Elsevier

Journal of Critical Care

Volume 33, June 2016, Pages 137-144
Journal of Critical Care

Ventilation/ARDS/VAP
Evaluation of the effect on patient parameters of not monitoring gastric residual volume in intensive care patients on a mechanical ventilator receiving enteral feeding: A randomized clinical trial

https://doi.org/10.1016/j.jcrc.2016.01.028Get rights and content

Abstract

Purpose

This study aimed to evaluate the effects of not measuring gastric residual volume (GRV) in intensive care patients on a mechanical ventilator and receiving enteral feeding on the feeding intolerance, gastroesophageal reflux (GER) risk, and nutritional adequacy.

Methods

This randomized clinical study was performed in 2 medical intensive care units of 2 university hospitals in Ankara, Turkey. The patients were randomized into 2 groups. In the group with GRV monitoring, GRV was measured 3 times a day, and the GRV threshold was accepted as 250 mL. In addition, 24-hour pH monitoring was used in this group to assess the risk of GER. In the group without GRV monitoring, GRV was not measured. The patients were followed-up for 5 days.

Results

The feeding targets were reached more quickly in the group without GRV monitoring (n = 26) with no increase in the complication rate (P < .05). No significant relationship was found between GRV and GER in the group with GRV monitoring (n = 25) (P > .05).

Conclusion

The discrepancies in GRV measurement make it unreliable for monitoring feeding intolerance and GER. The use of GRV measurements may therefore be discontinued as part of the standard care protocol in medical intensive care units.

Introduction

Gastric residual volume (GRV) measurements are routinely used to evaluate the feeding tolerance in patients receiving enteral feeding (EF) therapy in the intensive care unit (ICU). This measurement is thought to directly indicate the amount of feeding product left in the stomach, with increasing gastroesophageal reflux (GER) and aspiration risk with increasing amounts [1], [2], [3], [4]. However, there is little supportive evidence in the literature [5], [6]. The use of GRV measurements in patients receiving EF therapy in the ICU is controversial [2], [7], [8], [9].

The volume of the fluid obtained by aspirating the gastric content through an enteral tube using a syringe is called GRV [10]. However, the GRV result can be influenced by some factors such as patient position, feeding tube location, syringe size, and measurement method [11], [12]. A study has revealed that the GRV is 2 times higher on average in patients with a wide feeding tube compared with those with a narrow feeding tube [13].

Increased GRV interrupts the use of EF because it is assumed that the gastric emptying is delayed, the GER risk is increased, and the patient cannot tolerate feeding [4]. However there is little evidence in the literature on this subject [5], and the matter is controversial [14], [15], [16]. A study has revealed that GER can be seen in patients despite low GRV values [14]. There are also no commonly accepted GRV and high GRV values in the guidelines. The acceptable GRV value has been determined as 500 mL by the American Society for Parenteral and Enteral Nutrition (ASPEN) [17] and 250 to 500 mL by the Canadian Clinical Practice Guidelines [18]. Clinical procedures related to high GRV values also differ. A study on 2298 intensive care nurses has revealed that a high GRV amount requiring EF interruption was accepted as 200 mL by 36.5% of the nurses, 250 mL by 25%, and 500 mL by 12.6% [19].

The current guides for GRV measurement in ICU patients differ, and there is no consensus recommendation for the issue [1]. (1) ASPEN has recommended avoiding EF interruption when the GRV amount is less than 500 mL and if other signs of intolerance are absent, and performing the measurement every 4 hours [17]; (2) the German Society for Nutritional Medicine indicates that GRV measurement is not a reliable concept especially for internal medicine patients, and the nurses' workload can be decreased by not performing these measurements while stating that GRV measurements should be performed in the presence of vomiting [20]; (3) the Canadian Clinical Practice Guidelines reports that there is no adequate information to be able to recommend an acceptable GRV amount, but levels 1 and 2 studies suggest a GRV amount of 250 to 500 mL as acceptable [21], (4) and the European Society for Clinical Nutrition and Metabolism (provides no specific information on GRV measurement [22].

Gastric residual volume measurement is the most commonly used method to evaluate feeding tolerance in intensive care patients [19] and is therefore one of the main factors among the reasons for interrupting EF [23], [24], [25]. However, the guidelines, clinical procedures, and studies differ on how frequently the measurement should be performed and how long EF should be interrupted before the measurement [1], [26], [27].

Although it is not known when GRV first entered nursing procedures, measurements were being performed in the 1980s [24]. Nursing investigators have emphasized the importance of clarifying the matter and that there are very few guidelines that can guide nurses regarding GRV measurement [10]. They state that a nurse spends 5.25 minutes on average for a GRV measurement and the measurement both causes loss of time and increased cost. It has been reported that the time spent on the measurement could be used for nursing activities such as providing a proper position and oral care for the patient [24].

Gastric residual volume measurements are not standardized [10], [28], and it has been reported that these measurements are unnecessary because there is little supportive evidence [3], [10], [23], [26], [28] and that they do not have any positive effect on patient parameters [18], [24]. Gastric residual volume monitoring is now more traditional than based on evidence in intensive care patients [23].

We designed a randomized trial to test the hypothesis that absence of GRV monitoring was not associated with an increased incidence of feeding intolerance such as vomiting, diarrhea, abdominal distention compared with GRV monitoring in patients receiving invasive mechanical ventilation (MV), and EF. We also assumed that GRV measurement can be inadequate in estimating the GER risk and can unnecessarily cause feeding to be inadequate in cases with a high GRV.

The secondary objective of our trial was evaluating whether the absence of GRV monitoring affected EF adequacy.

Section snippets

Design

This prospective, randomized, controlled clinical study was planned to determine the effect of not monitoring GRV on the nutritional adequacy, feeding intolerance, and GER risk of ICU patients on invasive MV and who are receiving EF treatment.

Participants

This study was conducted in the adult medical ICU of 2 university hospitals in Ankara, Turkey, between March 2014 and April 2015. Ethical approval was obtained from the Clinical Trials Ethics Committee of Kecioren Training and Research Hospital (approval

Characteristics of the participants

A total of 51 patients were included in the study. The mean age was 64.9 ± 14.9 years for the 25 patients with GRV monitoring and 68.0 ± 18.0 years for the 26 patients without GRV monitoring. Females made up 60% of the group with GRV monitoring, whereas males made up 65.4% of the group without GRV monitoring. There was a statistically significant difference between the groups for the time to reach the targeted volume and the diameter of the feeding tube used (P < .05). There was no

Discussion of the findings related to feeding intolerance in the groups with and without GRV monitoring

Feeding intolerance is defined as the presence of vomiting, abdominal distention, diarrhea, and high GRV values [8], [17]. It is stated in the literature that increased GRV will lead to an increased incidence of feeding intolerance [32]. However, contradicting results are found in the relevant studies. A consistent relationship between increased GRV value and feeding intolerance incidence is not present, and the condition can also develop in patients with low GRV values. Mentec et al [15] have

Conclusion

In summary, discrepancy in GRV measurements make it unreliable for monitoring feeding intolerance and GER. Gastric residual volume measurements cause EF interruption in ICU patients leading to the inability to provide nutrition at the desired level. This study has indicated that it is possible to remove GRV measurement from the standard care in the ICU and that it would then be possible for nurses to devote more time to patient care instead of GRV monitoring and repeated measurements in the

Limitations

The small sample size is the limitation of this study. In addition, this study was conducted in an adult medical critical care unit, and the findings might therefore not reflect other critical care units. The study could be replicated in other critical care units with a larger sample size.

Funding and financial disclosures

Gulhane Military Medical Academy Scientific Research Council has funded the research as a part of project no. AR-2014/19.

Conflict of interest

There is no personal conflict of interest.

Acknowledgments

We are grateful to the patients' relatives who allowed their patient to participate in this study. We also thank Dr Cengizhan ACIKEL and Dr Gulcan BAGCIVAN for the statistical analysis of our study.

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