Overcoming barriers to the mobilisation of patients in an intensive care unit

We conducted a quality improvement project aimed at increasing the frequency of mobilisation in our ICU. We designed a four-part quality improvement project comprising: an audit documenting the baseline frequency of mobilisation; a staff survey evaluating perceptions of the barriers to mobilisation; identification of barriers that were amenable to change and implementation of strategies to address these; and a follow-up audit to determine their effectiveness. The setting was a tertiary care, urban, public hospital ICU in South Australia. All patients admitted to the ICU during the two audit periods were included in the audits, while all permanent/semi-permanent ICU staff were eligible for inclusion in the staff survey. We found that patient- and institution-related factors had the greatest impact on the mobilisation of patients in our ICU. Barriers identified as being amenable to change included insufficient staff education about the benefits of mobilisation, poor interdisciplinary communication and lack of leadership regarding mobilisation. Various strategies were implemented to address these barriers over a three-month period. Multivariable analyses showed that three out of four mobility outcomes did not significantly change between the baseline and follow-up audits, with a significant difference in favour of the baseline audit found for the fourth mobility outcome (maximum level of mobility). We concluded that implementing relatively simple measures to improve staff education, interdisciplinary communication and leadership regarding early progressive mobilisation was ineffective at improving mobility outcomes for patients in a large tertiary-level Australian ICU. Other strategies, such as changing sedation practices and/or increasing staffing, may be required to improve mobility outcomes of these patients.

Nutrition support practices in critically ill head-injured patients: a global perspective

Background

Critical illness following head injury is associated with a hypermetabolic state but there are insufficient epidemiological data describing acute nutrition delivery to this group of patients. Furthermore, there is little information describing relationships between nutrition and clinical outcomes in this population.

Methods

We undertook an analysis of observational data, collected prospectively as part of International Nutrition Surveys 2007-2013, and extracted data obtained from critically ill patients with head trauma. Our objective was to describe global nutrition support practices in the first 12 days of hospital admission after head trauma, and to explore relationships between energy and protein intake and clinical outcomes. Data are presented as mean (SD), median (IQR), or percentages.

Results

Data for 1045 patients from 341 ICUs were analyzed. The age of patients was 44.5 (19.7) years, 78 % were male, and median ICU length of stay was 13.1 (IQR 7.9-21.6) days. Most patients (94 %) were enterally fed but received only 58 % of estimated energy and 53 % of estimated protein requirements. Patients from an ICU with a feeding protocol had greater energy and protein intakes (p <0.001, 0.002 respectively) and were more likely to survive (OR 0.65; 95 % CI 0.42-0.99; p = 0.043) than those without. Energy or protein intakes were not associated with mortality. However, a greater energy and protein deficit was associated with longer times until discharge alive from both ICU and hospital (all p <0.001).

Conclusion

Nutritional deficits are commonplace in critically ill head-injured patients and these deficits are associated with a delay to discharge alive.

Effect of Critical Illness on Triglyceride Absorption

BACKGROUND

Adequate nutrition support for critically ill patients optimizes outcome, and enteral feeding is the preferred route of nutrition. Small intestinal glucose absorption is frequently impaired in critical illness. Despite lipid being a major constituent of liquid nutrient administered, there is little information about lipid absorption during critical illness.

OBJECTIVES

To determine small intestinal lipid, as well as glucose, absorption in critical illness compared with health.

MATERIALS AND METHODS

Twenty-nine mechanically ventilated critically ill patients and 16 healthy volunteers were studied. Liquid nutrient (60 mL, 1 kcal/mL), containing 200 µL (13)C-triolein and 3 g 3-O-methyl-glucose (3-OMG), was infused directly into the duodenum at a rate of 2 kcal/min. Exhaled (13)CO2 and serum 3-OMG concentrations were measured at timed intervals over 360 minutes. Lipid absorption was measured as the cumulative percentage dose (cPDR) of (13)CO2 recovered at 360 minutes. Glucose absorption was measured as the area under the 3-OMG concentration curve. Data are median (range) and analyzed using the Mann-Whitney U and Pearson correlation tests.

RESULTS

Lipid absorption was markedly less in the critically ill (cPDR(13)CO2: patients, 22.6% [0%-100%] vs healthy participants, 40.7% [5.3%-84.7%]; P = .018). While glucose absorption was less at 60 minutes in the critically ill (3-OMG60: 13.2 [3.5-29.5] vs 21.1 [9.3-31.9] mmol/L·min; P = .003), this was not apparent at 360 minutes (3-OMG360: 92.7 [54.5-147.9] vs 107.9 [64.0-168.7] mmol/L·min; P = .126). There was no relationship between lipid and glucose absorption.

CONCLUSION

Small intestinal absorption of lipid is diminished during critical illness.

Anti-seizure prophylaxis in critically ill patients with traumatic brain injury in an intensive care unit

The objectives of this prospective observational study were to determine the proportion of patients with traumatic brain injury who received effective anti-seizure prophylaxis. The study was conducted in a tertiary level ICU of a major trauma referral centre between February 2012 and August 2013. A total of 2361 patients were admitted to the ICU in this study period, of whom125 patients (index) with traumatic head injury were included in this study. The patients had a mean age of 45 years (SD=19), a mean score on the Glasgow Coma Scale of 9 (SD=4), a mean injury severity score of 27 (SD=13) and a mean APACHE III score of 55 (SD=27). Only 13.6 % (17 of 125) of patients were given anti-seizure prophylaxis and phenytoin levels were measured in 9.6% (12 of 125). Although all 12 patients achieved an effective concentration for phenytoin therapy (>40 µmol/l) after the loading dose, no patient had their target concentration consistently maintained in the recommended therapeutic range (40 to 80 µmol/l) throughout the seven-day monitoring period. There was wide fluctuation in phenytoin levels in the patients in this study. Twenty-two (18%) of the index patients had post-traumatic seizures, indicating a high prevalence for this study. Poor compliance with guidelines could possibly explain this phenomenon. Future studies are needed to look at the dosing and monitoring of phenytoin and/or alternative anti-seizure prophylaxis in patients with traumatic brain injury.

Measurement of gastric emptying in the critically ill

BACKGROUND & AIMS

Enteral nutrition is important in critically ill patients and is usually administered via a nasogastric tube. As gastric emptying is frequently delayed, and this compromises the delivery of nutrient, it is important that the emptying rate can be quantified.

METHODS

A comprehensive search of MEDLINE/PubMed, of English articles, from inception to 1 July 2014. References of included manuscripts were also examined for additional studies.

RESULTS

A number of methods are available to measure gastric emptying and these broadly can be categorised as direct- or indirect-test and surrogate assessments. Direct tests necessitate visualisation of the stomach contents during emptying and are unaffected by liver or kidney metabolism. The most frequently used direct modality is scintigraphy, which remains the 'gold standard'. Indirect tests use a marker that is absorbed in the proximal small intestine, so that measurements of the marker, or its metabolite measured in plasma or breath, correlates with gastric emptying. These tests include drug and carbohydrate absorption and isotope breath tests. Gastric residual volumes (GRVs) are used frequently to quantify gastric emptying during nasogastric feeding, but these measurements may be inaccurate and should be regarded as a surrogate measurement. While the inherent limitations of GRVs make them less suitable for research purposes they are often the only technique that is available for clinicians at the bedside.

CONCLUSIONS

Each of the available techniques has its strength and limitations. Accordingly, the choice of gastric emptying test is dictated by the particular requirement(s) and expertise of the investigator or clinician.

Depletion of high-affinity corticosteroid-binding globulin corresponds to illness severity in sepsis and septic shock; clinical implications

OBJECTIVE

Corticosteroid-binding globulin (CBG) is cleaved by neutrophil elastase converting the high-affinity (haCBG) conformation of CBG to a low-affinity (laCBG) conformation with a ninefold reduced cortisol-binding affinity. These in vitro data suggest that cortisol release by CBG cleavage results in the targeted delivery of cortisol to areas of inflammation. Our objective was to determine whether CBG cleavage alters circulating levels of haCBG and laCBG in vivo in proportion to sepsis severity.

DESIGN

Prospective, observational cohort study in an adult tertiary level Intensive Care Unit in Adelaide, Australia.

PATIENTS

Thirty-three patients with sepsis or septic shock grouped by illness severity [sepsis, septic shock survivors, septic shock nonsurvivors and other shock].

MEASUREMENTS

Plasma levels of haCBG and laCBG were assessed using a recently developed in-house assay in patients. Plasma total and free cortisol levels were also measured.

RESULTS

Plasma total CBG and haCBG levels fell significantly, in proportion to disease severity (P < 0·0001 for both). There was a nonsignificant increase in free and total cortisol as illness severity worsened (P = 0·19 and P = 0·39, respectively). Illness severity was better correlated with haCBG levels than either free or total cortisol levels.

CONCLUSIONS

Increasing illness severity in sepsis and septic shock is associated with markedly reduced circulating haCBG concentrations in vivo. We propose that low levels of haCBG in chronic inflammation may limit the availability of cortisol to inflammatory sites, perpetuating the inflammatory process.

Hyperglycemia potentiates the slowing of gastric emptying induced by exogenous GLP-1

OBJECTIVE

Acute hyperglycemia markedly slows gastric emptying. Exogenous GLP-1 also slows gastric emptying, leading to diminished glycemic excursions. The primary objective was to determine whether hyperglycemia potentiates the slowing of gastric emptying induced by GLP-1 administration.

RESEARCH DESIGN AND METHODS

Ten healthy participants were studied on 4 separate days. Blood glucose was clamped at hyperglycemia using an intravenous infusion of 25% dextrose (∼12 mmol/L; hyper) on 2 days, or maintained at euglycemia (∼6 mmol/L; eu) on 2 days, between t = -15 and 240 min. During hyperglycemic and euglycemic days, participants received intravenous GLP-1 (1.2 pmol/kg/min) and placebo in a randomized double-blind fashion. At t = 0 min, subjects ingested 100 g beef mince labeled with 20 MBq technetium-99m-sulfur colloid and 3 g 3-O-methyl-glucose (3-OMG), a marker of glucose absorption. Gastric emptying was measured scintigraphically from t = 0 to 240 min and serum 3-OMG taken at regular intervals from t = 15 to 240 min. The areas under the curve for gastric emptying and 3-OMG were analyzed using one-way repeated-measures ANOVA with Bonferroni-Holm adjusted post hoc tests.

RESULTS

Hyperglycemia slowed gastric emptying (eu/placebo vs. hyper/placebo; P < 0.001) as did GLP-1 (eu/placebo vs. eu/GLP-1; P < 0.001). There was an additive effect of GLP-1 and hyperglycemia, such that gastric emptying was markedly slower compared with GLP-1 administration during euglycemia (eu/GLP-1 vs. hyper/GLP-1; P < 0.01).

CONCLUSIONS

Acute administration of exogenous GLP-1 profoundly slows gastric emptying during hyperglycemia in excess of the slowing induced by GLP-1 during euglycemia. Studies are required to determine the effects of hyperglycemia on gastric emptying with the subcutaneously administered commercially available GLP-1 agonists in patients with type 2 diabetes.

Gastrointestinal dysfunction relating to the provision of nutrition in the critically ill

PURPOSE OF REVIEW

During critical illness, enteral nutrition remains central to clinical care and an understanding of gut dysfunction is therefore important. Contemporary data have contributed to our knowledge in this area and this review will concentrate on recently published studies.

RECENT FINDINGS

It is difficult to precisely measure gastric emptying and nutrient absorption as part of routine clinical care. However, techniques for the measurement of these parameters for research purposes have been refined, studied and validated. These methodologies allow the evaluation of novel treatments that modulate gastric emptying. Quantification and an understanding of the mechanisms of nutrient malabsorption may facilitate the development of therapeutic agents to improve absorption and/or formulae, which are more readily absorbed, thereby improving nutritional and clinical outcomes.

SUMMARY

Improved understanding of gut pathophysiology in critical illness provides opportunities for the development and testing of novel and targeted treatment strategies, with the objective to improve clinical outcomes in this group.

Effects of glucose-dependent insulinotropic polypeptide on gastric emptying, glycaemia and insulinaemia during critical illness: a prospective, double blind, randomised, crossover study

INTRODUCTION

Insulin is used to treat hyperglycaemia in critically ill patients but can cause hypoglycaemia, which is associated with poorer outcomes. In health glucose-dependent insulinotropic polypeptide (GIP) is a potent glucose-lowering peptide that does not cause hypoglycaemia. The objectives of this study were to determine the effects of exogenous GIP infusion on blood glucose concentrations, glucose absorption, insulinaemia and gastric emptying in critically ill patients without known diabetes.

METHODS

A total of 20 ventilated patients (Median age 61 (range: 22 to 79) years, APACHE II 21.5 (17 to 26), BMI 28 (21 to 40) kg/m(2)) without known diabetes were studied on two consecutive days in a randomised, double blind, placebo controlled, cross-over fashion. Intravenous GIP (4 pmol/kg/min) or placebo (0.9% saline) was infused between T = -60 to 300 minutes. At T0, 100 ml of liquid nutrient (2 kcal/ml) containing 3-O-Methylglucose (3-OMG), 100 mcg of Octanoic acid and 20 MBq Tc-99 m Calcium Phytate, was administered via a nasogastric tube. Blood glucose and serum 3-OMG (an index of glucose absorption) concentrations were measured. Gastric emptying, insulin and glucagon levels and plasma GIP concentrations were also measured.

RESULTS

While administration of GIP increased plasma GIP concentrations three- to four-fold (T = -60 23.9 (16.5 to 36.7) versus T = 0 84.2 (65.3 to 111.1); P <0.001) and plasma glucagon (iAUC300 4217 (1891 to 7715) versus 1232 (293 to 4545) pg/ml.300 minutes; P = 0.04), there were no effects on postprandial blood glucose (AUC300 2843 (2568 to 3338) versus 2819 (2550 to 3497) mmol/L.300 minutes; P = 0.86), gastric emptying (AUC300 15611 (10993 to 18062) versus 15660 (9694 to 22618) %.300 minutes; P = 0.61), glucose absorption (AUC300 50.6 (22.3 to 74.2) versus 64.3 (9.9 to 96.3) mmol/L.300 minutes; P = 0.62) or plasma insulin (AUC300 3945 (2280 to 6731) versus 3479 (2316 to 6081) mU/L.300 minutes; P = 0.76).

CONCLUSIONS

In contrast to its profound insulinotropic effect in health, the administration of GIP at pharmacological doses does not appear to affect glycaemia, gastric emptying, glucose absorption or insulinaemia in the critically ill patient.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry ACTRN12612000488808. Registered 3 May 2012.

International observational study of nutritional support in mechanically ventilated patients following burn injury

INTRODUCTION

It has been proposed that nutritional therapy in critically ill patients after major burn reduces mortality. However, the actual practice of nutrient delivery, and the effect on outcome, has not been described.

STUDY OBJECTIVES

To evaluate international practices related to nutritional support and outcomes in mechanically ventilated patients with burn injury.

METHODS

Data from the International Nutrition Surveys (2007-2011) for patients with a primary diagnosis of burn were extracted and analysed.

RESULTS

Eighty-eight of 90 patients (aged 16-84 years) received enteral nutrition. The median time for initiation of enteral feeding was 17 h [range 0-65]. Fifty patients (57%) had interruptions to nutrient delivery, most often these interruptions were fasting for operative procedures. There were substantive energy and protein deficits [943 (654) kcal/day and 49 (41) g/day, respectively; mean (SD)]. Nineteen (21%) patients died within 60 days of admission, and the energy and protein deficits were greater in those that died compared with survivors [died vs. survived, energy: 1251 (742) vs. 861 (607) kcal/d; p=0.02; and protein 67(42) vs. 44(39) g/d; p=0.03]. Energy and protein deficits were associated with increased mortality with the greater the deficit, the stronger the association with death (odds ratio for death: energy deficit/100 kcal 1.10 (1.01, 1.19); p=0.028 and protein/10 g 1.16 (1.01, 1.33); p=0.037). Results were similar and remained significant after adjusting for severity of illness.

CONCLUSIONS

Mechanically ventilated patients following burn develop substantial energy and protein deficits, with lesser deficits observed in survivors.

Use of a concentrated enteral nutrition solution to increase calorie delivery to critically ill patients: a randomized, double-blind, clinical trial

BACKGROUND

Critically ill patients typically receive ∼60% of estimated calorie requirements.

OBJECTIVES

We aimed to determine whether the substitution of a 1.5-kcal/mL enteral nutrition solution for a 1.0-kcal/mL solution resulted in greater calorie delivery to critically ill patients and establish the feasibility of conducting a multicenter, double-blind, randomized trial to evaluate the effect of an increased calorie delivery on clinical outcomes.

DESIGN

A prospective, randomized, double-blind, parallel-group, multicenter study was conducted in 5 Australian intensive care units. One hundred twelve mechanically ventilated patients expected to receive enteral nutrition for ≥2 d were randomly assigned to receive 1.5 (n = 57) or 1.0 (n = 55) kcal/mL enteral nutrition solution at a rate of 1 mL/kg ideal body weight per hour for 10 d. Protein and fiber contents in the 2 solutions were equivalent.

RESULTS

The 2 groups had similar baseline characteristics (1.5 compared with 1.0 kcal/mL). The mean (±SD) age was 56.4 ± 16.8 compared with 56.5 ± 16.1 y, 74% compared with 75% were men, and the Acute Physiology and Chronic Health Evaluation II score was 23 ± 9.1 compared with 22 ± 8.9. The groups received similar volumes of enteral nutrition solution [1221 mL/d (95% CI: 1120, 1322 mL/d) compared with 1259 mL/d (95% CI: 1143, 1374 mL/d); P = 0.628], which led to a 46% increase in daily calories in the group given the 1.5-kcal/mL solution [1832 kcal/d (95% CI: 1681, 1984 kcal/d) compared with 1259 kcal/d (95% CI: 1143, 1374 kcal/d); P < 0.001]. The 1.5-kcal/mL solution was not associated with larger gastric residual volumes or diarrhea. In this feasibility study, there was a trend to a reduced 90-d mortality in patients given 1.5 kcal/mL [11 patients (20%) compared with 20 patients (37%); P = 0.057].

CONCLUSIONS

The substitution of a 1.0- with a 1.5-kcal/mL enteral nutrition solution administered at the same rate resulted in a 46% greater calorie delivery without adverse effects. The results support the conduct of a large-scale trial to evaluate the effect of increased calorie delivery on clinically important outcomes in the critically ill.

Dietary supplementation contributes to lifestyle improvement in hypercholesterolemic patients in real-life contexts

AIMS

Assess the evolution of cardiovascular lifestyle behaviors in hypercholesterolemic patients concomitantly with changes in their daily intake of phytosterol-supplemented yoghurt (Phyto-SY).

METHODS

Nationwide prospective observational study conducted in general practices across France and Spain. Each practitioner suggested lifestyle changes to five consecutive patients with hypercholesterolemia (whether or not they were taking hypocholesterolemic drugs) and recommended daily consumption of Phyto-SY. The study design involved an inclusion visit, a patient's self-monitoring assessment after 1 month, and a final visit after 4 months. Primary evaluation criterion: changes in dietary habits assessed by a standardized Nutritional Lifestyle score. Secondary criteria: changes in lipid profile, anthropometry (waist circumference) and lifestyle behavior.

RESULTS

A total of 2376 hypercholesterolemic patients (of whom 54.8% were women) were included. The average age was 56.2 years old. The Nutritional Lifestyle score improved from 15.4 ± 5.4 to 8.7 ± 4.0 (p < 0.0001). Total cholesterol decreased by 10.6% (<0.0001), HDL-C increased by 8.0% (<0.0001), and LDL-C fell by 12.7% (<0.0001). Similar results were observed in patients treated with statins and those who were not. Frequency of walking (>30 min) increased from 59.3% to 78.3% (p < 0.0001). The overweight rate decreased from 22.8% to 17.5% (p < 0.0001) and waist circumference from 94.6 ± 13.3 cm to 93.0 ± 12.8 cm (p < 0.0001). Nutritional Lifestyles and other lifestyle markers' improvement were parallel to adherence to Phyto-SY adherence.

CONCLUSION

Improvements in Nutritional Lifestyle scores, which included regular consumption of Phyto-SY over 4 months, was significantly linked to healthier lifestyles and to beneficial modifications in atherogenic lipid profiles, which reflected patient empowerment in a 'real life' context.

Dysglycaemia in the critically ill and the interaction of chronic and acute glycaemia with mortality

PURPOSE

Hyperglycaemia is common in the critically ill. The objectives of this study were to determine the prevalence of critical illness-associated hyperglycaemia (CIAH) and recognised and unrecognised diabetes in the critically ill as well as to evaluate the impact of premorbid glycaemia on the association between acute hyperglycaemia and mortality.

METHODS

In 1,000 consecutively admitted patients we prospectively measured glycated haemoglobin (HbA1c) on admission, and blood glucose concentrations during the 48 h after admission, to the intensive care unit. Patients with blood glucose ≥7.0 mmol/l when fasting or ≥11.1 mmol/l during feeding were deemed hyperglycaemic. Patients with acute hyperglycaemia and HbA1c <6.5% (48 mmol/mol) were categorised as 'CIAH', those with known diabetes as 'recognised diabetes', and those with HbA1c ≥6.5% but no previous diagnosis of diabetes as 'unrecognised diabetes'. The remainder were classified as 'normoglycaemic'. Hospital mortality, HbA1c and acute peak glycaemia were assessed using a logistic regression model.

RESULTS

Of 1,000 patients, 498 (49.8%) had CIAH, 220 (22%) had recognised diabetes, 55 (5.5%) had unrecognised diabetes and 227 (22.7%) were normoglycaemic. The risk of death increased by approximately 20% for each increase in acute glycaemia of 1 mmol/l in patients with CIAH and those with diabetes and HbA1c levels <7% (53 mmol/mol), but not in patients with diabetes and HbA1c ≥7%. This association was lost when adjusted for severity of illness.

CONCLUSIONS

Critical illness-associated hyperglycaemia is the most frequent cause of hyperglycaemia in the critically ill. Peak glucose concentrations during critical illness are associated with increased mortality in patients with adequate premorbid glycaemic control, but not in patients with premorbid hyperglycaemia. Optimal glucose thresholds in the critically ill may, therefore, be affected by premorbid glycaemia.

Glucagon-like peptide 1 attenuates the acceleration of gastric emptying induced by hypoglycemia in healthy subjects

OBJECTIVE

Exogenous GLP-1 slows gastric emptying in health and diabetes leading to diminished glycemic excursions. Gastric emptying is markedly accelerated by hypoglycemia. The primary objective was to determine whether GLP-1 attenuates the acceleration of gastric emptying induced by hypoglycemia.

RESEARCH DESIGN AND METHODS

Ten healthy volunteers were studied on four separate days in a randomized double-blind fashion. Blood glucose was stabilized using a glucose/insulin clamp at hypoglycemia (2.6 mmol/L on two occasions [hypo]) or euglycemia (6.0 mmol/L on two occasions [eu]) between T = -15 and 45 min before clamping at 6.0 mmol/L until 180 min. During hypoglycemia and euglycemia, subjects received intravenous GLP-1 (1.2 pmol/kg/min) or placebo. At T = 0 min, subjects ingested 100 g beef mince labeled with 20 MBq (99m)Tc-sulfur-colloid and 3 g of 3-O-methyl-glucose (3-OMG), a marker of glucose absorption. Gastric emptying was measured scintigraphically from T = 0 to 180 min and serum 3-OMG taken at 15-min intervals. The areas under the curve for gastric emptying and 3-OMG concentration were analyzed using one-way repeated-measures ANOVA with Bonferroni-Holm adjusted post hoc tests.

RESULTS

Gastric emptying was accelerated during hypoglycemia (hypo/placebo vs. eu/placebo; P < 0.001), as was glucose absorption (P < 0.03). GLP-1 slowed emptying during euglycemia (eu/placebo vs. eu/GLP-1; P < 0.001). However, hypoglycemia-induced acceleration of gastric emptying on placebo was markedly diminished by GLP-1 (hypo/placebo vs. hypo/GLP-1; P < 0.008), as was glucose absorption (P < 0.01).

CONCLUSIONS

Acute administration of exogenous GLP-1 attenuates, but does not abolish, the acceleration of gastric emptying by insulin-induced hypoglycemia in healthy subjects.

Pharmacokinetics of tramadol after subcutaneous administration in a critically ill population and in a healthy cohort

Background

Tramadol is an atypical centrally acting analgesic agent available as both oral and parenteral preparations. For patients who are unable to take tramadol orally, the subcutaneous route of administration offers an easy alternative to intravenous or intramuscular routes. This study aimed to characterise the absorption pharmacokinetics of a single subcutaneous dose of tramadol in severely ill patients and in healthy subjects.

Methods/design

Blood samples (5 ml) taken at intervals from 2 minutes to 24 hours after a subcutaneous dose of tramadol (50 mg) in 15 patients (13 male, two female) and eight healthy male subjects were assayed using high performance liquid chromatography. Pharmacokinetic parameters were derived using a non-compartmental approach.

Results

There were no statistically significant differences between the two groups in the following parameters (mean ± SD): maximum venous concentration 0.44 ± 0.18 (patients) vs. 0.47 ± 0.13 (healthy volunteers) mcg/ml (p = 0.67); area under the plasma concentration-time curve 177 ± 109 (patients) vs. 175 ± 75 (healthy volunteers) mcg/ml*min (p = 0.96); time to maximum venous concentration 23.3 ± 2 (patients) vs. 20.6 ± 18.8 (healthy volunteers) minutes (p = 0.73) and mean residence time 463 ± 233 (patients) vs. 466 ± 224 (healthy volunteers) minutes (p = 0.97).

Conclusions

The similar time to maximum venous concentration and mean residence time suggest similar absorption rates between the two groups. These results indicate that the same dosing regimens for subcutaneous tramadol administration may therefore be used in both healthy subjects and severely ill patients.

Trial registration

ACTRN12611001018909

Effect of high-dose pitavastatin on glucose homeostasis in patients at elevated risk of new-onset diabetes: insights from the CAPITAIN and PREVAIL-US studies

AIMS

Statin treatment may impair glucose homeostasis and increase the risk of new-onset diabetes mellitus, although this may depend on the statin, dose and patient population. We evaluated the effects of pitavastatin 4 mg/day on glucose homeostasis in patients with metabolic syndrome in the CAPITAIN trial. Findings were validated in a subset of patients enrolled in PREVAIL-US.

METHODS

Participants with a well defined metabolic syndrome phenotype were recruited to CAPITAIN to reduce the influence of confounding factors. Validation and comparison datasets were selected comprising phenotypically similar subsets of individuals enrolled in PREVAIL-US and treated with pitavastatin or pravastatin, respectively. Mean change from baseline in parameters of glucose homeostasis (fasting plasma glucose [FPG], glycated hemoglobin [HbA1c], insulin, quantitative insulin-sensitivity check index [QUICKI] and homeostasis model of assessment-insulin resistance [HOMA-IR]) and plasma lipid profile were assessed at 6 months (CAPITAIN) and 3 months (PREVAIL-US) after initiating treatment.

RESULTS

In CAPITAIN (n = 12), no significant differences from baseline in HbA1c, insulin, HOMA-IR and QUICKI were observed at day 180 in patients treated with pitavastatin. A small (4%) increase in FPG from baseline to day 180 (P < 0.05), was observed. In the validation dataset (n = 9), no significant differences from baseline in glycemic parameters were observed at day 84 (all comparisons P > 0.05). Similar results were observed for pravastatin in the comparison dataset (n = 14).

CONCLUSIONS

Other than a small change in FPG in the CAPITAIN study, neutral effects of pitavastatin on glucose homeostasis were observed in two cohorts of patients with metabolic syndrome, independent of its efficacy in reducing levels of atherogenic lipoproteins. The small number of patients and relatively short follow-up period represent limitations of the study. Nevertheless, these data suggest that statin-induced diabetogenesis may not represent a class effect.

An overview of the new frontiers in the treatment of atherogenic dyslipidemias

Cardiovascular diseases (CVDs) are the leading cause of morbidity/mortality worldwide. Dyslipidemia is a major risk factor for premature atherosclerosis and CVD. Lowering low-density-lipoprotein cholesterol (LDL-C) levels is well established as an intervention for the reduction of CVDs. Statins are the first-line drugs for treatment of dyslipidemia, but they do not address all CVD risk. Development of novel therapies is ongoing and includes the following: (i) reduction of LDL-C concentrations using antibodies to proprotein convertase subtilisin/kexin-9, antisense oligonucleotide inhibitors of apolipoprotein B production, microsomal transfer protein (MTP) inhibitors, and acyl-coenzyme A cholesterol acyl transferase inhibitors; (ii) reduction in levels of triglyceride-rich lipoproteins with ω-3 fatty acids, MTP inhibitors, and diacylglycerol acyl transferase-1 inhibitors; and (iii) increase of high-density-lipoprotein (HDL) cholesterol levels, HDL particle numbers, and/or HDL functionality using cholesteryl ester transfer protein inhibitors, HDL-derived agents, apolipoprotein AI mimetic peptides, and microRNAs. Large prospective outcome trials of several of these emerging therapies are under way, and thrilling progress in the field of lipid management is anticipated.

Incretins and the intensivist: what are they and what does an intensivist need to know about them?

Hyperglycaemia occurs frequently in the critically ill, even in those patients without a history of diabetes. The mechanisms underlying hyperglycaemia in this group are complex and incompletely defined. In health, the gastrointestinal tract is an important modulator of postprandial glycaemic excursions and both the rate of gastric emptying and the so-called incretin hormones, glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide, are pivotal determinants of postprandial glycaemia. Incretin-based therapies (that is, glucagon-like peptide- 1 agonists and dipeptidyl-peptidase-4 inhibitors) have recently been incorporated into standard algorithms for the management of hyperglycaemia in ambulant patients with type 2 diabetes and, inevitably, an increasing number of patients who were receiving these classes of drugs prior to their acute illness will present to ICUs. This paper summarises current knowledge of the incretin effect as well as the incretin-based therapies that are available for the management of type 2 diabetes, and provides suggestions for the potential relevance of these agents in the management of dysglycaemia in the critically ill, particularly to normalise elevated blood glucose levels.

Comparative effects of prolonged and intermittent stimulation of the glucagon-like peptide 1 receptor on gastric emptying and glycemia

Acute administration of glucagon-like peptide 1 (GLP-1) and its agonists slows gastric emptying, which represents the major mechanism underlying their attenuation of postprandial glycemic excursions. However, this effect may diminish during prolonged use. We compared the effects of prolonged and intermittent stimulation of the GLP-1 receptor on gastric emptying and glycemia. Ten healthy men received intravenous saline (placebo) or GLP-1 (0.8 pmol/kg ⋅ min), as a continuous 24-h infusion ("prolonged"), two 4.5-h infusions separated by 20 h ("intermittent"), and a 4.5-h infusion ("acute") in a randomized, double-blind, crossover fashion. Gastric emptying of a radiolabeled mashed potato meal was measured using scintigraphy. Acute GLP-1 markedly slowed gastric emptying. The magnitude of the slowing was attenuated with prolonged but maintained with intermittent infusions. GLP-1 potently diminished postprandial glycemia during acute and intermittent regimens. These observations suggest that short-acting GLP-1 agonists may be superior to long-acting agonists when aiming specifically to reduce postprandial glycemic excursions in the treatment of type 2 diabetes.

Endogenous amylin and glucagon-like peptide-1 concentrations are not associated with gastric emptying in critical illness

BACKGROUND

In health, the hormones amylin and glucagon-like peptide-1 (GLP-1) slow gastric emptying (GE) and modulate glycaemia. The aims of this study were to determine amylin and GLP-1 concentrations in the critically ill and their relationship with GE, glucose absorption and glycaemia.

METHODS

In fasted critically ill and healthy subjects (n = 26 and 23 respectively), liquid nutrient, containing 100 mg (13) C-sodium octanoate and 3 g 3-O-methlyglucose (3-OMG), was administered via a nasogastric tube. Amylin, GLP-1, glucose and 3-OMG concentrations were measured in blood samples taken during fasting, and 30 min and 60 min after the 'meal'. Breath samples were taken to determine gastric emptying coefficient (GEC). Intolerance to intragastric feeding was defined as a gastric residual volume of ≥ 250 ml and/or vomiting within the 24 h prior to the study.

RESULTS

Although GE was slower (GEC: critically ill 2.8 ± 0.9 vs. health, 3.4 ± 0.2; P = 0.002), fasting blood glucose was higher (7.0 ± 1.9 vs. 5.7 ± 0.2 mmol/l; P = 0.005) and overall glucose absorption was reduced in critically ill patients (3-OMG: 9.4 ± 8.0 vs. 17.7 ± 4.9 mmol/l.60 min; P < 0.001), there were no differences in fasting or postprandial amylin concentrations. Furthermore, although fasting [1.7 (0.4-7.2) vs. 0.7 (0.3-32.0) pmol/l; P = 0.04] and postprandial [3.0 (0.4-8.5) vs. 0.8 (0.4-34.3) pmol/l; P = 0.02] GLP-1 concentrations were increased in the critically ill and were greater in feed intolerant when compared with those tolerating feed [3.7 (0.4-7.2) vs. 1.2 (0.7-4.6) pmol/l; P = 0.02], there were no relationships between GE and fasting amylin or GLP-1 concentrations.

CONCLUSION

In the critically ill, fasting GLP-1, but not amylin, concentrations are elevated and associated with feed intolerance. Neither amylin nor GLP-1 appears to substantially influence the rate of GE.

The effects of critical illness on intestinal glucose sensing, transporters, and absorption

OBJECTIVES

Providing effective enteral nutrition is important during critical illness. In health, glucose is absorbed from the small intestine via sodium-dependent glucose transporter-1 and glucose transporter-2, which may both be regulated by intestinal sweet taste receptors. We evaluated the effect of critical illness on glucose absorption and expression of intestinal sodium-dependent glucose transporter-1, glucose transporter-2, and sweet taste receptors in humans and mice.

DESIGN

Prospective observational study in humans and mice.

SETTING

ICU and university-affiliated research laboratory.

SUBJECTS

Human subjects were 12 critically ill patients and 12 healthy controls. In the laboratory 16-week-old mice were studied.

INTERVENTIONS

Human subjects underwent endoscopy. Glucose (30 g) and 3-O-methylglucose (3 g), used to estimate glucose absorption, were infused intraduodenally over 30 minutes. Duodenal mucosa was biopsied before and after infusion. Mice were randomized to cecal ligation and puncture to model critical illness (n = 16) or sham laparotomy (control) (n = 8). At day 5, mice received glucose (100 mg) and 3-O-methylglucose (10 mg) infused intraduodenally prior to mucosal tissue collection.

MEASUREMENTS AND MAIN RESULTS

Quantitative polymerase chain reaction was performed to measure absolute (human) and relative levels of sodium-dependent glucose transporter-1, glucose transporter-2, and taste receptor type 1 member 2 (T1R2) transcripts. Blood samples were assayed for 3-O-methylglucose to estimate glucose absorption. Glucose absorption was three-fold lower in critically ill humans than in controls (p = 0.002) and reduced by a similar proportion in cecal ligation and puncture mice (p = 0.004). In critically ill patients, duodenal levels of sodium-dependent glucose transporter-1, glucose transporter-2, and T1R2 transcript were reduced 49% (p < 0.001), 50% (p = 0.009), and 85% (p = 0.007), whereas in the jejunum of cecal ligation and puncture mice sodium-dependent glucose transporter-1, glucose transporter-2, and T1R2 transcripts were reduced by 55% (p < 0.001), 50% (p = 0.002), and 69% (p = 0.004).

CONCLUSIONS

Critical illness is characterized by markedly diminished glucose absorption, associated with reduced intestinal expression of glucose transporters (sodium-dependent glucose transporter-1 and glucose transporter-2) and sweet taste receptor transcripts. These changes are paralleled in cecal ligation and puncture mice.

The effect of exogenous glucose-dependent insulinotropic polypeptide in combination with glucagon-like peptide-1 on glycemia in the critically ill

OBJECTIVE

Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) have additive insulinotropic effects when coadministered in health. We aimed to determine whether GIP confers additional glucose lowering to that of GLP-1 in the critically ill.

RESEARCH DESIGN AND METHODS

Twenty mechanically ventilated critically ill patients without known diabetes were studied in a prospective, randomized, double-blind, crossover fashion on 2 consecutive days. Between T0 and T420 minutes, GLP-1 (1.2 pmol/kg·min(-1)) was infused intravenously with either GIP (2 pmol/kg·min(-1)) or 0.9% saline. Between T60 and T420 minutes, nutrient liquid was infused into the small intestine at 1.5 kcal/min.

RESULTS

Adding GIP did not alter blood glucose or insulin responses to small intestinal nutrient. GIP increased glucagon concentrations slightly before nutrient delivery (P=0.03), but not thereafter.

CONCLUSIONS

The addition of GIP to GLP-1 does not result in additional glucose-lowering or insulinotropic effects in critically ill patients with acute-onset hyperglycemia.

Modulation of individual components of gastric motor response to duodenal glucose

AIM: To evaluate individual components of the antro-pyloro-duodenal (APD) motor response to graded small intestinal glucose infusions in healthy humans.

METHODS: APD manometry was performed in 15 healthy subjects (12 male; 40 ± 5 years, body mass index 26.5 ± 1.6 kg/m²) during four 20-min intraduodenal infusions of glucose at 0, 0.5, 1.0 and 1.5 kcal/min, in a randomised double-blinded fashion. Glucose solutions were infused at a rate of 1 mL/min and separated by 40-min “wash-out” period. Data are mean ± SE. Inferential analyses are repeated measure analysis of variance with Bonferroni post-hoc testing.

RESULTS: At 0 kcal/min frequency of pressure waves were: antrum (7.5 ± 1.8 waves/20 min) and isolated pyloric pressure waves (IPPWs) (8.0 ± 2.3 waves/20 min) with pyloric tone (0.0 ± 0.9 mmHg). Intraduodenal glucose infusion acutely increased IPPW frequency (P < 0.001) and pyloric tone (P = 0.015), and decreased antral wave frequency (P = 0.007) in a dose-dependent fashion. A threshold for stimulation was observed at 1.0 kcal/min for pyloric phasic pressure waves (P = 0.002) and 1.5 kcal/min for pyloric tone and antral contractility.

CONCLUSION: There is hierarchy for the activation of gastrointestinal motor responses to duodenal glucose infusion. An increase in IPPWs is the first response observed.

Gastrointestinal dysmotility: evidence and clinical management

PURPOSE OF REVIEW

Gastrointestinal dysmotility and dysfunction underlie our difficulties in providing adequate nutrition by the enteral route to our critically ill patients.

RECENT FINDINGS

Recent studies have quantified gastric emptying and nutrient absorption. Slow gastric emptying is common and probably mediated by cholecystokinin and reduced active ghrelin concentrations. The cause of impaired nutrient absorption is not yet fully understood but may be related to small intestinal blood flow and/or mucosal factors. The absorption of the different macronutrients may be affected in different ways both by critical illness and by therapies. A better understanding of this may optimize the design of nutrient formulations in the future. New treatment modalities for gastrointestinal dysfunction are being investigated and include small intestinal feeding, nonpharmacological options such as acupuncture, and drugs including novel motilin receptor agonists, and opioid antagonists.

SUMMARY

We are gradually developing a better understanding of how the gut works during critical illness, which has implications for optimizing the delivery of nutrition and thereby improving nutritional and clinical outcomes.

Mesenteric blood flow, glucose absorption and blood pressure responses to small intestinal glucose in critically ill patients older than 65 years

PURPOSE

To compare nutrient-stimulated changes in superior mesenteric artery (SMA) blood flow, glucose absorption and glycaemia in individuals older than 65 years with, and without, critical illness.

METHODS

Following a 1-h 'observation' period (t (0)-t (60)), 0.9 % saline and glucose (1 kcal/ml) were infused directly into the small intestine at 2 ml/min between t (60)-t (120), and t (120)-t (180), respectively. SMA blood flow was measured using Doppler ultrasonography at t (60) (fasting), t (90) and t (150) and is presented as raw values and nutrient-stimulated increment from baseline (Δ). Glucose absorption was evaluated using serum 3-O-methylglucose (3-OMG) concentrations during, and for 1 h after, the glucose infusion (i.e. t (120)-t (180) and t (120)-t (240)). Mean arterial pressure was recorded between t (60)-t (240). Data are presented as median (25th, 75th percentile).

RESULTS

Eleven mechanically ventilated critically ill patients [age 75 (69, 79) years] and nine healthy volunteers [70 (68, 77) years] were studied. The magnitude of the nutrient-stimulated increase in SMA flow was markedly less in the critically ill when compared with healthy subjects [Δt (150): patients 115 (-138, 367) versus health 836 (618, 1,054) ml/min; P = 0.001]. In patients, glucose absorption was reduced during, and for 1 h after, the glucose infusion when compared with health [AUC(120-180): 4.571 (2.591, 6.551) versus 11.307 (8.447, 14.167) mmol/l min; P < 0.001 and AUC(120-240): 26.5 (17.7, 35.3) versus 40.6 (31.7, 49.4) mmol/l min; P = 0.031]. A close relationship between the nutrient-stimulated increment in SMA flow and glucose absorption was evident (3-OMG AUC(120-180) and ∆SMA flow at t (150): r (2) = 0.29; P < 0.05).

CONCLUSIONS

In critically ill patients aged >65 years, stimulation of SMA flow by small intestinal glucose infusion may be attenuated, which could account for the reduction in glucose absorption.

Comparative effects on glucose absorption of intragastric and post-pyloric nutrient delivery in the critically ill

INTRODUCTION

Studies in the critically ill that evaluate intragastric and post-pyloric delivery of nutrient have yielded conflicting data. A limitation of these studies is that the influence in the route of feeding on glucose absorption and glycaemia has not been determined.

METHODS

In 68 mechanically ventilated critically ill patients, liquid nutrient (100 ml; 1 kcal/ml containing 3 g of 3-O-Methyl-D-glucopyranose (3-OMG), as a marker of glucose absorption), was infused into either the stomach (n = 24) or small intestine (n = 44) over six minutes. Blood glucose and serum 3-OMG concentrations were measured at regular intervals for 240 minutes and the area under the curves (AUCs) calculated for 'early' (AUC60) and 'overall' (AUC240) time periods. Data are presented as mean (95% confidence intervals).

RESULTS

Glucose absorption was initially more rapid following post-pyloric, when compared with intragastric, feeding (3-OMG AUC60: intragastric 7.3 (4.3, 10.2) vs. post-pyloric 12.5 (10.1, 14.8) mmol/l.min; P = 0.008); however, 'overall' glucose absorption was similar (AUC240: 49.1 (34.8, 63.5) vs. 56.6 (48.9, 64.3) mmol/l.min; P = 0.31). Post-pyloric administration of nutrients was also associated with greater increases in blood glucose concentrations in the 'early' period (AUC60: 472 (425, 519) vs. 534 (501, 569) mmol/l.min; P = 0.03), but 'overall' glycaemia was also similar (AUC240: 1,875 (1,674, 2,075) vs. 1,898 (1,755, 2,041) mmol/l.min; P = 0.85).

CONCLUSIONS

In the critically ill, glucose absorption was similar whether nutrient was administered via a gastric or post-pyloric catheter. These data may have implications for the perceived benefit of post-pyloric feeding on nutritional outcomes and warrant further investigation.

Enteral nutrition in Australian and New Zealand intensive care units: a point-prevalence study of prescription practices

BACKGROUND

Enteral nutrition (EN) is widely accepted as the preferred method for providing nutrition therapy to critically ill patients. However, optimal energy goals and the best way to achieve those goals are ill defined.

OBJECTIVE

To determine the type and energy concentration of commonly prescribed EN formulations and whether energy-dense formulations (> 1 kcal/mL) are used.

DESIGN

Prospective, observational, multicentre, single-day, point-prevalence study.

PARTICIPANTS AND SETTING

All patients present in 38 Australian and New Zealand intensive care units at 10:00 on 17 November 2010.

MAIN OUTCOME MEASURES

Demographic data, admission diagnosis and information on EN administration were collected.

RESULTS

522 patients were enrolled. Mean age was 58.7 (SD, 17.3) years, 65% were male and 79% were mechanically ventilated. On study day, 220/522 patients received EN (43%; 95% CI, 39%-48%). ICU admission source, Acute Physiology and Chronic Health Evaluation (APACHE) III diagnostic category, APACHE II score and ventilation on study day predicted receipt of EN. Of those receiving EN, 111/220 (51%; 95% CI, 44%-57%) received a 1 kcal/mL formulation and the remainder received an energy-dense formulation - 2 kcal/mL, 39/220 (18%; 95% CI, 13%-23%); and 1.5 kcal/mL, 32/220 (15%; 95% CI, 10%-20%). There were no significant predictors for receipt of energy-dense versus 1 kcal/mL EN.

CONCLUSIONS

1 kcal/mL and energy-dense formulations are administered with about equal frequency in Australian and New Zealand ICUs. This finding supports future research into the evaluation of optimal nutritional delivery amounts using EN formulations with differing energy concentrations.

Randomized double-blind crossover study to determine the effects of erythromycin on small intestinal nutrient absorption and transit in the critically ill

BACKGROUND

The gastrokinetic drug erythromycin is commonly administered to critically ill patients during intragastric feeding to augment small intestinal nutrient delivery. However, erythromycin has been reported to increase the prevalence of diarrhea, which may reflect reduced absorption and/or accelerated small intestinal transit.

OBJECTIVE

The objective was to evaluate the effects of intravenous erythromycin on small intestinal nutrient absorption and transit in the critically ill.

DESIGN

On consecutive days, erythromycin (200 mg in 20 mL 0.9% saline) or placebo (20 mL 0.9% saline) were infused intravenously between -20 and 0 min in a randomized, blinded, crossover fashion. Between 0 and 30 min, a liquid nutrient containing 3-O-methylglucose (3-OMG), [13C]triolein, and [(99m)Tc]sulfur colloid was administered directly into the small intestine at 2 kcal/min. Serum 3-OMG concentrations and exhaled (13)CO2 (indices of glucose and lipid absorption, respectively) were measured. Cecal arrival of the infused nutrient was determined by scintigraphy. Data are medians (ranges) and were analyzed by using Wilcoxon's signed-rank test.

RESULTS

Thirty-two mechanically ventilated patients were studied. Erythromycin increased small intestinal glucose absorption [3-OMG AUC360: 105.2 (28.9-157.0) for erythromycin compared with 91.8 (51.4-147.9) mmol/L · min for placebo; P = 0.029] but tended to reduce lipid absorption [cumulative percentage dose (13)CO2 recovered: 10.4 (0-90.6) compared with 22.6 (0-100) %; P = 0.06]. A trend to slower transit was observed after erythromycin [300 (39-360) compared with 228 (33-360) min; P = 0.07].

CONCLUSIONS

Acute administration of erythromycin increases small intestinal glucose absorption in the critically ill, but there was a tendency for the drug to reduce small intestinal lipid absorption and slow transit. These observations have implications for the use of erythromycin as a gastrokinetic drug in the critically ill. This trial was registered in the Australian New Zealand Clinical Trials Registry as ACTRN 12610000615088.

Pharmacokinetics of oxycodone after subcutaneous administration in a critically ill population compared with a healthy cohort

This study aimed to characterise and compare the absorption pharmacokinetics of a single subcutaneous dose of oxycodone in critically ill patients and healthy subjects. Blood samples taken at intervals from two minutes to eight hours after a subcutaneous dose of oxycodone in patients (5 mg) and healthy volunteers (10 mg) were assayed using high performance liquid chromatography. Data were analysed using a non-compartmental approach and presented as mean (SD). Parameters were corrected for dose differences between the groups assuming linear kinetics. Ten patients (eight male, two female) and seven healthy male subjects were included. Maximum venous concentration and area under the concentration curve were approximately two-fold lower in the patient group for an equivalent dose, suggesting either reduced bioavailability or increased clearance: maximum venous concentration 0.14 ± 0.06 vs 0.05 ± 0.02 µg/ml (P <0.0001); area under the concentration curve 19.50 ± 9.15 vs 9.72 ± 2.71 µg/ml/minute (P <0.001) respectively. However, time to maximum venous concentration and mean residence time were not different, suggesting similar absorption rates: time to maximum venous concentration 22.10 ± 18.0 vs 20.50 ± 16.10 minutes (P=0.81); mean residence time 353 ± 191 vs 291 ± 80 minutes (P=0.26). Kinetic parameters were less variable in patients than in volunteers. The patients therefore had reduced exposure to subcutaneous oxycodone. This warrants further model-based analysis and experimentation. Dose regimens for subcutaneous oxycodone developed in healthy volunteers cannot be directly translated to critically ill patients.

Nutrition and functional outcomes after critical illness due to pandemic (H1N1) 2009 influenza: a retrospective cohort study

OBJECTIVE

To determine functional outcomes 6 months after intensive care unit admission for severe infection due to pandemic (H1N1) 2009 influenza and examine the relationship between nutrition during ICU admission and outcome.

DESIGN, SETTING AND PARTICIPANTS

Retrospective cohort study of patients with confirmed H1N1 influenza admitted to the ICU, Royal Adelaide Hospital, South Australia, June- October 2009.

MAIN OUTCOME MEASURES

Data were collected from medical records, dietitian notes and the daily ICU chart and included: demographics, daily kilocalories (Kcal) and protein delivered compared with dietitian-calculated requirement, ICU and hospital length of stay. Weight change and functional outcome at 6 months were determined prospectively by telephone interview using the 12-Item Short Form Health Survey and the EuroQol Group 5-Dimension Questionnaire.

RESULTS

Of 25 patients with H1N1 infection, 23 were included in the study (14 men; median age, 48 years (interquartile range [IQR], 39-55 years); median Acute Physiology and Chronic Health Evaluation (APACHE) II score, 17 (IQR, 13-21); median ICU length of stay, 9 days (IQR, 4-15 days); median hospital length of stay, 20 days (IQR, 11-30 days); ICU mortality, 3 (13%; 95% CI, 4%- 33%). Enteral feeding was commenced in 16 patients, who received a mean of 71% (SD, 27%; 95% CI, 57%-86%) of their energy and 62% (SD, 25%; 95% CI, 49%-75%) of their protein goals over their ICU stay. A more negative protein balance was associated with prolonged ICU stay (r = - 0.746; P = 0.003). Reduced success of feeding was associated with increased severity of illness and shorter ICU length of stay. Patients reported a good functional outcome at 6 months.

CONCLUSIONS

Patients admitted to this ICU with H1N1 infection were fed successfully during their stay. Critically ill patients surviving H1N1 infection had good functional outcomes at 6 months.

Gastrointestinal dysmotility: clinical consequences and management of the critically ill patient

Gastrointestinal dysmotility is a common feature of critical illness, with a number of significant implications that include malnutrition secondary to reduced feed tolerance and absorption, reflux and aspiration resulting in reduced lung function and ventilator-associated pneumonia, bacterial overgrowth and possible translocation causing nosocomial sepsis. Prokinetic agent administration can improve gastric emptying and caloric delivery, but its effect on nutrient absorption and clinical outcomes is, as yet, unclear. Postpyloric delivery of nutrition has not yet been demonstrated to increase caloric intake or improve clinical outcomes.

Serum levels of adhesion molecules ICAM-1 and VCAM-1 and tissue inhibitor of metalloproteinases, TIMP-1, are elevated in patients with autoimmune thyroid disorders: relevance to vascular inflammation

Serum levels of ICAM-1 (Inter Cellular Adhesion Molecule-1), VCAM-1 (Vascular cell Adhesion Molecule-1-I), TIMP-1 (tissue inhibitor of metalloproteinases 1) and MMP-9 (Metalloproteinase 9) are well established markers of inflammation. The physiopathological link between inflammation, atherosclerosis and autoimmunity is well demonstrated. However, serum levels of these biomarkers in patients with autoimmune-mediated dysthyroidism, including their evolution after improvement of the thyroid disorder have not been assessed. So, we evaluated the circulating levels of these markers in autoimmune and in non-autoimmune-mediated dysthyroid patients, and their evolution after treatment of thyroid disease. We conducted a prospective study to evaluate these markers before and after treatment in hyperthyroid patients (n = 33; 28 patients with autoimmune disease), hypothyroid patients (n = 38; 33 patients with autoimmune disease) and euthyroid subjects (n = 33). At baseline, serum levels of ICAM-1, VCAM-1 and TIMP-1 were significantly elevated in patients with hyperthyroidism as compared to euthyroid and hypothyroid patients (respectively p = 0.0005 and p < 0.0001). In multivariate analysis, the differences remained significant for VCAM-1 and TIMP-1. Median levels of ICAM-1, VCAM-1 and TIMP-1 were significantly higher in patients with autoimmune-mediated dysthyroidism compared to euthyroid patients (respectively p < 0.0001 and p = 0.002). In hyperthyroid patients, ICAM-1, VCAM-1 and TIMP-1 concentrations fell significantly after they had become euthyroid (respectively p = 0.0006; p < 0.0001 and p = 0.0009), although VCAM-1 values remained higher than those observed in the control group (p = 0.005). We found that autoimmune-mediated dysthyroidism were associated with increased peripheral blood concentrations of VCAM-1, ICAM-1 and TIMP-1. Whether these biological abnormalities translate into increase intima remodelling and atherosclerosis remains to be studied.

Gastric emptying of a liquid nutrient meal in the critically ill: relationship between scintigraphic and carbon breath test measurement

OBJECTIVE

It is assumed that delayed gastric emptying (GE) occurs frequently in critical illness; however, the prevalence of slow GE has not previously been assessed using scintigraphy. Furthermore, breath tests could potentially provide a convenient method of quantifying GE, but have not been validated in this setting. The aims of this study were to (i) determine the prevalence of delayed GE in unselected, critically ill patients and (ii) evaluate the relationships between GE as measured by scintigraphy and carbon breath test.

DESIGN

Prospective observational study.

SETTING

Mixed medical/surgical intensive care unit.

PATIENTS

25 unselected, mechanically ventilated patients (age 66 years (49-72); and 14 healthy subjects (age 62 years (19-84)).

INTERVENTIONS

GE was measured using scintigraphy and (14)C-breath test. A test meal of 100 ml Ensure (standard liquid feed) labelled with (14)C octanoic acid and (99m)Technetium sulphur colloid was placed in the stomach via a nasogastric tube.

MAIN OUTCOME MEASURES

Gastric 'meal' retention (scintigraphy) at 60, 120, 180 and 240 min, breath test t(50) (BTt(50)), and GE coefficient were determined.

RESULTS

Of the 24 patients with scintigraphic data, GE was delayed at 120 min in 12 (50%). Breath tests correlated well with scintigraphy in both patients and healthy subjects (% retention at 120 min vs BTt(50); r(2)=0.57 healthy; r(2)=0.56 patients; p≤0.002 for both).

CONCLUSIONS

GE of liquid nutrient is delayed in approximately 50% of critically ill patients. Breath tests correlate well with scintigraphy and are a valid method of GE measurement in this group.

Glucose absorption and small intestinal transit in critical illness

OBJECTIVES

Although enteral nutrition is standard care for critically ill patients, nutrient absorption has not been quantified in this group and may be impaired due to intestinal dysmotility. The objectives of this study were to measure small intestinal glucose absorption and duodenocecal transit and determine their relationship with glycemia in the critically ill.

DESIGN

Prospective observational study of healthy and critically ill subjects.

SETTING

Tertiary mixed medical-surgical adult intensive care unit.

SUBJECTS

Twenty-eight critically ill patients and 16 healthy subjects were studied. MATERIALS AND MAIN RESULTS: Liquid feed (100 kcal/100 mL), labeled with Tc-sulfur colloid and including 3 g of 3-O-methylglucose, was infused into the duodenum. Glucose absorption and duodenocecal transit were measured using the area under the 3-O-methylglucose concentration curve and scintigraphy, respectively. Data are median (range).

RESULTS AND DISCUSSION

Glucose absorption was reduced in critical illness when compared to health (area under the concentration curve: 16 [1-32] vs. 20 [14-34] mmol/L·min; p = .03). Small intestinal transit times were comparable in patients and healthy subjects (192 [9-240] vs. 168 [6-240] min; p = .99) and were not related to glucose absorption. Despite higher fasting blood glucose concentrations (6.3 [5.1-9.3] vs. 5.7 [4.6-7.6] mmol/L; p < .05), the increment in blood glucose was sustained for longer in the critically ill (Δ glucose at t = 60; 1.9 [-2.1-5.0] mmol/L vs. -0.2 [-1.3-2.3] mmol/L; p < .01).

CONCLUSIONS

Critical illness is associated with reduced small intestinal glucose absorption, but despite this, the glycemic response to enteral nutrient is sustained for longer.

Exogenous glucagon-like peptide-1 attenuates the glycaemic response to postpyloric nutrient infusion in critically ill patients with type-2 diabetes

INTRODUCTION

Glucagon-like peptide-1 (GLP-1) attenuates the glycaemic response to small intestinal nutrient infusion in stress-induced hyperglycaemia and reduces fasting glucose concentrations in critically ill patients with type-2 diabetes. The objective of this study was to evaluate the effects of acute administration of GLP-1 on the glycaemic response to small intestinal nutrient infusion in critically ill patients with pre-existing type-2 diabetes.

METHODS

Eleven critically ill mechanically-ventilated patients with known type-2 diabetes received intravenous infusions of GLP-1 (1.2 pmol/kg/minute) and placebo from t = 0 to 270 minutes on separate days in randomised double-blind fashion. Between t = 30 to 270 minutes a liquid nutrient was infused intraduodenally at a rate of 1 kcal/min via a naso-enteric catheter. Blood glucose, serum insulin and C-peptide, and plasma glucagon were measured. Data are mean ± SEM.

RESULTS

GLP-1 attenuated the overall glycaemic response to nutrient (blood glucose AUC30-270 min: GLP-1 2,244 ± 184 vs. placebo 2,679 ± 233 mmol/l/minute; P = 0.02). Blood glucose was maintained at < 10 mmol/l in 6/11 patients when receiving GLP-1 and 4/11 with placebo. GLP-1 increased serum insulin at 270 minutes (GLP-1: 23.4 ± 6.7 vs. placebo: 16.4 ± 5.5 mU/l; P < 0.05), but had no effect on the change in plasma glucagon.

CONCLUSIONS

Exogenous GLP-1 in a dose of 1.2 pmol/kg/minute attenuates the glycaemic response to small intestinal nutrient in critically ill patients with type-2 diabetes. Given the modest magnitude of the reduction in glycaemia the effects of GLP-1 at higher doses and/or when administered in combination with insulin, warrant evaluation in this group.

TRIAL REGISTRATION

ANZCTR:ACTRN12610000185066.

Intrasubject variability of gastric emptying in the critically ill using a stable isotope breath test

BACKGROUND AND AIMS

Isotope breath tests are increasingly used to evaluate the effects of prokinetic drugs on gastric emptying. The aim was to assess intrasubject variability in gastric emptying, when using an isotope breath test in the critically ill.

METHODS

A retrospective analysis of data was undertaken in 12 patients who had gastric emptying measurements on consecutive days using a (13)C-octanoic acid breath test. The gastric emptying coefficient--GEC (a global index for the gastric emptying rate), and the t(50) (calculated time for 50% of meal to empty) were calculated, together with the coefficient of variability for these parameters. Data are mean (SD).

RESULTS

Neither GEC (day 1: 3.3 (0.8) vs. day 2: 3.1 (0.6); P = 0.31) nor t(50) (day 1: 127 (43) min vs. day 2: 141 (48) min; P = 0.46) were significantly different between the two days. Intrasubject variability was less for GEC (15.6%) than for t(50) (31.8%).

CONCLUSION

There is only modest intrasubject variability in GEC measurements using the (13)C-octanoic acid breath test in critically ill patients. As such, it may be an acceptable measurement tool to assess the effects of prokinetic drugs in this group.

Enteral nutrition for patients in septic shock: a retrospective cohort study

BACKGROUND

Haemodynamic instability is frequently considered a contraindication to enteral feeding. However, gastrointestinal function and the success of enteral feeding have never been formally examined in patients with shock.

OBJECTIVE

To assess the adequacy of enteral nutrition in mechanically ventilated septic patients with and without shock.

DESIGN, SETTING AND PARTICIPANTS

Retrospective cohort study of septic patients receiving enteral nutrition in the intensive care unit of the Royal Adelaide Hospital in 2006. Patient data were obtained from case notes, nursing charts and dietitian notes. Enteral feeding was reviewed over a 7-day period in septic patients who were ventilated on more than 3 days. Adequacy of nutrition was defined as net calories delivered (including propofol) as a percentage of goal calories prescribed.

MEAN OUTCOME MEASURES

Mean time to initiation of feeds; percentage of nutritional goals reached.

RESULTS

43 patients (mean age, 54 [SD, 20] years; mean APACHE II score, 20 [SD, 8]) were identified, of whom 33 had shock. The median length of ICU stay was 13 days (range, 3-55 days), and 32 patients (74%) survived hospital. Seventeen patients (40%) received <60% of goal nutrition over the 7 days. Overall calorie delivery improved over time and peaked at 86% of goal calories by Day 6. The mean time from ICU admission to start of feeding was 1.4 (range, 0-8) days. The mean time to initiation of feeding was not different in patients with or without shock: 1.3 (SD, 1.7) days v 1.7 (SD, 1.3) days (P=0.16). Patients with shock had higher mean daily gastric aspirate volumes than those without (113 [SD, 153] mL v 39 [SD, 47] mL; P=0.02), but no difference was found in the percentage of their nutritional goals reached (69% [SD, 23%] v 77% [SD, 16%]; P=0.2).

CONCLUSION

Despite delayed gastric emptying, protocoldirected enteral feeding can be considered in patients with septic shock.

Characteristics of plasma NOx levels in severe sepsis: high interindividual variability and correlation with illness severity, but lack of correlation with cortisol levels

Objectives Nitric oxide (NO) concentrations are elevated in sepsis and their vasodilatory action may contribute to the development of hyperdynamic circulatory failure. Hydrocortisone infusion has been reported to reduce nitric oxide metabolite (NOx) concentrations and facilitate vasopressor withdrawal in septic shock. Our aim was to determine whether NOx concentrations relate to (i) protocol-driven vasopressor initiation and withdrawal and (ii) plasma cortisol concentrations, from endogenous and exogenous sources. Demonstration of a relation between NOx, cortisol and vasopressor requirement may provide an impetus towards the study of hydrocortisone-mediated NOx suppression as a tool in sepsis management. Design A prospective study of 62 patients with severe sepsis admitted to the intensive care unit. Measurements Plasma NOx, total and free cortisol, and corticosteroid-binding globulin (CBG) concentrations were measured and related to protocol-driven vasopressor use for 7 days following admission. Results Patients who developed septic shock (n = 35) had higher plasma NOx, total and free cortisol, and lower CBG concentrations than the nonseptic shock group (n = 27). Cortisol, CBG and NOx concentrations correlated with illness severity. Free cortisol, and to a lesser extent total cortisol, but not NOx concentrations, predicted septic shock. NOx concentrations were higher in nonsurvivors, and the concentrations were characteristically stable within individuals but marked interindividual differences were only partly accounted for by illness severity or renal dysfunction. NOx concentrations did not correlate with cortisol, did not relate to vasopressor requirement and did not fall after standard dose hydrocortisone, given for clinical indications. Conclusions Nitric oxide production increased with sepsis severity but did not correlate with plasma cortisol or vasopressor requirement. NOx levels were not suppressed reproducibly by hydrocortisone. High interindividual variability of NOx levels suggests that absolute NOx levels may not be a suitable target for individualized hydrocortisone therapy.

Effects of exogenous glucagon-like peptide-1 on gastric emptying and glucose absorption in the critically ill: relationship to glycemia

OBJECTIVE

To determine the acute effects of exogenous glucagon-like peptide-1 on gastric emptying, glucose absorption, glycemia, plasma insulin, and glucagon in critically ill patients.

DESIGN

Randomized, double-blind, crossover study.

SETTING

Intensive care unit.

SUBJECTS

Twenty-five mechanically ventilated patients, without known diabetes, studied on consecutive days.

INTERVENTIONS

Intravenous glucagon-like peptide-1 (1.2 pmol/kg/min) or placebo was infused between -30 and 330 mins. At 0 min, 100 mL liquid nutrient (1 kcal/mL) including 100 microg of 13C-octanoic acid and 3 grams of 3-O-methyl-glucose was administered.

MEASUREMENTS AND MAIN RESULTS

Blood glucose, serum 3-O-methyl-glucose (as an index of glucose absorption), insulin and glucagon concentrations, as well as exhaled 13CO2 were measured. The gastric emptying coefficient was calculated to quantify gastric emptying. Data are presented as mean (sd). There was a nonsignificant trend for glucagon-like peptide-1 to slow gastric emptying (gastric emptying coefficient) (glucagon-like peptide-1, 2.45 [0.93] vs. placebo, 2.75 [0.83]; p = .09). In 11 of the 25 patients, gastric emptying was delayed during placebo infusion and glucagon-like peptide-1 had no detectable effect on gastric emptying in this group (1.92 [0.82] vs. 1.90 [0.68]; p = .96). In contrast, in patients who had normal gastric emptying during placebo, glucagon-like peptide-1 slowed gastric emptying substantially (2.86 [0.58] vs. 3.41 [0.37]; p = .006). Glucagon-like peptide-1 markedly reduced the rate of glucose absorption (3-O-methyl-glucose area under the curve(0-330), 37 [35] vs. 76 [51] mmol/L/min; p < .001), decreased preprandial glucagon (at 0 min change in glucagon, -15 [15] vs. -3 [14] pmol/L; p < .001), increased the insulin/glucose ratio throughout the infusion (area under the curve(-30-330), 1374 [814] vs. 1172 [649] mU/mmol/min; p = .041), and attenuated the glycemic response to the meal (glucose area under the curve(0-330), 2071 [353] vs. 2419 [594] mmol/L/min; p = .001).

CONCLUSIONS

Exogenous glucagon-like peptide-1 lowers postprandial glycemia in the critically ill. This may occur, at least in part, by slowing gastric emptying when the latter is normal but not when it is delayed.

Bench-to-bedside review: the gut as an endocrine organ in the critically ill

In health, hormones secreted from the gastrointestinal tract have an important role in regulating gastrointestinal motility, glucose metabolism and immune function. Recent studies in the critically ill have established that the secretion of a number of these hormones is abnormal, which probably contributes to disordered gastrointestinal and metabolic function. Furthermore, manipulation of endogenous secretion, physiological replacement and supra-physiological treatment (pharmacological dosing) of these hormones are likely to be novel therapeutic targets in this group. Fasting ghrelin concentrations are reduced in the early phase of critical illness, and exogenous ghrelin is a potential therapy that could be used to accelerate gastric emptying and/or stimulate appetite. Motilin agonists, such as erythromycin, are effective gastrokinetic drugs in the critically ill. Cholecystokinin and peptide YY concentrations are elevated in both the fasting and postprandial states, and are likely to contribute to slow gastric emptying. Accordingly, there is a rationale for the therapeutic use of their antagonists. So-called incretin therapies (glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide) warrant evaluation in the management of hyperglycaemia in the critically ill. Exogenous glucagon-like peptide-2 (or its analogues) may be a potential therapy because of its intestinotropic properties.

The therapeutic potential of a venomous lizard: the use of glucagon-like peptide-1 analogues in the critically ill

Glucagon-like peptide-1 (GLP-1), a principal mediator of the postprandial insulinotropic response in health, has a half-life of minutes. The saliva of the Gila monster contains exendin-4, a structural analogue of human GLP-1, but with a much longer half-life. A synthetic preparation of exendin-4, exenatide, is suitable for human use and effectively lowers glucose in ambulant type 2 diabetic patients. When compared with insulin, exenatide therapy is associated with a reduction in hypoglycaemic episodes and postprandial glycaemic excursions in this group. Accordingly, GLP-1 analogues are appealing therapies for hyperglycaemia in the critically ill patient and warrant further study.

Endogenous glucagon-like peptide-1 slows gastric emptying in healthy subjects, attenuating postprandial glycemia

INTRODUCTION

The role of glucagon-like peptide-1 (GLP-1) in the regulation of gastric emptying is uncertain. The aim of this study was to determine the effects of endogenous GLP-1 on gastric emptying, glucose absorption, and glycemia in health.

METHODS

Ten healthy fasted subjects (eight males, two females; 48 +/- 7 yr) received the specific GLP-1 antagonist, exendin(9-39) amide [ex(9-39)NH(2)] (300 pmol/kg x min iv), or placebo, between -30 and 180 min in a randomized, double-blind, crossover fashion. At 0 min, a mashed potato meal ( approximately 2600 kJ) containing 3 g 3-ortho-methyl-D-glucose (3-OMG) and labeled with 20 MBq (99m)Technetium-sulphur colloid was eaten. Gastric emptying, including the time taken for 50% of the meal to empty from the stomach (T50), blood glucose, plasma 3-OMG, and plasma insulin were measured.

RESULTS

Ex(9-39)NH(2) accelerated gastric emptying [T50 ex(9-39)NH(2), 68 +/- 8 min, vs. placebo, 83 +/- 7 min; P < 0.001] and increased the overall glycemic response to the meal [area under the curve (0-180 min) ex(9-39)NH(2), 1540 +/- 106 mmol/liter x min, vs. placebo, 1388 +/- 90 mmol/liter x min; P < 0.02]. At 60 min, ex(9-39)NH(2) increased the rise in glycemia [ex(9-39)NH(2), 9.9 +/- 0.5 mmol/liter, vs. placebo, 8.4 +/- 0.5 mmol/liter; P < 0.01], plasma 3-OMG [ex(9-39)NH(2), 0.25 +/- 0.01 mmol/liter, vs. placebo, 0.21 +/- 0.01 mmol/liter; P < 0.05], and plasma insulin [ex(9-39)NH(2), 82 +/- 13 mU/liter, vs. placebo, 59 +/- 9 mU/liter; P < 0.05] concentrations. There was a close within-subject correlation between glycemia and gastric emptying [e.g. at 60 min, the increment in blood glucose and gastric emptying (T50); r = -0.89; P < 0.001].

CONCLUSION

GLP-1 plays a physiological role to slow gastric emptying in health, which impacts on glucose absorption and, hence, postprandial glycemia.

Evaluation of a bedside technique for postpyloric placement of feeding catheters

OBJECTIVES

To establish the success rate, time taken and expertise required to place a feeding catheter into the small intestine using a device that permits real-time localisation of the catheter through detection of an electromagnetic field.

DESIGN

Prospective observational study.

SETTING

A tertiary, mixed medical-surgical, adult intensive care unit, between February 2008 and February 2009.

PARTICIPANTS

60 attempts at postpyloric intubation by eight clinicians (consultant and trainee intensivists and a dietitian) in 57 critically ill patients who were undergoing mechanical ventilation and were receiving, or suitable to receive, enteral nutrition.

MAIN OUTCOME MEASURES

Patients were classified into an initial group (10 patients), who had the catheter placed by a single clinician to establish the most effective technique, and a subsequent group (50 patients), who had the catheter placed by any of the eight clinicians. Catheter position was confirmed on abdominal x-ray by an independent radiologist.

RESULTS

Postpyloric catheter placement was successful in 56/60 attempts (93%), in 54/57 patients (95%), with a median time to placement of 7.2 min (interquartile range [IQR], 4.3-12.5 min). In the initial group, placement was successful in 7/10 attempts (70%), with a median time to placement of 20.8 min (IQR, 9.5-32.3 min), compared with 49/50 attempts (98%) and a median time of 5.9 min (IQR, 3.9-11.9 min) in the subsequent group (P = 0.003).

CONCLUSIONS

An electromagnetically guided device enabled reliable and rapid bedside placement of small intestinal feeding catheters. Proficiency with the technique was quickly developed and successfully disseminated to a range of clinicians.

Prokinetic drugs for feed intolerance in critical illness: current and potential therapies

Studies consistently show that nasogastric nutrition delivers only about 60% of nutritional goals in critically ill patients. The predominant reason is abnormal gastric motility, leading to delayed gastric emptying, which is evident clinically as large gastric residual volumes. Delayed gastric emptying occurs in about 50%-60% of critically ill patients who are fed enterally and can result in malnutrition. Furthermore, delayed gastric emptying may increase the risk of aspiration of gastric contents. Recent research has improved our understanding of the complex abnormalities of gastric motor function that underlie delayed gastric emptying in the critically ill. Feed intolerance can be treated with prokinetic drugs and/or by the placement of postpyloric feeding catheters. The place of prokinetic agents in the treatment of feed intolerance is as yet unclear, but current evidence supports the administration of erythromycin combined with metoclopramide as first-line therapy. Other novel drugs, such as methylnaltrexone, mitemcinal, ghrelin agonists and dexloxiglumide, have potential advantages over these agents but require further investigation before widespread clinical use.