Nutrition dose in the early acute phase of critical illness: Finding the sweet spot and heeding the lessons from the NUTRIREA trials

The landmark NUTRIREA-2 and NUTRIREA-3 trials compared the route and dose of nutrition, respectively, in critically ill patients with circulatory shock. The results of both trials support a "less-is-more" paradigm shift in the early acute phase of critical illness. In this review, the authors outline and appraise the results of the NUTRIREA-2 and NUTRIREA-3 trials, introduce the concept of identifying the "sweet spot" for nutrition dose based on severity of illness/nutrition risk and nutrition dose, and identify the unintended consequences of delivering full-dose nutrition in sicker critically ill patients during the early acute phase of critical illness.

Monitoring Macro- and Microcirculation in the Critically Ill: A Narrative Review

Circulatory shock is a common and important diagnosis in the critical care environment. Hemodynamic monitoring is quintessential in the management of shock. The currently used hemodynamic monitoring devices not only measure cardiac output but also provide data related to the prediction of fluid responsiveness, extravascular lung water, and also pulmonary vascular permeability. Additionally, these devices are minimally invasive and associated with fewer complications. The area of hemodynamic monitoring is progressively evolving with a trend toward the use of minimally invasive devices in this area. The critical care physician should be well-versed with current hemodynamic monitoring limitations and stay updated with the upcoming advances in this field so that optimal therapy can be delivered to patients in circulatory shock.

Association of Brain Injury Biomarkers and Circulatory Shock Following Moderate-Severe Traumatic Brain Injury: A TRACK-TBI Study

INTRODUCTION

Early circulatory shock following traumatic brain injury (TBI) is a multifactorial process; however, the impact of brain injury biomarkers on the risk of shock has not been evaluated. We examined the association between neuronal injury biomarker levels and the development of circulatory shock following moderate-severe TBI.

METHODS

In this retrospective cohort study, we examined adults with moderate-severe TBI (Glasgow Coma Scale score <13) enrolled in the TRACK-TBI study, an 18-center prospective TBI cohort study. The exposures were day-1 levels of neuronal injury biomarkers (glial fibrillary acidic protein, ubiquitin C-terminal hydrolase-L1 [UCH-L1], S100 calcium-binding protein B [S100B], neuron-specific enolase), and of an inflammatory biomarker (high-sensitivity C-reactive protein). The primary outcome was the development of circulatory shock, defined as cardiovascular Sequential Organ Failure Assessment Score ≥2 within 72 hours of admission. Association between day-1 biomarker levels and the development of circulatory shock was assessed with regression analysis.

RESULTS

The study included 392 subjects, with a mean age of 40 years; 314 (80%) were male and 165 (42%) developed circulatory shock. Median (interquartile range) day-1 levels of UCH-L1 (994.8 [518.7 to 1988.2] pg/mL vs. 548.1 [280.2 to 1151.9] pg/mL; P <0.0001) and S100B (0.47 μg/mL [0.25 to 0.88] vs. 0.27 [0.16 to 0.46] μg/mL; P <0.0001) were elevated in those who developed early circulatory shock compared with those who did not. In multivariable regression, there were associations between levels of both UCH-L1 (odds ratio, 1.63 [95% confidence interval, 1.25-2.12]; P <0.0005) and S100B (odds ratio, 1.73 [95% confidence interval 1.27-2.36]; P <0.0005) with the development of circulatory shock.

CONCLUSION

Neuronal injury biomarkers may provide the improved mechanistic understanding and possibly early identification of patients at risk for early circulatory shock following moderate-severe TBI.

Infrared Thermography Imaging for Assessment of Peripheral Perfusion in Patients with Septic Shock

Skin temperature changes can be used to assess peripheral perfusion in circulatory shock patients. However, research has been limited to point measurements from acral parts of the body. Infrared thermography allows non-invasive evaluation of temperature distribution over a larger surface. Our study aimed to map thermographic patterns in the knee and upper thigh of 81 septic shock patients within 24 h of admission and determine the relationship between skin temperature patterns, mottling, and 28-day mortality. We extracted skin temperature measurements from zones corresponding to mottling scores and used a linear mixed model to analyze the distribution of skin temperature in patients with different mottling scores. Our results showed that the distribution of skin temperature in the anterior thigh and knee is physiologically heterogeneous and has no significant association with mottling or survival at 28 days. However, overall skin temperature of the anterior thigh and knee is significantly lower in non-survivors when modified by mottling score. No differences were found in skin temperature between the survivor and non-survivor groups. Our study shows the potential usefulness of infrared thermography in evaluating skin temperature patterns in resuscitated septic shock patients. Overall skin temperature of the anterior thigh and knee may be an important indicator of survival status when modified by mottling score.

Levosimendan in the Treatment of Patients with Severe Septic Cardiomyopathy

(1) Background: The optimal treatment of septic cardiomyopathy (SCM) remains questionable. The aim of the study was to compare the treatment of SCM based on levosimendan versus the best available therapy. (2) Methods: We conducted an observational study including patients with severe septic cardiomyopathy and circulatory failure. (3) Results: Fourteen patients (61%) received levosimendan, and nine received other treatments. The patients in the levosimendan group were more severely ill [APACHE II: 23.5 (14, 37) vs. 14 (13, 28), respectively, p = 0.012], and there was a trend for more decompensated LV function depicted by the LVEF [15% (10, 20) vs. 25% (5, 30), respectively, p = 0.061]. However, they presented a significantly higher increase in LVEF after seven days [15% (10, 20) to 50% (30, 68) (p < 0.0001) vs. 25% (5, 30) to 25% (15, 50) (p = 0.309), and a significantly higher decrease in lactate levels during the first 24 h [4.5 (2.5, 14.4) to 2.85 (1.2, 15), p = 0.036 vs. 2.9 (2, 18.9) to 2.8 (1, 15), p = 0.536]. Seven-day survival (64.3% vs. 33.3%, p = 0.424) and ICU survival (50% vs. 22.2%, p = 0.172) were higher in the first group, although differences did not reach statistical significance. The degree of left ventricular impairment and the magnitude of EF improvement by the seventh-day post-SCM onset were associated with mortality in regression analysis. (4) Conclusions: Our study presents main hemodynamic data supporting the possible efficacy of levosimendan treatment in patients with severe SCM.

Resuscitative TEE after open heart surgery: When POCUS fails to FOCUS

Echocardiography is key in evaluating the cause of collapse in the post-cardiac surgery patient. Transesophageal echocardiography provides a greater capability for the diagnosis of pericardial effusion in patients who arrest after cardiac surgery.

Right Lower Extremity Phlegmasia Cerulea Dolens Due to Iliotibial Vein Thrombosis With Compartment Syndrome and Circulatory Shock: Case Report and Review

Phlegmasia cerulea dolens (PCD) is a rare and life-threatening complication of extensive deep vein thrombosis (DVT) characterized by severe pain, swelling, and cyanosis of the affected limb. It results from total or near-total occlusion of the deep and superficial veins of a limb, leading to venous congestion and ischemia. It is associated with 40% mortality, more commonly affecting the left lower extremity, with up to 50% of patients requiring limb amputations. PCD complicated by compartment syndrome (CS) with shock and multiorgan failure is very rare. We report the case of a 55-year-old female who presented with sudden onset, severe right lower extremity pain and swelling with associated limb discoloration, paresthesias, and inability to move the toes of her right foot. On examination, there was cyanosis, pulselessness, and tense right leg and thigh compartments. Doppler ultrasonography revealed DVT of the right external iliac extending to the posterior tibial vein. A diagnosis of PCD with CS was made and the patient was immediately started on anticoagulation with unfractionated heparin and emergent decompressive fasciotomies of the right leg and thigh were performed. Following the fasciotomies, she developed circulatory shock and went into cardiac arrest. Despite successful resuscitation, her hemodynamic instability and multiorgan failure precluded further life-saving interventions including thrombolysis or thrombectomy. Limb amputation was declined given her poor prognosis and she passed away shortly thereafter. This case illustrates the rare occurrence of right lower extremity PCD complicated by CS, circulatory shock, and multiorgan failure, which can sometimes occur despite emergency fasciotomy but can be averted with prompt intervention. These complications often preclude immediate thrombolysis and/or thrombectomy. Its recognition, therefore, warrants timely and more aggressive interventions to prevent limb loss or death.

Beta-blocker treatment in the critically ill: a systematic review and meta-analysis

BACKGROUND

Critical illness may lead to activation of the sympathetic system. The sympathetic stimulation may be further increased by exogenous catecholamines, such as vasopressors and inotropes. Excessive adrenergic stress has been associated with organ dysfunction and higher mortality. β-Blockers may reduce the adrenergic burden, but they may also compromise perfusion to vital organs thus worsening organ dysfunction. To assess the effect of treatment with β-blockers in critically ill adults, we conducted a systematic review and meta-analysis of randomized controlled trials.

MATERIALS AND METHODS

We conducted a search from three major databases: Ovid Medline, the Cochrane Central Register for Controlled Trials and Scopus database. Two independent reviewers screened, selected, and assessed the included articles according to prespecified eligibility criteria. We assessed risk of bias of eligible articles according to the Cochrane guidelines. Quality of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

RESULTS

Sixteen randomized controlled trials comprising 2410 critically ill patients were included in the final review. A meta-analysis of 11 trials including 2103 patients showed a significant reduction in mortality in patients treated with β-blockers compared to control (risk ratio 0.65, 95%CI 0.53-0.79; p < .0001). There was no significant difference in mean arterial pressure or vasopressor load. Quality of life, biventricular ejection fraction, blood lactate levels, cardiac biomarkers and mitochondrial function could not be included in meta-analysis due to heterogenous reporting of outcomes.

CONCLUSIONS

In this systematic review we found that β-blocker treatment reduced mortality in critical illness. Use of β-blockers in critical illness thus appears safe after initial hemodynamic stabilization. High-quality RCT's are needed to answer the questions concerning optimal target group of patients, timing of β-blocker treatment, choice of β-blocker, and choice of physiological and hemodynamic parameters to target during β-blocker treatment in critical illness.KEY MESSAGESA potential outcome benefit of β-blocker treatment in critical illness exists according to the current review and meta-analysis. Administration of β-blockers to resuscitated patients in the ICU seems safe in terms of hemodynamic stability and outcome, even during concomitant vasopressor administration. However, further studies, preferably large RCTs on β-blocker treatment in the critically ill are needed to answer the questions concerning timing and choice of β-blocker, patient selection, and optimal hemodynamic targets.

Risk Factors and Neurological Outcomes Associated With Circulatory Shock After Moderate-Severe Traumatic Brain Injury: A TRACK-TBI Study

BACKGROUND

Extracranial multisystem organ failure is a common sequela of severe traumatic brain injury (TBI). Risk factors for developing circulatory shock and long-term functional outcomes of this patient subset are poorly understood.

OBJECTIVE

To identify emergency department predictors of circulatory shock after moderate-severe TBI and examine long-term functional outcomes in patients with moderate-severe TBI who developed circulatory shock.

METHODS

We conducted a retrospective cohort study using the Transforming Clinical Research and Knowledge in TBI database for adult patients with moderate-severe TBI, defined as a Glasgow Coma Scale (GCS) score of <13 and stratified by the development of circulatory shock within 72 hours of hospital admission (Sequential Organ Failure Assessment score ≥2). Demographic and clinical data were assessed with descriptive statistics. A forward selection regression model examined risk factors for the development of circulatory shock. Functional outcomes were examined using multivariable regression models.

RESULTS

Of our moderate-severe TBI population (n = 407), 168 (41.2%) developed circulatory shock. Our predictive model suggested that race, computed tomography Rotterdam scores <3, GCS in the emergency department, and development of hypotension in the emergency department were associated with developing circulatory shock. Those who developed shock had less favorable 6-month functional outcomes measured by the 6-month GCS-Extended (odds ratio 0.36, P = .002) and 6-month Disability Rating Scale score (Diff. in means 3.86, P = .002) and a longer length of hospital stay (Diff. in means 11.0 days, P < .001).

CONCLUSION

We report potential risk factors for circulatory shock after moderate-severe TBI. Our study suggests that developing circulatory shock after moderate-severe TBI is associated with poor long-term functional outcomes.

Lessons of the month 1: Shoshin beriberi: A case report of fulminant cardiovascular collapse, intractable hyperlactatemia and deteriorating consciousness

Shoshin beriberi is a fulminant variant of thiamine deficiency, often presenting with severe lactic acidosis and cardiogenic shock. Due to the sparsity of this condition, delays in diagnosis can lead to fatality. However, rapid reversal of symptoms can be easily achieved through intravenous thiamine replacement.In this case report, we discuss a 57-year-old woman, who was previously fit and well, who presented to the emergency department with a 3-day history of extreme malaise, breathlessness and abdominal pain, with marked hypotension and tachycardia requiring vasopressor support and a severe rising lactic acidosis. Upon further questioning, a history of alcohol excess was noted. Rapid reversal of the marked haemodynamic instability was achieved upon administration of intravenous thiamine and the patient was discharged within 48 hours.

Three-dimensional critical care transesophageal echocardiography: A bedside tool in the diagnosis and management of shock

Critical care echocardiography has become fundamental in diagnosis, management, and monitoring of patients in shock. Transesophageal echocardiography has gained importance, particularly in critically ill patients under mechanical ventilation. We describe echocardiographic findings concerning a patient admitted with confusion, pulmonary edema, hypotension, and systolic murmur at apex.

Low Microcirculatory Perfused Vessel Density and High Heterogeneity are Associated With Increased Intensity and Duration of Lactic Acidosis After Cardiac Surgery with Cardiopulmonary Bypass

INTRODUCTION

Lactic acidosis after cardiac surgery with cardiopulmonary bypass is common and associated with an increase in postoperative morbidity and mortality. A number of potential causes for an elevated lactate after cardiopulmonary bypass include cellular hypoxia, impaired tissue perfusion, ischemic-reperfusion injury, aerobic glycolysis, catecholamine infusions, and systemic inflammatory response after exposure to the artificial cardiopulmonary bypass circuit. Our goal was to examine the relationship between early abnormalities in microcirculatory convective blood flow and diffusive capacity and lactate kinetics during early resuscitation in the intensive care unit. We hypothesized that patients with impaired microcirculation after cardiac surgery would have a more severe postoperative hyperlactatemia, represented by the lactate time-integral of an arterial blood lactate concentration greater than 2.0 mmol/L.

METHODS

We measured sublingual microcirculation using incident darkfield video microscopy in 50 subjects on intensive care unit admission after cardiac surgery. Serial measurements of systemic hemodynamics, blood gas, lactate, and catecholamine infusions were recorded each hour for the first 6 h after surgery. Lactate area under the curve (AUC) was calculated over the first 6 h. The lactate AUC was compared between subjects with normal and low perfused vessel density (PVD < 18 mm/mm2), high microcirculatory heterogeneity index (MHI > 0.4), and low vessel-by-vessel microvascular flow index (MFIv < 2.6).

RESULTS

Thirteen (26%) patients had a low postoperative PVD, 20 patients (40%) had a high MHI, and 26 (52%) patients had a low MFIv. Patients with low perfused vessel density had higher lactate AUC compared with subjects with a normal PVD (22.3 [9.4-31.0] vs. 2.6 [0-8.8]; P < 0.0001). Patients with high microcirculatory heterogeneity had a higher lactate AUC compared with those with a normal MHI (2.5 [0.1-8.2] vs. 13.1 [3.7-31.1]; P < 0.001). We did not find a difference in lactate AUC when comparing high and low MFIv.

CONCLUSION

Low perfused vessel density and high microcirculatory heterogeneity are associated with an increased intensity and duration of lactic acidosis after cardiac surgery with cardiopulmonary bypass.

Impact of integrated graphical display on expert and novice diagnostic performance in critical care

OBJECTIVE

To determine the impact of a graphical information display on diagnosing circulatory shock.

MATERIALS AND METHODS

This was an experimental study comparing integrated and conventional information displays. Participants were intensivists or critical care fellows (experts) and first-year medical residents (novices).

RESULTS

The integrated display was associated with higher performance (87% vs 82%; P < .001), less time (2.9 vs 3.5 min; P = .008), and more accurate etiology (67% vs 54%; P = .048) compared to the conventional display. When stratified by experience, novice physicians using the integrated display had higher performance (86% vs 69%; P < .001), less time (2.9 vs 3.7 min; P = .03), and more accurate etiology (65% vs 42%; P = .02); expert physicians using the integrated display had nonsignificantly improved performance (87% vs 82%; P = .09), time (2.9 vs 3.3; P = .28), and etiology (69% vs 67%; P = .81).

DISCUSSION

The integrated display appeared to support efficient information processing, which resulted in more rapid and accurate circulatory shock diagnosis. Evidence more strongly supported a difference for novices, suggesting that graphical displays may help reduce expert-novice performance gaps.

Circulatory Shock among Hospitalized Patients for Salicylate Intoxication

BACKGROUND

This study aimed to evaluate the risk factors for circulatory shock and its impact on outcomes in patients hospitalized for salicylate intoxication.

METHODS

We used the National Inpatient Sample to identify patients hospitalized primarily for salicylate intoxication from 2003-2014. Circulatory shock was identified based on hospital diagnosis code for any type of shock or hypotension. We compared clinical characteristics, in-hospital treatments, outcomes, and resource use between patients with and without circulatory shock associated with salicylate intoxication.

RESULTS

Of 13,805 hospital admissions for salicylate intoxication, circulatory shock developed in 484 (4%) admissions. Risk factors for development of circulatory shock included older age, female sex, concurrent psychotropic medication overdose, anemia, congestive heart failure, volume depletion, rhabdomyolysis, seizure, gastrointestinal bleeding, and sepsis. Circulatory shock was significantly associated with increased odds of any organ failure and in-hospital mortality. Length of hospital stay and hospitalization cost was significantly higher in patients with circulatory shock.

CONCLUSION

Approximately 4% of patients admitted for salicylate intoxication developed circulatory shock. Circulatory shock was associated with worse clinical outcomes and increased resource use.

Microcirculation vs. Mitochondria-What to Target?

Circulatory shock is associated with marked disturbances of the macro- and microcirculation and flow heterogeneities. Furthermore, a lack of tissue adenosine trisphosphate (ATP) and mitochondrial dysfunction are directly associated with organ failure and poor patient outcome. While it remains unclear if microcirculation-targeted resuscitation strategies can even abolish shock-induced flow heterogeneity, mitochondrial dysfunction and subsequently diminished ATP production could still lead to organ dysfunction and failure even if microcirculatory function is restored or maintained. Preserved mitochondrial function is clearly associated with better patient outcome. This review elucidates the role of the microcirculation and mitochondria during circulatory shock and patient management and will give a viewpoint on the advantages and disadvantages of tailoring resuscitation to microvascular or mitochondrial targets.

Near-Infrared Spectroscopy in Adult Circulatory Shock: A Systematic Review

BACKGROUND

Circulatory shock affects every third patient in intensive care units and is associated with high mortality. Near-infrared spectroscopy (NIRS) could serve as a means for monitoring tissue perfusion in circulatory shock.

PURPOSE

To assess the evidence of NIRS monitoring in circulatory shock, we conducted a systematic review of the literature.

METHODS

The study protocol was registered in International Prospective Register of Systematic Reviews (PROSPERO). We searched PubMed, Ovid MEDLINE, Scopus, and EBM Reviews databases. The reference lists of included articles, last volumes of key journals, and NIRS monitor manufacturers' webpages were searched manually. Two reviewers independently selected included studies. The quality of studies was assessed. The qualitative synthesis was guided by 3 questions: First, does NIRS monitoring improve patient-centered outcomes in adult circulatory shock patient? Second, do NIRS-derived parameters predict patient-centered outcomes, such as mortality and organ dysfunction, and third, does NIRS monitoring give additional information to guide treatment decisions?

MAIN RESULTS

Eighteen observational studies with 927 patients were included. Because of considerable clinical heterogeneity of the data, we were not able to perform a meta-analysis. Also, due to lack of randomized controlled trials, the first review question could not be answered. Based on the current review, baseline tissue oxygen saturation (StO2) however seems to predict mortality and identify patients with most severe forms of circulatory shock.

CONCLUSIONS

Near-infrared spectroscopy-derived StO2 can predict mortality in circulatory shock, but high-quality data on the impact of NIRS monitoring are lacking. Furthermore, the marked heterogeneity of the studies makes combining the results of individual studies difficult. Standardization of methodology and clinical randomized trials are needed before wider clinical use.

Safety and Outcomes of Early Enteral Nutrition in Circulatory Shock

Circulatory shock is one of the most common reasons for an intensive care unit admission, has been shown to impair gut barrier and immune functions, and promotes dysbiosis. The exact timing and dose of enteral nutrition (EN) in circulatory shock remains unclear. In fact, because of fear of complications such as nonocclusive mesenteric ischemia and bowel necrosis and splanchnic steal phenomenon, clinicians may hesitate to start EN in critically ill patients with circulatory shock. In this narrative review, we identify and appraise contemporary evidence evaluating the safety and outcomes of EN in circulatory shock.

Why Methylene Blue Have to Be Always Present in the Stocking of Emergency Antidotes

Evidence-based review of the existing literature ultimately recommends stocking of Methylene Blue (MB) as an emergency antidote in the United States. The same is reported around the world in Japan, Greece, Italy and Canada. The observation that MB is always present as the main antidote required in emergency and critical care units calls for a revisit on its effects on the NO/cGMP system to reemphasize its multisystem actions. Therefore, the present review aimed to display the role of MB in emergency units, concerning: 1) Polytrauma and circulatory shock; 2) Neuroprotection, 3) Anaphylaxis and, 4) Overdose and poisoning.

Central Venous Pressure (CVP) Reduction Associated With Higher Cardiac Output (CO) Favors Good Prognosis of Circulatory Shock: A Single-Center, Retrospective Cohort Study

Background: The Frank-Starling curve is the basis of hemodynamics. Changes in cardiac output (CO) caused by central venous pressure (CVP) are the most important concerns in the treatment of critically ill patients.

Objectives: To explore the use of CVP and its relevant mechanisms with respect to CO in the clinic.

Methods: A total of 134 patients with circulatory shock were retrospectively included and analyzed. Hemodynamic data were recorded and analyzed at PICCO initiation and 24 h after PICCO. Data regarding 28-day mortality and renal function were also collected.

Results: The patients were divided into a CVP↑+ CO↑ group (n = 23), a CVP↑+ CO↓ group (n = 29), a CVP↓+ CO↑ group (n = 44), and a CVP↓+ CO↓ group (n = 38) based on values at PICCO initiation and 24 h after PICCO. Post- hoc tests showed that the CVP↓+ CO↑ group had a higher 28-day survival than the other groups [log-rank (Mantel-Cox) = 8.758, 95%, CI, 20.112–23.499, P = 0.033]. In terms of hemodynamic characteristics, the CVP↓+ CO↑ group had a lower cardiac function index (CFI) (4.1 ± 1.4/min) and higher extravascular lung water index (EVLWI) (11.0 ± 4.7 ml/kg) at PICCO initiation. This group used more cardiotonic drugs (77.3%, P < 0.001) and had a negative fluid balance (−780.4 ± 1720.6 ml/24 h, P = 0.018) 24 h after PICCO than the other three groups. Cardiotonic drug use and dehydration treatment were associated with increased CFI (from 4.1 ± 1.4 /min to 4.5 ± 1.3/min, P = 0.07) and reduced ELVWI (from 11.0 ± 4.7 ml/kg to 9.0 ± 3.5 ml/kg, P = 0.029). Renal function tests showed that SCr and BUN levels in the CVP↓+ CO↑ group were significantly improved (SCr from 197.1 ± 128.9 mmol/L to 154.4 ± 90.8 mmol/L; BUN from 14.3 μmol/L ± 7.3 to 11.6 ± 7.0 μmol/L, P < 0.05).

Conclusions: Lower CVP was associated with increased CO, which may improve the 28-day prognosis in patients with circulatory shock. Notably, higher CO derived from lower CVP may also contribute to renal function improvement.

Calcium salt administration for circulatory shock due to severe hyperkalemia

Patients with severe hyperkalemia may present hemodynamic instability. The use of intravenous (IV) calcium for the treatment of hyperkalemia is based on sparse evidence. We hypothesized that the administration of calcium salts would decrease mortality in patients with severe hyperkalemia and circulatory shock. We report a case of a 56-year-old female who presented to an academic emergency department with acute confusion, lethargic mental status, and circulatory shock. Venous blood gas showed a potassium concentration of 7.9 mmol/L. The patient was given 2 g of IV calcium gluconate. The patient started to regain consciousness, and her blood pressure began to normalize. This emergency management led to an almost immediate resolution of the circulatory shock without the need for cardiac pacing. We conclude that hyperkalemia should be suspected in any patient presenting with acute onset of hypotension and bradycardia. IV calcium salts should be used for hemodynamic instability due to hyperkalemia.

Isolated Right Ventricular Stress (Takotsubo) Cardiomyopathy

A 79-year-old woman was admitted with a left femoral neck fracture and she immediately developed circulatory shock. Echocardiography showed a markedly enlarged right ventricle (RV) with systolic ballooning of the mid-ventricular wall and preserved contractility of the apex. The left ventricular (LV) motion was normal. Multi-detector-row computed tomography showed severe congestion of the contrast media in the right atrium with no forward flow to RV, but no pulmonary embolism. She was successfully treated with percutaneous veno-arterial extracorporeal membrane oxygenation. This case presented with acute, profound, but reversible RV dysfunction triggered by acute stress in a manner similar to that seen in LV stress cardiomyopathy.

Role of Urinary Neutrophil Gelatinase-associated Lipocalin as a Biomarker of Acute Kidney Injury in Patients with Circulatory Shock

Background

The early prediction of acute kidney injury (AKI) by the current clinical and laboratory methods remains inadequate. Neutrophil gelatinase-associated lipocalin (NGAL) has emerged as a promising noninvasive biomarker of kidney injury in shock. The aim of this study was to assess the ability of urinary NGAL (uNGAL) to predict AKI in adult Intensive Care Unit (ICU) patients.

Materials and Methods

We prospectively studied 70 patients with circulatory shock admitted to the ICU over a period of 1 year. uNGAL was analyzed at ICU admission and after 24 h. Risk, injury, failure, loss, and end-stage kidney criteria were calculated at admission and for consecutive 4 days. The primary outcome was AKI defined as an increase in creatinine of at least 50% from baseline or a reduction in urine output to <0.5 ml/kg/h for 6 h.

Results

uNGAL was a good diagnostic marker for AKI development; at day 1, the cutoff value 48.54 ng/mL had a sensitivity and specificity of 79.49 and 73.14, respectively, and the area under the curve (AUC) of 0.82 (95% confidence interval [CI], 0.75-0.87) for predicting AKI. At day 2, the cutoff value 190.92 ng/mL had a sensitivity and specificity of 90.0 and 64.66, respectively, and the AUC of 0.76 (95% CI, 0.70-0.88) for predicting AKI.

Conclusion

uNGAL could be a good early predictor biomarker of AKI following circulatory shock.

The Diagnosis and Hemodynamic Monitoring of Circulatory Shock: Current and Future Trends

Circulatory shock is a complex clinical syndrome encompassing a group of conditions that can arise from different etiologies and presented by several different hemodynamic patterns. If not corrected, cell dysfunction, irreversible multiple organ insufficiency, and death may occur. The four basic types of shock, hypovolemic, cardiogenic, obstructive and distributive, have features similar to that of hemodynamic shock. It is therefore essential, when monitoring hemodynamic shock, to making accurate clinical assessments which will guide and dictate appropriate management therapy. The European Society of Intensive Care has recently made recommendations for monitoring hemodynamic shock. The present paper discusses the issues raised in the new statements, including individualization of blood pressure targets, prediction of fluid responsiveness, and the use of echocardiography as the first means during the initial evaluation of circulatory shock. Also, the place of more invasive hemodynamic monitoring techniques and future trends in hemodynamic and metabolic monitoring in circulatory shock, will be debated.

Task force of the European Society of Intensive Care Medicine

OBJECTIVE

Circulatory shock is a life-threatening syndrome resulting in multiorgan failure and a high mortality rate. The aim of this consensus is to provide support to the bedside clinician regarding the diagnosis, management and monitoring of shock.

METHODS

The European Society of Intensive Care Medicine invited 12 experts to form a Task Force to update a previous consensus (Antonelli et al.: Intensive Care Med 33:575-590, 2007). The same five questions addressed in the earlier consensus were used as the outline for the literature search and review, with the aim of the Task Force to produce statements based on the available literature and evidence. These questions were: (1) What are the epidemiologic and pathophysiologic features of shock in the intensive care unit? (2) Should we monitor preload and fluid responsiveness in shock? (3) How and when should we monitor stroke volume or cardiac output in shock? (4) What markers of the regional and microcirculation can be monitored, and how can cellular function be assessed in shock? (5) What is the evidence for using hemodynamic monitoring to direct therapy in shock? Four types of statements were used: definition, recommendation, best practice and statement of fact.

RESULTS

Forty-four statements were made. The main new statements include: (1) statements on individualizing blood pressure targets; (2) statements on the assessment and prediction of fluid responsiveness; (3) statements on the use of echocardiography and hemodynamic monitoring.

CONCLUSIONS

This consensus provides 44 statements that can be used at the bedside to diagnose, treat and monitor patients with shock.

Overexpression of GTP cyclohydrolase 1 feedback regulatory protein is protective in a murine model of septic shock

Overproduction of nitric oxide (NO) by inducible NO synthase contributes toward refractory hypotension, impaired microvascular perfusion, and end-organ damage in septic shock patients. Tetrahydrobiopterin (BH4) is an essential NOS cofactor. GTP cyclohydrolase 1 (GCH1) is the rate-limiting enzyme for BH4 biosynthesis. Under inflammatory conditions, GCH1 activity and hence BH4 levels are increased, supporting pathological NOS activity. GCH1 activity can be controlled through allosteric interactions with GCH1 feedback regulatory protein (GFRP). We investigated whether overexpression of GFRP can regulate BH4 and NO production and attenuate cardiovascular dysfunction in sepsis. Sepsis was induced in mice conditionally overexpressing GFRP and wild-type littermates by cecal ligation and puncture. Blood pressure was monitored by radiotelemetry, and mesenteric blood flow was quantified by laser speckle contrast imaging. Blood biochemistry data were obtained using an iSTAT analyzer, and BH4 levels were measured in plasma and tissues by high-performance liquid chromatography. Increased BH4 and NO production and hypotension were observed in all mice, but the extents of these pathophysiological changes were attenuated in GFRP OE mice. Perturbations in blood biochemistry were similarly attenuated in GFRP OE compared with wild-type controls. These results suggest that GFRP overexpression regulates GCH1 activity during septic shock, which in turn limits BH4 bioavailability for iNOS. We conclude that the GCH1-GFRP axis is a critical regulator of BH4 and NO production and the cardiovascular derangements that occur in septic shock.

Episodic idiopathic systemic capillary leak syndrome in a girl

Episodic idiopathic systemic capillary leak syndrome is a rare disorder that presents with attacks of circulatory shock due to plasma leakage into the extravascular space. Reported here is the case of a girl who had recurrent circulatory shock. The diagnosis of episodic idiopathic systemic capillary leak syndrome was made following the fourth episode. The course was favorable following acute i.v. cristalloids and methylprednisolone.

Rat hepatic and splanchnic vascular responses to anaphylactic shock, compared with hemorrhagic or vasodilator-induced shock

BACKGROUND

Hemodynamics during anaphylactic shock remain unclear. We determined hepatic and splanchnic responses to anaphylactic hypotension, compared with hemorrhage or sodium nitroprusside (SNP)-induced hypotension, in anesthetized rats.

MATERIALS AND METHODS

Portal pressure, systemic arterial pressure (SAP), central venous pressure, portal and hepatic arterial blood flow were measured. Splanchnic (Rspl), portal venous (Rpv), and hepatic arterial (Rha) resistances were determined.

RESULTS

In rats with anaphylaxis induced by an intravenous injection of the ovalbumin antigen (n=6), hemorrhage (n=6), and SNP (2 mg/kg, n=6), SAP decreased similarly. During anaphylaxis, Rha and Rspl decreased only at 30 s after the antigen injection. Notably, Rpv increased markedly. During hemorrhage, Rspl and Rha increased and decreased, respectively, with Rpv not changing. After SNP, Rha and Rspl decreased with Rpv not changing.

CONCLUSION

Hepatic and splanchnic vascular responses differ according to the type of shock. Anaphylactic hypotension is characterized by markedly increased portal venous resistance. Splanchnic and hepatic artery dilatation occurs only at the beginning of hypotension in anesthetized rats.

HDFx: a novel biologic immunomodulator is therapeutically -effective in hemorrhagic and intestinal-ischemic shock: importance of microcirculatory-immunological interactions and their potential implications for the warfighter and disaster victims

Recently, we have reported on the discovery of a new, conserved protein (35-40 kD), termed HDFx, that protects rats, guinea-pigs, mice and rabbits against lethal hemorrhage, endotoxins, and traumatic injury when given, systemically, as a pretreatment. HDFx was also found to stimulate several arms of the immune system. The present report demonstrates, for the first time, that HDFx ,when administered post-hemorrhage and post-intestinal ischemia shock -trauma, yields increased survival rates, elevates falling arterial blood pressures, possesses unique actions in the microvasculature, stimulates depressed RES phagocytosis (normally observed in animals and humans during blood loss, sepsis and trauma), and preserves cytokine levels in lymphocytes obtained from animals subjected to hemorrhage and traumatic shock. We believe that HDFx presents a potential brand new therapeutic approach:1)for the injured warfighter on the battlefield, 2)for victims of major disasters, 3)as an adjunct for patients undergoing high -risk surgical procedures commonly found in open-heart surgery, cancers, and in neurosurgeries. Use of HDFx could potentially allow oncologists to decrease chemotherapy dosing, while increasing patient survival chances.

Why measure cardiac output?

Although cardiac output is a primary determinant of global O₂ transport there are no absolute values that reflect circulatory adequacy, though very low values are of negative prognostic use. There is no agreement as to what constitutes a clinically relevant change in cardiac output. A recent clinical trial suggests that early goal-directed therapy aimed at increasing cardiac output improves survival. Thus, in some patients, measurement of cardiac output is indicated as an aid to prognosis, diagnosis and to monitor the adequacy of therapy. Gonzalez et al. compared PAC thermodilution cardiac output with indirect Fick measures of cardiac output. They found that at lower cardiac outputs (< 5 l/min) the agreement between the two techniques is good, whereas at higher flows increased differences exist between the two measures. As discussed in this commentary, this study did not address the three potential questions related to PAC monitoring of cardiac output. These questions are: can the PAC cardiac output data be used to monitor cardiac output? Do technical and physiological constraints limit the accuracy of PAC cardiac output? And; are PAC cardiac output measurement errors due to respiratory variation in pulmonary blood flow? Ways of answering each question are given.

Effect of calpain inhibitor I, an inhibitor of the proteolysis of I kappa B, on the circulatory failure and multiple organ dysfunction caused by endotoxin in the rat

1. We compared the effects of calpain inhibitor I (inhibitor of the proteolysis of I kappa B and, hence, of the activation of nuclear factor kappa B (NF kappa B) and dexamethasone on (i) the circulatory failure, (ii) multiple organ dysfunction and (iii) induction of the inducible isoforms of nitric oxide (NO) synthase (iNOS) and cyclo-oxygenase (COX-2) in anaesthetized rats with endotoxic shock. 2. Injection of lipopolysaccharide (LPS, E. coli, 10 mg kg-1, i.v.) resulted in hypotension and a reduction of the pressor responses elicited by noradrenaline. This circulatory dysfunction was attenuated by pretreatment of LPS-rats with calpain inhibitor I (10 mg kg-1, i.v., 2 h before LPS) or dexamethasone (1 mg kg-1, i.v.). 3. Endotoxaemia also caused rises in the serum levels of (i) urea and creatinine (renal dysfunction), (ii) alanine aminotransferase (ALT), aspartate aminotransferase (AST) (hepatocellular injury), bilirubin and gamma-glutamyl transferase (gamma GT) (liver dysfunction), (iii) lipase (pancreatic injury) and (iv) lactate. Calpain inhibitor I and dexamethasone attenuated the liver injury, the pancreatic injury, the lactic acidosis as well as the hypoglycaemia caused by LPS. Dexamethasone, but not calpain inhibitor I, reduced the renal dysfunction caused by LPS. 4. Endotoxaemia for 6 h resulted in a substantial increase in iNOS and COX-2 protein and activity in lung and liver, which was attenuated in LPS-rats pretreated with calpain inhibitor I or dexamethasone. 5. Thus, calpain inhibitor I and dexamethasone attenuate (i) the circulatory failure, (ii) the multiple organ dysfunction (liver and pancreatic dysfunction/injury, lactic acidosis, hypoglycaemia), as well as (iii) the induction of iNOS and COX-2 protein and activity in rats with endotoxic shock. We propose that prevention of the activation of NF-kappa B in vivo may be useful in the therapy of circulatory shock or of disorders associated with local or systemic inflammation.