Efficacy and Tolerability of Non‐Routine Gastric Residual Volume Monitoring in Mechanically Ventilated Adults Receiving Early Enteral Nutrition: A Randomised Controlled Non‐Inferiority Trial

ABSTRACT

Background

Patients receiving early enteral nutrition in the intensive care unit (ICU) often undergo gastric residual volume (GRV) monitoring to assess feeding tolerance. Despite guidelines recommending non‐routine monitoring, many ICUs continue to perform 4‐hourly GRV checks, which may lead to unnecessary feeding interruptions and increased nursing workload.

Aim

To explore the impact of non‐routine monitoring of GRV on feeding intolerance in patients receiving early enteral nutrition.

Study Design

This was a randomised controlled non‐inferiority trial conducted in a tertiary A‐level hospital. Patients receiving mechanical ventilation and continuous enteral nutrition were randomly assigned to an intervention group (GRV monitored once at 12 h, then once daily) or a control group (routine 4‐hourly monitoring). Feeding intolerance was defined as vomiting or GRV > 200 mL.

Results

Each group included 52 patients. Feeding intolerance occurred in 36.5% of the intervention group versus 21.2% of controls, with an absolute difference of 15.4% (95% CI –2.0 to +31.6; p = 0.13), indicating a non‐significant difference between the two groups. Competing‐risk models showed no significant between‐group difference (adjusted HR 1.35, 95% CI 0.62 to 2.92; p = 0.45). Higher BMI was associated with lower intolerance risk (HR 0.91 per 1‐point increase; p = 0.044), while higher SOFA score increased risk (HR 1.14 per 1‐point increase; p = 0.014).

Conclusions

Reducing GRV monitoring to once daily did not increase the incidence of feeding intolerance.

Relevance to Clinical Practice

The findings of this study support critical care nurses in reducing gastric residual volume monitoring to once daily, as this does not increase the incidence of feeding intolerance. However, attention should be paid to patients at higher risk of feeding intolerance.

Trial Registration: This study was registered in the Chinese Clinical Trial Registry (Registration number: ChiCTR2000038245).

Impact Statements

• What is known about this topic

  • ○
    International clinical guidelines have moved away from recommending routine GRV monitoring for critically ill patients receiving enteral nutrition, citing a lack of evidence for its benefit in preventing complications like aspiration.
  • ○
    Despite these recommendations, frequent (e.g., 4‐hourly) GRV monitoring remains a common nursing practice worldwide, often driven by institutional protocol and perceived patient safety, leading to potential interruptions in feeding and increased nursing workload.
  • ○
    The evidence supporting the safety and efficacy of reduced GRV monitoring frequency, particularly within specific healthcare contexts, is limited, creating a gap between international guidelines and local clinical implementation.
• What this paper adds

  • ○
    This randomised controlled non‐inferiority trial provides direct evidence from an ICU setting that reducing GRV monitoring to once daily (with an initial check at the 12‐h peak) is not inferior to conventional 4‐hourly monitoring regarding the risk of feeding intolerance (defined as vomiting or GRV > 200 mL).
  • ○
    It identifies patient‐specific risk factors, demonstrating that a higher SOFA score is an independent risk factor for feeding intolerance, while a higher BMI may be protective. This aids in stratifying patient risk and personalising monitoring approaches.
  • ○
    The study offers a pragmatic and safe monitoring protocol (once at 12 h, then daily) for institutions transitioning away from rigid, frequent checks, thereby supporting guideline implementation, reducing unnecessary feeding interruptions and optimising nursing resource allocation.

1. Introduction

Patients admitted to the intensive care unit (ICU) are often in a state of heightened catabolism and increased nutritional demand [1]. For those unable to maintain oral intake, timely and adequate nutritional support is a cornerstone of therapy, linked to improved clinical outcomes such as reduced infection rates, shorter duration of mechanical ventilation and decreased mortality [2, 3]. Enteral nutrition (EN), when feasible, is the preferred route over parenteral nutrition due to its role in preserving gut mucosal integrity, modulating immune function and maintaining the gut microbiome [4]. Consequently, the early initiation of EN and the consistent achievement of daily caloric and protein targets are critical priorities in the management of critically ill patients [5].

Critically ill patients often present with multiple comorbidities, some of which may lead to poor tolerance of enteral nutrition (EN). For instance, in patients with diabetes, diabetic gastroparesis is a common complication primarily involving autonomic neuropathy, the direct inhibitory effect of hyperglycaemia on gastrointestinal motility, as well as factors such as inflammation and oxidative stress [6, 7]. Diabetic gastroparesis is characterised by delayed gastric emptying in the absence of mechanical obstruction, indicating that these patients are more susceptible to enteral nutrition intolerance [8]. Therefore, assessing EN tolerance is essential to balance the benefits of feeding against the risks of gastrointestinal complications [9]. Gastric residual volume (GRV) measurement, a bedside procedure involving the aspiration of gastric contents via a feeding tube, has been traditionally employed as a simple surrogate marker of gastric emptying and feeding intolerance [10, 11]. For decades, frequent GRV monitoring (e.g., every 4–6 h) has been embedded in routine ICU nursing practice worldwide, driven by the intent of early detection of intolerance and prevention of aspiration [12, 13].

2. Background

However, the clinical utility and optimal frequency of GRV monitoring are subjects of intense and ongoing debate [14, 15] A robust body of evidence, particularly strengthened in the last 5 years, challenges the value of this routine practice [16]. A study suggests that 4‐hourly checks do not prevent aspiration and that frequent monitoring can lead to interruptions in feeding, resulting in inadequate caloric intake and failure to meet feeding goals [17]. From a nursing perspective, the procedure adds to workload, takes time away from other direct patient care activities and may not enhance patient safety.

In response to this evolving evidence, recent international clinical guidelines from major societies have strongly shifted their recommendations, advising against the routine use of GRV monitoring [18]. Despite these clear and evidence‐based recommendations, a significant and persistent gap exists between guideline publication and bedside implementation. Recent surveys from the UK, Europe and other regions continue to show that a majority of ICUs and nurses still perform regular GRV checks, with 4‐hourly monitoring remaining deeply entrenched in institutional protocols and nursing culture [13, 19]. This discrepancy is particularly pronounced in certain healthcare settings or regions. Change has been hindered by a lack of specific evidence, slow updates to nursing standards and a historical reliance on tradition, all perpetuating the use of frequent GRV checks.

For medical institutions that still perform GRV monitoring, determining a minimal yet effective and evidence‐informed monitoring strategy becomes a pragmatic clinical question. Studies suggest that GRV in critically ill patients on continuous EN follows a pattern, often gradually increasing to a peak around 12 h after initiation [20]. This insight provides a rationale for a targeted monitoring approach. A once‐daily monitoring protocol timed to this physiological peak could maintain a safety check while reducing the burdens of frequent, low‐yield measurements.

3. Aims and Objectives

This study aimed to compare the effect of a once‐daily gastric residual volume (GRV) monitoring protocol versus conventional 4‐hourly monitoring on the incidence of feeding intolerance in mechanically ventilated adults receiving early enteral nutrition. We hypothesised that implementing a pragmatic, once‐daily GRV monitoring protocol (with an initial check at the 12‐h peak) would be non‐inferior to the conventional 4‐hourly monitoring protocol with respect to feeding intolerance. By generating robust, locally relevant evidence, this research can facilitate the translation of international guidelines into local practice, offering a safe and efficient strategy to optimise EN delivery, reduce unnecessary nursing workload and improve the care of critically ill patients.

4. Design and Methods

4.1. Setting and Sample

This was a randomised controlled non‐inferiority trial conducted in the medical, respiratory and emergency intensive care units (ICUs) of a tertiary Grade A hospital, between October 2020 and January 2023, and was reported in accordance with the CONSORT (Consolidated Standards of Reporting Trials) statement. To ensure a representative sample, consecutive enrollment was used for patient recruitment. All patients admitted to the participating ICUs during the study period who met the eligibility criteria were invited to participate, minimising selection bias. Patients were randomly assigned to the intervention or control group using a random number table (numbers ≤ 0.5 for the intervention group and > 0.5 for the control group). Due to the nature of the intervention, blinding was not feasible. Consecutive enrollment was used for patient recruitment. Patients admitted to the participating ICUs during the study period were included if they met the following criteria: (1) age > 18 years, (2) ICU admission with mechanical ventilation within 48 h and receiving nasogastric enteral nutrition and (3) expected ICU stay ≥ 3 days. Patients using a nasojejunal tube for enteral nutrition were excluded.

The intervention protocol was developed based on clinical guidelines for enteral nutrition and feeding tolerance assessment, as well as previous studies indicating GRV peaks approximately 12 h after feeding initiation. Input was also obtained from critical care nursing experts and ICU directors to determine appropriate monitoring frequency and methods. In the intervention group, GRV was monitored once at 12 h after initiation of continuous enteral nutrition and then daily at the same time. Monitoring involved aspirating fluid with a 20‐mL syringe until no further fluid could be withdrawn, recording the total volume and discarding the aspirate. If GRV exceeded 200 mL or the patient vomited, the physician was notified, and GRV monitoring resumed every 4 h per medical advice. In the control group, routine GRV monitoring was conducted every 4 h (01:00, 05:00, 09:00, 13:00, 17:00, 21:00) using the same method.

Based on ICU retrospective data, the incidence of feeding‐related complications (GRV > 200 mL or vomiting) with 4‐hourly monitoring was 13%. A non‐inferiority margin of 10% was pre‐specified, consistent with prior guidelines and literature. It was hypothesised that daily monitoring would result in an 8% incidence of complications. With 80% power and α = 0.05, the required sample size was calculated as 104 patients.

4.2. Data Collection

The primary investigator designed a standardised electronic data collection form after reviewing the literature. Three head nurses from the medical, respiratory and emergency ICUs collected data by reviewing the hospital information system and completing the forms before patient discharge. Collected variables included demographics, body mass index (BMI), Sequential Organ Failure Assessment (SOFA) score, diabetes mellitus, admission diagnosis, continuous renal replacement therapy (CRRT), prone positioning and sedative agents. From ICU day 3 to day 7, the following clinical outcomes were assessed daily: maximum GRV, feeding complications, ICU length of stay, ICU death and ventilator days. The principal investigator randomly sampled 5% of medical records from each ward to verify consistency between forms and nursing records, ensuring data accuracy and reliability.

Feeding intolerance lacks a universally accepted definition. Based on prior evidence, it typically manifests as abdominal distension, diarrhoea, vomiting or elevated GRV. Because abdominal distension and diarrhoea may be influenced by other factors (e.g., disease or antibiotics), this study recorded only vomiting and maximum GRV. Vomiting was defined as the expulsion of gastric contents or visible enteral nutrition fluid from the mouth. Maximum GRV referred to the highest value observed during daily monitoring. Feeding intolerance was operationally defined as either vomiting or GRV > 200 mL, a cut‐off commonly reported in studies and clinical practice [21, 22, 23]. The primary outcome was the 7‐day feeding intolerance rate, defined as the proportion of ICU patients who met the diagnostic criteria within the 7‐day period.

4.3. Data Analysis

Continuous variables were summarised as mean (standard deviation) or median (interquartile range) and categorical variables as percentages. Group comparisons used ANOVA for normally distributed continuous data and χ ² tests for categorical variables. Non‐parametric comparisons employed the Hodges–Lehmann estimator from the Mann–Whitney U test to calculate pseudo‐median differences. Normality was assessed using the Shapiro–Wilk test.

We estimated the between‐group risk difference for enteral nutrition intolerance and its two‐sided 95% confidence interval (CI). Non‐inferiority was assessed by comparing the upper limit of this two‐sided 95% CI with the pre‐specified non‐inferiority margin of 10%. Because death could preclude the occurrence of intolerance, we conducted a competing‐risk analysis using a Fine–Grey subdistribution hazards model. The multivariable model was adjusted for pre‐specified covariates including age, sex, BMI, diabetes mellitus, SOFA score, prone position and sedative agents to account for potential confounding variables. Analyses were conducted in R (v4.3.0; R Software for Statistical Computing, Vienna, Austria) with visualisation in GraphPad Prism (v9.0; GraphPad Software, San Diego, CA).

4.4. Ethical Approvals

This study was approved by the Institutional Review Board of Peking Union Medical College Hospital (Approval No. JS‐2148; Approval Date: October 22, 2019) on October 22nd, 2019. In accordance with the Declaration of Helsinki, written informed consent was obtained from all participants or their legal surrogates prior to study enrollment. Specifically, for patients who were alert and capable of decision‐making, consent was obtained directly from the patients themselves. For patients who were unconscious, sedated or otherwise unable to provide consent due to their critical condition, consent was obtained from their next of kin or legally authorised representatives.

4.5. Trial Registration

This study was registered in our country's Clinical Trial Registry (Registration number: ChiCTR2000038245).

5. Results

Figure 1 illustrates the participant recruitment process. A total of 104 individuals were included, with 52 randomised to the intervention group and 52 to the control group. Participant demographics and baseline clinical characteristics are presented in Table 1, with no significant differences observed between the groups. Outcomes for the intervention and control groups were calculated and compared based on study indicators (Table 2). Maximum GRV was comparable between groups (95 mL vs. 50 mL; difference, 10 mL; 95% confidence interval [CI], −10 to +45; p = 0.398). Moreover, the proportions of patients experiencing vomiting (difference, 1.9%; 95% CI, −8.0 to +12.2%; p = 1.000) and large GRV (difference, 15.4%; 95% CI, 1.3 to 31.1%; p = 0.113) were similar. Overall, 19 of 52 patients (36.5%) in the intervention group and 11 of 52 patients (21.2%) in the control group exhibited intolerance to enteral nutrition (difference, 15.4%; 95% CI, −2.0 to +31.6%; p = 0.130).

FIGURE 1.

Process of patient recruitment.

TABLE 1.

Baseline characteristics of the two groups.

	GRV monitored daily	GRV monitored every 4 h	p value
N	52	52
Sex (male, %)	34 (65)	37 (71)	0.673
Age	64.0 ± 15.4	64.2 ± 16.9	0.947
BMI	23.2 ± 4.2	23.7 ± 4.4	0.607
SOFA score at admission	8.6 ± 3.8	6.9 ± 3.5	0.021
Diabetes mellitus, n (%)	22 (42)	12 (23)	0.060
Cause of ICU admission, n (%)			0.589
Acute respiratory failure	43 (82.7)	40 (76.9)
Major postoperative surgery	0 (0)	0 (0)
Shock	3 (5.8)	5 (9.6)
Central nervous disease	2 (3.8)	4 (7.7)
Cardia arrest	2 (3.8)	2 (3.8)
Other	3 (5.8)	2 (3.8)
CRRT, n (%)	5 (9.6)	5 (9.6)	0.566
Proneposition, n (%)	14 (26.9)	15 (28.8)	0.827
Sedativeagents, n (%)	43 (82.7)	42 (80.8)	0.800

Note: Data are presented as mean ± SD for continuous variables and n (%) for categorical variables.

Abbreviations: BMI, body mass index; CRRT, continuous renal replacement therapy; GRV, gastric residual volume; ICU, intensive care unit; SOFA, Sequential Organ Failure Assessment.

TABLE 2.

Feeding efficacy and clinical outcomes of the two groups.

	GRV monitored daily	GRV monitored every 4 h	Percentage or median difference (95% CI)	p value
Maximum gastric residual volume, mL	95 (18–203)	50 (10–176)	10 (−10 to +45)	0.398
Vomiting, n (%)	3 (5.8)	2 (3.8)	1.9 (−8.0 to +12.2)	1.000
Residual gastric volume > 200 mL, n (%)	17 (32.7)	9 (17.3)	15.4 (1.3–31.1)	0.113
Intolerance to EN, n (%)	19 (36.5)	11 (21.2)	15.4 (−2.0 to +31.6)	0.130
ICU death, n (%)	13 (25.0)	15 (28.9)	−3.9 (−13.0 to +20.5)	0.508
LOS, days	16 (10–21)	15 (9–21)	1 (−3 to +4)	0.694
Ventilation days, days	8 (5–16)	10 (6–16)	1 (−2 to +3)	0.592

Note: Data presented as median (IQR) for continuous variables and n (%) for categorical variables.

Abbreviations: ICU, intensive care unit; LOS, length of stay.

Considering death as a competing event, the intervention group had a higher but non‐significant risk of feeding intolerance (unadjusted HR 1.88; 95% CI, 0.92 to 3.80; p = 0.08; Figure 2). In the multivariable Fine–Grey model adjusted for age, sex, BMI, diabetes mellitus, SOFA score, prone position and sedative agents, the group effect was attenuated and remained non‐significant (adjusted HR 1.35; 95% CI, 0.62 to 2.92; p = 0.45; Table 3). Within the same adjusted model, BMI was identified as a protective factor against feeding intolerance (HR, 0.91 per 1‐point increase; 95% CI, 0.82 to 0.99; p = 0.044; Table 3). Higher SOFA scores were significantly associated with increased intolerance risk (HR, 1.14 per 1‐point increase; 95% CI, 1.03 to 1.27; p = 0.014; Table 3). No statistically significant effects were observed for prone positioning (HR, 1.84; 95% CI, 0.85 to 3.99; p = 0.120; Table 3) or sedative agents (HR, 3.65; 95% CI, 0.93 to 14.31; p = 0.063; Table 3).

FIGURE 2.

Feeding intolerance in the control group with routine gastric residual volume monitoring and the intervention group without routine gastric residual volume monitoring. The figure shows the cumulative incidence of enteral nutrition intolerance in both groups. Death was treated as a competing risk in the analysis of time from randomisation to intolerance and is not shown in the figure.

TABLE 3.

Factors influencing clinical outcomes in the multivariable Fine–Grey model.

	coef	HR (exp(coef))	95% CI	p value
Age	0.009	0.991	0.968–1.014	0.440
Sex_n	−0.322	0.725	0.306–1.717	0.460
BMI	−0.100	0.905	0.821–0.997	0.044
DM_n	0.428	1.534	0.653–3.601	0.330
SOFA	0.134	1.143	1.028–1.272	0.014
Sedative agents	1.295	3.650	0.931–14.312	0.063
Prone position	0.610	1.840	0.850–3.985	0.120
Group	0.298	1.347	0.621–2.921	0.450

Abbreviations: BMI, body mass index; DM, diabetes mellitus; SOFA, sequential organ failure assessment.

6. Discussion

In recent years, issues related to GRV monitoring, such as feeding interruptions and insufficient caloric intake, have received considerable clinical attention [24]. In this randomised controlled study, the intervention and control groups underwent GRV monitoring once daily at the peak versus every 4 h, respectively. No statistically significant differences in feeding intolerance were observed between groups. These findings suggest that reducing the frequency of GRV monitoring is non‐inferior to conventional monitoring with respect to feeding tolerance. The intervention did not significantly increase feeding intolerance presenting as nausea or vomiting. Conversely, reducing monitoring frequency may minimise feeding interruptions, allowing patients to receive enteral nutrition more continuously and increasing the likelihood of achieving caloric targets. Additionally, less frequent monitoring reduces nursing workload, enabling staff to complete clinical tasks more efficiently and provide better patient care.

This study demonstrates that reduced GRV monitoring frequency (24‐ vs. 4‐hourly) maintains equivalent rates of feeding intolerance. Enteral nutrition tolerance serves as both a gastrointestinal function biomarker and a disease severity indicator, with established prognostic relevance. However, controversy remains regarding the use of GRV to assess enteral nutrition intolerance, primarily due to the lack of a standardised cut‐off value. Most nurses stop enteral nutrition when GRV reaches 200–250 mL, 25% when it is ≤ 150 mL, and 12.6% when it reaches 500 mL [12]. While some studies report variations between high (350–500 mL) and low (50–150 mL) GRV thresholds, no significant differences in enteral nutrition complications were demonstrated [25]. Furthermore, there is no consensus on the diagnostic criteria for feeding intolerance. A review comparing diagnostic criteria concluded that symptoms are the most reliable reference standard for diagnosis [10], with a greater number of symptoms correlating with worse outcomes. Statistically significant symptoms include abdominal distension, absent bowel sounds, diarrhoea and 24‐h GRV > 500 mL. Clinically, it is essential to distinguish whether these symptoms are attributable to enteral nutrition or underlying disease.

Feeding intolerance, defined as vomiting and/or GRV > 200 mL, was the primary outcome in this study. Our findings indicate that reducing GRV monitoring frequency did not increase feeding intolerance incidence, consistent with Koç's randomised controlled trial (RCT) showing that GRV monitoring presence or absence had no significant impact on vomiting rates in ICU patients [26]. Accordingly, GRV monitoring frequency may be safely reduced. A systematic review of five RCTs similarly found no significant differences in pneumonia or aspiration incidence among critically ill patients with or without GRV monitoring [27, 28, 29], suggesting that routine GRV monitoring may not be necessary. Existing evidence suggests that GRV monitoring is not significantly associated with key clinical outcomes such as mortality, pneumonia or gastrointestinal complications [15, 30]. This challenges the traditional notion that frequent GRV checks are essential for patient safety. Furthermore, 4‐hourly GRV checks correlate poorly with actual gastric emptying. Studies indicate that although one‐third of enteral nutrition suspensions are attributed to feeding intolerance, only 50% of these suspensions are clinically justified [31].

This study identified high BMI as a protective factor against feeding intolerance in mechanically ventilated patients. This effect may be attributed to abundant adipose reserves buffering acute hypermetabolic demands and attenuating delayed gastric emptying, as well as adipose‐derived anti‐inflammatory mediators, such as adiponectin, which downregulate systemic inflammation and mitigate the inhibitory effects of proinflammatory cytokines on gastrointestinal motility [32, 33]. Clinically, enteral nutrition in patients with a high BMI may be initiated at a moderately higher rate with a more liberal GRV threshold, complemented by serial gastric ultrasound to monitor motility, thereby reducing unnecessary feeding interruptions.

Additionally, this study identified SOFA score as a risk factor for feeding intolerance, with higher scores correlating with increased organ dysfunction and intolerance risk. Previous studies have established mechanical ventilation and continuous renal replacement therapy as independent risk factors for feeding intolerance, consistent with findings in this study, as patients with these interventions often present with higher SOFA scores. The SOFA score is widely used in emergency, internal, surgical and ICU settings to evaluate disease severity and prognosis in patients with multiple organ dysfunction syndrome. Its dynamic monitoring capability allows for comprehensive assessment of organ function, including gastrointestinal dysfunction, which is critical to enteral feeding tolerance [34]. During systemic hypoperfusion, the gut acts as a ‘shock organ’, exhibiting villous atrophy, increased permeability and mucosal ischemia, collectively impairing digestion and absorption [35]. Mechanistically, barrier dysfunction due to inflammatory cytokines disrupts tight junctions, increasing bacterial translocation risk and manifesting as diarrhoea and abdominal distension [36, 37]. Impaired motility due to autonomic dysregulation and inflammatory mediators further delays gastric emptying and promotes retention [38]. Clinicians should exercise caution when initiating enteral nutrition in patients with high SOFA scores, preferring low‐osmolality or short‐peptide formulas and monitoring for feeding intolerance, bowel sounds and GRV when clinically indicated (e.g., in patients with suspected intolerance or high aspiration risk) [39].

Although prone positioning may theoretically reduce intra‐abdominal pressure and improve gastric emptying, our study found no significant effect on feeding intolerance, potentially due to multifactorial pathogenesis or paradoxical pressure increases from uneven abdominal compression during proning [40, 41]. However, subgroup analysis was limited by small sample size, which may have introduced bias. Regarding sedatives, evidence is mixed, with detrimental effects primarily linked to benzodiazepines, which inhibit GABAergic neurons, reduce migrating motor complexes and increase gastric retention risk [42]. In contrast, short‐acting agents or light sedation may preserve autonomic function and reduce paralytic ileus risk [43]. Multidisciplinary management should prioritise short‐acting agents with minimal accumulation while avoiding long‐acting benzodiazepines without compromising therapeutic efficacy.

For patients receiving enteral nutrition, although guidelines indicate that frequent monitoring GRV provides no patient benefit, the lack of high‐quality research evidence has led to the common clinical practice of 4‐hourly monitoring based on empirical experience. This study, utilising data from tertiary hospitals, selected feeding intolerance as the primary outcome and compared daily monitoring at the 12th hour after feeding initiation (the peak GRV period) with conventional 4‐hourly monitoring, while also analysing influencing factors. The findings validate that the guideline‐recommended approach of reducing monitoring frequency demonstrates high applicability and safety for medically critically ill patients. Hospital policies and clinical practices should accelerate the implementation of these guidelines to reduce feeding interruptions, potentially enhancing the achievement of feeding goals and alleviating nursing workload.

7. Limitations

However, this study has several limitations. Common intolerance features, such as diarrhoea, abdominal distension or aspiration events, were not evaluated. Patients with a history of underlying high‐wasting diseases were not excluded, which may have introduced bias. Additionally, the study population received varying feeding volumes based on individual disease conditions, and prokinetic drug use may have influenced outcomes. Future research should include multicentre, large‐sample and lower‐bias studies to further assess the impact of GRV monitoring frequency.

Notably, the study was originally designed as a non‐inferiority trial. We subsequently observed a relatively high rate of adverse events, likely associated with the more severe condition of the patients. Nevertheless, the analysis accounted for mortality as a competing‐risk factor affecting feeding intolerance. After adjustment, there was no significant difference in feeding intolerance incidence between the monitoring strategies.

8. Implications for Practice and Further Research

Critical care nurses should advocate for updating institutional enteral nutrition protocols to align with current evidence and guidelines, specifically by reducing GRV monitoring frequency to once daily (with an initial check at the 12‐h peak) for most mechanically ventilated patients receiving enteral nutrition. Bedside nurses play a key role in identifying patients at higher risk of feeding intolerance: those with elevated SOFA scores require vigilant monitoring for early signs of intolerance, while nurses should recognise that higher BMI may be protective and allow for more liberal GRV thresholds. By reducing GRV checks, nurses can decrease their own workload, minimise unnecessary feeding interruptions and improve the likelihood of achieving patients' caloric targets, thereby enhancing nutritional delivery and overall quality of care.

Multicentre nursing research is needed to confirm these findings across diverse ICU settings and to evaluate the impact of reduced GRV monitoring on nursing‐sensitive outcomes. Future nursing studies should explore multimodal assessment strategies that integrate clinical judgement, risk stratification and bedside tools such as gastric ultrasound, rather than relying solely on GRV. Implementation science research led by nurses is essential to identify and overcome barriers that perpetuate frequent GRV monitoring, and to develop effective educational and organisational interventions.

9. Conclusion

Compared with routine GRV monitoring every 4 h in clinical practice, monitoring once a day at the peak time after feeding initiation will not increase the feeding intolerance rate. Clinically, patients' feeding intolerance should be considered, and the frequency of GRV monitoring should be minimised (once daily if the non‐routine testing of GRV recommended by the guidelines is not possible), thereby reducing unnecessary feeding interruptions during enteral nutrition, increasing caloric intake and reducing nursing workload.

Author Contributions

Hui Zhang: writing – review and editing, writing original draft, validation, methodology, investigation, formal analysis, data curation. Yan Chen: writing – review and editing, methodology, software, investigation, formal analysis, data curation. Fan Li: resources, methodology, investigation, formal analysis. Chaokai He: methodology, investigation, data curation. Xiaorong Li: methodology, investigation, data curation. Yu'e Wang: methodology, investigation, data curation. Junping Fan: supervision, project administration, methodology, conceptualisation. Jinglan Wang: supervision, project administration, methodology, conceptualisation. Ying Xia: writing – review and editing, validation, supervision, resources, project administration, methodology, conceptualisation. Na Guo: writing – review and editing, supervision, project administration, funding acquisition. Kunrong Yu: writing – review and editing, validation, supervision, resources, project administration, methodology, investigation, funding acquisition, conceptualisation.

Funding

This study was supported by the National High Level Hospital Clinical Research Funding (No. 2025‐PUMCH‐A‐067) and the Chinese Academy of Medical Sciences (No. 2024‐I2M‐C&T‐A‐010).

Ethics Statement

At the outset, written approval was obtained from The Institutional Review Board of Peking Union Medical College Hospital (Issue: JS‐2148) to conduct this study on October 22nd, 2019. All participants or their legal representatives provided written informed consent.

Consent

Written informed consent was obtained from all participants (or their legally authorised representatives) prior to enrollment in this randomised controlled trial.

Conflicts of Interest

The authors declare no conflicts of interest.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.