[Laboratory and calorimetric monitoring of medical nutrition therapy in intensive and intermediate care units : Second position paper of the Section Metabolism and Nutrition of the German Interdisciplinary Association for Intensive Care and Emergency Medicine (DIVI)]

This second position paper of the Section Metabolism and Nutrition of the German Interdisciplinary Association for Intensive Care and Emergency Medicine (DIVI) provides recommendations on the laboratory monitoring of macro- and micronutrient intake as well as the use of indirect calorimetry in the context of medical nutrition therapy of critically ill adult patients. In addition, recommendations are given for disease-related or individual (level determination) substitution and (high-dose) pharmacotherapy of vitamins and trace elements.

Progranulin signaling in sepsis, community-acquired bacterial pneumonia and COVID-19: a comparative, observational study

Background

Progranulin is a widely expressed pleiotropic growth factor with a central regulatory effect during the early immune response in sepsis. Progranulin signaling has not been systematically studied and compared between sepsis, community-acquired pneumonia (CAP), COVID-19 pneumonia and a sterile systemic inflammatory response (SIRS). We delineated molecular networks of progranulin signaling by next-generation sequencing (NGS), determined progranulin plasma concentrations and quantified the diagnostic performance of progranulin to differentiate between the above-mentioned disorders using the established biomarkers procalcitonin (PCT), interleukin-6 (IL-6) and C-reactive protein (CRP) for comparison.

Methods

The diagnostic performance of progranulin was operationalized by calculating AUC and ROC statistics for progranulin and established biomarkers in 241 patients with sepsis, 182 patients with SIRS, 53 patients with CAP, 22 patients with COVID-19 pneumonia and 53 healthy volunteers. miRNAs and mRNAs in blood cells from sepsis patients (n = 7) were characterized by NGS and validated by RT-qPCR in an independent cohort (n = 39) to identify canonical gene networks associated with upregulated progranulin at sepsis onset.

Results

Plasma concentrations of progranulin (ELISA) in patients with sepsis were 57.5 (42.8–84.9, Q25–Q75) ng/ml and significantly higher than in CAP (38.0, 33.5–41.0 ng/ml, p < 0.001), SIRS (29.0, 25.0–35.0 ng/ml, p < 0.001) and the healthy state (28.7, 25.5–31.7 ng/ml, p < 0.001). Patients with COVID-19 had significantly higher progranulin concentrations than patients with CAP (67.6, 56.6–96.0 vs. 38.0, 33.5–41.0 ng/ml, p < 0.001). The diagnostic performance of progranulin for the differentiation between sepsis vs. SIRS (n = 423) was comparable to that of procalcitonin. AUC was 0.90 (95% CI = 0.87–0.93) for progranulin and 0.92 (CI = 0.88–0.96, p = 0.323) for procalcitonin. Progranulin showed high discriminative power to differentiate bacterial CAP from COVID-19 (sensitivity 0.91, specificity 0.94, AUC 0.91 (CI = 0.8–1.0) and performed significantly better than PCT, IL-6 and CRP. NGS and partial RT-qPCR confirmation revealed a transcriptomic network of immune cells with upregulated progranulin and sortilin transcripts as well as toll-like-receptor 4 and tumor-protein 53, regulated by miR-16 and others.

Conclusions

Progranulin signaling is elevated during the early antimicrobial response in sepsis and differs significantly between sepsis, CAP, COVID-19 and SIRS. This suggests that progranulin may serve as a novel indicator for the differentiation between these disorders.

Trial registration: Clinicaltrials.gov registration number NCT03280576 Registered November 19, 2015.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40635-021-00406-7.

Clinical Nutrition in Critical Care Medicine - Guideline of the German Society for Nutritional Medicine (DGEM)

PURPOSE

Enteral and parenteral nutrition of adult critically ill patients varies in terms of the route of nutrient delivery, the amount and composition of macro- and micronutrients, and the choice of specific, immune-modulating substrates. Variations of clinical nutrition may affect clinical outcomes. The present guideline provides clinicians with updated consensus-based recommendations for clinical nutrition in adult critically ill patients who suffer from at least one acute organ dysfunction requiring specific drug therapy and/or a mechanical support device (e.g., mechanical ventilation) to maintain organ function.

METHODS

The former guidelines of the German Society for Nutritional Medicine (DGEM) were updated according to the current instructions of the Association of the Scientific Medical Societies in Germany (AWMF) valid for a S2k-guideline. According to the S2k-guideline classification, no systematic review of the available evidence was required to make recommendations, which, therefore, do not state evidence- or recommendation grades. Nevertheless, we considered and commented the evidence from randomized-controlled trials, meta-analyses and observational studies with adequate sample size and high methodological quality (until May 2018) as well as from currently valid guidelines of other societies. The liability of each recommendation was described linguistically. Each recommendation was finally validated and consented through a Delphi process.

RESULTS

In the introduction the guideline describes a) the pathophysiological consequences of critical illness possibly affecting metabolism and nutrition of critically ill patients, b) potential definitions for different disease phases during the course of illness, and c) methodological shortcomings of clinical trials on nutrition. Then, we make 69 consented recommendations for essential, practice-relevant elements of clinical nutrition in critically ill patients. Among others, recommendations include the assessment of nutrition status, the indication for clinical nutrition, the timing and route of nutrient delivery, and the amount and composition of substrates (macro- and micronutrients); furthermore, we discuss distinctive aspects of nutrition therapy in obese critically ill patients and those treated with extracorporeal support devices.

CONCLUSION

The current guideline provides clinicians with up-to-date recommendations for enteral and parenteral nutrition of adult critically ill patients who suffer from at least one acute organ dysfunction requiring specific drug therapy and/or a mechanical support device (e.g., mechanical ventilation) to maintain organ function. The period of validity of the guideline is approximately fixed at five years (2018-2023).

[DGEM Guideline "Clinical Nutrition in Critical Care Medicine" - short version]

PURPOSE

Variations of clinical nutrition may affect outcome of critically ill patients. Here we present the short version of the updated consenus-based guideline (S2k classification) "Clinical nutrition in critical care medicine" of the German Society for Nutritional Medicine (DGEM) in cooperation with 7 other national societies. The target population of the guideline was defined as critically ill adult patients who suffer from at least one acute organ dysfunction requiring specific drug therapy and/or a mechanical support device (e.g. mechanical ventilation) to maintain organ function.

METHODS

The former guidelines of the German Society for Nutritional Medicine (DGEM) were updated according to the current instructions of the Association of the Scientific Medical Societies in Germany (AWMF) valid for a S2k-guideline. We considered and commented the evidence from randomized-controlled trials, meta-analyses and observational studies with adequate sample size and high methodological quality (until May 2018) as well as from currently valid guidelines of international societies. The liability of each recommendation was indicated using linguistic terms. Each recommendation was finally validated and consented by a Delphi process.

RESULTS

The short version presents a summary of all 69 consented recommendations for essential, practice-relevant elements of clinical nutrition in the target population. A specific focus is the adjustment of nutrition according to the phases of critical illness, and to the individual tolerance to exogenous substrates. Among others, recommendations include the assessment of nutritional status, the indication for clinical nutrition, the timing, route, magnitude and composition of nutrition (macro- and micronutrients) as well as distinctive aspects of nutrition therapy in obese critically ill patients and those with extracorporeal support devices.

CONCLUSION

The current short version of the guideline provides a concise summary of the updated recommendations for enteral and parenteral nutrition of adult critically ill patients who suffer from at least one acute organ dysfunction requiring pharmacological and/or mechanical support. The validity of the guideline is approximately fixed at five years (2018 - 2023).

DGEM-Leitlinie: „Klinische Ernährung in der Intensivmedizin“

Fragestellung Die enterale und parenterale Ernährungstherapie kritisch kranker Patienten kann u. a. durch den Zeitpunkt des Beginns, die Wahl des Applikationswegs, die Menge und Zusammensetzung der Makro- und Mikronährstoffzufuhr sowie der Wahl spezieller, immunmodulierender Nährsubstrate variieren. Die Durchführung der Ernährungstherapie nimmt Einfluss auf den klinischen Ausgang dieser Patienten. Ziel der vorliegenden Leitlinie ist es, aktualisierte konsensbasierte Empfehlungen zur klinischen Ernährung kritisch kranker, erwachsener Patienten, die an mindestens einer akuten, medikamentös und/oder mechanisch unterstützungspflichtigen Organdysfunktion leiden, zu geben.

Methodik Die früheren Leitlinien der Deutschen Gesellschaft für Ernährungsmedizin (DGEM) wurden in Einklang mit den aktuellen Richtlinien der Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e. V. (AWMF) als S2k-Leitlinie aktualisiert. Entsprechend der S2k-Klassifikation dieser Leitlinie enthalten die dargestellten Empfehlungen keine Angabe von Evidenz- und Empfehlungsgraden, da keine systematische Aufbereitung der Evidenz zugrunde gelegt wurde. Als Grundlage für die Empfehlungen wurden insbesondere die seit Erscheinen der letzten DGEM-Leitlinien Intensivmedizin publizierten randomisiert-kontrollierten Studien und Metaanalysen, Beobachtungsstudien mit angemessener Fallzahl und hoher methodologischer Qualität (bis Mai 2018) sowie aktuell gültige Leitlinien anderer Fachgesellschaften herangezogen und kommentiert. Die Empfehlungsstärke ist rein sprachlich beschrieben. Jede Empfehlung wurde mittels Delphi-Verfahren abschließend bewertet und konsentiert.

Ergebnisse Die Leitlinie beschreibt einführend die pathophysiologischen Konsequenzen einer kritischen Erkrankung, welche den Metabolismus und die Ernährbarkeit der Patienten beeinflussen können, ferner die Definitionen unterschiedlicher Erkrankungsphasen im Krankheitsverlauf und sie diskutiert methodologische Aspekte zu ernährungsmedizinischen Studien. In der Folge werden 69 konsentierte Empfehlungen zu wesentlichen, praxisrelevanten Elementen der klinischen Ernährung kritisch kranker Patienten gegeben, darunter die Beurteilung des Ernährungszustands, die Indikation für die klinische Ernährungstherapie, der Beginn und Applikationsweg der Nahrungszufuhr, die Menge und Art der zugeführten Substrate (Makro- und Mikronährstoffe) sowie ernährungstherapeutische Besonderheiten bei adipösen kritisch kranken Patienten und Patienten mit mechanischen Unterstützungssystemen.

Schlussfolgerung Mit der Leitlinie werden aktuelle Handlungsempfehlungen zur enteralen und parenteralen Ernährung erwachsener Patienten geben, die an mindestens einer akuten, medikamentös und/oder mechanisch unterstützungspflichtigen Organdysfunktion leiden. Die Gültigkeit der Leitlinie beträgt voraussichtlich 5 Jahre (2018 – 2023).

Gastrointestinal dysmotility in the critically ill: a role for nutrition

PURPOSE OF REVIEW

The role of enteral nutrition on gastrointestinal dysmotility in the critically ill remains controversial.

RECENT FINDINGS

The mechanisms of gastrointestinal dysmotility during critical illness remain poorly investigated. Low amounts of enteral feeding stimulate motility and have trophic effects. Therefore, enteral feeding is feasible even during gastrointestinal dysmotility as seen in the hemodynamically compromised patient. Rapid 'ramp-up' of administration rate of tube feeding bears the risk of overload and even detrimental ischemic bowel necrosis. The recent American Society for Parenteral and Enteral Nutrition guidelines do not recommend the measurement of gastric residual volume. The use of concentrated enteral solutions with 1.5 kcal/ml may result in greater calorie delivery. Biomarkers like plasma citrulline and plasma or urine intestinal fatty-acid-binding protein reflect the functional integrity of the bowel and may potentially support monitoring.

SUMMARY

To improve enteral nutrition protocols, the definitions of gastrointestinal dysfunction, gastric dysmotility, and feeding intolerance should be clearly defined in the future. In the concept of integrity of the gut, enteral nutrition should not be stopped completely during gastrointestinal dysfunction but restricted to a 'minimal' trophic feeding rate. In malnourished and high-risk patients intolerant to enteral feeding supplemental parenteral nutrition should be started on day 4 or earlier.

Elevated Values of Clinically Relevant Transferases Induced by Imported Infectious Diseases: A Controlled Cross-Sectional Study of 14,559 Diseased German Travelers Returning from the Tropics and Subtropics

The aim of this controlled cross-sectional study was to assess the clinical validity of elevated values of three clinically relevant transferase enzymes (aspartate transaminase [AST], alanine transaminase [ALT], and gamma-glutamyl transferase [GGT]) induced by imported infectious diseases (IDs) seen among patients consulting the Division of Infectious Diseases and Tropical Medicine, Medical Center of the University of Munich (from 1999 to 2014) after being in the sub-/tropics. Data sets of 14,559 diseased German travelers returning from Latin America (2,715), Africa (4,574), or Asia (7,270) and of 1,536 healthy controls of German origin without recent travels were analyzed. Among the cases, the proportions of those with elevated values of AST (7.8%) and of ALT (13.4%) were significantly larger than among controls (4.0% and 10.6%, respectively), whereas for GGT, no significant difference was found (cases: 10.0%; controls: 11.4%). The study identified IDs with significantly larger proportions of both AST and ALT (hepatitis A [100%/100%], cytomegalovirus [CMV] infection [77%/81%], chronic hepatitis C [67%/67%], infectious mononucleosis [65%/77%], typhoid fever [50%/50%], cyclosporiasis [45%/66%], dengue fever [43%/35%], malaria [20%/27%], and rickettsiosis [20%/24%]), of AST alone (paratyphoid fever [42%]), of ALT alone (giardiasis [20%]), and of GGT (hepatitis A [100%], infectious mononucleosis [71%], CMV infection [58%], rickettsiosis (20%], and dengue fever [19%]). The study demonstrates that the determination of AST and ALT among travelers returning from the sub-/tropics has a high clinical validity, as their elevated values are typically caused by several imported viral, bacterial, and protozoan IDs, whereas no additional clinical validity was found by the determination of GGT.

Gastric residual volume in critically ill patients: a dead marker or still alive?

Early enteral nutrition (EN) is consistently recommended as first-line nutrition therapy in critically ill patients since it favorably alters outcome, providing both nutrition and nonnutrition benefits. However, critically ill patients receiving mechanical ventilation are at risk for regurgitation, pulmonary aspiration, and eventually ventilator-associated pneumonia (VAP). EN may increase these risks when gastrointestinal (GI) dysfunction is present. Gastric residual volume (GRV) is considered a surrogate parameter of GI dysfunction during the progression of enteral feeding in the early phase of critical illness and beyond. By monitoring GRV, clinicians may detect patients with delayed gastric emptying earlier and intervene with strategies that minimize or prevent VAP as one of the major risks of EN. The value of periodic GRV measurements with regard to risk reduction of VAP incidence has frequently been questioned in the past years. Increasing the GRV threshold before interrupting gastric feeding results in marginal increases in EN delivery. More recently, a large randomized clinical trial revealed that abandoning GRV monitoring did not negatively affect clinical outcomes (including VAP) in mechanically ventilated patients. The results have revived the discussion on the role of GRV monitoring in critically ill, mechanically ventilated patients receiving early EN. This review summarizes the most recent clinical evidence on the use of GRV monitoring in critically ill patients. Based on the clinical evidence, it discusses the pros and cons and further addresses whether GRV is a dead marker or still alive for the nutrition management of critically ill patients.

Group A Streptococci: A rare and often misdiagnosed cause of spontaneous bacterial peritonitis in adults

•

We present three different and well-described cases of severe GAS peritonitis.

•

We give a review of current literature.

•

We highlight the difficulties in treatment and diagnostics.

Introduction

Acute primary peritonitis due to group A Streptococci (GAS) is a rare but life-threatening infection. Unlike other forms of primary peritonitis it affects predominantly young previously healthy individuals and thus is often confused with the more frequent secondary peritonitis. A case series of three patients is presented as well as a review of the literature focusing on pitfalls in the diagnose and therapy of GAS peritonitis.

Methods

A retrospective analysis of three patients with primary GAS peritonitis was performed. Furthermore a systematic review of all cases of primary GAS peritonitis published from 1990 to 2013 was performed comparing demographics and clinical presentation, as well as radiological imaging, treatment and outcome.

Results

All three female patients presented initially with high fever, nausea and severe abdominal pain. Radiological imaging revealed intraperitoneal fluid collections of various degrees, but no underlying cause of peritonitis. Broad antibiotic treatment was started and surgical exploration was performed for acute abdomen in all three cases. Intraoperatively fibrinous peritonitis was observed, but the correct diagnosis was not made until microbiological analysis confirmed GAS peritonitis. One patient died within 24 h after admission. The other two patients recovered after multiple surgeries and several weeks on the intensive care unit due to multiple organ dysfunction syndrome. The fulminant clinical course of the three patients resembled those of many of the published cases: flu-like symptoms, high fever, severe acute abdominal pain and fibrinous peritonitis without obvious infectious focus were the most common symptoms reported in the literature.

Conclusion

GAS primary peritonitis should be considered in particular in young, previously healthy women who present with peritonitis but lack radiological findings of an infectious focus. The treatment of choice is immediate antibiotic therapy. Surgical intervention is difficult to avoid, since the diagnosis of GAS peritonitis is usually not confirmed until other causes of secondary peritonitis have been excluded.

High-protein enteral nutrition enriched with immune-modulating nutrients vs standard high-protein enteral nutrition and nosocomial infections in the ICU: a randomized clinical trial

IMPORTANCE

Enteral administration of immune-modulating nutrients (eg, glutamine, omega-3 fatty acids, selenium, and antioxidants) has been suggested to reduce infections and improve recovery from critical illness. However, controversy exists on the use of immune-modulating enteral nutrition, reflected by lack of consensus in guidelines.

OBJECTIVE

To determine whether high-protein enteral nutrition enriched with immune-modulating nutrients (IMHP) reduces the incidence of infections compared with standard high-protein enteral nutrition (HP) in mechanically ventilated critically ill patients.

DESIGN, SETTING, AND PARTICIPANTS

The MetaPlus study, a randomized, double-blind, multicenter trial, was conducted from February 2010 through April 2012 including a 6-month follow-up period in 14 intensive care units (ICUs) in the Netherlands, Germany, France, and Belgium. A total of 301 adult patients who were expected to be ventilated for more than 72 hours and to require enteral nutrition for more than 72 hours were randomized to the IMHP (n = 152) or HP (n = 149) group and included in an intention-to-treat analysis, performed for the total population as well as predefined medical, surgical, and trauma subpopulations.

INTERVENTIONS

High-protein enteral nutrition enriched with immune-modulating nutrients vs standard high-protein enteral nutrition, initiated within 48 hours of ICU admission and continued during the ICU stay for a maximum of 28 days.

MAIN OUTCOMES AND MEASURES

The primary outcome measure was incidence of new infections according to the Centers for Disease Control and Prevention (CDC) definitions. Secondary end points included mortality, Sequential Organ Failure Assessment (SOFA) scores, mechanical ventilation duration, ICU and hospital lengths of stay, and subtypes of infections according CDC definitions.

RESULTS

There were no statistically significant differences in incidence of new infections between the groups: 53% (95% CI, 44%-61%) in the IMHP group vs 52% (95% CI, 44%-61%) in the HP group (P = .96). No statistically significant differences were observed in other end points, except for a higher 6-month mortality rate in the medical subgroup: 54% (95% CI, 40%-67%) in the IMHP group vs 35% (95% CI, 22%-49%) in the HP group (P = .04), with a hazard ratio of 1.57 (95% CI, 1.03-2.39; P = .04) for 6-month mortality adjusted for age and Acute Physiology and Chronic Health Evaluation II score comparing the groups.

CONCLUSIONS AND RELEVANCE

Among adult patients breathing with the aid of mechanical ventilation in the ICU, IMHP compared with HP did not improve infectious complications or other clinical end points and may be harmful as suggested by increased adjusted mortality at 6 months. These findings do not support the use of IMHP nutrients in these patients.

TRIAL REGISTRATION

trialregister.nl Identifier: NTR2181.

[Nutrition of the critically ill - is less more? How much energy for the ICU patient?]

Decreased nutritional intake or preexisting malnutrition is associated with increased morbidity and mortality during hospital stay. However nutritional support in particular for the ICU patient is not trivial. Hyperalimentation in the acute phase of critical illness but also hypoalimentation in the chronic and stable phase of illness has to be avoided. Ideally about 25 kcal/kg/d should be targeted over a few days during metabolic monitoring. Alternatively indirect calorimetry should be applied where available.

[Update glutamine and antioxidants in critically ill patients]

Critical illness leads to oxidative stress and can induce or exacerbate nutrient deficiencies. This predisposes patients in the intensive care unit to impaired immune function and increased risk of developing infectious complications, organ dysfunction, and therefore worsens clinical outcome. Immune-modulating properties of specific nutrients such as glutamine and antioxidants may support the endogenous antioxidative system, improve immune and organ function and translate into better clinical outcome of the critically ill patient. The following article summarizes the rationale and provides an update on recent clinical studies with special focus on the use of glutamine and antioxidants in critically ill patients. It further provides recommendations for the clinical use of these substrates in this particular patient population.

[Nutrition and acute respiratory failure]

Acute respiratory distress syndrome (ARDS) is characterized by the formation of a protein-rich alveolar edema caused by increased permeability of the alveolocapillary membrane. The key clinical feature is refractory arterial hypoxemia, which in severe cases necessitates the application of extracorporeal membrane oxygenation. Besides lung-protective ventilation as a confirmed therapeutic option, supportive therapy is an integral part of ARDS management. In this context, modern and individualized nutritional regimens are of special importance; however, their prognostic impact, especially of immunonutrition, for ARDS patients is controversial. In this review, basic features of nutrition in intensive care medicine and ARDS-specific aspects (e.g., immunonutrition) are presented and discussed.

[Immunonutrition after trauma]

Immunonutrition may be superior to standard clinical nutrition in specific clinical situations. After severe trauma, an enteral immuno-enhancing diet, enriched with arginine, omega-3 fatty acids, and nucleotides, decreases infectious complications. During acute respiratory distress syndrome, a continuous enteral diet with high-dose omega-3 fatty acids, gamma-linolenic acid, and antioxidants improved clinical outcome. Glutamine should be administered enterally or parenterally whenever total parenteral nutrition is indicated.

Suctioning via the tube during endotracheal intubation in a model of severe upper airway haemorrhage: is there an advantage vs. suctioning with a separate catheter?

INTRODUCTION

In a model of severe simulated upper airway haemorrhage, we compared two techniques of performing endotracheal intubation: (1) suctioning via the endotracheal tube during laryngoscopy with subsequently advancing the endotracheal tube, and (2) the standard intubation strategy with performing laryngoscopy, and performing suction with subsequently advancing the endotracheal tube.

METHODS

Forty-one emergency medical technicians intubated the trachea of a manikin with severe simulated airway haemorrhage using each technique in random order.

RESULTS

There was no significant difference in the number of oesophageal intubations between suctioning via the tube and the standard intubation strategy [8/41 (20%) vs. 6/41 (15%); P = 0.688], but suctioning via the endotracheal tube needed significantly more time [median (IQR, CI 95%): 42 (20, 39-60) vs. 33 (15, 35-48)s; P = 0.015].

CONCLUSIONS

Suctioning via the endotracheal tube showed no benefit regarding the number of oesophageal intubations and needed more time when compared to the standard intubation strategy.

A comparison of the suction laryngoscope and the Macintosh laryngoscope in emergency medical technicians: a manikin model of severe airway haemorrhage

The use of a suction laryngoscope that enables simultaneous suction and laryngoscopy was evaluated. 34 emergency medical technicians intubated the trachea of a manikin with simulated upper airway haemorrhage using the suction laryngoscope and the Macintosh laryngoscope, in random order. When using the suction laryngoscope, the number of oesophageal intubations was lower (3/34 vs 11/34; p=0.021) and the time taken to intubation was shorter (mean (SD) 50 (15) vs 58 (27) s; p=0.041). In cases of airway haemorrhage, the use of the suction laryngoscope might be beneficial.

Laparoscopic splenectomy in a pregnant patient with immune thrombocytopenic purpura

We describe the perioperative management of a pregnant woman at 19 weeks' gestation with idiopathic thrombocytopenic purpura requiring laparoscopic splenectomy. The preoperative platelet count ranged between 1 and 5 x 10(9)/L and did not respond to conventional medical therapy. To reduce the risk of intracerebral hemorrhage, platelets were transfused before induction of anesthesia to maintain platelet count closer to 20 x 10(9)/L. The blood pressure was monitored continuously via an arterial line and remifentanil was infused to prevent a hypertensive response to induction/intubation, carbon dioxide insufflation, and surgery. After the splenic artery was clamped, additional platelet units were transfused to assure surgical hemostasis.

ICAM-1 and beta2 integrin deficiency impairs fat oxidation and insulin metabolism during fasting

Intercellular adhesion molecule 1 (ICAM-1) and beta2 integrins play critical roles in immune responses. ICAM-1 may also participate in regulation of energy balance because ICAM-1-deficient mice become obese on a high-fat diet. We show that mice deficient in these adhesion receptors are unable to respond to fasting by up-regulation of fatty acid oxidation. Normal mice, when fasted, exhibit reduced circulating neutrophil counts and increased ICAM-1 expression and neutrophil recruitment in liver. Mice lacking ICAM-1 or beta2 integrins fail to show these responses--instead they become hypoglycemic with steatotic livers. Fasting ICAM-1-deficient mice reduce insulin more slowly than wild-type mice. This produces fasting hyperinsulinemia that prevents activation of adenosine mono-phosphate (AMP)-activated protein kinase in muscles and liver, which results in decreased import of long chain fatty acids into mitochondria. Thus, we show a new role for immune cells and their adhesion receptors in regulating metabolic response to fasting.

Perioperative Echokardiographie

Over the past decades, echocardiography has undergone a continuous evolution in technology that has promoted its clinical application and acceptance throughout perioperative medicine. These technological advances include improvements in transducer development that permit superior imaging quality and a wider selection of probes for epicardial, epiaortic, and surface echocardiography which can also be used in conjunction with multiplane transesophageal echocardiography. Moreover, the addition of Doppler technology and digital acquisition has secured the role of echocardiography as a valuable and relatively noninvasive diagnostic tool for the assessment of cardiovascular disease and hemodynamic monitoring throughout the perioperative period. Therefore, it has become increasingly important for perioperative physicians to understand the basic principles and underlying fundamental concepts pertaining to the technology and physics of echocardiography, as well as its inherent limitations. The current review outlines the modes and applications of different echocardiographic techniques used in perioperative echocardiography including M-mode, two-dimensional echocardiography, and Doppler assessment of blood flow. In addition, the limitations of these techniques and typical artifacts associated with the perioperative use of echocardiography are described.

Arterielle Pulskonturanalyse zur Messung des Herzindex unter Veränderungen der Vorlast und der aortalen Impedanz

BACKGROUND

Cardiac index obtained by arterial pulse contour analysis (CI(PC)) demonstrated good agreement with arterial or pulmonary arterial thermodilution derived cardiac index (CI(TD), CI(PA)) in cardiac surgical or critically ill patients. However as the accuracy of pulse contour analysis during changes of the aortic impedance is unclear, we compared CI(PC), CI(TD) and CI(PA) during changes of preload and the aortic impedance as occurring during sternotomy.

PATIENTS AND METHODS

CI(PC) und CI(TD), were compared in 28 patients, (and CI(PA) in 6 patients) undergoing elective coronary artery bypass grafting, before and after sternotomy. The relative changes DeltaCI(PC) und DeltaCI(PC) were calculated.

RESULTS

Sternotomy resulted in a significant increase in CI in 25 out of 28 patients. Regression analysis was performed between CI(PC) and CI(TD) before and after sternotomy (r(2) = 0.87, p<0.0001, r(2) = 0.88, p<0.0001) as well as between CI(PC) and CI(PA), before and after sternotomy (r(2) = 0.85, p<0.0001, r(2) = 0.93, p<0.01) and between DeltaCI(PC) and DeltaCI(TD) (r(2) = 0.72, p<0.0001). Bland Altman-Analysis for determining bias (m) and precision (2SD) between CI(PC) and CI(TD) before and after sternotomy and between DeltaCI(PC) and DeltaCI(TD) resulted in m = -0.03 L/min/m(2), 2SD = -0.34 to 0.28 L/min/m(2), m = -0.06 L/min/m(2), 2SD = -0.45 to 0.33 L/min/m(2) and m = -0.02 L/min/m(2), SD = -0.47 to 0.44 L/min/m(2).

CONCLUSION

Pulse contour analysis derived CI(PC) accurately reflects thermodilution derived CI(TD) or CI(PA) during changes of preload and the aortic impedance as occurring during sternotomy.

Cardiac index measurements during rapid preload changes: a comparison of pulmonary artery thermodilution with arterial pulse contour analysis

STUDY OBJECTIVE

To compare cardiac index (CI) values obtained by pulmonary artery thermodilution (CIPA), arterial thermodilution (CITD), and arterial pulse contour analysis (CIPC) during rapid fluid administration, as accurate and rapid detection of CI changes is critical during acute preload changes for guiding volume and vasopressor therapy in critically ill patients, and the accuracy of CIPC during acute changes in loading condition is currently unknown.

DESIGN

Prospective clinical study.

SETTING

Cardiac surgical intensive care unit of a university hospital.

PATIENTS

Seventeen American Society of Anesthesiologists (ASA) physical status II and III patients, aged 32 to 76 years, with normal left ventricular function during the early postoperative period after elective coronary artery bypass graft surgery.

MEASUREMENTS

After baseline determinations of CIPA, CIPC, and CITD were made, fluid loading was performed using 10 mL times body mass index of hydroxyethyl starch 6%. CIPA, CIPC, and CITD were determined, and changes in CI (DeltaCI) were calculated. Fluid load was repeated until no increase in stroke volume index (DeltaSVI <10%) was achieved.

MAIN RESULTS

Regression analysis between CIPA/CIPC, CIPA/CITD, and CIPC/CITD revealed r2 = 0.92, r2 = 0.92, and r2 = 0.98. Regression analysis between DeltaCIPA/DeltaCIPC, DeltaCIPA/DeltaCITD, and DeltaCIPC/DeltaCITD revealed r2 = 0.57, r2 = 0.67, and r2 = 0.74, respectively. Bland-Altman analysis was used to determine accuracy and precision of the 3 methods compared. The mean differences (m) and SD between DeltaCIPA/DeltaCIPC, DeltaCIPA/DeltaCITD, and DeltaCIPC/DeltaCITD resulted in m = -1.01%, SD = 6.51%; m = -0.83%, SD = 5.80%; and m = -0.33%, SD = 4.65%, respectively.

CONCLUSION

Compared with pulmonary artery thermodilution, arterial pulse contour analysis reflects relative changes in CI during rapid changes of preload with clinically acceptable accuracy.

Ketamine for long-term sedation and analgesia of a burn patient

We present a case in which ketamine was used for long-term sedation and analgesia of a burn patient. Under escalating opiate dosages, the patient had developed persistent ileus as well as abdominal distension that caused respiratory compromise, without receiving sufficient analgesia. The opiate-sparing effect of the continuous ketamine infusion was more than 90%. The ileus resolved within 24 h. The quality of sedation also changed favorably. There were no obvious adverse effects of ketamine.

CXCL12 mediates CCR7-independent homing of central memory cells, but not naive T cells, in peripheral lymph nodes

Central memory CD8(+) T cells (T(CM)) confer superior protective immunity against infections compared with other T cell subsets. T(CM) recirculate mainly through secondary lymphoid organs, including peripheral lymph nodes (PLNs). Here, we report that T(CM), unlike naive T cells, can home to PLNs in both a CCR7-dependent and -independent manner. Homing experiments in paucity of lymph node T cells (plt/plt) mice, which do not express CCR7 ligands in secondary lymphoid organs, revealed that T(CM) migrate to PLNs at approximately 20% of wild-type (WT) levels, whereas homing of naive T cells was reduced by 95%. Accordingly, a large fraction of endogenous CD8(+) T cells in plt/plt PLNs displayed a T(CM) phenotype. Intravital microscopy of plt/plt subiliac lymph nodes showed that T(CM) rolled and firmly adhered (sticking) in high endothelial venules (HEVs), whereas naive T cells were incapable of sticking. Sticking of T(CM) in plt/plt HEVs was pertussis toxin sensitive and was blocked by anti-CXCL12 (SDF-1alpha). Anti-CXCL12 also reduced homing of T(CM) to PLNs in WT animals by 20%, indicating a nonredundant role for this chemokine in the presence of physiologic CCR7 agonists. Together, these data distinguish naive T cells from T(CM), whereby only the latter display greater migratory flexibility by virtue of their increased responsiveness to both CCR7 ligands and CXCL12 during homing to PLN.

Epikardiale Echokardiographie

Epicardial echocardiography has been available since the early 1970s as an intraoperative diagnostic modality to assess ventricular and valvular function. With this technique, an ultrasonic transducer is placed directly on the epicardial surface of the heart, following sternotomy and pericardiotomy. Under the guidance of the cardiac anesthesiologist, the surgeon places the transducer so that the desired views of cardiac structures and great vessels can be obtained. The anesthesiologist performs the acquisition, analysis and interpretation of the echocardiographic images. Despite the feasibility of epicardial echocardiography, transesophageal echocardiography (TEE) has emerged over the last two decades as the main form of intraoperative echocardiography. Although TEE allows continuous monitoring of cardiac and valvular function without interruption of the surgical procedure, placement of a TEE probe may be difficult or contraindicated in some patients. In such cases, epicardial echocardiography may be the optimal ultrasonographic imaging modality to assess ventricular and valvular function during cardiac surgery. We describe the use of epicardial echocardiography for intraoperative assessment of valvular function in two patients where TEE was either contraindicated or probe placement could not be performed safely. The first patient underwent surgical repair of the mitral valve for severe mitral regurgitation. After weaning the patient from cardiopulmonary bypass (CPB), epicardial echocardiography was used to confirm successful reconstruction of the valve and to exclude residual mitral regurgitation. The second patient was scheduled for coronary artery bypass grafting (CABG). Prior to the initiation of CPB, the presence of moderate aortic stenosis was confirmed using Doppler echocardiography via an epicardial approach.

[Perioperative implications of heart transplant]

Over the past 30 years, heart transplantation has evolved into a definitive therapy for patients with end-stage cardiomyopathy. However, perioperative management of patients undergoing heart transplantation remains a challenge for anesthesiologists. The presence of biventricular failure, arrhythmias and associated multisystem organ dysfunction may contribute to significant intraoperative hemodynamic instability prior to the initiation of cardiopulmonary bypass (CPB). Even after an uneventful transplantation, weaning from CPB may be difficult. Acute right ventricular failure can develop in the recipient secondary to pre-existing pulmonary hypertension. Treatment options frequently focus on therapeutic interventions directed towards decreasing pulmonary vascular resistance and improving right ventricular contractility. Intraoperative use of transesophageal echocardiography (TEE) enables the anesthesiologist to diagnose acute right ventricular failure early on and guide therapy. Concurrent pathology including kinking of the pulmonary artery anastomosis or valvular insufficiency in the transplanted heart can also be recognized and addressed. The number of patients undergoing cardiac transplantation is continually increasing. In addition, the use of more effective immunosuppressive agents has curtailed transplant rejection and permitted longer survival. Consequently, heart transplant recipients are more frequently presenting for non-cardiac surgical procedures. Thus, an understanding of physiological and pharmacological implications associated with heart transplantation is crucial for managing these patients in the perioperative period.

Usefulness of left ventricular stroke volume variation to assess fluid responsiveness in patients with reduced cardiac function

OBJECTIVE

Stroke volume variation as measured by the analysis of the arterial pressure waveform enables prediction of volume responsiveness in ventilated patients with normal cardiac function. The aim of this study was to investigate the ability of monitoring stroke volume variation to predict volume responsiveness and to assess changes in preload in patients with reduced left ventricular function after cardiac surgery.

DESIGN

Prospective study.

SETTING

University hospital.

PATIENTS

Fifteen mechanically ventilated patients with a left ventricular ejection fraction <0.35 (study group) and 15 patients with an ejection fraction >0.50 (control group) after coronary artery bypass grafting following admission to the intensive care unit.

INTERVENTIONS

Volume loading with 10 mL of hetastarch 6% times body mass index. If stroke volume index increased >5%, successive volume loading was performed until no further increase in stroke volume index was reached.

MEASUREMENTS AND MAIN RESULTS

Stroke volume variation, central venous pressure, pulmonary artery occlusion pressure (PAOP), and left ventricular end-diastolic area index (LVEDAI) were measured at baseline and immediately after each volume loading step. In both groups, stroke volume variation at baseline correlated significantly with changes in stroke volume index caused by volume loading (p <.01). Further, changes in stroke volume variation as a result of volume loading correlated significantly with the concomitant changes in stroke volume index in both groups (p <.01). Using receiver operating characteristic analysis, in the study group areas under the curve for stroke volume variation, PAOP, central venous pressure, and LVEDAI did not differ significantly. In the control group, the area under the curve for stroke volume variation was statistically larger than for PAOP, central venous pressure, and LVEDAI.

CONCLUSIONS

Continuous and real-time monitoring of stroke volume variation by pulse contour analysis can predict volume responsiveness and allows real-time assessment of the hemodynamic effect of volume expansion in patients with reduced left ventricular function after cardiac surgery.

Penetration of intravenous hydroxyethyl starch into the cerebrospinal fluid in patients with impaired blood-brain barrier function

Hypovolemic patients with impairment of the blood-brain barrier may receive IV hydroxyethyl starch (HES) to stabilize cardiovascular function and to increase cerebral perfusion pressure. It is not known whether HES can penetrate into the cerebrospinal fluid (CSF) under those conditions. We investigated plasma and CSF levels of HES after IV infusion in patients with suspected disturbance of the blood-brain barrier. Eight adult patients were studied who were being treated for head trauma or subarachnoid hemorrhage, with an external CSF drain in place. All patients exhibited radiographic signs of blood-brain barrier impairment diagnosed by cerebral computed tomography. After IV infusion of 500 to 1000 mL of HES 200,000/0.5, plasma HES levels were measured. Additionally, all CSF that was drained within 8 h after the HES infusion was collected, and HES concentrations were measured. All patients had detectable HES plasma concentrations (3.41 to 9.95 mg/mL). In contrast, no HES could be detected in the CSF of any patient. These data indicate that IV HES 200,000/0.5 does not penetrate into the CSF in patients with disturbed blood-brain barrier function after subarachnoid hemorrhage or head trauma. Further study is required to determine whether HES penetrates into the intracranial interstitium, despite the absence of HES in the CSF.

IMPLICATIONS

Patients may receive IV hydroxyethyl starch (HES) after head trauma or subarachnoid hemorrhage. The results of the present study indicate that in patients with suspected blood-brain barrier impairment, HES does not penetrate from the plasma into the cerebrospinal fluid.

Increased ratio of serum cortisol to cortisone in acute-phase response

BACKGROUND/OBJECTIVES

11beta-Hydroxysteroid dehydrogenase (11beta-HSD) enzymes convert cortisol into inactive cortisone and vice versa. While 11beta-HSD type 2 (mainly localized in the kidney) unidirectionally inactivates cortisol to cortisone, type I isoform (mainly localized in the liver) acts bidirectionally and can thus potentially restore cortisone to active cortisol. The aim of this pilot study was to investigate whether the serum cortisol:cortisone ratio is altered during the acute-phase response, possibly due to altered modulation of 11beta-hydroxysteroid dehydrogenase isoforms.

METHODS

Using liquid chromatography electrospray tandem mass spectrometry, cortisol and cortisone were measured in the serum of hospitalized patients with normal and abnormal CRP concentrations, the latter indicating acute-phase response. Fifteen unselected samples were analyzed, all with a CRP concentration within one of the following ranges to cover a wide range of CRP concentrations evenly: <5, 5-20, 21-50, 51-100, 101-200, and >200 mg/l.

RESULTS

In the heterogeneous study population, increased CRP concentrations significantly correlated with an increased cortisol:cortisone ratio (p < 0.001; r = 0.65, Spearman correlation coefficient). This correlation was independent of increased serum cortisol concentrations found by multivariate regression analysis. The median ratio was 6.4 (interquartile range 5.5-7.4; n = 30) in patients with a CRP concentration < or =20 mg/l, and 11.2 (interquartile range 8.8-13.9; n = 60) in patients with CRP >20 mg/l (p < 0.01).

CONCLUSION

The balance between serum cortisol and cortisone is altered during acute-phase response with a shift towards active cortisol, suggesting that 11beta-HSD isoenzymes play a role in the modulation of systemically available cortisol during acute illness.

The clearance mechanism of chilled blood platelets

Platelet transfusion is a very common lifesaving medical procedure. Not widely known is the fact that platelets, unlike other blood cells, rapidly leave the circulation if refrigerated prior to transfusion. This peculiarity requires blood services to store platelets at room temperature, limiting platelet supplies for clinical needs. Here, we describe the mechanism of this clearance system, a longstanding mystery. Chilling platelets clusters their von Willebrand (vWf) receptors, eliciting recognition of mouse and human platelets by hepatic macrophage complement type 3 (CR3) receptors. CR3-expressing but not CR3-deficient mice exposed to cold rapidly decrease platelet counts. Cooling primes platelets for activation. We propose that platelets are thermosensors, primed at peripheral sites where most injuries occurred throughout evolution. Clearance prevents pathologic thrombosis by primed platelets. Chilled platelets bind vWf and function normally in vitro and ex vivo after transfusion into CR3-deficient mice. Therefore, GPIb modification might permit cold platelet storage.

Trendelenburg positioning after cardiac surgery: effects on intrathoracic blood volume index and cardiac performance

BACKGROUND AND OBJECTIVE

The efficacy of the Trendelenburg position, a common first step to treat suspected hypovolaemia, remains controversial. We evaluated its haemodynamic effects on cardiac preload and performance in patients after cardiac surgery.

METHODS

Twelve patients undergoing mechanical ventilation of the lungs who demonstrated left ventricular 'kissing papillary muscles' by transoesophageal echocardiography, thus suggesting hypovolaemia, were positioned 30 degrees head down for 15 min immediately after cardiac surgery. Cardiac output by thermodilution, central venous pressure, pulmonary artery occlusion pressure, left ventricular end-diastolic area by transoesophageal echocardiography and intrathoracic blood volume by thermo- and dye dilution were determined before, during and after this Trendelenburg manoeuvre.

RESULTS

Trendelenburg's manoeuvre was associated with increases in central venous pressure (9 +/- 2 to 12 +/- 3 mmHg) and pulmonary artery occlusion pressure (8 +/- 2 to 11 +/- 3 mmHg). The intrathoracic blood volume index increased slightly (dye dilution from 836 +/- 129 to 872 +/- 112 mL m(-2); thermodilution from 823 +/- 129 to 850 +/- 131 mL m(-2)) as did the left ventricular end-diastolic area index (7.5 +/- 2.1 to 8.1 +/- 1.7 cm2 m(-2)), whereas mean arterial pressure and the cardiac index did not change significantly. After supine repositioning, the cardiac index decreased significantly below baseline (3.0 +/- 0.6 versus 3.5 +/- 0.8 L min(-1) m(-2)) as did mean arterial pressure (76 +/- 12 versus 85 +/- 11 mmHg), central venous pressure (8 +/- 2 mmHg) and pulmonary artery occlusion pressure (6 +/- 4 mmHg). The intrathoracic blood volume index and left ventricular end-diastolic area index did not differ significantly from baseline.

CONCLUSIONS

Trendelenburg's manoeuvre caused only a slight increase of preload volume, despite marked increases in cardiac-filling pressures, without significantly improving cardiac performance.

Comparison of pulmonary arterial thermodilution and arterial pulse contour analysis: evaluation of a new algorithm

STUDY OBJECTIVE

To compare cardiac index (CI) measurement by arterial pulse contour analysis using two different algorithms (CI(PC), CI(PCnew)) with pulmonary arterial thermodilution values (CI(PA)) so as to evaluate the difference between the conventional algorithm, CI(PC), and a new algorithm, CI(PCnew), that accounts for patients' individual aortic compliance.

DESIGN

Prospective, clinical study.

SETTING

Intensive care unit of a university hospital.

PATIENTS

20 ASA physical status II and III patients following elective cardiac surgery.

MEASUREMENTS AND MAIN RESULTS

360 parallel triplicate determinations of CI (CI(PA), CI(PC), CI(PCnew)) were performed within a 90-minute period during the immediate postoperative period. Prior to the start of the study period, CI(PC) as well as CI(PCnew) were calibrated by triplicate femoral arterial thermodilution measurements. Regression analysis of CI(PA) and CI(PC), as well as CI(PA) and CI(PCnew), revealed r = 0.89, p < 0.001, and r = 0.93, p < 0.001, respectively. Bland-Altman analysis was used for determining the accuracy and precision of CI(PC) and CI(PCnew) compared with CI(PA). The mean differences (m) and standard deviation (SD) between CI(PA) and CI(PC,) as well as CI(PA) and CI(PCnew), resulted in m = -0.312 L/min/m(2), SD = 0.456 L/min/m(2), and m = - 0.140 L/min/m(2), SD = 0.328 L/min/m(2), respectively.

CONCLUSION

Arterial pulse contour analysis measurement of CI using either algorithm correlates well with CI values derived by pulmonary arterial thermodilution. However, the algorithm introduced in this study proved to be a more accurate predictor of values as derived by pulmonary artery catheter.

The effect of remifentanil or fentanyl on postoperative vomiting and pain in children undergoing strabismus surgery

Postoperative vomiting (POV) after strabismus surgery in children results in discomfort and prolonged hospital stays. Opioids increase the incidence of POV. Remifentanil has a context-sensitive half-life of 3 to 4 min, and how this short half-life influences POV in those patients is unknown. We conducted a prospective, double-blinded study in 81 ASA status I or II children from 2 to 12 yr of age undergoing elective strabismus surgery under general anesthesia. Patients were randomized to receive either remifentanil (bolus 1 microg/kg; infusion 0.1-0.2 microg x kg(-1) x min(-1)) or fentanyl (2 microg/kg, and 1 microg/kg every 45 min). POV episodes were recorded for 25 h. Pain scores were obtained by using an objective pain scale for 60 min during recovery. The number of patients who experienced POV did not differ significantly between groups (49% vs 48%). However, in the Remifentanil group, POV episodes were significantly less frequent (0.95 vs 2.2 episodes). In contrast, fentanyl was associated with lower pain scores during the first 30 min of recovery. We conclude that children undergoing strabismus surgery under balanced anesthesia with remifentanil, compared with fentanyl, showed less frequent POV. However, early postoperative analgesia was better with fentanyl.

IMPLICATIONS

Opioids increase the incidence of postoperative vomiting (POV). Remifentanil is characterized by the shortest half-life of all opioids used in anesthetic practice. Therefore, we studied the effect of remifentanil on POV compared with the longer-acting opioid fentanyl in children undergoing strabismus surgery.

Stroke volume variations for assessment of cardiac responsiveness to volume loading in mechanically ventilated patients after cardiac surgery

OBJECTIVE

We hypothesized that measuring stroke volume variation (SVV) during mechanical ventilation by continuous arterial pulse contour analysis allows the accurate prediction and monitoring of changes in cardiac index (CI) in response to volume administration.

DESIGN AND SETTING

Prospective study in an university hospital.

PATIENTS

Twenty mechanically ventilated patients following cardiac surgery.

INTERVENTIONS

Volume loading with oxypolygelatin (3.5%) 20 ml x body mass index over 10 min.

MEASUREMENTS AND RESULTS

SVV, central venous pressure (CVP), pulmonary artery occlusion pressure (PAOP), left ventricular end-diastolic area index (LVEDAI) by transesophageal echocardiography, intrathoracic blood volume index (ITBVI) by transpulmonary thermodilution and CI were determined immediately before and after volume loading. SVV decreased, while CI, CVP, PAOP, ITBVI, and LVEDAI increased significantly. Percentage changes in CI were significantly correlated to percentage changes in SVV (r(2)=-0.59, p<0.001), ITBVI (r(2)=0.79, p<0.001), and PAOP (r(2)=0.33, p<0.05) and to baseline values of SVV (r(2)=0.55, p<0.05) and LVEDAI (r(2)=-0.68, p<0.001).

CONCLUSIONS

SVV may help to determine the preload condition of ventilated patients following cardiac surgery and to predict and continuously monitor effects of volume administered as part of their hemodynamic management.

Intrathoracic blood volume index measured by thermodilution for preload monitoring after cardiac surgery

OBJECTIVE

To investigate the accuracy of measurement of intrathoracic blood volume index by single thermodilution (ITBVI*) and its sensitivity to detect changes in preload after cardiac surgery compared with conventional transpulmonary arterial dye dilution ITBVI and with conventional monitoring (central venous pressure [CVP] and left ventricular end-diastolic area index [EDAI] by transesophageal echocardiography).

DESIGN

Prospective clinical study.

SETTING

University hospital.

PARTICIPANTS

Nineteen patients immediately after cardiac surgery.

INTERVENTIONS

Volume loading was administered with 20 mL of oxypoligelatine (Haemaccel [Behringwerke Aktiengesellschaft Corp, Marburg, Germany]) 3.5% times body mass index over 10 minutes.

MEASUREMENTS AND MAIN RESULTS

Intrathoracic blood volume index was measured by dye dilution (ITBVI) and thermodilution (ITBVI*) immediately before and after volume loading. Measurements of ITBVI and ITBVI* correlated closely (r = 0.94; p < 0.0001). With volume loading, ITBVI and ITBVI* increased significantly from 877 +/- 195 mL/m(2) to 967 +/- 180 mL/m(2) and from 889 +/- 195 mL/m(2) to 954 +/- 185 mL/m(2). Percent changes in ITBVI (deltaITBVI) and ITBVI* (deltaITBVI*) did not differ significantly and correlated closely (r = 0.90; p < 0.0001). Percent changes in cardiac index (CI) as a result of volume loading (deltaCI) revealed significant correlation to deltaITBVI (r = 0.85; p < 0.0001) and to deltaITBVI* (r = 0.76; p < 0.0005). No significant correlation could be found between deltaCI and deltaEDAI or deltaCVP.

CONCLUSION

In patients undergoing cardiac surgery, determination of ITBVI* revealed close agreement with measurements derived by ITBVI. Enhancement in cardiac preload was adequately detected by ITBVI*.

Impact of sepsis, lung injury, and the role of lipid infusion on circulating prostacyclin and thromboxane A(2)

OBJECTIVE

To investigate whether plasma levels of prostacyclin (PGI2) and thromboxane A(2) (TxA2) are a function of the infusion rate of soybean-based fat emulsions, severity of systemic inflammation, and pulmonary organ failure.

DESIGN

Prospective, randomized, crossover study.

SETTING

Intensive care unit of a university hospital.

PATIENTS

Eighteen critically ill patients, ten presenting with severe sepsis, eight with SIRS or sepsis complicated with ARDS.

INTERVENTIONS

Patients were randomly assigned to receive rapid fat infusion over 6 h (rFI) or slow fat infusion over 24 h (sFI) along with parenteral nutrition.

MEASUREMENTS AND RESULTS

The stable prostanoids 6-keto-PGF1alpha and TxB2 were measured in arterial and mixed venous blood samples, and at 6-h periods trans-pulmonary balances (TPB) were calculated. Free linoleic acid fraction was determined in arterial blood. rFI induced greater increase of linoleic acid than sFI in both groups. Enhanced prostanoid levels and correlations with linoleic acid availabilities were found, however, in ARDS patients only, revealing the highest sepsis- and lung injury scores. Averaged TPB per 24 h was positive in the sepsis group and negative in the ARDS group as rFI induced lowest TPB values for TxB2 at 6 h.

CONCLUSION

The quantity of prostanoids formed and their subsequent utilization are dependent on the availability of precursor linoleic acid and are probably affected by the severity of SIRS or sepsis and the existence of pulmonary organ failure, respectively. Because TxA2 might be extracted by the injured lung, rapid infusion of soybean-based fat emulsions should be avoided in patients suffering from severe pulmonary organ failure.

[Transesophageal echocardiography: perioperative evaluation of valvular function]

Since its introduction into the operating room, transesophageal echocardiography (TEE) has proven to be an invaluable diagnostic tool for perioperative patient management. TEE allows direct visualization of structural and functional cardiac abnormalities. Therefore, it has become the most important imaging technique to evaluate valular function. Pressure gradients across a stenotic valve can be calculated by measuring the blood flow velocity within the valve. Additionally, the area of the valve can be estimated by using the continuity equation. The severity of regurgitant blood flow across an incompetent valve can be assessed using color flow, continuous or pulsed-wave Doppler. Surgical patients experience significant changes in blood pressure, intrathoracic pressures and volume status in the perioperative period. Therefore, the interaction between these parameters and valvular function is the focus of recent clinical studies and might in future contribute to the perioperative as well as anesthesiological management of patients with valvular dysfunction.

Optimizing fluid therapy in mechanically ventilated patients after cardiac surgery by on-line monitoring of left ventricular stroke volume variations. Comparison with aortic systolic pressure variations

BACKGROUND

Mechanical ventilation causes changes in left ventricular preload leading to distinct variations in left ventricular stroke volume and systolic arterial pressure. Retrospective off-line quantification of systolic arterial pressure variations (SPV) has been validated as a sensitive method of predicting left ventricular response to volume administration. We report the real-time measurement of left ventricular stroke volume variations (SVV) by continuous arterial pulse contour analysis and compare it with off-line measurements of SPV in patients after cardiac surgery.

METHODS

SVV and SPV were determined before and after volume loading with colloids in 20 mechanically ventilated patients.

RESULTS

SVV and SPV decreased significantly after volume loading and were correlated (r=0.89; P<0.001). Changes in SVV and changes in SPV as a result of volume loading were also significantly correlated (r=0.85; P<0.005). Changes in SVV correlated significantly with changes in stroke volume index (SVI) (r=0.67; P<0.005) as did changes in SPV (r=0.56; P<0.05). SVV determined before volume loading correlated significantly with changes in SVI (R=0.67; P <0.005). Using receiver operating characteristics curves, the area under the curve was statistically greater for SVV (0.824; 95% confidence interval: [CI] 0.64-1.0) and SPV (0.81; CI: 0.62-1.0) than for central venous pressure (0.451; CI: 0.17-0.74).

CONCLUSIONS

Monitoring of SVV enables real-time prediction and monitoring of the left ventricular response to preload enhancement in patients after cardiac surgery and is helpful for guiding volume therapy.