Optimal approach to prohibit drinking water prior to EGE in middle-aged and elderly individuals

Abstract

Background

Electronic gastroscopic examination (EGE) is the most effective and reliable method for the screening and diagnosis of upper gastrointestinal diseases. Prolonged prohibition of drinking water before EGE may lead to discomfort in patients.

Aim

To identify whether water-deprivation duration can be safely minimized in unsedated EGE for middle-aged/elderly patients without gastric emptying disorders.

Methods

A total of 252 middle-aged and elderly patients who underwent unsedated EGE at the Shaanxi Cancer Hospital endoscopy center were randomly assigned to three groups: the control group (drinking 200 ml of warm water 6 h before EGE), Experimental group A ( 200 ml of warm water 2 h before EGE), and Experimental group B ( 200 ml of warm water 1 h before EGE). Prior to EGE, patient discomfort and anxiety levels were assessed 15 min beforehand. Residual gastric volume (RGV) and clarity of the visual field (EVFC) during EGE were also evaluated.

Results

The Experimental groups showed lower scores for thirst, dryness of the mouth, nausea, vomiting, and weakness than the control group. No significant intergroup differences were observed in EVFC and RGV qualified rates among the two experimental groups and the control group. However, Experimental group B showed an unfavorable downward trend in RGV qualified rate. No adverse events such as aspiration occurred in either group.

Conclusion

For middle-aged and elderly patients without gastric emptying disorders, drinking 200 ml of warm water 2 h prior to EGE is recommended. This strategy improves patients’ comfort and mood, and maintains normal EVFC and RGV. Even though 1-hour water intake results in no statistically significant differences in RGV and EVFC, it presents an unfavorable trend of reduced RGV qualified rate.

Introduction

It is recommended that individuals aged ≥ 40 years undergo gastric cancer screening every 2 years [1]. Electronic gastroscopy is the most effective and reliable method for the screening and diagnosis of upper gastrointestinal diseases [2, 3]. Our center’s institutional protocol requires a minimum fasting period of 6 h prior to EGE, aligning with widely recognized safety standards in gastrointestinal endoscopy guidelines [4–6].

The purpose of fasting before EGE is to clear the contents of the stomach, ensuring optimal visibility during the procedure while minimizing the risk of reflux and aspiration, thereby enhancing patient safety. Unfortunately, patients often face excessively long fasting periods; some may endure nearly 20 h without food prior to the operation [7]. Extended fasting can cause hunger, increase sympathetic nerve activity, and result in irritability, anxiety, and tension [8]. These may increase discomfort during EGE, heighten sensitivity to pain, elevate blood pressure and heart rate, reduce cooperation with the medical staff, and impose challenges in achieving sedation or relaxation. These psychological and physiological responses can also complicate the procedure, prolong recovery times, and negatively impact overall diagnostic accuracy and patient experience.

Notably, modern perioperative protocols such as the Enhanced Recovery After Surgery (ERAS) guidelines recommend reduced fasting durations, permitting clear liquids up to 2 h before procedures involving sedation or anesthesia [9]. Although the routine application of this standard prior to EGE remains limited in clinical practice, other studies have explored the possibility of reducing the fasting period without compromising the quality and safety of examinations [10, 11]. Recent findings suggest that shorter fasting durations may be sufficient in specific cases, provided patients adhere to dietary restrictions and consume only clear liquids during the allowed timeframe. Such adjustments could improve patient comfort and compliance, thereby enhancing the overall screening experience while maintaining diagnostic accuracy and safety standards [11–14].

This study aimed to determine whether the duration of water deprivation could be minimized to 2 h–1 h without compromising examination safety and visual clarity in patients undergoing unsedated EGE.

Patients and methods

Patients

This study included 252 middle-aged and elderly patients who underwent unsedated EGE at the Endoscopy Center of the Shaanxi Provincial Tumor Hospital between January 2024 and June 2024. Informed consent was obtained from all the patients. The patients were randomly divided into control group ( 200 ml warm water 6 h before EGE), experimental group A ( 200 ml warm water 2 h before EGE), and experimental group B ( 200 ml warm water 1 h before EGE).

The inclusion criteria for this study were as follows: age between 40 and 70 years, unsedated EGE performed at the discretion of the physician, voluntary participation, and provision of informed consent. The exclusion criteria were obesity, suspected gastroesophageal reflux disease or upper gastrointestinal tumor, dysphagia, history of gastric retention, pyloric obstruction, intestinal obstruction, or esophageal and gastric surgery.

Methods

Randomization

The random allocation sequence was generated by an independent statistician using the random number generator function in SPSS software (version 26.0, IBM Corp.), with a 1:1 allocation ratio. The personnel evaluating the patients before the examination and the endoscopist were blinded to the patient allocation.

Prohibited diet guidance

All the patients were scheduled to undergo EGE at various time points. Prior to EGE, a nurse provided detailed explanations regarding the purpose and significance of the different methods used to restrict water consumption. This discussion took place one day before the scheduled procedure. Written informed consent was obtained from all the patients. Additionally, patients were instructed to follow a low-fat, low-oil, low-residue diet one day before the EGE. All participants fasted for at least 6 h before the EGE. They were also advised to keep a record of the timing, volume, and type of water consumed to ensure compliance with the fasting and water restriction guidelines for the procedure.

Data collection and observation indicators

Patient discomfort, including thirst, dry mouth, hunger, nausea, vomiting, and fatigue, was assessed by nurses using the visual analog scale (VAS) 15 min prior to EGE [15]. VAS is a 10-point scale, with each score corresponding to the following levels of discomfort: 0, no discomfort, 1–3 for mild discomfort, 4–6 for moderate discomfort, and 7–10, severe discomfort.

The Zung Self-Rating Anxiety Scale (SAS) was used to assess anxiety levels [16]. The scoring system utilizes a four-point scale that primarily evaluates the frequency of symptoms experienced by individuals. A score of “1” indicates no or very infrequent occurrences; “2” signifies occasional symptoms; “3” denotes frequent symptoms; while “4” reflects symptoms occurring most or all of the time. The total score was calculated by summing the scores across 20 items, which was then multiplied by 1.25 to yield a standard score. A standard score below 50 is considered normal, a score between 50 and 59 indicates mild anxiety, a score between 60 and 69 represents moderate anxiety, and a score exceeding 70 suggests severe anxiety [6].

During EGE, the endoscopist conpletely aspirated the residual gastric juice and assessed the RGV. Gastric juice volume was classified into three grades: small (< 50 mL), medium (50–100 mL), and large (> 100 mL). Among these categories, small and medium amounts were considered to qualify as RGV. Endoscopists assessed the endoscopic visual field clarity (EVFC) and categorized it as clear, unaffected, or affected. A clear or unaffected EVFC was considered qualified (Fig. 1).

Fig. 1.

Scores of EVFC. A clear vision, B unaffected vision, C Affected vision

Statistical methods

All statistical analyses were performed by a qualified statistician using SPSS version 26.0. All continuous variables (including age, VAS discomfort scores and SAS scores) did not follow a normal distribution. The Kruskal-Wallis H test was used for overall comparison among the three groups, and the Mann-Whitney U test with Bonferroni correction was applied for subsequent pairwise comparisons.

For categorical variables, the Pearson’s chi-square test was used to compare gender distribution across the three groups. For 2 × 2 contingency tables of RGV and EVFC, Fisher’s exact test was adopted because several cells had expected frequencies less than 5.

A two-sided P < 0.05 was defined as statistically significant.

No major changes to methods after trial commencement were made.

Results

A total of 252 patients, including 132 males and 120 females with an average age of 55.60 ± 9.045 years, were included in the study. No aspiration or other severe adverse events occurred during the examination. Baseline demographic characteristics were compared among the three groups. There were no significant differences in gender and age across groups (P > 0.05), indicating acceptable baseline comparability (Table 1).

Table 1.

Baseline characteristics of the three groups of patients

Group	n	Gender (Male/Female)	Age (years)
Experimental group A (2 h water restriction)	85	46/39	54.00 (47.00, 62.00)
Control group	87	45/42	57.00 (49.00, 66.00)
Experimental group B (1 h water restriction)	80	41/39	55.00 (47.00, 62.00)
χ2/ H	-	0.159	2.468
P	-	0.924	0.291

Age is presented as median (P25, P75) and analyzed by Kruskal-Wallis H test; Gender was compared using the χ² test

All continuous variables including subjective discomfort scores and SAS scores did not follow a normal distribution (all P < 0.05 for normality tests). Thus, Kruskal-Wallis H test was used for overall comparison among three groups, and Mann-Whitney U test with Bonferroni correction was applied for pairwise comparisons. The adjusted significance level for pairwise comparison was set at α = 0.0167.

Compared with the control group, Experimental group A (2 h water restriction) had significantly lower scores of thirst, dry mouth, nausea, vomiting, physical weakness and SAS (all P < 0.0167). No significant difference in hunger score was found between the control group and Experimental group A (P = 0.122) (Table 2).

Table 2.

Comparison of the discomfort score and SAS score before examination in Experimental group A and control group of patients(X ± s) Unit: points

Index	Control group (n = 87)	Experimental group A (n = 85)	Z	P
Dry mouth	2.00 (2.00, 3.00)	2.00 (1.00, 2.00)	-5.697	< 0.001
Thirst	3.00 (2.00, 3.00)	2.00 (1.00, 2.00)	-6.789	< 0.001
Hunger	2.00 (2.00, 3.00)	2.00 (2.00, 2.00)	-1.548	0.122
Nausea	1.00 (0.00, 1.00)	0.00 (0.00, 1.00)	-8.407	< 0.001
Vomiting	1.00 (0.00, 1.00)	0.00 (0.00, 0.00)	-5.546	< 0.001
Physical weakness	1.00 (0.00, 1.00)	0.00 (0.00, 0.00)	-5.587	< 0.001
SAS score	52.50 (48.00, 57.00)	43.75 (40.00, 47.00)	-9.290	< 0.001

Data are presented as median (P25, P75); Mann-Whitney U test with Bonferroni correction, α = 0.0167

SAS Self-Rating Anxiety Scale

As shown in Table 3, Experimental group B (1 h water restriction) obtained significantly lower scores in thirst, dry mouth, hunger, nausea, vomiting, physical weakness and SAS than the control group (all P < 0.0167).

Table 3.

Comparison of preoperative discomfort scores and SAS scores between control group and Experimental group B

Index	Control group (n = 87)	Experimental group B (n = 80)	Z	P
Dry mouth	2.00 (2.00, 3.00)	1.00 (1.00, 2.00)	-9.376	< 0.001
Thirst	3.00 (2.00, 3.00)	1.00 (1.00, 2.00)	-8.099	< 0.001
Hunger	2.00 (2.00, 3.00)	2.00 (1.00, 2.00)	-3.893	< 0.001
Nausea	1.00 (0.00, 1.00)	0.00 (0.00, 0.00)	-8.476	< 0.001
Vomiting	1.00 (0.00, 1.00)	0.00 (0.00, 0.00)	-5.658	< 0.001
Physical weakness	1.00 (0.00, 1.00)	0.00 (0.00, 0.00)	-6.486	< 0.001
SAS score	52.50 (48.00, 57.00)	40.00 (37.00, 44.00)	-10.297	< 0.001

Data are presented as median (P25, P75); Mann-Whitney U test with Bonferroni correction, α = 0.0167

SAS Self-Rating Anxiety Scale

The SAS scores of both two experimental groups were below 50 points, and were significantly lower than those of the control group (Fig. 2).

Fig. 2.

SAS scores of 3 groups of patients

We further evaluated RGV and EVFC, which were presented as categorical data and analyzed by the χ2 test. No significant differences in the qualified rates of RGV and EVFC were observed between Experimental group A and the control group (both P > 0.05). No aspiration events occurred in either group (Table 4).

Table 4.

Comparison of RGV and EVFC between control group and Experimental group A

Group	n	RGV [n (%)]		EVFC [n (%)]
		Unqualified	Qualified	Unqualified	Qualified
Control group	87	1 (1.1)	86 (98.9)	1 (1.1)	86 (98.9)
Experimental group A	85	2 (2.4)	83 (97.6)	4 (4.7)	81 (95.3)
P	-	0.618		0.208

Fisher’s exact test was used for comparison

RGV Gastric residual volume, EVFC Endoscopic visual field condition

No significant differences in the qualified rates of RGV and EVFC were observed between Experimental group B and the control group (both P > 0.05). No aspiration events occurred in either group. Although no statistically significant difference was observed (P = 0.056), the lower RGV qualified rate in Group B still suggests a potential increased risk of gastric retention and aspiration (Table 5).

Table 5.

Comparison of RGV and EVFC between control group and Experimental group B

Group	n	RGV [n (%)]		EVFC [n (%)]
		Unqualified	Qualified	Unqualified	Qualified
Control group	87	1 (1.1)	86 (98.9)	1 (1.1)	86 (98.9)
Experimental group B	80	6 (7.5)	74 (92.5)	2 (2.5)	78 (97.5)
P	-	0.056		0.607

Fisher’s exact test was used for comparison

RGV Gastric residual volume, EVFC Endoscopic visual field condition

Between Experimental group A and Experimental group B, no significant differences were found in the qualified rates of RGV and EVFC (both P > 0.05). No adverse events such as aspiration occurred in both groups (Table 6).

Table 6.

Comparison of RGV and EVFC between Experimental group A and Experimental group B

Group	n	RGV [n (%)]		EVFC [n (%)]
		Unqualified	Qualified	Unqualified	Qualified
Experimental group A	85	2 (2.4)	83 (97.6)	4 (4.7)	81 (95.3)
Experimental group B	80	6 (7.5)	74 (92.5)	2 (2.5)	78 (97.5)
P	-	0.158		0.683

Fisher’s exact test was used for comparison

RGV Gastric residual volume, EVFC Endoscopic visual field condition

No modifications were made to the trial protocol or outcomes after study initiation. No additional subgroup analyses or adjusted analyses were performed in this study.

Discussion

Disadvantages of long prohibited drinking water time on patients

Extended fasting can cause hunger, increase sympathetic nerve activity, and result in irritability, anxiety, and tension [8]. These may increase discomfort during EGE, heighten sensitivity to pain, elevate blood pressure and heart rate, reduce cooperation with the medical staff, and impose challenges in achieving sedation or relaxation.

These psychological and physiological responses can also complicate the procedure, prolong recovery times, and negatively impact overall diagnostic accuracy and patient experience. Shortening the duration of water deprivation can help alleviate thirst, dry mouth, hunger, nausea, vomiting, weakness, discomfort, and anxiety, thereby improving patient compliance with EGE. Prolonged fasting can also reduce the absorption of glucose, amino acids, and fatty acids, potentially leading to dehydration and electrolyte imbalance [17]. These effects directly impact vital sign stability and may hinder the smooth progress of EGE [18]. Prolonged fasting may also result in bile reflux, compromising the accuracy of endoscopic diagnosis and leading to frequent misdiagnoses of pathological bile reflux [19].This is because of the negative effects associated with prolonged fasting. Therefore, it is crucial to minimize the prohibited drinking period before EGE. Recent studies suggest that allowing patients to drink clear fluids up to two hours before the procedure does not increase complications such as aspiration or delayed gastric emptying and may improve patient comfort and satisfaction [11, 12]. Clear fluids, including water, are rapidly emptied from the stomach, making them safe for consumption close to the procedure time. Additionally, appropriate guidelines can help ensure adequate preparation without unnecessarily extending fasting periods, striking a balance between safety and patient-centered care. Moving toward evidence-based fasting protocols can enhance both the accuracy of endoscopic evaluations and overall patient experience.

Causes of long-duration of prohibited drinking water

Although the recommended fasting time before undergoing esophagogastroduodenoscopy (EGD) is 6 h, patients often find themselves fasting for a significantly longer duration. Several factors contribute to these extended fasting periods: (1) patients frequently lack adequate awareness of the restrictions regarding water consumption before the procedure, leading to poor compliance. (2) Delays in the endoscopic schedule: Unforeseen circumstances such as prolonged previous examinations or emergencies often result in patients fasting beyond the recommended time. (3) Miscommunication between healthcare providers and patients: Unclear instructions concerning the timing and nature of fasting frequently lead to confusion, prompting patients to extend their fasting periods unnecessarily. As a result, prolonged fasting intervals can cause discomfort, dehydration, and potentially adverse effects, particularly in vulnerable populations, such as the elderly or those with chronic conditions. Addressing these issues necessitates enhanced patient education, more efficient scheduling practices, and clearer communication to ensure adherence to recommended fasting guidelines.

Feasibility of shortening the duration of prohibited drinking water

Numerous specialized departments have conducted research on dietary restrictions at various times, yielding significant results [14, 20–23]. This study found that drinking 200 ml warm water 1–2 h before the examination can reduce the discomfort of thirst, dry mouth, hunger, nausea, vomiting, and weakness, and can effectively relieve the anxiety of patients before the examination. Drinking 200 ml warm water 1–2 h before EGE had no significant effect on the EVFC. However, patients who drank 200 ml warm water 1 h before the EGE showed a downward trend in RGV qualified rate, implying a potential risk of reflux and aspiration. Therefore, it is more recommended to drink 200 ml of warm water 2 h prior to EGE. Drinking warm water at this specific time not only provides comfort, but also ensures patient safety by minimizing the risk associated with unfavorable changes in RGV. Further studies focusing on optimizing preprocedural hydration strategies may help refine the guidelines and enhance patient experience during examinations.

Analysis of the causes of RGV elevation in experimental group B patients

Ultrasonographic emptying studies

Gastric emptying is influenced by the volume of fluid ingested and the osmotic pressure of the beverage [24–26]. The transit time of fluids containing fat, such as milk, is slower compared to clear fluids like glucose solution, necessitating a minimum fasting period of three hours following milk consumption [27]. Thomas et al. reported a delay in gastric emptying after the ingestion of apple juice or glucose solution, in contrast to water. In their study, complete gastric emptying of water occurred within 60 min, whereas returning to pretrial gastric size after consuming apple juice or glucose solution required 90 min.

Biphasic liquid emptying pattern and age-related delays

Theodora et al. indirectly investigated the gastric emptying of 240 ml of water in healthy older and younger volunteers using caffeine. Statistical analysis of the AUC ratios of salivary caffeine concentrations revealed no significant differences between the two age groups in both fasted and fed states [28]. One volunteer from the older population group exhibited a significant delay in the onset of salivary caffeine concentrations. A potential explanation for this could be the presence of gastroparesis, leading to water retention in the stomach and a slower gastric emptying rate [29]. While these findings are valuable, their applicability is limited as they only include healthy older individuals, rendering the results not fully representative of the entire older demographic.

However, age-related physiological changes in the gastrointestinal tract render the older population particularly susceptible to chronic gastrointestinal diseases. Notable examples include gastroparesis [30], gastric ulcers, atrophic gastritis, and peptic ulcer disease [31]. Furthermore, medications frequently prescribed to older individuals, such as opiates, levodopa, and anticholinergics, may lead to delayed gastric emptying [32].

Our research primarily focuses on middle-aged and elderly individuals aged 40 to 70 years. Although we excluded subjects with obesity, suspected gastroesophageal reflux disease or upper gastrointestinal tumor, dysphagia, history of gastric retention, pyloric obstruction, intestinal obstruction, or esophageal and gastric surgery, some participants may still experience delayed gastric emptying. Although no aspiration incidents were observed in any patients, the findings suggest the trend toward a lower RGV qualification rate in Group B reflects physiological variability in gastric emptying, particularly in older adults where 1-hour prohibit drinking water prior EGE may be inadequate despite clear liquids’ nominal rapid clearance.

Limitations

This single-center study may limit the generalizability of our findings across diverse clinical settings. While we demonstrated that consuming 200 ml of water 1–2 h prior to gastroscopy reduces discomfort without compromising endoscopic visibility, we did not investigate finer variations, such as fasting intervals (e.g., 3–5 h), smaller fluid volumes (< 200 ml), and alternative fluid types (e.g., electrolyte solutions). Second, the present study only focused on patient subjective comfort and endoscopic visual field clarity. We did not evaluate the potential impacts of different water deprivation regimens on endoscopic procedure time and endoscopist satisfaction, which are clinically important indicators for optimizing standardized pre-gastroscopy preparation protocols. Third, data regarding patients’ underlying chronic diseases and long-term medication history were not collected in this trial. These factors are known to influence gastric emptying function and preoperative anxiety levels, which may act as potential confounding variables. Although these limitations do not undermine the validity and reliability of our primary conclusions, they highlight valuable directions for future high-quality, multi-center trials with rigorous factorial designs to further refine the optimal preoperative water deprivation strategy for middle-aged and elderly patients.

Conclusion

For middle-aged and elderly patients without gastric emptying disorders, it is advisable to drink 200 ml of warm water 2 h before the EGG. This practice enhances patient comfort and reduces anxiety, without negatively impacting EVFC and RGV. Although 1-hour preoperative intake of the same volume of warm water yields no statistically significant changes in EVFC and RGV, it shows a declining trend in RGV qualified rate and thus implies a potential clinical risk.

Authors’ contributions

Yong Chen contributed to conceptualization, data curation, writing – original draft, writing – review & editing, fund support; Shan-Ping Huang contributed to conceptualization, supervision, visualization, writing – original draft; Li Gang and Chen Peng contributed to writing – original draft, performed the article search, writing – review & editing; Shen-Bo Fu contributed to data curation, writing – review & editing; fund support; Ya-Li Cheng contributed to data management, and has carried on the professional statistical analysis.

Funding

This work was supported by the China Digestive Early Cancer Physicians Joint Growth Program Project (GTCZ-2020-SX-61-0001); Shaanxi Province Key R&D Program General Project–Social Development Field (2024SF-YBXM-121); Xi’an Science and Technology Plan Project(24YXYJ0184); Shaanxi Cancer Hospital National Natural Science Foundation Incubation Project (SCB2417); Shaanxi Cancer Hospital National Natural Science Foundation Incubation Project (SC212014).

Data availability

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

This study was conducted in accordance with the Declaration of Helsinki and approved by the Ethical Committee of Shaanxi Province Cancer Hospital Hospital (approval number: 2024-47). Informed consent was obtained from all subjects involved in this study.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.