Risk of aspiration in patients on enteral nutrition: frequency, relevance, relation to pneumonia, risk factors, and strategies for risk reduction

Factors Associated with Hospitalized Community-Acquired Pneumonia among Elderly Patients Receiving Home-Based Care

(1) Background: Pneumonia stands as a prevalent infectious disease globally, contributing significantly to mortality and morbidity rates. In Taiwan, pneumonia ranks as the third leading cause of death, particularly affecting the elderly population (92%). This study aims to investigate factors associated with community-acquired pneumonia (CAP) among elderly individuals receiving home-based care. (2) Methods: Conducted between January 2018 and December 2019, this retrospective study involved a medical chart review of elderly patients under home-based care. A multiple logistic regression model was employed to identify factors associated with CAP in this demographic. (3) Results: Analysis encompassed 220 elderly patients with an average age of 82.0 ± 1.1 years. Eighty-five patients (38.6%) were hospitalized for CAP. Predominant diagnoses included cancer (32.3%), stroke (24.5%), and dementia (23.6%). Significant predictors of CAP for elderly patients under home-based care included male gender (odds ratio [OR] = 4.10, 95% confidence interval [CI]: 1.95-8.60, p < 0.001), presence of a nasogastric (NG) tube (OR = 8.85, 95% CI: 3.64-21.56, p < 0.001), and a borderline negative association with the use of proton pump inhibitors (PPIs) (OR = 0.37, 95% CI: 0.13-1.02, p = 0.0546). End-of-life care indicators for these patients with CAP included an increased number of hospital admission days in the last month of life (OR = 1.13, 95% CI: 1.08-1.18, p < 0.001) and a higher likelihood of hospital death (OR = 3.59, 95% CI: 1.51-8.55, p = 0.004). (4) Conclusions: In the current study, significant predictors of CAP among elderly patients receiving home-based care included the presence of an NG tube and male gender, while the use of PPIs was borderline inversely associated with the risk of CAP. Notably, more admission days in the last month of life and death in the hospital were found to be associated with end-of-life care for this group.

Aspiration pneumonia in enteral feeding: A review on risks and prevention

Enteral feeding plays a critical role in the management of hospitalized patients, especially in intensive care units. In addition to delivering important nutrients, it also maintains the integrity of the gut and microbiota. Enteral feeding is also associated with complications and adverse events, some are related to access placement, metabolic and electrolytes disturbances, and aspiration pneumonia. In tube-fed patients, aspiration pneumonia has a prevalence ranging from 4% to 95% with a mortality rate of 17%-62%. Our review has not showed any significant difference in the incidence of aspiration pneumonia between gastric and postpyloric feeding and, given the ease of gastric access, we therefore suggest using gastric feeding as an initial strategy for the delivery of nutrition unless postpyloric access is otherwise indicated for other clinical reasons.

Predictors of aspiration pneumonia: developing a new matrix for speech and language therapists

INTRODUCTION

The contributing factors of aspiration pneumonia have been well documented. However, there are gaps in the literature regarding identifying the weight associated with each factor and the relationship between factors.

METHOD

In this study, 20 potential predictors of aspiration pneumonia (with four additional variables) have been applied to historic Speech and Language Therapy records to greater understand the significance of each contributor of aspiration pneumonia. 152 cases with an oropharyngeal dysphagia, and a Speech and Language Therapy recommendation of eating and drinking with known aspiration and the associated potential risk of developing an aspiration pneumonia, were included in the data. These were inpatients and outpatients, and had various diagnoses but all had had a videofluoroscopy.

RESULTS

Logistic regression analysis found seven factors that were individually significant in predicting the development of aspiration pneumonia with 84.93% sensitivity and 91.03% specificity DISCUSSION: Logistic regression and random forest analyses led to the proposal of a new matrix of predictors of aspiration pneumonia with respective scoring weights for individual and cumulative contributors (a direction for future research).

Incidence and risk factors of nasogastric feeding intolerance in moderately-severe to severe acute pancreatitis

Background

The importance of enteral nutrition (EN) in acute pancreatitis (AP) has been emphasised. Nasogastric (NG) feeding has been the preferred route for EN delivery in most AP patients intolerant to oral intake. However, gastric feeding intolerance (GFI) was frequently reported, especially in patients with more severe diseases. This study aimed to investigate the incidence and risk factors for GFI in moderately-severe to severe AP.

Methods

This is a single-centre, retrospective study. All the data were extracted from an electronic database from April 2020 to May 2021. Data were prospectively collected during hospitalisation. Patients diagnosed with moderately-severe to severe AP and admitted within seven days from the onset of abdominal pain were assessed for eligibility. Patients who showed signs of intolerance to gastric feeding and required switching to nasojejunal (NJ) feeding were deemed GFI. Multivariable logistic regression was performed to assess potential risk factors of GFI.

Results

A total of 93 patients were analysed, of whom 24 were deemed GFI (25.8%), and the rest tolerated NG feeding well (n = 69). In patients with GFI, the median time of switching to NJ feeding was five days (interquartile range: 4–7 days) after admission. The multivariable analysis showed that respiratory failure (odds ratio = 3.135, 95% CI: 1.111–8.848, P = 0.031) was an independent risk factor for GFI.The mean daily energy delivery in the following three days after switching to NJ feeding was significantly higher than the first three days after initiation of NG feeding in patients with GFI [920.83 (493.33–1326) vs. 465 (252.25–556.67) kcal, P < 0.001].

Conclusion

GFI is common in moderately-severe to severe AP patients with an incidence of 25.8%, and the presence of respiratory failure may increase the risk of GFI.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02403-w.

Intragastric prepyloric enteral nutrition, bolus vs continuous in the adult patient: A systematic review and meta-analysis

Bolus and continuous nutrition are commonly used enteral nutrition (EN) administration methodologies. Currently, there is insufficient evidence to establish which is the most effective method for reducing gastrointestinal complications in adult patients. The aim of this review is to evaluate the impact of bolus/intermittent EN compared with continuous EN for the following outcomes: diarrhea, constipation, emesis/vomiting, gastric residual volume, aspiration, and glycemic control in adult patients receiving intragastric prepyloric EN in the hospital setting. Bibliographical research was performed on the following databases: PubMed, Embase, CINAHL, and the Cochrane Central Register of Controlled Trials. The review included all randomized and nonrandomized controlled trials of patients aged ≥18 years with preserved gastrointestinal function. Meta-analysis was performed by Review Manager V.5.3. Seven studies including 551 patients were included in the meta-analysis. Five of these studies reported that the diarrhea rate was higher in the bolus feeding group (risk ratio [RR] = 2.50; 95% CI, 1.17-5.34; P = 0.02), and another five of these studies indicated that the aspiration rate was higher in the continuous feeding group (RR = 0.55; 95% CI, 0.35-0.87; P = 0.01). There were no significant differences for the other outcomes. In conclusion, intermittent EN appears to reduce the incidence of aspiration in the hospital setting; however, it may increase the risk of diarrhea. For future research, we hypothesize the joint use of continuous nutrition until the patient reaches tolerance and then passing to bolus nutrition, thus reducing the incidence of aspiration and enabling a physiological nutrition intake.

Intermittent versus continuous enteral nutrition on feeding intolerance in critically ill adults: A meta-analysis of randomized controlled trials

OBJECTIVES

Enteral formula delivery strategy is an important part of enteral nutrition. We aimed to synthesize up-to-date studies to clarify the effects of intermittent versus continuous feeding on feeding intolerance during enteral nutrition in critically ill adults.

DESIGN

A meta-analysis of randomized controlled trials.

DATA SOURCES

Embase, PubMed, Information Sciences Institute Web of Science, CINAHL EBSCO, Cochrane Central Register of Controlled Trials, Chinese Biomedical Literature Database, China National Knowledge Infrastructure databases were searched from inception to 17th of June 2020.

REVIEW METHODS

The Cochrane "risk of bias" tool was used to assess the quality of individual studies, and the quality of each outcome was assessed by GRADE approach. Fixed or random effect meta-analysis was used pending the presence of heterogeneity. Dichotomous data synthesis was presented as risk ratio and 95% confidence interval, and quantitative data synthesis was shown as mean difference and 95% confidence interval.

RESULTS

Fourteen trials with 1025 critically ill adults were included in the meta-analysis. We found that intermittent feeding could significantly increase the occurrence of feeding intolerance (risk ratio = 1.64, 95% confidence interval = 1.23 to 2.18, P < 0.001) compared with continuous feeding, as well as the incidence of high gastric volume (risk ratio = 3.62, 95% confidence interval = 1.43-9.12, P = 0.006) and aspiration (risk ratio = 3.29, 95% confidence interval = 1.18-9.16, P = 0.02) in > 1-week trial duration, while constipation rate was reduced in intermittent feeding group (risk ratio = 0.66, 95% confidence interval = 0.45-0.98, P = 0.04). Patients in intermittent feeding group received more calories compared with continuous feeding group (mean difference = 184.81, 95% confidence interval = 56.61-313.01, P = 0.005). The quality of all evidence synthesis was "low" or "very low".

CONCLUSIONS

In critically ill adults, continuous feeding was associated with lower overall incidence of feeding intolerance, especially in high gastric volume and aspiration. However, decreased constipation incidence and more calorie intake were observed in intermittent feeding group. Because quality of the synthesized evidence was "low" or "very low", there is considerable uncertainty about this estimate.

Gastric Flora in Gastrostomy Fed Children with Neurological Impairment on Antacid Medication

This prospective cohort study aimed to: (1) describe types, concentrations and sensitivity profiles of bacteria found in gastric aspirates of neurologically impaired children; (2) compare flora between outpatients and those admitted with aspiration pneumonia; and (3) examine predictors of bacterial colonization. Gastric aspirates from gastrostomy fed, neurologically impaired children on antacid medication were measured for pH and sent for microbiological testing. The outpatient arm included 26 children at their baseline; the inpatient arm included 31 children with a clinical diagnosis of aspiration pneumonia. Descriptive statistics summarized the ecology and resistance patterns of microbial flora. Predictors of total bacterial colonization were explored with linear regression. High concentrations of potentially pathogenic fecal-type bacteria were detected in 50/57 (88%) gastric aspirates. pH was found to be the only predictor of bacterial growth; children with gastric pH ≥ 4 had significantly higher concentrations of aerobic growth, while those with no bacterial growth had a pH < 4. Further studies to evaluate optimal gastric pH, the role of gastric bacteria in causing aspiration pneumonia, and the optimal empiric therapy for aspiration pneumonia are recommended.

Factors associated with hospitalization for community-acquired pneumonia in home health care patients in Taiwan

BACKGROUND

Pneumonia is a leading cause of hospitalization and death worldwide. However, studies focusing on risk factors of community-acquired pneumonia (CAP) in the home health care (HHC) population remain scarce.

AIMS

This study aimed to evaluate risk factors associated with hospitalization for CAP among HHC patients in Taiwan.

METHODS

This retrospective cross-sectional study extracted data from patients' electronic medical records between 1 January 2017 and 31 December 2017. Multiple logistic regression analyses were performed to explore factors associated with hospitalization for CAP.

RESULTS

In total, 598 patients (men/women: 236/362) were included. One hundred ninety-nine patients (33.28%) were hospitalized for pneumonia. Inpatients showed a higher proportion of the following: male sex, functional impairment, hypoalbuminemia, anemia, nasogastric tube use, excessive polypharmacy, stroke, dementia, heart failure, chronic respiratory disease, and chronic liver disease. Furthermore, nasogastric tube use (odds ratio [OR] 3.01, 95% confidence interval [CI] 1.88-4.82), anemia (OR 2.37, 95% CI 1.48-3.80), male sex (OR 2.14, 95% CI 1.43-3.20), chronic respiratory disease (OR 2.09, 95% CI 1.33-3.30), dementia (OR 1.94, 95% CI 1.27-2.97), heart failure (OR 1.69, 95% CI 1.11-2.56), and hypoalbuminemia (OR 1.57, 95% CI 1.03-2.40) significantly increased the risk of hospitalization for CAP.

CONCLUSIONS

Our results revealed risk factors associated with hospitalization for CAP in HHC patients. In addition to chronic diseases, malnutrition is an important risk factor. Caregivers should make prompt assessments and take preventive measures for such patients.

A comparative study of risk of pneumonia and mortalities between nasogastric and jejunostomy feeding routes in surgical critically ill patients with perforated peptic ulcer

INTRODUCTION

Enteral nutrition (EN) is important in the management of critically illness. Yet, the best route (e.g. pre-pyloric or post-pyloric) for EN in critically ill patients remains to be investigated, especially in specific surgical patients group. In addition, EN could be associated with a higher risk of aspiration pneumonia. Therefore, we evaluate the effect of various EN routes in surgical critically ill perforated peptic ulcer (PPU) patients who underwent surgery and required mechanical ventilation.

METHOD

We collected data of surgical critically ill PPU patients admitted to intensive care unit. The patients were managed with appropriate care bundle and program. To reduce the impact of surgery types, we excluded those who had received other surgical procedures and included patients that only received simple closure. Patients were classified into nasogastric and jejunostomy feeding groups. The demographics, severity scores (e.g.: APACHE II, SOFA, and POSSUM), body mass index (BMI), comorbidities, ventilator days, use of proton pump inhibitors (PPIs), pneumonia occurrence, mortality and complications were collected for analysis.

RESULTS

A total of 136 critically ill PPU patients that received surgery and mechanical ventilation were enrolled. There were 53 patients in NG group and 83 patients in FJ group. There were no differences in demographics, severity scores, BMI, comorbidities, ventilator days, use of PPIs, pneumonia occurrence, mortalities and complications between groups.

CONCLUSION

Our study indicates that there are no differences in mortalities and pneumonia occurrence using nasogastric or feeding jejunostomy in surgical critically ill PPU patients underwent surgery. However, further studies are required.

An Algorithmic Approach to Nutritional Difficulties in People With Developmental Disabilities

With the increasing survival rate of people with developmental disabilities into adulthood and later life, nutritional support and feeding of these individuals frequently becomes a critical problem which must be addressed by their caregivers and healthcare providers. Problems surrounding mealtimes include difficulty with the mechanisms of feeding as well as medical complications including aspiration and gastrointestinal dysmotility. No comprehensive guidelines exist to aid caregivers and healthcare providers regarding the issues in feeding and nutrition in this population. We offer an algorithmic approach to the nutrition-related problems of aspiration, laborious meals and mealtime refusal, choosing the best route for tube feeding, and when to return patients with developmental disabilities back to oral feeding.

Differences in the incidence of postoperative pneumonia after percutaneous endoscopic gastrostomy between liquid and semi-solid nutrient administration

BACKGROUND/OBJECTIVES

This historical control study examined the differences in the incidence of postoperative pneumonia between patients administered liquid and semi-solid nutrients after percutaneous endoscopic gastrostomy (PEG).

SUBJECTS/METHODS

The medical records of adult patients who underwent PEG between March 1999 and March 2014 were investigated. The patients were administered either liquid or semi-solid nutrient and examined for gastroesophageal reflux via radiography after PEG. The study period was divided into periods I (liquid nutrient to all patients), II (semi-solid nutrient to patients with reflux and liquid nutrient to those without), and III (semi-solid nutrient to all patients). The patient characteristics and incidence of postoperative pneumonia were stratified by the periods. To assess the relationship between postoperative pneumonia and the periods, a logistic regression analysis was performed.

RESULTS

Of 370 patients enrolled, 149 were in period I, 64 in period II, and 157 in period III. Postoperative pneumonia was more frequently observed in period I (20.8%) than in periods II (7.8%) and III (10.2%). The odds ratios were higher in period I (period I vs. II: 3.10 [95% confidence intervals: 1.15-8.38]; period I vs. III: 2.32 [1.21-4.44]). The incidence of gastroesophageal reflux did not greatly differ between periods II (25.0%) and III (35.0%).

CONCLUSIONS

The incidence of postoperative pneumonia after PEG was lower in the patients administered semi-solid nutrient than in those administered liquid nutrient, suggesting that semi-solid nutrient administration to patients with PEG tubes is preferable to prevent postoperative pneumonia. Furthermore, it may be favored especially in those with gastroesophageal reflux.

Upper esophageal sphincter augmentation reduces pharyngeal reflux in nasogastric tube-fed patients

OBJECTIVES/HYPOTHESIS

Aspiration of gastric refluxate is one of the most commonly observed complications among long-term nasogastric tube (NGT) fed patients. The upper esophageal sphincter (UES) pressure barrier is the main defense mechanism against pharyngeal reflux of gastric contents. Our objective was to investigate the efficacy and safety of the UES assist device (UES-AD) in preventing gastric reflux through the UES in long-term NGT-fed patients.

STUDY DESIGN

Self-Controlled Case series.

METHODS

We studied 10 patients (mean age = 90.6 ± 3.4 years, four females) with dysphagia caused by stroke or dementia who were fed for 0.5 to 5 years (median = 3 years) by NGT. External pressures of 20 to 30 mm Hg were applied by using a handmade UES-AD, which was started 2 hours after the beginning of NGT infusion and was alternated between periods of 2 hours on and 2 hours off, for a total of 12 hours. Placement of the impedance sensors within the UES was guided by high-resolution manometry. Trans-UES and intraesophageal reflux events were recorded by using 24-hour combined pH-impedance measurements.

RESULTS

No aspiration pneumonia events were noted in the period 1 month before or during the study in any of the cohort. Baseline UES pressure averaged 17.5 ± 9.4 mm Hg and was increased to 38.9 ± 11.9mm Hg after application of the UES-AD. Overall frequency of trans-UES reflux decreased significantly with the UES-AD compared to without (0.8 ± 0.9 vs. 3.3 ± 2.8, P < .05 for the 12-hour study period). There was no effect of the UES-AD on esophageal reflux events (7.4 ± 4.4 vs. 6.4 ± 3.0, P > .05).

CONCLUSIONS

UES-AD significantly decreases the number of trans-UES reflux events and can potentially reduce the aspiration risk associated with NGT feeding.

LEVEL OF EVIDENCE

4. Laryngoscope, 128:1310-1315, 2018.

Safety of minimizing preoperative starvation in critically ill and intubated trauma patients

BACKGROUND

Cessation of enteral nutrition prior to an operation/procedure is the most common reason for feeding interruption in critically ill trauma patients and contributes to substantial calorie deficits. This study reports on a strategy to increase calorie intake by continuing feeds until transfer for operations/procedures.

METHODS

Nutrition guidelines were modified in 2006 to allow continuation of feeding in intubated patients up until transfer to the operating room. Prior to 2006, enteral feeding was stopped at least 6 hours prior to surgery. A retrospective cohort design from 2003 to 2010 compared clinical outcomes in groups of adult trauma subjects before and after guideline changes and in subjects at other centers without guideline changes.

RESULTS

During the first week, subjects in the preimplementation cohort (n = 245) received a median of 3,787 kcal per person per week, while subjects in the postimplementation cohort (n = 368) received a median of 6,662 kcal per person per week (p < 0.001). There was no change in calorie intake for subjects at other centers (n = 1,002). The risks of acute respiratory distress syndrome, pneumonia, and mortality were decreased after implementation relative to the preimplementation cohort (acute respiratory distress syndrome: relative risk ratio [RR], 0.69; 95% confidence interval [CI], 0.59-0.81; pneumonia: RR, 0.82; 95% CI, 0.65-1.00; mortality: RR, 0.67; 95% CI, 0.46-0.99). Ventilator-free days increased by 1.4 days (95% CI, 0.1-2.7), while intensive care unit stay and hospital length of stay were unchanged. These outcomes showed similar trends over time at other participating centers.

CONCLUSIONS

Allowing intubated trauma patients to continue enteral nutrition until transfer for operations or procedures was associated with increased caloric intake without evidence of increased pulmonary complications. This represents an important strategy to reduce calorie deficits in the trauma intensive care unit.

LEVEL OF EVIDENCE

Therapeutic study/care management, level III.

Enteral nutrition volume is not correlated with lower respiratory tract infection in patients on mechanical ventilation

OBJECTIVE

To evaluate the effect of enteral nutrition volume, gastrointestinal function and the type of acid suppressive drug upon the incidence of lower respiratory tract infections in critically ill patients on mechanical ventilation (MV).

DESIGN

A retrospective secondary analysis was carried out.

SETTING

The Intensive Care Unit of a University Hospital.

PATIENTS OR PARTICIPANTS

Patients≥18-years-old expected to need MV for more than four days, and receiving enteral nutrition by nasogastric tube within 24h of starting MV.

INTERVENTIONS

We correlated enteral nutrition volume administered during the first 10 days, gastrointestinal function and the type of acid suppressive therapy with the episodes of lower respiratory tract infection up until day 28. Cox proportional hazards ratios in univariate and adjusted multivariate models were used. Statistical significance was considered for p<0.05.

MAIN VARIABLES OF INTEREST

Lower respiratory tract infection episodes.

RESULTS

Sixty-six out of 185 patients (35.7%) had infection; 27 patients had ventilator-associated pneumonia; and 39 presented ventilator-associated tracheobronchitis. Uninfected and infected groups were similar in terms of enteral nutrition volume (54±12 and 54±9mL/h; p=0.94) and caloric intake (19.4±4.9 and 19.6±5.2kcal/kg/d; p=0.81). The Cox proportional hazards model showed neurological indication of MV to be the only independent variable related to infection (p=0.001). Enteral nutrition volume, the type of acid suppressive therapy, and the use of prokinetic agents were not significantly correlated to infection.

CONCLUSIONS

Enteral nutrition volume and caloric intake, gastrointestinal dysfunction and the type of acid suppressive therapy used were not associated to lower respiratory tract infection in patients on MV.

Methods used by critical care nurses to verify feeding tube placement in clinical practice

BACKGROUND

The American Association of Critical-Care Nurses practice alert on verification of feeding tube placement makes evidence-based practice recommendations to guide nursing management of adult patients with blindly inserted feeding tubes. Many bedside verification methods do not allow detection of improper positioning of a feeding tube within the gastrointestinal tract, thereby increasing aspiration risk.

OBJECTIVES

To determine how the expected practices from the American Association of Critical-Care Nurses practice alert were implemented by critical care nurses.

METHODS

This study was part of a larger national, online survey that was completed by 370 critical care nurses. Descriptive statistics were used to analyze the data.

RESULTS

Seventy-eight percent of nurses used a variety of methods to verify initial placement of feeding tubes, although 14% were unaware that tube position should be confirmed every 4 hours. Despite the inaccuracy of auscultation methods, only 12% of nurses avoided this practice all of the time.

CONCLUSIONS

Implementation of expected clinical practices from this guideline varied. Nurses are encouraged to implement expected practices from this evidence-based, peer reviewed practice alert to minimize risk for patient harm.

Interruptions in enteral nutrition delivery in critically ill patients and recommendations for clinical practice

Malnutrition is common in critically ill patients and is associated with poor outcomes for patients and increased health care spending. Enteral nutrition is the method of choice for nutrition delivery. Enteral nutrition delivery practices vary widely, and underfeeding is widespread in critical care. Interruptions in enteral nutrition due to performance of procedures, positioning, technical issues with feeding accesses, and gastrointestinal intolerance contribute to underfeeding. Strategies such as head-of-bed positioning, use of prokinetic agents, tolerance of higher gastric residual volumes, consideration of postpyloric feeding access, and use of a nutrition support protocol may decrease time spent without nutrition.

Gastropulmonary Route of Infection and the Prevalence of Microaspiration in the Elderly Patients with Ventilator-Associated Pneumonia Verified by Molecular Microbiology-GM-PFGE

Gastropulmonary route of infection was considered to be an important mechanism of ventilator-associated pneumonia (VAP). However there is little evidence to support this assumption. Moreover, the prevalence of microaspiration in elderly ventilated patients was not well understood. To confirm gastropulmonary infection route and investigate the prevalence of microaspiration in elderly ventilated patients using genome macrorestriction-pulsed field gel electrophoresis (GM-PFGE). Patients over 60 years old, expected to receive mechanical ventilation longer than 48 h, were prospectively enrolled from October 2009 to January 2012. Clinical data were collected and recorded until they died, developed pneumonia, or were extubated. Samples from gastric fluid, subglottic secretion and lower respiratory tract (LRT) were collected during the follow-up for microbiological examination. To evaluate the homogeneity, GM-PFGE was performed on strains responsible for VAP that had the same biochemical phenotype as those isolated from gastric juice and subglottic secretions sequentially. Among 44 VAP patients, 76 strains were isolated from LRT and considered responsible for VAP. Twenty-two isolates had the same biochemical phenotype with the corresponding gastric isolates. The homology was further confirmed using GM-PFGE in 12 episodes of VAP. Nearly 30% of VAPs were caused by microaspiration based on the analysis of bacterial phenotype or GM-PFGE. In addition, 58.3% patients with gastric colonization developed VAP, especially late-onset VAP (LOP). Gastropulmonary infection route exists in VAP especially LOP in elderly ventilated patients. It is one of the important mechanisms in the development of VAP.

Aspiration pneumonia: a review of modern trends

PURPOSE

The purpose was to describe aspiration pneumonia in the context of other lung infections and aspiration syndromes and to distinguish between the main scenarios commonly implied when the terms aspiration or aspiration pneumonia are used. Finally, we aim to summarize current evidence surrounding the diagnosis, microbiology, treatment, risks, and prevention of aspiration pneumonia.

MATERIALS AND METHODS

Medline was searched from inception to November 2013. All descriptive or experimental studies that added to the understanding of aspiration pneumonia were reviewed. All studies that provided insight into the clinical aspiration syndromes, historical context, diagnosis, microbiology, risk factors, prevention, and treatment were summarized within the text.

RESULTS

Despite the original teaching, aspiration pneumonia is difficult to distinguish from other pneumonia syndromes. The microbiology of pneumonia after a macroaspiration has changed over the last 60 years from an anaerobic infection to one of aerobic and nosocomial bacteria. Successful antibiotic therapy has been achieved with several antibiotics. Various risks for aspiration have been described leading to several proposed preventative measures.

CONCLUSIONS

Aspiration pneumonia is a disease with a distinct pathophysiology. In the modern era, aspiration pneumonia is rarely solely an anaerobic infection. Antibiotic treatment is largely dependent on the clinical scenario. Several measures may help prevent aspiration pneumonia.

Gastric emptying and duodenal motility upon intake of a liquid meal with monosodium glutamate in healthy subjects

Glutamate is thought to serve as a special signal for gut functions. We investigated the effects of monosodium l‐glutamate (MSG) on gastric emptying and duodenal motility. Ten healthy male volunteers underwent rapid magnetic resonance imaging (MRI) of the abdomen. Coronal images were successively acquired after ingestion of liquid meal (200 kcal in 200 mL: 9 g protein, 28.4 g carbohydrate, 5.6 g fat, 370 mg Na⁺) with and without 0.5% MSG. During the acquisition of MRI, participants breathed freely. In all participants, the gastric residual volume gradually decreased to 80.1 ± 14.2% without MSG and to 75.9 ± 14.3% with MSG after 60 min (P = 0.45 between the groups, n = 10). In two of 10 participants, gastric emptying slowed down significantly, whereas in the remaining eight participants, gastric residual volume decreased to 84.0 ± 13.1% without MSG, and to 73.0 ± 14.6% with MSG after 60 min (P = 0.015, n = 8). There was no difference in the shape of the stomach between groups. In four of the eight participants responding positively to MSG, the duodenum wall was sufficiently identified to quantify the motions. The inclusion of MSG enhanced duodenal motility, judging from changes in (1) the magnitude of the duodenal area, (2) the center of gravity, and (3) the mean velocity of the wall motions. The third parameter most significantly indicated the excitatory effect of l‐glutamate on duodenum motility (~ three‐ to sevenfold increase during 60 min, P < 0.05, n = 4). These results suggest that MSG accelerates gastric emptying by facilitating duodenal motility, at least in subjects with positive responses to MSG.

The gut and brain share many neurotransmitters and hormones, thereby gut motility frequently reflects mental conditions in humans. So far, procedures to quantify gut motility in vivo have not yet been established. This study of abdominal rapid magnetic resonance imaging (MRI) demonstrates that monosodium L‐glutamate (MSG) accelerates gastric emptying by facilitating duodenal motility, at least in subjects with positive responses to MSG.

A novel protein mixture containing vegetable proteins renders enteral nutrition products non-coagulating after in vitro gastric digestion

BACKGROUND & AIMS

Non-coagulation of protein from enteral nutrition (EN) in the stomach is considered to improve gastric emptying and may result in reduced upper gastrointestinal complications such as reflux and aspiration pneumonia. For the development of a new EN protein mixture with reduced gastric coagulation, the coagulating properties of individual proteins, a novel blend of four proteins (P4 protein blend) and commercial EN products were investigated.

METHODS

A semi-dynamic, computer controlled setup was developed to mimic gastric digestion. The coagulation behaviour of 150 ml protein solutions and EN products was investigated. These were heat-treated calcium caseinate, sodium caseinate, whey, soy and pea protein, and the P4 protein blend comprising of the latter four (all solutions 6% w/v protein), four new enteral nutrition product varieties (New Nutrison® .0 or 1.5 kcal/ml, with and without MultiFibre MF6™) based on the P4 protein blend and two other commercially available casein dominant EN products (T1 and T2).

RESULTS

Calcium caseinate and sodium caseinate yielded a total wet coagulate of 43.5 ± 0.7 g and 52.7 ± 6.2 g, respectively. Whey, soy, pea and the P4 protein blend did not produce any measurable coagulate. T1 and T2 resulted in a total wet coagulate of 37.5 ± 0.8 g and 57.3 ± 0.8 g, respectively, while all new EN product varieties based on the P4 protein blend did not produce any measurable coagulate.

CONCLUSIONS

The P4 protein blend renders EN product varieties non-coagulating after in vitro gastric digestion.

The effect of gastric juice on interleukin-8 production by cystic fibrosis primary bronchial epithelial cells

CF patients are often treated with proton pump inhibitors (PPIs) to reduce acidic gastro-esophageal reflux (GER) and bronchial aspiration of duodeno-gastric contents is common in CF. We have previously demonstrated that gastric juice (GJ) from patients "on" PPI can induce interleukin-8 (IL-8) production by bronchial epithelial cells in culture. We hypothesized that such effect would be more pronounced in CF patients known to have high inflammatory susceptibility. We aimed to evaluate the effect of GJ on IL-8 production by primary bronchial epithelial cells (PBEC), derived from a CF patient and a healthy subject.

METHODS

PBEC obtained from one donor (normal PBEC) and one receptor (CF-PBEC) for lung transplantation were stimulated with GJ from patients "off" and "on" PPI. IL-8 levels were measured in the supernatant.

RESULTS

GJ from patients "on" PPI provoked a significant higher IL-8 production compared to GJ from patients "off" PPI, both in normal PBEC [462 (200-1468) vs. 11 (4-28) pg/ml, p=0.0001] as in CF-PBEC [1468 (841-2449) vs. 85 (26-131) pg/ml, p<0.0001]. Exposure of the cells to GJ "off" PPI and "on" PPI provoked significantly higher IL-8 production in the CF-PBEC compared to the normal PBEC ["off" PPI 85 (26-131) vs. 11 (4-28) pg/ml, p=0.01; "on" PPI 1468 (841-2449) vs. 462 (200-1468) pg/ml, p=0.01]. Filtration (0.20 μm) of the GJ "on" PPI, to eliminate large particles and bacterial sub-products, resulted in a significant decrease of IL-8 production.

CONCLUSION

Patients with CF, treated with PPIs, have GJ with high pH and high endotoxin levels. These patients often have GER and bronchial aspiration. The aspirated material (GJ "on" PPI) has a significantly enhanced inflammatory effect on CF bronchial epithelial cells in culture. As chronic PPI treatment in CF may result in a paradoxically increased inflammatory effect in the airways, alternative anti-reflux therapies should be considered in CF.

Gastric juice from patients "on" acid suppressive therapy can still provoke a significant inflammatory reaction by human bronchial epithelial cells

BACKGROUND

Patients with reflux-related respiratory symptoms are frequently treated with proton pump inhibitors (PPI). It is unclear whether aspiration of gastric juice (GJ) from patients "on" PPI can provoke a similar bronchial inflammatory reaction than that observed in patients "off" medication. The goal of this study was to evaluate the effect of GJ from patients with and without PPI treatment on production of IL-8 by human primary bronchial epithelial cells (PBEC).

STUDY

PBEC were exposed during 24 hours to GJ (1/1000) from patients "on" (n=10) and "off" (n=13) PPI and to nonacidic gastric components (pepsin and bile acids). IL-8 concentration in supernatant was measured with enzyme-linked immunosorbent assay. Endotoxin level in GJ samples was analyzed with a LAL assay.

RESULTS

Exposure of PBEC to GJ from patients "on" PPI provoked a higher production of IL-8 than GJ from patients "off" PPI [279 pg/mL (36 to 498) vs. 11 pg/mL (9 to 27)]. A correlation was found between pH of GJ and IL-8 production (r=0.659, P=0.0006). No correlation was found between IL-8 production and concentration of bile acids or pepsin. Filtration (0.20 [mu]m) of GJ from patients "on" PPI reduced IL-8 production. A positive correlation was found between IL-8 production and endotoxin levels of GJ samples (1/1000) (r=0.654, P=0.0007).

CONCLUSIONS

Exposure of bronchial epithelial cells to GJ from patients "on" PPI is able to induce high IL-8 production. These results suggest that aspiration of GJ in patients treated with PPI might still be able to provoke a significant bronchial inflammatory reaction.

Institutional practices of withholding enteral feeding from intubated patients

OBJECTIVE

This study compared the practices of anesthesia, anesthesia critical care, surgical critical care, and medical critical care departments that have training programs for the length of time they withhold enteral feeding from intubated patients before seven scheduled procedures: 1) extubation; 2) tracheostomy; 3) abdominal surgery; 4) nonabdominal surgery; 5) magnetic resonance imaging or computerized tomography; or placing the patient in the 6) Trendelenberg or 7) prone position.

DESIGN

One-time survey of 297 anesthesia and critical care training programs in the United States.

MEASUREMENTS AND MAIN RESULTS

Eighty programs responded (27%). We compared the median hours of withholding enteral feeding of intubated patients according to training program type for each of the procedures. None of the programs withheld enteral feeds from intubated patients scheduled for magnetic resonance imaging/computerized tomography scans, nor for the Trendelenberg position (median = 0 hour). A significant difference among program types was found for extubation, with anesthesia departments having significantly longer times (median = 6 hours) compared with anesthesia critical care (median = 4 hours), surgical critical care (median = 2 hours), and medical critical care (1.5 hours) departments (chi = 8.77, df = 3, p = 0.032). For scheduled tracheostomy, surgical critical care departments reported shorter times (median = 4 hours) than did all other surveyed departments (median = 6 hours) (chi = 7.28, df = 3, p = 0.063).

CONCLUSIONS

Differences in opinion exist among specialty training programs about the length of time necessary for withholding enteral feeding from intubated patients before scheduled procedures, especially extubation and tracheostomy. To resolve physician conflicts and to best serve these patients, best practice guidelines for withholding enteral feeding from intubated patients before scheduled procedures need to be developed jointly by the critical care specialties.

Methods for the assessment of gastric emptying in critically ill, enterally fed adults

Critically ill patients may experience delayed gastric emptying. Patients receiving enteral feeding are monitored closely to detect a delay of gastric emptying, assess feeding tolerance, and prevent aspiration pneumonia. The most common practice for assessing gastric emptying is to measure the aspirated gastric residual volume; however, this is an unreliable method that lacks standardization, fails to differentiate normal digestive secretions from enteral formula, and results in unnecessary interruptions of enteral nutrition. The aim of this review is to identify an alternative method to assess gastric emptying, which should be reliable, sensitive, harmless, feasible, and inexpensive. Several techniques are discussed: scintigraphy, paracetamol absorption test, breath tests, refractometry, ultrasound, and gastric impedance monitoring. Refractometry seems to be the most appropriate tool for the regular assessment of enteral nutrition; however, standardization and validation of this method are needed before it can be routinely used to monitor critically ill patients receiving enteral nutrition.