Open Journal of Nursing, 2012, 2, 327-331 OJN Published Online November 2012 (
Misconceptions and truths for feeding patients in the
intensive care unit: Case studies with practical nursing
Refaat A. Hegazi*, Mary Ann Cockram, Menghua Luo
Abbott Nutrition, Columbus, USA
Email: *
Received 16 September 2012; revised 22 October 2012; accepted 5 November 2012
The Guidelines for the Provision and Assessment of
Nutrition Support Therapy in the Adult Critically Ill
Patient published in May 2009 (joint guidelines be-
tween the Society of Critical Care Medicine (SCCM)
and the American Society for Parenteral and Enteral
Nutrition (A.S.P.E.N.) have advanced our clinical prac-
tice for the nutritional management of critically ill
patients. In the current article, we will review how to
implement these guidelines using a case study model.
Two mechanically ventilated and tube fed patients
are discussed, one with pneumonia and the second
with severe acute pancreatitis. We address the ques-
tions of the feeding timing, method of administration,
and management of its complications for these two
Keywords: Enteral Nutrition; Critically Ill Patients;
Guidelines; Case Studies
Critical illness is often associated with catabolic stress
and the systemic inflammatory response, which can lead
to complications of increased infectious morbid ity, multi-
organ dysfunction, prolonged hospitalization, and increa-
sed mortality [1]. Critical illness is also associated with
loss of lean body mass, which negatively impacts survi-
val in the intensive care unit (ICU) and post discharge.
The stress response to critical illness can be modulated
nutritionally with the use of early enteral nutrition, ap-
propriate macro- and micronutrient delivery, and ade-
quate glycemic control. A proactive therapeutic strategy
of delivering early nutrition support therapy can help
lessen disease severity, reduce complications, mitigate
inflammation-related catabolism of lean body mass, de-
crease length of stay in the ICU, favorably modulate the
immune response [1,2], and positively impact patient
outcomes. Providing early enteral nutrition within 24 -
48 hours of admission has been shown to reduce hospital
length of stay [3,4], reduce ICU and hospital mortality
[5,6], and reduce infectious complications [3,7].
To help guide clinical practitioners in prescribing and
administering appropriate nutrition al therapy in adult cri-
tically ill patients, the American Society for Parenteral
and Enteral Nutrition (A.S.P.E.N.) and the Society of
Critical Care Medicine (SCCM) published joint guide-
lines in May 2009 [1]. Recommendations of the Guide-
lines are given based on the number and level of evi-
dence available in th e literature. For example, the strong-
est recommendation is a Grad e A recommendation, which
is supported by at least two level I large, randomized
trials. The Grade E recommendation is supported by non-
randomized studies, studies compared with historical con-
trols, case series, uncontro lled studies, or expert opinion.
In the following review we will discuss these guide-
lines and apply them in clinical practice using a case
study model. Through discussing two case studies, the
current article presents common clinical issues that arise
during enteral feeding of the critically ill patients. We
will also review the evidence-supported practice guide-
lines of how to address these issues in order to prevent
unnecessary interruption of enteral feeding. The experi-
ence and learning from these two cases could serve as a
clinical tool to be generally used when enterally feeding
the critically ill patients.
A 55-year-old male presents to the emergency depart-
ment with shortness of breath, productive cough of thick
green sputum, wheezing and general malaise for the past
3 days. His vital signs are: Blood pressure 122/70, Heart
rate 100, Temperatur e 100.4˚F, Respiratory rate 24.
The patient is admitted to the hospital and sputum is
sent for culture and sensitivity. Chest X-ray indicates
right lower lobe pneumonia. The patient is admitted to
*Corresponding a uthor.
R. A. Hegazi et al. / Open Journal of Nursing 2 (2012) 327-331
the medical unit for monitoring and treatment of pneu-
Twelve hours after admission the patient’s respiratory
status further declines and he is transferred to the ICU.
The patient has hypoxemia, leukocytosis, and respiratory
acidosis (Table 1). He is mechanically ventilated and
vasopressors and propofol were started at this time.
2.1. How Soon after Admission to the Hospital
Should Feeding Be Started?
We can look to the literature and guidelines to answer
this question. In a study by Artinian and colleagues in
2006 [6] they retrospectively analyzed prospectively
collected ICU database where they looked at the associa-
tion of early enteral feeding and outcome in critically ill
mechanically-ventilated patients. This was a large study
that included more than 4000 patients. Based on when
they received enteral nutrition relative to mechanical
ventilation onset, patients were classified into 2 groups:
early feeding (within 48 hours) (n = 2537) or the late
feeding (n = 1512). The primary outcome of this study
was both ICU and hospital mortality. Results show that
patients who were fed within 48 hours of mechanical
ventilation had less ICU and hospital mortality than the
late feeding group (18.1% vs 21.4%, P = 0.01; 28.7% vs
33.5%, P = 0.001, respectively). This suggests that early
feeding (within 48 hours) is associated with lower mor-
tality. This early feeding is endorsed by the A.S.P.E.N.
and SCCM guidelines advocating that enteral feeding
should be started early within 24 - 48 hours of admission
For our case study patient, the recommendation is to
start enteral nutrition within the first 24 - 48 hours of
admission assuming that the gastrointestinal (GI) tract is
functioning. This question of functioning GI tract should
be addressed early on when we see or care for ICU pa-
tients. The presence of bowel sounds is not the so le indi-
cation for starting tube feeding. Assessing GI function
should also include medical history and physical exami-
nation findings.
2.2. Why Should We Start Feeding Early?
Studies have shown that early initiation of enteral feed-
ing is associated with decreased infectious complications,
shorter length of stay in the ICU, and some evidence of
Table 1. Admitting laboratory results of Case 1 patient.
WBC (×106/mL) Hgb (g/dL) Hct (%) pH
14,000 11.5 42 7.31
PaO2 (mmHg) SaO2 (%) PaCO2 (m mHg) HCO3 (mmol/L)
64 76 56 24
reduced mortality, as co mpared to late feeding [1].
2.3. Why Should We Feed Enterally?
To answer this question, we can review the A.S.P.E.N./
SCCM guidelines for feeding critically ill patients [1]. In
patients with a functioning GI tract (e.g., patients with
severe acute pancreatitis) the recommendation is that
enteral nutrition (EN) is the preferred route of feeding
over parenteral nutrition (PN). Of note, there are, how-
ever, some patients who have a non-functioning GI tract
who will require nutrition support therapy with PN.
A meta-analysis included in the Canadian clinical prac-
tice guidelines looked at studies that compared EN ver-
sus PN on infectious complications in critically ill pa-
tients [8]. The pooled effect of these studies is that EN
significantly reduces the risk of infection and length of
stay in ICU patients. The cost associated with EN is
much less than that of PN with an estimated reduction of
approximately $4000 dollars per patient [9].
For our case study patient, the recommendation, there-
fore, is to start enteral feeding because it is associated
with less infectious complications and improved clinical
outcomes. Physiologically, enteral feeding preserves gut
function because it is essential for the optimum func-
tioning of the gut associated lymphoid tissue, a major
immune system in our body that depends on a trophic ef-
fect of nutrients. Immune function is supported by ente-
ral feeding.
2.4. Should We Start Feeding at Goal Rate or
Start at a Lower Rate?
The recommendation is to start at a low rate (e.g., 20 - 30
mL/hr) and assess for GI tolerance allowing for gut ac-
climatization of the intestinal mucosa to the enteral feed-
ing. This rate of enteral feeding is used for a reasonable
period of time; (e.g., 8 - 12 hours) however, sometimes
this range is more if the patient is hemodynamically un-
stable and we want to start with trophic feeding for a
while, before advancing the feeding to goal rate. The
decision to advance to goal rate depends on patient tol-
erance and the hemodynamic condition of the patient.
2.5. This Patient Is on Vasopressors; Can We
Still Feed This Patient Enterally?
Each patient should be assessed individually, asking how
severe is the hemodynamic instability, how many vaso-
pressors and what doses is the patient on and whether
these doses are escalating. In general, trophic feeding in
this clinical setting will not be an absolute contraindica-
tion as long the patient’s clinical and nutritional condi-
tions are closely monitored by the clinical team (e.g.,
hemodynamic status, GI tolerance, and functional effects
of trophic feeding) to best decide whether trophic feed-
Copyright © 2012 SciRes. OPEN ACCESS
R. A. Hegazi et al. / Open Journal of Nursing 2 (2012) 327-331 329
ing should be advanced to goal depending on the pa-
tient’s condition. In a 2010 study, Khalid and colleagues
[5] retrospectively reviewed the association of ICU and
hospital mortality with early enteral feeding (within 48
hours) in patients who were on vasopressors (by defini-
tion, these patients were hemodynamically unstable).
They found that early EN was associated with lower ICU
and hospital mortality as compared with late EN (22.5%
vs 28.3%, P = 0.03; 33.8% vs 43.9%, P < 0.001, respec-
In summary, the learning points from this patient case
Early enteral feeding of critically ill patients is recom-
mended based on the A.S.P.E.N./SCCM evidence-
based guidel i nes [1].
Enteral feeding is associated with more favorable
outcomes compared to parenteral feeding.
Assessing patients’ GI function and tolerance to en-
teral formulations helps patients meet nutritional re-
quirements and minimize any GI complications asso-
ciated with starting enteral feeding.
A 58-year-old obese (BMI 36) female presents to the
emergency department complaining of 3 days of severe
abdominal pain which radiates to the back, with nausea
and vomiting. Her vital signs are: Blood pressure 88/48;
Heart rate 132; Temperature 102.0˚F; Respiratory rate 34.
See Table 2 for laboratory values.
Pancreatic enzymes are elevated and the CT of the
abdomen reveals there is a large pseudocyst that is com-
pressing the gastric outlet causing obstruction and peri-
pancreatic edema. She is identified as having severe
acute pancreatitis. The triglycerides are elevated; there is
some evidence of kidney dysfunction, and mild elevation
of liver enzymes.
By reviewing white blood cell (WBC) count, vital
signs, and the diagnosis of severe acute pancreatitis, we
can identify that the patient has systemic inflammatory
response syndrome. With her progressive course of hy-
poxemia, the patient is started on mechanical ventilation.
Table 2. Admitting laboratory results of Case 2 patient.
(×106/mL) Hct (%) Glucose
(mg/dL) BUN (mg/dL)
14,000 45 240 52
(mg/dL) Amylase
(IU/L) Lipase (IU/L) AST (IU/L)
2.1 590 1400 67
ALT (IU/L) Bilirubin
(mg/dL) INR Triglycerides
55 1.1 1.2 380
3.1. This Patient Is Obese; Can She Tolerate
Being Kept NPO?
To an swer this question, we need to look at the new defi-
nition of malnutrition integrating the inflammatory proc-
ess in the diagnosis of malnutrition. According to Jensen
et al. [10] one needs to assess nutrition risk, does the
patient have low food intake or loss of lean body mass.
Next, we need to evaluate whether inflammation is pre-
sent. If inflammation is present, is it mild-moderate or
severe. Patients with chronic disease, such as chronic
kidney disease, cancer, rheumatoid arthritis, or sarco-
penic obesity, by definition are malnourished with mild
to moderate inflammation. If inflammation is severe as
encountered in sepsis, burns, and trauma it is diagnosed
as acute disease-related malnutrition.
The patient in the case study is malnourished, because
she has manifestation of systemic inflammatory response
syndrome and meets the diagnostic criteria of acute se-
vere inflammation-associated malnutrition.
The answer to the question then is no, she should not
be kept NPO. Obese patients are not over-nourished or
even well-nourished. Sarcopenic obesity (loss of muscle
mass or strength) commonly seen in critically ill obese
patients complicates the critical illness. Weight loss at
this time should not be a goal for this ICU patient. We
need to distinguish between the obese individual with
preserved muscle mass and the critically ill obese person
who needs to be fed in order to preserve lean body mass
as well as to nutritionally stimulate gut associated lym-
phoid tissue.
3.2. Can Patients with Severe Acute Pancreatitis
Be Fed Enterally or Is Parenteral Nutrition
(PN) the Best Choice for Feeding Patients
with This Condition?
In a meta-analysis published in 2004 by Marik and Za-
loga [11], randomized controlled trials in patients with
severe acute pancreatitis being fed EN or PN were ana-
lyzed to evaluate the effect of the type of feeding on in-
fectious complications. Enteral nutrition in patients with
severe acute pancreatitis was associated with lower inci-
dence of infections, less surgical interventions, and length
of hospital stay. Clearly, EN has benefits beyond calories
and protein and plays a role in maintaining a physiologi-
cal homeostatic function of the gut associated lymphoid
The recommendation for this patient is th at EN is pre-
ferred over PN as a safe source of feeding that can de-
crease risk of infectious and surgical interventions and
length of ICU stay. The decision to start PN will depend
on the GI function of the patient and the adequacy of
nutritional therapy by EN to meet the patient’s increased
nutritional needs.
Copyright © 2012 SciRes. OPEN ACCESS
R. A. Hegazi et al. / Open Journal of Nursing 2 (2012) 327-331
3.3. When Should Enteral Feeding Be Started for
This Patient?
To answer this question, we can review a retrospective
analysis of patients with severe acute pancreatitis who
were treated according to an established protocol [12].
All patients were started on tube feed ing within 24 hours
of getting a consult with the same nasogastric-jejunal
tube, and all patients were fed a peptide-based formula.
In this analysis, we looked at the outcome of ICU length
of stay and its association with the time from initiating
tube feeding to the time to reach goal rate feeding. We
found that patients who reached goal rate feeding in 3 or
less days from the time of initiating feeding had shorter
length of ICU stay as compared to patients who never
reached goal rate of feeding. When we looked at APA-
CHE II scores to see if the severity of illness was differ-
ent between those patients who reached goal feeding in 3
days or less compared to those who never reached goal
rate, no difference was found between the groups in se-
verity of illness based on APACHE II scores. This sug-
gests that the timing between initiating enteral feeding
and reaching goal feeding is associated with better out-
comes irrespective of the severity of disease. We also
looked at the time from the onset of pain to the time to
reach goal feeding rate. The patients who reached goal
rate from the onset of pain earlier spent less time in the
ICU. In conclusion the earlier we feed (within 24 hours)
and the earlier we reach goal rate appears to be associ-
ated with better outcomes. Achievement of distal jejunal
feeding goals early was associated with shorter ICU
length of stay irrespective of severity of acute pancreati-
The recommendation is that enteral feeding should be
started as early as the first 24 - 48 hours, assuming a
functioning GI tract as early initiation of enteral feeding
is associated with favorable clinical outcomes.
With our patient, a nasal jejunal tube was not able to
be placed beyond the ligament of Treitz so a nasogastric
tube was inserted at the bedside. A continuous feeding is
started at 85 mL/hour via a feeding pump. The patient
develops diarrhea and has a total of 6 loose stools over
the next 24 hours. Gastric residual volumes (GRV) are
being checked every 4 hours and are running between
250 and 300 mL at each 4-hour check.
3.4. What Is Likely Contributing to the Diarrhea
This Patient Is Experiencing? What Should
We Do to Manage the Diarrhea?
In a review of the relationship between tube-feeding ini-
tiation and diarrhea, studies have found that in up to 60%
of the cases of tube-feeding associated diarrhea, the
cause was not the tube feeding itself, it was other causes
[13]. The two major causes were medications (e.g., sor-
bitol-contain ing, antibiotics, proton pump inhibito rs) and
intestinal infections [14]. Before stopping the tube feed-
ing, one should exclude other causes of diarrhea other
than the enteral feeding and then to slow the rate and
maintain for more than 12 hours, even maybe 24 hours,
if necessary, to allow for gut acclimatization and then
after enough period of time, slowly advance the rate. If
the patient still does not tolerate the lower rate, we
should consider changing the formula from a standard,
intact protein formula, to a hydrolyzed, peptide-based
formula that can help with improving the GI toleran ce. If
the patient is not responding to this change in formula
type to a peptide-based formula, in some cases, the only
solution is to switch the patient from enteral feeding to
parenteral feeding.
3.5. How Would You Manage a Patient Who Is
Having GRV between 250 - 300 mL Every 4
The A.S.P.E.N./SCCM guidelines [1] recommend a GRV
up to 500 mL without switching formulas or stopping the
feeding. The guidelines advocate the use of promotility
agents to help with gastric motility. The studies relating
increased GRV and aspiration pneumonia are not consis-
tently strong. Aspiration precautions should always be
implemented, such as raising the head of the bed 30˚ -
45˚, and if there is a high risk of aspiration, use a duode-
nal or postpyloric feeding instead of gastric feeding. By
using aspiration precautions one should not have to
worry about GRV, if a promotility agent is used and the
patient is monitored.
To summarize points discussed with this patient case:
Early enteral feeding is recommended for ICU pa-
tients as well as patients with severe acute pancreati-
tis according to the A.S.P.E.N./SCCM guidelines [1].
Diarrhea in tube fed patients is most often caused by
factors other than the tube feeding (exclude other
factors, adjust tube feeding rates before stopping the
feeding or switching for mula types).
GRV is an important factor to monitor. A value of
GRV up to 500 mL may be acceptable according to
the A.S.P.E.N./SCCM guidelines [1]. Use of proki-
netic agents can help with gastric emptying. Aspira-
tion precautions should be used in all ICU patients.
In summary, the integration of the evidence-based
practice guidelines in the nutritional management of cli-
nical issues commonly faced when enterally feeding pa-
tients in the ICU could help improve clinical outcomes
by optimizing the nutritional status of the patients via
preventin g unnecessary stopp ing of tub e feeding . Unwar-
ranted interruption of enteral feeding should be discou-
raged and every effort should be made to maintain and
improve the nutritional status of critically ill patients for
Copyright © 2012 SciRes. OPEN ACCESS
R. A. Hegazi et al. / Open Journal of Nursing 2 (2012) 327-331
Copyright © 2012 SciRes.
[7] Heyland, D.K., Dhaliwal, R., Drover, J.W., Gramlich, L.
and Dodek, P. (2003) Canadian clinical practice guide-
lines for nutrition support in mechanically ventilated,
critically ill adult patients. Journal of Parenteral and En-
teral Nutrition, 27, 355-373.
better clinical outcome.
R.A. Hegazi, M.A. Cockram and M. Luo are full time employees of
Abbott Laboratories. The material presented in this article is based on
the best-known clinical evidence and is not affected by this financial
[8] 2009 Clinical Practice Guidelines. The Use of EN vs PN,
8 October 2012.
REFERENCES [9] Cangelosi, M.J., Auerbach, H.R. and Cohen, J.T. (2011)
A clinical and economic evaluation of enteral nutrition.
Current Medical Research and Opinion, 27, 413-422.
[1] McClave, S.A., Martindale, R.G., Vanek, V.W., McCar-
thy, M., Roberts, P., Taylor, B., Ochoa, J.B., Napolitano,
L. and Cresci, G. (2009) Guidelines for the provision and
assessment of nutrition support therapy in the adult criti-
cally ill patient: Society of Critical Care Medicine (SCCM)
and American Society for Parenteral and Enteral Nutrition
(A.S.P.E.N.). Journal of Parenteral and Enteral Nutrition,
33, 277-316. doi:10.1177/0148607109335234
[10] Jensen, G.L., Mirtallo, J., Compher, C., Dhaliwal, R., For-
bes, A., Grijalba, R.F., Hardy, G., Kondrup, J., Labada-
rios, D., Nyulasi, I., Castillo Pineda, J.C. and Waitzberg,
D. (2010) Adult starvation and disease-related malnutri-
tion: A proposal for etiology-based diagnosis in the cli-
nical practice setting from the International Consensus
Guideline Committee. Journal of Parenteral and Enteral
Nutrition, 34, 156-159. doi:10.1177/0148607110361910
[2] Wischmeyer, P.E. and Heyland, D.K. (2010) The future
of critical care nutrition therapy. Critical Care Clinics, 26,
433-441. doi:10.1016/j.ccc.2010.04.011 [11] Marik, P.E. and Zaloga, G.P. (2004) Meta-analysis of pa-
renteral nutrition versus enteral nutrition in patients with
acute pancreatitis. British Medical Journal, 328, 1407.
[3] Kattelmann, K.K., Hise, M., Russell, M., Charney, P.,
Stokes, M. and Compher, C. (2006) Preliminary evidence
for a medical nutrition therapy protocol: Enteral feedings
for critically ill patients. Journal of the American Dietetic
Association, 106, 1226-1241.
[12] Hegazi, R., Raina, A., Graham, T., Rolniak, S., Centa, P.,
Kandil, H. and O’Keefe, S.J. (2011) Early jejunal feeding
initiation and clinical outcomes in patients with severe
acute pancreatitis. Journal of Parenteral and Enteral Nu-
trition, 35, 91-96. doi:10.1177/0148607110376196
[4] Andersen, H.K., Lewis, S.J. and Thomas, S. (2006) Early
enteral nutrition within 24h of colorectal surgery versus
later commencement of feeding for postoperative com-
plications. Cochrane Database of Systematic Reviews,
[13] Edes, T.E., Walk, B.E. and Austin, J.L. (1990) Diarrhea
in tube-fed patients: Feeding formula not necessarily the
cause. The American Journal of Medicine, 88, 91-93.
[5] Khalid, I., Doshi, P. and DiGiovine, B. (2010) Early en-
teral nutrition and outcomes of critically ill patients treat-
ed with vasopressors and mechanical ventilation. Ameri-
can Journal of Critical Care, 19, 261-268.
[14] Btaiche, I.F., Chan, L.N., Pleva, M. and Kraft, M.D. (2010)
Critical illness, gastrointestinal complications, and medi-
cation therapy during enteral feeding in critically ill adult
patients. Nutrition in Clinical Practice, 25, 32-49.
[6] Artinian, V., Krayem, H. and DiGiovine, B. (2006) Ef-
fects of early enteral feeding on the outcome of critically
ill mechanically ventilated medical patients. Chest, 129,
960-967. doi:10.1378/chest.129.4.960