Inter-relationships between gastric emptying and glycaemia: Implications for clinical practice

Gastric emptying (GE) exhibits a wide inter-individual variation and is a major determinant of postprandial glycaemia in health and diabetes; the rise in blood glucose following oral carbohydrate is greater when GE is relatively more rapid and more sustained when glucose tolerance is impaired. Conversely, GE is influenced by the acute glycaemic environment acute hyperglycaemia slows, while acute hypoglycaemia accelerates it. Delayed GE (gastroparesis) occurs frequently in diabetes and critical illness. In diabetes, this poses challenges for management, particularly in hospitalised individuals and/or those using insulin. In critical illness it compromises the delivery of nutrition and increases the risk of regurgitation and aspiration with consequent lung dysfunction and ventilator dependence. Substantial advances in knowledge relating to GE, which is now recognised as a major determinant of the magnitude of the rise in blood glucose after a meal in both health and diabetes and, the impact of acute glycaemic environment on the rate of GE have been made and the use of gut-based therapies such as glucagon-like peptide-1 receptor agonists, which may profoundly impact GE, in the management of type 2 diabetes, has become commonplace. This necessitates an increased understanding of the complex inter-relationships of GE with glycaemia, its implications in hospitalised patients and the relevance of dysglycaemia and its management, particularly in critical illness. Current approaches to management of gastroparesis to achieve more personalised diabetes care, relevant to clinical practice, is detailed. Further studies focusing on the interactions of medications affecting GE and the glycaemic environment in hospitalised patients, are required.

Protein delivery in mechanically ventilated adults in Australia and New Zealand: current practice

Objective: To quantify current protein prescription and delivery in critically ill adults in Australia and New Zealand and compare it with international guidelines. Design: Prospective, multicentre, observational study. Setting: Five intensive care units (ICUs) across Australia and New Zealand. Participants: Mechanically ventilated adults who were anticipated to receive enteral nutrition for ≥ 24 hours. Main outcome measures: Baseline demographic and nutrition data in ICU, including assessment of requirements, prescription and delivery of enteral nutrition, parenteral nutrition and protein supplementation, were collected. The primary outcome was enteral nutrition protein delivery (g/kg ideal body weight [IBW] per day). Data are reported as mean ± standard deviation or n (%). Results: 120 patients were studied (sex, 60% male; mean age, 59 ± 16 years; mean admission APACHE II score, 20 ± 8). Enteral nutrition was delivered on 88%, parenteral nutrition on 6.8%, and protein supplements on 0.3% of 1156 study days. For the 73% (88/120) of patients who had a nutritional assessment, the mean estimated protein requirements were 99 ± 22 g/day (1.46 ± 0.55 g/kg IBW per day). The mean daily protein delivery was 54 ± 23 g (0.85 ± 0.35 g/kg IBW per day) from enteral nutrition and 56 ± 23 g (0.88 ± 0.35 g/kg IBW per day) from all sources (enteral nutrition, parenteral nutrition, protein supplements). Protein delivery was ≥ 1.2 g/kg IBW per day on 29% of the total study days per patient. Conclusions: Protein delivery as a part of current usual care to critically ill adults in Australia and New Zealand remains below that recommended in international guidelines.

Acceleration of Gastric Emptying by Insulin-Induced Hypoglycemia is Dependent on the Degree of Hypoglycemia

CONTEXT

Hypoglycemia is a major barrier to optimal glycemic control in insulin-treated diabetes. Recent guidelines from the American Diabetes Association have subcategorized "non-severe" hypoglycemia into level 1 (<3.9 mmol/L) and 2 (<3 mmol/L) hypoglycemia. Gastric emptying of carbohydrate is a major determinant of postprandial glycemia but its role in hypoglycemia counter-regulation remains underappreciated. "Marked" hypoglycemia (~2.6 mmol/L) accelerates gastric emptying and increases carbohydrate absorption in health and type 1 diabetes, but the impact of "mild" hypoglycemia (3.0-3.9 mmol/L) is unknown.

OBJECTIVE

To determine the effects of 2 levels of hypoglycemia, 2.6 mmol/L ("marked") and 3.6 mmol/L ("mild"), on gastric emptying in health.

DESIGN, SETTING, AND SUBJECTS

Fourteen healthy male participants (mean age: 32.9 ± 8.3 years; body mass index: 24.5 ± 3.4 kg/m2) from the general community underwent measurement of gastric emptying of a radiolabeled solid meal (100 g beef) by scintigraphy over 120 minutes on 3 separate occasions, while blood glucose was maintained at either ~2.6 mmol/L, ~3.6 mmol/L, or ~6 mmol/L in random order from 15 minutes before until 60 minutes after meal ingestion using glucose-insulin clamp. Blood glucose was then maintained at 6 mmol/L from 60 to 120 minutes on all days.

RESULTS

Gastric emptying was accelerated during both mild (P = 0.011) and marked (P = 0.001) hypoglycemia when compared to euglycemia, and was more rapid during marked compared with mild hypoglycemia (P = 0.008). Hypoglycemia-induced gastric emptying acceleration during mild (r = 0.57, P = 0.030) and marked (r = 0.76, P = 0.0014) hypoglycemia was related to gastric emptying during euglycemia.

CONCLUSION

In health, acceleration of gastric emptying by insulin-induced hypoglycemia is dependent on the degree of hypoglycemia and baseline rate of emptying.

Postoperative nutrition practices in abdominal surgery patients in a tertiary referral hospital Intensive Care Unit: A prospective analysis

Background:

Benefit of early enteral feeds in surgical patients admitted to Intensive Care Units (ICUs) has been emphasized by several studies. Apprehensions about anastomotic leaks in gastrointestinal surgical patients prevent initiation of early enteral nutrition (EN). The impact of these practices on outcome in Indian scenario is less studied.

Aims:

This study compares the impact of early EN (within 48 h after surgery) with late EN (48 h postsurgery) on outcomes in abdominal surgical ICU patients.

Settings and Design:

Postabdominal surgery patients admitted to a tertiary referral hospital ICU over a 2-year period were analyzed.

Methods:

Only patients directly admitted to ICU after abdominal surgery were included in this study. ICU stay>3 days was considered as prolonged; with average ICU length of stay (LOS) for this ICU being 3 days. The primary outcome was in-patient mortality. ICU LOS, hospital LOS, infection rates, and ventilator days were secondary outcome measures. Acute Physiology and Chronic Health Evaluation II scores were calculated. SPSS and Microsoft Excel were used for analysis.

Results:

Of 91 ICU patients included, 58 received early EN and 33 late EN. Hospital LOS and infection rates were less in early EN group. Use of parenteral nutrition (odds ratio [OR] 5.25, 95% confidence interval (CI); P = 0.003) and number of nil-per-oral days (OR 8.25, 95% CI; P ≤ 0.001) were other predictors of prolonged LOS.

Conclusions:

Early EN in postabdominal surgery ICU patients was associated with reduced hospital LOS and infection rates. ICU LOS, duration of mechanical ventilation and mortality rates did not vary.