[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.

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).

Ascorbic Acid in postoperative intensive care patients - biochemical aspects and clinical experience

The transport mechanisms of ascorbic acid (AA) are described. The metabolism of AA and its function as an antioxidant are covered in some detail. Subsequently, indications for postoperative substitution are discussed. The supplementation of up to 300 mg of AA per day in postoperative intensive care unit patients during par-/enteral nutrition is recommended to prevent hypovitaminosis. It is not clear if this is the optimal dosage of AA in postoperative/-trauma patients. New aspects for an AA substitution are discussed.

Metabolic clearance of the antioxidant ascorbic acid in surgical patients

BACKGROUND

A reduction of plasma ascorbic acid concentration in the post-operative period has been well documented and is associated with an increase in post-operative complications. The underlying reason for the decreased concentration of ascorbic acid in the plasma is not clear. However, only an increased post-operative requirement for ascorbic acid would justify a substitution. Therefore, we investigated the pre-operative and post-operative metabolic clearance of ascorbic acid.

MATERIALS AND METHODS

We calculated the metabolic clearance subsequent to intravenous bolus injection of 6 mg ascorbic acid/kg body weight in 15 patients before and after they underwent major maxillofacial surgery. Blood samples were taken before and 5, 15, 30, 45, 60, 90, 120, and 240 min after administration of ascorbic acid before and after the operation. Urine was collected. Ascorbic acid in plasma and urine was analyzed using a high performance liquid chromatographic technique.

RESULTS

The pre-operative metabolic clearance was 7.6 +/- 2.22 l/h (mean +/- SD), increasing significantly to 12.1 +/- 4.87 l/h on the first post-operative day (P < 0.001). Doses of approximately 1150 mg ascorbic acid would be necessary to compensate for the observed loss and to raise plasma ascorbic acid to high normal values.

CONCLUSIONS

There is a significantly increased post-operative metabolic clearance of ascorbic acid that might be considered when framing future dose recommendations in post-operative patients.

Early postoperative substitution procedure of the antioxidant ascorbic acid

BACKGROUND

Postoperatively reduced concentration of ascorbic acid (AA) in plasma (< or =45.5 micromol/l (< or =800 microg/dl)) is commonly interpreted as increased metabolic requirements, but it is not shown yet that the patient benefits from a substitution toward normal levels of AA. This is due to the missing knowledge on how to substitute AA effectively to normal plasma values in postoperative patients. Therefore, a postoperative AA substitution procedure "overnight" to normal values in plasma was investigated on a postoperative intensive care unit (ICU) in a university hospital.

MATERIAL AND METHODS

Fifty-seven operated patients were randomly assigned to a control- or intervention group (CG and IG, respectively). In all patients, the AA plasma concentration was analysed preoperatively and on the first three postoperative days. Patients of the IG received AA intravenously up to four times within 12 h depending upon the initial AA concentration (<34.1 micromol/l (4x500 mg AA); < or =56.8 micromol/l (2x500 mg AA); < or =68.2 micromol/l (1x500 mg AA)).

RESULTS

The preoperative and early postoperative AA values did not differ between the groups. On the first postoperative day in both groups the plasma concentration was lowered (< or =45.5 micromol/l) in 23 of all patients (CG: 85.18%; IG: 82.14%). In the IG, the dosage regime increased the AA plasma concentration to > or =45.5 micromol/l in 26 of 28 (92.86%) patients overnight.

CONCLUSION

The investigated substitution procedure is sufficient to increase AA plasma concentration overnight to normal or high normal values in postoperative ICU patients.

Ceftazidime determination in serum by high-pressure liquid chromatography

A rapid and sensitive high-pressure liquid chromatographic method with simple sample preparation was developed for the quantitative analysis of the beta-lactam antibiotic ceftazidime (CAS 78439-06-2, Fortum). A good linear relationship was established between the peak area and the amount of ceftazidime injected over a concentration range of 1 to 200 microg/ml. The detection limit of the method was calculated to be 0.9 microg/ml. Stability was shown at 4 degrees C and at -196 degrees C for time periods of 2 h and 84 days, respectively.

Determination of alpha-tocopherol in plasma by high performance liquid chromatography with fluorescence detection and stability of alpha-tocopherol under different conditions

In order to study the clinical effects of the antioxidant alpha-tocopherol (tocofersolan, CAS 30999-06-5) a simple, robust, sensitive and reliable high performance liquid chromatography (HPLC) method using fluorescence detection for the daily measurement of alpha-tocopherol concentration in plasma is described. Several methods of HPLC analysis using fluorescence techniques are published, however, investigations of the stability of alpha-tocopherol during sample preparation under different conditions are relevant in the routine measurements and have to date not been reported. Therefore a modified method, both sensitive and robust, qualified for the day-by-day measurement of alpha-tocopherol in plasma was established and the stability of alpha-tocopherol during sample preparation was analysed under different conditions. This method enables the complete separation of alpha-tocopherol from other compounds within 14 min. In addition, investigations on the stability of alpha-tocopherol during sample preparation showed the necessity of rapid sample preparation without delay. Prepared samples can be stored in liquid nitrogen for at least 56 days.

Single preoperative oral application of ascorbic acid does not affect postoperative plasma levels of ascorbic acid

BACKGROUND AND AIMS

A decrease in ascorbic acid (AA) plasma concentration is well known during the postoperative period and postulated to be caused by increased radical scavenging activity in response to surgical trauma. This often affects postoperative patients and is associated with multiple organ failure. Therefore, substitution of AA could potentially decrease the risk of postoperative complications. This study examines the effect of preoperative oral administration of 1,000 mg AA on the postoperative AA plasma concentration.

METHODS

54 patients were randomly split into two groups; patients in group 1 received no AA preoperatively while group 2 received oral AA (1,000 mg). Plasma samples were obtained preoperatively and on the first postoperative day for AA analysis (HPLC).

RESULTS

In both groups the AA concentration was normal preoperatively and reduced postoperatively.

CONCLUSION

A preoperative substitution of 1,000 mg AA is not sufficient to prevent postoperative lowered plasma concentration.

Clearance of ascorbic acid in plasma in patients before major maxillofacial surgery compared with that in volunteers

Reduced concentration of ascorbic acid (AA) in plasma is often observed in tumor patients. Besides malnutrition, an increased AA consumption in tumor patients is discussed as a main reason for reduced AA concentration in plasma. A reduced AA concentration caused by malnutrition would not influence the total clearance (Cltot) of AA in plasma; however, a change in AA consumption would alter the Cltot. To investigate this further, a study was carried out on 20 patients hospitalized for major maxillofacial surgery and 20 volunteers. The Cltot of AA in plasma after bolus injection of AA (4 mg/kg body wt) in tumor patients was compared with that in volunteers. AA concentration in plasma (P < 0.05) was significantly lower in tumor patients (median and 25th and 75th percentiles: 23.7, 14.6, and 32.7 mumol/l) than in volunteers (median and 25th and 75th percentiles: 66.5, 59.6, and 78.6 mumol/l). No significant change in Cltot was observed for tumor patients (median and 25th and 75th percentiles: 11.5, 8.0, and 14.0 l/h) compared with volunteers (median and 25th and 75th percentiles: 11.3, 9.9, and 13.2 l/h). No indication of an increased consumption of AA in tumor patients could be detected. The lowered concentration of AA in plasma observed in our patients might be the result of a reduced AA intake.

Postoperative altered plasma growth hormone levels--a predictor for postoperative complications? A case report

We compared the onset of predictors for postoperative complications (lactate, total T2 (tT2), total T4 (tT4) and cortisone) retrospectively with the onset of altered growth hormone (GH) concentration in a patient who had had a lethal postoperative outcome and in 13 patients who were without postoperative complications for a period of 24 hours postoperatively. Compared with the values of the patients without postoperative complications, GH values were elevated (68-fold) 1 h after surgery to 103 ng/ml and lactate was increased (12-fold) to 12.7 mmol/l at 6 h postoperatively in the patient with the lethal outcome. The other parameters measured (tT3, tT4 and cortisone) showed no rapid alteration during the first hours postoperatively. This case report suggests that the rapid postoperative onset of raised GH concentration in plasma may be an earlier marker for postoperative complications than the 'established' predictors.

Determination of ascorbic acid in plasma and urine by high performance liquid chromatography with ultraviolet detection

A reliable simple reversed-phase liquid chromatographic method for the routine determination of ascorbic acid in plasma and urine with ultraviolet detection is described. This method enables the complete separation of the ascorbic acid peak from others with a recovery of above 95% within 8 minutes. The method can be used for analysing multiple samples within a day. In addition, the storage conditions and stability of ascorbic acid in plasma and urine were investigated. Samples of plasma and urine can be stored on ice in darkness for at least 60 min without reduction of ascorbic acid concentration. Prepared samples can be stored in darkness at 4 degrees C for at least 120 min and in liquid nitrogen for 42 days.

Postoperative pattern of various hormonal and metabolic variables. A pilot study in patients without complications following cardiac surgery

The use of single predictors for threatening postoperative complications are widely accepted. However, a typical pattern of multiple parameters could be more helpful than a single predictor. To study this hypothesis, various variables of normal postoperative changes in patients without postoperative complications were investigated. Secondly, this pattern needs to be compared in the future with those findings in patients with postoperative complications. Blood parameters of 13 patients undergoing cardiovascular surgery without postoperative complications for 24 hours were evaluated. Samples were obtained on the afternoon before the operation and 1, 3, 6, 12 and 24 hours after the end of surgery. At one hour postoperation increased levels of the following parameters were noted: growth hormone (p < 0.0001), glucose (p < 0.0001), insulin (p < 0.001), c-peptide (p < 0.001), lactate (p < 0.002), glutamate (p < 0.0001), aspartate (p < 0.001) and total amino acids (p < 0.05), although the concentration of some amino acids decreased. Three hours postoperatively free fatty acids (p < 0.05) were increased. Total-T3 concentrations were reduced postoperatively. Other parameters were not altered. Most of the parameters returned to normal values during the period of observation.

[Plasma renin activity and aldosterone behavior in critically ill patients]

To investigate the influence of critical illness on plasma renin activity and aldosterone levels and to examine potential inhibitory effects of dopamine therapy on aldosterone responsiveness, we measured plasma renin activity, and potassium and creatinine in serum, as well as the responses of aldosterone, cortisol and prolactin levels to TRH 200 micrograms i.v. + Synacthen 0.25 mg i.v. in 63 unselected, critically ill patients (32 females, 31 males, aged 18-84 years). Of the patients 19 received dopamine treatment (3-13 micrograms/kg/min i.v.); 21 of the patients died in the further course of their disease. Plasma renin activity was increased in 66.7% of the patients and aldosterone levels were elevated in 90.5% of the patients. There were correlations (P less than 0.05) of lethality with plasma renin activity and cortisol levels and correlations (P less than 0.01) of aldosterone concentrations with plasma renin activity and cortisol levels. Whereas dopamine treatment had no inhibitory effect on aldosterone levels before and after stimulation, prolactin stimulation was decreased in dopamine-treated patients. Thus, dopamine does not generally lose its potency of hormone inhibition in critically ill patients, but has no influence on the secondary aldosteronism developing regularly in the early phase of critical illness, which is apparently mainly due to the stimulatory effect of ACTH (or ACTH-related pituitary peptides) and is considered an epiphenomen of the stress mechanisms acting upon the patients in this condition.