Fluid administration for acute circulatory dysfunction using basic monitoring: narrative review and expert panel recommendations from an ESICM task force

Heart-Lungs interactions: the basics and clinical implications

Heart-lungs interactions are related to the interplay between the cardiovascular and the respiratory system. They result from the respiratory-induced changes in intrathoracic pressure, which are transmitted to the cardiac cavities and to the changes in alveolar pressure, which may impact the lung microvessels. In spontaneously breathing patients, consequences of heart-lungs interactions are during inspiration an increase in right ventricular preload and afterload, a decrease in left ventricular preload and an increase in left ventricular afterload. In mechanically ventilated patients, consequences of heart-lungs interactions are during mechanical insufflation a decrease in right ventricular preload, an increase in right ventricular afterload, an increase in left ventricular preload and a decrease in left ventricular afterload. Physiologically and during normal breathing, heart-lungs interactions do not lead to significant hemodynamic consequences. Nevertheless, in some clinical settings such as acute exacerbation of chronic obstructive pulmonary disease, acute left heart failure or acute respiratory distress syndrome, heart-lungs interactions may lead to significant hemodynamic consequences. These are linked to complex pathophysiological mechanisms, including a marked inspiratory negativity of intrathoracic pressure, a marked inspiratory increase in transpulmonary pressure and an increase in intra-abdominal pressure. The most recent application of heart-lungs interactions is the prediction of fluid responsiveness in mechanically ventilated patients. The first test to be developed using heart-lungs interactions was the respiratory variation of pulse pressure. Subsequently, many other dynamic fluid responsiveness tests using heart-lungs interactions have been developed, such as the respiratory variations of pulse contour-based stroke volume or the respiratory variations of the inferior or superior vena cava diameters. All these tests share the same limitations, the most frequent being low tidal volume ventilation, persistent spontaneous breathing activity and cardiac arrhythmia. Nevertheless, when their main limitations are properly addressed, all these tests can help intensivists in the decision-making process regarding fluid administration and fluid removal in critically ill patients.

Capillary refill time assessment after fluid challenge in patients on venoarterial extracorporeal membrane oxygenation: A retrospective study

BACKGROUND

Monitoring fluid therapy is challenging in patients assisted with Veno-arterial ECMO. The aim of our study was to evaluate the usefulness of capillary refill time to assess the response to fluid challenge in patients assisted with VA-ECMO.

METHODS

Retrospective monocentric study in a cardiac surgery ICU. We assess fluid responsiveness after a fluid challenge in patients on VA-ECMO. We recorded capillary refill time before and after fluid challenge and the evolution of global hemodynamic parameters.

RESULTS

A total of 27 patients were included. The main indications for VA-ECMO were post-cardiotomy cardiogenic shock (44%). Thirteen patients (42%) were responders and 14 non-responders (58%). In the responder group, the index CRT decreased significantly (1.7 [1.5; 2.1] vs. 1.2 [1; 1.3] s; p = 0.01), whereas it remained stable in the non-responder group (1.4 [1.1; 2.5] vs. 1.6 [0.9; 1.9] s; p = 0.22). Diagnosis performance of CRT variation to assess response after fluid challenge shows an AUC of 0.68 (p = 0.10) with a sensitivity of 79% [95% CI, 52-92] and a specificity of 69% [95% CI, 42-87], with a threshold at 23%.

CONCLUSION

In patients treated with VA-ECMO index capillary refill time is a reliable tool to assesses fluid responsiveness.

SPECIALTY

Critical care, Cardiac surgery, ECMO.

Intravenous fluid therapy compared to no treatment following blood donation in cats: a randomised controlled

OBJECTIVES

There is currently no consensus regarding the use of intravenous fluid therapy in feline patients post-blood donation in veterinary medicine. The primary aim of this study was to determine whether blood donation can be performed safely without post-donation intravenous fluid therapy. The secondary aim was to report owner-noted post-donation changes.

MATERIALS AND METHODS

The study aimed to enrol 100 conscious feline blood donations by client-owned cats performed at a veterinary teaching hospital. Donors were randomised to either receive intravenous compound sodium lactate (twice the volume of blood donated over 2 hours) immediately after blood donation, or to receive no post-blood donation intravenous fluid therapy. Systolic blood pressure was measured non-invasively at 0, 60 and 120 minutes post-donation. Median blood pressures were compared between the two groups using a Shapiro-Wilk test. Owners were called the day following the donation to collect information on changes in their cat post-donation.

RESULTS

One hundred cats were enrolled and the data of 97 cats were analysed; 46 who received intravenous fluid therapy and 51 who did not. Mean donation volume was 9.95 mL/kg for the intravenous fluid therapy group and 9.72 mL/kg for the non-intravenous fluid therapy group. At each time point, the median blood pressure did not differ significantly between the two groups. The main reported changes in both goups were bruising at the venepuncture site with 27.3% (12/44) in the IVFT group and 23.4% (9/37) in the no-IVFT group, and mild lethargy up to a maximum of 24 hours post donation with 11.4% (5/44) in the IVFT group and 18.9% (7/37) in the no-IVFT group.

CLINICAL SIGNIFICANCE

This study suggests that the use of intravenous fluid therapy post-feline blood donation may not be necessary. This could mean reduced hospitalisation time for feline donors, possibly decreasing feline stress.

Perspectives for capillary refill time in clinical practice for sepsis

BACKGROUND

Capillary refill time (CRT) is defined as the time taken for color to return to an external capillary bed after pressure is applied to cause blanching. Recent studies demonstrated the benefits of CRT in guiding fluid therapy for sepsis. However, lack of consistency among physicians in how to perform and interpret CRT has led to a low interobserver agreement for this assessment tool, which prevents its availability in sepsis clinical settings.

OBJECTIVE

To give physicians a concise overview of CRT and explore recent evidence on its reliability and value in the management of sepsis.

RESEARCH DESIGN

A narrative review.

RESULTS

This narrative review summarizes the factors affecting CRT values, for example, age, sex, temperature, light, observation techniques, work experience, training level and differences in CRT measurement methods. The methods of reducing the variability of CRT are synthesized. Based on studies with highly reproducible CRT measurements and an excellent inter-rater concordance, we recommend the standardized CRT assessment method. The threshold of normal CRT values is discussed. The application of CRT in different phases of sepsis management is summarized.

CONCLUSIONS

Recent data confirm the value of CRT in critically ill patients. CRT should be detected by trained physicians using standardized methods and reducing the effect of ambient-related factors. Its association with severe infection, microcirculation, tissue perfusion response, organ dysfunction and adverse outcomes makes this approach a very attractive tool in sepsis. Further studies should confirm its value in the management of sepsis.

IMPLICATIONS FOR CLINICAL PRACTICE

As a simple assessment, CRT deserves more attention even though it has not been widely applied at the bedside. CRT could provide nursing staff with patient's microcirculatory status, which may help to develop individualized nursing plans and improve the patient's care quality and treatment outcomes.

Use of stepwise lung recruitment maneuver to predict fluid responsiveness under lung protective ventilation in the operating room

Recent research has revealed that hemodynamic changes caused by lung recruitment maneuvers (LRM) with continuous positive airway pressure can be used to identify fluid responders. We investigated the usefulness of stepwise LRM with increasing positive end-expiratory pressure and constant driving pressure for predicting fluid responsiveness in patients under lung protective ventilation (LPV). Forty-one patients under LPV were enrolled when PPV values were in a priori considered gray zone (4% to 17%). The FloTrac-Vigileo device measured stroke volume variation (SVV) and stroke volume (SV), while the patient monitor measured pulse pressure variation (PPV) before and at the end of stepwise LRM and before and 5 min after fluid challenge (6 ml/kg). Fluid responsiveness was defined as a ≥ 15% increase in the SV or SV index. Seventeen were fluid responders. The areas under the curve for the augmented values of PPV and SVV, as well as the decrease in SV by stepwise LRM to identify fluid responders, were 0.76 (95% confidence interval, 0.61-0.88), 0.78 (0.62-0.89), and 0.69 (0.53-0.82), respectively. The optimal cut-offs for the augmented values of PPV and SVV were > 18% and > 13%, respectively. Stepwise LRM -generated augmented PPV and SVV predicted fluid responsiveness under LPV.

Are We Always Right? Evaluation of the Performance and Knowledge of the Passive Leg Raise Test in Detecting Volume Responsiveness in Critical Care Patients: A National German Survey

Background: In hemodynamically unstable patients, the passive leg raise (PLR) test is recommended for use as a self-fluid challenge for predicting preload responsiveness. However, to interpret the hemodynamic effects and reliability of the PLR, the method of performing it is of the utmost importance. Our aim was to determine the current practice of the correct application and interpretation of the PLR in intensive care patients. Methods: After ethical approval, we designed a cross-sectional online survey with a short user-friendly online questionnaire. Using a random sample of 1903 hospitals in Germany, 182 hospitals with different levels of care were invited via an email containing a link to the questionnaire. The online survey was conducted between December 2021 and January 2022. All critical care physicians from different medical disciplines were surveyed. We evaluated the correct points of concern for the PLR, including indication, contraindication, choice of initial position, how to interpret and apply the changes in cardiac output, and the limitations of the PLR. Results: A total of 292 respondents participated in the online survey, and 283/292 (97%) of the respondents completed the full survey. In addition, 132/283 (47%) were consultants and 119/283 (42%) worked at a university medical center. The question about the performance of the PLR was answered correctly by 72/283 (25%) of the participants. The limitations of the PLR, such as intra-abdominal hypertension, were correctly selected by 150/283 (53%) of the participants. The correct effect size (increase in stroke volume ≥ 10%) was correctly identified by 217/283 (77%) of the participants. Conclusions: Our results suggest a considerable disparity between the contemporary practice of the correct application and interpretation of the PLR and the practice recommendations from recently published data at German ICUs.

Critical Care Management of Patients After Cardiac Arrest: A Scientific Statement from the American Heart Association and Neurocritical Care Society

The critical care management of patients after cardiac arrest is burdened by a lack of high-quality clinical studies and the resultant lack of high-certainty evidence. This results in limited practice guideline recommendations, which may lead to uncertainty and variability in management. Critical care management is crucial in patients after cardiac arrest and affects outcome. Although guidelines address some relevant topics (including temperature control and neurological prognostication of comatose survivors, 2 topics for which there are more robust clinical studies), many important subject areas have limited or nonexistent clinical studies, leading to the absence of guidelines or low-certainty evidence. The American Heart Association Emergency Cardiovascular Care Committee and the Neurocritical Care Society collaborated to address this gap by organizing an expert consensus panel and conference. Twenty-four experienced practitioners (including physicians, nurses, pharmacists, and a respiratory therapist) from multiple medical specialties, levels, institutions, and countries made up the panel. Topics were identified and prioritized by the panel and arranged by organ system to facilitate discussion, debate, and consensus building. Statements related to postarrest management were generated, and 80% agreement was required to approve a statement. Voting was anonymous and web based. Topics addressed include neurological, cardiac, pulmonary, hematological, infectious, gastrointestinal, endocrine, and general critical care management. Areas of uncertainty, areas for which no consensus was reached, and future research directions are also included. Until high-quality studies that inform practice guidelines in these areas are available, the expert panel consensus statements that are provided can advise clinicians on the critical care management of patients after cardiac arrest.

Critical Care Management of Patients After Cardiac Arrest: A Scientific Statement From the American Heart Association and Neurocritical Care Society

The critical care management of patients after cardiac arrest is burdened by a lack of high-quality clinical studies and the resultant lack of high-certainty evidence. This results in limited practice guideline recommendations, which may lead to uncertainty and variability in management. Critical care management is crucial in patients after cardiac arrest and affects outcome. Although guidelines address some relevant topics (including temperature control and neurological prognostication of comatose survivors, 2 topics for which there are more robust clinical studies), many important subject areas have limited or nonexistent clinical studies, leading to the absence of guidelines or low-certainty evidence. The American Heart Association Emergency Cardiovascular Care Committee and the Neurocritical Care Society collaborated to address this gap by organizing an expert consensus panel and conference. Twenty-four experienced practitioners (including physicians, nurses, pharmacists, and a respiratory therapist) from multiple medical specialties, levels, institutions, and countries made up the panel. Topics were identified and prioritized by the panel and arranged by organ system to facilitate discussion, debate, and consensus building. Statements related to postarrest management were generated, and 80% agreement was required to approve a statement. Voting was anonymous and web based. Topics addressed include neurological, cardiac, pulmonary, hematological, infectious, gastrointestinal, endocrine, and general critical care management. Areas of uncertainty, areas for which no consensus was reached, and future research directions are also included. Until high-quality studies that inform practice guidelines in these areas are available, the expert panel consensus statements that are provided can advise clinicians on the critical care management of patients after cardiac arrest.

Effect on capillary refill time of volume expansion and increase of the norepinephrine dose in patients with septic shock

BACKGROUND

Capillary refill time (CRT) has been suggested as a variable to follow during the course of septic shock. We systematically investigated the effects on CRT of volume expansion and norepinephrine.

METHODS

In 69 septic shock patients, we recorded mean arterial pressure (MAP), cardiac index (CI), and 5 consecutive CRT measurements (video method, standardized pressure applied on the fingertip) before and after a 500-mL saline infusion in 33 patients and before and after an increase of the norepinephrine dose in 36 different patients. Fluid responders were defined by an increase in CI ≥ 15%, and norepinephrine responders by an increase in MAP ≥ 15%.

RESULTS

The least significant change of CRT was 23%, so that changes in CRT were considered significant if larger than 23%. With volume expansion, CRT remained unchanged on average in patients with baseline CRT < 3 s (n = 7) and in all but one patient with baseline CRT ≥ 3 s in whom fluid increased CI < 15% (n = 13 "fluid non-responders"). In fluid responders with baseline CRT ≥ 3 s (n = 13), CRT decreased in 8 patients and remained unchanged in the others, exhibiting a dissociation between CI and CRT responses. The proportion of patients included > 24 h after starting norepinephrine was higher in patients with such a dissociation than in the other ones (60% vs. 0%, respectively). Norepinephrine did not change CRT significantly (except in one patient) if baseline CRT was ≥ 3 s and the increase in MAP < 15% (n = 6). In norepinephrine responders with prolonged baseline CRT (n = 11), it increased in 4 patients and remained unchanged in the other ones, which exhibited a dissociation between MAP and CRT responses.

CONCLUSIONS

In septic shock patients with prolonged CRT, CRT very rarely improves with treatment when volume expansion increases cardiac output < 15% and increasing norepinephrine increases MAP < 15%. When the effects of fluid infusion on cardiac output and of norepinephrine on MAP are significant, the response of CRT is variable, as it decreases in some patients and remains stable in others which exhibit a dissociation between changes in macrohemodynamic variables and in CRT. In this regard, CRT behaves as a marker of microcirculation.

TRIAL REGISTRATION

ClinicalTrial.gov (NCT04870892). Registered January15, 2021. Ethics committee approval CE SRLF 21-25.

Ultrasonographic measurement of caudal vena cava to aorta ratio during fluid resuscitation of dogs with spontaneous circulatory shock

OBJECTIVES

To describe the change in the caudal vena cava to aorta ratio (CVC:Ao) ratio during fluid resuscitation of circulatory shock in dogs and compare these results with those of the physical examination and blood lactate.

MATERIALS AND METHODS

Perfusion parameters and blood lactate were recorded at admission. An abdominal point-of-care ultrasound protocol was performed, during which the caudal vena cava to aorta ratio was measured on the spleno-renal view. Measurements were performed within 5 minutes before and after a 10 mL/kg crystalloid fluid bolus. Investigators were not blinded to therapeutic interventions.

RESULTS

Twenty-nine dogs with physical signs of circulatory shock were enrolled. Caudal vena cava to aorta ratios were below reference interval in 28 of 29 dogs. After bolus administration, median caudal vena cava diameter increased by 0.14 cm (0.69 to 0.83 cm) and median aorta diameter increased by 0.03 cm (0.87 to 0.90 cm) and caudal vena cava to aorta ratio returned to within reference range in 65% of dogs (13/29). Bolus administration was associated with an increase in median caudal vena cava to aorta ratio of 0.10 (95% CI:0.05 to 0.16, P=0.0005). Blood lactate did not change significantly. Heart rate and capillary refill time decreased significantly after fluid bolus (heart rate: estimate=-19 bpm, 95% CI:-30 to -8, P=0.002; capillary refill time: estimate=-1.0 s, 95% CI:-1.3 to -0.7, P < 0.0001).

CLINICAL SIGNIFICANCE

In this population of dogs with circulatory shock, the caudal vena cava to aorta ratio significantly increased after a fluid bolus. Future studies that implement blinding of the outcome assessors are warranted to confirm these findings.

Association between diastolic blood pressure during the first 24 h and 28-day mortality in patients with septic shock: a retrospective observational study

BACKGROUND

Although the mean arterial pressure (MAP) target of 65 mmHg was achieved, diastolic blood pressure (DBP) was still low in some septic shock patients. The effects of DBP on the prognosis and optimal target for patients with septic shock are unclear. We sought to investigate the relationship between DBP and 28-day mortality in septic shock patients.

METHODS

In this retrospective observational study, we obtained data from the Chinese Database in Intensive Care (CDIC). We included patients with an admission diagnosis of septic shock and shock was controlled. DBP was measured every 1 h, and the mean DBP during the first 24 h (mDBP24h) was recorded. The primary outcome was 28-day mortality. Multivariable logistic regression determined the relationship between mDBP24h and 28-day mortality.

RESULTS

In total, 1251 patients were finally included. The 28-day mortality of included septic shock patients was 28.3%. The mDBP24h, not mSBP24h, was higher among 28-day survivors compared with non-survivors. 28-day mortality was inversely associated with mDBP24h (unadjusted OR 0.814 per 10 mmHg higher mDBP24h, P = 0.003), with a stepwise increase in 28-day mortality at lower mDBP24h. The 28-day mortality of patients with mDBP24h < 59 mmHg had an absolute risk reduction of 9.4% (P = 0.001). And mDBP24h < 59 mmHg was the remaining high risk factor inversely associated with 28-day mortality after multivariable adjustment (adjusted OR 1.915, 95% CI 1.037-3.536, P = 0.038), while mMAP24h and mSBP24h were not.

CONCLUSION

In patients with septic shock after initial resuscitation, we observed an inverse association between mDBP24h and 28-day mortality. The poor outcomes in patients with mDBP24h < 59 mmHg provide indirect evidence supporting a further DBP goal of 59 mmHg for patients with septic shock after MAP of 65 mmHg was achieved.

Hemodynamic management of septic shock: beyond the Surviving Sepsis Campaign guidelines

Although the Surviving Sepsis Campaign guidelines provide standardized and generalized guidance, they are less individualized. This review focuses on recent updates in the hemodynamic management of septic shock. Monitoring and intervention for septic shock should be personalized according to the phase of shock. In the salvage phase, fluid resuscitation and vasopressors should be given to provide life-saving tissue perfusion. During the optimization phase, tissue perfusion should be optimized. In the stabilization and de-escalation phases, minimal fluid infusion and safe fluid removal should be performed, respectively, while preserving organ perfusion. There is controversy surrounding the use of restrictive versus liberal fluid strategies after initial resuscitation. Fluid administration after initial resuscitation should depend upon the patient's fluid responsiveness and requires individualized management. A number of dynamic tests have been proposed to monitor fluid responsiveness, which can help clinicians decide whether to give fluid or not. The optimal timing for the initiation of vasopressor agents is unknown. Recent data suggest that early vasopressor initiation should be considered. Inotropes can be considered in patients with decreased cardiac contractility associated with impaired tissue perfusion despite adequate volume status and arterial blood pressure. Venoarterial extracorporeal membrane oxygenation should be considered for refractory septic shock with severe cardiac systolic dysfunction.

Society for Maternal-Fetal Medicine Consult Series #67: Maternal sepsis

Maternal sepsis is a significant cause of maternal morbidity and mortality, and is a potentially preventable cause of maternal death. This Consult aims to summarize what is known about sepsis and provide guidance for the management of sepsis during pregnancy and the postpartum period. Most studies cited are from the nonpregnant population, but where available, pregnancy data are included. The following are the Society for Maternal-Fetal Medicine recommendations: (1) we recommend that clinicians consider the diagnosis of sepsis in pregnant or postpartum patients with otherwise unexplained end-organ damage in the presence of a suspected or confirmed infectious process, regardless of the presence of fever (GRADE 1C); (2) we recommend that sepsis and septic shock in pregnancy be considered medical emergencies and that treatment and resuscitation begin immediately (Best Practice); (3) we recommend that hospitals and health systems use a performance improvement program for sepsis in pregnancy with sepsis screening tools and metrics (GRADE 1B); (4) we recommend that institutions develop their own procedures and protocols for the detection of maternal sepsis, avoiding the use of a single screening tool alone (GRADE 1B); (5) we recommend obtaining tests to evaluate for infectious and noninfectious causes of life-threatening organ dysfunction in pregnant and postpartum patients with possible sepsis (Best Practice); (6) we recommend that an evaluation for infectious causes in pregnant or postpartum patients in whom sepsis is suspected or identified includes appropriate microbiologic cultures, including blood, before starting antimicrobial therapy, as long as there are no substantial delays in timely administration of antibiotics (Best Practice); (7) we recommend obtaining a serum lactate level in pregnant or postpartum patients in whom sepsis is suspected or identified (GRADE 1B); (8) in pregnant or postpartum patients with septic shock or a high likelihood of sepsis, we recommend administration of empiric broad-spectrum antimicrobial therapy, ideally within 1 hour of recognition (GRADE 1C); (9) after a diagnosis of sepsis in pregnancy is made, we recommend rapid identification or exclusion of an anatomic source of infection and emergency source control when indicated (Best Practice); (10) we recommend early intravenous administration (within the first 3 hours) of 1 to 2 L of balanced crystalloid solutions in sepsis complicated by hypotension or suspected organ hypoperfusion (GRADE 1C); (11) we recommend the use of a balanced crystalloid solution as a first-line fluid for resuscitation in pregnant and postpartum patients with sepsis or septic shock (GRADE 1B); (12) we recommend against the use of starches or gelatin for resuscitation in pregnant and postpartum patients with sepsis or septic shock (GRADE 1A); (13) we recommend ongoing, detailed evaluation of the patient's response to fluid resuscitation guided by dynamic measures of preload (GRADE 1B); (14) we recommend the use of norepinephrine as the first-line vasopressor during pregnancy and the postpartum period with septic shock (GRADE 1C); (15) we suggest using intravenous corticosteroids in pregnant or postpartum patients with septic shock who continue to require vasopressor therapy (GRADE 2B); (16) because of an increased risk of venous thromboembolism in sepsis and septic shock, we recommend the use of pharmacologic venous thromboembolism prophylaxis in pregnant and postpartum patients in septic shock (GRADE 1B); (17) we suggest initiating insulin therapy at a glucose level >180 mg/dL in critically ill pregnant patients with sepsis (GRADE 2C); (18) if a uterine source for sepsis is suspected or confirmed, we recommend prompt delivery or evacuation of uterine contents to achieve source control, regardless of gestational age (GRADE 1C); and (19) because of an increased risk of physical, cognitive, and emotional problems in survivors of sepsis and septic shock, we recommend ongoing comprehensive support for pregnant and postpartum sepsis survivors and their families (Best Practice).

Simultaneous venous-arterial Doppler during preload augmentation: illustrating the Doppler Starling curve

Providing intravenous (IV) fluids to a patient with signs or symptoms of hypoperfusion is common. However, evaluating the IV fluid 'dose-response' curve of the heart is elusive. Two patients were studied in the emergency department with a wireless, wearable Doppler ultrasound system. Change in the common carotid arterial and internal jugular Doppler spectrograms were simultaneously obtained as surrogates of left ventricular stroke volume (SV) and central venous pressure (CVP), respectively. Both patients initially had low CVP jugular venous Doppler spectrograms. With preload augmentation, only one patient had arterial Doppler measures indicative of significant SV augmentation (i.e., 'fluid responsive'). The other patient manifested diminishing arterial response, suggesting depressed SV (i.e., 'fluid unresponsive') with evidence of ventricular asynchrony. In this short communication, we describe how a wireless, wearable Doppler ultrasound simultaneously tracks surrogates of cardiac preload and output within a 'Doppler Starling curve' framework; implications for IV fluid dosing are discussed.

Evolving Management Practices for Early Sepsis-induced Hypoperfusion: A Narrative Review

Sepsis causes significant morbidity and mortality worldwide. Resuscitation is a cornerstone of management. This review covers five areas of evolving practice in the management of early sepsis-induced hypoperfusion: fluid resuscitation volume, timing of vasopressor initiation, resuscitation targets, route of vasopressor administration, and use of invasive blood pressure monitoring. For each topic, we review the seminal evidence, discuss the evolution of practice over time, and highlight questions for additional research. Intravenous fluids are a core component of early sepsis resuscitation. However, with growing concerns about the harms of fluid, practice is evolving toward smaller-volume resuscitation, which is often paired with earlier vasopressor initiation. Large trials of fluid-restrictive, vasopressor-early strategies are providing more information about the safety and potential benefit of these approaches. Lowering blood pressure targets is a means to prevent fluid overload and reduce exposure to vasopressors; mean arterial pressure targets of 60-65 mm Hg appear to be safe, at least in older patients. With the trend toward earlier vasopressor initiation, the need for central administration of vasopressors has been questioned, and peripheral vasopressor use is increasing, although it is not universally accepted. Similarly, although guidelines suggest the use of invasive blood pressure monitoring with arterial catheters in patients receiving vasopressors, blood pressure cuffs are less invasive and often sufficient. Overall, the management of early sepsis-induced hypoperfusion is evolving toward fluid-sparing and less-invasive strategies. However, many questions remain, and additional data are needed to further optimize our approach to resuscitation.

Standardized blood volume changes monitored by capnodynamic hemodynamic variables: An experimental comparative study in pigs

BACKGROUND

The capnodynamic method, based on Volumetric capnography and differential Fick mathematics, assess cardiac output in mechanically ventilated subjects. Capnodynamic and established hemodynamic monitoring parameters' capability to depict alterations in blood volume were investigated in a model of standardized hemorrhage, followed by crystalloid and blood transfusion.

METHODS

Ten anesthetized piglets were subjected to controlled hemorrhage (450 mL), followed by isovolemic crystalloid bolus and blood re-transfusion. Intravascular blood volume, and all hemodynamic variables, were determined twice after each intervention. The investigated hemodynamic variables were: cardiac output and stroke volume for capnodynamics and pulse contour analysis, respectively, pulse pressure and stroke volume variability and mean arterial pressure. One-way ANOVA and Tukey's test for multiple comparisons were used to identify significant changes. Trending was assessed by correlation and concordance.

RESULT

Concordance against intravascular volume changes for capnodynamic cardiac output and stroke volume were 96 and 94%, with correlations r = .78 and .68, (p < .0001) with significant changes for 6 and 5 of the 6 measuring points, respectively. Mean arterial pressure and pulse pressure variation had a concordance of 85% and 87%, r = .67 (p < .0001) and r = -.45 (p < .0001), respectively, and both changed significantly for 3 of 6 measuring points. Pulse contour stroke volume variation, stroke volume and cardiac output, showed concordance and correlation of 76%, r = -.18 (p = .11), 63%, r = .28 (p = .01) and 50%, r = .31 (p = .007), respectively and significant change for 1, 1 and 0 of the measuring points, respectively.

CONCLUSION

Capnodynamic cardiac output and stroke volume did best depict the changes in intravascular blood volume. Pulse contour parameters did not follow volume changes in a reliable way.

THE EFFECTS OF EARLY-PHASE FUROSEMIDE USE ON THE PROGRESSION OF OLIGURIC ACUTE KIDNEY INJURY ACROSS DIFFERENT CENTRAL VENOUS PRESSURE: A RETROSPECTIVE ANALYSIS

ABSTRACT

Background: Furosemide is a commonly used loop diuretic in critical care. However, its effect on the progression of oliguric acute kidney injury across different central venous pressure (CVP) remains unknown. This study therefore aims to investigate the association between furosemide 6-12h (defined as the use of furosemide within 6 h after the diagnosis of AKI according to the urine output [UO] criteria set by the Kidney Disease: Improving Global Outcomes [KDIGO] guidelines) and the progression of AKI across different CVP 6-12h (defined as CVP within 6 h after the diagnosis of AKI by the KDIGO UO criteria) levels. Methods: Patients involved in this study were identified from the Medical Information Mart for Intensive Care IV database with the following criteria: (i) adults with UO <0.5 mL/kg per hour for the first 6 h upon admission to the intensive care unit (ICU) (meeting stage 1 AKI by UO) and (ii) CVP 6-12h ranging from 0 to 30 mm Hg. From there on, the target primary outcome would be progression to stage 3 AKI by UO among these chosen patients. The secondary outcome was 28-d mortality since ICU admission. The risks of severe-stage AKI progression and 28-d mortality were respectively examined against furosemide 6-12h (vs. without furosemide 6-12h ) within the full cohort and across different subgroups of CVP 6-12h , using multivariate adjusted logistic regression and inverse probability treatment weighting (IPTW). Sensitivity analyses were performed to assess the robustness of our findings. Results: One thousand one hundred eighty patients were ultimately selected for this study, of whom 643 (54.5%) progressed to stage 3 AKI from stage 1 based on the UO criteria by KDIGO. Multivariate analysis showed that furosemide 6-12h is significantly associated with this severe-stage progression within the full cohort (odds ratio [OR] was 0.62 at 95% confidence interval [CI] of 0.43-0.90, P = 0.011). After dividing the patients into CVP 6-12h subgroups according to their CVP during the early phases, lower risk of AKI progression was observed only in furosemide 6-12h application at CVP 6-12h of ≥12 mm Hg (adjusted OR was 0.40 at 95% CI of 0.25-0.65, P < 0.001), as confirmed by the IPTW analysis (OR was 0.47 at 95% CI of 0.29-0.76, P = 0.002). The robustness of these findings was confirmed by sensitivity analyses. In addition, for patients with CVP 6-12h ≥12 mm Hg, furosemide 6-12h is also significantly associated with lower risk of 28-d mortality (adjusted OR was 0.47 at 95% CI of 0.25-0.92, P = 0.026) in the multivariate logistic regression analysis, and there was a similar trend in the IPTW analysis (adjusted OR was 0.55 at 95% CI of 0.28-1.10, P = 0.092). Conclusions: Among the identified early-stage AKI patients in critical care, the use of furosemide was associated only with lower risk of oliguric AKI progression and 28-d mortality within the high CVP group. These findings suggest the potential of CVP as a guidance or reference point in the usage of furosemide among early-stage oliguric AKI patients in the ICU.

A plea for personalization of the hemodynamic management of septic shock

Although guidelines provide excellent expert guidance for managing patients with septic shock, they leave room for personalization according to patients' condition. Hemodynamic monitoring depends on the evolution phase: salvage, optimization, stabilization, and de-escalation. Initially during the salvage phase, monitoring to identify shock etiology and severity should include arterial pressure and lactate measurements together with clinical examination, particularly skin mottling and capillary refill time. Low diastolic blood pressure may trigger vasopressor initiation. At this stage, echocardiography may be useful to identify significant cardiac dysfunction. During the optimization phase, echocardiographic monitoring should be pursued and completed by the assessment of tissue perfusion through central or mixed-venous oxygen saturation, lactate, and carbon dioxide veno-arterial gradient. Transpulmonary thermodilution and the pulmonary artery catheter should be considered in the most severe patients. Fluid therapy also depends on shock phases. While administered liberally during the resuscitation phase, fluid responsiveness should be assessed during the optimization phase. During stabilization, fluid infusion should be minimized. In the de-escalation phase, safe fluid withdrawal could be achieved by ensuring tissue perfusion is preserved. Norepinephrine is recommended as first-line vasopressor therapy, while vasopressin may be preferred in some patients. Essential questions remain regarding optimal vasopressor selection, combination therapy, and the most effective and safest escalation. Serum renin and the angiotensin I/II ratio may identify patients who benefit most from angiotensin II. The optimal therapeutic strategy for shock requiring high-dose vasopressors is scant. In all cases, vasopressor therapy should be individualized, based on clinical evaluation and blood flow measurements to avoid excessive vasoconstriction. Inotropes should be considered in patients with decreased cardiac contractility associated with impaired tissue perfusion. Based on pharmacologic properties, we suggest as the first test a limited dose of dobutamine, to add enoximone or milrinone in the second line and substitute or add levosimendan if inefficient. Regarding adjunctive therapies, while hydrocortisone is nowadays advised in patients receiving high doses of vasopressors, patients responding to corticosteroids may be identified in the future by the analysis of selected cytokines or specific transcriptomic endotypes. To conclude, although some general rules apply for shock management, a personalized approach should be considered for hemodynamic monitoring and support.

Tidal volume challenge to predict preload responsiveness in patients with acute respiratory distress syndrome under prone position

Background

Prone position is frequently used in patients with acute respiratory distress syndrome (ARDS), especially during the Coronavirus disease 2019 pandemic. Our study investigated the ability of pulse pressure variation (PPV) and its changes during a tidal volume challenge (TVC) to assess preload responsiveness in ARDS patients under prone position.

Methods

This was a prospective study conducted in a 25-bed intensive care unit at a university hospital. We included patients with ARDS under prone position, ventilated with 6 mL/kg tidal volume and monitored by a transpulmonary thermodilution device. We measured PPV and its changes during a TVC (ΔPPV TVC6–8) after increasing the tidal volume from 6 to 8 mL/kg for one minute. Changes in cardiac index (CI) during a Trendelenburg maneuver (ΔCITREND) and during end-expiratory occlusion (EEO) at 8 mL/kg tidal volume (ΔCI EEO8) were recorded. Preload responsiveness was defined by both ΔCITREND ≥ 8% and ΔCI EEO8 ≥ 5%. Preload unresponsiveness was defined by both ΔCITREND < 8% and ΔCI EEO8 < 5%.

Results

Eighty-four sets of measurements were analyzed in 58 patients. Before prone positioning, the ratio of partial pressure of arterial oxygen to fraction of inspired oxygen was 104 ± 27 mmHg. At the inclusion time, patients were under prone position for 11 (2–14) hours. Norepinephrine was administered in 83% of cases with a dose of 0.25 (0.15–0.42) µg/kg/min. The positive end-expiratory pressure was 14 (11–16) cmH2O. The driving pressure was 12 (10–17) cmH2O, and the respiratory system compliance was 32 (22–40) mL/cmH2O. Preload responsiveness was detected in 42 cases. An absolute change in PPV ≥ 3.5% during a TVC assessed preload responsiveness with an area under the receiver operating characteristics (AUROC) curve of 0.94 ± 0.03 (sensitivity: 98%, specificity: 86%) better than that of baseline PPV (0.85 ± 0.05; p = 0.047). In the 56 cases where baseline PPV was inconclusive (≥ 4% and < 11%), ΔPPV TVC6–8 ≥ 3.5% still enabled to reliably assess preload responsiveness (AUROC: 0.91 ± 0.05, sensitivity: 97%, specificity: 81%; p < 0.01 vs. baseline PPV).

Conclusion

In patients with ARDS under low tidal volume ventilation during prone position, the changes in PPV during a TVC can reliably assess preload responsiveness without the need for cardiac output measurements.

Trial registration: ClinicalTrials.gov (NCT04457739). Registered 30 June 2020 —Retrospectively registered, https://clinicaltrials.gov/ct2/show/record/NCT04457739

Clinical presentation and outcomes of acute heart failure in the critically ill patient: A prospective, observational, multicentre study

AIMS

To assess the clinical profile and factors associated with 30-day mortality in patients with acute heart failure (AHF) admitted to the intensive care unit (ICU).

DESIGN

Prospective, multicentre cohort study.

SCOPE

Thirty-two Spanish ICUs.

PATIENTS

Adult patients admitted to the ICU between April and June 2017.

INTERVENTION

Patients were classified into three groups according to AHF status: without AHF (no AHF); AHF as the primary reason for ICU admission (primary AHF); and AHF developed during the ICU stay (secondary AHF).

MAIN VARIABLES OF INTEREST

Incidence of AHF and 30-day mortality.

RESULTS

A total of 4330 patients were included. Of these, 627 patients (14.5%) had primary (n=319; 7.4%) or secondary (n=308; 7.1%) AHF. Among the main precipitating factors, fluid overload was more common in the secondary AHF group than in the primary group (12.9% vs 23.4%, p<0.001). Patients with AHF had a higher risk of 30-day mortality than those without AHF (OR 2.45; 95% CI: 1.93-3.11). APACHE II, cardiogenic shock, left ventricular ejection fraction, early inotropic therapy, and diagnostic delay were independently associated with 30-day mortality in AHF patients. Diagnostic delay was associated with a significant increase in 30-day mortality in the secondary group (OR 6.82; 95% CI 3.31-14.04).

CONCLUSIONS

The incidence of primary and secondary AHF was similar in this cohort of ICU patients. The risk of developing AHF in ICU patients can be reduced by avoiding modifiable precipitating factors, particularly fluid overload. Diagnostic delay was associated with significantly higher mortality rates in patients with secondary AHF.

Ultrasonographically derived caudal vena cava parameters acquired in a standing position and lateral recumbency in healthy, lightly sedated cats: a pilot study

OBJECTIVES

The aim of this study was to determine the feasibility of ultrasonographically measuring the caudal vena cava (CVC) at the subxiphoid view of healthy, lightly sedated cats in a standing position and lateral recumbency.

METHODS

This was a prospective, observational, experimental single-centre study. Twenty healthy research-purposed cats were enrolled. Two trained operators scanned each cat in two positions - standing and lateral recumbency - in a randomised order. CVC diameter was measured at the narrowest diameter during inspiration and at the widest diameter during expiration, at two anatomical locations along the CVC - where the CVC crosses the diaphragm (base) and 2 mm caudal to the diaphragm. The CVC collapsibility index (CVC-CI) was calculated for each site. Normalcy was assessed with a Shapiro-Wilk test. A one-way ANOVA with post-hoc Tukey's test was used to compare inspiratory with expiratory values within and between groups. A paired t-test compared the CVC-CI between groups (P ⩽0.05 indicated statistical significance). Spearman's correlation and Bland-Altman analysis assessed inter-operator variability.

RESULTS

All ultrasonographic data passed normalcy and were reported as mean ± SD. When compared with each other, inspiratory and expiratory values were statistically different for position, location and operator (all P <0.0001). There was no statistically significant difference between lateral recumbency or standing position for inspiratory, expiratory and CVC-CI values. Inter-operator variability was substantial, with operator 2 consistently obtaining smaller measurements than operator 1. The mean CVC-CI in lateral recumbency at the base was 24% for operator 1 and 37% for operator 2. For the same site in standing position, CVC-CI was 27% and 41% for operators 1 and 2, respectively.

CONCLUSIONS AND RELEVANCE

This pilot study demonstrates that it is possible to ultrasonographically measure the CVC diameter in both lateral recumbency and a standing position in healthy, lightly sedated cats. However, measurements obtained are operator dependent with variability between individuals. Further studies are needed to determine if ultrasonographic CVC assessment will prove helpful in estimating intravascular volume status in cats.

Passive leg raising-induced changes in pulse pressure variation to assess fluid responsiveness in mechanically ventilated patients: a multicentre prospective observational study

BACKGROUND

Passive leg raising-induced changes in cardiac index can be used to predict fluid responsiveness. We investigated whether passive leg raising-induced changes in pulse pressure variation (ΔPPV_PLR) can also predict fluid responsiveness in mechanically ventilated patients.

METHODS

In this multicentre prospective observational study, we included 270 critically ill patients on mechanical ventilation in whom volume expansion was indicated because of acute circulatory failure. We did not include patients with cardiac arrythmias. Cardiac index and PPV were measured before/during a passive leg raising test and before/after volume expansion. A volume expansion-induced increase in cardiac index of >15% defined fluid responsiveness. To investigate whether ΔPPV_PLR can predict fluid responsiveness, we determined areas under the receiver operating characteristic curves (AUROCs) and grey zones for relative and absolute ΔPPV_PLR.

RESULTS

Of the 270 patients, 238 (88%) were on controlled mechanical ventilation with no spontaneous breathing activity and 32 (12%) were on pressure support ventilation. The median tidal volume was 7.1 (inter-quartile range [IQR], 6.6-7.6) ml kg^-1 ideal body weight. One hundred sixty-four patients (61%) were fluid responders. Relative and absolute ΔPPV_PLR predicted fluid responsiveness with an AUROC of 0.92 (95% confidence interval [95% CI], 0.88-0.95; P<0.001) each. The grey zone for relative and absolute ΔPPV_PLR included 4.8% and 22.6% of patients, respectively. These results were not affected by ventilatory mode and baseline characteristics (type of shock, centre, vasoactive treatment).

CONCLUSIONS

Passive leg raising-induced changes in pulse pressure variation accurately predict fluid responsiveness with a small grey zone in critically ill patients on mechanical ventilation.

CLINICAL TRIAL REGISTRATION

NCT03225378.

Contemporary Review of Hemodynamic Monitoring in the Critical Care Setting

Hemodynamic assessment remains the most valuable adjunct to physical examination and laboratory assessment in the diagnosis and management of shock. Through the years, multiple modalities to measure and trend hemodynamic indices have evolved with varying degrees of invasiveness. Pulmonary artery catheter (PAC) has long been considered the gold standard of hemodynamic assessment in critically ill patients and in recent years has been shown to improve clinical outcomes among patients in cardiogenic shock. The invasive nature of PAC is often cited as its major limitation and has encouraged development of less invasive technologies. In this review, the authors summarize the literature on the mechanism and validation of several minimally invasive and noninvasive modalities available in the contemporary intensive care unit. They also provide an update on the use of focused bedside echocardiography.

Pathophysiology, mechanisms, and managements of tissue hypoxia

Oxygen is needed to generate aerobic adenosine triphosphate and energy that is required to support vital cellular functions. Oxygen delivery (DO₂) to the tissues is determined by convective and diffusive processes. The ability of the body to adjust oxygen extraction (ERO₂) in response to changes in DO₂ is crucial to maintain constant tissue oxygen consumption (VO₂). The capability to increase ERO₂ is the result of the regulation of the circulation and the effects of the simultaneous activation of both central and local factors. The endothelium plays a crucial role in matching tissue oxygen supply to demand in situations of acute drop in tissue oxygenation. Tissue oxygenation is adequate when tissue oxygen demand is met. When DO₂ is severely compromised, a critical DO₂ value is reached below which VO₂ falls and becomes dependent on DO₂, resulting in tissue hypoxia. The different mechanisms of tissue hypoxia are circulatory, anaemic, and hypoxic, characterised by a diminished DO₂ but preserved capacity of increasing ERO₂. Cytopathic hypoxia is another mechanism of tissue hypoxia that is due to impairment in mitochondrial respiration that can be observed in septic conditions with normal overall DO₂. Sepsis induces microcirculatory alterations with decreased functional capillary density, increased number of stopped-flow capillaries, and marked heterogeneity between the areas with large intercapillary distance, resulting in impairment of the tissue to extract oxygen and to satisfy the increased tissue oxygen demand, leading to the development of tissue hypoxia. Different therapeutic approaches exist to increase DO₂ and improve microcirculation, such as fluid therapy, transfusion, vasopressors, inotropes, and vasodilators. However, the effects of these agents on microcirculation are quite variable.

[Resuscitation strategy for patients with sepsis and septic shock]

Fluid and vasopressor resuscitation is, along with antimicrobial therapy and control of the focus of infection, a basic issue of the treatment of sepsis and septic shock. There is currently no accepted protocol that we can follow for the resuscitation of these patients and the Surviving Sepsis Campaign proposes controversial measures and without sufficient evidence support to establish firm recommendations. We propose a resuscitation strategy adapted to the situation of each patient: in the patient in whom community sepsis is suspected, we consider that the early administration of 30mL/kg of crystalloids is effective and safe; in the patient with nosocomial sepsis, we must carry out a more in-depth evaluation before initiating aggressive resuscitation. In patients who do not respond to initial resuscitation, it is necessary to increase monitoring level and, depending on the hemodynamic profile, administer more fluids, a second vasopressor or inotropes.

Capillary Refill Technology to Enhance the Accuracy of Peripheral Perfusion Evaluation in Sepsis

Background: Monitoring of capillary refill time (CRT) is a common bedside assessment used to ascertain peripheral perfusion in a patient for a vast array of conditions. The literature has shown that a change in CRT can be used to recognize life-threatening conditions that cause decreased perfusion, such as sepsis, and aid in resuscitation. The current practice for calculating CRT invites subjectivity and produces a highly variable result. Innovative technology may be able to standardize this process and provide a reliable and accurate value for use in diagnostics and treatment. This study aimed to assess a new technology (DCR by ProMedix Inc.) for rapid, bedside, and noninvasive detection of CRT. Methods: This was a secondary analysis of a prospective observational study evaluating the accuracy of new technology towards CRT-guided diagnosis of sepsis. It was carried out in the adult emergency departments (ED) of an academic tertiary care medical center. Patients seeking care in the ED were determined eligible if they were > 18 years in age and exhibited chief complaints suggestive of possible sepsis. The CRT produced by the technology was compared to the gold standard manual waveform assessment. Results: 218 consecutive subject enrollments were included and multiple measurements were made on each patient. Data with irregular waveforms were excluded. A total of 692 waveforms were evaluated for CRT values by a pair of trained PhD biomedical engineers. The average age of the cohort was 50.62 and 51.4% female. Results showed a Pearson correlation coefficient of 0.91 for the device CRT compared to the CRT gold standard. The Pearson correlation coefficient for the two independent engineering review of the waveform data was 0.98. This device produces accurate, consistent results and eliminates the subjectivity of CRT measurements that is in practice currently.

New avenues of sepsis research: obtaining perspective by analyzing and comparing SSCG 2021 and J-SSCG 2020

Recently, revisions of two sepsis guidelines, namely, the Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 and the Surviving Sepsis Campaign Guidelines 2021, were published. Although both guidelines were created in accordance with the Grading of Recommendations, Assessment, Development and Evaluation approach, the evidence-to-decision tables differed between them. In addition, certain recommendations may differ between these guidelines for similar clinical questions because of differences in the “PICO” criteria. Other differences in recommendations between the two guidelines are due to unclear evidence, and these ambiguities may provide the basis for further sepsis research. We hope that these two guidelines will contribute to the creation of new clinical evidence in addition to supporting treatment of patients with sepsis.

Enhancing sepsis management through machine learning techniques: A review

Sepsis is a major public health problem and a leading cause of death in the world, where delay in the beginning of treatment, along with clinical guidelines non-adherence have been proved to be associated with higher mortality. Machine Learning is increasingly being adopted in developing innovative Clinical Decision Support Systems in many areas of medicine, showing a great potential for automatic prediction of diverse patient conditions, as well as assistance in clinical decision making. In this context, this work conducts a narrative review to provide an overview of how specific Machine Learning techniques can be used to improve sepsis management, discussing the main tasks addressed, the most popular methods and techniques, as well as the obtained results, in terms of both intelligent system accuracy and clinical outcomes improvement.

Accuracy of cumulative volumes of fluid challenge to assess fluid responsiveness in critically ill patients with acute circulatory failure: a pharmacodynamic approach

BACKGROUND

The relationship between the dose (volume of fluid) and the effect (increase of stroke volume [SV]) has been poorly described. We hypothesised that the analysis of the dynamic response of SV during fluid challenge (FC) helps to determine the optimal volume of FC, along with its diagnostic accuracy parameters for fluid responsiveness.

METHODS

A prospective observational study was conducted in critically ill patients with circulatory failure. Patients monitored with oesophageal Doppler and assigned to an FC of 500 ml of crystalloid were included. The areas under the curve (AUC) and 95% confidence intervals (CI₉₅) of the receiver operating characteristic curves for cumulative volumes from 50 to 450 ml were determined for fluid responsiveness (SV increase ≥15% from baseline) along with other parameters of diagnostic accuracy. In the pharmacodynamic analysis, dose-effect and dose-response models were constructed, with determination of median and 90% effective dose (ED₅₀ and ED₉₀).

RESULTS

Forty-five patients were included. The AUC increased with cumulative volumes of FC up to 250 ml (AUC₂₅₀ 0.93 [CI₉₅: 0.85-1.00]), followed by a plateau above 0.95 of AUC. The optimal volume was 250 ml, associated with a specificity of 0.89 [CI₉₅: 0.78-1.00], a sensitivity of 0.92 [CI₉₅: 0.69-1.00], and a threshold of 9.6% increase in SV. The ED₅₀ was 156 [CI₉₅: 136-177] ml and the ED₉₀ was 312 [CI₉₅: 269-352] ml.

CONCLUSIONS

A volume of FC of 250 ml with a threshold of 9.6% increase in SV showed the highest accuracy in detecting fluid responsiveness in critically ill patients with shock.

CLINICAL TRIAL REGISTRATION

.

Does the definition of fluid responsiveness affect passive leg raising reliability? A methodological ancillary analysis from a multicentric study

BACKGROUND

Fluid challenge (FC) is often adopted as gold standard used to assess the reliability of passive leg raising (PLR) in predicting fluid responsiveness in the intensive care unit (ICU). This study aimed to address the impact of the different definitions and timings used to assess FC response on PLR reliability.

METHODS

Ancillary study from a data set of a multicentric study in 85 ICU patient with acute circulatory failure who received a FC (500 mL of crystalloids in 10 minutes) within the first 48h of ICU admission, preceded by PLR in 30 patients. FC response was assessed considering the changes in cardiac index (CI) and stroke volume index (SVI) using different thresholds and at different timepoints.

RESULTS

The definitions of fluid responsiveness by using CI or SVI with a 15% increase after 10 minutes were associated to the best performances of the PLR [AUC (95% CI) 0.94 (0.83-1.01); vs. AUC (95% CI) 0.95 (0.87-1.02)]. The sensitivity of the PLR by adopting the CI or the SVI as reference variable ranged from 54.1% to 67.6% and from 81.5% to 100.0%; the specificity from 65.9% to 78.0% and from 79.5% to 100.0%, respectively. Considering all the subgroups, the number of responders 10 minutes after FC administration was higher as compared to 15 and 30 minutes (140 vs. 120 and 125, respectively, p < 0.05).

CONCLUSIONS

The reliability of the PLR test to predict fluid responsiveness depends on the definition of FC adopted. The timing of FC outcome assessment affected the overall fluid responsiveness.

Left ventricular longitudinal strain variations assessed by speckle-tracking echocardiography after a passive leg raising maneuver in patients with acute circulatory failure to predict fluid responsiveness: A prospective, observational study

Background

An association was reported between the left ventricular longitudinal strain (LV-LS) and preload. LV-LS reflects the left cardiac function curve as it is the ratio of shortening over diastolic dimension. The aim of this study was to determine the sensitivity and specificity of LV-LS variations after a passive leg raising (PLR) maneuver to predict fluid responsiveness in intensive care unit (ICU) patients with acute circulatory failure (ACF).

Methods

Patients with ACF were prospectively included. Preload-dependency was defined as a velocity time integral (VTI) variation greater than 10% between baseline (T0) and PLR (T1), distinguishing the preload-dependent (PLD+) group and the preload-independent (PLD-) group. A 7-cycles, 4-chamber echocardiography loop was registered at T0 and T1, and strain analysis was performed off-line by a blind clinician. A general linear model for repeated measures was used to compare the LV-LS variation (T0 to T1) between the two groups.

Results

From June 2018 to August 2019, 60 patients (PLD+ = 33, PLD- = 27) were consecutively enrolled. The VTI variations after PLR were +21% (±8) in the PLD+ group and -1% (±7) in the PLD- group (p<0.01). Mean baseline LV-LS was -11.3% (±4.2) in the PLD+ group and -13.0% (±4.2) in the PLD- group (p = 0.12). LV-LS increased in the whole population after PLR +16.0% (±4.0) (p = 0.04). The LV-LS variations after PLR were +19.0% (±31) (p = 0.05) in the PLD+ group and +11.0% (±38) (p = 0.25) in the PLD- group, with no significant difference between the two groups (p = 0.08). The area under the curve for the LV-LS variations between T0 and T1 was 0.63 [0.48–0.77].

Conclusion

Our study confirms that LV-LS is load-dependent; however, the variations in LV-LS after PLR is not a discriminating criterion to predict fluid responsiveness of ICU patients with ACF in this cohort.

Management of sepsis and septic shock in the emergency department

Early management of sepsis and septic shock is crucial for patients' prognosis. As the Emergency Department (ED) is the place where the first medical contact for septic patients is likely to occur, emergency physicians play an essential role in the early phases of patient management, which consists of accurate initial diagnosis, resuscitation, and early antibiotic treatment. Since the issuing of the Surviving Sepsis Campaign guidelines in 2016, several studies have been published on different aspects of sepsis management, adding a substantial amount of new information on the pathophysiology and treatment of sepsis and septic shock. In light of this emerging evidence, the present narrative review provides a comprehensive account of the recent advances in septic patient management in the ED.

Essential Emergency and Critical Care: a consensus among global clinical experts

BACKGROUND

Globally, critical illness results in millions of deaths every year. Although many of these deaths are potentially preventable, the basic, life-saving care of critically ill patients are often overlooked in health systems. Essential Emergency and Critical Care (EECC) has been devised as the care that should be provided to all critically ill patients in all hospitals in the world. EECC includes the effective care of low cost and low complexity for the identification and treatment of critically ill patients across all medical specialties. This study aimed to specify the content of EECC and additionally, given the surge of critical illness in the ongoing pandemic, the essential diagnosis-specific care for critically ill patients with COVID-19.

METHODS

In a Delphi process, consensus (>90% agreement) was sought from a diverse panel of global clinical experts. The panel iteratively rated proposed treatments and actions based on previous guidelines and the WHO/ICRC's Basic Emergency Care. The output from the Delphi was adapted iteratively with specialist reviewers into a coherent and feasible package of clinical processes plus a list of hospital readiness requirements.

RESULTS

The 269 experts in the Delphi panel had clinical experience in different acute medical specialties from 59 countries and from all resource settings. The agreed EECC package contains 40 clinical processes and 67 requirements, plus additions specific for COVID-19.

CONCLUSION

The study has specified the content of care that should be provided to all critically ill patients. Implementing EECC could be an effective strategy for policy makers to reduce preventable deaths worldwide.

Changes in pulse pressure variation to assess preload responsiveness in mechanically ventilated patients with spontaneous breathing activity: an observational study

BACKGROUND

Pulse pressure variation (PPV) is not reliable in predicting preload responsiveness in patients receiving mechanical with spontaneous breathing (SB) activity. We hypothesised that an increase in PPV after a tidal volume (V_T) challenge (TVC) or a decrease in PPV during passive leg raising (PLR) can predict preload responsiveness in such cases.

METHODS

This prospective observational study was performed in two ICUs and included patients receiving mechanical ventilation with SB, for whom the treating physician decided to test preload responsiveness. Transthoracic echocardiography was used to measure the velocity-time integral (VTI) of the left ventricular outflow tract. Patients exhibiting an increase in VTI ≥12% during PLR were defined as PLR+ patients (or preload responders). Then, a TVC was performed by increasing V_T by 2 ml kg^-1 predicted body weight (PBW) for 1 min. PPV was recorded at each step.

RESULTS

Fifty-four patients (Simplified Acute Physiology Score II: 60 (25) ventilated with a V_T of 6.5 (0.8) ml kg^-1 PBW, were included. Twenty-two patients were PLR+. The absolute decrease in PPV during PLR and the absolute increase in PPV during TVC discriminated between PLR+ and PLR- patients with area under the receiver operating characteristic (AUROC) curve of 0.78 and 0.73, respectively, and cut-off values of -1% and +2%, respectively. Those AUROC curve values were similar but were significantly different from that of baseline PPV (0.61).

CONCLUSION

In patients undergoing mechanical ventilation with SB activity, PPV does not predict preload responsiveness. However, the decrease in PPV during PLR and the increase in PPV during a TVC help discriminate preload responders from non-responders with moderate accuracy.

CLINICAL TRIAL REGISTRATION

NCT04369027 (ClinicalTrials.gov).

Evaluation of the quick sequential organ failure assessment score plus lactate in critically ill dogs

OBJECTIVES

To apply the quick sequential organ failure assessment (qSOFA) score to dogs admitted to a veterinary ICU, and evaluate whether the addition of lactate increased the predictive ability of the score.

MATERIALS AND METHODS

A quick sequential organ failure assessment score of 0, 1, 2, or 3 was assigned to each dog based on the following criteria: respiratory rate >22 breaths per minute, altered mentation, systolic blood pressure <100 mmHg. Lactate was added to quick sequential organ failure assessment in an LqSOFA model and assigned to each patient. Disease processes evaluated included sepsis, congestive heart failure, pneumonia and pancreatitis.

RESULTS

Two hundred and sixty-seven client-owned dogs met the inclusion criteria. There was no significant difference in quick sequential organ failure assessment score between survivors and non-survivors. The use of lactate >3, 4, and 5 mmol/L incorporated into the quick sequential organ failure assessment score (L3qSOFA, L4qSOFA, L5qSOFA) distinguished between survival and non-survival (AUC=0.62; AUC=0.64; AUC=0.62, respectively). Lactate alone distinguished between survival and non-survival (AUC=0.63). Lactate concentration was significantly lower in survivors.

CLINICAL SIGNIFICANCE

In this study, quick sequential organ failure assessment was not able to predict survival in a general population of critically ill patients. The addition of lactate to the quick sequential organ failure assessment score slightly increased the predictive ability of the score.

Assessment of Volume Status and Fluid Responsiveness in Small Animals

Intravenous fluids are an essential component of shock management in human and veterinary emergency and critical care to increase cardiac output and improve tissue perfusion. Unfortunately, there are very few evidence-based guidelines to help direct fluid therapy in the clinical setting. Giving insufficient fluids and/or administering fluids too slowly to hypotensive patients with hypovolemia can contribute to continued hypoperfusion and increased morbidity and mortality. Similarly, giving excessive fluids to a volume unresponsive patient can contribute to volume overload and can equally increase morbidity and mortality. Therefore, assessing a patient's volume status and fluid responsiveness, and monitoring patient's response to fluid administration is critical in maintaining the balance between meeting a patient's fluid needs vs. contributing to complications of volume overload. This article will focus on the physiology behind fluid responsiveness and the methodologies used to estimate volume status and fluid responsiveness in the clinical setting.

Effects of IV Fluids in Dogs and Cats With Kidney Failure

Intravenous fluid therapy has long been the mainstay of treatment of kidney disease, including acute kidney injury and uremic crisis associated with chronic kidney disease. Careful management of fluid dose is critical, as animals with kidney disease may have marked derangements in their ability to regulate fluid homeostasis and acid-base status. Understanding of the physiology of renal fluid handling is necessary, along with repeated attention to parameters of fluid status, electrolytes, and acid-base balance, to achieve optimal hydration status and avoid further damage or decrease in function from dehydration or overhydration.

The Surviving Sepsis Campaign: Fluid Resuscitation and Vasopressor Therapy Research Priorities in Adult Patients

OBJECTIVE

Expand upon the priorities of fluid resuscitation and vasopressor therapy research priorities identified by a group of experts assigned by the Society of Critical Care Medicine and the European Society of Intensive Care Medicine.

DATA SOURCES

Original article, literature search.

STUDY SELECTION

Several members of the original task force with expertise specific to the area of fluid resuscitation and vasopressor therapy.

DATA EXTRACTION

None.

DATA SYNTHESIS

None.

CONCLUSION

In the second of a series of manuscripts subsequent to the original article, members with expertise in the subjects expound upon the three identified priorities related to fluid resuscitation and vasopressor therapies. This analysis summarizes what is known and what were identified as ongoing and future research.

Volume status and volume responsiveness in postoperative cardiac surgical patients: An observational, multicentre cohort study

BACKGROUND

The best strategy to identify patients in whom fluid loading increases cardiac output (CO) following cardiac surgery remains debated. This study examined the utility of a calculated mean systemic filling pressure analogue (P_msa ) and derived variables to explain the response to a fluid bolus.

METHODS

The P_msa was calculated using retrospective, observational cohort data in the early postoperative period between admission to the intensive care unit and extubation within 6 hours. The venous return pressure gradient (VRdP) was calculated as P_msa  - central venous pressure. Concurrent changes induced by a fluid bolus in the ratio of the VRdP over P_msa , the volume efficiency (E_vol ), were studied to assess fluid responsiveness. Changes between P_msa and derived variables and CO were analysed by Wilcoxon rank-sum test, hierarchial clustering and multiple linear regression.

RESULTS

Data were analysed for 235 patients who received 489 fluid boluses. The P_msa increased with consecutive fluid boluses (median difference [range] 1.3 [0.5-2.4] mm Hg, P = .03) with a corresponding increase in VRdP (median difference 0.4 [0.2-0.6] mm Hg, P = .04). Hierarchical cluster analysis only identified E_vol and the change in CO within one cluster. The multiple linear regression between P_msa and its derived variables and the change in CO (overall r²  = .48, P < .001) demonstrated the best partial regression between the continuous change in CO and the concurrent E_vol (r = .55, P < .001).

CONCLUSION

The mean systemic filling P_msa enabled a comprehensive interpretation of fluid responsiveness with volume efficiency useful to explain the change in CO as a continuous phenomenon.

The surviving sepsis campaign: fluid resuscitation and vasopressor therapy research priorities in adult patients

OBJECTIVE

To expand upon the priorities of fluid resuscitation and vasopressor therapy research priorities identified by a group of experts assigned by the Society of Critical Care Medicine and the European Society of Intensive Care Medicine.

DATA SOURCES

Original paper and literature search.

STUDY SELECTION

Several members of the original task force with expertise specific to the area of fluid resuscitation and vasopressor therapy.

DATA EXTRACTION

None.

DATA SYNTHESIS

None.

CONCLUSION

In the second of a series of manuscripts subsequent to the original paper, members with expertise in the subjects expound upon the three identified priorities related to fluid resuscitation and vasopressor therapies. This analysis summarizes what is known and what were identified as ongoing and future research.

Individualized Hemodynamic Management in Sepsis

Hemodynamic optimization remains the cornerstone of resuscitation in the treatment of sepsis and septic shock. Delay or inadequate management will inevitably lead to hypoperfusion, tissue hypoxia or edema, and fluid overload, leading eventually to multiple organ failure, seriously affecting outcomes. According to a large international survey (FENICE study), physicians frequently use inadequate indices to guide fluid management in intensive care units. Goal-directed and "restrictive" infusion strategies have been recommended by guidelines over "liberal" approaches for several years. Unfortunately, these "fixed regimen" treatment protocols neglect the patient's individual needs, and what is shown to be beneficial for a given population may not be so for the individual patient. However, applying multimodal, contextualized, and personalized management could potentially overcome this problem. The aim of this review was to give an insight into the pathophysiological rationale and clinical application of this relatively new approach in the hemodynamic management of septic patients.

Controversies in acute kidney injury: conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Conference

In 2012, Kidney Disease: Improving Global Outcomes (KDIGO) published a guideline on the classification and management of acute kidney injury (AKI). The guideline was derived from evidence available through February 2011. Since then, new evidence has emerged that has important implications for clinical practice in diagnosing and managing AKI. In April of 2019, KDIGO held a controversies conference entitled Acute Kidney Injury with the following goals: determine best practices and areas of uncertainty in treating AKI; review key relevant literature published since the 2012 KDIGO AKI guideline; address ongoing controversial issues; identify new topics or issues to be revisited for the next iteration of the KDIGO AKI guideline; and outline research needed to improve AKI management. Here, we present the findings of this conference and describe key areas that future guidelines may address.

Increase in Central Venous Pressure During Passive Leg Raising Cannot Detect Preload Unresponsiveness

OBJECTIVE

By analogy with the classical central venous pressure rules to assess a fluid challenge, we hypothesized that an increase in central venous pressure greater than or equal to 5 cm H2O (i.e., 4 mm Hg) during passive leg raising can predict preload unresponsiveness diagnosed by the absence of increase in velocity-time integral of the left ventricular outflow tract greater than or equal to 10% during the test (negative passive leg raising test).

DESIGN AND SETTINGS

Velocity-time integral was measured by transthoracic echocardiography. Central venous pressure and velocity-time integral were measured before and during passive leg raising.

PATIENTS

Critically ill patients for whom the physician decided to test preload responsiveness by passive leg raising were prospectively included.

MEASUREMENT AND MAIN RESULTS

Fifty-seven set of measurements were performed in 50 patients. Preload unresponsiveness (negative passive leg raising test) was observed in 32 cases. The changes in central venous pressure during passive leg raising did not differ between positive passive leg raising cases (positive passive leg raising test) and negative passive leg raising test cases (3 ± 2 vs 3 ± 2 mm Hg, respectively) and thus did not predict preload unresponsiveness (area under the receiver-operating characteristic curve of 0.59). An increase in central venous pressure greater than or equal to 4 mm Hg during passive leg raising was observed in 10 cases of positive passive leg raising test and in 11 cases of negative passive leg raising test. Taking an increase in central venous pressure greater than or equal to 3 or greater than or equal to 5 mm Hg rather than greater than or equal to 4 mm Hg during passive leg raising did not better allow one to identify negative passive leg raising test.

CONCLUSIONS

Marked increase in central venous pressure during passive leg raising cannot identify negative passive leg raising test cases and thus preload unresponsiveness. Measurements of cardiac output (or its surrogates) during passive leg raising are, thus, mandatory to appropriately interpret this test.