Pulmonary aspiration of gastric contents

Association of early antibiotic therapy and in-hospital mortality in adult mild-to-moderate acute aspiration pneumonitis: a cohort study

BACKGROUND

Patients with aspiration pneumonitis often receive empiric antibiotic therapy despite it being due to a non-infectious, inflammatory response.

OBJECTIVE

To study the benefits of early antibiotic therapy in patients with suspected aspiration pneumonitis in an acute care hospital.

DESIGN

Retrospective cohort study using electronic medical records from Teine Keijinkai Hospital.

PARTICIPANTS

Adults aged over 18 years admitted with a diagnosis of aspiration pneumonitis to the Department of General Internal Medicine or Emergency Department between January 1, 2008, and May 31, 2019. A diagnosis of aspiration pneumonitis was defined as a documented macro-aspiration event and a chest radiograph demonstrating new radiographic infiltrates.

MAIN MEASURES

Patients were classified into the "early antibiotic treatment" group and the "no or late treatment" group depending on whether they received antibiotic therapy for respiratory bacterial pathogens within 8 h of arrival. The primary outcome was in-hospital all-cause mortality. Secondary outcomes included length of hospital stay, antibiotic-free days, duration of fever, readmission within one month, and incidence of complications.

KEY RESULTS

Of the 146 patients enrolled, 52 (35.6%) did not receive early antibiotic therapy, while the remaining 94 (64.4%) did. There was no difference in in-hospital mortality rates between the groups after adjustment for potential confounding variables using Cox proportional hazards analysis (hazard ratio 2.78; 95% confidence interval, 0.57-13.50, p = 0.20). Patients in the no or late treatment group had more antibiotic-free days (p < 0.001) and a shorter length of hospital stay among survivors (p = 0.040) than did those in the early antibiotic treatment group. There were no statistically significant differences between the groups with respect to other secondary outcomes.

CONCLUSIONS

Early antibiotic therapy for acute aspiration pneumonitis was not associated with in-hospital mortality, but was associated with a longer hospital stay and prolonged use of antibiotics.

An Esophagogram or Tracheobronchogram? A Review of Barium Sulfate Aspiration

The barium swallow is an important radiological investigation used for the diagnosis of upper gastrointestinal anatomical disorders like esophageal cancer, diverticulum, achalasia, foreign body, among others. Generally, it is believed to be a safe technique with rare complications, but few cases of barium sulfate aspiration have been reported in the literature with multiple complications. We are reporting a case of an elderly male who underwent esophagogram for the workup of chronic dysphagia, aspirated barium sulfate, and went into respiratory failure and circulatory shock several hours later. Moreover, we also did a systematic literature search and reviewed all available articles on aspiration of barium sulfate and its potential complications. We focused on predisposing factors for aspiration, clinical presentation, complications after aspiration, and prognosis with the aim to better understand and manage this condition.

Incidence of Pneumonia After Videofluoroscopic Swallowing Study and Associated Factors

Pneumonia after videofluoroscopic swallow study (VFSS) is sometimes considered to be caused by aspiration during VFSS; however, to our knowledge, a relationship between these events has not been clearly investigated. The aim of this study was to assess the incidence of VFSS-related pneumonia and related factors. Overall, 696 VFSS cases were retrospectively reviewed. Cases in which blood culture was performed within 3 days after VFSS due to newly developed infectious signs were considered as post-VFSS infection cases. Pneumonia was suspected when there was some evidence of respiratory infectious signs in clinical, radiological, and laboratory findings. The underlying disease, clinical signs, and VFSS findings of the pneumonia group were assessed. Among 696 cases, pneumonia was diagnosed in 15 patients. The patients in the pneumonia group tended to be older and had higher aspiration rate on VFSS than those in the non-pneumonia group. In the pneumonia group, 2 patients showed no aspiration during VFSS. In 6 patients, pneumonia developed after massive aspiration of gastric content in 5 patients and inappropriate oral feeding with risk of aspiration before VFSS in 1 patient. Only 7 patients (1.0 %) were finally determined as having VFSS-related pneumonia. In conclusion, the 72-h incidence of VFSS-related pneumonia was 1.0 %. Old age and severity of swallowing difficulty are associated with occurrence of pneumonia.

A comparison between time to clinical stability in community-acquired aspiration pneumonia and community-acquired pneumonia

Antimicrobial therapy has been the main stay of therapy of community-acquired aspiration pneumonia (CAAP), but the duration of treatment has not been established. The objective of this study was to describe the time to reach clinical stability in patients with aspiration pneumonia compared to community-acquired pneumonia (CAP). A retrospective case control study at two university affiliated centers encompassing 329 consecutive patients admitted with CAAP and 329 consecutive patients with CAP was conducted between 2007 and 2011. While the median time to stability for patients with CAP was distributed around a median of 4 days, there was a bimodal distribution for time to clinical stability in patients with CAAP with dual peaks at days 2 and 5, respectively. CAAP patients who required more than 2 days to achieve clinical stability had a higher mortality rate compared to those with 2 days or less [odds ratio (OR) 5.95, 95% CI 2.85-12.4], and a longer hospital stay (6.6 ± 5.8 vs. 3.9 ± 1.2 days; p < 0.001). None of the CAAP patients who achieved clinical stability in 2 days or less was transferred to a higher level of care. In a multivariate analysis, time to clinical stability was found to be an independent predictor of outcome in patients with CAAP (OR 2.59, 95% CI 2.02-3.32). Normalization of vital signs in aspiration pneumonia follows a distinct pattern from that of patients with CAP. Time to achieve clinical stability may assist in identifying CAAP patients who are likely to require a shorter hospital stay and a shorter course of antimicrobial therapy.

Surfactant lavage with lidocaine improves pulmonary function in piglets after HCl-induced acute lung injury

Acute respiratory distress syndrome (ARDS) is associated with significant morbidity and mortality. The pathophysiology of ARDS includes abnormalities of surfactant function as well as pulmonary inflammation. Immunomodulating drugs, like Lidocaine, have shown some success in decreasing inflammation in ARDS. We attempted to combine surfactant lavage's ability to reverse the surfactant dysfunction, while acting as a vehicle to deliver Lidocaine. Gravity-driven surfactant (Infasurf) lavage (35 ml/kg) was administered alone or mixed with Lidocaine after severe HCl acid injury (0.3 N; 3 cc/kg) in neonatal piglets. Treatment groups included: control (C) ( n = 5), surfactant lavage (SL) (35 ml/kg-diluted Infasurf) ( n = 7) and SL mixed with Lidocaine (SL+L) ( n = 7). About 26-27% of the lavage was retained (phospholipid 73-74 mg/kg; Lidocaine 1.8 mg/kg). Oxygenation progressively increased in the SL and SL+L groups over the 4-hour period (at 240 min: C = 99 +/- 14; SL = 154 +/- 39; SL+L = 230 +/- 40 mmHg) ( p < 0.05). PaCO(2) increased in all groups from 43 +/- 0.3 to 55 +/- 0.7 mmHg. Only SL+L showed a reduction in PaCO(2) (at 240 min: C = 54 +/- 4; SL = 53 +/- 7; SL+L = 49 +/- 2 mmHg) ( p < 0.05). Finally, SL and SL + L had superior characteristics during the quasi-static pressure volume (PV) procedure as compared to Control ( p < 0.05). In our HCl ALI model, SL improved oxygenation and quasi-static lung compliance over C. The pulmonary function effects of SL were further enhanced by the addition of Lidocaine to the surfactant suspension. Combining therapeutic agents with surfactant lavage may be an effective strategy in ALI.

Prandial aspiration and pneumonia in an elderly population followed over 3 years

The purpose of our study was to prospectively determine pneumonia frequency and correlate it with prandial liquid aspiration and feeding status in frail elderly nursing home residents. Initially, 152 patients had video swallowing examinations (81 oropharyngeal dysphagia, 19 thoracic dysphagia, 52 without dysphagia). Those diagnosed with oropharyngeal impairment were subsequently managed with swallowing therapy or artificial feeding modalities. Patients were followed for 3 years (unless they expired earlier) and clinical courses were categorized according to the degree of prandial aspiration and feeding (PAF) status. Subjects with new lung infiltrates persisting for at least 5 days with appropriate clinical findings were diagnosed as having pneumonia and were classified according to the PAF status months in which these findings occurred. Fifty-six pneumonias were diagnosed during 4,280 months with the following frequencies: no aspiration months 0.6%; minor aspiration months 0.9%; major aspiration/oral feeding months 1.3%; major aspiration/artificial feeding months 4.4%, p < 0.001. Our results indicate that there is not a simple and obvious relation between prandial liquid aspiration and pneumonia. Artificial feeding does not seem to be a satisfactory solution for preventing pneumonia in elderly prandial aspirators.

Acid aspiration-induced lung injury in rabbits is mediated by interleukin-8-dependent mechanisms

Acid aspiration lung injury may be mediated primarily by neutrophils recruited to the lung by acid-induced cytokines. We hypothesized that a major acid-induced cytokine was IL-8 and that a neutralizing anti-rabbit-IL-8 monoclonal antibody (ARIL8.2) would attenuate acid-induced lung injury in rabbits. Hydrochloric acid (pH = 1.5 in 1/3 normal saline) or 1/3 normal saline (4 ml/kg) was instilled into the lungs of ventilated, anesthetized rabbits. The rabbits were studied for 6 or 24 h. In acid-instilled rabbits without the anti-IL-8 monoclonal antibody, severe lung injury developed in the first 6 h; in the long-term experiments, all rabbits died with lung injury between 12 and 14 h. In acid-instilled rabbits given the anti-IL-8 monoclonal antibody (2 mg/kg, intravenously) either as pretreatment (5 min before the acid) or as treatment (1 h after the acid), acid-induced abnormalities in oxygenation and extravascular lung water were prevented and extravascular protein accumulation was reduced by 70%; in the long-term experiments, anti-IL-8 treatment similarly protected lung function throughout the 24-h period. The anti-IL-8 monoclonal antibody also significantly reduced air space neutrophil counts and IL-8 concentrations. This study establishes IL-8 as a critical cytokine for the development of acid-induced lung injury. Neutralization of IL-8 may provide the first useful therapy for this clinically important form of acute lung injury.

Is penicillin G an adequate initial treatment for aspiration pneumonia? A prospective evaluation using a protected specimen brush and quantitative cultures

OBJECTIVE

To evaluate the bacteriology of early aspiration pneumonia using a protected specimen brush and quantitative culture techniques, and whether penicillin G is adequate as initial treatment pending culture results.

PATIENTS AND METHODS

52 patients (of which 45 required mechanical ventilation) meeting usual clinical criteria for aspiration pneumonia were prospectively included. On admission, patients were given intravenous penicillin G and a protected specimen brush was performed < or = 48 h after.

RESULTS

Cultures of the brush were negative (< 10(3) CFU/ml) in 33 patients (1 had blood cultures positive with S. pneumoniae) and positive (> or = 10(3) CFU/ml) for S. pneumoniae in 2 patients. Seventeen patients had a positive culture (> or = 10(3) CFU/ml) for at least one penicillin G resistant microorganism, with a total of 20 organisms (S. aureus: 6; H. influenzae: 2; Enterobacteriaceae: 8; P. aeruginosa: 3; C. albicans: 1). In 4 of these patients, a penicillin-sensitive pathogen was also recovered in significant concentrations (S. pneumoniae: 2; Streptococcus sp.: 2). These 17 patients with a resistant pathogen did not differ from the 35 other patients with respect to need for ventilatory support and mortality rate. By contrast, they were older (61.1 +/- 21.9 vs. 42.9 +/- 18.8 years; p < 0.005) and required longer mechanical ventilation (6.1 +/- 4.6 vs. 3.5 +/- 2.7 days; p < 0.03) and hospitalization (11.2 +/- 8.8 vs. 6.7 +/- 4.7 days; p < 0.02). Of 17 patients 12 with penicillin G resistant organisms versus 0/35 without, were in-hospital patients and/or had a digestive disorder (p < 0.001).

CONCLUSION

The broad range of offending organisms seen in early aspiration pneumonia precludes use of any single empiric regimen, making protected specimen brush mandatory in many patients. Nevertheless, the involvement of S.pneumoniae in a notable proportion of our patients suggests that routine penicillin prophylaxis after early aspiration (at least in most patients with community-acquired aspiration) is warranted given the potential severity of pneumococcal sepsis in such patients.

Aspiration and the elderly

Aspiration is prevalent in the elderly but its association with impairment of oral intake and gastroesophageal reflux is often misunderstood. This paper describes the causes, pathophysiology, and consequences of aspiration and their unique features in aged persons. It also explains how videofluoroscopic evaluation can assess current function while limiting factors that result in misinformation. The management of aspiration is discussed, emphasizing the importance and difficulties in maintaining functional well-being and possible complications of therapy.

An important role of silent aspiration of gastric contents as a cause of pulmonary complications following surgery for esophageal cancer

The progress of postoperative chest X-ray films was analyzed in patients who had undergone radical surgery for esophageal cancer at the second Department of Surgery, Osaka University Medical School from 1969 to 1981. We subsequently reached a conclusion that abnormal shadows were caused by the intratracheal aspiration of oropharyngeal secretions or gastric contents. In particular, the aspiration of gastric contents was considered to be a factor in the occurrence and aggravation of pneumonia. In order to prevent aspiration of gastric contents, a drainage tube was inserted into the stomach as a reconstructive organ and endotracheal intubation was maintained for more than 24 hours post-operatively in order to suction the tracheobronchial secretion. Consequently, the frequency of occurrence and the aggravation of pneumonia decreased and the operative mortality rate improved significantly.

Adherence of Pseudomonas aeruginosa to tracheal cells injured by influenza infection or by endotracheal intubation

Adherence of Pseudomonas aeruginosa to normal, injured, and regenerating tracheal mucosa was examined by scanning electron microscopy. Uninfected and influenza-infected murine tracheas were exposed to six strains of P. aeruginosa isolated from human sources and one strain of platn origin. All of the strains tested adhered to desquamating cells of the infected tracheas, but not to normal mucosa, the basal cell layer, or the regenerating epithelium. Adherence increased when the incubation time of the bacteria with the trachea was prolonged. Strains isolated from human tracheas appeared to adhere better than strains derived from the urinary tract. After endotracheal intubation of ferrets, P. aeruginosa adhered only to the injured cells and to areas of exposed basement membrane. We call this phenomenon "opportunistic adherence" and propose that alteration of the cell surfaces or cell injury facilitates the adherence of this bacterium and that adherence to injured cells may be a key to the pathogenesis of opportunistic Pseudomonas infections.