Altered gastric emptying in the head-injured patient: relationship to feeding intolerance

Observed differences in nutrition management at two time points spanning a decade in critically ill trauma patients with and without head injury

BACKGROUND

Nutritional needs of trauma patients admitted to the intensive care unit may differ from general critically ill patients, but most current evidence is based on large clinical trials recruiting mixed populations.

OBJECTIVE

The aim of the study was to investigate nutrition practices at two time points that span a decade in trauma patients with and without head injury.

METHODS

This observational study recruited adult trauma patients receiving mechanical ventilation and artificial nutrition from a single-centre intensive care unit between February 2005 to December 2006 (cohort 1), and December 2018 to September 2020 (cohort 2). Patients were categorised into head injury and non-head injury subgroups. Data regarding energy and protein prescription and delivery were collected. Data are presented as median [interquartile range]. Wilcoxon rank-sum test assessed the differences between cohorts and subgroups, with a P value ≤ 0.05. The protocol was registered with the Australian and New Zealand Clinical Trials Registry (Trial ID: ACTRN12618001816246).

RESULTS

Cohort 1 included 109 patients, and 112 patients were included in cohort 2 (age: 46 ± 19 vs 50 ± 19 y; 80 vs 79% M). Overall, nutrition practice did not differ between head-injured and non-head-injured subgroups (all P > 0.05). Energy prescription and delivery decreased from time point one to time point two, regardless of subgroup (Prescription: 9824 [8820-10 581] vs 8318 [7694-9071] kJ; Delivery: 6138 [5130-7188] vs 4715 [3059-5996] kJ; all P < 0.05). Protein prescription did not change from time point one to time point two. Although protein delivery remained constant from time point one to time point two in the head injury group, protein delivery reduced in the non-head injury subgroup (70 [56-82] vs 45 [26-64] g/d, P < 0.05).

CONCLUSION

In this single-centre study, energy prescription and delivery in critically ill trauma patients reduced from time point one to time point two. Protein prescription did not change, but protein delivery reduced from time point one to time point two in non-head injury patients. Reasons for these differing trajectories require exploration.

STUDY REGISTRATION

Trial registered at www.anzctr.org.au.

TRIAL ID

ACTRN12618001816246.

Ten good reasons to consider gastrointestinal function after acute brain injury

The brain-gut axis represents a bidirectional communication linking brain function with the gastrointestinal (GI) system. This interaction comprises a top-down communication from the brain to the gut, and a bottom-up communication from the gut to the brain, including neural, endocrine, immune, and humoral signaling. Acute brain injury (ABI) can lead to systemic complications including GI dysfunction. Techniques for monitoring GI function are currently few, neglected, and many under investigation. The use of ultrasound could provide a measure of gastric emptying, bowel peristalsis, bowel diameter, bowel wall thickness and tissue perfusion. Despite novel biomarkers represent a limitation in clinical practice, intra-abdominal pressure (IAP) is easy-to-use and measurable at bedside. Increased IAP can be both cause and consequence of GI dysfunction, and it can influence cerebral perfusion pressure and intracranial pressure via physiological mechanisms. Here, we address ten good reasons to consider GI function in patients with ABI, highlighting the importance of its assessment in neurocritical care.

Crosstalk Between the Nervous System and Systemic Organs in Acute Brain Injury

Organ crosstalk is a complex biological communication between distal organs mediated via cellular, soluble, and neurohormonal actions, based on a two-way pathway. The communication between the central nervous system and peripheral organs involves nerves, endocrine, and immunity systems as well as the emotional and cognitive centers of the brain. Particularly, acute brain injury is complicated by neuroinflammation and neurodegeneration causing multiorgan inflammation, microbial dysbiosis, gastrointestinal dysfunction and dysmotility, liver dysfunction, acute kidney injury, and cardiac dysfunction. Organ crosstalk has become increasingly popular, although the information is still limited. The present narrative review provides an update on the crosstalk between the nervous system and systemic organs after acute brain injury. Future research might help to target this pathophysiological process, preventing the progression toward multiorgan dysfunction in critically ill patients with brain injury.

Enteral feeding tolerance during pharmacologic neuromuscular blockade

A common misperception is that critically ill patients who receive paralytic therapy will not tolerate enteral nutrition. As a result, some clinicians empirically withhold enteral feedings for critically ill patients who receive neuromuscular blocker pharmacotherapy (NMB). The intent of this review is to examine the evidence regarding enteral feeding tolerance for critically ill patients given NMB. Studies evaluating enteral feeding during paralytic therapy are provided and critiqued. Evidence examining enteral feeding tolerance during NMB is limited. Enteral feeding intolerance is more likely attributable to the underlying illnesses and concurrent opioid analgesia, sedation, and vasopressor therapies. Most critically ill patients can be successfully fed during NMB. Prokinetic pharmacotherapy may be warranted in some patients.

Nutritional Support for Pediatric Severe Traumatic Brain Injury

In critically ill children with severe traumatic brain injury (sTBI), nutrition may help facilitate optimal recovery. There is ongoing research regarding nutritional practices in the pediatric intensive care unit (PICU). These are focused on identifying a patient's most appropriate energy goal, the mode and timing of nutrient delivery that results in improved outcomes, as well as balancing these goals against inherent risks associated with nutrition therapy. Within the PICU population, children with sTBI experience complex physiologic derangements in the acute post-injury period that may alter metabolic demand, leading to nutritional needs that may differ from those in other critically ill patients. Currently, there are relatively few studies examining nutrition practices in PICU patients, and even fewer studies that focus on pediatric sTBI patients. Available data suggest that contemporary neurocritical care practices may largely blunt the expected hypermetabolic state after sTBI, and that early enteral nutrition may be associated with lower morbidity and mortality. In concordance with these data, the most recent guidelines for the management of pediatric sTBI released by the Brain Trauma Foundation recommend initiation of enteral nutrition within 72 h to improve outcome (Level 3 evidence). In this review, we will summarize available literature on nutrition therapy for children with sTBI and identify gaps for future research.

Nutrition Management in Patients With Traumatic Brain Injury: A Narrative Review

Traumatic brain injury (TBI) is a major cause of long-term physical and psychological disability and death. In patients with TBI, undernutrition is associated with an increased mortality rate, more infectious complications, and worse neurologic outcomes. Therefore, timely and effective nutritional therapy is particularly crucial in the management of TBI to improve patients' prognoses. This narrative review summarizes the issues encountered in clinical practice for patients with neurotrauma who receive acute and post-acute in-patient rehabilitation services, and it comprehensively incorporates a wide range of studies, including recent clinical practice guidelines (CPGs), with the aim of better understanding the current evidence for optimal nutritional therapy focused on TBI patients. Recent CPGs were reviewed for 6 topics: 1) hypermetabolism and variation in energy expenditure in patients with TBI, 2) delayed gastric emptying and intolerance to enteral nutrition, 3) decision-making on the route and timing of access in patients with TBI who are unable to maintain volitional intake (enteral nutrition versus parenteral nutrition), 4) decision-making on the enteral formula (standard or immune-modulating formulas), 5) glycemic control, and 6) protein support. We also identified areas that need further research in the future.

Hypermagnesemia and feeding intolerance in preterm infants: a cohort study

BACKGROUND

Feeding intolerance (FI) is a common clinical problem in preterm infants often caused by some neonatal disorders and drugs, including antenatal exposure to magnesium sulfate (MgSO₄ ).

OBJECTIVE

To evaluate the association between hypermagnesemia at birth and FI in preterm infants during the first 72 hours of life.

METHOD

This was a cohort study conducted with preterm infants < 34 weeks of gestation. Infants presenting at least two of the following signs were considered as having FI: vomiting, abdominal distension, the need for continuous intermittent feeding, and delayed meconium passage. Hypermagnesemia was characterized by umbilical serum magnesium levels >2.5 mEq/l.

RESULTS

251 infants were evaluated. The median birth weight and gestational age were 1390 (IQR 1020 -1070) g and 31 (IQR 28-32) weeks, respectively. The FI rate was 17.5%. The exposure rate to MgSO₄ was similar in the tolerant and intolerant groups (53.1% x 63.6%, p=0.204), but hypermagnesemia was more frequent in the FI group (40.9% x 24.2%, p= 0.024). The univariate analysis showed that infants with hypermagnesemia were two-fold more likely to present FI (OR 2.16 95% CI 1.09-4.26). In the multiple logistic regression analysis, we found that hypermagnesemia was independently associated with FI (OR 2.51 - 95% CI 1.06-5.91), as well as maternal diabetes mellitus (OR 2.56 95% CI 1.07 - 6.14), SNAPPE-II (OR 1.051 95% CI 1.025-1.078), and brain hemorrhage (OR 3.61 95% CI 1.31 - 9.91).

CONCLUSION

In addition to other factors, hypermagnesemia at birth was independently associated with early feeding intolerance in preterm infants. This article is protected by copyright. All rights reserved.

Promotion of Regular Oesophageal Motility to Prevent Regurgitation and Enhance Nutrition Intake in Long-Stay ICU Patients. A Multicenter, Phase II, Sham-Controlled, Randomized Trial: The PROPEL Study

OBJECTIVES

To evaluate the effect of esophageal stimulation on nutritional adequacy in critically ill patients at risk for enteral feeding intolerance.

DESIGN

A multicenter randomized sham-controlled clinical trial.

SETTING

Twelve ICUs in Canada.

PATIENTS

We included mechanically ventilated ICU patients who were given moderate-to-high doses of opioids and expected to remain alive and ventilated for an additional 48 hours and who were receiving enteral nutrition or expected to start imminently.

INTERVENTIONS

Patients were randomly assigned 1:1 to esophageal stimulation via an esophageal stimulating catheter (E-Motion Tube; E-Motion Medical, Tel Aviv, Israel) or sham treatment. All patients were fed via these catheters using a standardized feeding protocol.

MEASUREMENTS AND MAIN RESULTS

The co-primary outcomes were proportion of caloric and protein prescription received enterally over the initial 7 days following randomization. Among 159 patients randomized, the modified intention-to-treat analysis included 155 patients: 73 patients in the active treatment group and 82 in the sham treatment group. Over the 7-day study period, the percent of prescribed caloric intake (± SE) received by the enteral route was 64% ± 2 in the active group and 65% ± 2 in sham patients for calories (difference, -1; 95% CI, -8 to 6; p = 0.74). For protein, it was 57% ± 3 in the active group and 60% ± 3 in the sham group (difference, -3; 95% CI, -10 to 3; p = 0.30). Compared to the sham group, there were more serious adverse events reported in the active treatment group (13 vs 6; p = 0.053). Clinically important arrhythmias were detected by Holter monitoring in 36 out of 70 (51%) in the active group versus 22 out of 76 (29%) in the sham group (p = 0.006).

CONCLUSIONS

Esophageal stimulation via a special feeding catheter did not improve nutritional adequacy and was associated with increase risk of harm in critically ill patients.

Nutritional and metabolic supplementation for the injured brain: an update

PURPOSE OF REVIEW

Energy dysfunction is increasingly recognized as a key factor in the pathogenesis of acute brain injury (ABI). This one characterized by a high metabolic rate and nitrogen loss is often associated with an undernutrition support. We review the metabolism evolution and nutritional status in brain injured patient and summarize evidence on nutritional support in this condition.

RECENT FINDINGS

The role of nutrition support for improving prognosis in brain injured patient has been underlined recently. A fast nutrition institution whatever the route is essential to prevent an imbalance in caloric support. Moreover, hypermetabolic state must be prevented with a sufficient nitrogen support. Glycemic control is particularly relevant in this group of patient, with the discovery of new fuel that could potentially improve cerebral metabolism and replace glucose. Few data support also the use of immunonutrition input in this group of patients.

SUMMARY

Nutritional support is a key parameter in brain injured patient and must be initiated quickly to counteract hypermetabolic state by caring to improve caloric and nitrogen input. Recent clinical data support the use of immunonutrition, glutamine and zinc in this particular setting.

Update on pediatric gastroparesis: A review of the published literature and recommendations for future research

BACKGROUND

Due to scarcity of scientific literature on pediatric gastroparesis, there is a need to summarize current evidence and identify areas requiring further research. The aim of this study was to provide an evidence-based review of the available literature on the prevalence, pathogenesis, clinical presentation, diagnosis, treatment, and outcomes of pediatric gastroparesis.

METHODS

A search of the literature was performed using the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines with the following databases: PubMed, EMBASE, Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, Cochrane Central Register of Controlled Trials, and Web of Science. Two independent reviewers screened abstracts for eligibility.

KEY RESULTS

Our search yielded 1085 original publications, 135 of which met inclusion criteria. Most articles were of retrospective study design. Only 12 randomized controlled trials were identified, all of which were in infants. The prevalence of pediatric gastroparesis is unknown. Gastroparesis may be suspected based on clinical symptoms although these are often non-specific. The 4-hour nuclear scintigraphy scan remains gold standard for diagnosis despite lack of pediatric normative comparison data. Therapeutic approaches include dietary modifications, prokinetic drugs, and postpyloric enteral tube feeds. For refractory cases, intrapyloric botulinum toxin and surgical interventions such as gastric electrical stimulation may be warranted. Most interventions still lack rigorous supportive data.

CONCLUSIONS

Diagnosis and treatment of pediatric gastroparesis are challenging due to paucity of published evidence. Larger and more rigorous clinical trials are necessary to improve outcomes.

Approaches to Monitor Circuit Disruption after Traumatic Brain Injury: Frontiers in Preclinical Research

Mild traumatic brain injury (TBI) often results in pathophysiological damage that can manifest as both acute and chronic neurological deficits. In an attempt to repair and reconnect disrupted circuits to compensate for loss of afferent and efferent connections, maladaptive circuitry is created and contributes to neurological deficits, including post-concussive symptoms. The TBI-induced pathology physically and metabolically changes the structure and function of neurons associated with behaviorally relevant circuit function. Complex neurological processing is governed, in part, by circuitry mediated by primary and modulatory neurotransmitter systems, where signaling is disrupted acutely and chronically after injury, and therefore serves as a primary target for treatment. Monitoring of neurotransmitter signaling in experimental models with technology empowered with improved temporal and spatial resolution is capable of recording in vivo extracellular neurotransmitter signaling in behaviorally relevant circuits. Here, we review preclinical evidence in TBI literature that implicates the role of neurotransmitter changes mediating circuit function that contributes to neurological deficits in the post-acute and chronic phases and methods developed for in vivo neurochemical monitoring. Coupling TBI models demonstrating chronic behavioral deficits with in vivo technologies capable of real-time monitoring of neurotransmitters provides an innovative approach to directly quantify and characterize neurotransmitter signaling as a universal consequence of TBI and the direct influence of pharmacological approaches on both behavior and signaling.

The Seventh Organ-Gastrointestinal Tract: Neglect at Your Own Peril!

How to cite this article: Kulkarni AP, Govil D, Gupta S. The Seventh Organ—Gastrointestinal Tract: Neglect at Your Own Peril!. Indian J Crit Care Med 2020;24(Suppl 4):S143–S145.

Pathophysiology and Treatment of Gastrointestinal Motility Disorders in the Acutely Ill

Gastrointestinal dysmotility causes delayed gastric emptying, enteral feed intolerance, and functional obstruction of the small and large intestine, the latter functional obstructions being frequently termed ileus and Ogilvie syndrome, respectively. In addition to meticulous supportive care, drug therapy may be appropriate in certain situations. There is, however, considerable variation among individuals regarding what gastric residual volume identifies gastric dysmotility and would encourage use of a promotility drug. While the administration of either metoclopramide or erythromycin is supported by evidence it appears that, dual-drug therapy (erythromycin and metoclopramide) reduces the rate of treatment failure. There is a lack of evidence to guide drug therapy of ileus, but neither erythromycin nor metoclopramide appear to have a role. Several drugs, including ghrelin agonists, highly selective 5-hydroxytryptamine receptor agonists, and opiate antagonists are being studied in clinical trials. Neostigmine, when infused at a relatively slow rate in patients receiving continuous hemodynamic monitoring, may alleviate the need for endoscopic decompression in some patients.

Gastrointestinal dysmotility in critically ill patients

Gastrointestinal (GI) motility disorders are commonly present in critical illness. Up to 60% of critically ill patients have been reported to experience GI dysmotility of some form necessitating therapeutic intervention. It has been attributed to various factors, related to both the underlying disease and the therapeutic interventions undertaken. The assessment of motility disturbances can be challenging in critically ill patients, as the available tests used to detect abnormal motility have major limitations in the setting of an Intensive Care Unit. Critically ill patients with GI dysmotility require a multifaceted treatment approach that addresses multiple causes and utilizes multiple pharmacological pathways. In this review, we discuss the pathophysiology, assessment and management of GI dysmotility in critically ill patients.

Early low-energy versus high-energy enteral nutrition support in patients with traumatic intracerebral haemorrhage: protocol for a randomised controlled trial

BACKGROUND

Early enteral nutrition (EN) is associated with shorter hospital stay and lower infection and mortality rates in patients with intracerebral haemorrhage. However, high-energy support always causes clinical complications, such as diarrhoea and aspiration pneumonia, and the true benefit of high-energy support in these patients has not been investigated. The appropriate amount of energy support still needs further investigation. Therefore, we are performing a randomised controlled trial to investigate whether early low-energy EN can decrease mortality and feeding-related complications and improve neurological outcomes as compared with high-energy EN in traumatic intracerebral haemorrhage (TICH) patients.

METHODS/ANALYSIS

This is a randomised, single-blind clinical trial performed in one teaching hospital. 220 TICH patients will be randomly allocated to one of two groups in a 1:1 ratio: an intervention group, and a control group. The intervention group will receive early low-energy EN (10 kcal/kg/day) and the control group will receive high-energy EN (25 kcal/kg/day) for 7 days. All these patients will be followed up for 90 days. The primary outcome is all-cause 90-day mortality. Secondary outcomes include the modified Rankin score, Glasgow Outcome Scale (GOS) and the National Institutes of Health Stroke Scale (NIHSS). Outcomes will be assessed at admission, 7, 30 and 90 days after onset of this trial. The safety of EN strategies will be assessed every day during hospitalisation.

ETHICS AND DISSEMINATION

The trial will be conducted in accordance with the Declaration of Helsinki and has been approved by the ethics committee of Dongyang People's Hospital. The findings will be published in peer-reviewed medical journals.

TRIAL REGISTRATION NUMBER

ChiCTR-INR-17011384; Pre-results.

Devices and Techniques for Bedside Enteral Feeding Tube Placement

Enteral feedings are an integral part of care for many hospitalized patients. Accessing the gastrointestinal (GI) tract safely and in a timely manner can be challenging. Various techniques and devices to enhance the safety of bedside feeding tube placement are available for clinicians. Three specific devices are highlighted, including the colorimetric CO(2) detector (CCD), a magnetically guided feeding tube (MGFT), and the electromagnetic tube placement device (ETPD). The CO(2) detector is applied to detect the presence or absence of CO(2), thus assisting in correct placement of the feeding tube tip into the GI tract vs the lung. The MGFT uses a magnetic device to manipulate the feeding tube through the GI tract into the small intestine. The ETPD provides real-time visualization of the feeding tube as it progresses into the small intestine. Training and repetition are essential for safe and successful feeding tube placement, and the highlighted devices can contribute to both of these goals.

Tolerance and Efficacy of Enteral Nutrition in Traumatic Brain–Injured Patients Induced Into Barbiturate Coma

BACKGROUND

There is a paucity of data evaluating the efficacy of nutrition support in traumatic brain-injured patients induced into barbiturate coma for refractory intracranial hypertension. Our objective was to evaluate the efficacy of enteral nutrition in a select group of trauma patients.

METHODS

Prospective data were collected on severe traumatic brain-injured patients over a 4-year period. Patients were stratified by whether or not they were induced into a barbiturate coma. Barbiturate coma was defined as per American Association of Neurological Surgeons (AANS) guidelines. All patients were initially fed via the enteral route via a nasogastric feeding tube. Patients who did not tolerate feedings within 48 hours started receiving prokinetic agents. Feeding tolerance was defined as ability to tolerate enteral feedings with <150 mL of gastric residuals every 6 hours for >72 hours.

RESULTS

Fifty-seven patients were induced into a barbiturate coma. All were victims of blunt-force trauma. Forty-two of 57 (74%) patients were men, with a mean age of 37+/-12 years and a mean injury severity score of 24+/-10. Thirty-eight of the 57 (67%) patients had an isolated traumatic brain injury. All 57 patients failed enteral nutrition via the nasogastric route after the first 48 hours of nutrition initiation after barbiturate coma was fully achieved by protocol criteria. Prokinetic agents demonstrated no improvement in feeding tolerance after the subsequent 48-72 hours. Of the 12 patients who had a postpyloric feeding tube placed, only 25% tolerated enteral nutrition for >48 hours.

CONCLUSIONS

Patients with traumatic brain injury induced into barbiturate coma develop a significant ileus that is refractory to prokinetic agents. Only a marginal improvement is seen when the postpyloric route is obtained. Early parenteral nutrition should be considered in this patient population.

Traumatic Brain Injury in the Pediatric Population

Traumatic brain injury (TBI) is a common injury among children. Most TBIs are mild and do not require hospitalization. However, whether or not the patients require acute hospitalization, TBIs may have long-lasting consequences. There is little research on the nutrient needs of these patients, and recommendations are frequently based on data from adults with TBI. It is clear that calorie and protein needs are elevated with acute TBI. However, calorie needs are also decreased by therapies such as sedation, chemical paralysis, and barbiturate coma. Long-term calorie needs may be lower for "comatose" patients. Enteral feeding is preferred and possible for patients with TBI, though gastric feeding may be problematic in some patients. In the acute phase, patients with TBI can also have dysregulation of fluid and electrolyte balance, which may require alterations in nutrition care. Dysphagia is common after moderately severe TBI and requires a multidisciplinary approach for treatment. Future opportunities for research on pediatric TBI are numerous and may include ongoing clarification of macronutrient needs, as well as investigation into the roles of specific nutrients such as zinc, antioxidants, and anti-inflammatory compounds.

Gastric Dysmotility in Critically Ill Children: Pathophysiology, Diagnosis, and Management

OBJECTIVE

We aimed to review gastric dysmotility in critically ill children: 1) its pathophysiology, with a focus on critical care diseases and therapies that affect gastric motility, 2) diagnostic methodologies, and 3) current and future potential therapies.

DATA SOURCES

Eligible studies were identified from PubMed and MEDLINE.

STUDY SELECTION

Literature search included the following key terms: "gastric emptying," "gastric motility/dysmotility," "gastrointestinal motility/dysmotility," "nutrition intolerance," and "gastric residual volume."

DATA EXTRACTION

Studies since 1995 were extracted and reviewed for inclusion by the authors related to the physiology, pathophysiology, diagnostic methodologies, and available therapies for gastric emptying.

DATA SYNTHESIS

Delayed gastric emptying, a common presentation of gastric dysmotility, is present in up to 50% of critically ill children. It is associated with the potential for aspiration, ventilator-associated pneumonia, and inadequate delivery of enteral nutrition and may affect the efficacy of enteral medications, all of which may be result in poor patient outcomes. Gastric motility is affected by critical illness and its associated therapies. Currently available diagnostic tools to identify gastric emptying at the bedside have not been systematically studied and applied in this cohort. Gastric residual volume measurement, used as an indirect marker of delayed gastric emptying in PICUs around the world, may be inaccurate.

CONCLUSIONS

Gastric dysmotility is common in critically ill children and impacts patient safety and outcomes. However, it is poorly understood, inadequately defined, and current therapies are limited and based on scant evidence. Understanding gastric motility and developing accurate bedside measures and novel therapies for gastric emptying are highly desirable and need to be further investigated.

Measurement of gastric emptying in the critically ill

BACKGROUND & AIMS

Enteral nutrition is important in critically ill patients and is usually administered via a nasogastric tube. As gastric emptying is frequently delayed, and this compromises the delivery of nutrient, it is important that the emptying rate can be quantified.

METHODS

A comprehensive search of MEDLINE/PubMed, of English articles, from inception to 1 July 2014. References of included manuscripts were also examined for additional studies.

RESULTS

A number of methods are available to measure gastric emptying and these broadly can be categorised as direct- or indirect-test and surrogate assessments. Direct tests necessitate visualisation of the stomach contents during emptying and are unaffected by liver or kidney metabolism. The most frequently used direct modality is scintigraphy, which remains the 'gold standard'. Indirect tests use a marker that is absorbed in the proximal small intestine, so that measurements of the marker, or its metabolite measured in plasma or breath, correlates with gastric emptying. These tests include drug and carbohydrate absorption and isotope breath tests. Gastric residual volumes (GRVs) are used frequently to quantify gastric emptying during nasogastric feeding, but these measurements may be inaccurate and should be regarded as a surrogate measurement. While the inherent limitations of GRVs make them less suitable for research purposes they are often the only technique that is available for clinicians at the bedside.

CONCLUSIONS

Each of the available techniques has its strength and limitations. Accordingly, the choice of gastric emptying test is dictated by the particular requirement(s) and expertise of the investigator or clinician.

Gastric vs Small Bowel Feeding in Critically Ill Neurologically Injured Patients: Results of a Multicenter Observational Study

BACKGROUND

To evaluate gastric compared with small bowel feeding on nutrition and clinical outcomes in critically ill, neurologically injured patients.

MATERIALS AND METHODS

International, prospective observational studies involving 353 intensive care units (ICUs) were included. Eligible patients were critically ill, mechanically ventilated with neurological diagnoses who remained in the ICU and received enteral nutrition (EN) exclusively for at least 3 days. Sites provided data, including patient characteristics, nutrition practices, and 60-day outcomes. Patients receiving gastric or small bowel feeding were compared. Covariates including age, sex, body mass index, and Acute Physiology and Chronic Health Evaluation II score were used in the adjusted analyses.

RESULTS

Of the 1691 patients who met our inclusion criteria, 1407 (94.1%) received gastric feeding and 88 (5.9%) received small bowel feeding. Adequacy of calories from EN was highest in the gastric group (60.2% and 52.3%, respectively, unadjusted analysis; P = .001), but this was not significant in the adjusted model (P = .428). The likelihood of EN interruptions due to gastrointestinal (GI) complications was higher for the gastric group (19.6% vs 4.7%, unadjusted model; P = .015). There were no significant differences in the rate of discontinuation of mechanical ventilation (hazard ratio [HR], 0.86; 95% confidence interval [CI], 0.66-1.12; P = .270) or the rate of being discharged alive from the ICU (HR, 0.94; 95% CI, 0.72-1.23; P = .641) and hospital (HR, 1.16; 95% CI, 0.87-1.55; P = .307) after adjusting for confounders.

CONCLUSIONS

Despite a higher likelihood of EN interruptions due to GI complications, gastric feeding may be associated with better nutrition adequacy, but neither route is associated with better clinical outcomes.

Use of wireless motility capsule to determine gastric emptying and small intestinal transit times in critically ill trauma patients

PURPOSE

The purpose of this study is to use a novel wireless motility capsule to compare gastric emptying and small bowel transit times in critically ill trauma patients and healthy volunteers.

MATERIALS AND METHODS

We evaluated gastric emptying, small bowel transit time, and total intestinal transit time in 8 critically ill trauma patients. These data were compared with those obtained in 87 healthy volunteers from a separate trial. Data were obtained with a motility capsule that wirelessly transmitted pH, pressure, and temperature to a recorder attached to each subject's abdomen.

RESULTS

The gastric emptying time was significantly longer in critically ill patients (median, 13.9; interquartile range [IQR], 6.6-48.3 hours) than in healthy volunteers (median, 3.0; IQR, 2.5-3.9 hours), P < .001. The small bowel transit time in critically ill patients was significantly longer than in healthy volunteers (median, 6.7 hours; IQR, 4.4-8.5 hours vs median, 3.8 hours; IQR, 3.1-4.7 hours), P = .01. Furthermore, the capsules passed after 10 (IQR, 8.5-13) days in the critical care group and 1.2 (IQR, 0.9-1.9) days in healthy volunteers (P < .001).

CONCLUSIONS

Both gastric emptying and small bowel transit were delayed in critically ill trauma patients.

Gastrointestinal dysmotility: clinical consequences and management of the critically ill patient

Gastrointestinal dysmotility is a common feature of critical illness, with a number of significant implications that include malnutrition secondary to reduced feed tolerance and absorption, reflux and aspiration resulting in reduced lung function and ventilator-associated pneumonia, bacterial overgrowth and possible translocation causing nosocomial sepsis. Prokinetic agent administration can improve gastric emptying and caloric delivery, but its effect on nutrient absorption and clinical outcomes is, as yet, unclear. Postpyloric delivery of nutrition has not yet been demonstrated to increase caloric intake or improve clinical outcomes.

Gastric pH and motility in a porcine model of acute lung injury using a wireless motility capsule

BACKGROUND

Evaluation of gastric pH and motility in a porcine model of acute lung injury using a novel, wireless motility capsule.

MATERIAL/METHODS

A motility capsule was applied into the stomach of 7 Pietrain pigs with acute lung injury induced by high volume saline lavage. Wireless transmission of pH, pressure and temperature data was performed by a recorder attached to the animal's abdomen. Gastric motility was evaluated using pH and pressure values, and capsule location was confirmed by autopsy.

RESULTS

Gastric pH values were statistically significantly different (P<0.003) in the animals over time and ranged from 1.15 to 9.94 [5.73 ± 0.47 (mean ± SD)] with an interquartile range of 0.11 to 2.07. The capsule pressure recordings ranged from 2 to 4 mmHg [2.6 ± 0.5 mmHg (mean ± SD)]. There was no change in pressure patterns or sudden rise of pH >3 pH units during 24 hours. All animals had a gastroparesis with the capsules located in the stomach as indicated by the pressure and pH data and confirmed by necropsy.

CONCLUSIONS

The preliminary data show that Pietrain pigs with acute lung injury have a high variability in gastric pH and severely disturbed gastric motility.

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.

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.

[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.

Parenteral and enteral nutrition in the management of neurosurgical patients in the intensive care unit

The iatrogenic malnutrition of neurosurgical patients in intensive care units (ICU) is an underestimated problem. It may cause a decrease in plasma albumin and oncotic pressure, leading to an increase in the amount of water entering the brain and increased intracranial pressure (ICP). This study was conducted to test the hypothesis that combined high-protein parenteral and enteral nutrition is beneficial for neurosurgical patients in ICU. A total of 202 neurosurgical patients in ICU (mean age+/-standard deviation, 56 years+/-16 years; male:female=1.2:1) were studied. Two consecutive 1-year time periods were compared, during which two different nutritional regimens were followed. In the first time period (Y1) patients were given a low-protein/high-fat formulation parenterally, followed by a standard enteral regimen. In the second time period (Y2) a protein-rich, combined parenteral and enteral diet was prospectively administered. The Glasgow Outcome Score was measured at 3-6 months after discharge. The following clinical parameters were recorded during the first 2 weeks after admission: ICP; albumin; cholinesterase (CHE); daily hours of ICP > 20 mmHg and cerebral perfusion pressure<70 mmHg; and Acute Physiology and Chronic Health Evaluation II (APACHE II) score. It was found that overall albumin (32.4 g/L+/-4.1g/L vs. 27.5 g/L+/-3.6g/L) and CHE was higher during Y2, although the total energy supply, glucose and fat intake was lower. Higher GOS scores were seen when patients had lower APACHE II scores and received the Y2 nutritional regimen. During Y2, the total hours of ICP > 20 mmHg were fewer. With the Y2 nutrition, maintenance of adequate cerebral perfusion required less catecholamine medication and colloidal fluid replacement. Therefore, adequate nutrition is an important parameter in the management of neurosurgical patients in ICU.

Interstitial glycerol increase in microdialysis after glycerol enema

Microdialysis allows the measurement of extracellular concentrations of various endogenous substances, such as excitotoxic amino acids or metabolic end products. Recent advances in microdialysis techniques have led to widespread use in patients with brain disorders. Microdialysis has proved to be a useful tool for monitoring cerebral biochemical metabolism and secondary brain damage in severe head injury, subarachnoid haemorrhage, stroke, and epilepsy. In our neurosurgical intensive care unit, microdialysis was performed on 42 patients. Four patients received a glycerol enema for therapy of a paralytic ileus. A glycerol peak was observed in both intracerebral and subcutaneous microdialysis occurring three to four hours after the glycerol enema in all four patients. The highest glycerol value was 1187micromol/l cerebral and 2997micromol/l in the subcutaneous tissue. Our study indicates that besides the measurement of serum osmolality and serum glycerol level, microdialysis may be an additional valuable tool to control glycerol therapy in patients with cerebral oedema and elevated intracranial pressure.

Effect of time, injury, age and ethanol on interpatient variability in valproic acid pharmacokinetics after traumatic brain injury

BACKGROUND

Traumatic brain injury (TBI) results in an increase in hepatic metabolism. The increased metabolism is in significant contrast to a large body of in vitro and in vivo data demonstrating that activation of the host-defence response downregulates hepatic metabolism. Theoretically, this occurs because of activation of the pro-inflammatory cytokines tumour necrosis factor-alpha, interferon-gamma, interleukin (IL)-1 and IL-6. As part of a large double-blind, placebo-controlled clinical trial evaluating the use of valproic acid for prophylaxis of post-traumatic seizures, we obtained extensive valproic acid concentration-time data. Valproic acid is a hepatically metabolised, low extraction-ratio drug. Therefore, unbound clearance (CL(u)) is equal to intrinsic or metabolic clearance.

OBJECTIVE

The objective of this study was to evaluate the time-dependent effects of TBI on the pharmacokinetics of total and unbound valproic acid with the goal of identifying patient factors that may predict changes in total clearance (CL) and CL(u). In addition, by determining the factors that influence the magnitude and time course of induction of hepatic metabolism and understanding their interaction with the host-defence mediators, we can further our insight into the mechanism(s) responsible for the changes in CL and CL(u).

STUDY DESIGN

Valproic acid plasma concentration data were obtained from 158 TBI patients. Unbound valproic acid plasma concentrations were estimated using total valproic acid plasma and albumin concentrations following a Scatchard equation binding model previously developed in a subset of TBI patients. The effect of 13 patient factors on CL and CL(u) was evaluated initially in a univariate analysis. The significant factors were then included in a multiple linear regression analysis by use of step-wise selection and forward selection procedures.

RESULTS

CL and CL(u) were significantly increased after TBI in a time-dependent manner. The average increase was >75% by weeks 2 and 3 post-injury. The magnitude of the induction of CL was increased with decreased albumin concentrations, in addition to the presence of ethanol on admission, increased severity of head injury, tube feeding and total parenteral nutrition (TPN). The magnitude of induction of CL(u) was increased by older age, presence of ethanol on admission, increased severity of head injury, tube feeding, TPN, and if the patient had a post-injury neurosurgical procedure. The time to normalisation of CL(u) was significantly longer in patients with head injury plus other injuries compared with those with head injury alone.

CONCLUSIONS

As has been reported with other drugs, TBI results in a significant increase in the metabolism of valproic acid. The patient factors identified in this study that resulted in an increase in the magnitude and time course of the induction of CL(u) (ethanol, older age, presence of a neurosurgical procedure, severity of TBI and presence of multiple non-TBI injuries) have all been reported to cause a shift to the anti-inflammatory mediators IL-4 and IL-10. This suggests that the increase in hepatic metabolism after TBI may be due to the increased presence of anti-inflammatory mediators in contrast to the inhibition effect of the pro-inflammatory mediators in non-TBI inflammation and infection.

The impact of admission diagnosis on gastric emptying in critically ill patients

Introduction

Disturbed gastric emptying (GE) occurs commonly in critically ill patients. Admission diagnoses are believed to influence the incidence of delayed GE and subsequent feed intolerance. Although patients with burns and head injury are considered to be at greater risk, the true incidence has not been determined by examination of patient groups of sufficient number. This study aimed to evaluate the impact of admission diagnosis on GE in critically ill patients.

Methods

A retrospective review of patient demographics, diagnosis, intensive care unit (ICU) admission details, GE, and enteral feeding was performed on an unselected cohort of 132 mechanically ventilated patients (94 males, 38 females; age 54 ± 1.2 years; admission Acute Physiology and Chronic Health Evaluation II [APACHE II] score of 22 ± 1) who had undergone GE assessment by ¹³C-octanoic acid breath test. Delayed GE was defined as GE coefficient (GEC) of less than 3.20 and/or gastric half-emptying time (t50) of more than 140 minutes.

Results

Overall, 60% of the patients had delayed GE and a mean GEC of 2.9 ± 0.1 and t50 of 163 ± 7 minutes. On univariate analysis, GE correlated significantly with older age, higher admission APACHE II scores, longer length of stay in ICU prior to GE measurement, higher respiratory rate, higher FiO₂ (fraction of inspired oxygen), and higher serum creatinine. After these factors were controlled for, there was a modest relationship between admission diagnosis and GE (r = 0.48; P = 0.02). The highest occurrence of delayed GE was observed in patients with head injuries, burns, multi-system trauma, and sepsis. Delayed GE was least common in patients with myocardial injury and non-gastrointestinal post-operative respiratory failure. Patients with delayed GE received fewer feeds and stayed longer in ICU and hospital compared to those with normal GE.

Conclusion

Admission diagnosis has a modest impact on GE in critically ill patients, even after controlling for factors such as age, illness severity, and medication, which are known to influence this function.

Gabapentin in the management of dysautonomia following severe traumatic brain injury: a case series

The pharmacological management of dysautonomia, otherwise known as autonomic storms, following acute neurological insults, is problematic and remains poorly researched. This paper presents six subjects with dysautonomia following extremely severe traumatic brain injury where gabapentin controlled paroxysmal autonomic changes and posturing in the early post-acute phase following limited success with conventional medication regimens. In two subjects, other medications were reduced or ceased without a recurrence of symptoms. It is proposed that medications that can block or minimise abnormal afferent stimuli may represent a better option for dysautonomia management than drugs which increase inhibition of efferent pathways. Potential mechanisms for these effects are discussed.

Percutaneous endoscopic gastrostomy: a safe and effective bridge for enteral nutrition in neurological or non-neurological conditions

Percutaneous endoscopic gastrostomy (PEG) is one of the most commonly used methods for nutritional support in patients who are unable to take food orally. Traditional surgical gastrostomy, percutaneous radiologic gastrostomy, and laparoscopic gastrostomy are the alternatives. The most common indication is neurogenic dysphagia followed by obstructive causes such as head and neck tumors. Ethically justified and clinically comprehensive guidelines should be followed during the decision-making process for PEG tube placement. A limited life expectancy; technical difficulties, such as the inability to bring the anterior gastric wall in apposition to the abdominal wall; or pharyngeal/esophageal obstruction, which compromise tube insertion, peritonitis, and uncorrectable coagulopathy are absolute contraindications. The "pull method" is the first described and still the most performed technique of PEG tube placement. The procedure is simple, safe, and effective and fulfills all requirements to provide an ideal route for nutritional support. This article summarizes the reported experience on PEG in the current literature and discusses its utility in patients with neurological conditions.

Short-term elevation of intracranial pressure does neither influence duodenal motility nor frequency of bolus transport events: a porcine model

Background

Patients with traumatic brain injuries and raised intracranial pressure (ICP) display biphasic response with faster gastric emptying during the early stage followed by a prolonged gastric transit time later. While duodenal contractile activity plays a pivotal role in transpyloric transit we investigated the effects of raised intracranial pressure on duodenal motility during the early phase. In order to exclude significant deterioration of mucosal blood supply which might also influence duodenal motility, luminal microdialysis was used in conjunction.

Methods

During general anaesthesia, 11 pigs (32–37 kg, German Landrace) were instrumented with both a luminal catheter for impedancometry and a luminal catheter for microdialysis into the proximal duodenum. Additionally, a catheter was inserted into the left ventricle to increase the intracranial pressure from baseline up to 50 mmHg in steps of 10 mmHg each hour by injection of artificial cerebrospinal fluid. At the same time, duodenal motility was recorded continuously. Duodenal luminal lactate, pyruvate, and glucose concentrations were measured during physiological state and during elevated intracranial pressure of 10, 20, 30, 40, and 50 mmHg in six pigs. Five pigs served as controls.

Results

Although there was a trend towards shortened migrating motor cycle (MMC) length in pigs with raised ICP, the interdigestive phase I–III and the MMC cycle length were comparable in the groups. Spontaneous MMC cycles were not disrupted during intracranial hypertension. The mean concentration of lactate and glucose was comparable in the groups, while the concentration of pyruvate was partially higher in the study group than in the controls (p < 0.05). This was associated with a decrease in lactate to pyruvate ratio (p < 0.05).

Conclusion

The present study suggests that a stepwise and hourly increase of the intracranial pressure of up to 50 mmHg, does not influence duodenal motility activity in a significant manner. A considerable deterioration of the duodenal mucosal blood flow was excluded by determining the lactate to pyruvate ratio.

Steady-state serum concentrations of progesterone following continuous intravenous infusion in patients with acute moderate to severe traumatic brain injury

Progesterone (PG) has been shown to provide substantial neuroprotection after traumatic brain injury (TBI) in multiple animal models. As a first step in assessing applicability to humans, the authors examined the effects of acute TBI and extracranial trauma on the pharmacokinetics of PG given by intravenous infusion. Multiple blood samples were obtained from 11 female and 21 male trauma patients receiving PG and 1 female and 3 male patients receiving placebo infusions for 72 hours. Values for C(SS), CL, t(1/2), and Vd were obtained using AUC((0-72)) and postinfusion blood samples. C(SS) values were 337 +/- 135 ng/mL, which were significantly lower than the target concentration of 450 +/- 100 ng/mL. The lower C(SS) is attributed to the CL, which was higher than anticipated. In addition, t(1/2) was longer and V(d) was higher than anticipated. These results demonstrate that stable PG concentrations can be rapidly achieved following TBI.