Evaluation of delivery of enteral nutrition in mechanically ventilated Malaysian ICU patients
Evaluation of delivery of enteral nutrition in mechanically ventilated Malaysian ICU patients
Keng F Yip 0
Vineya Rai 0
Kang K Wong 0
0 Department of Anaesthesiology, Faculty of Medicine, University of Malaya , 50603 Kuala Lumpur , Malaysia
Background: There are numerous challenges in providing nutrition to the mechanically ventilated critically ill ICU patient. Understanding the level of nutritional support and the barriers to enteral feeding interruption in mechanically ventilated patients are important to maximise the nutritional benefits to the critically ill patients. Thus, this study aims to evaluate enteral nutrition delivery and identify the reasons for interruptions in mechanically ventilated Malaysian patients receiving enteral feeding. Methods: A cross sectional prospective study of 77 consecutive patients who required mechanical ventilation and were receiving enteral nutrition was done in an open 14-bed intensive care unit of a tertiary hospital. Data were collected prospectively over a 3 month period. Descriptive statistical analysis were made with respect to demographical data, time taken to initiate feeds, type of feeds, quantification of feeds attainment, and reasons for feed interruptions. There are no set feeding protocols in the ICU. The usual initial rate of enteral nutrition observed in ICU was 20 ml/hour, assessed every 6 hours and the decision was made thereafter to increase feeds. The target calorie for each patient was determined by the clinician alongside the dietitian. The use of prokinetic agents was also prescribed at the discretion of the attending clinician and is commonly IV metoclopramide 10 mg three times a day. Results: About 66% of patients achieved 80% of caloric requirements within 3 days of which 46.8% achieved full feeds in less than 12 hours. The time to initiate feeds for patients admitted into the ICU ranged from 0 - 110 hours with a median time to start feeds of 15 hours and the interquartile range (IQR) of 6-59 hours. The mean time to achieve at least 80% of nutritional target was 1.8 days 1.5 days. About 79% of patients experienced multiple feeding interruptions. The most prevalent reason for interruption was for procedures (45.1%) followed by high gastric residual volume (38.0%), diarrhoea (8.4%), difficulty in nasogastric tube placement (5.6%) and vomiting (2.9%). Conclusion: Nutritional inadequacy in mechanically ventilated Malaysian patients receiving enteral nutrition was not as common as expected. However, there is still room for improvement with regards to decreasing the number of patients who did not achieve their caloric requirement throughout their stay in the ICU.
Enteral nutrition; Gastric residual volume; Interruptions to feeding
Nutrition in the Intensive Care Unit (ICU), though
seemingly elementary, presents with varied number of
challenges. Patients admitted in the ICU are often
multidisciplinary and heterogeneous in terms of general
condition, severity of illness and specific needs. Differences in
opinions amongst care providers add to the vast variation
in debatable topics, especially in nutritional therapy. In
critically ill patients, enteral nutrition is preferred in the
majority of cases because of its ease of use, reduced cost
and lower risk of catheter-related septic complications .
However, inadequate nutritional intake in enterally fed
patients remains a global issue [2,3]. A recent study by
Miroslav , revealed that 26% of feeding interruptions in
a Boston teaching hospital were avoidable and as such led
to a 30% increase in length of stay in the ICU and a 50%
increase length of hospital stay in patients. Several factors
that contribute to inadequate nutritional delivery include,
but not restricted to, gastrointestinal intolerance,
displacement or obstruction of the feeding tube, therapeutic
procedures, airway management or nursing procedures .
The current ICU in our tertiary care institution does
not have an Enteral Nutrition Protocol and feeding has
been administered as ordered by the care provider.
Current findings have already shown that the presence
of an enteral feeding protocol is associated with
significant improvements in nutritional practice [6,7]. As our
current ICU does not have a standard feeding protocol,
we felt that nutritional goals such as the time to initate
and time to achieve full feeds would be slow to be met
and there will be a high number of feeding
interruptions. To date, no studies have reported on the nutritional
status of critically ill adult Malaysian patients on
mechanical ventilation receiving enteral nutrition. Thus, this study
aims to evaluate enteral nutrition delivery and identify
the reasons for interruptions in mechanically ventilated
Malaysian patients receiving enteral feeding.
A cross sectional prospective study was conducted in an
open 14-bed general intensive care unit at a tertiary care
hospital for a period of three months. Patients were
included in the study if they were above 18 years of age,
require mechanical ventilation, expected to stay for at
least 24 hours in the ICU and received enteral nutrition
at any time while being ventilated. Patients were excluded if
enteral nutrition was clinically contraindicated.
Contraindications to enteral feeding includes, exclusively: (1) severe
hemodynamic instability; (2) bowel obstruction; (3) severe
protracted ileus; (4) major upper gastrointestinal bleeding;
(5) intractable vomiting or diarrhoea; and (6)
gastrointestinal ischaemia. The patients were individually observed
until discontinuation of enteral feeding, discharged from
the ICU or death. This study was approved by Medical
Ethics Committee of University Malaya Medical Centre,
Lembah Pantai 59100 Kuala Lumpur. Consent was waived
as this is an observational study.
Our primary endpoint was the time to achieve full feeds
and secondary endpoints were the time to initiate feeds
and reasons for interruption to feeding.
A multidisciplinary team which included an intensivist,
registrars, registered nurses and dieticians were
responsible for decisions related to patient care, time of insertion
of feeding tube, initiation of enteral feeds, amount of feeds
to be delivered and interruptions. Demographic data, time
of admission, time of initiation of prescribed feeds, type of
enteral formula, daily calories delivered, reasons of
interruptions, amount of gastric residual volume, development
of aspiration or infection complication rates and simplified
acute physiology score (SAPS) II were recorded.
Energy intake was calculated using a goal of 25 kcal/
kg/day. Patients weight was determined using a scale or
ideal body weight if actual body weight could not be
determined. If a patient's current body weight is greater than
120% of his ideal body weight, an adjusted body weight
was used for the calculation:
Adjusted body weight = (current body weight ideal
body weight) 0.25 + ideal body weight.
SAPS II was calculated for each patient at the time of
enrolment. On each subsequent study day, the investigator
included recorded data of the previous 24 hours.
Statistical analyses were performed using the Statistical
Package for the Social Sciences, Version 17.0 (SPSS Inc.,
Chicago, IL, USA). A p value of < 0.05 was considered
to be statistically significant. A descriptive analysis was
performed for the data collected. Continuous variables
were summarized using means and standard deviations.
A total of 77 patients who fulfilled the inclusion criteria
were recruited in this study. The patients demographic
characteristics are shown in Table 1. Mean weight of the
sample population obtained was 68.2 kg, with the mean
weight of female and male patients being 63.49 kg (BMI
26.2) and 70.87 kg (BMI 24.7) respectively. A mean
SAPS score of 40 was documented in patients who
remained in the ICU after 24 hours. Patients were fed
with Glucerna, Nepro, Osmolite, Peptamen or Pulmocare.
The time taken to initiate enteral feeding was between 0
and 110 hours. The median time to initiate was 15 hours
(IQR 659 hours). The mean time of patients who
received full feeds was 1.8 days 1.5 days. Twelve out of the
77 patients (15.6%) did not achieve full feeds over their
stay in the ICU while 36 patients achieved full feeds within
Table 1 Patients characteristics
Age, mean (SD), years
Weight, mean (SD), kg
SAPS II, range (SD)
Time to initiation of Enteral Feeding
after ICU admission, median (IQR) hours
Days to full feed, mean (range), days, n = 65
Value, N = 77
12 hours of ICU admission (Table 2). Further analysis
showed that 66% patients achieved 80% of caloric
requirements within three days in ICU. During this period,
interruptions to feeding were documented for all recruited
patients. An interruption of one hour or more was
considered significant and the reason for interruption was noted.
Only 16 out of the 77 patients (20.7%) did not have any
interruptions to feeds while the rest had one or more
feeding interruptions. Out of 72 interruptions encountered
during the study, 32 of them were due to clinical procedures/
interventions on the patients (Table 3). These included
planned extubations, tracheostomies, surgical interventions
or radiological imaging. The rest were due to perceived
high GRV by the attending clinician. There were no cases
of aspirations reported.
To the best of our knowledge, this is the first study to
evaluate the delivery of enteral nutrition and the reasons
for interruption in critically ill Malaysian patients
receiving mechanical ventilation. The patients admitted to the
ICU in our study generally reflected the Malaysian
Majority were Malay (45.5%), followed by Chinese
(28.6%) and Indian (20.8%). The European Society for
Clinical Nutrition and Metabolism (ESPEN)
recommends caloric intake of 2025 kcal/kg/day during the
catabolic phase and up to 25-30 kcal/kg/day during the
anabolic phase . The American Society for Parenteral
and Enteral Nutrition (ASPEN) similarly advocates the
energy requirement for critically ill adult to be 25
30 kcal/kg/day . Although one study showed an increase
in requirement in the second week of illness , there is
not enough evidence to validate its use in this study.
Stapleton et al. showed a positive association between
moving closer to caloric goals and better clinical outcome
. Failure to achieve > 25% of caloric goals may increase
the risk of nosocomial bloodstream infections [11,12].
About 47% of patients achieved the full caloric
requirement within the first 12 hours of ICU admission.
This suggests that almost half of our patients achieved
full feeds in less than 24 hours. At three days, 66% of
the patients achieved their full caloric requirements. A
study by Kim et al.  on the adequacy of early enteral
nutrition in Korean adult patients found that about
twothirds of their patients failed to meet 90% of their energy
requirements during the first four days after initiation of
Table 2 Time taken for patients to achieve full feeds
More than 12 hours
Did not achieve full feeds
Table 3 Reasons for interruptions of enteral feeding
High gastric residual volume (GRV)
Difficulty in nasogastric (NG) tube placement
enteral nutrition and more than half of the patients
received less than 90% of protein requirements during the
study period. A study by OLeary-Kelley et al.  also
found that 68% of their mechanically ventilated patients
were underfed. Compared to these studies, our results
indicated a higher number of patients achieving their
caloric requirements. Despite the absence of an Enteral
Nutrition Protocol, the multidisciplinary team of this
tertiary hospital which comprised of an intensivist,
registrars, nurses and dieticians who are responsible for the
mechanically ventilated patients needs may have
contributed to 66% of the patients meeting their nutritional
requirement goal in three days. Further studies are
required to assess if a development of a feeding protocol
would further increase the number of patients achieving
their nutrition target in our population, as have been
proven successful by Mackenzie et al.  Our data
showed a large range in time (0 110 hours) to initiate
feeds for patients admitted into the ICU, with a median
time to start feeds of 15 hours (IQR 659 hours). A
study by Rice et al.  reported that the average time
to initiate enteral feeding after beginning mechanical
ventilation was about two days. According to ESPEN
2006 guideline , feeds should be started within the
first 24 hours of admission to the ICU. However, initiating
enteral feeds within 24 hours of mechanical ventilation
may be difficult as some patients may have other acute
problems that first need to be treated
The time taken to achieve full feeds has its implication
on the overall morbidity of patients in the sense that an
escalating energy deficit has shown to be associated with
increased mortality and morbidity [15,16]. However,
nutrition inadequacy cannot be attributed only to inadequate
delivery but is confounded by the fact that critically ill
patients are frequently in hyper-metabolic and catabolic
states . Simple modifiable factors such as type of feeds,
early enteral feeds , reductions in feed interruptions
 and a feeding protocol  have been postulated to
improve delivery of nutrition and prevent complications
related to underfeeding such as weakness, infections,
increased length of ventilator days and mortality .
Procedures such as planned extubations, tracheotomies
and radiological imaging were the most common reason
that led to feed interruptions in these studies. Similar
findings were reported by others [14,21-24]. Little change or
improvement can be done for this group of patients to
reduce the duration and number of interruptions. Careful
evaluation and implementation of fasting time should
be made on a case by case basis and decisions should
be made based on the type of procedure and surgical
(abdominal, airway or peripheral) or imaging requirements
at the discretion of the ICU consultant.
The next most common reason for feed interruption is
high gastric residual volume (GRV). There was no
significant difference in gastrointestinal intolerance in patients
with GRV greater than 300 ml compared with those less
than 300 ml. No difference in adverse outcomes was
previously reported when GRV was increased to 500 ml .
The majority of feed cessation in this group was for GRV
volume of 200300 ml (51.9%). In recent years, there
appears to be an acceptance of high GRV . The
recommendations were based on the assumption that most
GRV would be aspirated to avoid production of less
favourable outcome. As for this study, no case of
aspiration was reported in all of the 77 patients. Our results are
consistent with other studies that demonstrated
gastrointestinal intolerance as a common reason for interruption
in enteral feeding [5,26,27]. The high percentage of
stoppages even for GRV <200 ml (33.3%) is observed to be
attributed to the lack of feeding protocol in our ICU as well
as the inexperience and lack of knowledge by some
clinicians regarding newer studies on GRV. As this is a
teaching hospital, most of the ad hoc clinical decisions are
made by trainees.
The limitations of this study should be acknowledged.
Our results reflect practices of a single unit in a single
institution. Convenience sampling of subjects receiving
enteral nutrition during a certain period may also not
accurately represent characteristics of a larger sample.
Therefore the results of this study should be interpreted
with caution and should not be generalized to the wider
population of patients on mechanical ventilation
receiving enteral nutrition in Malaysia.
In conclusion, although enteral feeds are started within a
mean time of 22.5 hours and full feeds achieved early,
there is still room for improvement to increase the
number of patients who achieve their caloric requirement
during their stay in the ICU.
ICU: Intensive care unit; GRV: Gastric residual volume; SAPS: Simplified acute
physiology score; ESPEN: The European Society for Clinical Nutrition and
Metabolism; VAP: Ventilator associated pneumonia.
KFY: Design of the study, conduct the study, data analysis and manuscript
drafting. VR: Design of the study, data analysis and manuscript editing. KKW:
Data acquisition and manuscript editing. All authors read and approved the
This study was supported by the University Malaya PPP Grant P0065/2012A
and University Malaya Research Grant (UMRG) RG365/11HTM.
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