Models of intensive care unit follow-up care and feasibility of intervention delivery: A systematic review.

BACKGROUND: The optimal model of outpatient intensive care unit (ICU) follow-up care remains uncertain, and there is limited evidence of benefit. RESEARCH QUESTION: The objective of this research is to describe existing models of outpatient ICU follow-up care, quantify participant recruitment and retention, and describe facilitators of patient engagement. STUDY DESIGN & METHODS: A systematic search of the MEDLINE and EMBASE databases was undertaken in June 2021. Two independent reviewers screened titles, abstracts, and full texts against eligibility criteria. Studies of adults with any outpatient ICU follow-up were included. Studies were excluded if published before 1990, not published in English, or of paediatric patients. Quantitative data were extracted using predefined data fields. Key themes were extracted from qualitative studies. Risk of bias was assessed. RESULTS: A total of 531 studies were screened. Forty-seven studies (32 quantitative and 15 qualitative studies) with a total of 5998 participants were included. Of 33 quantitative study interventions, the most frequently reported model of care was in-person hospital-based interventions (n = 27), with 10 hybrid (part in-hospital, part remote) interventions. Literature was limited for interventions without hospital attendance (n = 6), including telehealth and diaries. The median ranges of rates of recruitment, rates of intervention delivery, and retention to outcome assessment for hospital-based interventions were 51.5% [24-94%], 61.9% [8-100%], and 52% [8.1-82%], respectively. Rates were higher for interventions without hospital attendance: 82.6% [60-100%], 68.5% [59-89%], and 75% [54-100%]. Facilitators of engagement included patient-perceived value of follow-up, continuity of care, intervention accessibility and flexibility, and follow-up design. Studies had a moderate risk of bias. INTERPRETATION: Models of post-ICU care without in-person attendance at the index hospital potentially have higher rates of recruitment, intervention delivery success, and increased participant retention when compared to hospital-based interventions. PROSPERO REGISTRATION: CRD42021260279.

Relationship of blood thiamine pyrophosphate to plasma phosphate and the response to enteral nutrition plus co-administration of intravenous thiamine during critical illness.

BACKGROUND: Hypovitamin B1 occurs frequently during critical illness but is challenging to predict or rapidly diagnose. The aim of this study was to evaluate whether plasma phosphate concentrations predict hypovitamin B1, enteral nutrition prevents hypovitamin B1 and intravenous thiamine supplementation achieves supraphysiological concentrations in critically ill patients. METHODS: Thirty-two enterally fed critically ill patients, with a plasma phosphate concentration ≤0.65 mmol/L, formed a nested cohort within a larger randomised clinical trial. Patients were assigned to receive intravenous thiamine (200 mg) twice daily, and controls were not administered intravenous thiamine. Thiamine pyrophosphate concentrations were measured at four time points (pre- and post-infusion and 4- and 6-h post-infusion) on days 1 and 3 in those allocated to thiamine and once in the control group. RESULTS: Baseline thiamine pyrophosphate concentrations were similar (intervention 88 [67, 93] vs. control 89 [62, 110] nmol/L, p = 0.49). Eight (25%) patients had hypovitamin B1 (intervention 3 vs. control 5), with two patients in the control group remaining insufficient at day 3. There was no association between baseline phosphate and thiamine pyrophosphate concentrations. Intravenous thiamine achieved supraphysiological concentrations 6 h post first infusion, with concentrations increasing to day 3. In the control group, thiamine pyrophosphate concentrations were not statistically different between baseline and day 3 (mean change: 8.6 [-6.0, 23.1] nmol/L, p = 0.25). CONCLUSIONS: Phosphate concentrations did not predict hypovitamin B1, which was observed in 25% of the participants. Enteral nutrition alone prevented the development of new hypovitamin B1. Administration of a single 200-mg dose of intravenous thiamine achieved supraphysiological concentrations of thiamine pyrophosphate, with repeated dosing sustaining this effect.

Cerebrospinal fluid and plasma ascorbate concentrations following subarachnoid haemorrhage.

Background: Ascorbate, the biologically active form of vitamin C, is the primary neural anti-oxidant. Ascorbate concentrations have never been quantified following aneurysmal subarachnoid haemorrhage (aSAH). Objective: To quantify plasma and cerebrospinal fluid (CSF) ascorbate concentrations in patients following SAH. Design Setting Participants Main Outcome Measures: Cohort study in which plasma and CSF ascorbate concentrations were measured longitudinally in 12 aSAH patients admitted to a quaternary referral intensive care unit and compared to one-off samples obtained from 20 pregnant women prior to delivery in a co-located obstetric hospital. Data are median [interquartile range] or median (95 % confidence intervals). Results: Forty-eight plasma samples were obtained from the 12 aSAH patients (eight females, age 62 [53-68] years). Eight participants with extra-ventricular drains provided 31 paired CSF-plasma samples. Single plasma and CSF samples were obtained from 20 pregnant women (age 35 [31-37] years). Initial plasma and CSF ascorbate concentrations post aSAH were less than half those in pregnant controls (plasma: aSAH: 31 [25-39] µmol/L vs. comparator: 64 [59-77] µmol/L; P < 0.001 and CSF: 116 [80-142] µmol/L vs. 252 [240-288] µmol/L; P < 0.001). Post aSAH there was a gradual reduction in the CSF:plasma ascorbate ratio from ∼4:1 to ∼1:1. Six (50 %) patients developed vasospasm and CSF ascorbate concentrations were lower in these patients (vasospasm: 61 (25, 97) vs. no vasospasm: 110 (96, 125) µmol/L; P = 0.01). Conclusion: Post aSAH there is a marked reduction in CSF ascorbate concentration that is most prominent in those who develop vasospasm.

Communication with bereaved family members after death in the ICU: the CATHARTIC randomised clinical trial.

Objective: It is uncertain whether psychological distress in the family members of patients who die during an intensive care unit (ICU) admission may be improved by bereavement interventions. In this trial, relatives' symptoms of anxiety and depression after 6 months were measured when allocated to three commonly used bereavement follow-up strategies. Design: Single-centre, randomised, three parallel-group trial. Setting: A tertiary ICU in Australia. Participants: Relatives of patients who died in the ICU. Interventions: Relatives received bereavement follow-up 4 weeks after the death using a condolence letter, short telephone call or no contact. Main outcome measures: The primary outcome was the total Hospital Anxiety and Depression Scale (HADS-T) score. Secondary outcomes estimated anxiety, depression, complicated grief, post-traumatic stress, and satisfaction with ICU care. Results: Seventy-one relatives participated (24 had no contact, 19 were contacted by letter and 28 by telephone 4 weeks after the death). The mean HADS-T score for no contact was 16.1 (95% CI, 12.4-19.8). Receipt of a letter was associated with a mean HADS-T increase of 1.4 (4.0 decrease to 6.8 increase), and a condolence call was accompanied by a mean decrease of 1.6 (6.6 decrease to 3.4 increase; P > 0.5). Non-significant differences were observed for all secondary outcomes. Conclusions: Anxiety and depression at 6 months in the relatives of patients who died in the ICU was not meaningfully alleviated by receipt of either a condolence letter or telephone call. Trial registration: Australia New Zealand Clinical Trials Registry (ACTRN12619000917134).

Effects of Standard vs Energy-Dense Formulae on Gastric Retention, Energy Delivery, and Glycemia in Critically Ill Patients.

BACKGROUND: Energy-dense formulae are often provided to critically ill patients with enteral feed intolerance with the aim of increasing energy delivery, yet the effect on gastric emptying is unknown. The rate of gastric emptying of a standard compared with an energy-dense formula was quantified in critically ill patients. METHODS: Mechanically ventilated adults were randomized to receive radiolabeled intragastric infusions of 200 mL standard (1 kcal/mL) or 100 mL energy-dense (2 kcal/mL) enteral formulae on consecutive days in this noninferiority, blinded, crossover trial. The primary outcome was scintigraphic measurement of gastric retention (percentage at 120 minutes). Other measures included area under the curve (AUC) for gastric retention and intestinal energy delivery (calculated from gastric retention of formulae over time), blood glucose (peak and AUC), and intestinal glucose absorption (using 3-O-methyl-D-gluco-pyranose [3-OMG] concentrations). Comparisons were undertaken using paired mixed-effects models. Data presented are mean ± SE. RESULTS: Eighteen patients were studied (male/female, 14:4; age, 55.2 ± 5.3 years). Gastric retention at 120 minutes was greater with the energy-dense formula (standard, 17.0 ± 5.9 vs energy-dense, 32.5 ± 7.1; difference, 12.7% [90% confidence interval, 0.8%-30.1%]). Energy delivery (AUC120 , 13,038 ± 1119 vs 9763 ± 1346 kcal/120 minutes; P = 0.057), glucose control (peak glucose, 10.1 ± 0.3 vs 9.7 ± 0.3 mmol/L, P = 0.362; and glucose AUC120 8.7 ± 0.3 vs 8.5 ± 0.3 mmol/L.120 minutes, P = 0.661), and absorption (3-OMG AUC120 , 38.5 ± 4.0 vs 35.7 ± 4.0 mmol/L.120 minutes; P = .508) were not improved with the energy-dense formula. CONCLUSION: In critical illness, administration of an energy-dense formula does not reduce gastric retention, increase energy delivery to the small intestine, or improve glucose absorption or glucose control; instead, there is a signal for delayed gastric emptying.

Quantifying Response to Nutrition Therapy During Critical Illness: Implications for Clinical Practice and Research? A Narrative Review.

Critical illness causes substantial muscle loss that adversely impacts recovery and health-related quality of life. Treatments are therefore needed that reduce mortality and/or improve the quality of survivorship. The purpose of this Review is to describe both patient-centered and surrogate outcomes that quantify responses to nutrition therapy in critically ill patients. The use of these outcomes in randomized clinical trials will be described and the strengths and limitations of these outcomes detailed. Outcomes used to quantify the response of nutrition therapy must have a plausible mechanistic relationship to nutrition therapy and either be an accepted measure for the quality of survivorship or highly likely to lead to improvements in survivorship. This Review identified that previous trials have utilized diverse outcomes. The variety of outcomes observed is probably due to a lack of consensus as to the most appropriate surrogate outcomes to quantify response to nutrition therapy during research or clinical practice. Recent studies have used, with some success, measures of muscle mass to evaluate and monitor nutrition interventions administered to critically ill patients.

The impact of bereavement support on psychological distress in family members: a systematic review and meta-analysis.

Background: Persistent psychological distress occurs frequently in family members of patients who die in an intensive care unit (ICU). Objective: To determine the effectiveness of bereavement interventions in reducing persisting psychological distress in bereaved family members after death in an adult ICU. Design: Systematic review and meta-analysis of studies that assessed the effect of bereavement interventions on persisting psychological distress in bereaved family members of ICU patients. Data sources: MEDLINE and APA PsycInfo databases were searched until April 2020. Review methods: Two of us independently screened titles and abstracts of identified studies, and then completed full text evaluation of selected studies. We assessed risk of bias using version 2 of the Cochrane risk-of-bias tool for randomised trials and the Newcastle-Ottawa Scale, which is designed to assess the quality of non-randomised studies in meta-analyses. We also used random effects meta-analysis to assess the effect of various interventions on total Hospital Anxiety and Depression Scale (HADS) scores. Results: From 664 citations, five studies were included - three multicentre randomised clinical trials and two single centre observational studies. Three studies tested the intervention of written bereavement support materials and two studies used narration of family members' experiences in the ICU. All studies reported HADS scores. Scores for Impact of Event Scale, Impact of Event Scale-Revised and Inventory of Complicated Grief were measured in some but not all studies. There was no effect of an intervention on HADS scores (weighted mean difference, -0.79 [95% confidence interval, -3.81 to 2.23]; I2 = 65.8%). Conclusions: Owing to limited data, and clinical and statistical heterogeneity, there is considerable uncertainty regarding whether bereavement support strategies reduce, increase or have no effect on psychological distress in bereaved family members.

A microcosting analysis of ICU expenditure in the interval between brain death and organ donation.

Objective: The cost of providing care in an intensive care unit (ICU) after brain death to facilitate organ donation is unknown. The objective of this study was to estimate expenditure for the care delivered in the ICU between the diagnosis of brain death and subsequent organ donation. Design: Cohort study of direct and indirect costs using bottom-up and top-down microcosting techniques. Setting: Single adult ICU in Australia. Participants: All patients who met criteria for brain death and proceeded to organ donation during a 13-month period between 1 January 2018 and 31 January 2019. Main outcome measures: A comprehensive cost estimate for care provided in the ICU from determination of brain death to transfer to theatre for organ donation. Results: Forty-five patients with brain death became organ donors during the study period. The mean duration of postdeath care in the ICU was 37.9 hours (standard deviation [SD], 16.5) at a mean total cost of $7520 (SD, $3136) per donor. ICU staff salaries were the greatest contributor to total costs, accounting for a median proportion of 0.72 of total expenditure (interquartile range, 0.68-0.75). Conclusions: Substantial costs are incurred in ICU for the provision of patient care in the interval between brain death and organ donation.

A fixed dose approach to thrombosis chemoprophylaxis may be inadequate in heavier critically ill patients.

Objectives: Overweight patients are at greater risk of venous thromboembolism. We aimed to describe prescribing patterns of thrombosis chemoprophylaxis in critically ill patients weighing ≥ 100 kg and quantify the effectiveness of these regimens using the surrogate biomarker of plasma anti-Xa level. Design, setting and patients: A prospective single-centre cohort study was conducted over a 6-month period. Patients weighing ≥ 100 kg who were prescribed enoxaparin for chemoprophylaxis and expected to remain in the intensive care unit for > 48 hours were eligible. Anti-Xa levels were measured once a patient had received at least three consecutive doses of enoxaparin. Peak levels were measured 4-6 hours after the third dose and trough levels were measured before the fourth dose. Anti-Xa levels were compared with established target ranges for peak and trough anti-Xa levels (0.2-0.5 IU/mL and > 0.1 IU/mL, respectively). Results: Eighty-eight patients met the eligibility criteria, and anti-Xa levels for 42 patients were obtained. Fixed dose chemoprophylaxis approaches varied considerably, with 40 mg once daily (54/88 [61%]) and 40 mg twice daily (20/88 [23%]) being the most frequently prescribed regimens. No patient had a peak anti-Xa level > 0.5 IU/mL. When comparing 40 mg once daily versus twice daily, the once daily regimen had lower median trough levels (0.01 IU/mL [interquartile range (IQR), 0.00-0.04] v 0.09 IU/mL [IQR, 0.05-0.13]; P < 0.001) and greater proportions of patients with levels below the established range (< 0.1 IU/mL) (15/16 [95%] v 7/14 [50%]; P = 0.002) and levels that were undetectable (0.00 IU/mL) (8/16 [50%] v 1/14 [7%]; P = 0.01). Conclusions: At a single centre, thrombosis chemoprophylaxis prescribing patterns for heavier critically ill patients varied considerably. Current fixed dose approaches may be inadequate in this cohort.

Assessment of muscle mass using ultrasound with minimal versus maximal pressure compared with computed tomography in critically ill adult patients.

BACKGROUND: Preserved skeletal muscle mass identified using computed tomography (CT) predicts improved outcomes from critical illness; however, CT imaging have few limitations such that it involves a radiation dose and transferring patients out of the intensive care unit. This study aimed to assess in critically ill patients the relationship between muscle mass estimates obtained using minimally invasive ultrasound techniques with both minimal and maximal pressure compared with CT images at the third lumber vertebra level. METHODS: All patients were treated in a single Australian intensive care unit. Eligible patients had paired assessments, within a 72-h window, of muscle mass by ultrasound (quadriceps muscle layer thickness in centimetres, with maximal and minimal pressure) and CT axial cross-sectional area (cm2). Data are presented as mean (standard deviation), median (interquartile range), and frequencies [n (%)]. RESULTS: Thirty-five patients [mean (standard deviation) age = 55 (16) years, median (interquartile range) body mass index = 27 (25-32) kg/m2, and 26 (74%) men] contributed 41 paired measurements. Quadriceps muscle thickness measured using the maximal pressure technique was a strong independent predictor of lumbar muscle cross-sectional area. Within a multivariate mixed linear regression model and adjusting for sex, age, and body mass index, for every 1 cm increase in quadriceps muscle layer thickness, the lumbar muscle cross-sectional area increased by 35 cm2 (95% confidence interval = 11-59 cm2). Similar univariate associations were observed using minimal pressure; however, as per multivariate analysis, there was no strength in this relationship [8 cm2 (95% confidence interval = -5 to 22 cm2)]. CONCLUSION: Ultrasound assessment of the quadriceps muscle using maximal pressure reasonably predicts the skeletal muscle at the third lumbar vertebra level of critically ill patients. However, there is substantial uncertainty within these regression estimates, and this may reduce the current utility of this technique as a minimally invasive surrogate for CT assessment of skeletal muscle mass.

Characteristics and Outcomes of Critically Ill Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease in Australia and New Zealand.

Rationale: The characteristics and outcomes of patients presenting with an acute exacerbation of chronic obstructive pulmonary disease (AECOPD) requiring intensive care unit (ICU) admission are poorly understood and there are sparse epidemiological data.Objectives: The objectives were to describe epidemiology and outcomes of patients admitted to an ICU with COPD and to evaluate whether outcomes varied over time.Methods: We studied adult ICU admissions across Australia and New Zealand between 2005 and 2017 with a diagnosis of AECOPD and used an admission diagnosis of asthma as comparator for trends over time. We measured changes in characteristics and outcomes over time using logistic regression, adjusting for illness severity using the Australian New Zealand Risk of Death model.Results: We studied 31,991 admissions with AECOPD and 11,096 with asthma. Mean (standard deviation) age for AECOPD patients was 68.3 (11.2) years, with 35.4% mechanically ventilated. For patients with AECOPD, the percentage of deaths in an ICU was 8.7% and in a hospital was 15.4% of admissions, with the proportion of 69.2% discharged home and 5.6% discharged to a high-level care facility. During the study period, the proportion of ICU admissions with AECOPD per 10,000 admissions decreased at an annual rate of 2.0 (95% confidence interval [CI], 0.8-3.2; P = 0.009) but their admission rate per million population increased annually by 4.5 (95% CI, 3.7-5.3; P < 0.0001). There was a linear reduction in mortality for AECOPD but not for asthma admissions (odds ratio annual decline: AECOPD, 0.94 [0.93-0.95] and asthma, 1.01 [0.97-1.05]; P = 0.001) and an increase in AECOPD admissions discharged to home (odds ratio annual increase, AECOPD, 1.04 [1.03-1.05] and asthma, 1.01 [0.99-1.03]; P = 0.01). The reduction in mortality was sustained after adjusting for illness severity.Conclusions: Across Australia and New Zealand, the rate of ICU admissions due to AECOPD is increasing but mortality rates are decreasing, with a corresponding increase in the home discharge rates.

Pharmacokinetic data support 6-hourly dosing of intravenous vitamin C to critically ill patients with septic shock.

OBJECTIVES: To study vitamin C pharmacokinetics in septic shock. DESIGN: Prospective pharmacokinetic study. SETTING: Two intensive care units. PARTICIPANTS: Twenty-one patients with septic shock enrolled in a randomised trial of high dose vitamin C therapy in septic shock. INTERVENTION: Patients received 1.5 g intravenous vitamin C every 6 hours. Plasma samples were obtained before and at 1, 4 and 6 hours after drug administration, and vitamin C concentrations were measured by high performance liquid chromatography. MAIN OUTCOME MEASURES: Clearance, volume of distribution, and half-life were calculated using noncompartmental analysis. Data are presented as median (interquartile range [IQR]). RESULTS: Of the 11 participants who had plasma collected before any intravenous vitamin C administration, two (18%) were deficient (concentrations < 11 µmol/L) and three (27%) had hypovitaminosis C (concentrations between 11 and 23 µmol/L), with a median concentration 28 µmol/L (IQR, 11-44 µmol/L). Volume of distribution was 23.3 L (IQR, 21.9-27.8 L), clearance 5.2 L/h (IQR, 3.3-5.4 L/h), and half-life 4.3 h (IQR, 2.6-7.5 h). For the participants who had received at least one dose of intravenous vitamin C before sampling, T0 concentration was 258 µmol/L (IQR, 162- 301 µmol/L). Pharmacokinetic parameters for subsequent doses were a median volume of distribution 39.9 L (IQR, 31.4-44.4 L), clearance 3.6 L/h (IQR, 2.6-6.5 L/h), and half-life 6.9 h (IQR, 5.7-8.5 h). CONCLUSION: Intravenous vitamin C (1.5 g every 6 hours) corrects vitamin C deficiency and hypovitaminosis C and provides an appropriate dosing schedule to achieve and maintain normal or elevated vitamin C levels in septic shock.

Any news from the prokinetic front?

PURPOSE OF REVIEW: This review provides an update of recently conducted studies and randomized controlled trials evaluating prokinetic drugs. RECENT FINDINGS: Prokinetic drugs accelerate gastric emptying and, particularly in patients with gastric dysmotility and enteral feed intolerance, their use increases the delivery of enteral nutrition. However, prokinetic drugs have not been shown to improve patient-centered outcomes in trials but benefit is assumed on the basis of observational studies, which report close associations between gastric dysmotility, enteral feed intolerance and poor outcomes, and improvement in surrogate physiological outcomes when prokinetic drugs are administered. SUMMARY: It may not be feasible to establish superiority of a prokinetic drug within a randomized controlled trial with a patient-centered event as the primary outcome. The use of metoclopramide and erythromycin as prokinetic drugs is based on observations from trials measuring surrogate physiological outcomes. Randomized controlled trials of alternative drug regimens and novel prokinetic drugs have recently been completed and results outlined.

Observed appetite and nutrient intake three months after ICU discharge.

BACKGROUND & AIMS: Oral intake is diminished immediately after ICU discharge, yet factors affecting nutritional intake after hospital discharge have not been evaluated. The aim of this study was to evaluate dietary intake and factors which may influence intake - appetite and gastric emptying - 3-months after ICU discharge. METHODS: Inception cohort study with ICU survivors compared to healthy subjects. Following an overnight fast, all participants consumed a standardized carbohydrate drink, containing 13C-octanoic acid, to measure gastric emptying. Dietary intake was assessed by recall of the preceding day and a standard weighed buffet meal 4-h post-drink. Appetite was assessed pre-drink (fasting) and pre- and post-buffet using visual analogue scales. RESULTS: Fifty-one ICU survivors (82% male; 70 ± 9 y; BMI 28 ± 6 kg/m2) and 25 healthy subjects (60% male; 67 ± 12 y; BMI 27 ± 4 kg/m2) were evaluated. From the 24-h recall ICU survivors consumed less calories (ICU 1876 (708) vs. healthy subjects 2291 (834) kcal; p = 0.025) with no difference in macronutrient intake, however reported a lower preference for fat (p < 0.001). Calorie and macronutrient intake from the weighed buffet was similar between groups: calories (ICU: 658 (301) vs. healthy subjects: 736 (325) kcal; p = 0.149); protein (ICU: 37 (19) vs. healthy subjects: 40 (17) g; p = 0.275); fat (ICU: 23 (12) vs healthy subjects: 26 (13) g; p = 0.261); and carbohydrates (ICU: 69 (35) vs. healthy subjects: 79 (42) g; p = 0.141). ICU survivors reported feeling less full regardless of time-point (p = 0.041). There was no difference in the rate of gastric emptying between the two groups (p = 0.216). CONCLUSIONS: ICU survivors reported less preference for fat and less calorie consumption than healthy subjects. However, intake of calories and macronutrients at a weighed meal was similar in the two groups, as was the rate of gastric emptying. ICU survivors reported being less full after the test meal, suggesting factors other than appetite may influence intake.

Glycated haemoglobin is increased in critically ill patients with stress hyperglycaemia: Implications for risk of diabetes in survivors of critical illness.

It remains uncertain if stress hyperglycaemia (SH) indicates a long-term predisposition to the development of type 2 diabetes. We conducted a retrospective observational study in critically ill patients and found SH to be associated with an increased HbA1c, which may indicate an increased risk of type 2 diabetes.

Intensity of early correction of hyperglycaemia and outcome of critically ill patients with diabetic ketoacidosis.

OBJECTIVES: To determine the impact of the intensity of early correction of hyperglycaemia on outcomes in patients with diabetic ketoacidosis (DKA) admitted to the intensive care unit. METHODS: We studied adult patients with DKA admitted to 171 ICUs in Australia and New Zealand from 2000 to 2013. We used their blood glucose levels (BGLs) in the first 24 hours after ICU admission to determine whether intensive early correction of hyperglycemia to ≤ 180 mg/dL was independently associated with hypoglycaemia, hypokalaemia, hypo-osmolarity or mortality, compared with partial early correction to > 180 mg/dL as recommended by DKA-specific guidelines. RESULTS: Among 8553 patients, intensive early correction of BGL was applied to 605 patients (7.1%). A greater proportion of these patients experienced hypoglycaemia (20.2% v 9.1%; P < 0.001) and/or hypo-osmolarity (29.4% v 22.0%; P < 0.001), but not hypokalaemia (16.7% v 15.6%; P = 0.47). Overall, 11 patients (1.8%) in the intensive correction group and 112 patients (1.4%) in the partial correction group died (P = 0.42). However, after adjustment for illness severity, partial early correction of BGL was independently associated with a lower risk of hypoglycaemia (odds ratio [OR], 0.38; 95% CI, 0.30-0.48; P < 0.001), lower risk of hypo-osmolarity (OR, 0.80; 95% CI, 0.65-0.98; P < 0.03) and lower risk of death (OR, 0.44; 95% CI, 0.22-0.86; P = 0.02). CONCLUSIONS: In a large cohort of patients with DKA, partial early correction of BGL according to DKA-specific guidelines, when compared with intensive early correction of BGL, was independently associated with a lower risk of hypoglycaemia, hypo-osmolarity and death.

Nutrient stimulation of mesenteric blood flow - implications for older critically ill patients.

Nutrient ingestion induces a substantial increase in mesenteric blood flow. In older persons (aged ≥ 65 years), particularly those with chronic medical conditions, the cardiovascular compensatory response may be inadequate to maintain systemic blood pressure during mesenteric blood pooling, leading to postprandial hypotension. In older ambulatory persons, postprandial hypotension is an important pathophysiological condition associated with an increased propensity for syncope, falls, coronary vascular events, stroke and death. In older critically ill patients, the administration of enteral nutrition acutely increases mesenteric blood flow, but whether this pathophysiological response is protective, or precipitates mesenteric ischaemia, is unknown. There are an increasing number of older patients surviving admission to intensive care units, who are likely to be at increased risk of postprandial hypotension, both during, and after, their stay in hospital. In this review, we describe the prevalence, impact and mechanisms of postprandial hypotension in older people and provide an overview of the impact of postprandial hypotension on feeding prescriptions in older critically ill patients. Finally, we provide evidence that postprandial hypotension is likely to be an unrecognised problem in older survivors of critical illness and discuss potential options for management.

Prior exposure to hyperglycaemia attenuates the relationship between glycaemic variability during critical illness and mortality.

OBJECTIVE: Our primary objective was to determine the impact of prior exposure to hyperglycaemia on the association between glycaemic variability during critical illness and mortality. Our secondary objectives included evaluating the relationships between prior hyperglycaemia and hyperglycaemia or hypoglycaemia during critical illness and mortality. DESIGN AND PARTICIPANTS: A single-centre, retrospective, observational study in a tertiary intensive care unit. Patients admitted to the ICU between 1 September 2011 and 30 June 2015, with diabetes recorded using ICD-10-AM coding or a glycated haemoglobin (HbA1c) level of ≥ 6.5%, were stratified by prior hyperglycaemic level (HbA1c < 6.5%, 6.5%-8.5%, or > 8.5%). MAIN OUTCOME MEASURES: Glycaemic variability was assessed as the blood glucose coefficient of variation during the patient's stay in the ICU. Multivariate logistic regression and marginal predictive plots were used to assess the impact of prior hyperglycaemia on the association between glycaemic metrics and mortality. RESULTS: We studied 1569 patients with diabetes (HbA1c < 6.5%, n = 495; HbA1c 6.5%-8.5%, n = 731; and HbA1c > 8.5%, n = 343). Glycaemic variability was strongly associated with hospital mortality (P = 0.001), but this asso ciation showed a significant interaction with prior hyperglycaemia (P = 0.011), such that for patients with HbA1c > 8.5%, increasing glycaemic variability was not associated with increased mortality. Acute hyperglycaemia was strongly associated with mortality (P < 0.0001) and also showed a significant interaction with prior hyperglycaemia (P = 0.001), such that for patients with HbA1c > 8.5%, acute hyperglycaemia was not associated with mortality. Hypoglycaemia was also associated with mortality (P < 0.0001), but prior exposure to hyperglycaemia had a lesser effect on this relationship. CONCLUSION: Prior exposure to hyperglycaemia attenuates the association between glycaemic variability and mortality in critically ill patients with diabetes.

A prospective observational study of the effect of critical illness on ultrastructural and microscopic morphology of duodenal mucosa.

OBJECTIVE: Disturbed intestinal barrier function due to 'leaky' tight junctions may cause secondary sepsis via paracellular translocation across the gut wall. Our objective was to describe the effects of critical illness on duodenal morphology and ultrastructure. DESIGN, SETTING AND PARTICIPANTS: Prospective observational study of 12 mechanically ventilated critically ill patients in an intensive care unit and 15 control participants in an outpatient endoscopy suite. INTERVENTION: We took six endoscopic biopsy samples of the duodenum from each participant for analysis by electron and light microscopy. MAIN OUTCOME MEASURES: Our primary outcome was tight junction morphology, examined with electron microscopy. Secondary outcomes were microvillus length and density, vascular endothelium morphology and mitochondrial density and morphology, examined with electron microscopy, and morphology examined with light microscopy. RESULTS: We observed no abnormalities of tight junction ultrastructure in either group. There was a tendency towards shorter microvilli in the critically ill group: mean length in critically ill patients, 1.17 µm (interquartile range [IQR], 1.05-1.60 µm) v mean length in control patients, 1.58 µm (IQR, 1.30-1.72 µm); P = 0.07. There was a tendency towards less dense microvilli in the critically ill group: mean density in critically ill patients, 7.29 microvilli/µm (IQR, 6.83-8.05 microvilli/µm) v mean density in control patients, 8.23 microvilli/µm (IQR, 7.34-9.11 microvilli/µm); P = 0.07. Vascular endothelium appeared normal in all critically ill patients and abnormal in one control participant. Abnormal mitochondrial morphology was noted in one critically ill patient and one control participant, and no differences were seen in mitochondrial density. Using light microscopy, we saw more apoptotic cells in the critically ill patients (P = 0.018), but villus height, crypt depth and lymphocyte density were normal. CONCLUSIONS: We did not detect any morphological abnormalities of duodenal tight junctions in critically ill patients. Our results should be interpreted with caution because of the small sample population, but our observations challenge the concept that paracellular translocation facilitates secondary sepsis.