Nosocomial pneumonia: epidemiology and infection control

Oral care measures for preventing nursing home-acquired pneumonia

BACKGROUND

Pneumonia in residents of nursing homes can be termed nursing home-acquired pneumonia (NHAP). NHAP is one of the most common infections identified in nursing home residents and has the highest mortality of any infection in this population. NHAP is associated with poor oral hygiene and may be caused by aspiration of oropharyngeal flora into the lung. Oral care measures to remove or disrupt oral plaque might reduce the risk of NHAP. This is the first update of a review published in 2018.

OBJECTIVES

To assess effects of oral care measures for preventing nursing home-acquired pneumonia in residents of nursing homes and other long-term care facilities.

SEARCH METHODS

An information specialist searched CENTRAL, MEDLINE, Embase, one other database and three trials registers up to 12 May 2022. We also used additional search methods to identify published, unpublished and ongoing studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that evaluated the effects of oral care measures (brushing, swabbing, denture cleaning mouthrinse, or combination) in residents of any age in nursing homes and other long-term care facilities.

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed search results, extracted data, and assessed risk of bias in the included studies. We contacted study authors for additional information. We pooled data from studies with similar interventions and outcomes. We reported risk ratios (RRs) for dichotomous outcomes, mean differences (MDs) for continuous outcomes, and hazard ratios (HRs) or incidence rate ratio (IRR) for time-to-event outcomes, using random-effects models.

MAIN RESULTS

We included six RCTs (6244 participants), all of which were at high risk of bias. Three studies were carried out in Japan, two in the USA, and one in France. The studies evaluated one comparison: professional oral care versus usual oral care. We did not include the results from one study (834 participants) because it had been stopped at interim analysis.  Consistent results from five studies, with 5018 participants, provided insufficient evidence of a difference between professional oral care and usual (simple, self-administered) oral care in the incidence of pneumonia. Three studies reported HRs, one reported IRRs, and one reported RRs. Due to the variation in study design and follow-up duration, we decided not to pool the data. We downgraded the certainty of the evidence for this outcome by two levels to low: one level for study limitations (high risk of performance bias), and one level for imprecision. There was low-certainty evidence from meta-analysis of two individually randomised studies that professional oral care may reduce the risk of pneumonia-associated mortality compared with usual oral care at 24 months' follow-up (RR 0.43, 95% CI 0.25 to 0.76, 454 participants). Another study (2513 participants) reported insufficient evidence of a difference for this outcome at 18 months' follow-up. Three studies measured all-cause mortality and identified insufficient evidence of a difference between professional and usual oral care at 12 to 30 months' follow-up. Only one study (834 participants) measured the adverse effects of the interventions. The study identified no serious events and 64 non-serious events, the most common of which were oral cavity disturbances (not defined) and dental staining. No studies evaluated oral care versus no oral care.

AUTHORS' CONCLUSIONS

Although low-certainty evidence suggests that professional oral care may reduce mortality compared to usual care when measured at 24 months, the effect of professional oral care on preventing NHAP remains largely unclear. Low-certainty evidence was inconclusive about the effects of this intervention on incidence and number of first episodes of NHAP. Due to differences in study design, effect measures, follow-up duration, and composition of the interventions, we cannot determine the optimal oral care protocol from current evidence.  Future trials will require larger samples, robust methods that ensure low risk of bias, and more practicable interventions for nursing home residents.

Oral care measures for preventing nursing home-acquired pneumonia

BACKGROUND

Pneumonia occurring in residents of long-term care facilities and nursing homes can be termed 'nursing home-acquired pneumonia' (NHAP). NHAP is the leading cause of mortality among residents. NHAP may be caused by aspiration of oropharyngeal flora into the lung, and by failure of the individual's defence mechanisms to eliminate the aspirated bacteria. Oral care measures to remove or disrupt oral plaque might be effective in reducing the risk of NHAP.

OBJECTIVES

To assess effects of oral care measures for preventing nursing home-acquired pneumonia in residents of nursing homes and other long-term care facilities.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 15 November 2017), the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library, 2017, Issue 10), MEDLINE Ovid (1946 to 15 November 2017), and Embase Ovid (1980 to 15 November 2017) and Cumulative Index to Nursing and Allied Health Literature (CINAHL; 1937 to 15 November 2017). The US National Institutes of Health Trials Registry (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases. We also searched the Chinese Biomedical Literature Database, the China National Knowledge Infrastructure, and the Sciencepaper Online to 20 November 2017.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that evaluated the effects of oral care measures (brushing, swabbing, denture cleaning mouthrinse, or combination) in residents of any age in nursing homes and other long-term care facilities.

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed search results, extracted data, and assessed risk of bias in the included studies. We contacted study authors for additional information. We pooled data from studies with similar interventions and outcomes. We reported risk ratio (RR) for dichotomous outcomes, mean difference (MD) for continuous outcomes, and hazard ratio (HR) for time-to-event outcomes, using random-effects models.

MAIN RESULTS

We included four RCTs (3905 participants), all of which were at high risk of bias. The studies all evaluated one comparison: professional oral care versus usual oral care. We did not pool the results from one study (N = 834 participants), which was stopped at interim analysis due to lack of a clear difference between groups.We were unable to determine whether professional oral care resulted in a lower incidence rate of NHAP compared with usual oral care over an 18-month period (hazard ratio 0.65, 95% CI 0.29 to 1.46; one study, 2513 participants analysed; low-quality evidence).We were also unable to determine whether professional oral care resulted in a lower number of first episodes of pneumonia compared with usual care over a 24-month period (RR 0.61, 95% CI 0.37 to 1.01; one study, 366 participants analysed; low-quality evidence).There was low-quality evidence from two studies that professional oral care may reduce the risk of pneumonia-associated mortality compared with usual oral care at 24-month follow-up (RR 0.41, 95% CI 0.24 to 0.72, 507 participants analysed).We were uncertain whether or not professional oral care may reduce all-cause mortality compared to usual care, when measured at 24-month follow-up (RR 0.55, 95% CI 0.27 to 1.15; one study, 141 participants analysed; very low-quality evidence).Only one study (834 participants randomised) measured adverse effects of the interventions. The study identified no serious events and 64 non-serious events, the most common of which were oral cavity disturbances (not defined) and dental staining.No studies evaluated oral care versus no oral care.

AUTHORS' CONCLUSIONS

Although low-quality evidence suggests that professional oral care could reduce mortality due to pneumonia in nursing home residents when compared to usual care, this finding must be considered with caution. Evidence for other outcomes is inconclusive. We found no high-quality evidence to determine which oral care measures are most effective for reducing nursing home-acquired pneumonia. Further trials are needed to draw reliable conclusions.

Predicting nosocomial lower respiratory tract infections by a risk index based system

Although belonging to one of the most common type of nosocomial infection, there was currently no simple prediction model for lower respiratory tract infections (LRTIs). This study aims to develop a risk index based system for predicting nosocomial LRTIs based on data from a large point-prevalence survey. Among the 49328 patients included, the prevalence of nosocomial LRTIs was 1.70% (95% confidence interval [CI], 1.64% to 1.76%). The areas under the receiver operating characteristic (ROC) curve for logistic regression and fisher discriminant analysis were 0.907 (95% CI, 0.897 to 0.917) and 0.902 (95% CI, 0.892 to 0.912), respectively. The constructed risk index based system also displayed excellent discrimination (area under the ROC curve: 0.905 [95% CI, 0.895 to 0.915]) to identify LRTI in internal validation. Six risk levels were generated according to the risk score distribution of study population, ranging from 0 to 5, the corresponding prevalence of nosocomial LRTIs were 0.00%, 0.39%, 3.86%, 12.38%, 28.79% and 44.83%, respectively. The sensitivity and specificity of prediction were 0.87 and 0.79, respectively, when the best cut-off point of risk score was set to 14. Our study suggested that this newly constructed risk index based system might be applied to boost more rational infection control programs in clinical settings.

Dental hygiene intervention to prevent nosocomial pneumonias

Nosocomial and ventilator associated pneumonias that plague critically ill, elderly and long-term care residents could be reduced with effective oral hygiene practices facilitated collaboratively between nurses and dental hygienists.

BACKGROUND

Nosocomial pneumonias, specifically aspiration pneumonias and ventilator-associated pneumonias in the elderly and infirm have become a major health care issue, The provision of oral care in hospital and hospital-like facilities presents challenges that can prevent patients from receiving optimal oral care One sequela can be aspiration pneumonia which ranks first in mortality and second in morbidity among all nosocomial infections. Since aspiration pneumonia is linked to the colonization of oral bacteria in dental plaque and biofilm, it is time to look for creative solutions to integrating the expertise of dental hygienists into health care teams in these institutional settings.

METHODS

A comprehensive review of the literature was conducted regarding the etiology and prevalence of health care related pneumonias. Evidence describing the challenges and barriers that the nurses, nursing staff, and dental hygienists face in the provision of oral care in hospitals and long-term care facilities is provided. Intercollaborative solutions to providing optimal oral care in hospitals and long-term care facilities are suggested.

CONCLUSION

Dental hygienists have the expertise and practice experience to provide oral care in hospitals, long-term care and residential facilities. They can contribute to solving oral care challenges through intercollaboration with other health care team members. Yet, there are long-standing systemic barriers that must be addressed in order to provide this optimal care. Dental hygienists becoming better assimilated within the total health care team in hospital and residential facilities can positively impact the suffering, morbidity and mortality associated with aspiration pneumonias.

BAL for pneumonia prevention in tracheostomy patients: A clinical trial study

Objective: To evaluate the role of flexible bronchoscopy (FB) and bronchoalveolar lavage (BAL) on pneumonia prevention of tracheostomy patients in intensive care unit.

Methodology: This clinical trial was conducted on 67 head-injury patients who needed tracheostomy. The eligible patients were divided into two groups of different methods for removing the airway secretions. In intervention group, FB and BAL was added to routine conventional methods for airway clearance. Patients were followed for signs and symptoms of pneumonia.

Results: The risk of nosocomial pneumonia decreased from 35% to 14% in intervention group. The days of hospital stay were significantly reduced with bronchoscopic method.

Conclusions: Flexible Bronchoscopy is recommended to all ICU admitted patients that have tracheostomy tube and high volume of secretion in their airways. It can not only prevent the pneumonia formation decrease the morbidity and mortality rate but it can even shorten the ICU stay time and consequently reduce the costs of treatment.

Early-onset ventilator-associated pneumonia in adults randomized clinical trial: comparison of 8 versus 15 days of antibiotic treatment

PURPOSE

The optimal treatment duration for ventilator-associated pneumonia is based on one study dealing with late-onset of the condition. Shortening the length of antibiotic treatment remains a major prevention factor for the emergence of multiresistant bacteria.

OBJECTIVE

To demonstrate that 2 different antibiotic treatment durations (8 versus 15 days) are equivalent in terms of clinical cure for early-onset ventilator-associated pneumonia.

METHODS

Randomized, prospective, open, multicenter trial carried out from 1998 to 2002.

MEASUREMENTS

The primary endpoint was the clinical cure rate at day 21. The mortality rate was evaluated on days 21 and 90.

RESULTS

225 patients were included in 13 centers. 191 (84.9%) patients were cured: 92 out of 109 (84.4%) in the 15 day cohort and 99 out of 116 (85.3%) in the 8 day cohort (difference = 0.9%, odds ratio = 0.929). 95% two-sided confidence intervals for difference and odds ratio were [-8.4% to 10.3%] and [0.448 to 1.928] respectively. Taking into account the limits of equivalence (10% for difference and 2.25 for odds ratio), the objective of demonstrative equivalence between the 2 treatment durations was fulfilled. Although the rate of secondary infection was greater in the 8 day than the 15 day cohort, the number of days of antibiotic treatment remained lower in the 8 day cohort. There was no difference in mortality rate between the 2 groups on days 21 and 90.

CONCLUSION

Our results suggest that an 8-day course of antibiotic therapy is safe for early-onset ventilator-associated pneumonia in intubated patients.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01559753.

Prevention and Treatment of Gastrointestinal Complications in Patients on Mechanical Ventilation

There exists a complex, dynamic interaction between mechanical ventilation and the splanchnic vasculature that contributes to a myriad of gastrointestinal tract complications that arise during critical illness. Positive pressure-induced splanchnic hypoperfusion appears to play a pivotal role in the pathogenesis of these complications, the most prevalent of which are stress-related mucosal damage, gastrointestinal hypomotility and diarrhea. Furthermore, characteristics of the splanchnic vasculature make the gastrointestinal tract vulnerable to adverse effects related to positive pressure ventilation. While most of these complications seen in mechanically ventilated patients are reflections of altered gastrointestinal physiology, some may be attributed to medical interventions instituted to treat critical illness. Since maintenance of normal hemodynamics cannot always be achieved, pharmacologic prophylactic therapy has become a mainstay in the prevention of gastrointestinal complications in the intensive care unit. Improved understanding of the systemic effects of mechanical ventilation and greater application of lung-protective ventilatory strategies may potentially minimize positive pressure-induced reductions in splanchnic perfusion, systemic cytokine release and, consequently, reduce the incidence of gastrointestinal complications associated with mechanical ventilation. Herein, we discuss the pathophysiology of gastrointestinal complications associated with mechanical ventilation, summarize the most prevalent complications and focus on preventive strategies and available treatment options for these complications. The most common causes of gastrointestinal hemorrhage in mechanically ventilated patients are bleeding from stress-related mucosal damage and erosive esophagitis. In general, histamine H(2) receptor antagonists and proton pump inhibitors prevent stress-related mucosal disease by raising the gastric fluid pH. Proton pump inhibitors tend to provide more consistent pH control than histamine H(2) receptor antagonists. There is no consensus on the drug of choice for stress ulcer prophylaxis with several meta-analyses providing conflicting results on the superiority of any medication. Prevention of erosive esophagitis include careful use of nasogastric tubes and institution of strategies that improve gastric emptying. Many mechanically ventilated patients have gastrointestinal hypomotility and diarrhea. Treatment options for gastrointestinal motility are limited, thus, preventive measures such as correction of electrolyte abnormalities and avoidance of medications that impair gastrointestinal motility are crucial. Treatment of diarrhea depends on the underlying cause. When associated with Clostridium difficile infection antibacterial therapy should be discontinued, if possible, and treatment with oral metronidazole should be initiated.More studies are warranted to better understand the systemic effects of mechanical ventilation on the gastrointestinal tract and to investigate the impact of lung protective ventilatory strategies on gastrointestinal complications.

Clinical practice guidelines for hospital-acquired pneumonia and ventilator-associated pneumonia in adults

Hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) are important causes of morbidity and mortality, with mortality rates approaching 62%. HAP and VAP are the second most common cause of nosocomial infection overall, but are the most common cause documented in the intensive care unit setting. In addition, HAP and VAP produce the highest mortality associated with nosocomial infection. As a result, evidence-based guidelines were prepared detailing the epidemiology, microbial etiology, risk factors and clinical manifestations of HAP and VAP. Furthermore, an approach based on the available data, expert opinion and current practice for the provision of care within the Canadian health care system was used to determine risk stratification schemas to enable appropriate diagnosis, antimicrobial management and nonantimicrobial management of HAP and VAP. Finally, prevention and risk-reduction strategies to reduce the risk of acquiring these infections were collated. Future initiatives to enhance more rapid diagnosis and to effect better treatment for resistant pathogens are necessary to reduce morbidity and improve survival.

Suction regulators: a potential vector for hospital-acquired pathogens

The role of suction regulators in nosocomial infections has, to our knowledge, not been studied. A sampling of devices used in hospitals was conducted. Many regulators (173 [37%] of 470) were found to be colonized. A suction circuit model revealed that pathogens can disseminate throughout the circuit (retrograde and antegrade), colonizing an experimental patient stomach.

Impact of oral hygiene on prevention of ventilator-associated pneumonia in neuroscience patients

Ventilator-associated pneumonia is one of the most frequent complications among critically ill patients. Growth of pathogenic bacteria in dental plaque may serve as the source of these infections. This performance improvement initiative evaluated an aggressive oral care approach to prevent the accumulation of plaque containing bacteria. Our data support the use of these oral care measures and deep oral-pharyngeal suctioning for the prevention of aspiration of oral contents.

Neumonía por Pseudomonas aeruginosa

Pseudomonas aeruginosa is one of the leading causes of Gram-negative nosocomial pneumonia. It is the most common cause of ventilator-associated pneumonia and carries the highest mortality among hospital-acquired infections. P. aeruginosa produces a large number of toxins and surface components that make it especially virulent compared with other microorganisms. These include pili, flagella, membrane bound lipopolysaccharide, and secreted products such as exotoxins A, S and U, elastase, alkaline protease, cytotoxins and phospholipases. The most common mechanism of infection in mechanically ventilated patients is through aspiration of upper respiratory tract secretions previously colonized in the process of routine nursing care or via contaminated hands of hospital personnel. Intravenous therapy with an antipseudomonal regimen should be started immediately when P. aeruginosa pneumonia is suspected or confirmed. Empiric therapy with drugs active against P. aeruginosa should be started, especially in patients who have received previous antibiotics or present late-onset pneumonia.

Strategies for prophylaxis and treatment for aspiration

The absolute incidence of aspiration is difficult to define because of its relatively low occurrence and difficulty in diagnosis. The gastric volume predisposing to aspiration is larger than 30 ml. Fasting times for fluids have reduced; however, a large meal may require 9 hours of preoperative fasting. Preoperative carbohydrate-enriched beverages may attenuate postoperative catabolism. Aspiration occurs most frequently during induction and laryngoscopy. Awake fibre-optic intubation may be a suitable alternative in high-risk cases for aspiration. The role of cricoid pressure in anaesthesia needs re-evaluation as radiological and clinical evidence suggest that it may be ineffective and may impede intubation and ventilation. Chemoprophylaxis does not reduce the severity of aspiration pneumonitis as gastric bile is unaffected by these agents and induces a worse pneumonitis than gastric acid. Patients may be discharged home 2 hours after aspirating provided they are clinically unaffected and have postoperative surveillance.

Oral Care Interventions in Critical Care: Frequency and Documentation

• Background No data have been collected to describe the products, methods, and frequency of oral care needed to reduce dental plaque, oral colonization, and ventilator-associated pneumonia in critically ill patients.

• Objectives To describe the frequency of use of oral care interventions reported by nurses in several intensive care units in a large southeastern medical center.

• Methods Staff members completed a written survey describing their oral care practices, and oral care interventions were recorded from the unit’s flow sheet for the previous 24 hours for all patients at 5 randomly selected times during 1 month.

• Results Most respondents (75%) reported providing oral care 2 or 3 times daily for nonintubated patients, and 72% reported providing care 5 times daily or more for intubated patients. However, oral care was documented on the unit’s flow sheet a mean of 1.2 times per patient. Reported use of toothpaste and a toothbrush was significantly greater in nonintubated patients (P < .001), and use of a sponge toothette was significantly greater in intubated patients (P < .001). Nurses’ mean rating of oral care priority was 53.9 on a 100-point scale.

• Conclusions Despite evidence that they are ineffective for plaque removal, sponge toothettes remain the primary tool for oral care, especially in intubated patients in intensive care units. Nurses report frequent oral care interventions, but few are documented. Education and focus on good oral care strategies are required; nursing research to delineate the best procedure for all patients in intensive care units is needed.

Pneumonia after cardiac surgery is predictable by tracheal aspirates but cannot be prevented by prolonged antibiotic prophylaxis

BACKGROUND

The purpose of this study was to assess the value of tracheal aspirate as a predictor of pneumonia after coronary artery bypass grafting and to evaluate the efficacy of prolonged perioperative antibiotic prophylaxis.

METHODS

Tracheal aspirates of 500 patients undergoing coronary artery bypass grafting were taken immediately after intubation and analyzed for microorganisms by Gram stain and semiquantitative microbiologic cultures. All patients received 2 g ceftriaxone as a single-dose perioperative antibiotic prophylaxis before operation. Results of Gram stains were available before the patients were transferred to the intensive care unit. After the results were known, both groups of patients (positive Gram stain, group 1; negative Gram stain, group 2) were randomly assigned to either conventional antibiotic prophylaxis (A), consisting of ceftriaxone 2 g on postoperative day 1, or prolonged antibiotic prophylaxis (B), with ticarcillin + clavulanic acid 3 x 5.2 g during 72 hours.

RESULTS

From 500 patients, 91 had a positive Gram stain whereas 409 had a negative one. The incidence of pneumonia was significantly higher in patients with preoperative positive tracheal aspirates (15.3%) than in patients with a negative one (3.6%; p < 0.01). However, prolonged prophylaxis did not reduce the rate of postoperative pneumonia, which was as high as 13% in untreated positive patients versus 17% in treated positive patients, and 2% in untreated negative patients versus 4% in treated patients. In patients who had pneumonia, there was a high correlation between the microorganisms found in preoperative aspirates and those observed when aspirates were repeated (100% correlation in patients with conventional antibiotic prophylaxis and 87% in those with prolonged prophylaxis).

CONCLUSIONS

Early postoperative pneumonia (<7 days) is most likely caused by microorganisms that colonize the respiratory tract before operation. The risk of pulmonary infection after coronary artery bypass grafting can be predicted from the preoperative tracheal aspirates. Prolonged perioperative antibiotic prophylaxis has no efficacy in reducing the incidence of pulmonary infections.

GI complications in patients receiving mechanical ventilation

Mechanical ventilation (MV) can be lifesaving by maintaining gas exchange until the underlying disorders are corrected, but it is associated with numerous organ-system complications, which can significantly affect the outcome of critically ill patients. Like other organ systems, GI complications may be directly attributable to MV, but most are a reflection of the severity of the underlying disease that required intensive care. The interactions of the underlying critical illness and MV with the GI tract are complex and can manifest in a variety of clinical pictures. Incorporated in this review are discussions of the most prevalent GI complications associated with MV, and current diagnosis and management of these problems.

Risk factors for nosocomial pneumonia in critically ill trauma patients

OBJECTIVE

To determine risk factors for nosocomial pneumonia in critically ill trauma patients.

DESIGN

Prospective cohort study.

SETTING

The trauma intensive care unit (ICU) of a 1500-bed tertiary-care hospital.

PATIENTS

All critically ill trauma patients (n = 103) admitted consecutively between November 1995 and October 1996.

INTERVENTIONS

A comparison of data recorded at the time of ICU admission and during the clinical evolution in patients with (n = 23) and without (n = 80) nosocomial pneumonia was made. Data referred mainly to possible risk factors were recorded; they also included factors related to pneumonia etiology and evolutive factors. Predictors of nosocomial pneumonia were assessed by logistic regression analysis.

MEASUREMENTS AND MAIN RESULTS

The presence of significant growth on quantitative cultures of the protected specimen brush (> or = 103 colony forming units/mL) was required to accept pneumonia as microbiologically proven, as well as the concurrence of a cohort of clinical and radiologic signs. Twenty-three (22.3%) patients developed nosocomial pneumonia. The mean age of these patients was 41.7 yrs; 18 of them (78.3%) were men. The microorganisms isolated in significant concentrations were Acinetobacter baumanii (ten cases), Staphylococcus aureus (11 cases), Pseudomonas aeruginosa (five cases), Haemophilus influenzae (two cases), and Klebsiella pneumoniae, Citrobacter freundii, Serratia marcescens, Enterococcus spp., Enterobacter spp., coagulase-negative Staphylococcus, and Streptococcus intermedius (one case each one). Risk factors for pneumonia by univariate analysis included nasogastric tube; continuous enteral feeding; prolonged mechanical ventilation (>1 day); use of H2-receptor antagonist, sucralfate, muscle relaxants, corticosteroids, barbiturates, and inotropic agents; positive end-expiratory pressure; intense sedation; re-intubation; tracheotomy; urgent brain computed tomography (CT) scan; craniotomy; iatrogenic event; and hyperventilation. The mortality rate was 43.5% (10 of 23) in the nosocomial pneumonia group and 18.8% in patients without nosocomial pneumonia (p =.02). Also, the mean stay in the ICU, the therapeutic charge (measured with total and mean punctuation of the Therapeutic Intervention Scoring System) and the complications, infectious and noninfectious, of the clinical evolution were significantly more frequent in patients with nosocomial pneumonia than in those without pneumonia (p <.05). In the multivariate analysis, continuous enteral feeding, craniotomy, prolonged mechanical ventilation (>24 hrs), use of positive end-expiratory pressure, and corticotherapy were independent predictors of nosocomial pneumonia.

CONCLUSIONS

It seems that factors related to the patient's clinical course, rather than variables registered on the first days of ICU admission, are those that would exert an influence on the development of nosocomial pneumonia in critically ill trauma patients. In this way, from our point of view, in our study the main risk factors are the use of prolonged mechanical ventilation (>4 hrs) and positive end-expiratory pressure. At the same time, we can conclude that the reduction of this infection incidence could decrease the mean stay in the ICU, the therapeutic charge, and the prognosis in terms of mortality and morbidity.

Nosocomial pulmonary infection by antimicrobial-resistant bacteria of patients hospitalized in intensive care units: risk factors and survival

The objectives of this study were to identify the risk factors of nosocomial pulmonary infection (NPI) in intensive care units (ICUs) associated with antimicrobial-resistant bacteria (NPI-ARB) and to compare survival after NPI-ARB with NPI due to antimicrobial-sensitive bacteria (NPI-ASB). We analysed data from a surveillance network monitoring nosocomial infections in 27 mixed ICUs in the south-east of France. NPI surveillance data were recorded for 628 patients with documented NPI. The patients were stratified into 2 groups by type of pneumonia: NPI-ASB (445 patients) vs. NPI-ARB (183 patients). Variables associated with NPI-ARB were identified++ by multivariate logistic regression. Survival was calculated using the Kaplan-Meier method. A medical condition for ICU admission [odds ratio (OR) 1.98, 95% confidence interval (95% CI) 1.35-2.91], transfer from another hospital ward [OR 1.66, 95% CI (1.14-2.42)], a colonized central venous catheter [OR 3.47, 95% CI (1.46-8.21)], a stay of [eight days [OR 1.02, 95% CI (1.01-1. 05)] and mechanical ventilation [OR 2.10, 95% CI (1.31-3.36)] were independent risk factors of NPI-ARB. Median survival was 35 days after NPI-ARB and 32 days after NPI-ASB (P=0.92). Survival after bacterial NPI was not associated with antimicrobial susceptibility.

Pseudomonas aeruginosa septicaemia from an oral source

Oral colonisation with aerobic Gram-negative bacilli (AGNB) is abnormal and usually indicates a medically compromised state in the host. It has been postulated that oral colonisation with AGNB may predispose a patient to serious systemic infection, but proof of this assertion is lacking. This report describes an elderly patient who had oral colonisation of Pseudomonas aeruginosa and developed septicaemia from an identical strain of this bacterium.

The gut: the 'motor' of multiple organ dysfunction syndrome?

Abnormal colonization, gut-origin infections, and bacterial translocation are all signs of gut dysfunction that may be implicated in the pathogenesis of multiple organ dysfunction syndrome (MODS). This review summarizes and updates relevant experimental and clinical data that have attempted to correlate these phenomena with the development of MODS and to answer whether or not the gut is the 'motor' of MODS. The presented data suggest that, in some patients, gut dysfunction may precede the development of MODS. However, in most patients, this relationship is less obvious. The gut may still be one of the motors of MODS; however, it does not appear that this motor is fueled by the systemic spread of bacteria. Bacteria may play a role on a local gut-associated level in initiating and perpetuating the production of local inflammatory mediators that may produce distant organ injury.

Cross-colonisation with Pseudomonas aeruginosa of patients in an intensive care unit

BACKGROUND

Ventilator-associated pneumonia (VAP) caused by Pseudomonas aeruginosa is usually preceded by colonisation of the respiratory tract. During outbreaks, colonisation with P aeruginosa is mainly derived from exogenous sources. The relative importance of different pathways of colonisation of P aeruginosa has rarely been determined in non-epidemic settings.

METHODS

In order to determine the importance of exogenous colonisation, all isolates of P aeruginosa obtained by surveillance and clinical cultures from two identical intensive care units (ICUs) were genotyped with pulsed field gel electrophoresis.

RESULTS

A total of 100 patients were studied, 44 in ICU 1 and 56 in ICU 2. Twenty three patients were colonised with P aeruginosa, seven at the start of the study or on admission and 16 of the remaining 93 patients became colonised during the study. Eight patients developed VAP due to P aeruginosa. The incidence of respiratory tract colonisation and VAP with P aeruginosa in our ICU was similar to that before and after the study period, and therefore represents an endemic situation. Genotyping of 118 isolates yielded 11 strain types: eight in one patient each, two in three patients each, and one type in eight patients. Based on chronological evaluation and genotypical identity of isolates, eight cases of cross-colonisation were identified. Eight (50%) of 16 episodes of acquired colonisation and two (25%) of eight cases of VAP due to P aeruginosa seemed to be the result of cross-colonisation.

CONCLUSIONS

Even in non-epidemic settings cross-colonisation seems to play an important part in the epidemiology of colonisation and infection with P aeruginosa.

Prospective randomized comparison of imipenem-cilastatin and piperacillin-tazobactam in nosocomial pneumonia or peritonitis

Nosocomial pneumonia and acute peritonitis may be caused by a wide array of pathogens, and combination therapy is often recommended. We have previously shown that imipenem-cilastatin monotherapy was as efficacious as the combination of imipenem-cilastatin plus netilmicin in these two settings. The efficacy of imipenem-cilastatin is now compared to that of piperacillin-tazobactam as monotherapy in patients with nosocomial pneumonia or acute peritonitis. Three hundred seventy one patients with nosocomial pneumonia or peritonitis were randomly assigned to receive either imipenem-cilastatin (0.5 g four times a day) or piperacillin-tazobactam (4.5 g three times a day). Three hundred thirteen were assessable (154 with nosocomial pneumonia and 159 with peritonitis). For nosocomial pneumonia, clinical-failure rates in the piperacillin-tazobactam group (13 of 75 [17%]) and in the imipenem-cilastatin group (23 of 79 [29%]) were similar (P = 0.09), as were the numbers of deaths due to infection (6 in the imipenem-cilastatin group [8%], 7 in the piperacillin-tazobactam group [9%]) (P = 0.78). For acute peritonitis, clinical success rates were comparable (piperacillin-tazobactam, 72 of 76 [95%]; imipenem-cilastatin, 77 of 83 [93%]). For infections due to Pseudomonas aeruginosa, 45 patients had nosocomial pneumonia (21 in the piperacillin-tazobactam group and 24 in the imipenem-cilastatin group) and 10 had peritonitis (5 in each group). In the patients with nosocomial pneumonia, clinical failure was less frequent in the piperacillin-tazobactam group (2 of 21 [10%]) than in the imipenem-cilastatin [corrected] group (12 of 24 [50%]) (P = 0.004). Bacterial resistance to allocated regimen was the main cause of clinical failure (1 in the piperacillin-tazobactam group and 12 in the imipenem-cilastatin group). For the patients with peritonitis, no difference in clinical outcome was observed (five of five cured in each group). The overall frequencies of adverse events related to treatment in the two groups were similar (24 in the piperacillin-tazobactam group, 22 in the imipenem-cilastatin group). Diarrhea was significantly more frequent in the piperacillin-tazobactam group (10 of 24) than in the imipenem-cilastatin group (2 of 22). This study suggests that piperacillin-tazobactam monotherapy is at least as effective and safe as imipenem-cilastatin monotherapy in the treatment of nosocomial pneumonia or peritonitis. In P. aeruginosa pneumonia, piperacillin-tazobactam achieved a better clinical efficacy than imipenem-cilastatin, due to reduced development of microbiological resistance. Tolerance was comparable, with the exception of diarrhea, which was more frequent with piperacillin-tazobactam.

Risks and routes for ventilator-associated pneumonia with Pseudomonas aeruginosa

In a prospective study, we screened specimens from 190 mechanically ventilated patients hospitalized in a surgical intensive care unit, and from the environment to assess risks and routes of colonization/infection. Specimens from various sites were collected on admission and once a week throughout each patient's stay. All P. aeruginosa isolates were typed by determination of DNA patterns. Data were collected from patients to identify risk factors. In vitro production of exoenzymes of different strains were compared. Forty-four patients were colonized with P. aeruginosa on the bronchopulmonary tract and 13 suffered from pneumonia. The 7-d and 14-d Kaplan-Meier rates of colonization were 2.21 and 7.03%. Twenty-one patterns of bronchopulmonary tract isolates were isolated from single patients and 10 from several patients. The lower airway was often the first site of colonization. The contribution of environment to patient colonization appeared to be small. The length of hospitalization, the previous use of third-generation cephalosporins less effective against P. aeruginosa, and chronic obstructive pulmonary disease were the most significant predictors of colonization/infection. The in vitro exoprotein production was not correlated with the presence of pneumonia. Our study may be useful in identifying which patients in the mechanically ventilated population are at greater risk of P. aeruginosa pneumonia.

Community-acquired pneumonia due to Escherichia coli

OBJECTIVE: To describe the features of community-acquired Escherichia coli pneumonia and to compare these patients with patients with pneumonia caused by other etiologic agents. PATIENTS AND METHODS: This prospective study was carried out at five medical institutions in three geographic locations---Pittsburgh, PA, Boston, MA and Halifax, NS. Pneumonia etiology was assigned, based on results of microbiological investigations, by a committee consisting of five investigators using rules established prior to the study. Demographic and clinical features and outcomes of patients with E. coli pneumonia were compared with those of pneumonia due to other microorganisms. RESULTS: Nineteen patients (9 (47.4%) blood culture positive) had pneumonia due to E. coli and 430 (69 (16.0%) blood culture positive) had pneumonia caused by other etiologic agents. E. coli was the second most common cause of bacteremic pneumonia. The E. coli patients were older, and more likely to be female, from a nursing home and confused compared with patients with pneumonia due to other microbial agents. They were more severely ill as measured by a validated pneumonia specific severity of illness scoring measure. Although there was no in-hospital mortality for the patients with E. coli pneumonia, the 90-day mortality was 21%. Thirty-two (7.4%) of the patients with pneumonia due to other agents died in hospital and the 90-day mortality rate was 13.5% (p NS). Eight of the 19 patients with E. coli pneumonia were admitted from a nursing home and an additional four patients (63.2%) were discharged to such a facility. In contrast, only 44 (10.2%) of the patients with pneumonia due to other agents were discharged to a nursing home (p<0.001). CONCLUSIONS: Patients diagnosed with E. coli pneumonia are frequently bacteremic. They are older than patients with pneumonia due to other etiologies, and more likely to be female, from a nursing home and severely ill. Despite the absence of in-hospital mortality, 21% of these patients died within 90 days of presentation.

Nosocomial pneumonia in the critical care unit

Nosocomial pneumonia poses a major threat to the recovery of patients receiving mechanical ventilation. In addition, nosocomial pneumonia is often difficult to diagnose. This article examines the extent of the threat and some of the difficulties facing the critical care physician when diagnosing nosocomial pneumonia.

Ventilator-associated pneumonia: clinical significance and implications for nursing

Pneumonia is the second most common nosocomial infection in the United States and the leading cause of death from nosocomial infections. Intubation and mechanical ventilation greatly increase the risk of bacterial pneumonia. Ventilator-associated pneumonia (VAP) occurs in a patient treated with mechanical ventilation, and it is neither present nor developing at the time of intubation; it is a serious problem--with significant morbidity and mortality rates. Aspiration of bacteria from the oropharynx, leakage of contaminated secretions around the endotracheal tube, patient position, and cross-contamination from respiratory equipment and health care providers are important factors in the development of VAP. Nurses caring for patients treated with mechanical ventilation must recognize risk factors and include strategies for reducing these factors as part of their nursing care. This article summarizes the literature related to VAP: its incidence, associated factors, diagnosis, and current therapies, with an emphasis on nursing implications in the care of these patients.

Microbial colonization of closed-system suction catheters used in liver transplant patients

The microbial colonization and the associated risk of respiratory infection during the application of a multiple-use closed-system suction catheter (CSSC) and a single-use open-system suction catheter (OSSC) on liver transplant patients was evaluated in this preliminary study. The cost differential for the two systems was also compared. Twenty post-orthotopic liver transplant (OLTx) patients who were mechanically ventilated via an endotracheal (ET) tube were studied. Ten subjects were randomly allocated ET suction by the CSSC and 10 with OSSC. Both groups were similar according to age, sex, clinical severity, presence of a naso-gastric tube, use of H2 antagonists and antibiotics used. Standard protocols were followed to intubate and suction the patients and to change ventilatory equipment. Suctioning performed with the CSSC did not significantly increase the risk of microbial colonization of the respiratory tract. Similarly there was no apparent difference in the incidence of nosocomial pneumonia between the two suction systems, based on the microbiological and clinical data. The mean daily cost of using the CSSC compared to the OSSC was 11.6 times higher. This may be balanced by a reduction in nursing time and reduced risk of spread of infection associated with the CSSC.

Scoring system for nosocomial pneumonia in ICUs

OBJECTIVE

To develop a scoring system for stratifying patients in intensive care units (ICUs) by risk of developing nosocomial pneumonia (NP), based on variables generally available in an ICU, and to determine the probability of a patient developing NO in the ICU.

DESIGN AND SETTING

a 2-year prospective cohort study conducted in a medical and surgical ICU.

PATIENTS

756 patients admitted to the ICU for 48 h or more were followed up until the development of NP or death or discharge from the ICU.

MEASUREMENTS AND RESULTS

129 (17.1%) patients developed NP, 106 (14%) in the first 2 weeks. The following independent risk factors were identified by multivariate analysis: no infection on admission [relative risk (RR) = 3.1, 95% confidence intervals (CI) = 2.0 to 4.81; thorax drainage (RR = 2.1, 95% CI = 1.2 to 3.5); administration of antacids (RR = 2.1, 95% CI = 1.4 to 3.1); partial pressure of oxygen (PO2) > 110 mmHg (RR = 1.6, 95% CI = 1.0 to 2.6); administration of coagulation factors (RR = 1.8 95% CI = 1.0 to 3.2); male gender (RR = 2.7, 95% CI = 1.2 to 6.3); urgent surgery (RR = 2.4, 95% CI = 0.9 to 6.4); and neurological diseases (RR = 4.2, 95% CI = 1.9 to 9.4). To obtain a predictive risk index for NP, a scoring system was developed using a multivariate model. The probability of developing NP varied between 11.0% in the lowest risk group and 42.3% in the highest risk group. The patients' risk of acquiring NP was seven times higher in the highest score category (i.v.) than in the lowest one (I).

CONCLUSIONS

ICU patients can be stratified into high- and low-risk groups for NP. No infection on admission, thorax drainage, administration of antacids, and PO2 > 110 mmHg were associated with a higher risk of NP during the entire 2-week period.

Food and microbiological problems in the newborn: data and practice

We have reviewed the relationships of food, nutrition and feeding practices to various infections in the newborn. Tentative conclusions are made: (a) the initial use of human milk (raw or pasteurized) continues to offer advantages in the care of babies in intensive care; (b) attempts to mimic the microbiological effects of breast milk by manipulation of the composition of infant formulas have so far achieved little success, but this is a rapidly developing field; (c) we are wary of the widespread use of breast milk "fortifiers" until there is evidence that they do not adversely affect the protective properties of breast milk; (d) the doubtful advantages of nasojejunal feeding need to be weighed against the increased bacterial contamination of the upper small bowel; (e) systems monitoring in milk kitchens and the handling of feeds in the neonatal unit are an integral part of comprehensive neonatal care; (f) to limit nosocomial infection, particular attention to the faecal-food-oral route is necessary since there is potential for multiplication of initial contamination of food.

Serious Infections Caused by Pseudomonas Aeruginosa

Over the last 3 decades, Pseudomonas aeruginosa has become a leading cause of infectious morbidity and mortality in certain predisposed patient populations. It primarily affects those with impaired host defenses, and its prevalence in the hospital environment makes it an important nosocomial pathogen. Infection with this organism may result in a broad spectrum of clinical manifestations, many of which may be seen in the intensive care setting. This review focuses on epidemiology, clinical presentations, nad treatment of serious Pseudomonas infections.

Humidification in the intensive care unit. Prospective study of a new protocol utilizing heated humidification and a hygroscopic condenser humidifier

STUDY OBJECTIVE

Determine the utility of a proposed algorithm in allowing safe, efficient humidification in mechanically ventilated patients using both a hygroscopic condenser humidifier (HCH) and heated humidifier (HH).

DESIGN

A prospective study using an algorithm to chose humidification devices based on physical examination and sputum characteristics.

SETTING

All patients admitted to the surgical ICU.

PATIENTS

One hundred twenty consecutive patients requiring mechanical ventilation (MV) were studied.

INTERVENTIONS

Patients were examined by the attending respiratory care practitioner and given either an HCH or HH. If patients demonstrated any of the following--thick or tenacious secretions, core temperature < 32 degrees C, or bloody secretions--they were given an HH. All others used an HCH. If any of the above conditions occurred during HCH use, the patient was given an HH.

MEASUREMENTS AND RESULTS

Duration of ventilation, incidence of nosocomial pneumonia, ventilator circuit colonization, and mortality were determined for patients in each group. Cost of humidification devices, number of suctioning procedures per day, and volume of saline solution instilled were also recorded. Initially, 27 percent (32/120) of patients used an HH and 73 percent (88/120) used an HCH. During the study, ten patients required changing to an HH during HCH use. Patients in the HH group were more likely to have preexisting lung disease and had a longer duration of ventilation (83 +/- 21 h) and higher mortality (21 percent). Patients in the HCH group were more likely to be postoperative, had shorter durations of ventilation (38 +/- 14 h), and lower mortality (9 percent). There was no difference in the incidence of nosocomial pneumonia between the two groups (9 percent vs 6 percent) and endotracheal tube occlusion did not occur in either group. Circuit colonization was common in the HH group (64 percent) but rate in the HCH group (5 percent). Cost per day was significantly less for the HCH group ($4 vs $19.80). Patients who required a change from HCH to HH did so at a mean of 5 days.

CONCLUSION

The proposed algorithm resulted in cost-efficient and safe application of humidification devices in patients in the surgical ICU.