Summary: In 2003 an audit was carried out on an ICU which demonstrated that the incidence of constipation was high and that this could contribute to the failure to wean patients from mechanical ventilation (Mostafa et al, 2003). A protocol was introduced to standardise the assessment and management of constipation. This article explores why patients in intensive care are at risk of constipation and presents the results of a second audit, carried out after the protocol was introduced, to assess its impact on patients.

Authors: Gillian Ritchie, MRes, BA, RGN, is senior nurse research
and development Royal Liverpool University Hospital Trust; Lorraine Burgess, MSc, PGCE, RGN, is senior lecturer advanced practice, Liverpool John Moores University; Sobhy Mostafa, MD, FRCA, MBChB, MRCS, LRCP, is retired consultant in anaesthesia and intensive care medicine, Royal Liverpool University Hospital Trust; Richard Wenstone, MBChB, FRCA, is consultant in intensive care. Royal Liverpool University Hospital Trust.

Management of constipation can be overlooked in the technology-rich intensive care environment. Nurses in ICU have to carry out complex activities including supporting major organs, administering inotropes, checking and replacing electrolytes and setting up renal dialysis. As a consequence bowel care, a basic bodily function, may be overlooked.

Constipation can cause symptoms of abdominal discomfort and cramps, feeling of bloatedness, nausea, and loss of appetite (Clinical Knowledge Summaries, 2008). It can have serious implications such as chronic faecal loading or impaction that can lead to faecal incontinence, urinary tract infection, rectal bleeding and even rectal prolapse (Clinical Knowledge Summaries, 2008).

Kollefand Neelon-Kollef (1991) reported that constipation has proved fatal in some patients with deep venous thrombosis. Straining to pass a stool has produced pressure that can embolise a thrombosis leading to pulmonary embolism.

While treatment for constipation is usually very effective, it has been reported that in some cases it can take several months before a regular bowel pattern is re-established (Clinical Knowledge Summaries, 2008).

Constipation may also allow overgrowth of bacteria in the digestive tract. Bacterial overgrowth is a major cause of nosocomial infection and sepsis, which can prolong a stay in ICU (Asai, 2007).

Why are patients in ICU at risk?

There are psychological and physiological factors increasing the chance of constipation in patients in ICU. Constipation usually results from multiple interacting causative factors such as:

  • Decreased gastrointestinal motility, which may be associated with sepsis. Many patients in ICU have sepsis/shock which impairs gastrointestinal motility through elevated levels of circulating endotoxins, inflammatory mediators, and enhanced inducible nitric oxide production (van der Spoel et al, 2007);
  • Immobility due to illness, injury or sedation;
  • Stool quality, which may be affected by lack of fluid and fibre;
  • Lack of access to appropriate toilet facilities;
  • Unconscious patients may not feel the need to defecate and cannot express this need.

It is difficult to provide privacy for conscious patients in ICU if they need to defecate. Patients are often attached to monitors and multiple infusions, making it impossible to move them from the bedside area to the toilet. It can be embarrassing to try and use a bedpan in a noisy unit when curtains are the only barrier between the individual and other patients, nurses, doctors and visitors.

Using a bedpan increases the likelihood of constipation (Clinical Knowledge Summaries, 2008). Intra-abdominal pressure needs to be raised for successful defecation and this is impaired while lying on a bedpan. Bed rest or a period of immobility is thought to result in a weakening of the abdominal wall muscles leading to difficulty in raising the intra-abdominal pressure sufficiently for defecation to occur (Kyle, 2007). Ignoring the urge to defecate can significantly increase the risk of constipation (World Gastroenterology Organisation, 2007; Clinical Knowledge Summaries, 2008).

There are recommendations for the assessment and management of constipation but it is difficult to transfer this to the intensive care environment.

The Registered Nurses Association of Ontario (RNAO) (2005) made recommendations and guidelines for the assessment of those at risk of constipation that include accessing the patient’s history and previous bowel habits. In ICU many patients are unconscious and therefore unable to provide their own history. When a history is obtained from a next of kin, information about bowel habits may not be easy to obtain.

Norgine risk assessment tool


  • Medical condition
  • Medication (more than five drugs
  • Toileting facilities
  • Mobility
  • Nutritional intake
  • Fluid intake

Source: Kyle (2007)

The Norgine risk assessment tool predicts a patient’s risk of constipation and encourages nurses to adopt a proactive approach with a focus on prevention. It was developed using the evidence from a systematic review of the literature on constipation (Kyle, 2007). As the tool is new, no data currently exists on its validity or reliability, however, it is an excellent reminder to nurses to assess patients’ bowel care requirements.

The Norgine tool identifies six risk factors associated with the development of constipation. These are listed in Box 1.

If the Norgine tool was used in an ICU environment, all patients would undoubtedly be classed as ‘high risk’ of constipation.
Certain medical conditions predispose a patient to the risk of constipation either because of altered bowel pathophysiology due to their medical condition or the impact the medical condition has on a patient’s health in general, such as reduced mobility or frailty (Kyle, 2007). Intensive care patients are severely ill and mobility is reduced with the majority of patients being confined to bed.

Polypharmacy as a risk factor applies to patients in ICU. Multiple organ dysfunction and multiple organ failure is generally treated with numerous pharmacological interventions (Barkin, 2003). It is important to review medications patients are receiving as many, including opiates, diuretics and antihypertensives, impair colon motility (Clinical Knowledge Summaries, 2008; World Gastroenterology Organisation, 2007).

Nutritional and fluid intake is often impaired due to reduced gut motility. Many patients receive feed enterally via a naso-gastric tube or intravenously via total or partial parental nutrition. Some patients will be dehydrated or have fluid restrictions due to their critical condition.

Initial audits

In 2002 an audit was conducted in a 13-bed general, mixed, adult ICU in an inner-city teaching hospital to identify the number of patients with constipation. Patients include those with surgical, medical, trauma and renal problems.

Hill et al (1998) and Evans (1996) had both defined constipation as failure of the bowel to move for more than three consecutive days; the same definition was therefore adopted for this audit.

As the definition of constipation was greater than three days, all ventilated patients admitted to ICU for three days or more were included. Patients who had recent bowel surgery and those with a length of stay of three days or less were excluded. Data was prospectively collected over a three-month period. Data collected is listed in Box 2.


  • Age, sex and length of stay
  • APACHE II score (a severity of disease classification system)
  • Diagnosis and the incidence and duration of constipation
  • Volume of gastric aspirates, as gastric aspirate can increase in response sepsis and shock which slow gut motility
  • Ability to enterally feed or wean patients from mechanical ventilation
  • Bowel care such as use of laxatives

Results showed that constipation occurred in a high percentage of patients. Forty-eight patients were included in the study; constipation occurred in 83% (40). More of the constipated patients 42.5% (17), failed to wean from mechanical ventilation than nonconstipated patients (0%) (Mostafa et al, 2003).

The results suggested an urgent need for a bowel care protocol and this was subsequently developed and implemented. Prior to the introduction of the protocol, there were no guidelines for prescribing laxatives. Patient management was dependent on a nurse identifying a problem, highlighting it and the clinician on duty deciding how it should be treated.

Teaching sessions were carried out in the unit and the results of the audit were reported to staff. Education sessions highlighted the complications associated with constipation and reinforced the need for improved documentation of bowel movements and the implementation of the protocol.

The daily management charts, which are completed by nurses and include vital signs and ventilation observations, were adapted to include documentation of bowel care. A box was included so that nurses could add in if the patient had their bowels opened and also the ‘number of days’ since a bowel action so that the nurse could easily identify if their patient was at risk of constipation.

When the patient reached day three, the nurse would then identify that the patient was at risk of constipation, an assessment would be carried out and laxatives prescribed following the protocol.

Following the introduction of the protocol and education, a follow-up audit took place approximately 12 months later. The inclusion and exclusion criteria were identical to the initial audit.

Over a three-month period 42 patients met the inclusion criteria. Constipation occurred in 40% (17). Of those who suffered with constipation, 24% (4) failed to wean from ventilation compared with only three out of 25 (12%) non-constipated patients.

Results revealed that the introduction of the protocol was associated with a reduction in the incidence of constipation from 83% to 40%.


In both audits some patients experienced constipation on more than one occasion. However, the number of days patients were constipated was reduced following introduction of the protocol. Before using the protocol nearly 50% of patients were constipated for six days or more. Following the implementation of the protocol 50% of patients had a bowel movement by day four.

It is unlikely that the high incidence of constipation is unique to our ICU. Dorman et al (2004) expressed concern that within the technologically intense environment of the modern ICU, bowel care has often been overlooked and is sometimes focused on as an ‘afterthought’. Studies looking at medical records to assess the documentation of bowel assessment and defecation showed that the use of a bowel management protocol improved documentation of the assessment of bowel function (Dorman et al, 2004; McKenna et al, 2001).

There is no clear evidence regarding which laxative is most effective in treating constipation (World Gastroenterology Organisation, 2007). A double-blind, placebo-controlled study found that both lactulose and polyethylene glycol are more effective in promoting defecation than placebo in two tertiary ICUs (van der Spoel et al, 2007). For all groups, defecation within six days after admission was associated with a shorter length of stay in ICU (van der Spoel et al, 2007).

This audit used a previously published definition of constipation; ‘failure of the bowel to move for more than three consecutive days’(Hill et al, 1998). However, a more recent literature search found different views about what constitutes a diagnosis of constipation. Terms such as difficult, dry, hard, abnormally large or abnormally small stools are used. Some adults normally pass stools more than once per day (Clinical Knowledge Summaries, 2008) and their definition of constipation may be very different from Hill et al (1998).

The definition of three days may be underestimating constipation in the ICU; however, in the absence of a bowel history it may be necessary to adopt some form of standardisation. In the absence of this history each patient should be assessed individually and include assessment of bowel sounds and bowel palpitation as bowel care may need to be commenced prior to the three days.

Nurses admitting patients to hospital should always collect a bowel history and record bowel function as this can assist in their management should they require critical or intensive care.

The major limitation of this audit is that it consisted of a small sample size and was carried out in one unit.


The audit has demonstrated that the introduction of a bowel protocol was associated with a reduction in the incidence of constipation from 83% to 40%. This audit also confirmed previous findings that more constipated patients fail to wean from mechanical ventilation than non-constipated patents.

Multiple factors could explain failure to wean from ventilation therefore further research is warranted in this area but if constipation does cause failure to wean from mechanical ventilation this may lead to increases in length of stay in ICU.