Intestinal motility disturbances in intensive care patients pathogenesis and clinical impact

[Intraabdominal hypertension and abdominal compartment syndrome]

Although intraabdominal pressure (IAP) has been studied for more than 100 years, the concepts of intraabdominal hypertension (IAH) and abdominal compartmental syndrome (ACS) have only been developed as clinical entities of interest in intensive care in the last 5 years. At the first Congress on Abdominal Compartment Syndrome in December 2004, a series of definitions were established, which were published in 2006. IAH is defined as IAP ≥ 12 mmHg and is classified in four severity grades, the maximum grade being ACS, with the development of multiorgan failure. The incidence of IAH in patients in intensive care units is high, around 30% at admission and 64% in those with a length of stay of 7 days. The increase in IAP leads to reduced vascular flow to the splenic organs, increased intrathoracic pressure and decreased venous return, with a substantial reduction in cardiac output. If IAH persists, these physiopathologic episodes are followed by the development of multiorgan failure with renal, cardiocirculatory and respiratory failure and intestinal ischemia. Mortality from untreated ACS is higher than 60%. The only treatment for ACS is surgical decompression. In patients with moderate IAH, medical treatment should be optimized, based on the following measures: a) serial IAP monitoring; b) optimization of systemic perfusion and the function of the distinct systems in patients with high IAP; c) instauration of specific measures to decrease IAP; and d) early surgical decompression for refractory IAH. The application of the medical measures that can reduce IAP and early abdominal decompression in ACS improve survival in critically ill patients with IAH.

Drug-induced acute liver failure and gastrointestinal complications

The objective of this article is to describe adverse drug events related to the liver and gastrointestinal tract in critically ill patients. PubMed and other resources were used to identify information related to drug-induced acute liver failure, gastrointestinal hypomotility, constipation, diarrhea, gastrointestinal bleeding, and pancreatitis in critically ill patients. This information was reviewed, and data regarding pathophysiology, common drug causes, and guidelines for prevention and management were collected and summarized. In cases in which data in critically ill patients were unavailable, data were extrapolated from other patient populations. Drug-induced acute liver failure can be caused by many drugs routinely used in the intensive care unit and may be associated with significant morbidity and mortality. Drug-related hypomotility and constipation and drug-related diarrhea are reported with many drugs, and these are common adverse drug events in critically ill patients that can substantially complicate the care of these patients. Drug-induced gastrointestinal bleeding and drug-induced pancreatitis occur less frequently, can range in disease severity, and can be associated with morbidity and mortality. Many drugs used in critically ill patients are associated with adverse drug events related to the liver and gastrointestinal tract. Critical care clinicians should be aware of common drug causes of drug-induced acute liver failure, gastrointestinal hypomotility, constipation, diarrhea, gastrointestinal bleeding, and pancreatitis, and should be familiar with the prevention and management of these diverse conditions.

Critical illness, gastrointestinal complications, and medication therapy during enteral feeding in critically ill adult patients

Critically ill patients who are subjected to high stress or with severe injury can rapidly break down their body protein and energy stores. Unless adequate nutrition is provided, malnutrition and protein wasting may occur, which can negatively affect patient outcome. Enteral nutrition (EN) is the mainstay of nutrition support therapy in patients with a functional gastrointestinal (GI) tract who cannot take adequate oral nutrition. EN in critically ill patients provides the benefits of maintaining gut functionality, integrity, and immunity as well as decreasing infectious complications. However, the ability to provide timely and adequate EN to critically ill patients is often hindered by GI motility disorders and complications associated with EN. This paper reviews the GI complications and intolerances associated with EN in critically ill patients and provides recommendations for their prevention and treatment. It also addresses the role of commonly used medications in the intensive care unit and their impact on GI motility and EN delivery.

Intensive Care Unit-acquired infection as a side effect of sedation

Introduction

Sedative and analgesic medications are routinely used in mechanically ventilated patients. The aim of this review is to discus epidemiologic data that suggest a relationship between infection and sedation, to review available data for the potential causes and pathophysiology of this relationship, and to identify potential preventive measures.

Methods

Data for this review were identified through searches of PubMed, and from bibliographies of relevant articles.

Results

Several epidemiologic studies suggested a link between sedation and ICU-acquired infection. Prolongation of exposure to risk factors for infection, microaspiration, gastrointestinal motility disturbances, microcirculatory effects are main mechanisms by which sedation may favour infection in critically ill patients. Furthermore, experimental evidence coming from studies both in humans and animals suggest that sedatives and analgesics present immunomodulatory properties that might alter the immunologic response to exogenous stimuli. Clinical studies comparing different sedative agents do not provide evidence to recommend the use of a particular agent to reduce ICU-acquired infection rate. However, sedation strategies aiming to reduce the duration of mechanical ventilation, such as daily interruption of sedatives or nursing-implementing sedation protocol, should be promoted. In addition, the use of short acting opioids, propofol, and dexmedetomidine is associated with shorter duration of mechanical ventilation and ICU stay, and might be helpful in reducing ICU-acquired infection rates.

Conclusions

Prolongation of exposure to risk factors for infection, microaspiration, gastrointestinal motility disturbances, microcirculatory effects, and immunomodulatory effects are main mechanisms by which sedation may favour infection in critically ill patients. Future studies should compare the effect of different sedative agents, and the impact of progressive opioid discontinuation compared with abrupt discontinuation on ICU-acquired infection rates.

Disparate response to metoclopramide therapy for gastric feeding intolerance in trauma patients with and without traumatic brain injury

Patients with traumatic brain injury (TBI) have delayed gastric emptying and often require prokinetic drug therapy to improve enteral feeding tolerance. The authors hypothesized that metoclopramide was less efficacious for improving gastric feeding tolerance for trauma patients with TBI compared to trauma patients without TBI. A retrospective analysis was conducted of patients admitted to the trauma or neurosurgical intensive care unit who received gastric feeding from January 2006 to April 2008. Gastric feeding intolerance was defined by a gastric residual volume >200 mL or emesis with abdominal distension or discomfort. Patients with gastric feeding intolerance were given metoclopramide 10 mg intravenously every 6 hours, followed by a dose escalation to 20 mg, and then combination therapy with metoclopramide and erythromycin 250 mg intravenously every 6 hours if intolerance persisted. In total, 882 trauma patients (49% with TBI) were evaluated. TBI patients had a higher incidence of gastric feeding intolerance than those without TBI (18.6% vs 10.4%, P < or = .001). Efficacy rates for metoclopramide 10 mg, metoclopramide 20 mg, and metoclopramide-erythromycin were 55%, 62%, and 79%, respectively (P < or = .03). Metoclopramide failure occurred in 54% of patients with TBI compared to 35% of patients without TBI, respectively (P < or = .02), due to a greater prevalence of tachyphylaxis. Single-drug therapy with metoclopramide was less effective for TBI trauma patients compared to trauma patients without TBI. Combination therapy with erythromycin as first-line therapy for TBI trauma patients with gastric feeding intolerance is indicated if there are no contraindications or significant drug interactions.

A randomised controlled comparison of early post-pyloric versus early gastric feeding to meet nutritional targets in ventilated intensive care patients

Introduction

To compare outcomes from early post-pyloric to gastric feeding in ventilated, critically ill patients in a medical intensive care unit (ICU).

Methods

Prospective randomized study. Ventilated patients were randomly assigned to receive enteral feed via a nasogastric or a post-pyloric tube. Post-pyloric tubes were inserted by the bedside nurse and placement was confirmed radiographically.

Results

A total of 104 patients were enrolled, 54 in the gastric group and 50 in the post-pyloric group. Bedside post-pyloric tube insertion was successful in 80% of patients. Patients who failed post-pyloric insertion were fed via the nasogastric route, but were analysed on an intent-to treat basis. A per protocol analysis was also performed. Baseline characteristics were similar for all except Acute Physiology and Chronic Health Evaluation II (APACHE II) score, which was higher in the post-pyloric group. There was no difference in length of stay or ventilator days. The gastric group was quicker to initiate feed 4.3 hours (2.9 - 6.5 hours) as compared to post-pyloric group 6.6 hours (4.5 - 13.0 hours) (P = 0.0002). The time to reach target feeds from admission was also faster in gastric group: 8.7 hours (7.6 - 13.0 hours) compared to 12.3 hours (8.9 - 17.5 hours). The average daily energy and protein deficit were lower in gastric group 73 Kcal (2 - 288 Kcal) and 3.5 g (0 - 15 g) compared to 167 Kcal (70 - 411 Kcal) and 6.5 g (2.8 - 17.3 g) respectively but was only statistically significant for the average energy deficit (P = 0.035). This difference disappeared in the per protocol analysis. Complication rates were similar.

Conclusions

Early post-pyloric feeding offers no advantage over early gastric feeding in terms of overall nutrition received and complications

Trial Registration

Clinical Trial: anzctr.org.au:ACTRN12606000367549

[Promotility drugs use in critical care: indications and limits?]

Enteral feeding is often limited by gastric and intestinal motility disturbances in critically ill patients, particularly in patients with shock. So, promotility agents are frequently used to improve tolerance to enteral nutrition. This review summaries the pathophysiology, presents the available pharmacological strategies, the clinical data, the counter-indications and the principal limits. The clinical data are poor. No study demonstrates a positive effect on clinical outcomes. Metoclopramide and erythromycin seems to be the more effective. Considering the risk of antibiotic resistance, the first line use of erythromycin should be avoided in favor of metoclopramide.

Gastrointestinal complications in critically ill patients: what differs between adults and children?

PURPOSE OF REVIEW

The objective of this review has been to analyse and compare the causes, incidence, severity and treatment of gastrointestinal complications in critically ill children and adults.

RECENT FINDINGS

The incidence of gastrointestinal complications in critically ill patients published in the literature is very variable owing to the absence of unified diagnostic criteria both in children and adults. The incidence of gastrointestinal complications related to nutrition appears to be lower in children than in adults, and there are no differences in the incidence of gastrointestinal complications between gastric and transpyloric nutrition except with respect to the volume of gastric residues. The most important risk factors for digestive tract complications are shock and the administration of drugs (catecholamines, sedatives and muscle relaxants). Altered gastrointestinal motility is the principal mechanism underlying an excessive gastric residue, abdominal distension and constipation.

SUMMARY

Gastrointestinal complications limit the efficacy of enteral nutrition in the critically ill patient and can affect morbidity and mortality. Consensus must be reached on the definition of the criteria of excessive gastric residues, constipation and diarrhoea, and studies must be performed that evaluate the efficacy of prokinetic agents on altered gastrointestinal motility and the effects of diet and laxatives on constipation in the critically ill adult and child.

Continuous intravenous lidocaine in the treatment of paralytic ileus due to severe spinal cord injury

Paralytic ileus is a major concern in the acute phase of spinal cord injury. Classical treatment with neostigmine is often ineffective. Continuous intravenous (i.v.) lidocaine infusion has been previously proposed intra and post-operatively in order to decrease the duration of post-operative ileus after abdominal surgery. We report the cases of seven patients suffering from complete paralytic spinal cord injury-related ileus with colectasy resistant to neostigmine, who were treated by i.v. lidocaine infusion.

Year in review 2007: Critical Care--shock

The research papers on shock published in Critical Care throughout 2007 are related to three major subjects: the modulation of the macrocirculation and microcirculation during shock, focusing on arginine vasopressin, erythropoietin and nitric oxide; studies on metabolic homeostasis (acid–base status, energy expenditure and gastrointestinal motility); and basic supportive measures in critical illness (fluid resuscitation and sedation, and body-temperature management). The present review summarizes the key results of these studies and provides a brief discussion in the context of the relevant scientific and clinical background.

Gastrointestinal motility in acute illness

Critical illness affects gastrointestinal motility - not only as a primary problem, which brings the patient to the intensive care unit (ICU), but also as a complication consecutive to the ICU stay. Motility disturbances may result from impaired function of gastrointestinal muscle, pacemaker cell function and nerve activity. The most important neural control system is the enteric nervous system that contains the largest collection of neurons (10(8) cells) outside the central nervous system. Through its organization it can operate independently of the brain and generate motility patterns according to need: a postprandial motility pattern starting after food intake, and an interdigestive motility pattern starting several hours after a meal. Undisturbed intestinal motility depends critically on a balanced interaction between inhibition and excitation, and a disturbance in this balance leads to severe derangements of intestinal motility. These motility disturbances differ in clinical appearance and location but can affect all parts of the gastrointestinal tract. This review focuses on select motility disturbances such as gastroparesis, postoperative ileus, and Ogilvie's syndrome. Generally effective methods to treat these conditions are given. Finally, we focus on special management options to prevent such motility disturbances or to reduce their severity.

Influence of temporary abdominal wall repair on the intestinal integrity: an experimental study in the rat

BACKGROUND AND AIMS

The aim of this study was to analyze intestinal integrity after temporary abdominal wall repair with absorbable mesh.

METHODS

Rats underwent abdominal wall repair with absorbable mesh or sham operation. Myeloperoxidase-positive cells in the intestinal muscularis were histochemically quantified. Intestinal transit was visualized 48 h after surgery. Local and systemic inflammatory response was measured with TNF-alpha and IL-6 ELISA as well as malondialdehyde (MDA) expression in serum and peritoneal fluid.

RESULTS

Neutrophil count of the intestinal muscularis revealed that infiltration in the mesh-implanted and in the mesh-free animals 48 h postoperatively was similar. Gastrointestinal transit was similarly unaffected 48 h after surgery, with or without mesh implantation. TNF-alpha, IL-6 and MDA concentration in serum and peritoneal fluid showed no significant differences between the two groups.

CONCLUSION

Intestinal contractility and local and systemic inflammatory response remained unaffected. Therefore, absorbable mesh augmentation is a safe and reliable method for temporary repair of the abdominal wall without affecting the intestinal integrity.