Effects of abdominal massage on gastrointestinal function in ICU patients: a meta-analysis

The inclusion criteria were as follows. Randomized controlled trials (RCTs) were included. The language was limited to Chinese and English.

The following patients were excluded: patients with no abdominal radiotherapy and abdominal surgery performed in the past 6 weeks; patients with abdominal contraindications, such as abdominal tumor, peritonitis, ascites, and ileus; patients with congenital malformation, such as congenital heart disease and abnormal digestive tract; and neonates fed with gastrostomy tubes.

Participants were patients in the ICU.

The experimental group received abdominal massage on the basis of the same intervention measures as the control group. The control group received conventional care.

Gastric residue, abdominal circumference, the incidence of gastric retention, bloating, and vomiting were assessed.

We carried on a comprehensive search of the literature in five English databases: (PubMed, Web of Science, the Cochrane Library, Embase, and AMED) and four Chinese databases (CBM, CNKI, Wanfang, and VIP), which have been searched from their establishment to November 2018.

The Chinese search strategy was “ComaICUN ICU Intensive care unit premie low birth weight infant” AND “swaddle swaddling”. The English search strategy was “abdominal massage*”. We used the following subject words, free words, and Boolean logic operators when searching. Computer retrieval was the main method, supplemented by manual retrieval. In the retrieved literature, the second extended retrieval was carried out to avoid the omission of literature, and the quality evaluation of the included literature was carried out.

There were two reviewers screened independently according to the inclusion and exclusion criteria. From each included study, data were extracted independently. Study characteristics (eg, author and year), study design, sample size, description of interventions, and indexes of assessed outcomes were sorted using a data extraction form. If two researchers disagree on the quality of the study, a third nursing professor with a PhD arbitrated.

Meta-analysis was conducted using the RevMan 5.3 software. When meta-analysis was conducted for continuous variables, data were described and expressed as mean difference (MD) or standard mean difference (SMD) with 95% confidence interval (CI). If significant heterogeneity did not exist among studies (I² ≤ 50%, P ≥ 0.1), a fixed effect model was established in the meta-analysis. If significant heterogeneity existed among studies (I² > 50%, P < 0.1), the source of the heterogeneity was analyzed. If only statistical heterogeneity was observed among the studies, without clinical heterogeneity, a randomized effect model was constructed. Descriptive analysis was conducted if the heterogeneity was too obvious and the source could not be determined.

The basic characteristics of the included studies are given in Table 1. According to the Cochrane risk of bias estimation, generation of allocation sequence in every trial is mentioned.8 Among the nine included articles the quality was B. Because the intervention in this study was abdominal massage, the participants could not be blinded (excluding coma patients and premature infants). So, it was rated as high risk of bias (Table 2).

A total of nine articles were included. The quality grades of all articles were B, and the overall quality was moderate. This may be related to the inconsistency of the randomized design of the included studies and the lack of attention to blindness. One of the included studies13 was grouped by the random number method. Although randomization was mentioned in the other studies,4, 6,9, 10, 11, 12, 14, 15 the specific grouping method was unclear. One study6 used allocation hiding. Because the outcome indicators were objective, it had little influence on the evaluation of the results, although the outcome evaluators were not blinded. Therefore, they were still judged as “low risk”. In addition, the baseline included in the study was comparable.

Six articles in this study showed that abdominal massage can reduce the incidence of abdominal distension. At the same time, the results of this study showed that abdominal massage could not reduce the abdominal circumference in the ICU when the intervention period was <7 days, and it could reduce the abdominal circumference in the ICU when the intervention period was equal to 7 days. Patients in the ICU often need a long period of bed rest due to their serious illness, so their peristaltic function is poor and the incidence of adverse reactions is high. Abdominal massage is a safe, convenient, economical, simple, and effective non-drug nursing method.16 It can reduce the incidence of abdominal distension by changing the intra-abdominal pressure and accelerating the gastrointestinal peristalsis to produce mechanical reflex effect on the intestinal tract.17, 18, 19 At the same time, abdominal massage can stimulate the skin sense of touch and pressure receptors produce sympathetic stimulation to promote gastrin secretion to promote gastric peristalsis and reduce abdominal distention.20

Seven literatures included in this study showed that abdominal massage can reduce gastric residual in ICU patients. Three of the articles showed that abdominal massage can reduce gastric retention rate. Multiple studies have found an incidence of GRV of 28.2%,21 29%,22 32%23, and 39%24 in ICU patients. GRV is an important factor affecting gastric emptying speed in ICU patients.6 Controlling and reducing GRV is an important measure to improve the nutritional status and reduce complications and the incidence of malnutrition in ICU patients.25, 26 Abdominal massage had a good effect to reduce the amount of gastric residue and reduce the incidence of gastric retention. It plays an important role in the intake and absorption of nutrients in patients too.

Six articles were included in this study that showed that abdominal massage can reduce the incidence of vomiting. Vomiting is one of the most serious complications in ICU patients, which increased the risk of aspiration pneumonia.11 The causes of vomiting are varied, but delayed gastric emptying is one of the main causes. Abdominal massage stimulates the vagus nerve and increases intestinal motility to prevent delayed gastric emptying. Abdominal massage has a mechanical reflex effect on the gut that increases peristalsis and promotes gastric emptying, which further prevents vomiting.3 In clinical practice, abdominal massage, as a nursing method to help patients accelerate gastric emptying, has a promotion value for preventing the occurrence of vomiting in patients.27