Prognostic significance of early acute kidney injury in COVID-19 patients requiring mechanical ventilation: a single-center retrospective analysis

Acute kidney injury (AKI) is associated with impaired outcomes in critically ill COVID-19 patients. However, the prognostic significance of early AKI is poorly described. We aimed to determine whether AKI on admission to the intensive care unit (ICU) and its development within the first 48 h predict the need for renal replacement therapy (RRT) and increased mortality. An analysis of 372 patients with COVID-19 pneumonia requiring mechanical ventilation without advanced chronic kidney disease from 2020 to 2021 was performed. The AKI stages on ICU admission and Day 2 were determined using adapted KDIGO criteria. The early development of renal function was assessed by the change in AKI score and the Day-2/Day-0 creatinine ratio. Data were compared between three consecutive COVID-19 waves and with data before the pandemic. Both ICU and 90-day mortality (79% and 93% vs. 35% and 44%) and the need for RRT increased markedly with advanced AKI stage on ICU admission. Similarly, an early increase in AKI stage and creatinine implied highly increased mortality. RRT was associated with very high ICU and 90-day mortality (72% and 85%), even surpassing that of patients on ECMO. No difference was found between consecutive COVID-19 waves, except for a lower mortality in the patients on RRT in the last omicron wave. Mortality and need for RRT were comparable in the COVID-19 and pre-COVID-19 patients, except that RRT did not increase ICU mortality in the pre-COVID-19 era. In conclusion, we confirmed the prognostic significance of both AKI on ICU admission and its early development in patients with severe COVID-19 pneumonia.

Hyperoxemia post thoracic surgery - Does it matter?

Introduction

Post-operative oxygen therapy is used to prevent hypoxemia and surgical site infection. However, with improvements of anesthesia techniques, post-operative hypoxemia incidence is declining and the benefits of oxygen on surgical site infection have been questioned. Moreover, hyperoxemia might have adverse effects on the pulmonary and cardiovascular systems. We hypothesized hyperoxemia post thoracic surgery is associated with post-operative pulmonary and cardiovascular complications.

Methods

Consecutive lung resection patients were included in this post-hoc analysis. Post-operative pulmonary and cardiovascular complications were prospectively assessed during the first 30 post-operative days, or hospital stay. Arterial blood gases were analyzed at 1, 6 and 12 h after surgery. Hyperoxemia was defined as arterial partial pressure of oxygen (PaO₂)>100 mmHg. Patients with hyperoxemia duration in at least two adjacent time points were considered as hyperoxemic. Student t-test, Mann-Whitney U test and two-tailed Fisher exact test were used for group comparison. P values < 0.05 were considered statistically significant.

Results

Three hundred sixty-three consecutive patients were included in this post-hoc analysis. Two hundred five patients (57%), were considered hyperoxemic and included in the hyperoxemia group. Patients in the hyperoxemia group had significantly higher PaO₂ at 1, 6 and 12 h after surgery (p < 0.05). Otherwise, there was no significant difference in age, sex, comorbidities, pulmonary function tests parameters, lung surgery procedure, incidence of post-operative pulmonary and cardiovascular complications, intensive care unit and hospital length of stay and 30-day mortality.

Conclusion

Hyperoxemia after lung resection surgery is common and not associated with post-operative complications or 30-day mortality.

Empagliflozin-associated postoperative mixed metabolic acidosis. Case report and review of pathogenesis

BACKGROUND

Euglycemic diabetic ketoacidosis associated with SGLT2 inhibitors is a rare, relatively new and potentially fatal clinical entity, characterized by metabolic acidosis with normal or only moderately elevated glycemia. The mechanisms are not fully understood but involve increased ketogenesis and complex renal metabolic dysfunction, resulting in both ketoacidosis and hyperchloremic acidosis. We report a rare case of fatal empagliflozin-associated acidosis with profound hyperchloremia and review its pathogenesis.

CASE PRESENTATION

A patient with type 2 diabetes mellitus treated with empagliflozin underwent an elective hip replacement surgery. Since day 4 after surgery, he felt generally unwell, leading to cardiac arrest on the day 5. Empagliflozin-associated euglycemic diabetic ketoacidosis with severe hyperchloremic acidosis was identified as the cause of the cardiac arrest.

CONCLUSIONS

This unique case documents the possibility of severe SGLT2 inhibitor-associated mixed metabolic acidosis with a predominant hyperchloremic component. Awareness of this possibility and a high index of suspicion are crucial for correct and early diagnosis.

The risk of post-operative pulmonary complications in lung resection candidates with normal forced expiratory volume in 1 s and diffusing capacity of the lung for carbon monoxide: a prospective multicentre study

Introduction

According to the guidelines for preoperative assessment of lung resection candidates, patients with normal forced expiratory volume in 1 s (FEV₁) and diffusing capacity of the lung for carbon monoxide (D _LCO) are at low risk for post-operative pulmonary complications (PPC). However, PPC affect hospital length of stay and related healthcare costs. We aimed to assess risk of PPC for lung resection candidates with normal FEV₁ and D _LCO (>80% predicted) and identify factors associated with PPC.

Methods

398 patients were prospectively studied at two centres between 2017 and 2021. PPC were recorded from the first 30 post-operative days. Subgroups of patients with and without PPC were compared and factors with significant difference were analysed by uni- and multivariate logistic regression.

Results

188 subjects had normal FEV₁ and D _LCO. Of these, 17 patients (9%) developed PPC. Patients with PPC had significantly lower pressure of end-tidal carbon dioxide (P _ETCO2 ) at rest (27.7 versus 29.9; p=0.033) and higher ventilatory efficiency (V'_E/V'_CO2 ) slope (31.1 versus 28; p=0.016) compared to those without PPC. Multivariate models showed association between resting P _ETCO2 (OR 0.872; p=0.035) and V'_E/V'_CO2 slope (OR 1.116; p=0.03) and PPC. In both models, thoracotomy was strongly associated with PPC (OR 6.419; p=0.005 and OR 5.884; p=0.007, respectively). Peak oxygen consumption failed to predict PPC (p=0.917).

Conclusions

Resting P _ETCO2 adds incremental information for risk prediction of PPC in patients with normal FEV₁ and D _LCO. We propose resting P _ETCO2 be an additional parameter to FEV₁ and D _LCO for preoperative risk stratification.

Prediction of Postoperative Complications: Ventilatory Efficiency and Rest End-tidal Carbon Dioxide

BACKGROUND

Cardiopulmonary exercise testing parameters including ventilatory efficiency (V_E/VCO₂ slope) are used for risk assessment of lung resection candidates. However, many patients are unable or unwilling to undergo exercise. V_E/VCO₂ slope is closely related to the partial pressure of end-tidal carbon dioxide (P_ETCO₂). We hypothesized P_ETCO₂ at rest predicts postoperative pulmonary complications.

METHODS

Consecutive lung resection candidates were included in this prospective multicenter study. Postoperative respiratory complications were assessed from the first 30 postoperative days or from the hospital stay. Student t test or Mann-Whitney U test was used for comparison. Multivariate stepwise logistic regression analysis was used to analyze association with the development of postoperative pulmonary complications. The De Long test was used to compare area under the curve (AUC). Data are summarized as median (interquartile range).

RESULTS

Three hundred fifty-three patients were analyzed, of which 59 (17%) developed postoperative pulmonary complications. P_ETCO₂ at rest was significantly lower (27 [24-30] vs 29 [26-32] mm Hg; P < .01) and V_E/VCO₂ slope during exercise significantly higher (35 [30-40] vs 29 [25-33]; P < .01) in patients who developed postoperative pulmonary complications. Both rest P_ETCO₂ with odds ratio 0.90 (95% confidence interval [CI] 0.83-0.97); P = .01 and V_E/VCO₂ slope with odds ratio 1.10 (95% CI 1.05-1.16); P < .01 were independently associated with postoperative pulmonary complications by multivariate stepwise logistic regression analysis. There was no significant difference between AUC of both models (rest P_ETCO₂: AUC = 0.79 (95% CI 0.74-0.85); V_E/VCO₂ slope: AUC = 0.81 (95% CI 0.75-0.86); P = .48).

CONCLUSIONS

P_ETCO₂ at rest has similar prognostic utility as V_E/VCO₂ slope, suggesting rest P_ETCO₂ may be used for postoperative pulmonary complications prediction in lung resection candidates.

A phase I, open-label study evaluating the safety and pharmacokinetics of trifluridine/tipiracil in patients with advanced solid tumors and varying degrees of renal impairment

PURPOSE

Trifluridine/tipiracil (FTD/TPI) is approved for advanced colorectal and gastric/gastroesophageal cancer; however, data in patients with renal impairment (RI) are limited. This phase I study evaluated FTD/TPI in patients with advanced solid tumors and varying degrees of RI to develop dosing guidance.

METHODS

Patients were enrolled into normal renal function (CrCl ≥ 90 mL/min), mild RI (CrCl 60-89 mL/min), or moderate RI (CrCl 30-59 mL/min) cohorts and administered the recommended FTD/TPI dose (35 mg/m² twice daily, days 1-5 and 8-12; 28-day cycle). Based on interim pharmacokinetics/safety data, patients with severe RI (CrCl 15-29 mL/min) were enrolled and received FTD/TPI 20 mg/m² twice daily.

RESULTS

Forty-three patients (normal renal function [n = 12]; mild RI [n = 12]; moderate RI [n = 11]; severe RI [n = 8]) were enrolled and treated. At steady state, compared to values in patients with normal renal function, FTD area under the curve (AUC) was not significantly different in patients with RI, but TPI AUC was significantly higher and increased with RI severity. FTD/TPI safety profile was consistent with prior experience, but grade ≥ 3 adverse events (AEs) were more frequent in the RI cohorts (83.3% [mild], 90.9% [moderate], 75.0% [severe], and normal [50.0%]). Hematologic AEs (anemia and neutropenia) were more frequent with RI. Overall, seven patients discontinued because of unrelated, nonhematologic AEs.

CONCLUSION

FTD/TPI is safe and tolerable at the recommended 35 mg/m² dose in patients with mild/moderate RI and at the reduced 20 mg/m² dose in patients with severe RI.

TRIAL REGISTRATION

NCT02301117, registration date: November 21, 2014.

Interpretive discrepancies caused by target values inter-batch variations in chemiluminescence immunoassay for SARS-CoV-2 IgM/IgG by MAGLUMI

Plasma specimens from coronavirus disease 2019 patients were double-tested for anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies by two different batches of MAGLUMI 2019-nCov immunoglobulin M/immunoglobulin G (IgM/IgG) assays to evaluate IgM/IgG levels, qualitative interpretation, antibody kinetics, and linearity of diluted specimen. Here we show that (i) high-level IgM specimens need to be diluted with negative human plasma but not kit diluents and (ii) measured anti-SARS-CoV-2 IgM/IgG concentrations are substantially higher with later marketed immunoassay batch leading to (iii) the change of qualitative interpretation (positive vs. negative) in 12.3% of specimens measured for IgM, (iv) the informative time-course pattern of antibody production only when data from different immunoassay batches are not combined.

Pharmacokinetic Comparison of Subcutaneous and Intravenous Nadroparin Administration for Thromboprophylaxis in Critically Ill Patients on Vasopressors

INTRODUCTION

Critically ill patients are exposed to a high risk of developing thromboembolism. Moreover, standard prophylaxis with subcutaneous (SC) heparin is less efficient in patients requiring vasopressors. The aim is a comparison of pharmacokinetics between SC and intravenous (IV) applied nadroparin.

METHODS

Thirty-eight ventilated ICU patients requiring vasopressor support were randomized into a single dose of nadroparin 3,800 IU (0.4 mL) subcutaneously (SC group) or 1,900 IU (0.2 mL) intravenously (IV group). Anti-factor Xa activity (anti-Xa) was observed over 24 h; data are stated as median (IQR).

RESULTS

Peak anti-Xa was significantly higher in the IV group 0.42 (0.39-0.43) IU/mL than in the SC group 0.16 (0.09-0.18) IU/mL (p < 0.001). There was a trend towards higher area under the curve (AUC) of anti-Xa in the SC group 1.41 (0.41-1.80) IU/mL × h than in the IV group 1.04 (0.93-1.13) IU/mL × h (p = 0.08). In the SC group, there was a negative correlation between anti-Xa AUC and both capillary refill time Xa (r = -0.86) and norepinephrine dose (r = -0.68). In the IV group, anti-Xa decrease half-life was 1.6 (1.4-2.0) h.

CONCLUSIONS

IV administration of 1,900 IU of nadroparin led to a predictable effective peak anti-Xa. After SC administration, anti-Xa was heterogeneous and significantly influenced by peripheral perfusion.

Comparison of Active Substance Losses and Total Weight Losses of Tablets Administered Via Feeding Tube

BACKGROUND/AIMS

Administration of tablets via feeding tube (FT) is often associated with significant drug losses, as was confirmed by weighing. The aim of this study was to measure the proportion of active substance losses (ASLs) in an in vitro model.

METHODS

A film-coated tablet (FilmCT) containing clopidogrel (Trombex®) and a tablet with enteric coating (EntericCT) containing pantoprazole (Controloc®) were crushed in a mortar and transferred by method A (tablet powder was transferred into the beaker, poured into the syringe and water added) and method B (water was added into the mortar, suspension drawn into the syringe) and administered via FT in an in vitro model. Total losses were measured with analytical balance and, simultaneously, ASL were analyzed with high-performance liquid chromatography UV-detection (HPLC-UV).

RESULTS

ASL was different to weighing only in the case of EntericCT prepared by method B (2.0 ± 4.2 and 10.7 ± 0.8% for HPLC-UV and weighing, respectively; p = 0.004). HPLC-UV confirmed significantly lower ASL when method B was used for either EntericCT (34.3 ± 7.2 vs. 2.0 ± 4.2%; p < 0.001) or FilmCT (14.1 ± 2.2 vs. 7.7 ± 4.1%; p < 0.01).

CONCLUSION

Drug loss analysis with analytical balance may overestimate ASL, as was proved for EntericCT in this study. ASL were significantly lower when method B was used.

Circadian leptin concentration changes in critically ill heart failure patients

Physiologically, leptin concentration is controlled by circadian rhythm. However, in critically ill patients, circadian rhythm is disrupted. Thus we hypothesized that circadian leptin concentration changes are not preserved in critically ill patients. Ten consecutive critically ill heart failure patients with the clinical indication for mechanical ventilation and sedation were included into our study. Plasma leptin concentration was measured every 4 h during the first day (0-24 h) and during the third day (48-72 h) after admission. During the first day, there were significant leptin concentration changes (ANOVA, p<0.05), characterized by an increase in concentration by 44 % (16-58 %); p=0.02 around noon (10 am-2 pm) and then a decrease in concentration by 7 % (1-27 %); p=0.04 in the morning (2 am-6 am). In contrast, there was no significant change in leptin concentration during the third day after admission (ANOVA, p=0.79). Based on our preliminary results, we concluded that in critically ill heart failure patients, the circadian rhythm of plasma leptin concentration seems to be preserved during the first but not during the third day after admission.

Effects of Carrier Solution on Insulin Bioavailability

BACKGROUND

The aim of our study is to assess the influence of the base solution on the availability of biologic insulin expressed in the value of total insulin using the radioimmunoassay method and to monitor the influence of the base solution on the total insulin concentration over time.

METHODS

Total insulin in a saline and in a total nutrient admixture was measured using the RIA method. In 15 experiments, the application of the saline by a perfusor (8 IU Actrapid HM, 100 IU/1 mL + 20 mL saline) was carried out at time intervals of baseline, 5, 10, 30, 60, 90, and 210 minutes. The application of the total nutrient admixture (8 IU Actrapid HM + 20 mL total nutrient admixture) was carried out in the same way. The MANOVA, ANOVA and paired t test with Bonferroni correction were then used for statistical evaluation.

RESULTS

The average values of insulin concentration in saline at given time intervals were 21.5 +/- 11.3 mIU/L (5.4% of the theoretically calculated concentration). The level of insulin in the total nutrient admixture did not change over time, and it reached the values of 115.2 +/- 22.3 (28.8% of the theoretically calculated concentration). Changes in insulin concentration in time were found only in the saline (ANOVA time effect p < .001 for saline; p = .26 for total nutrient admixture).

CONCLUSIONS

The availability of insulin was significantly higher in the total nutrient admixture solution than in the saline in the 3.5-hour experiment. The dependence of insulin concentration on time is present only in saline, and the main changes in insulin bioavailability are within first 60 minutes. The difference could be caused by smaller insulin absorption to the syringe walls and to the set, owing to the amino acids in the mixture. The question whether the amino acid concentration affects insulin bioavailability stays opened to other studies.

Glycemia Influences on Glucose Metabolism in Sepsis During Hyperinsulinemic Clamp

BACKGROUND

We investigated glucose metabolism in septic patients during hyperglycemic clamps and compared the different levels of insulinemia and glycemia.

METHODS

In 10 non-diabetic stable septic patients on mechanical ventilation with baseline glycemia >6 mmol/L and continuous insulin infusion, 3 steps of hyperinsulinemic clamp were performed after 8 hours without caloric intake. In step 1, the targets were insulinemia of 250 mIU/L and glycemia of 5 mmol/L; in step 2, insulinemia of 250 mIU/L and glycemia of 10 mmol/L; in step 3, insulinemia of 1250 mIU/L and glycemia of 5 mmol/L. Glucose uptake was calculated as the amount of glucose per time needed to maintain the target level of glycemia. Glucose oxidation was calculated from indirect calorimetry and urinary nitrogen losses. Values are provided as means +/- SD. A two-way analysis of variance and Scheffe's method were used for statistical analysis and p < .05 was considered significant.

RESULTS

At step 1, glucose uptake was lower than at step 2 (3.8 +/- 2.48 mg/kg/min and 7.9 +/- 3.45 mg/kg/min, respectively; p < .001). Glucose oxidation was also lower at step 1 (2.6 +/- 0.98 and 4.2 +/- 1.85 mg/kg/min, respectively; p < .01). Glucose storage was low at step 1 (0.7 +/- 1.39) and increased at step 2 (3.5 +/- 2.18; p < .05). In step 3, glucose uptake was 7.0 +/- 2.1, oxidation was 3.6 +/- 1.37, and storage was 2.9 +/- 2.79. There was no significant difference in all these parameters between steps 2 and 3. Energy expenditure between steps 1, 2 and 3 did not change (2294 + 307.42, 2334 + 341.53, and 2342 + 426.67 kcal/day, respectively). Alanine in plasma dropped significantly (p < .05): 10 mmol/L (311 +/- 55.88 mmol/L) at glycemia compared with 5 mmol/L (390 +/- 76 micromol/L) at insulinemia 250 mIU/L. It did not differ significantly from the values obtained at glycemia 5 mmol/L and insulinemia 1250 mIU/L (348 +/- 70.68 mmol/L). Even if the level of cytokines in sepsis was higher, there was no correlation between the insulin level in plasma (250 and 1250 mIU/L), glycemia (5 and 10 mmol/L) and cytokine level (IL-1beta, IL-2, IL-6, IL-8 and TNFalpha).

CONCLUSION

At insulinemia 250 mIU/L, a glucose level of 10 mmol/L seems to increase glucose uptake, oxidation, and storage compared with glycemia 5 mmol/L. This glucose uptake and oxidation at glycemia 10 mmol/L is comparable with the effect of extremely high insulinemia (1250 mIU/L) clamped at glycemia 5 mmol/L. A higher level of blood glucose or a high level of insulinemia significantly increases glucose uptake but not energy expenditure.

Patient survival, predictive factors and disease course of severe sepsis in Czech intensive care units: A multicentre, retrospective, observational study

BACKGROUND

Severe sepsis/septic shock is associated with high mortality. In Central Europe, there is a dearth of information on the prevalence and treatment of severe sepsis. The EPOSS (Data-based Evaluation and Prediction of Outcome in Severe Sepsis) project launched in 2011 was aimed at collecting data on patients with severe sepsis/septic shock.

METHODS

The EPOSS study processes data from the EPOSS project database, and is a retrospective, multicentre, observational study. This included all consecutive patients aged 18 and over who were admitted to participating ICUs from 1 January 2011 to 5 November 2013 and met the inclusion criteria of severe sepsis/septic shock. The primary endpoint was to analyse the relationship between in-hospital mortality (either in ICU or after discharge from ICU) and the type and number of fulfilled diagnostic and treatment interventions during the first 6 h after the diagnosis of severe sepsis/septic shock.

RESULTS

The collected dataset involved 1082 patients meeting the criteria of severe sepsis/septic shock. Following data validation, a final dataset of 897 patients was obtained. The average age of the patient group was 64.7 years; mortality at discharge from EPOSS ICUs was 35.5% and from hospital 40.7%. Of the 10 evaluated diagnostic and treatment interventions within the initial 6 hours of identifying severe sepsis/septic shock (i.e. fulfilment of SSC bundles), four or five diagnostic and treatment interventions were administered to 58.4% patients. Combined diagnostic and treatment interventions associated with the lowest in-hospital mortality were: CVP of ≥8-12 mm Hg & MAP of ≥65 mm Hg & Urine output at ≥0.5 mL/kg/h & Lactate of ≤4.0 mmol/L & Initial lactate measured & Antibiotics in the first hour. Lactate at <4 mmol/L and MAP of ≥65 mm Hg remained statistically significant even after adjustment for patient age and APACHE II score. Statistically significantly increased in-hospital mortality was found in patients admitted from general departments (45.7%) or from other ICUs (41.6%), compared to a lower in-hospital mortality of patients transferred from outpatient clinics (26.5%) or Emergency (38.0%). Severe sepsis/septic shock patients transferred from the department of internal medicine were associated with a higher in-hospital mortality (45.1%) than surgical patients (35.5%).

CONCLUSIONS

The most effective measures associated with the lowest in-hospital mortality in septic shock patients were CVP of ≥8-12 mm Hg, MAP of ≥65 mm Hg, urine output at ≥0.5 mL/kg/h, initial lactate level of ≤4.0 mmol/L and administration of antibiotics within the first hour.

Genome-wide association study of survival from sepsis due to pneumonia: an observational cohort study

BACKGROUND

Sepsis continues to be a major cause of death, disability, and health-care expenditure worldwide. Despite evidence suggesting that host genetics can influence sepsis outcomes, no specific loci have yet been convincingly replicated. The aim of this study was to identify genetic variants that influence sepsis survival.

METHODS

We did a genome-wide association study in three independent cohorts of white adult patients admitted to intensive care units with sepsis, severe sepsis, or septic shock (as defined by the International Consensus Criteria) due to pneumonia or intra-abdominal infection (cohorts 1-3, n=2534 patients). The primary outcome was 28 day survival. Results for the cohort of patients with sepsis due to pneumonia were combined in a meta-analysis of 1553 patients from all three cohorts, of whom 359 died within 28 days of admission to the intensive-care unit. The most significantly associated single nucleotide polymorphisms (SNPs) were genotyped in a further 538 white patients with sepsis due to pneumonia (cohort 4), of whom 106 died.

FINDINGS

In the genome-wide meta-analysis of three independent pneumonia cohorts (cohorts 1-3), common variants in the FER gene were strongly associated with survival (p=9·7 × 10(-8)). Further genotyping of the top associated SNP (rs4957796) in the additional cohort (cohort 4) resulted in a combined p value of 5·6 × 10(-8) (odds ratio 0·56, 95% CI 0·45-0·69). In a time-to-event analysis, each allele reduced the mortality over 28 days by 44% (hazard ratio for death 0·56, 95% CI 0·45-0·69; likelihood ratio test p=3·4 × 10(-9), after adjustment for age and stratification by cohort). Mortality was 9·5% in patients carrying the CC genotype, 15·2% in those carrying the TC genotype, and 25·3% in those carrying the TT genotype. No significant genetic associations were identified when patients with sepsis due to pneumonia and intra-abdominal infection were combined.

INTERPRETATION

We have identified common variants in the FER gene that associate with a reduced risk of death from sepsis due to pneumonia. The FER gene and associated molecular pathways are potential novel targets for therapy or prevention and candidates for the development of biomarkers for risk stratification.

FUNDING

European Commission and the Wellcome Trust.

Influence of insulin on glucose metabolism and energy expenditure in septic patients

Introduction

It is recognized that administration of insulin with glucose decreases catabolic response in sepsis. The aim of the present study was to compare the effects of two levels of insulinaemia on glucose metabolism and energy expenditure in septic patients and volunteers.

Methods

Glucose uptake, oxidation and storage, and energy expenditure were measured, using indirect calorimetry, in 20 stable septic patients and 10 volunteers in a two-step hyperinsulinaemic (serum insulin levels 250 and 1250 mIU/l), euglycaemic (blood glucose concentration 5 mmol/l) clamp. Differences between steps of the clamp (from serum insulin 1250 to 250 mIU/l) for all parameters were calculated for each individual, and compared between septic patients and volunteers using the Wilcoxon nonpaired test.

Results

Differences in glucose uptake and storage were significantly less in septic patients. The differences in glucose oxidation between the groups were not statistically significant. Baseline energy expenditure was significantly higher in septic patients, and there was no significant increase in either step of the clamp in this group; when comparing the two groups, the differences between steps were significantly greater in volunteers.

Conclusion

A hyperdynamic state of sepsis leads to a decrease in glucose uptake and storage in comparison with healthy volunteers. An increase in insulinaemia leads to an increase in all parameters of glucose metabolism, but the increases in glucose uptake and storage are significantly lower in septic patients. A high level of insulinaemia in sepsis increases glucose uptake and oxidation significantly, but not energy expenditure, in comparison with volunteers.

Effect of prone position on hepato-splanchnic hemodynamics in acute lung injury

OBJECTIVE

To evaluate the effects of prone position on hepato-splanchnic hemodynamics, metabolism and gut mucosal energy balance.

DESIGN

Prospective clinical study.

SETTING

Medical intensive care unit in a university hospital.

PATIENTS

Eleven hemodynamically stable patients with acute lung injury (ALI) requiring mechanical ventilation.

INTERVENTION

Patients were studied in the supine position, after 90 min in the prone position and after 90 min of supine repositioning.

MEASUREMENTS AND RESULTS

In addition to global hemodynamics we measured intra-abdominal pressure (IAP, bladder), hepato-splanchnic blood flow (HSBF, steady state indocyanine green technique using a hepatic vein catheter) and gastric mucosal-arterial PCO(2) gap (PCO(2) gap, automated air tonometry). Systemic hemodynamics did not change during the whole study. Prone positioning did not significantly affect IAP. HSBF as well as splanchnic oxygen consumption remained unaltered, too. Similarly, neither liver lactate uptake nor indocyanine green extraction were influenced by positional changes. Finally, stable regional hemodynamics were accompanied by an unchanged PCO(2) gap.

CONCLUSION

We conclude that if IAP and systemic hemodynamics remain unaffected, the prone position in ALI patients compromises neither hepato-splanchnic perfusion nor gastric mucosal energy balance.

Submaximal exercise in healthy volunteers: the relationship between gastric mucosal and systemic energy status

The effect of exercise on gastric mucosal energy status has not been fully elucidated. The aim of this study was to evaluate the impact of submaximal cycling on gastric mucosal energy balance and its relationship to changes in systemic energy status. Ten healthy volunteers (age 20-40 years) were investigated at rest (BL), during 30 min of submaximal exercise (E) on bicycle ergometry and during the 30 min after the completion of cycling. Gastric mucosal PCO(2) ( P(gm)CO(2)) was measured by air tonometry at 10-min intervals and the gastric mucosal-arterial PCO(2) difference ( PCO(2)gap) was calculated. Hemodynamics, arterial blood gases, lactate and pyruvate were also measured. PCO(2)gap significantly increased throughout exercise [BL: 0.2 kPa (median), -0.1-0.6 kPa (25th-75th percentiles); E(10 min): 1.0 kPa, 0.8-1.7 kPa; E(20 min): 1.35 kPa, 0.8-1.8 kPa; E(30 min): 1.5 kPa, 0.9-2.0 kPa]. The early changes in PCO(2)gap ( PCO(2)gap at E(10 min) minus PCO(2)gap at BL) correlated significantly and positively with corresponding changes in arterial lactate ( r(2)=0.58, P<0.05) and lactate-to-pyruvate ratio ( r(2)=0.72, P<0.05). On recovery, all metabolic parameters normalized within 30 min. We conclude that submaximal cycling in volunteers leads to the early derangement of gastric mucosal energy balance. The time course of PCO(2)gap parallels changes in systemic energy status.

Effects of ultrafiltration, dialysis, and temperature on gas exchange during hemodiafiltration: a laboratory experiment

To study gas exchange in the filter during continuous venovenous hemodiafiltration (CVVHDF), an air-tight heated mixing chamber with adjustable CO2 supply was constructed and connected to a CVVHDF monitor. Bicarbonate-free crystalloid (Part 1) and packed red blood cell (Part 2) solutions were circulated at 150 ml x min(-1). Gas exchange expressed as pre-postfilter difference in CO2 and O2 contents was measured at different CVVHDF settings and temperatures of circulating and dialysis solutions. Ultrafiltration was most efficacious for CO2 removal (at 1,000 ml x h(-1) ultrafiltration CO2 losses reached 13% of prefilter CO2 content). Addition of dialysis (1,000 ml x h(-1)) increased CO2 loss to 17% and at maximal parameters (filtration 3,000 ml x h(-1), dialysis 2,500 ml x h(-1)), the loss of CO2 amounted to 35% of prefilter content. Temperature changes of circulating and/or dialysis fluids had no significant impact on CO2 losses. The O2 exchange during CVVHDF was negligible. Currently used CVVHDF is only marginally effective in CO2 removal. Higher volume ultrafiltration combined with dialysis can be expected to reach clinical significance.

Effect of dopexamine on outcome after major abdominal surgery: a prospective, randomized, controlled multicenter study. European Multicenter Study Group on Dopexamine in Major Abdominal Surgery

OBJECTIVE

To test the hypothesis that dopexamine reduces postoperative mortality and morbidity in high-risk, major abdominal surgery patients, when given to fluid-resuscitated patients starting before the operation and continued for 24 hrs after surgery.

DESIGN

Prospective, randomized, controlled, double-blind multicenter trial.

SETTING

Intensive care units in 13 hospitals from six European countries.

PATIENTS

A total of 412 patients with predefined high-risk criteria, undergoing major abdominal surgery with an expected duration of at least 1.5 hrs.

INTERVENTIONS

The patients received placebo (n = 140), dopexamine at 0.5 microg/kg/min (n = 135), or dopexamine at 2.0 microg/kg/ min (n = 137) starting after preoperative hemodynamic stabilization and continued for 24 hrs after surgery.

MEASUREMENTS AND MAIN RESULTS

The primary outcome variable was mortality at 28 days. Analysis was by intention to treat. Dopexamine had no effect on mortality (at 28 days, 13%, 7%, and 15%, for the groups receiving placebo, dopexamine at 0.5 microg/kg/ min, and dopexamine at 2.0 microg/kg/min, respectively), despite the expected dose-dependent hemodynamic responses. No effect was observed on the occurrence of organ dysfunction, duration of intensive care unit stay, or length of hospital stay.

CONCLUSION

We conclude that dopexamine in doses that result in increased cardiac output and oxygen delivery after preoperative stabilization with fluids does not improve outcome after major abdominal surgery compared with fluids alone. Based on post hoc subgroup analysis and stratification according to the number of risk factors, we suggest that the concept should be further tested in patients at higher risk of complications or undergoing emergency surgery.