Misconceptions and truths for feeding patients in the intensive care unit: Case studies with practical nursing solutions

doi:10.4236/ojn.2012.223047

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Open Journal of Nursing, 2012, 2, 327-331 OJN

http://dx.doi.org/10.4236/ojn.2012.223047 Published Online November 2012 (http://www.SciRP.org/journal/ojn/)

Misconceptions and truths for feeding patients in the

intensive care unit: Case studies with practical nursing

solutions

Refaat A. Hegazi*, Mary Ann Cockram, Menghua Luo

Abbott Nutrition, Columbus, USA

Email: *[email protected]

Received 16 September 2012; revised 22 October 2012; accepted 5 November 2012

ABSTRACT

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

patients.

Keywords: Enteral Nutrition; Critically Ill Patients;

Guidelines; Case Studies

1. INTRODUCTION

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.

2. PATIENT CASE 1

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.

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R. A. Hegazi et al. / Open Journal of Nursing 2 (2012) 327-331

328

the medical unit for monitoring and treatment of pneu-

monia.

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

[1].

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-

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-

tively).

In summary, the learning points from this patient case

are:

 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.

3. PATIENT CASE 2

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.

WBC

(×106/mL) Hct (%) Glucose

(mg/dL) BUN (mg/dL)

14,000 45 240 52

Creatinine

(mg/dL) Amylase

(IU/L) Lipase (IU/L) AST (IU/L)

2.1 590 1400 67

ALT (IU/L) Bilirubin

(mg/dL) INR Triglycerides

(mg/dL)

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

tissue.

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.

R. A. Hegazi et al. / Open Journal of Nursing 2 (2012) 327-331

330

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-

tis.

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

Hours?

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

R. A. Hegazi et al. / Open Journal of Nursing 2 (2012) 327-331

331

[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.

doi:10.1177/0148607103027005355

better clinical outcome.

4. ACKNOWLEDGEMENTS

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

relationship.

[8] 2009 Clinical Practice Guidelines. The Use of EN vs PN,

8 October 2012.

http://www.criticalcarenutrition.com/docs/cpg/1.0envspn

_07_FINAL.pdf.

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