Pharmacologic prevention of aspiration pneumonia: a systematic review

Medications to Modify Aspiration Risk: Those That Add to Risk and Those That May Reduce Risk

Aspiration pneumonia results from the abnormal entry of fluids into the respiratory tract. We present a review of drugs known to affect the risk of aspiration. Drugs that increase the risk of aspiration pneumonia can be broadly divided into those that affect protective reflexes (like cough and swallowing) due to direct or indirect mechanisms, and drugs that facilitate gastric dysbiosis or affect esophageal and intestinal motility. Chief among the first group are benzodiazepines and antipsychotics, while proton pump inhibitors are the most well-studied in the latter group. Pill esophagitis may also exacerbate swallowing dysfunction. On the other hand, some research has also focused on pharmaceutical modulation of the risk of aspiration pneumonia. Angiotensin-converting enzyme inhibitors have been demonstrated to be associated with a decrease in the hazard of aspiration pneumonia in high-risk patients of Chinese or Japanese origin. Drugs like amantadine, nicergoline, or folic acid have shown some promising results in stroke patients, although the available evidence is thus far not enough to allow for any meaningful conclusions. Importantly, antimicrobial prophylaxis has been proven to be ineffective. Focusing on modifiable risk factors for aspiration pneumonia is relevant since this may help to reduce the incidence of this often severe problem. Among these, several commonly used drug classes have been shown to increase the risk of aspiration pneumonia. These drugs should be withheld in the high-risk population whenever possible, alongside general measures, such as the semirecumbent position during sleep and feeding.

Incidence and Predictors of Aspiration Pneumonia Among Stroke Patients in Western Amhara Region, North-West Ethiopia: A Retrospective Follow Up Study

Background

Aspiration pneumonia is one of the major complications among hospitalized stroke patients, with global incidence ranging from 5-83% and hospital mortality rate of up to 70%. This study aimed to assess the incidence and identify predictors of aspiration pneumonia among stroke patients in Western Amhara region, North-West Ethiopia.

Methods

An institution-based retrospective follow-up study was conducted on a simple random sample of 568 stroke patients in Western Amhara region admitted at Felege Hiwot Referral Hospital. Log binomial regression model, a generalized linear model with log link, was applied to identify significant predictors of aspiration pneumonia.

Results

Cumulative incidence of aspiration pneumonia among the 568 sampled patients was 23.06%. Males were 1.71 times more at risk to acquire aspiration pneumonia than females (ARR = 1.71, 95% CI 1.07-2.74). Patients with vomiting and dysphagia were at more risk of acquiring aspiration pneumonia as compared with patients without vomiting and dysphagia (ARR = 1.81, 95% CI 1.04-3.14 and ARR = 1.95, 95% CI 1.10-3.48, respectively). Patients who received antibiotic prophylaxis and patients with Glasgow Coma Scale greater than 12 had less risk of acquiring aspiration pneumonia as compared with those who did not receive antibiotic prophylaxis and patients with Glasgow Coma Scale less than 8 (ARR = 0.10, 95% CI 0.04-0.28 and ARR = 0.45, 95% CI 0.22-0.94, respectively).

Conclusion

The cumulative incidence of aspiration pneumonia among sampled patients was 23.06%. Vomiting, dysphagia, antibiotic treatment and Glasgow Coma Scale showed significant correlation with the acquiring of aspiration pneumonia. Therefore, we recommend health-care providers should give special attention for patients with these risk factors to prevent aspiration pneumonia.

Post-Stroke Pneumonia in Real-World Practice: Background, Microbiological Examination, and Treatment

Post-stroke pneumonia (PSP) has an impact on acute ischemic stroke (AIS). Although predictive scores for PSP have been developed, it is occasionally difficult to predict. Clarifying how PSP was treated after its onset in clinical practice is important. Admitted patients with AIS over a 2-year period were retrospectively reviewed. Of 281 patients with AIS, 24 (8.5%) developed PSP. The integer-based pneumonia risk score was higher in patients with PSP. The onset of PSP was frequently seen up to the 4th day of hospitalization. Of patients with PSP, sputum examination yielded Geckler 4 or 5 in only 8.3%. Angiotensin-converting enzyme inhibitor (ACE-I) was more frequently administered to patients with PSP; however, all these cases were started with ACE-I following PSP onset. Nasogastric tubes (NGTs) were inserted in 16 of the patients with PSP, of whom 11 were inserted following PSP onset. Multivariate analysis showed that PSP onset was a poor prognostic factor independent of the female sex, urinary tract infection, and National Institutes of Health Stroke Scale. PSP treatment would benefit from the administration of antimicrobials and ACE-I, as well as NGT insertion. To select effective agents for PSP and evaluate the indications for NGT insertion, further case studies are needed.

Angiotensin-converting enzyme inhibitors reduce community-acquired pneumonia hospitalization and mortality

BACKGROUND

Pneumonia is a global disorder and a common reason for prolonged hospitalization. Angiotensin-converting enzyme inhibitors (ACEi) have pleiotropic effects that support a role in modulating pneumonia, but results have been controversial.

OBJECTIVES

The present study was conducted to elucidate an ACEi-induced pneumonia benefit in at-risk neurologically impaired population and to determine whether a mortality benefit exists.

METHODS

A cohort study using a large health-system of 29,011 unique ACEi users and 1635 case patients 65 years of age or older without neurological disorders affecting swallowing who were admitted with community-acquired pneumonia hospitalization and followed up from January 1, 2015 to December 31, 2019 (5 years). The association between ACEi use and pneumonia hospitalization and mortality were determined after propensity score matching using Cox and logistic regression.

RESULTS

The experimental cohort was 74.9 ± 7.3 years and 51% were male. ACEi users had lower odds of acquiring pneumonia versus ACEi non-users (odds ratio) 0.72 [95% Confidence Interval (CI) 0.51 to 0.99]; p = 0.048. The risk of short-term mortality (<30 days) (HR) 0.42, p < 0.001 and long-term mortality (≥30 day) (HR) 0.83, p < 0.002 was significantly lower for ACEi users compared with the ACEi non-users.

CONCLUSIONS

ACEi use in patients at risk of pneumonia without neurological swallowing disorders is associated with reduction in hospitalization and lowering of short- and long-term mortality. Given the high incidence of morbidity and mortality associated with pneumonia, and the susceptibility in older populations with underlying cardiovascular or renal disease or social dependencies, our data support the prescribing of ACEi in these populations to reduce pneumonia hospitalization risk as well as short- and long-term mortality.

A Comparative Study on the Effect of Acute Pharyngeal Stimulation with TRP Agonists on the Biomechanics and Neurophysiology of Swallow Response in Patients with Oropharyngeal Dysphagia

Fluid thickening is the main compensatory strategy for patients with oropharyngeal dysphagia (OD) associated with aging or neurological diseases, and there is still no pharmacological treatment. We aimed to compare the effects of increasing bolus viscosity with that of acute stimulation with TRPV1, TRPA1 or TRPM8 agonists on the biomechanics and neurophysiology of swallow response in patients with OD. We retrospectively analyzed seven studies from our laboratory on 329 patients with OD. The effect of increasing shear viscosity up to 3682 mPa·s was compared by videofluoroscopy and pharyngeal sensory evoked potentials (pSEP) with that of adding to the bolus: capsaicin (TRPV1, 150 μM/10 μM), piperine (TRPA1/V1, 1 mM/150 μM), menthol (TRPM8, 1 mM/10 mM), cinnamaldehyde-zinc (TRPA1, 100 ppm−70 mM), citral (TRPA1, 250 ppm) or citral-isopulegol (TRPA1-TRPM8, 250 ppm−200 ppm). Fluid thickening improved the safety of swallow by 80% (p < 0.0001) by delaying bolus velocity by 20.7 ± 7.0% and time to laryngeal vestibule closure (LVC) by 23.1 ± 3.7%. Capsaicin 150μM or piperine 1 mM significantly improved safety of swallow by 50% (p < 0.01) and 57.1% (p < 0.01) by speeding time to LVC by 27.6% (p < 0.001) and 19.5% (p < 0.01) and bolus velocity by 24.8% (p < 0.01) and 16.9% (p < 0.05), respectively. Cinnamaldehyde-zinc shortened the P2 latency of pSEPs by 11.0% (p < 0.01) and reduced N2-P2 amplitude by 35% (p < 0.01). In conclusion, TRPV1 and TRPV1/A1 agonists are optimal candidates to develop new pharmacological strategies to promote the recovery of brain and swallow function in patients with chronic OD.

The Association Between Antihypertensive Drug Use and Hospitalization for Pneumonia in the General Population: A Case-Crossover Study Using the National Health Insurance Database of Korea

BACKGROUND

Previous studies have reported an association between pneumonia risk and the use of certain drugs. We investigated the relationship between antihypertensive drugs and pneumonia in the general population.

METHODS

This case-crossover study utilized the nationwide data of South Korea. We included participants who were hospitalized for pneumonia. A single case period was defined as 30 days before pneumonia onset, and two control periods were established (90-120 and 150-180 days before pneumonia onset). Further, we performed sensitivity and subgroup analyses (according to the presence of diabetes, documented disability, and whether participants were aged ≥ 70 years). We used conditional logistic regression models adjusted for covariates, such as angiotensin-converting-enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), other antihypertensives, statins, antipsychotics, benzodiazepine, and the number of outpatient visits.

RESULTS

In total, 15,463 subjects were included in this study. ACE inhibitors (adjusted odds ratio [aOR], 0.660; 95% confidence interval [CI], 0.558-0.781), ARBs (aOR, 0.702; 95% CI, 0.640-0.770), and other antihypertensive drugs (aOR, 0.737; 95% CI, 0.665-0.816) were significantly associated with reduced pneumonia risk. Subgroup analyses according to the presence of diabetes mellitus, documented disability, and whether participants were aged ≥ 70 years consistently showed the association of antihypertensives with a reduced risk of hospitalization for pneumonia.

CONCLUSION

All antihypertensive drug types were related to a lower risk of hospitalization for pneumonia in the general population. Our results implied that frequent medical service usage and protective immunity were primarily related to a reduced risk of pneumonia in the general population of South Korea.

Factors associated with gravity-dependent distribution on chest CT in elderly patients with community-acquired pneumonia: a retrospective observational study

Although lung involvement in aspiration pneumonia typically has a gravity-dependent distribution on chest images, which patient’s conditions contribute to its radiological pattern has not been fully elucidated. This study was designed to determine the factors associated with the gravity-dependent distribution of community-acquired pneumonia (CAP) on chest computed tomography (CT). This retrospective study included elderly patients aged ≥ 65 years with CAP who underwent chest CT within 1 week before or after admission. The factors associated with lower lobe- and posterior-predominant distributions of ground glass opacity or airspace consolidation were determined. Of the 369 patients with CAP, 348 (94%) underwent chest CT. Multivariate analyses showed that impaired consciousness, a low Barthel index of activities of daily living, and high hemoglobin levels were associated with lower lobe-predominant distribution, while male sex and impaired consciousness were associated with posterior-predominant distribution. Cerebrovascular diseases were unrelated to these distributions. While male sex, impaired consciousness, high hemoglobin levels, low albumin levels, and the number of involved lobes were associated with in-hospital mortality, gravity-dependent distributions were not. Impaired consciousness might be the most significant predictor of aspiration pneumonia; however, the gravity-dependent distribution of this disease is unlikely to affect disease prognosis.

Therapeutic applications of capsaicin in humans to target conditions of the respiratory system: A scoping review

BACKGROUND

Various studies have explored potential therapeutic applications of capsaicin in human medicine, for example in pain, obesity, cancer, cardiovascular and respiratory disease. The aim of this scoping review was to identify and chart available evidence on therapeutic applications of capsaicin in humans using any mode of capsaicin delivery to treat conditions of the respiratory system.

METHODS

Electronic bibliographic databases (Web of Science, PubMed, Medline, ScienceDirect, Embase, Scopus) were searched from inception to 2021 to identify experimental studies reporting clinical outcomes of therapeutic applications of capsaicin. Studies with or without control group published in peer-reviewed journals were included. Animal studies, studies of human cell lines, and physiological proof of concept studies were excluded. Reviewer pairs independently double-screened 2799 search results for inclusion.

RESULTS

Twenty-three original studies were included. Capsaicin has been investigated for the treatment of non-allergic rhinitis (n = 15), nasal polyposis (n = 3), allergic rhinitis (n = 2), unexplained chronic cough (n = 2), and prevention of aspiration pneumonia (n = 1). Modes of delivery included intranasal application (nasal spray, soaked pads, solution), inhalation, ingestion, and aural ointment. Seventeen studies reported positive effects of capsaicin on clinical outcomes for rhinitis, nasal polyposis, chronic cough, and pneumonia. Sixteen studies reported on the safety of capsaicin, with no reports of significant adverse events and overall fair to good patient acceptability.

CONCLUSION

While the evidence identified in this review has limited implications for clinical practice, studies support the general safety of capsaicin as administered in these studies and highlight emerging strands of research and clinical hypotheses which warrant further examination.

Effect of long-term clarithromycin therapy on prevention of pneumonia in older adults: A randomized, controlled trial

AIM

Pneumonia in older adults is increasingly recognized as a healthcare issue in countries with an aging population. Long-term macrolide therapy reduces exacerbations of chronic respiratory diseases, but its effects on the prevention of pneumonia have not been determined.

METHODS

We carried out a randomized, controlled trial to test the effect of long-term clarithromycin therapy on the prevention of pneumonia among older adults. People aged ≥65 years who had recovered from pneumonia within the previous 3 months were recruited and randomly allocated to a long-term, low-dose clarithromycin (CAM) therapy group (n = 13) or a control group (n = 15).

RESULTS

Both groups were followed up until recurrence of pneumonia. The median follow-up period was 251 days (95% CI 171-330) in the CAM group and 132 days (95% CI 67-196) in the control group (P = 0.627). The recurrence rate of pneumonia was two out of 13 (15%) in the CAM group and five out of 15 (33%) in the control group (P = 0.268). The median time to recurrence of pneumonia was 315 days (95% CI 249-382) in the CAM group and 260 days (95% CI 184-335) in the control group (P = 0.260). None of the differences between groups were statistically significant.

CONCLUSIONS

No statistically significant suppressive effects of long-term, low-dose macrolide therapy on the development of pneumonia among older people were found in this small sample. A large-scale, randomized, controlled study is required. Geriatr Gerontol Int 2019; 19: 1006-1009.

Aspiration pneumonia induces muscle atrophy in the respiratory, skeletal, and swallowing systems

BACKGROUND

Repetition of the onset of aspiration pneumonia in aged patients is common and causes chronic inflammation. The inflammation induces proinflammatory cytokine production and atrophy in the muscles. The proinflammatory cytokines induce muscle proteolysis by activating calpains and caspase-3, followed by further degradation by the ubiquitin-proteasome system. Autophagy is another pathway of muscle atrophy. However, little is known about the relationship between aspiration pneumonia and muscle. For swallowing muscles, it is not clear whether they produce cytokines. The main objective of this study was to determine whether aspiration pneumonia induces muscle atrophy in the respiratory (the diaphragm), skeletal (the tibialis anterior, TA), and swallowing (the tongue) systems, and their possible mechanisms.

METHODS

We employed a mouse aspiration pneumonia model and computed tomography (CT) scans of aged pneumonia patients. To induce aspiration pneumonia, mice were inoculated with low dose pepsin and lipopolysaccharide solution intra-nasally 5 days a week. The diaphragm, TA, and tongue were isolated, and total RNA, proteins, and frozen sections were stored. Quantitative real-time polymerase chain reaction determined the expression levels of proinflammatory cytokines, muscle E3 ubiquitin ligases, and autophagy related genes. Western blot analysis determined the activation of the muscle proteolysis pathway. Frozen sections determined the presence of muscle atrophy. CT scans were used to evaluate the muscle atrophy in aged aspiration pneumonia patients.

RESULTS

The aspiration challenge enhanced the expression levels of proinflammatory cytokines in the diaphragm, TA, and tongue. Among muscle proteolysis pathways, the aspiration challenge activated caspase-3 in all the three muscles examined, whereas calpains were activated in the diaphragm and the TA but not in the tongue. Activation of the ubiquitin-proteasome system was detected in all the three muscles examined. The aspiration challenge activated autophagy in the TA and the tongue, whereas weak or little activation was detected in the diaphragm. The aspiration challenge resulted in a greater proportion of smaller myofibers than in controls in the diaphragm, TA, and tongue, suggesting muscle atrophy. CT scans clearly showed that aspiration pneumonia was followed by muscle atrophy in aged patients.

CONCLUSIONS

Aspiration pneumonia induced muscle atrophy in the respiratory, skeletal, and swallowing systems in a preclinical animal model and in human patients. Diaphragmatic atrophy may weaken the force of cough to expectorate sputum or mis-swallowed contents. Skeletal muscle atrophy may cause secondary sarcopenia. The atrophy of swallowing muscles may weaken the swallowing function. Thus, muscle atrophy could become a new therapeutic target of aspiration pneumonia.

Supportive effect of interferential current stimulation on susceptibility of swallowing in guinea pigs

Sensory-motor control of the pharyngeal swallow requires sensory afferent inputs from the pharynx and larynx evoked by introducing bolus into the pharynx. Patients with reduced sensitivity of the pharynx and larynx are likely to have a swallowing impairment, such as pre-swallow aspiration due to delayed swallow triggering. Interferential current stimulation applied to the neck is thought to improve the swallowing function of dysphagic patients, although the mechanism underlying the facilitatory effect of such stimulation remains unknown. In the present study, we examined the changes in the elicitability of swallowing due to the stimulation and the responses of the swallowing-related neurons in the nucleus tractus solitarius and in the area adjacent to the stimulation in decerebrate and paralyzed guinea pigs. The swallowing delay time was shortened by the stimulation, whereas the facilitatory effect of eliciting swallowing was attenuated by kainic acid injection into the nucleus tractus solitarius. Approximately half of the swallowing-related neurons responded to the stimulation. These data suggest that the interferential current stimulation applied to the neck could enhance the sensory afferent pathway of the pharynx and larynx, subserving excitatory inputs to the neurons of the swallowing pattern generator, thereby facilitating the swallowing reflex.

Use of proton pump inhibitors is associated with increased mortality due to nosocomial pneumonia in bedridden patients receiving tube feeding

AIM

To investigate the association between the use of proton pump inhibitors (PPI) and nosocomial pneumonia and gastrointestinal bleeding in bedridden patients receiving tube feeding.

METHODS

A total of 116 bedridden hospitalized patients receiving tube feeding, of which 80 were supported by percutaneous endoscopic gastrostomy and 36 by nasogastric tube, were included in the present study. The patients were divided into two groups: 62 patients treated with PPI (PPI group) and 54 patients without PPI (non-PPI group). Mortality due to nosocomial pneumonia was evaluated using the Kaplan-Meier approach and the log-rank test.

RESULTS

A total of 36 patients (31%) died of nosocomial pneumonia during the observation period; the mortality rate due to nosocomial pneumonia was significantly higher in the PPI group than in the non-PPI group (P = 0.0395). Cox proportional hazard analysis showed that the use of PPI and lower levels of serum albumin were independent predictors of 2-year mortality due to nosocomial pneumonia. Gastrointestinal bleeding was observed in four patients in the non-PPI group (7.7%) and in one patient in the PPI group (1.6%); there was no significant difference between the two groups.

CONCLUSION

The use of PPI in bedridden tube-fed patients was independently associated with mortality due to nosocomial pneumonia, and the PPI group had a non-significant lower incidence of gastrointestinal bleeding than the non-PPI group. Geriatr Gerontol Int 2018; 18: 1215-1218.

Cilostazol for the prevention of pneumonia: a systematic review

Background

Pneumonia is a very common disease, especially among the elderly. Various drugs’ preventive effects against pneumonia have been reported. The antiplatelet drug cilostazol is used to prevent pneumonia, but the robustness of its efficacy is unclear. This review estimates the effectiveness of cilostazol for preventing pneumonia in elderly individuals.

Methods

The following databases were searched from the earliest record to January 2016, without language restriction (the secondary search was conducted on February 2017): MEDLINE, Cochrane Library, CINAHL, and Ichushi-Web. Studies were included if they were published randomized controlled trials investigating the preventive effect of cilostazol on pneumonia in the elderly. The outcome was the incidence of pneumonia.

Results

Two trials were identified that met the search criteria (1423 participants). Both trials compared cilostazol with no antiplatelet in patients with a history of cerebral infarction. A meta-analysis was not performed because of the small number of trials and the heterogeneity of the data. Both trials suggested that cilostazol reduced the incidence of pneumonia (risk ratio [RR] 0.40; 95% confidence interval [CI] 0.22–0.73 in one trial, RR 0.20; 95% CI 0.06–0.69 in the other) and the recurrence of cerebral infarction (0.43; 0.21–0.90, 0.53; 0.34–0.81, respectively). The quality of evidence provided by the trials was very low, mainly because of the high risk of bias.

Conclusions

It is difficult to draw conclusions on the basis of two trials. Moreover, in the two trials, cilostazol could have reduced the incidence of pneumonia via a reduction of the recurrence of cerebral infarction, which suggests that other antiplatelets could also have the same effects. Stronger evidence is required from large trials assessing the effectiveness of cilostazol for the prevention of pneumonia.

Trial registration

PROSPERO (CRD42016036724).

Electronic supplementary material

The online version of this article (10.1186/s41479-018-0046-5) contains supplementary material, which is available to authorized users.

Screening Tool for Older Persons' Appropriate Prescriptions for Japanese: Report of the Japan Geriatrics Society Working Group on "Guidelines for medical treatment and its safety in the elderly"

AIM

In 2005, the Japan Geriatrics Society published a list of potentially inappropriate medication that was an extract from the "Guidelines for medical treatment and its safety in the elderly 2005." The 2005 guidelines are due for a revision, and a new comprehensive list of potentially inappropriate medications is required.

METHODS

A total of 15 diseases, conditions and special areas related to their clinical care were selected. We originated clinical questions and keywords for these 15 areas, carried out a systematic review using these search criteria, and formulated guidelines applying the Grading of Recommendations Assessment, Development and Evaluation system advocated by Minds2014. If we did not find good evidence despite the drug being clinically important, we looked for evidence of efficacy and for disease-specific guidelines, and incorporated them into our guidelines.

RESULTS

We selected 2098 articles (140 articles per area), and extracted another 186 articles through a manual search. We further added guidelines based on disease entity and made two lists, one of "drugs to be prescribed with special caution" and the other of "drugs to consider starting," primarily considering individuals aged 75 years or older or those who are frail or in need of special care.

CONCLUSIONS

New lists of potentially inappropriate medications and potential prescribing omissions called "Screening Tool for Older Person's Appropriate Prescriptions for Japanese" were constructed. We anticipate that future studies will highlight more evidence regarding the safety of high-quality drugs, further improving the provision of appropriate medical care for the elderly. Geriatr Gerontol Int 2016: 16: 983-1001.

Prognostic implications of aspiration pneumonia in patients with community acquired pneumonia: A systematic review with meta-analysis

Aspiration pneumonia is thought to be associated with a poor outcome in patients with community acquired pneumonia (CAP). However, there has been no systematic review regarding the impact of aspiration pneumonia on the outcomes in patients with CAP. This review was conducted using the MOOSE guidelines: Patients: patients defined CAP. Exposure: aspiration pneumonia defined as pneumonia in patients who have aspiration risk. Comparison: confirmed pneumonia in patients who were not considered to be at high risk for oral aspiration. Outcomes: mortality, hospital readmission or recurrent pneumonia. Three investigators independently identified published cohort studies from PubMed, CENTRAL database, and EMBASE. Nineteen studies were included for this systematic review. Aspiration pneumonia increased in-hospital mortality (relative risk, 3.62; 95% CI, 2.65–4.96; P < 0.001, seven studies) and 30-day mortality (3.57; 2.18–5.86; P < 0.001, five studies). In contrast, aspiration pneumonia was associated with decreased ICU mortality (relative risk, 0.40; 95% CI, 0.26–0.60; P < 0.00001, four studies). Although there are insufficient data to perform a meta-analysis on long-term mortality, recurrent pneumonia, and hospital readmission, the few reported studies suggest that aspiration pneumonia is also associated with these poor outcomes. In conclusion, aspiration pneumonia was associated with both higher in-hospital and 30-day mortality in patients with CAP outside ICU settings.

Chronic inflammation, lymphangiogenesis, and effect of an anti-VEGFR therapy in a mouse model and in human patients with aspiration pneumonia

Chronic inflammation induces lymphangiogenesis and blood vessel remodelling. Since aged pneumonia patients often have repeated episodes of aspiration pneumonia, the pathogenesis may involve chronic inflammation. For lymphangiogenesis, VEGFR-3 and its ligand VEGF-C are key factors. No previous studies have examined chronic inflammation or vascular changes in aspiration pneumonia or its mouse models. In lung inflammation, little is known about the effect of blocking VEGFR-3 on lung lymphangiogenesis and, moreover, its effect on the disease condition. This study aimed to establish a mouse model of aspiration pneumonia, examine the presence of chronic inflammation and vascular changes in the model and in patients, and evaluate the effect of inhibiting VEGFR-3 on the lymphangiogenesis and disease condition in this model. To induce aspiration pneumonia, we repeated inoculation of pepsin at low pH and LPS into mice for 21-28 days, durations in which bronchioalveolar lavage and plasma leakage in the lung suggested the presence of exaggerated inflammation. Conventional and immunohistochemical analysis of tracheal whole mounts suggested the presence of chronic inflammation, lymphangiogenesis, and blood vessel remodelling in the model. Quantitative RT-PCR of the trachea and lung suggested the involvement of lymphangiogenic factor VEGF-C, VEGFR-3, and pro-inflammatory cytokines. In the lung, the aspiration model showed the presence of chronic inflammation and exaggerated lymphangiogenesis. Treatment with the VEGFR inhibitor axitinib or the VEGFR-3 specific inhibitor SAR131675 impaired lymphangiogenesis in the lung and improved oxygen saturation in the aspiration model. Since the lung is the main site of aspiration pneumonia, the changes were intensive in the lung and mild in the trachea. Human lung samples also showed the presence of chronic inflammation and exaggerated lymphangiogenesis, suggesting the relevance of the model to the disease. These results suggest lymphatics in the lung as a new target of analysis and therapy in aspiration pneumonia.

Perindopril increases the swallowing reflex by inhibiting substance P degradation and tyrosine hydroxylase activation in a rat model of dysphagia

Patients with hypertension have a high risk of ischemic stroke and subsequent stroke-associated pneumonia. Stroke-associated pneumonia is most likely to develop in patients with dysphagia. The present study was designed to compare the ameliorative effects of different treatments in rat model of dysphagia. Spontaneously hypertensive rats were treated with bilateral common carotid artery occlusion (BCAO) to induce chronic cerebral hypoperfusion causing disorders of the swallowing reflex. Angiotensin-converting enzyme (ACE) inhibitors (perindopril, imidapril and enalapril), an angiotensin II type 1-receptor blocker (losartan), a vasodilator (hydralazine) and an indirect dopamine agonist (amantadine) were dissolved in drinking water and administered to the rats for six weeks. The blood pressure, the swallowing reflex under anesthesia, the substance P content in the striatum and the tyrosine hydroxylase (TH) expression in the substantial nigra were measured. Compared to the vehicle control, the decrease in the swallowing reflex induced by BCAO was attenuated significantly by enalapril, imidapril and perindopril, but only slightly by losartan. Hydralazine had no effect on the swallowing reflex. Amantadine significantly attenuated the decreased swallowing reflex but increased the blood pressure. Cerebral hypoperfusion for six weeks decreased the TH expression and substance P level. Perindopril improved both the TH expressions and substance P level, but imidapril, enalapril and amantadine only improved the substance P level. The present findings indicate that perindopril could be useful for preventing dysphagia in the chronic stage of stroke by attenuating the decrease in TH expression and the decrease in the substance P level.

Evidence-Based Measures for Preventing Aspiration Pneumonia in Patients with Dysphagia

Dysphagia increases the risk of aspiration pneumonia with resultant morbidity and recurrent hospital admissions. With a rapidly ageing population and an increasing complex chronic disease burden, the prevalence of patients with dysphagia will increase. Family physicians will encounter more patients with dysphagia in various practice settings of primary, intermediate long term care and tertiary settings. We conducted a comprehensive literature review on the latest established evidence on measures to prevent aspiration pneumonia in patients with dysphagia. We found that many studies involved only small numbers of patients and lacked the methodological quality of well-conducted randomised contolled trials. Interventions that showed strongest evidence in preventing aspiration pneumonia were good oral health and the use of Angiotensin Converting Enzyme (ACE) inhibitor. We have provided a summary of key recommendations for family physicians, based on the Scottish Intercollegiate Guidelines Network (SIGN) framework in order to reflect the latest evidence-based strategies on measures to prevent aspiration pneumonia in patients with dysphagia.

Serum creatinine and albumin decline predict the contraction of nosocomial aspiration pneumonia in patients undergoing hemodialysis

Aspiration pneumonia (AP) is prevalent in older adults and the hemodialysis (HD) population has been getting older. Therefore, it is speculated that increasing number of HD patients would suffer from AP. However, the clinical aspects of AP in HD patients have not been elucidated. Consecutive HD patients with nosocomial AP hospitalized in our university hospital from April 2007 to December 2008 were recruited. Their clinical characteristics, risk factors for contraction, and the fatality of AP and treatment options were described. Nineteen out of 356 hospitalized HD patients had AP and 8 out of 19 AP patients died, indicating the incidence rate and fatality rate were 5.34% and 42.1%, respectively. Multiple regression analysis revealed that the risk factors for contracting AP included age, body mass index, serum creatinine levels (Cre) and the monthly decline rate of Cre. It also revealed that serum albumin (Alb) and basal total cholesterol levels, the decline rate of Alb and Cre levels, and the duration of AP were independent risk factors for fatality. Survivors were most often treated with tube feeding. Both contraction rate and fatality of nosocomial AP were high among HD patients. Both the malnutrition as well as the decline rate for nutrition and muscle volume indicated by falls in Alb and Cre, respectively, had clinical relevance in AP. Maintaining nutritional state by tube feeding and muscle volume seems to be the mainstay for the prevention and the treatment of AP in HD patients.

Risk of pneumonia associated with use of angiotensin converting enzyme inhibitors and angiotensin receptor blockers: systematic review and meta-analysis

OBJECTIVE

To systematically review longitudinal studies evaluating use of angiotensin converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) and risk of pneumonia.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Medline through PubMed, Web of Science with conference proceedings (inception to June 2011), and US Food and Drug Administration website (June 2011). Systematic reviews and references of retrieved articles were also searched.

STUDY SELECTION

Two reviewers independently selected randomised controlled trials and cohort and case-control studies evaluating the use of ACE inhibitors or ARBs and risk of pneumonia and retrieved characteristics of the studies and data estimates.

DATA SYNTHESIS

The primary outcome was incidence of pneumonia and the secondary outcome was pneumonia related mortality. Subgroup analyses were carried according to baseline morbidities (stroke, heart failure, and chronic kidney disease) and patients' characteristics (Asian and non-Asian). Pooled estimates of odds ratios and 95% confidence intervals were derived by random effects meta-analysis. Adjusted frequentist indirect comparisons between ACE inhibitors and ARBs were estimated and combined with direct evidence whenever available. Heterogeneity was assessed using the I(2) test.

RESULTS

37 eligible studies were included. ACE inhibitors were associated with a significantly reduced risk of pneumonia compared with control treatment (19 studies: odds ratio 0.66, 95% confidence interval 0.55 to 0.80; I(2) = 79%) and ARBs (combined direct and indirect odds ratio estimate 0.69, 0.56 to 0.85). In patients with stroke, the risk of pneumonia was also lower in those treated with ACE inhibitors compared with control treatment (odds ratio 0.46, 0.34 to 0.62) and ARBs (0.42, 0.22 to 0.80). ACE inhibitors were associated with a significantly reduced risk of pneumonia among Asian patients (0.43, 0.34 to 0.54) compared with non-Asian patients (0.82, 0.67 to 1.00; P<0.001). Compared with control treatments, both ACE inhibitors (seven studies: odds ratio 0.73, 0.58 to 0.92; I(2)=51%) and ARBs (one randomised controlled trial: 0.63, 0.40 to 1.00) were associated with a decrease in pneumonia related mortality, without differences between interventions.

CONCLUSIONS

The best evidence available points towards a putative protective role of ACE inhibitors but not ARBs in risk of pneumonia. Patient populations that may benefit most are those with previous stroke and Asian patients. ACE inhibitors were also associated with a decrease in pneumonia related mortality, but the data lacked strength.

Nicergoline improves dysphagia by upregulating substance P in the elderly

Dysphagia induces silent aspiration, which is a known risk factor for aspiration pneumonia in the elderly. Dysphagia is associated with impaired substance P secretion. Because nicergoline was recently reported to enhance substance P secretion, it may improve dysphagia by upregulating substance P; however, roles for nicergoline in this process have not been demonstrated. We therefore compared the effects of nicergoline on serum substance P and dysphagia with the effects of imidapril, an angiotensin-converting enzyme (ACE) inhibitor whose efficacy in improving dysphagia and preventing pneumonia has been previously demonstrated.We randomly assigned 60 elderly patients with both dysphagia and a previous history of pneumonia to receive either imidapril (5 mg/d; n = 30) or nicergoline (15 mg/d; n = 30) for 6 months. Primary outcomes were the effects of these drugs on the substance P level and dysphagia 4 weeks after the start of treatment. Secondary outcome was the effect of these drugs on pneumonia recurrence during the 6 months of treatment.Significant elevations of serum substance P were obtained by both medications after 4 weeks of treatment. Patients whose dysphagia was improved showed significantly increased serum levels of substance P. There was no statistically significant difference in the overall proportion of patients who showed improvements in dysphagia and pneumonia recurrence with imidapril or nicergoline treatment. Nicergoline, but not imidapril, seemed to be more effective at improving dysphagia and elevating serum substance P in patients with dementia.In conclusion, nicergoline has a comparable effect to ACE inhibitors for improving dysphagia. Nicergoline might be a novel regimen for the treatment of dysphagia in the elderly who are not treatable with ACE inhibitors.

Pneumonia and influenza – specific considerations in care homes

This review provides an update on current evidence surrounding epidemiology, treatment and prevention of lower respiratory tract infection, with special reference to pneumonia and influenza, in care home residents. The care home sector is growing and provides a unique ecological niche for infections, housing frail older people with multiple co-morbidities and frequent contact with healthcare services. There are therefore considerations in the epidemiology and management of these conditions that are specific to care homes. Opportunities for prevention, in the form of vaccination strategies and improving oral hygiene, may reduce the burden of these diseases in the future. Work is needed to research these infections specifically in the care home setting, and this article highlights current gaps in our knowledge.

[Oropharyngeal dysphagia and aspiration]

Oropharyngeal dysphagia, or inability to swallow liquids and/or solids, is one of the less well known geriatric syndromes, despite its enormous impact on functional ability, quality of life and health in affected individuals. The origin of oropharyngeal dysphagia can be structural or functional. Patients with neurodegenerative or cerebrovascular diseases and the frail elderly are the most vulnerable. The complications of oropharyngeal dysphagia are malnutrition, dehydration and aspiration, all of which are serious and provoke high morbidity and mortality. Oropharyngeal aspiration causes frequent respiratory infections and aspiration pneumonias. Antibiotic therapy must cover the usual microorganisms of the oropharyngeal flora. Oropharyngeal dysphagia should be identified early in risk groups through the use of screening methods involving clinical examination of swallowing and diagnostic confirmation methods. The simplest and most effective therapeutic intervention is adaptation of the texture of the solid and the viscosity of the liquid.

Can continuous pump feeding reduce the incidence of pneumonia in nasogastric tube-fed patients? A randomized controlled trial

BACKGROUND & AIMS

Continuous pump feeding is often used to reduce aspiration risk in older patients on tube feeding, but its effectiveness in preventing aspiration pneumonia is unproven. A randomized controlled trial was therefore performed to examine the effectiveness of continuous pump feeding in decreasing the incidence of pneumonia in tube-fed older hospital patients.

METHODS

One hundred and seventy eight elderly patients from three convalescence hospitals and one infirmary, on nasogastric tube feeding, were randomly assigned to have intermittent bolus (bolus) or continuous pump (pump) feeding for 4weeks. The primary outcome was the incidence of pneumonia. The secondary outcome was mortality.

RESULTS

Eighty five subjects were randomized into the pump group and 93 in the bolus group. The groups were comparable in age, nutritional and functional status, co-morbidities and history of pneumonia, except that there were more women in the pump group. Within 4weeks, 15 subjects (17.6%) in the pump group and 18 (19.4%) in the bolus group developed pneumonia. Seven subjects (8.2%) in pump group and 13 subjects (14.0%) in bolus group died. There was no significant difference in either pneumonia or death rates between the two groups.

CONCLUSION

Continuous pump feeding did not significantly affect the rates of pneumonia or mortality in tube-fed older hospital patients when compared with intermittent bolus feeding.