Fasting does not guarantee empty stomach in the intensive care unit: A prospective ultrasonographic evaluation (The NUTRIGUS study)

ASRA pain medicine narrative review and expert practice recommendations for gastric point-of-care ultrasound to assess aspiration risk in medically complex patients undergoing regional anesthesia and pain procedures

Gastric point-of-care ultrasound (POCUS) may offer clinical value in assessing aspiration risk among medically complex patients undergoing regional anesthesia and pain procedures. While the American Society of Anesthesiologists (ASA) preoperative fasting guidelines primarily apply to healthy individuals, medically complex populations often present with differing gastric emptying and aspiration risk. This narrative review, conducted by the American Society of Regional Anesthesia and Pain Medicine (ASRA-PM), adhered to PRISMA guidelines and was registered with PROSPERO. It focused on seven medically complex patient groups: those who are pregnant, obese, diabetic, have gastroesophageal reflux disease (GERD), are receiving emergency care, are enterally fed, or are taking GLP-1 receptor agonists (GLP-1RA). Study quality was assessed using the Mixed Methods Appraisal Tool (MMAT). Practice recommendations were developed using an iterative expert consensus process, with final recommendations based on evidence strength, clinical relevance, and expert agreement. Findings support the use of gastric POCUS in patients in active labor, those undergoing urgent cesarean sections, and those with diabetes. Conditional support is given for obesity, emergency care, enteral feeding, and GLP-1RA use. Routine use is not recommended in non-laboring pregnancies, elective cesarean delivery, or GERD. While gastric POCUS may aid with aspiration risk evaluation, its use should complement clinical judgment. Implementation may be limited by practical and training constraints, requiring individualized decision-making. These recommendations serve as a foundation for future research and potential clinical guideline development. PROSPERO registration number: CRD42023445927.

Feeding interruptions for extubation and other procedures

PURPOSE OF REVIEW

The objective of this review is to examine the available evidence concerning feeding interruptions before extubation and other medical procedures in ICUs. We will analyze the physiological mechanisms involved, the potential risks associated with feeding interruptions, as well as the results of recent clinical studies. Additionally, we will explore current practices and recommendations from major professional societies, as well as recent innovations aimed at minimizing feeding interruptions.

RECENT FINDINGS

Fasting before extubation is a common yet heterogeneous practice, varying across ICUs. Although dysphagia is a frequent complication after extubation, its prevalence decreases over time. However, physiologically, fasting before extubation appears ineffective in reducing gastric content or preventing aspiration. The Ambroisie study demonstrated that continuing enteral nutrition up to extubation is not inferior to a 6 h fasting strategy in terms of extubation failure at 7 days. The management of perioperative nutrition in intubated patients is debated. A retrospective study found no significant difference in postoperative respiratory events between patients fasting for at least 6 h and those fasting less or not at all but further prospective randomized studies are needed for definitive conclusions. For abdominal and digestive surgeries, fasting remains necessary to simplify procedures and reduce contamination risks. For invasive ICU procedures, such as catheter placement, the continuation of enteral nutrition appears reasonable. However, for percutaneous tracheotomy, limited evidence suggests no clear benefit from fasting, though the risk of large-volume aspiration during the procedure raises concerns. The approach to nutrition in this context requires further investigation.

SUMMARY

Fasting before extubation in ICUs is a common practice inherited from anesthesia, aiming to reduce the risk of aspiration. The Ambroisie study demonstrates that continuing enteral nutrition until extubation is not inferior to a 6 h fasting strategy regarding extubation failure at 7 days.

Preprocedural fasting policies for patients receiving tube feeding: A national survey

BACKGROUND

Patients who are critically ill frequently accrue substantial nutrition deficits due to multiple episodes of prolonged fasting prior to procedures. Existing literature suggests that, for most patients receiving tube feeding, the aspiration risk is low. Yet, national and international guidelines do not address fasting times for tube feeding, promoting uncertainty regarding optimal preprocedural fasting practice. We aimed to characterize current institutional fasting practices in the United States for patients with and without a secure airway, with variable types of enteral access, for representative surgical procedures.

METHODS

The survey was distributed to a purposive sample of academic institutions in the United States. Reponses were reported as restrictive (6-8 h preprocedurally) or permissive (<6 h or continued intraprocedurally) feeding policies. Differences between level 1 trauma centers and others, and between burn centers and others, were evaluated.

RESULTS

The response rate was 40.3% (56 of 139 institutions). Responses revealed a wide variability with respect to current practices, with more permissive policies reported in patients with secure airways. In patients with a secure airway, Level 1 trauma centers were significantly more likely to have permissive fasting policies for patients undergoing an extremity incision and drainage for each type of feeding tube surveyed.

CONCLUSIONS

Current hospital policies for preprocedural fasting in patients receiving tube feeds are conflicting and are frequently more permissive than guidelines for healthy patients receiving oral nutrition. Prospective research is needed to establish the safety and clinical effects of various fasting practices in tube-fed patients.

Continued enteral nutrition until extubation compared with fasting before extubation in patients in the intensive care unit: an open-label, cluster-randomised, parallel-group, non-inferiority trial

BACKGROUND

Fasting is frequently imposed before extubation in patients in intensive care units, with the aim to reduce risk of aspiration. This unevaluated practice might delay extubation, increase workload, and reduce caloric intake. We aimed to compare continued enteral nutrition until extubation with fasting before extubation in patients in the intensive care unit.

METHODS

We conducted an open-label, cluster-randomised, parallel-group, non-inferiority trial in 22 intensive care units in France. Patients aged 18 years or older were eligible for enrolment if they had received invasive mechanical ventilation for at least 48 h in the intensive care unit and received prepyloric enteral nutrition for at least 24 h at the time of extubation decision. Centres were randomly assigned (1:1) to continued enteral nutrition until extubation or 6-h fasting with concomitant gastric suctioning before extubation, to be applied for all patients within the unit. Masking was not possible because of the nature of the trial. The primary outcome was extubation failure (composite criteria of reintubation or death) within 7 days after extubation, assessed in both the intention-to-treat and per-protocol populations. The non-inferiority margin was set at 10%. Pneumonia within 14 days of extubation was a key secondary endpoint. This trial is now complete and is registered with ClinicalTrials.gov, NCT03335345.

FINDINGS

Between April 1, 2018, and Oct 31, 2019, 7056 patients receiving enteral nutrition and mechanical ventilation were admitted to the intensive care units and 4198 were assessed for eligibility. 1130 patients were enrolled and included in the intention-to-treat population and 1008 were included in the per-protocol population. In the intention-to-treat population, extubation failure occurred in 106 (17·2%) of 617 patients assigned to receive continued enteral nutrition until extubation versus 90 (17·5%) of 513 assigned to fasting, meeting the a priori defined non-inferiority criterion (absolute difference -0·4%, 95% CI -5·2 to 4·5). In the per-protocol population, extubation failure occurred in 101 (17·0%) of 595 patients assigned to receive continued enteral nutrition versus 74 (17·9%) of 413 assigned to fasting (absolute difference -0·9%, 95% CI -5·6 to 3·7). Pneumonia within 14 days of extubation occurred in ten (1·6%) patients assigned to receive continued enteral nutrition and 13 (2·5%) assigned to fasting (rate ratio 0·77, 95% CI 0·22 to 2·69).

INTERPRETATION

Continued enteral nutrition until extubation in critically ill patients in the intensive care unit was non-inferior to a 6-h fasting maximum gastric vacuity strategy comprising continuous gastric tube suctioning, in terms of extubation failure within 7 days (a patient-centred outcome), and thus represents a potential alternative in this population.

FUNDING

French Ministry of Health.

TRANSLATION

For the Chinese translation of the abstract see Supplementary Materials section.

Fasting practices of enteral nutrition delivery for airway procedures in critically ill adult patients: A scoping review

BACKGROUND

There is limited understanding of fasting practices and reported safety concerns for airway procedures in critically ill adults.

OBJECTIVE

To describe fasting practices including safety concerns for airway procedures in critically ill adult patients in the reported literature.

INCLUSION CRITERIA

Studies conducted in adult critically ill patients receiving enteral nutrition (EN) and undergoing an airway procedure (endotracheal intubation, endotracheal extubation, and tracheostomy) were included if EN fasting practices and/or prespecified nutrition and clinical outcomes were reported.

METHODS

A scoping review using the Joanna Briggs Institute methodology was conducted. MEDLINE, Embase, and CINAHL were searched from 2000 to January 19, 2022. Results are presented via narrative synthesis.

RESULTS

Fourteen studies were included, with only one randomised control trial (RCT). Twelve studies reported on fasting practices with varied EN fasting durations (0-34 h) and two reported data on nutrition adequacy. Three studies investigated continued EN in one study arm and four studies minimised fasting duration by including gastric suctioning prior to the airway procedure. Safety concerns primarily related to aspiration events (61%) were reported in nine studies.

CONCLUSION

In the reported literature, there is wide variation in EN fasting practices for airway procedures in critically ill patients with limited evidence to inform practice.

Impact of fasting on the gastric volume of critically ill patients before extubation: a prospective observational study using gastric ultrasound

Background

A period of fasting before tracheal extubation of ventilated patients in the ICU is common practice, aiming to reduce gastric volume and aspiration risk. As the volume of gastric content is unknown at the time of extubation, the efficacy of this practice is uncertain.

Methods

A prospective, observational study using gastric ultrasound was undertaken. Images were obtained at four time points: (i) at baseline, with gastric feeds running; (ii) after suctioning of gastric contents through a gastric tube; (iii) after a 4 h period with no gastric feed running; and (iv) after both a 4 h fasting period and gastric tube suctioning. The primary outcome was the proportion of patients classed as low risk of aspiration with each intervention, using qualitative and quantitative gastric ultrasound.

Results

Fifty-four patients in the ICU were enrolled. Forty-four (81%) subjects had images that were suitable for analysis. Suctioning of stomach content through a gastric tube and fasting were equivalent with 39/44 (88.6%) and 5/44 (11.4%) subjects classified as low risk and at risk of aspiration, respectively. A period of fasting followed by suction resulted in 41/44 (93.2%) patients being at low risk.

Conclusions

Suctioning of stomach contents through the gastric tube and a 4 h fasting period appear equivalent at reducing gastric volume below a safe threshold. A small percentage did not reach the threshold despite all interventions.

Planned Peri-Extubation Fasting in Critically Ill Children: An International Survey of Practice

INTRODUCTION

Cumulative energy/protein deficit is associated with impaired outcomes in pediatric intensive care Units (PICU). Enteral nutrition is the preferred mode, but its delivery may be compromised by periods of feeding interruptions around procedures, with peri-extubation fasting the most common procedure. Currently, there is no evidence to guide the duration of the peri-extubation fasting in PICU. Therefore, we aimed to explore current PICU fasting practices around the time of extubation and the rationales supporting them.

MATERIALS AND METHODS

A cross sectional electronic survey was disseminated via the European Pediatric Intensive Care Society (ESPNIC) membership. Experienced senior nurses, dieticians or doctors were invited to complete the survey on behalf of their unit, and to describe their practice on PICU fasting prior to and after extubation.

RESULTS

We received responses from 122 PICUs internationally, mostly from Europe. The survey confirmed that fasting practices are often extrapolated from guidelines for fasting prior to elective anesthesia. However, there were striking differences in the duration of fasting times, with some units not fasting at all (in patients considered to be low risk), while others withheld feeding for all patients. Fasting following extubation also showed large variations in practice: 46 (38%) and 26 (21%) of PICUs withheld oral and gastric/jejunal nutrition more than 5 h, respectively, and 45 (37%) started oral feeding based on child demand. The risk of vomiting/aspiration and reducing nutritional deficit were the main reasons for fasting children [78 (64%)] or reducing fasting times [57 (47%)] respectively.

DISCUSSION

This variability in practices suggests that shorter fasting times might be safe. Shortening the duration of unnecessary fasting, as well as accelerating the extubation process could potentially be achieved by using other methods of assessing gastric emptiness, such as gastric point of care ultrasonography (POCUS). Yet only half of the units were aware of this technique, and very few used it.