[Artificial intelligence in intensive care medicine]

The integration of artificial intelligence (AI) into intensive care medicine has made considerable progress in recent studies, particularly in the areas of predictive analytics, early detection of complications, and the development of decision support systems. The main challenges remain availability and quality of data, reduction of bias and the need for explainable results from algorithms and models. Methods to explain these systems are essential to increase trust, understanding, and ethical considerations among healthcare professionals and patients. Proper training of healthcare professionals in AI principles, terminology, ethical considerations, and practical application is crucial for the successful use of AI. Careful assessment of the impact of AI on patient autonomy and data protection is essential for its responsible use in intensive care medicine. A balance between ethical and practical considerations must be maintained to ensure patient-centered care while complying with data protection regulations. Synergistic collaboration between clinicians, AI engineers, and regulators is critical to realizing the full potential of AI in intensive care medicine and maximizing its positive impact on patient care. Future research and development efforts should focus on improving AI models for real-time predictions, increasing the accuracy and utility of AI-based closed-loop systems, and overcoming ethical, technical, and regulatory challenges, especially in generative AI systems.

Effects of prone positioning on lung mechanical power components in patients with acute respiratory distress syndrome: a physiologic study

BACKGROUND

Prone positioning (PP) homogenizes ventilation distribution and may limit ventilator-induced lung injury (VILI) in patients with moderate to severe acute respiratory distress syndrome (ARDS). The static and dynamic components of ventilation that may cause VILI have been aggregated in mechanical power, considered a unifying driver of VILI. PP may affect mechanical power components differently due to changes in respiratory mechanics; however, the effects of PP on lung mechanical power components are unclear. This study aimed to compare the following parameters during supine positioning (SP) and PP: lung total elastic power and its components (elastic static power and elastic dynamic power) and these variables normalized to end-expiratory lung volume (EELV).

METHODS

This prospective physiologic study included 55 patients with moderate to severe ARDS. Lung total elastic power and its static and dynamic components were compared during SP and PP using an esophageal pressure-guided ventilation strategy. In SP, the esophageal pressure-guided ventilation strategy was further compared with an oxygenation-guided ventilation strategy defined as baseline SP. The primary endpoint was the effect of PP on lung total elastic power non-normalized and normalized to EELV. Secondary endpoints were the effects of PP and ventilation strategies on lung elastic static and dynamic power components non-normalized and normalized to EELV, respiratory mechanics, gas exchange, and hemodynamic parameters.

RESULTS

Lung total elastic power (median [interquartile range]) was lower during PP compared with SP (6.7 [4.9-10.6] versus 11.0 [6.6-14.8] J/min; P < 0.001) non-normalized and normalized to EELV (3.2 [2.1-5.0] versus 5.3 [3.3-7.5] J/min/L; P < 0.001). Comparing PP with SP, transpulmonary pressures and EELV did not significantly differ despite lower positive end-expiratory pressure and plateau airway pressure, thereby reducing non-normalized and normalized lung elastic static power in PP. PP improved gas exchange, cardiac output, and increased oxygen delivery compared with SP.

CONCLUSIONS

In patients with moderate to severe ARDS, PP reduced lung total elastic and elastic static power compared with SP regardless of EELV normalization because comparable transpulmonary pressures and EELV were achieved at lower airway pressures. This resulted in improved gas exchange, hemodynamics, and oxygen delivery.

TRIAL REGISTRATION

German Clinical Trials Register (DRKS00017449). Registered June 27, 2019. https://drks.de/search/en/trial/DRKS00017449.

Effects of individualised positive end-expiratory pressure titration on respiratory and haemodynamic parameters during the Trendelenburg position with pneumoperitoneum: A randomised crossover physiologic trial

BACKGROUND

The Trendelenburg position with pneumoperitoneum during surgery promotes dorsobasal atelectasis formation, which impairs respiratory mechanics and increases lung stress and strain. Positive end-expiratory pressure (PEEP) can reduce pulmonary inhomogeneities and preserve end-expiratory lung volume (EELV), resulting in decreased inspiratory strain and improved gas-exchange. The optimal intraoperative PEEP strategy is unclear.

OBJECTIVES

To compare the effects of individualised PEEP titration strategies on set PEEP levels and resulting transpulmonary pressures, respiratory mechanics, gas-exchange and haemodynamics during Trendelenburg position with pneumoperitoneum.

DESIGN

Prospective, randomised, crossover single-centre physiologic trial.

SETTING

University hospital.

PATIENTS

Thirty-six patients receiving robot-assisted laparoscopic radical prostatectomy.

INTERVENTIONS

Randomised sequence of three different PEEP strategies: standard PEEP level of 5 cmH 2 O (PEEP 5 ), PEEP titration targeting a minimal driving pressure (PEEP ΔP ) and oesophageal pressure-guided PEEP titration (PEEP Poeso ) targeting an end-expiratory transpulmonary pressure ( PTP ) of 0 cmH 2 O.

MAIN OUTCOME MEASURES

The primary endpoint was the PEEP level when set according to PEEP ΔP and PEEP Poeso compared with PEEP of 5 cmH 2 O. Secondary endpoints were respiratory mechanics, lung volumes, gas-exchange and haemodynamic parameters.

RESULTS

PEEP levels differed between PEEP ΔP , PEEP Poeso and PEEP5 (18.0 [16.0 to 18.0] vs. 20.0 [18.0 to 24.0]vs. 5.0 [5.0 to 5.0] cmH 2 O; P  < 0.001 each). End-expiratory PTP and lung volume were lower in PEEP ΔP compared with PEEP Poeso ( P  = 0.014 and P  < 0.001, respectively), but driving pressure, lung stress, as well as respiratory system and dynamic elastic power were minimised using PEEP ΔP ( P  < 0.001 each). PEEP ΔP and PEEP Poeso improved gas-exchange, but PEEP Poeso resulted in lower cardiac output compared with PEEP 5 and PEEP ΔP .

CONCLUSION

PEEP ΔP ameliorated the effects of Trendelenburg position with pneumoperitoneum during surgery on end-expiratory PTP and lung volume, decreased driving pressure and dynamic elastic power, as well as improved gas-exchange while preserving cardiac output.

TRIAL REGISTRATION

German Clinical Trials Register (DRKS00028559, date of registration 2022/04/27). https://drks.de/search/en/trial/DRKS00028559.

Case Report: Fetoscopic Laparoschisis (FETO-LAP)-A New Therapeutic Route to Explore for Fetuses with Severe Diaphragmatic Hernias

BACKGROUND

The purpose of this report is to describe the seminal case of a near-term human fetus with a life-threatening left diaphragmatic hernia that underwent fetoscopic tracheal occlusion (FETO) combined with fetoscopic partial removal of herniated bowel from the fetal chest by fetoscopic laparoschisis (FETO-LAP).

CASE SUMMARY

A life-threatening left diaphragmatic hernia (liver-up; o/e LHR of ≤25%; MRI lung volume ≤ 20%) was observed in a human fetus at 34 weeks of gestation. After counselling the mother about the high risks of postnatal demise if left untreated, the expected limitations of fetoscopic tracheal occlusion (FETO), and the previously untested option of combining FETO with fetoscopic laparoschisis, i.e., partial removal of the herniated bowel from the fetal chest (FETO-LAP), she consented to the latter novel treatment approach. FETO-LAP was performed at 36 + 5 weeks of gestation under general maternofetal anesthesia. Mother and fetus tolerated the procedure well. The neonate was delivered and the balloon removed on placental support at 37 + 2 weeks of gestation. On ECMO, a rapid increase in tidal volume was seen over the next eight days. Unfortunately, after this period, blood clots obstructed the ECMO circuit and the neonate passed away.

DISCUSSION

This seminal case shows that in a fetus with severe left diaphragmatic hernia, partial removal of the herniated organs from the fetal chest is not only possible by minimally invasive fetoscopic techniques but also well tolerated. As the effect of FETO alone is limited in saving severely affected fetuses, combining FETO with fetoscopic laparoschisis (FETO-LAP) offers a new therapeutic route with multiple, potentially life-saving implications.

Perioperative systemic magnesium sulfate minimizes the incidence of atrial fibrillation after thoracotomy for lung resection: a prospective observational study

Background

Postoperative atrial fibrillation (POAF) is the most common complication following general thoracic surgery. POAF significantly increases the risk of adverse cardiovascular events, such as thromboembolism, heart failure, and mortality. Additionally, it also leads to prolonged hospital stays and higher costs. The objective of this observational study was to examine the impact of perioperative administration of magnesium sulphate (MgSO4) on the incidence of POAF.

Methods

A prospective observational study was conducted, enrolling one hundred patients undergoing thoracotomy for lung resection. We compared the incidence of atrial fibrillation (AF) before and after implementing a change in our standard anesthetic management, which involved the addition of MgSO4. MgSO4 was administered during anesthesia induction at a dose of 40 mg/kg over ten minutes, followed by a 24-hour infusion at a rate of 10 mg/kg/h. The primary outcome was the incidence of POAF within the first seven days after surgery.

Results

Within the initial three days following surgery, there was no significant difference in the cumulative incidence of POAF between the MgSO4 group and the control group. However, on postoperative day 7, patients treated with MgSO4 exhibited a reduced incidence of POAF compared to the control group (4% vs. 26%; P=0.01). In the subgroup of patients not receiving pre-existing β-blockers, the addition of MgSO4 significantly decreased the occurrence of POAF (14% vs. 80%; P<0.001).

Conclusions

Prophylactic administration of MgSO4 is a potentially beneficial approach for reducing the incidence of POAF after non-cardiac surgery, particularly in patients not receiving long-term β-blocker treatment.

Persistent infection with Staphylococcus pseudintermedius in an adult oncology patient with transmission from a family dog

Staphylococcus pseudintermedius is a well known commensal organism of dogs but also a canine opportunistic pathogen. Reports of this organism being recovered from specimens from humans might suggest an increase prevalence in human infections and/or improved diagnostic leading to more accurate identification. Here we report a case of persistent S. pseudintermedius infection in an adult female oncology patient including colonization of the tip of an indwelling catheter. Diligence by laboratories in correctly isolating and identifying this pathogen (including susceptibility testing) is essential for optimal patient care.

Increased mobilization of mesenchymal stem cells in patients with acute respiratory distress syndrome undergoing extracorporeal membrane oxygenation

Background

The acute respiratory distress syndrome (ARDS) is characterized by pulmonary epithelial and endothelial barrier dysfunction and injury. In severe forms of ARDS, extracorporeal membrane oxygenation (ECMO) is often the last option for life support. Endothelial progenitor (EPC) and mesenchymal stem cells (MSC) can regenerate damaged endothelium and thereby improve pulmonary endothelial dysfunction. However, we still lack sufficient knowledge about how ECMO might affect EPC- and MSC-mediated regenerative pathways in ARDS. Therefore, we investigated if ECMO impacts EPC and MSC numbers in ARDS patients.

Methods

Peripheral blood mononuclear cells from ARDS patients undergoing ECMO (n = 16) and without ECMO support (n = 12) and from healthy volunteers (n = 16) were isolated. The number and presence of circulating EPC and MSC was detected by flow cytometry. Serum concentrations of vascular endothelial growth factor (VEGF) and angiopoietin 2 (Ang2) were determined.

Results

In the ECMO group, MSC subpopulations were higher by 71% compared to the non-ECMO group. Numbers of circulating EPC were not significantly altered. During ECMO, VEGF and Ang2 serum levels remained unchanged compared to the non-ECMO group (p = 0.16), but Ang2 serum levels in non-survivors of ARDS were significantly increased by 100% (p = 0.02) compared to survivors.

Conclusions

ECMO support in ARDS is specifically associated with an increased number of circulating MSC, most likely due to enhanced mobilization, but not with a higher numbers of EPC or serum concentrations of VEGF and Ang2.

Corrigendum: Endothelial Progenitor and Mesenchymal Stromal Cells in Newborns With Congenital Diaphragmatic Hernia Undergoing Extracorporeal Membrane Oxygenation

[This corrects the article DOI: 10.3389/fped.2019.00490.].

Impact of different emulsifiers on biocompatibility and inflammatory potential of Perfluorohexyloctane (F6H8) emulsions for new intravenous drug delivery systems

Background

Emulsions on the basis of Perfluorohexyloctane (F6H8), a semifluorinated alkane (SFA), have shown to dissolve and transport highly lipophilic compounds. It is unknown how F6H8-containing emulsions (F6H8-cEM) interact with compartment blood, the reticuloendothelial system (RES), or influence injured organs in vivo. The current study was conducted to investigate the in vitro biocompatibility of F6H8-cEM and their drug delivery properties. Afterward, an in vivo study was performed as a proof-of-concept study in a rat model of acute kidney injury (AKI), which focused on the potential influence of F6H8-cEM on inflammation in an injured organ.

Methods

Two different F6H8-cEM were stabilized by the emulsifying agents Poloxamer 188 (Pluronic^® F68) or lecithin (S75). The two resulting emulsions F6H8-Pluronic or F6H8-lecithin were tested in vitro for the potential modulation of acute inflammation via whole blood assay, FACS, and ELISA. Antioxidant capacity and drug delivery properties were measured with an oxidation assay. Secondly, AKI was induced in the rats, which were treated with the F6H8-lecithin emulsion. Renal function and inflammation were assessed.

Results

Both F6H8-cEM were phagocytized by monocytes and both dose-dependently affected apoptosis (Annexin V binding) in monocytes. TNF-α expression increased dose-dependency for F6H8-Pluronic emulsion but not for F6H8-lecithin in a whole blood assay. Both F6H8-cEM were able to carry α-tocopherol as a model drug. Animals with AKI treated with the F6H8-lecithin emulsion showed a significantly better renal function and less infiltration of inflammatory cells in renal tissue compared to the control, while inflammatory markers in renal tissue, except HO-1, were not affected by F6H8-lecithin.

Conclusions

Pluronic^® F68 does not seem suitable as a biocompatible surfactant for F6H8-cEM. The injured kidney was not negatively influenced by the F6H8-lecithin emulsion. Lecithin-stabilized F6H8-cEM could be tested for preclinical studies as a carrier system for lipophilic agents.

Randomized Trial Based on the Common-Sense Model of Self-regulation to Increase Child Dental Visits

INTRODUCTION

School screening and the note home (pinned to a backpack) informing parents/caregivers that their child needs to see a dentist have not been effective.

OBJECTIVES

The Family Access to a Dentist Study (FADS) evaluated the effectiveness of school interventions based on the common-sense model of self-regulation (CSM) among K-4 children needing restorative treatment.

METHODS

FADS was a multisite double-blind randomized controlled trial with 5 arms. FADS tested a CSM-driven referral letter and dental information guide (DIG) to move caregivers from inaccurate to accurate perceptions of dental caries. Six school districts from Ohio and Washington (14 schools) participated in school years 2015 to 2016 and 2016 to 2017. A total of 611 caregivers were randomized, and 86% (n = 597 children) completed the exit examination. The primary outcome was receipt of care based on a change in oral health status determined clinically within 1 school year.

RESULTS

In accordance with our primary aims, 5 arms were collapsed into 3: CSM letter and reduced CSM letter (combined), CSM letter + DIG and reduced CSM letter + reduced DIG (combined), and standard letter. Among all sites, 39.7% received restorative care (237 of 597). Combined analysis of sites revealed that the CSM referral letter (with and without the DIG) did not increase dental visits when compared with the standard letter. However, for combined sites (East Cleveland, Ohio; Washington), the CSM + DIG increased dental visits when compared with standard letter in univariate analysis (51.3% vs. 40.9%), indicating 1.6-times increased odds of a dental visit (95% CI, 0.97 to 2.58) after imputation and adjustment for covariates. The CSM + DIG group had 1.9-times increased odds (95% CI, 1.21 to 3.08) of care when compared the CSM letter alone.

CONCLUSION

A CSM-driven approach to informing caregivers of the chronic nature of caries with resources in an illustrative manner can increase the benefit of school oral health screening (ClinicalTrials.gov NCT02395120).

KNOWLEDGE TRANSFER STATEMENT

A school dental referral (note home) that tells a parent that the child has cavities has not been effective. In this trial, a referral based on the common-sense model of self-regulation increased follow-up care for children with restorative needs.

Perioperative systemic magnesium sulphate to minimize acute and chronic post-thoracotomy pain: a prospective observational study

Background

Thoracotomy leads to acute and chronic post-thoracotomy pain (CPTP). The purpose of this study was to investigate the effect of magnesium sulphate (MgSO₄) administered perioperatively on acute postoperative and CPTP syndrome.

Methods

One hundred patients were enrolled in this prospective, observational study. Analgesic medication was provided according to the World Health Organization pain relief ladder (control group). The study group received additionally MgSO₄ (40 mg/kg over 10 minutes) during induction of anesthesia followed by an infusion over 24 hours (10 mg/kg/h). The presence and severity of pain were assessed before surgery, on postsurgical days 1-8, 30 and 90, respectively. The Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) was used pre- and postoperatively for documentation of neuropathic pain. The incidence and severity of CPTP were assessed by a telephone survey 30 and 90 days after surgery.

Results

Numerical rating scale (NRS) pain scores at rest were significantly lower in the study group receiving MgSO₄ at days 1 to 8 (P<0.05). Thirty days after surgery, 2.1% of the MgSO₄-patients had a LANSS score ≥12 compared to 14.3% in the control group (P=0.031). No patient had a LANSS score ≥12 in the study group compared to the control group (0% vs. 12.2%, P<0.05) 90 days following surgery.

Conclusions

MgSO₄ administration reduces postoperative pain at rest according to the NRS pain scores and is effective in preventing chronic neuropathic post-thoracotomy pain measured by LANSS score. Prospective-randomized trials are needed to confirm the results of the present study.

Endothelial Progenitor and Mesenchymal Stromal Cells in Newborns With Congenital Diaphragmatic Hernia Undergoing Extracorporeal Membrane Oxygenation

Background: Endothelial progenitor (EPC) and mesenchymal stromal cells (MSC) can regenerate damaged endothelium and thereby improve pulmonary endothelial dysfunction. We do not know, how extracorporeal membrane oxygenation (ECMO) might affect EPC- and MSC-mediated regenerative pathways in patients with congenital diaphragmatic hernia (CDH). Therefore, we investigated, if ECMO support impacts EPC and MSC numbers in CDH patients. Methods: Peripheral blood mononuclear cells from newborns with ECMO-dependent (n = 18) and ECMO-independent CDH (n = 12) and from healthy controls (n = 12) were isolated. The numbers of EPC and MSC were identified by flowcytometry. Serum levels of vascular endothelial growth factor (VEGF) and angiopoietin (Ang)-2 were determined. Results: EPC and MSC were elevated in newborns with CDH. ECMO-dependent infants had higher EPC subpopulation counts (2,1-7,6-fold) before treatment compared to ECMO-independent infants. In the disease course, EPC and MSC subpopulation counts in ECMO-dependent infants were lower than before ECMO initiation. During ECMO, VEGF serum levels were significantly reduced (by 90.5%) and Ang2 levels significantly increased (by 74.8%). Conclusions: Our data suggest that ECMO might be associated with a rather impaired mobilization of EPC and MSC and with a depression of VEGF serum levels in newborns with CDH.

[Extended coronary dissection caused by severe polytrauma with contusio cordis : Venoarterial ECMO-assisted percutaneous coronary intervention]

Treatment of a patient with acute cardiac failure due to a contusio cordis after polytrauma by an interdisciplinary team is reported. Shortly after admission to our shock room, the patient developed cardiogenic shock caused by an extended coronary dissection. After interim cardiopulmonary resuscitation, the patient was stabilized by venoarterial extracorporeal membrane oxygenation (ECMO) and subsequent complex coronary artery intervention in the heart catheter laboratory. Despite the increased left ventricular function which enabled partial weaning from the ECMO, the patient died of multiple organ failure 10 days after admission.

Evaluation of pharmacokinetic properties and anaesthetic effects of propofol in a new perfluorohexyloctane (F6H8) emulsion in rats--A comparative study

Propofol (2,6-diisopropylphenol) is a safe and widely used anaesthetic, but due to low water solubility and high lipophilicity a difficult compound to formulate. The solubility of propofol in the semifluorinated alkane perfluorohexyloctane (F6H8) is very high (>300 mg/ml). In the present work we investigate if a F6H8-based emulsion could be used as a new intravenous drug delivery system for propofol from a pharmacokinetic, pharmacodynamic and safety point of view. The pharmacokinetic parameters were evaluated after an intravenous bolus injection of either Disoprivan(®) or a F6H8-based propofol emulsion in Wistar rats. The onset and end of sedation after multiple dosings (5, 10 and 15 mg/kg bw) were examined. Clinical chemistry and histology were assessed. No significant difference was found for any of the pharmacokinetic parameters. No differences in the onset nor the end of sedation in the tested dosages could be detected. Histology scores revealed no differences. A slightly increased alanine aminotransferase (ALT) was measured after multiple application of the F6H8-propofol emulsion. In conclusion, the F6H8-propofol emulsion showed no significant different pharmacokinetics and sedation properties, compared to a commercial soy-based propofol emulsion. Further, no toxic effects could be detected on the F6H8 emulsion indicating it was a safe excipient in rats.

Bone marrow-derived progenitor cells attenuate inflammation in lipopolysaccharide-induced acute respiratory distress syndrome

Background

Acute respiratory distress syndrome (ARDS) is the most common cause of respiratory failure among critically ill patients. Novel treatment strategies are required to address this common clinical problem. The application of exogenous adult stem cells was associated with a beneficial outcome in various pre-clinical models of ARDS. In the present study we evaluated the functional capacity and homing ability of bone marrow-derived progenitor cells (BMDPC) in vitro and investigated their potential as a treatment strategy in lipopolysaccharide (LPS)-induced ARDS.

Results

Evaluation of the BMDPC showed functional capacity to form endothelial outgrowth cell colonies, which stained positive for CD133 and CD31. Furthermore, DiI-stained BMDPC were demonstrated to home to injured lung tissue. Rats treated with BMDPC showed significantly reduced histopathological changes, a reduced expression of ICAM-1 and VCAM-1 by the lung tissue, an inhibition of proinflammatory cytokine synthesis, a reduced weight loss and a reduced mortality (p < 0.03) compared to rats treated with LPS alone.

Conclusions

These findings suggest that the application of exogenous BMDPC can attenuate inflammation in LPS-induced ARDS and thereby reduce the severity of septic organ damage. Cell therapy strategies using adult stem cells might therefore become a novel and alternative option in ARDS therapy.

Pulsradiolytische Untersuchung von Dimethylthioäther und Dimethylsulfoxyd in wäßriger Lösung

The following absolute rate constants of the reactions of eaq ⊖ and OH with dimethylthioether and dimethylsulfoxide have been determined: k (eaq ⊖ + CH3SCH3) =2.0·107 mol-1 l sec-1; k(e⊖+ CH3SOCH3) =1.7·106; k(OH+CH3SCH3) =5.2·109; k(OH+CH3SOCH3) =4.2·109. The acid and basic components of the equilibrium

are formed in the reactions of OH+CH3SCH3 and eaq ⊖ +CH3SOCH3, respectively. The anion absorbs at 3500 Å. The ρK value of the equilibrium was found to be equal to 10.2. The CH2SCH3 radical (2900 Å) and the ions CH3SCH3 ⊕ or (CH3SCH3)2⊕ (4700 Å) are also formed in the reaction between OH and CH3SCH3. High thioether and low OH⊖ concentrations favour the formation of the positive ion which is believed to result from a reaction between CH3SOHCH3 and CH3SCH3.

[Professional image of anesthetists in the general public. Influence of provision of information and previous experience with the discipline]

BACKGROUND

The profession of the anesthetist in Germany includes the disciplines anesthesia, intensive care, emergency and pain medicine. Despite the versatility and competence of the profession, patients do not appear to have recognized anesthesiology as a medical discipline or anesthetists as medical doctors.

AIM

This study was conducted with the aim of estimating how previous experience and information gathered before contact with the anesthetist for premedication have influenced and changed the perception of patients with regards to the professional fields and the characteristics of anesthetists.

MATERIAL AND METHODS

A total of 3,950 patients from 3 German hospitals were asked to answer a questionnaire handed out by the assistance nurse in the premedication area prior to the medical consultation with the duty anesthetist. The questions involved the patient perception of the discipline, the characteristics of anesthetists and also evaluated the patient previous experience and provision of information. According to the answers 1,753 patients were considered eligible for the study and were categorized into subgroups I-IV (group I interested and experienced with operations, group II interested but inexperienced, group III uninterested but experienced and group IV neither interested nor experienced) for statistical analysis.

RESULTS

Of the respondents 56.2 % had obtained previous information from a general practitioner followed by acquaintances (21.4 %) and the internet (19.9 %), which significantly differed with age. Interested and experienced patients showed the best perception of the profession. Often, the knowledge of interested and uninterested persons did not significantly differ. Interested patients and those with experience of anesthesiology had the best knowledge of anesthesiology. Performing anesthesia was most often identified by all groups (50.9-95.3 %) as a function of anesthetists while the other professional fields were recognized correctly by only 5.8-26.6 %. Depending on the group 41.0-84.4 % regarded anesthetists as medical doctors. Only 15.0-78.3 % of other attributes were associated with anesthetists.

CONCLUSION

Unfortunately, the perception of patients on the versatility and characteristics of anesthetists are poorly developed. However, the knowledge differs significantly depending on previous experience and gathered information. Interestingly patients with previous experience mostly showed better knowledge compared to interested patients. Results suggest that personal interaction, patient-physician communication in general and improved collaboration between general practitioners and anesthetists are the key elements for better patient knowledge, which could lead to increased patient satisfaction.

Abstract 365: Circulating bone marrow-derived VEGFR-2+ progenitor cells in benign and malignant soft tissue tumors

Background : Circulating endothelial progenitor cells (cEPCs) as recruited to the angiogenic vascular system of malignant tumors have been evaluated as a biomarker of tumor remission or progression through therapy in lung and breast cancer. We were interested to analyze the presence of bone marrow derived (BMD) cEPCs in soft tissue malignancies and correlate the changes to treatment efficacy.

Methods: 75 treatment-naïve patients have (41 sarcoma, 21 gastro-intestinal stromal tumors GIST, 12 desmoid) and 11 healthy controls have been enrolled to the study. 25 ml of blood samples were drawn prior to therapy and 4-6 weeks after treatment by 20G iv cannula, collected in tubes containing sodium citrate (0.105 M) and processed within 1 h. Peripheral blood mononuclear cells (PBMC) were isolated by Ficoll density gradient centrifugation and cEPCs were characterized by quadruple staining using antibodies against CD133+, CD34, CD45dim and vascular endothelial growth factor-receptor (VEGF-R)-2+. The expression of cell-surface antigens was determined by four-color immunofluorescence. The frequency of cEPCs in peripheral blood was determined by a 2-dimensional side-scatter/fluorescence dot-plot analysis after exclusion of annexin V-positive cells and appropriate to exclude apoptotic cells. EPC counts are expressed as a percentage of total PBMCs. Serum-concentrations of VEGF and Angiopoetin-2 were determined by ELISA in triplicate samples from 5 ml serum.

Results:The percentage of hematopoietic stem cells (CD34+, CD133+) was significantly increased in sarcoma and desmoid patients (0.44 ± 0.1 %) compared to GIST and healthy controls (0.13 ± 0.04 %; p=0.001). The percentage of VEGFR-2+ cells correspond to cEPC in sarcoma of 0.179 ± 0.190 % vs. healthy controls of 0.025 ± 0.018 %. Values for desmoid patients were similar to sarcoma whereas GIST patients showed values comparable to healthy patients. We found significantly increased mean VEGF levels in both sarcoma and desmoids (359 ± 157 pg/ml) in comparison to healthy controls (27 ± 13 pg/ml; p = 0.001). Ang-2 levels before therapy were significantly lower in healthy controls and desmoids (1665 ± 445 pg/ml) compared to sarcoma and GIST (2929 ± 960 pg/ml, p = 0.033) patients. Patients without signs of tumor recurrence showed normal cEPC values at post-treatment controls, whereas patients with progressive disease had increasing cEPC levels.

Conclusion: This study demonstrates an increased mobilization of cEPCs in sarcoma and (non-metatasizing) desmoids tumors compared to healthy individuals and patients with GIST. cEPCs recruited for vasculogenesis and paracrine effects play a different role in the various subtypes of human soft tissue tumors.

Citation Format: Kai Nowak, Elena Joas, Grietje Beck, Neysan Rafat, Peter Hohenberger. Circulating bone marrow-derived VEGFR-2+ progenitor cells in benign and malignant soft tissue tumors. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 365. doi:10.1158/1538-7445.AM2013-365

Catecholamines reduce dose-dependent oedema formation and inflammatory reaction in an isolated rat lung model

AIM

Since we detected that donor dopamine pre-treatment ameliorates lung function after hypothermia and ischaemia/reperfusion in an isolated rat lung model we studied, whether other catecholamines have beneficial effects on lungs.

MATERIALS AND METHODS

Rats were treated with noradrenaline, adrenaline or dobutamine in different doses. Thereafter lungs were explanted, flushed with Perfadex® solution and stored at 4°C for different time periods. Oedema production was measured and inflammatory mediators were analysed after reperfusion and ventilation.

RESULTS

Low-dose noradrenaline or dobutamine did not reduce tissue oedema after eight hours of hypothermia, whereas higher doses significantly reduced oedema formation. Low-dose catecholamines did not prevent the inflammatory response, whereas higher doses of beta-receptor-stimulating catecholamines significantly blunted inflammatory reaction.

CONCLUSION

This study demonstrates that adrenergic-receptor-stimulating catecholamines have a protective dose-dependent effect on lungs after hypothermia and ischaemia/reperfusion. Although noradrenaline and dobutamine have similar dose-dependent organ-protective effects to dopamine, they have more side-effects.

A randomised controlled trial comparing sugammadex and neostigmine at different depths of neuromuscular blockade in patients undergoing laparoscopic surgery

Deep neuromuscular blockade during certain surgical procedures may improve operating conditions. Sugammadex can be used to reverse deep neuromuscular blockade without waiting for spontaneous recovery. This randomised study compared recovery times from neuromuscular blockade induced by rocuronium 0.6 mg.kg(-1), using sugammadex 4 mg.kg(-1) administered at 1-2 post-tetanic count (deep blockade) or neostigmine 50 μg.kg(-1) (plus atropine 10 μg.kg(-1)) administered at the re-appearance of the second twitch of a train-of-four stimulation (moderate blockade), in patients undergoing laparoscopic surgery. The primary efficacy variable was the time from the start of sugammadex/neostigmine administration to recovery of the train-of-four ratio to 0.9. Patients receiving sugammadex recovered 3.4 times faster than patients receiving neostigmine (geometric mean (95% CI) recovery times of 2.4 (2.1-2.7) and 8.4 (7.2-9.8) min, respectively, p<0.0001). Moreover, 94% (62/66) of sugammadex-treated patients recovered within 5 min, vs 20% (13/65) of neostigmine-treated patients, despite the difference in the depth of neuromuscular blockade at the time of administration of both drugs. The ability to provide deep neuromuscular blockade throughout the procedure but still permit reversal at the end of surgery may enable improved surgical access and an enhanced visual field.

Aerosolized semifluorinated alkanes as excipients are suitable for inhalative drug delivery--a pilot study

Semifluorinated alkanes (SFAs) have been described as potential excipients for pulmonary drug delivery, but proof of their efficacy is still lacking. We tested whether SFA formulations with the test drug ibuprofen can be nebulised and evaluated their pharmacokinetics. Physico-chemical properties of five different ibuprofen formulations were evaluated: an aqueous solution (H2O), two different SFAs (perfluorohexyloctane (F6H8), perfluorobutylpentane (F4H5)) with and without ethanol (SFA/EtOH). Nebulisation was performed with a jet catheter system. Inhalative characteristics were evaluated by laser diffraction. A confirmative animal study with an inhalative single-dose (6 mg/kg) of ibuprofen with each formulation was performed in anaesthetised healthy rabbits. Plasma samples at defined time points and lung tissue harvested after the 6-h study period were analyzed by HPLC-MS/MS. Pharmacokinetics were calculated using a non-compartment model. All formulations were nebulisable. No differences in aerodynamic diameters (MMAD) were detected between SFA and SFA/EtOH. The ibuprofen plasma concentration-time curve (AUC) was highest with F4H5/EtOH. In contrast, F6H8/EtOH had the highest deposition of ibuprofen into lung tissue but the lowest AUC. All tested SFA and SFA/EtOH formulations are suitable for inhalation. F4H5/EtOH formulations might be used for rapid systemic availability of drugs. F6H8/EtOH showed intrapulmonary deposition of the test drug.

Semifluorinated alkanes--a new class of excipients suitable for pulmonary drug delivery

INTRODUCTION

Semifluorinated alkanes (SFAs) are considered as diblock molecules with fluorocarbon and hydrocarbon segments. Unlike Perfluorocarbons (PFCs), SFAs have the potential to dissolve several lipophilic or water-insoluble substances. This makes them possibly suitable as new excipients for inhalative liquid drug carrier systems.

PURPOSE

The aim of the study was to compare physico-chemical properties of different SFAs and then to test their respective effects in healthy rabbit lungs after nebulisation.

METHODS

Physico-chemical properties of four different SFAs, i.e. Perfluorobutylpentane (F4H5), Perfluorohexylhexane (F6H6), Perfluorohexyloctane (F6H8) and Perfluorohexyldodecane (F6H12) were measured. Based on these results, aerosol characteristics of two potential candidates suitable as excipients for pulmonary drug delivery, i.e. F6H8 and F4H5, were determined by laser light diffraction. Tracheotomised and ventilated New Zealand White rabbits were nebulised with either a high- or a low dose of SFAs (F6H8(low/high) and F4H5(low/high)) or saline (NaCl). Ventilated healthy animals served as controls (Sham). Arterial blood gases, lung mechanics, heart rate and blood pressure were recorded prior to nebulisation and in 30 min intervals during the 6-h study period.

RESULTS

Out of the four SFAs studied initially, no satisfactory behaviour as a solvent has to be expected because of low lipophilicity for F6H6. Output rate during aerosolisation was very low for F6H12. F6H8 and F4H5 presented comparable aerosolisation characteristics and lipophilicity and were therefore tested in the in vivo model. Aerosol therapy, either SFAs or saline, impaired paO2/FiO2 ratio, dynamic lung compliance and respiratory mechanics in all groups, except for F4H5(low) group which behaved like the control group (Sham). F4H5(low) had no adverse effects on gas exchange or pulmonary mechanics.

CONCLUSIONS

Perfluorobutylpentane (F4H5) in a low-dose application may be suitable as a new inhalable excipient in SFA-based pulmonary drug delivery systems for lipophilic or water-insoluble substances.

Modulation of brain dead induced inflammation by vagus nerve stimulation

Because the vagus nerve is implicated in control of inflammation, we investigated if brain death (BD) causes impairment of the parasympathetic nervous system, thereby contributing to inflammation. BD was induced in rats. Anaesthetised ventilated rats (NBD) served as control. Heart rate variability (HRV) was assessed by ECG. The vagus nerve was electrically stimulated (BD + STIM) during BD. Intestine, kidney, heart and liver were recovered after 6 hours. Affymetrix chip-analysis was performed on intestinal RNA. Quantitative PCR was performed on all organs. Serum was collected to assess TNFalpha concentrations. Renal transplantations were performed to address the influence of vagus nerve stimulation on graft outcome. HRV was significantly lower in BD animals. Vagus nerve stimulation inhibited the increase in serum TNFalpha concentrations and resulted in down-regulation of a multiplicity of pro-inflammatory genes in intestinal tissue. In renal tissue vagal stimulation significantly decreased the expression of E-selectin, IL1beta and ITGA6. Renal function was significantly better in recipients that received a graft from a BD + STIM donor. Our study demonstrates impairment of the parasympathetic nervous system during BD and inhibition of serum TNFalpha through vagal stimulation. Vagus nerve stimulation variably affected gene expression in donor organs and improved renal function in recipients.

Modulation of brain dead induced inflammation by vagus nerve stimulation

Because the vagus nerve is implicated in control of inflammation, we investigated if brain death (BD) causes impairment of the parasympathetic nervous system, thereby contributing to inflammation. BD was induced in rats. Anaesthetised ventilated rats (NBD) served as control. Heart rate variability (HRV) was assessed by ECG. The vagus nerve was electrically stimulated (BD + STIM) during BD. Intestine, kidney, heart and liver were recovered after 6 hours. Affymetrix chip-analysis was performed on intestinal RNA. Quantitative PCR was performed on all organs. Serum was collected to assess TNFalpha concentrations. Renal transplantations were performed to address the influence of vagus nerve stimulation on graft outcome. HRV was significantly lower in BD animals. Vagus nerve stimulation inhibited the increase in serum TNFalpha concentrations and resulted in down-regulation of a multiplicity of pro-inflammatory genes in intestinal tissue. In renal tissue vagal stimulation significantly decreased the expression of E-selectin, IL1beta and ITGA6. Renal function was significantly better in recipients that received a graft from a BD + STIM donor. Our study demonstrates impairment of the parasympathetic nervous system during BD and inhibition of serum TNFalpha through vagal stimulation. Vagus nerve stimulation variably affected gene expression in donor organs and improved renal function in recipients.

Pre-ischaemic conditioning of the pulmonary endothelium by immunotargeting of catalase via angiotensin-converting-enzyme antibodies

BACKGROUND

Alleviation of oxidative stress via targeted delivery of catalase to the pulmonary endothelium by conjugation of angiotensin-converting-enzyme (ACE) monoclonal antibodies attenuates lung injury in an in vivo model of warm lung ischaemia and reperfusion. This study evaluates treatment of lung allografts with conjugates of anti-ACE antibody with catalase (9B9-CAT) in the setting of hypothermic preservation and reports the effect on ischaemia/reperfusion injury in this model.

METHODS

Rats were injected 1h prior to lung harvesting with mouse immunoglobulin G (IgG) (negative controls), catalase only (CAT) or anti-ACE mAb 9B9 conjugated with catalase (9B9-CAT). Lungs were flushed with low-potassium dextran (LPD) solution, excised and stored at 4 degrees C for 4 and 8h. Grafts were isolated and directly reperfused at 37 degrees C for up to 180 min. Peak inspiratory pressure (PIP), pulmonary arterial pressure (PAP) and lung weight were measured during reperfusion. Anti-oxidative capacity and catalase activity were measured in frozen lung tissue and inflammatory parameters were detected during reperfusion in perfusate solution.

RESULTS

Cold ischaemia of 8h significantly increased lung weight gain, PIP and PAP in non-immune mouse IgG and CAT-treated lungs than in 9B9-CAT-treated lungs (p<0.005). Significantly higher catalase activity and anti-oxidative status were found in the lung tissue of animals conditioned with 9B9-CAT after 4 and 8h of cold storage than in animals treated with catalase (CAT) alone or in animals treated with non-immune mouse IgG (p<0.01).

CONCLUSION

These results validate immunotargeting by anti-ACE mAb conjugated with catalase as a prospective and specific strategy to augment anti-oxidative defence of the pulmonary endothelium during lung transplantation. Vascular immunotargeting of anti-oxidative enzymes could limit reactive oxygen species mediated ischaemia-reperfusion (I/R) injury of the lung and has the potential to become a promising modality for extension of the viability of banked transplantation tissue.

[Special anaesthesiological requirements in bariatric surgery]

Obesity is a growing healthcare problem in all industrial countries, which occurs with increasing frequency in young people and indicates bariatric surgery. Obesity increases the risk for pulmonary and cardiovasculary side effects and also the anaesthesiologist is confronted with significantly more problems when the patient is overweight and obese. The present review focuses on the surgical techniques and the anaesthetic implications of bariatric surgery.

The carbon monoxide releasing molecule (CORM-3) inhibits expression of vascular cell adhesion molecule-1 and E-selectin independently of haem oxygenase-1 expression

BACKGROUND AND PURPOSE

Although carbon monoxide (CO) can modulate inflammatory processes, the influence of CO on adhesion molecules is less clear. This might be due to the limited amount of CO generated by haem degradation. We therefore tested the ability of a CO releasing molecule (CORM-3), used in supra-physiological concentrations, to modulate the expression of vascular cell adhesion molecule (VCAM)-1 and E-selectin on endothelial cells and the mechanism(s) involved.

EXPERIMENTAL APPROACH

Human umbilical vein endothelial cells (HUVECs) were stimulated with tumour necrosis factor (TNF)-alpha in the presence or absence of CORM-3. The influence of CORM-3 on VCAM-1 and E-selectin expression and the nuclear factor (NF)-kappaB pathway was assessed by flow cytometry, Western blotting and electrophoretic mobility shift assay.

KEY RESULTS

CORM-3 inhibited the expression of VCAM-1 and E-selectin on TNF-alpha-stimulated HUVEC. VCAM-1 expression was also inhibited when CORM-3 was added 24 h after TNF-alpha stimulation or when TNF-alpha was removed. This was paralleled by deactivation of NF-kappaB and a reduction in VCAM-1 mRNA. Although TNF-alpha removal was more effective in this regard, VCAM-1 protein was down-regulated more rapidly when CORM-3 was added. CORM-3 induced haem oxygenase-1 (HO-1) in a dose- and time-dependent manner, mediated by the transcription factor, Nrf2. CORM-3 was still able to down-regulate VCAM-1 expression in HUVEC transfected with siRNA for HO-1 or Nrf2.

CONCLUSIONS AND IMPLICATIONS

Down-regulation of VCAM and E-selectin expression induced by CORM-3 was independent of HO-1 up-regulation and was predominantly due to inhibition of sustained NF-kappaB activation.

'Fast-track' colonic surgery in Austria and Germany--results from the survey on patterns in current perioperative practice

OBJECTIVE

'Fast-track' rehabilitation has been shown to accelerate recovery, reduce general morbidity and decrease hospital stay after elective colonic surgery. Despite this evidence, there is no information on the acceptance and utilization of these concepts among the entirety of Austrian and German surgeons.

METHOD

In 2006, a questionnaire concerning perioperative routines in elective, open colonic resection was sent to the chief surgeons of 1270 German and 120 Austrian surgical centres.

RESULTS

The response rate was 63% in Austria (76 centres) and 30% in Germany (385 centres). Mechanical bowel preparation is used by the majority (Austria, 91%; Germany, 94%); the vertical incision is the standard method of approach to the abdomen in Austria (79%) and Germany (83%), nasogastric decompression tubes are rarely used, one-third of the questioned surgeons in both countries use intra-abdominal drains. Half of the surgical centres allow the intake of clear fluids on the day of surgery and one-fifth offer solid food on that day. Epidural analgesia is used in three-fourths of the institutions.

CONCLUSION

Although there is an evident benefit of fast-track management, the survey shows that they are not yet widely used as a routine in Austria and Germany.

High mobility group box 1 and adenosine are both released by endothelial cells during hypothermic preservation

Hypothermic preservation of solid allografts causes profound damage of vascular endothelial cells. This, in turn, might activate innate immunity. In the present study we employed an in vitro model to study to what extent supernatants of damaged endothelial cells are able to activate innate immunity and to study the nature of these signals. The expression of high mobility group box 1 (HMGB1) and adhesion molecules on human umbilical vein endothelial cell was studied by immunofluorescence, fluorescence activated cell sorter and Western blotting. Cytokine production was performed by enzyme-linked immunosorbent assay. HMGB1 expression was lost completely in endothelial cells after hypothermic preservation. This was associated with cell damage as it occurred only in untreated endothelial cell but not in cells rendered resistant to hypothermia-mediated damage by dopamine treatment. Only supernatants from hypothermia susceptible cells up-regulated the expression of interleukin (IL)-8 and adhesion molecules in cultured endothelial cells in an HMGB1-dependent manner. In whole blood assays, both supernatants of hypothermia susceptible and resistant cells inhibited tumour necrosis factor (TNF)-alpha production concomitantly with an increased IL-10 secretion. The activity of the supernatants was already found after 6 h of hypothermic preservation, and paralleled the decrease in intracellular adenosine triphosphate (ATP) levels. Modulation of TNF-alpha and IL-10 production by these supernatants was abrogated completely by prior treatment with adenosine deaminase and was similar to the response of an A2R agonist. Our study demonstrates that both HMGB1 and adenosine are released during hypothermic preservation. While release of HMGB1 is caused by cell damage, release of adenosine seems to be related to ATP hydrolysis, occurring in both susceptible and resistant cells.