and 1.51 mmHg) for the comparison of IAPUS1 and IAPUS2 and vs. IBP, respectively with small limits of agreement that were in line with the research guidelines of the Abdominal Compartment Society (WSACS). Our novel ultrasound-based IAP method displayed good correlation and agreement between IAP and IBP at levels up to 15 mmHg and is an excellent solution for quick decision-making in critically ill patients.

In Vitro Validation of a Novel Continuous Intra-Abdominal Pressure Measurement System (TraumaGuard)

Introduction: Intra-abdominal pressure (IAP) has been recognized as an important vital sign in critically ill patients. Due to the high prevalence and incidence of intra-abdominal hypertension in surgical (trauma, burns, cardiac) and medical (sepsis, liver cirrhosis, acute kidney injury) patients, continuous IAP (CIAP) monitoring has been proposed. This research was aimed at validating a new CIAP monitoring device, the TraumaGuard from Sentinel Medical Technologies, against the gold standard (height of a water column) in an in vitro setting and performing a comparative analysis among different CIAP measurement technologies (including two intra-gastric and two intra-bladder measurement devices). A technical and clinical guideline addressing the strengths and weaknesses of each device is provided as well. Methods: Five different CIAP measurement devices (two intra-gastric and three intra-vesical), including the former CiMON, Spiegelberg, Serenno, TraumaGuard, and Accuryn, were validated against the gold standard water column pressure in a bench-top abdominal phantom. The impacts of body temperature and bladder fill volume (for the intra-vesical methods) were evaluated for each system. Subsequently, 48 h of continuous monitoring (n = 2880) on top of intermittent IAP (n = 300) readings were captured for each device. Using Pearson's and Lin's correlations, concordance, and Bland and Altman analyses, the accuracy, precision, percentage error, correlation and concordance coefficients, bias, and limits of agreement were calculated for all the different devices. We also performed error grid analysis on the CIAP measurements to provide an overview of the involved risk level due to wrong IAP measurements and calculated the area under the curve and time above a certain IAP threshold. Lastly, the robustness of each system in tracking the dynamic variations of the raw IAP signal due to respirations and heartbeats was evaluated as well. Results: The TraumaGuard was the only technology able to measure the IAP with an empty artificial bladder. No important temperature dependency was observed for the investigated devices except for the Spiegelberg, which displayed higher IAP values when the temperature was increased, but this could be adjusted through recalibration. All the studied devices showed excellent ability for IAP monitoring, although the intra-vesical IAP measurements seem more reliable. In general, the TraumaGuard, Accuryn, and Serenno showed better accuracy compared to intra-gastric measurement devices. On average, biases of +0.71, +0.93, +0.29, +0.25, and -0.06 mm Hg were observed for the CiMON, Spiegelberg, Serenno, TraumaGuard, and Accuryn, respectively. All of the equipment showed percentage errors smaller than 25%. Regarding the correlation and concordance coefficients, the Serenno and TraumaGuard showed the best results (R2 = 0.98, p = 0.001, concordance coefficient of 99.5%). Error grid analysis based on the Abdominal Compartment Society guidelines showed a very low associated risk level of inappropriate treatment strategies due to erroneous IAP measurements. Regarding the dynamic tracings of the raw IAP signal, all the systems can track respiratory variations and derived parameters; however, the CiMON was slightly superior compared to the other technologies. Conclusions: According to the research guidelines of the Abdominal Compartment Society (WSACS), this in vitro study shows that the TraumaGuard can be used interchangeably with the gold standard for measuring continuous IAP, even in an empty artificial bladder. Confirmation studies with the TraumaGuard in animals and humans are warranted to further validate these findings.

Multidisciplinary expert panel report on fluid stewardship: perspectives and practice

Although effective and appropriate fluid management is a critical aspect of quality care during hospitalization, the widespread adoption of consistent policies that ensure adequate fluid stewardship has been slow and heterogenous. Despite evidence-based guidelines on fluid management being available, clinical opinions continue to diverge on important aspects of care in this setting, and the consistency of guideline implementation is far from ideal. A multidisciplinary panel of leading practitioners and experts convened to discuss best practices for ongoing staff education, intravenous fluid therapy, new training technologies, and strategies to track the success of institutional fluid stewardship efforts. Fluid leads should be identified in every hospital to ensure consistency in fluid administration and monitoring. In this article, strategies to communicate the importance of effective fluid stewardship for the purposes of education, training, institutional support, and improvement of patient outcomes are reviewed and recommendations are summarized.

Albumin administration in septic shock-Protocol for post-hoc analyses of data from a multicentre RCT

BACKGROUND

Intravenous (IV) albumin is suggested for patients with septic shock who have received large amounts of IV crystalloids; a conditional recommendation based on moderate certainty of evidence. Clinical variation in the administration of IV albumin in septic shock may exist according to patient characteristics and location.

METHODS

This is a protocol and statistical analysis plan for a post-hoc secondary study of the Conservative versus Liberal Approach to Fluid Therapy of Septic Shock in Intensive Care (CLASSIC) RCT of 1554 adult ICU patients with septic shock. We will assess if specific baseline characteristics or trial site are associated with the administration of IV albumin during ICU stay using Cox models with competing events. All models will be adjusted for the treatment allocation in CLASSIC (restrictive vs. standard IV fluid), and all analyses will consider competing events (death, ICU discharge and loss-to-follow-up). We will present results as hazard ratios with 95% confidence intervals and p-values for the associations of baseline characteristics or site with IV albumin administration. Between-group differences (interactions) will be assessed using p-values from likelihood ratio tests. All results will be considered exploratory only.

DISCUSSION

This secondary study of the CLASSIC RCT may yield important insight into potential practice variation in the administration of albumin in septic shock.

The pathophysiological impact of intra-abdominal hypertension in pigs

BACKGROUND

Intra-abdominal hypertension and abdominal compartment syndrome are common with clinically significant consequences. We investigated the pathophysiological effects of raised IAP as part of a more extensive exploratory animal study. The study design included both pneumoperitoneum and mechanical intestinal obstruction models.

METHODS

Forty-nine female swine were divided into six groups: a control group (Cr; n = 5), three pneumoperitoneum groups with IAPs of 20mmHg (Pn20; n = 10), 30mmHg (Pn30; n = 10), 40mmHg (Pn40; n = 10), and two mechanical intestinal occlusion groups with IAPs of 20mmHg (MIO20; n = 9) and 30mmHg (MIO30; n = 5).

RESULTS

There were significant changes (p<0.05) noted in all organ systems, most notably systolic blood pressure (SBP) (p<0.001), cardiac index (CI) (p = 0.003), stroke volume index (SVI) (p<0.001), mean pulmonary airway pressure (MPP) (p<0.001), compliance (p<0.001), pO2 (p = 0.003), bicarbonate (p = 0.041), hemoglobin (p = 0.012), lipase (p = 0.041), total bilirubin (p = 0.041), gastric pH (p<0.001), calculated glomerular filtration rate (GFR) (p<0.001), and urine output (p<0.001). SVV increased progressively as the IAP increased with no obvious changes in intravascular volume status. There were no significant differences between the models regarding their impact on cardiovascular, respiratory, renal and gastrointestinal systems. However, significant differences were noted between the two models at 30mmHg, with MIO30 showing worse metabolic and hematological parameters, and Pn30 and Pn40 showing a more rapid rise in creatinine.

CONCLUSIONS

This study identified and quantified the impact of intra-abdominal hypertension at different pressures on several organ systems and highlighted the significance of even short-lived elevations. Two models of intra-abdominal pressure were used, with a mechanical obstruction model showing more rapid changes in metabolic and haematological changes. These may represent different underlying cellular and vascular pathophysiological processes, but this remains unclear.

Source control in emergency general surgery: WSES, GAIS, SIS-E, SIS-A guidelines

Intra-abdominal infections (IAI) are among the most common global healthcare challenges and they are usually precipitated by disruption to the gastrointestinal (GI) tract. Their successful management typically requires intensive resource utilization, and despite the best therapies, morbidity and mortality remain high. One of the main issues required to appropriately treat IAI that differs from the other etiologies of sepsis is the frequent requirement to provide physical source control. Fortunately, dramatic advances have been made in this aspect of treatment. Historically, source control was left to surgeons only. With new technologies non-surgical less invasive interventional procedures have been introduced. Alternatively, in addition to formal surgery open abdomen techniques have long been proposed as aiding source control in severe intra-abdominal sepsis. It is ironic that while a lack or even delay regarding source control clearly associates with death, it is a concept that remains poorly described. For example, no conclusive definition of source control technique or even adequacy has been universally accepted. Practically, source control involves a complex definition encompassing several factors including the causative event, source of infection bacteria, local bacterial flora, patient condition, and his/her eventual comorbidities. With greater understanding of the systemic pathobiology of sepsis and the profound implications of the human microbiome, adequate source control is no longer only a surgical issue but one that requires a multidisciplinary, multimodality approach. Thus, while any breach in the GI tract must be controlled, source control should also attempt to control the generation and propagation of the systemic biomediators and dysbiotic influences on the microbiome that perpetuate multi-system organ failure and death. Given these increased complexities, the present paper represents the current opinions and recommendations for future research of the World Society of Emergency Surgery, of the Global Alliance for Infections in Surgery of Surgical Infection Society Europe and Surgical Infection Society America regarding the concepts and operational adequacy of source control in intra-abdominal infections.

Fluid management strategies and their interaction with mechanical ventilation: from experimental studies to clinical practice

Patients on mechanical ventilation may receive intravenous fluids via restrictive or liberal fluid management. A clear and objective differentiation between restrictive and liberal fluid management strategies is lacking in the literature. The liberal approach has been described as involving fluid rates ranging from 1.2 to 12 times higher than the restrictive approach. A restrictive fluid management may lead to hypoperfusion and distal organ damage, and a liberal fluid strategy may result in endothelial shear stress and glycocalyx damage, cardiovascular complications, lung edema, and distal organ dysfunction. The association between fluid and mechanical ventilation strategies and how they interact toward ventilator-induced lung injury (VILI) could potentiate the damage. For instance, the combination of a liberal fluids and pressure-support ventilation, but not pressure control ventilation, may lead to further lung damage in experimental models of acute lung injury. Moreover, under liberal fluid management, the application of high positive end-expiratory pressure (PEEP) or an abrupt decrease in PEEP yielded higher endothelial cell damage in the lungs. Nevertheless, the translational aspects of these findings are scarce. The aim of this narrative review is to provide better understanding of the interaction between different fluid and ventilation strategies and how these interactions may affect lung and distal organs. The weaning phase of mechanical ventilation and the deresuscitation phase are not explored in this review.

Long-term effects of restriction of intravenous fluid in adult ICU patients with septic shock

PURPOSE

To assess long-term outcomes of restrictive versus standard intravenous (IV) fluid therapy in adult intensive care unit (ICU) patients with septic shock included in the European Conservative versus Liberal Approach to Fluid Therapy in Septic Shock in Intensive Care (CLASSIC) trial.

METHODS

We conducted the pre-planned analyses of mortality, health-related quality of life (HRQoL) using EuroQol (EQ)-5D-5L index values and EQ visual analogue scale (VAS), and cognitive function using Mini Montreal Cognitive Assessment (Mini MoCA) test at 1 year. Deceased patients were assigned numerical zero for HRQoL as a state equal to death and zero for cognitive function outcomes as worst possible score, and we used multiple imputation for missing data on HRQoL and cognitive function.

RESULTS

Among 1554 randomized patients, we obtained 1-year data on mortality in 97.9% of patients, HRQoL in 91.3%, and cognitive function in 86.3%. One-year mortality was 385/746 (51.3%) in the restrictive-fluid group versus 383/767 (49.9%) in the standard-fluid group, absolute risk difference 1.5%-points [99% confidence interval (CI) - 4.8 to 7.8]. Mean differences were 0.00 (99% CI - 0.06 to 0.05) for EQ-5D-5L index values, - 0.65 for EQ VAS (- 5.40 to 4.08), and - 0.14 for Mini MoCA (- 1.59 to 1.14) for the restrictive-fluid group versus the standard-fluid group. The results for survivors only were similar in both groups.

CONCLUSIONS

Among adult ICU patients with septic shock, restrictive versus standard IV fluid therapy resulted in similar survival, HRQoL, and cognitive function at 1 year, but clinically important differences could not be ruled out.

The unrestricted global effort to complete the COOL trial

BACKGROUND

Severe complicated intra-abdominal sepsis (SCIAS) has an increasing incidence with mortality rates over 80% in some settings. Mortality typically results from disruption of the gastrointestinal tract, progressive and self-perpetuating bio-mediator generation, systemic inflammation, and multiple organ failure. A further therapeutic option may be open abdomen (OA) management with negative peritoneal pressure therapy (NPPT) to remove inflammatory ascites and attenuate the systemic damage from SCIAS, although there are definite risks of leaving the abdomen open whenever it might possibly be closed. This potential therapeutic paradigm is the rationale being assessed in the Closed Or Open after Laparotomy (COOL trial) ( https://clinicaltrials.gov/ct2/show/NCT03163095 ). Initially, the COOL trial received Industry sponsorship; however, this funding mandated the use of a specific trademarked and expensive NPPT device in half of the patients allocated to the intervention (open) arm. In August 2022, the 3 M/Acelity Corporation without consultation but within the terms of the contract canceled the financial support of the trial. Although creating financial difficulty, there is now no restriction on specific NPPT devices and removing a cost-prohibitive intervention creates an opportunity to expand the COOL trial to a truly global basis. This document describes the evolution of the COOL trial, with a focus on future opportunities for global growth of the study.

METHODS

The COOL trial is the largest prospective randomized controlled trial examining the random allocation of SCIAS patients intra-operatively to either formal closure of the fascia or the use of the OA with an application of an NPPT dressing. Patients are eligible if they have free uncontained intraperitoneal contamination and physiologic derangements exemplified by septic shock OR severely adverse predicted clinical outcomes. The primary outcome is intended to definitively inform global practice by conclusively evaluating 90-day survival. Initial recruitment has been lower than hoped but satisfactory, and the COOL steering committee and trial investigators intend with increased global support to continue enrollment until recruitment ensures a definitive answer.

DISCUSSION

OA is mandated in many cases of SCIAS such as the risk of abdominal compartment syndrome associated with closure, or a planned second look as for example part of "damage control"; however, improved source control (locally and systemically) is the most uncertain indication for an OA. The COOL trial seeks to expand potential sites and proceed with the evaluation of NPPT agnostic to device, to properly examine the hypothesis that this treatment attenuates systemic damage and improves survival. This approach will not affect internal validity and should improve the external validity of any observed results of the intervention.

TRIAL REGISTRATION

National Institutes of Health ( https://clinicaltrials.gov/ct2/show/NCT03163095 ).

Is it feasible to measure intra-abdominal pressure using a balloon-tipped rectal catheter? Results of a validation study

The gold standard to measure intra-abdominal pressure (IAP) is intra-vesical measurement via the urinary bladder. However, this technique is restricted in ambulatory settings because of the risk of iatrogenic urinary tract infections. Rectal IAP measurements (IAP_rect) may overcome these limitations, but requires validation. This validation study compares the IAP_rect technique against gold standard intra-vesical IAP measurements (IAP_ves). IAP_rect using an air-filled balloon catheter and IAP_ves using Foley Manometer Low Volume were measured simultaneously in sedated and ventilated patients. Measurements were performed twice in different positions (supine and HOB 45° elevated head of bed) and with an external abdominal pressure belt. Sixteen patients were included. Seven were not eligible for analysis due to unreliable IAP_rect values. IAP_rect was significantly higher than IAP_ves for all body positions (p < 0.01) and the correlation between IAP_ves and IAP_rect was poor and not significant in each position (p ≥ 0.25, R² < 0.6, Lin's CCC < 0.8, bias - 8.1 mmHg and precision of 5.6 mmHg with large limits of agreement between - 19 to 2.9 mmHg, high percentage error 67.3%, and low concordance 86.2%). Repeatability of IAP_rect was not reliable (R = 0.539, p = 0.315). For both techniques, measurements with the external abdominal pressure belt were significantly higher compared to those without (p < 0.03). IAP_rect has important shortcomings making IAP estimation using a rectal catheter unfeasible because the numbers cannot be trusted nor validated.

Protection of the endothelium and endothelial glycocalyx by hydrogen against ischaemia-reperfusion injury in a porcine model of cardiac arrest

BACKGROUND

Hydrogen is a potent antioxidant agent that can easily be administered by inhalation. The aim of the study was to evaluate whether hydrogen protects the endothelial glycocalyx layer after successful cardiopulmonary resuscitation (CPR).

METHODS

Fourteen anesthetized pigs underwent CPR after induced ventricular fibrillation. During CPR and return of spontaneous circulation, 2% hydrogen gas was administered to seven pigs (hydrogen group) and seven constituted a control group. Biochemistry and sublingual microcirculation were assessed at baseline, during CPR, at the 15th, 30th, 60th, 120th minute.

RESULTS

All seven subjects from the hydrogen group and six subjects in the control group were successfully resuscitated after 6-10 minutes. At baseline, there were no statistically significant differences in examined variables. After the CPR, blood pH, base excess, and lactate showed significantly smaller deterioration in the hydrogen group than in the control group. By contrast, plasma syndecan-1 and the measured variables obtained via sublingual microcirculation did not change after the CPR; and were virtually identical between the two groups.

CONCLUSION

In pigs, hydrogen gas inhalation during CPR and post-resuscitation care was associated with less pronounced metabolic acidosis compared to controls. However, we could not find evidence of injury to the endothelium or glycocalyx in any studied groups.

Extravascular lung water levels are associated with mortality: a systematic review and meta-analysis

Background

The prognostic value of extravascular lung water (EVLW) measured by transpulmonary thermodilution (TPTD) in critically ill patients is debated. We performed a systematic review and meta-analysis of studies assessing the effects of TPTD-estimated EVLW on mortality in critically ill patients.

Methods

Cohort studies published in English from Embase, MEDLINE, and the Cochrane Database of Systematic Reviews from 1960 to 1 June 2021 were systematically searched. From eligible studies, the values of the odds ratio (OR) of EVLW as a risk factor for mortality, and the value of EVLW in survivors and non-survivors were extracted. Pooled OR were calculated from available studies. Mean differences and standard deviation of the EVLW between survivors and non-survivors were calculated. A random effects model was computed on the weighted mean differences across the two groups to estimate the pooled size effect. Subgroup analyses were performed to explore the possible sources of heterogeneity.

Results

Of the 18 studies included (1296 patients), OR could be extracted from 11 studies including 905 patients (464 survivors vs. 441 non-survivors), and 17 studies reported EVLW values of survivors and non-survivors, including 1246 patients (680 survivors vs. 566 non-survivors). The pooled OR of EVLW for mortality from eleven studies was 1.69 (95% confidence interval (CI) [1.22; 2.34], p < 0.0015). EVLW was significantly lower in survivors than non-survivors, with a mean difference of −4.97 mL/kg (95% CI [−6.54; −3.41], p < 0.001). The results regarding OR and mean differences were consistent in subgroup analyses.

Conclusions

The value of EVLW measured by TPTD is associated with mortality in critically ill patients and is significantly higher in non-survivors than in survivors. This finding may also be interpreted as an indirect confirmation of the reliability of TPTD for estimating EVLW at the bedside. Nevertheless, our results should be considered cautiously due to the high risk of bias of many studies included in the meta-analysis and the low rating of certainty of evidence.

Trial registration the study protocol was prospectively registered on PROSPERO: CRD42019126985.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-022-04061-6.

Biological impact of restrictive and liberal fluid strategies at low and high PEEP levels on lung and distal organs in experimental acute respiratory distress syndrome

Background: Fluid regimens in acute respiratory distress syndrome (ARDS) are conflicting. The amount of fluid and positive end-expiratory pressure (PEEP) level may interact leading to ventilator-induced lung injury (VILI). We therefore evaluated restrictive and liberal fluid strategies associated with low and high PEEP levels with regard to lung and kidney damage, as well as cardiorespiratory function in endotoxin-induced ARDS.

Methods: Thirty male Wistar rats received an intratracheal instillation of Escherichia coli lipopolysaccharide. After 24 h, the animals were anesthetized, protectively ventilated (V_T = 6 ml/kg), and randomized to restrictive (5 ml/kg/h) or liberal (40 ml/kg/h) fluid strategies (Ringer lactate). Both groups were then ventilated with PEEP = 3 cmH₂O (PEEP3) and PEEP = 9 cmH₂O (PEEP9) for 1 h (n = 6/group). Echocardiography, arterial blood gases, and lung mechanics were evaluated throughout the experiments. Histologic analyses were done on the lungs, and molecular biology was assessed in lungs and kidneys using six non-ventilated animals with no fluid therapy.

Results: In lungs, the liberal group showed increased transpulmonary plateau pressure compared with the restrictive group (liberal, 23.5 ± 2.9 cmH₂O; restrictive, 18.8 ± 2.3 cmH₂O, p = 0.046) under PEEP = 9 cmH₂O. Gene expression associated with inflammation (interleukin [IL]-6) was higher in the liberal-PEEP9 group than the liberal-PEEP3 group (p = 0.006) and restrictive-PEEP9 (p = 0.012), Regardless of the fluid strategy, lung mechanical power and the heterogeneity index were higher, whereas birefringence for claudin-4 and zonula-ocludens-1 gene expression were lower in the PEEP9 groups. Perivascular edema was higher in liberal groups, regardless of PEEP levels. Markers related to damage to epithelial cells [club cell secreted protein (CC16)] and the extracellular matrix (syndecan) were higher in the liberal-PEEP9 group than the liberal-PEEP3 group (p = 0.010 and p = 0.024, respectively). In kidneys, the expression of IL-6 and neutrophil gelatinase-associated lipocalin was higher in PEEP9 groups, regardless of the fluid strategy. For the liberal strategy, PEEP = 9 cmH₂O compared with PEEP = 3 cmH₂O reduced the right ventricle systolic volume (37%) and inferior vena cava collapsibility index (45%).

Conclusion: The combination of a liberal fluid strategy and high PEEP led to more lung damage. The application of high PEEP, regardless of the fluid strategy, may also be deleterious to kidneys.

Hemoadsorption in the critically ill-Final results of the International CytoSorb Registry

The aim of the current paper is to summarize the results of the International CytoSorb Registry. Data were collected on patients of the intensive care unit. The primary endpoint was actual in-hospital mortality compared to the mortality predicted by APACHE II score. The main secondary endpoints were SOFA scores, inflammatory biomarkers and overall evaluation of the general condition. 1434 patients were enrolled. Indications for hemoadsorption were sepsis/septic shock (N = 936); cardiac surgery perioperatively (N = 172); cardiac surgery postoperatively (N = 67) and "other" reasons (N = 259). APACHE-II-predicted mortality was 62.0±24.8%, whereas observed hospital mortality was 50.1%. Overall SOFA scores did not change but cardiovascular and pulmonary SOFA scores decreased by 0.4 [-0.5;-0.3] and -0.2 [-0.3;-0.2] points, respectively. Serum procalcitonin and C-reactive protein levels showed significant reduction: -15.4 [-19.6;-11.17] ng/mL; -17,52 [-70;44] mg/L, respectively. In the septic cohort PCT and IL-6 also showed significant reduction: -18.2 [-23.6;-12.8] ng/mL; -2.6 [-3.0;-2.2] pg/mL, respectively. Evaluation of the overall effect: minimal improvement (22%), much improvement (22%) and very much improvement (10%), no change observed (30%) and deterioration (4%). There was no significant difference in the primary outcome of mortality, but there were improvements in cardiovascular and pulmonary SOFA scores and a reduction in PCT, CRP and IL-6 levels. Trial registration: ClinicalTrials.gov Identifier: NCT02312024 (retrospectively registered).

Intravenous fluid therapy in patients with severe acute pancreatitis admitted to the intensive care unit: a narrative review

Patients with acute pancreatitis (AP) often require ICU admission, especially when signs of multiorgan failure are present, a condition that defines AP as severe. This disease is characterized by a massive pancreatic release of pro-inflammatory cytokines that causes a systemic inflammatory response syndrome and a profound intravascular fluid loss. This leads to a mixed hypovolemic and distributive shock and ultimately to multiorgan failure. Aggressive fluid resuscitation is traditionally considered the mainstay treatment of AP. In fact, all available guidelines underline the importance of fluid therapy, particularly in the first 24–48 h after disease onset. However, there is currently no consensus neither about the type, nor about the optimal fluid rate, total volume, or goal of fluid administration. In general, a starting fluid rate of 5–10 ml/kg/h of Ringer’s lactate solution for the first 24 h has been recommended. Fluid administration should be aggressive in the first hours, and continued only for the appropriate time frame, being usually discontinued, or significantly reduced after the first 24–48 h after admission. Close clinical and hemodynamic monitoring along with the definition of clear resuscitation goals are fundamental. Generally accepted targets are urinary output, reversal of tachycardia and hypotension, and improvement of laboratory markers. However, the usefulness of different endpoints to guide fluid therapy is highly debated. The importance of close monitoring of fluid infusion and balance is acknowledged by most available guidelines to avoid the deleterious effect of fluid overload. Fluid therapy should be carefully tailored in patients with severe AP, as for other conditions frequently managed in the ICU requiring large fluid amounts, such as septic shock and burn injury. A combination of both noninvasive clinical and invasive hemodynamic parameters, and laboratory markers should guide clinicians in the early phase of severe AP to meet organ perfusion requirements with the proper administration of fluids while avoiding fluid overload. In this narrative review the most recent evidence about fluid therapy in severe AP is discussed and an operative algorithm for fluid administration based on an individualized approach is proposed.

Intravenous fluid therapy in perioperative and critical care setting-Knowledge test and practice: An international cross-sectional survey

PURPOSE

In the absence of recent international recommendations supported by scientific societies like Anesthesiology or Intensive Care Medicine, healthcare professionals (HCP) knowledge on IV fluid is expected to vary. We undertook a cross-sectional survey, aiming to assess prescription patterns and test the knowledge of HCP for IV fluid use in the operating room (OR) and intensive care unit (ICU).

METHODS

An online international cross-sectional survey was conducted between October 20, 2019, and November 27, 2021. The survey included multiple-choice questions on demographics, practice patterns and knowledge of IV fluids, and a hemodynamically unstable patient assessment.

RESULTS

1045 HCP, from 97 countries responded to the survey. Nearly three-quarters reported the non-existence of internal hospital or ICU-based guidelines on IV fluids. The respondents' mean score on the knowledge assessment questions was 46.4 ± 14.4. The cumulative mean scores were significantly higher among those supervising trainees (p = 0.02), specialists (p < 0.001) and those working in high-income (p < 0.001) countries. Overall performance of respondents on the knowledge testing for IV fluid was unsatisfactory with only 6.5% respondents performed above average.

CONCLUSION

There is a wide difference in the knowledge and prescription of IV fluids among the HCP surveyed. These findings reflect the urgent need for education on IV fluids.

Postoperative pain management in non-traumatic emergency general surgery: WSES-GAIS-SIAARTI-AAST guidelines

BACKGROUND

Non-traumatic emergency general surgery involves a heterogeneous population that may present with several underlying diseases. Timeous emergency surgical treatment should be supplemented with high-quality perioperative care, ideally performed by multidisciplinary teams trained to identify and handle complex postoperative courses. Uncontrolled or poorly controlled acute postoperative pain may result in significant complications. While pain management after elective surgery has been standardized in perioperative pathways, the traditional perioperative treatment of patients undergoing emergency surgery is often a haphazard practice. The present recommended pain management guidelines are for pain management after non-traumatic emergency surgical intervention. It is meant to provide clinicians a list of indications to prescribe the optimal analgesics even in the absence of a multidisciplinary pain team.

MATERIAL AND METHODS

An international expert panel discussed the different issues in subsequent rounds. Four international recognized scientific societies: World Society of Emergency Surgery (WSES), Global Alliance for Infection in Surgery (GAIS), Italian Society of Anesthesia, Analgesia Intensive Care (SIAARTI), and American Association for the Surgery of Trauma (AAST), endorsed the project and approved the final manuscript.

CONCLUSION

Dealing with acute postoperative pain in the emergency abdominal surgery setting is complex, requires special attention, and should be multidisciplinary. Several tools are available, and their combination is mandatory whenever is possible. Analgesic approach to the various situations and conditions should be patient based and tailored according to procedure, pathology, age, response, and available expertise. A better understanding of the patho-mechanisms of postoperative pain for short- and long-term outcomes is necessary to improve prophylactic and treatment strategies.

Potentially Detrimental Effects of Hyperosmolality in Patients Treated for Traumatic Brain Injury

Hyperosmotic therapy is commonly used to treat intracranial hypertension in traumatic brain injury patients. Unfortunately, hyperosmolality also affects other organs. An increase in plasma osmolality may impair kidney, cardiac, and immune function, and increase blood–brain barrier permeability. These effects are related not only to the type of hyperosmotic agents, but also to the level of hyperosmolality. The commonly recommended osmolality of 320 mOsm/kg H₂O seems to be the maximum level, although an increase in plasma osmolality above 310 mOsm/kg H₂O may already induce cardiac and immune system disorders. The present review focuses on the adverse effects of hyperosmolality on the function of various organs.

The effect of fluid bolus administration on cerebral tissue oxygenation in post-cardiac arrest patients

PURPOSE

Fluid boluses (FB) are often used in post-cardiac arrest (CA) patients with haemodynamic instability. Although FB may improve cardiac output (CO) and mean arterial pressure (MAP), FB may also increase central venous pressure (CVP), reduce arterial PaO₂, dilute haemoglobin and cause interstitial oedema. The aim of the present study was to investigate the net effect of FB administration on cerebral tissue oxygenation saturation (SctO₂) in post-CA patients.

METHODS

Pre-planned sub-study of the Neuroprotect post-CA trial (NCT02541591). Patients with anticipated fluid responsiveness based on stroke volume variation (SVV) or passive leg raising test were administered a FB of 500 ml plasma-lyte A (Baxter Healthcare) and underwent pre- and post-FB assessments of stroke volume, CO, MAP, CVP, haemoglobin, PaO₂ and SctO₂.

RESULTS

52 patients (mean age 64 ± 12 years, 75% male) received a total of 115 FB. Although administration of a FB resulted in a significant increase of stroke volume (63 ± 22 vs 67 ± 23 mL, p = 0.001), CO (4,2 ± 1,6 vs 4,4 ± 1,7 L/min, p = 0.001) and MAP (74,8 ± 13,2 vs 79,2 ± 12,9 mmHg, p = 0.004), it did not improve SctO₂ (68.54 ± 6.99 vs 68.70 ± 6.80%, p = 0.49). Fluid bolus administration also resulted in a significant increase of CVP (10,0 ± 4,5 vs 10,7 ± 4,9 mmHg, p = 0.02), but did not affect PaO₂ (99 ± 31 vs 94 ± 31 mmHg, p = 0.15) or haemoglobin concentrations (12,9 ± 2,1 vs 12,8 ± 2,2 g/dL, p = 0.10). In a multivariate model, FB-induced changes in CO (beta 0,77; p = 0.004) and in CVP (beta -0,23; p = 0.02) but not in MAP (beta 0,02; p = 0.18) predicted post-FB ΔSctO₂.

CONCLUSIONS

Despite improvements in CO and MAP, FB administration did not improve SctO₂ in post-cardiac arrest patients.

Dosing of Extracorporeal Cytokine Removal In Septic Shock (DECRISS): protocol of a prospective, randomised, adaptive, multicentre clinical trial

INTRODUCTION

Sepsis and septic shock have mortality rates between 20% and 50%. In sepsis, the immune response becomes dysregulated, which leads to an imbalance between proinflammatory and anti-inflammatory mediators. When standard therapeutic measures fail to improve patients' condition, additional therapeutic alternatives are applied to reduce morbidity and mortality. One of the most recent alternatives is extracorporeal cytokine adsorption with a device called CytoSorb. This study aims to compare the efficacy of standard medical therapy and continuous extracorporeal cytokine removal with CytoSorb therapy in patients with early refractory septic shock. Furthermore, we compare the dosing of CytoSorb adsorber device changed every 12 or 24 hours.

METHODS AND ANALYSIS

It is a prospective, randomised, controlled, open-label, international, multicentre, phase III study. Patients fulfilling the inclusion criteria will be randomly assigned to receive standard medical therapy (group A) or-in addition to standard treatment-CytoSorb therapy. CytoSorb treatment will be continuous and last for at least 24 hours, CytoSorb adsorber device will be changed every 12 (group B) or 24 hours (group C). Our primary outcome is shock reversal (no further need or a reduced (≤10% of the maximum dose) vasopressor requirement for 3 hours) and time to shock reversal (number of hours elapsed from the start of the treatment to shock reversal).Based on sample size calculation, 135 patients (1:1:1) will need to be enrolled in the study. A predefined interim analysis will be performed after reaching 50% of the planned sample size, therefore, the corrected level of significance (p value) will be 0.0294.

ETHICS AND DISSEMINATION

Ethics approval was obtained from the Scientific and Research Ethics Committee of the Hungarian Medical Research Council (OGYÉI/65049/2020). Results will be submitted for publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT04742764; Pre-results.

A porcine model of endothelial glycocalyx damage by enzymatic digestion: A pilot study

BACKGROUND

The endothelial glycocalyx (EG) plays a vital role in the physiology and pathophysiology of human microcirculation. Having relevant EG damage model would be important tool for testing new interventions aiming at EG protection and recovery. We describe the first in vivo EG damage model in pig.

OBJECTIVE

To investigate the course of animal EG damage induced by specific enzymes.

MATERIAL AND METHODS

Four anesthetized piglets received enzymes: 1g hyaluronidase and 25 IU heparanase I intravenously. Blood and urine samples were collected at baseline and 20/40/60/80/100/120 min for detecting markers of endothelial and EG function. Sublingual microcirculation and EG thickness were assessed by Side-stream Dark Field (SDF) imaging and Perfused Boundary Region (PBR) respectively. EG of the mesentery artery was visualized in fluorescent microscopy.

RESULTS

Biochemical marker of EG damage syndecan-1 showed temporary increase with return to baseline and was reflected by PBR values. Albumin levels suggested brief period of capillary leakage (decrease in the serum, increase in the urine) with a trend to normalization. Urine glycosaminoglycans peaked at 120 minutes. Microcirculatory perfusion parameter showed significant alteration. Diffusion parameters were altered with no statistical significance.

CONCLUSION

EG damage induced by specific enzymes was reflected by temporary changes of biochemical makers together with alteration of microcirculation and changes in fluorescent microscopy of EG layer. Our results support to further validate presented model of EG damage on a larger number of animals.

Fluid-induced harm in the hospital: look beyond volume and start considering sodium. From physiology towards recommendations for daily practice in hospitalized adults

PURPOSE

Iatrogenic fluid overload is a potential side effect of intravenous fluid therapy in the hospital. Little attention has been paid to sodium administration as a separate cause of harm. With this narrative review, we aim to substantiate the hypothesis that a considerable amount of fluid-induced harm is caused not only by fluid volume, but also by the sodium that is administered to hospitalized patients.

METHODS

We show how a regular dietary sodium intake is easily surpassed by the substantial amounts of sodium that are administered during typical hospital stays. The most significant sodium burdens are caused by isotonic maintenance fluid therapy and by fluid creep, defined as the large volume unintentionally administered to patients in the form of dissolved medication. In a section on physiology, we elaborate on the limited renal handling of an acute sodium load. We demonstrate how the subsequent retention of water is an energy-demanding, catabolic process and how free water is needed to excrete large burdens of sodium. We quantify the effect size of sodium-induced fluid retention and discuss its potential clinical impact. Finally, we propose preventive measures, discuss the benefits and risks of low-sodium maintenance fluid therapy, and explore options for reducing the amount of sodium caused by fluid creep.

CONCLUSION

The sodium burdens caused by isotonic maintenance fluids and fluid creep are responsible for an additional and avoidable derailment of fluid balance, with presumed clinical consequences. Moreover, the handling of sodium overload is characterized by increased catabolism. Easy and effective measures for reducing sodium load and fluid retention include choosing a hypotonic rather than isotonic maintenance fluid strategy (or avoiding these fluids when enough free water is provided through other sources) and dissolving as many medications as possible in glucose 5%.

Intra-abdominal hypertension and hypoxic respiratory failure together predict adverse outcome - A sub-analysis of a prospective cohort

PURPOSE

To assess whether the combination of intra-abdominal hypertension (IAH, intra-abdominal pressure ≥ 12 mmHg) and hypoxic respiratory failure (HRF, PaO2/FiO2 ratio < 300 mmHg) in patients receiving invasive ventilation is an independent risk factor for 90- and 28-day mortality as well as ICU- and ventilation-free days.

METHODS

Mechanically ventilated patients who had blood gas analyses performed and intra-abdominal pressure measured, were included from a prospective cohort. Subgroups were defined by the absence (Group 1) or the presence of either IAH (Group 2) or HRF (Group 3) or both (Group 4). Mixed-effects regression analysis was performed.

RESULTS

Ninety-day mortality increased from 16% (Group 1, n = 50) to 30% (Group 2, n = 20) and 27% (Group 3, n = 100) to 49% (Group 4, n = 142), log-rank test p < 0.001. The combination of IAH and HRF was associated with increased 90- and 28-day mortality as well as with fewer ICU- and ventilation-free days. The association with 90-day mortality was no longer present after adjustment for independent variables. However, the association with 28-day mortality, ICU- and ventilation-free days persisted after adjusting for independent variables.

CONCLUSIONS

In our sub-analysis, the combination of IAH and HRF was not independently associated with 90-day mortality but independently increased the odds of 28-day mortality, and reduced the number of ICU- and ventilation-free days.

Future developments in the imaging of the gastrointestinal tract: the role of ultrasound

PURPOSE OF REVIEW

The purpose of this review is to summarize the utilization and most recent developments with regard to the use of ultrasound when imaging the abdomen and gastrointestinal tract.

RECENT FINDINGS

Although the use of ultrasound to assess the anatomy of the various abdominal organs is well established within radiology and critical care, its use as part of functional and physiological assessment is still evolving. Recent developments have extended the use of ultrasound beyond standard B-mode/2D imaging techniques to incorporate more functional and haemodynamic assessment. These include the use of contrast-enhanced ultrasound (CEUS), elastography, and colour Doppler techniques.

SUMMARY

Whilst Doppler techniques are reasonably well established within critical care ultrasound (CCUS), especially in echocardiography, CEUS and elastography are less well known. CEUS utilizes a purely intravascular contrast agent whilst elastography measures the degree of deformation or stiffness in various organs. Whilst their use individually may be limited; they may play a role in a multiparametric assessment. Mirroring the overall trends in critical care ultrasound development, abdominal ultrasound assessment is best integrated in a holistic approach and adapted to the individual patient.

Expert consensus statements for the management of COVID-19-related acute respiratory failure using a Delphi method

BACKGROUND

Coronavirus disease 2019 (COVID-19) pandemic has caused unprecedented pressure on healthcare system globally. Lack of high-quality evidence on the respiratory management of COVID-19-related acute respiratory failure (C-ARF) has resulted in wide variation in clinical practice.

METHODS

Using a Delphi process, an international panel of 39 experts developed clinical practice statements on the respiratory management of C-ARF in areas where evidence is absent or limited. Agreement was defined as achieved when > 70% experts voted for a given option on the Likert scale statement or > 80% voted for a particular option in multiple-choice questions. Stability was assessed between the two concluding rounds for each statement, using the non-parametric Chi-square (χ²) test (p < 0·05 was considered as unstable).

RESULTS

Agreement was achieved for 27 (73%) management strategies which were then used to develop expert clinical practice statements. Experts agreed that COVID-19-related acute respiratory distress syndrome (ARDS) is clinically similar to other forms of ARDS. The Delphi process yielded strong suggestions for use of systemic corticosteroids for critical COVID-19; awake self-proning to improve oxygenation and high flow nasal oxygen to potentially reduce tracheal intubation; non-invasive ventilation for patients with mixed hypoxemic-hypercapnic respiratory failure; tracheal intubation for poor mentation, hemodynamic instability or severe hypoxemia; closed suction systems; lung protective ventilation; prone ventilation (for 16-24 h per day) to improve oxygenation; neuromuscular blocking agents for patient-ventilator dyssynchrony; avoiding delay in extubation for the risk of reintubation; and similar timing of tracheostomy as in non-COVID-19 patients. There was no agreement on positive end expiratory pressure titration or the choice of personal protective equipment.

CONCLUSION

Using a Delphi method, an agreement among experts was reached for 27 statements from which 20 expert clinical practice statements were derived on the respiratory management of C-ARF, addressing important decisions for patient management in areas where evidence is either absent or limited.

TRIAL REGISTRATION

The study was registered with Clinical trials.gov Identifier: NCT04534569.

Expert consensus statements for the management of COVID-19-related acute respiratory failure using a Delphi method

BACKGROUND

Coronavirus disease 2019 (COVID-19) pandemic has caused unprecedented pressure on healthcare system globally. Lack of high-quality evidence on the respiratory management of COVID-19-related acute respiratory failure (C-ARF) has resulted in wide variation in clinical practice.

METHODS

Using a Delphi process, an international panel of 39 experts developed clinical practice statements on the respiratory management of C-ARF in areas where evidence is absent or limited. Agreement was defined as achieved when > 70% experts voted for a given option on the Likert scale statement or > 80% voted for a particular option in multiple-choice questions. Stability was assessed between the two concluding rounds for each statement, using the non-parametric Chi-square (χ²) test (p < 0·05 was considered as unstable).

RESULTS

Agreement was achieved for 27 (73%) management strategies which were then used to develop expert clinical practice statements. Experts agreed that COVID-19-related acute respiratory distress syndrome (ARDS) is clinically similar to other forms of ARDS. The Delphi process yielded strong suggestions for use of systemic corticosteroids for critical COVID-19; awake self-proning to improve oxygenation and high flow nasal oxygen to potentially reduce tracheal intubation; non-invasive ventilation for patients with mixed hypoxemic-hypercapnic respiratory failure; tracheal intubation for poor mentation, hemodynamic instability or severe hypoxemia; closed suction systems; lung protective ventilation; prone ventilation (for 16-24 h per day) to improve oxygenation; neuromuscular blocking agents for patient-ventilator dyssynchrony; avoiding delay in extubation for the risk of reintubation; and similar timing of tracheostomy as in non-COVID-19 patients. There was no agreement on positive end expiratory pressure titration or the choice of personal protective equipment.

CONCLUSION

Using a Delphi method, an agreement among experts was reached for 27 statements from which 20 expert clinical practice statements were derived on the respiratory management of C-ARF, addressing important decisions for patient management in areas where evidence is either absent or limited.

TRIAL REGISTRATION

The study was registered with Clinical trials.gov Identifier: NCT04534569.

A concise overview of non-invasive intra-abdominal pressure measurement techniques: from bench to bedside

This review presents an overview of previously reported non-invasive intra-abdominal pressure (IAP) measurement techniques. Each section covers the basic physical principles and methodology of the various measurement techniques, the experimental results, and the advantages and disadvantages of each method. The most promising non-invasive methods for IAP measurement are microwave reflectometry and ultrasound assessment, in combination with an applied external force.

Ventilator-associated bacterial pneumonia in coronavirus 2019 disease, a retrospective monocentric cohort study

Introduction

Severe coronavirus 2019 disease (CoViD-19) may lead to respiratory failure and mechanical ventilation. Therefore, ventilator associated pneumonia (VAP) may complicate the course of the disease. The aim of the current article was to investigate possible predictive factors for bacterial VAP on a retrospective manner, in a cohort of mechanically ventilated CoViD-19 patients. Additionally, determinant factors of lethality were analyzed.

Methods

Medical records of patients hospitalized in the intensive care units (ICU) at the university hospital UZ Brussel during the epidemic were reviewed. VAP was defined following the National Healthcare Safety Network 2017 criteria. Univariate and multivariate logistic regressions analyses were performed.

Results

Among the 39 patients included in the study, 54% were diagnosed with bacterial VAP. Case fatality rate was 44%, but 59% of the deceased patients had a do-not-resuscitate status. Multivariate logistic regression for prediction of VAP showed significant differences in duration of ICU hospitalization and in minimal lung compliance.

Additional analyses were performed on CoViD-19 patients who were affected by bacterial respiratory superinfection. The responsible pathogens correspond to the commonly found bacteria in VAP. However, 71% of the isolated germs were multi-drug resistant and bacteraemia was reported in 38%. Multivariate analyses for prediction of lethality found significant difference in SOFA score.

Conclusions

Mechanically ventilated CoViD-19 patients might frequently develop VAP. Longer ICU hospitalization was associated with pulmonary superinfection in the current cohort. Moreover, decreased minimal lung compliance was correlated to VAP and higher SOFA score at VAP diagnosis was associated with lethality.

Modeling intra-abdominal volume and respiratory driving pressure during pneumoperitoneum insufflation-a patient-level data meta-analysis

During pneumoperitoneum, intra-abdominal pressure (IAP) is usually kept at 12-14 mmHg. There is no clinical benefit in IAP increments if they do not increase intra-abdominal volume IAV. We aimed to estimate IAV (ΔIAV) and respiratory driving pressure changes (ΔP_RS) in relation to changes in IAP (ΔIAP). We carried out a patient-level meta-analysis of 204 adult patients with available data on IAV and ΔP_RS during pneumoperitoneum from three trials assessing the effect of IAP on postoperative recovery and airway pressure during laparoscopic surgery under general anesthesia. The primary endpoint was ΔIAV, and the secondary endpoint was ΔP_RS. The endpoints' response to ΔIAP was modeled using mixed multivariable Bayesian regression to estimate which mathematical function best fitted it. IAP values on the pressure-volume (PV) curve where the endpoint rate of change according to IAP decreased were identified. Abdomino-thoracic transmission (ATT) rate, that is, the rate ΔP_RS change to ΔIAP was also estimated. The best-fitting function was sigmoid logistic and linear for IAV and ΔP_RS response, respectively. Increments in IAV reached a plateau at 6.0 [95%CI 5.9-6.2] L. ΔIAV for each ΔIAP decreased at IAP ranging from 9.8 [95%CI 9.7-9.9] to 12.2 [12.0-12.3] mmHg. ATT rate was 0.65 [95%CI 0.62-0.68]. One mmHg of IAP raised ΔP_RS 0.88 cmH₂O. During pneumoperitoneum, IAP has a nonlinear relationship with IAV and a linear one with ΔP_RS. IAP should be set below the point where IAV gains diminish.NEW & NOTEWORTHY We found that intra-abdominal volume changes related to intra-abdominal pressure increase reached a plateau with diminishing gains in commonly used pneumoperitoneum pressure ranges. We also found a linear relationship between intra-abdominal pressure and respiratory driving pressure, a known marker of postoperative pulmonary complications.

Do we have the guts to go? The abdominal compartment, intra-abdominal hypertension, the human microbiome and exploration class space missions

Humans are destined to explore space, yet critical illness and injury may be catastrophically limiting for extraterrestrial travel. Humans are superorganisms living in symbiosis with their microbiomes, whose genetic diversity dwarfs that of humans. Symbiosis is critical and imbalances are associated with disease, occurring within hours of serious illness and injury. There are many characteristics of space flight that negatively influence the microbiome, especially deep space itself, with its increased radiation and absence of gravity. Prolonged weightlessness causes many physiologic changes that are detrimental; some resemble aging and will adversely affect the ability to tolerate critical illness or injury and subsequent treatment. Critical illness-induced intra-abdominal hypertension (IAH) may induce malperfusion of both the viscera and microbiome, with potentially catastrophic effects. Evidence from animal models confirms profound IAH effects on the gut, namely ischemia and disruption of barrier function, mechanistically linking IAH to resultant organ dysfunction. Therefore, a pathologic dysbiome, space-induced immune dysfunction and a diminished cardiorespiratory reserve with exacerbated susceptibility to IAH, imply that a space-deconditioned astronaut will be vulnerable to IAH-induced gut malperfusion. This sets the stage for severe gut ischemia and massive biomediator generation in an astronaut with reduced cardiorespiratory/immunological capacity. Fortunately, experiments in weightless analogue environments suggest that IAH may be ameliorated by conformational abdominal wall changes and a resetting of thoracoabdominal mechanics. Thus, review of the interactions of physiologic changes with prolonged weightlessness and IAH is required to identify appropriate questions for planning exploration class space surgical care.

Do we have the guts to go? The abdominal compartment, intra-abdominal hypertension, the human microbiome and exploration class space missions

Humans are destined to explore space, yet critical illness and injury may be catastrophically limiting for extraterrestrial travel. Humans are superorganisms living in symbiosis with their microbiomes, whose genetic diversity dwarfs that of humans. Symbiosis is critical and imbalances are associated with disease, occurring within hours of serious illness and injury. There are many characteristics of space flight that negatively influence the microbiome, especially deep space itself, with its increased radiation and absence of gravity. Prolonged weightlessness causes many physiologic changes that are detrimental; some resemble aging and will adversely affect the ability to tolerate critical illness or injury and subsequent treatment. Critical illness-induced intra-abdominal hypertension (IAH) may induce malperfusion of both the viscera and microbiome, with potentially catastrophic effects. Evidence from animal models confirms profound IAH effects on the gut, namely ischemia and disruption of barrier function, mechanistically linking IAH to resultant organ dysfunction. Therefore, a pathologic dysbiome, space-induced immune dysfunction and a diminished cardiorespiratory reserve with exacerbated susceptibility to IAH, imply that a space-deconditioned astronaut will be vulnerable to IAH-induced gut malperfusion. This sets the stage for severe gut ischemia and massive biomediator generation in an astronaut with reduced cardiorespiratory/immunological capacity. Fortunately, experiments in weightless analogue environments suggest that IAH may be ameliorated by conformational abdominal wall changes and a resetting of thoracoabdominal mechanics. Thus, review of the interactions of physiologic changes with prolonged weightlessness and IAH is required to identify appropriate questions for planning exploration class space surgical care.