Guideline for prevention of nosocomial pneumonia

The Influence of pH Elevation on the Incidence of Nosocomial Pneumonia

Nosocomial pneumonia, one of the most common hos pital-acquired infectious diseases, is associated with sub stantial morbidity and mortality, approaching 50% in selected patients. Patients with alterations in their tracheobronchial tree or natural host-defense mecha nisms are at increased risk of developing pneumonia. Organisms gain access to the normally sterile tracheo bronchial tree primarily by aspiration of colonized oro pharyngeal gastric secretions. Risk factors for bacterial colonization and the development of nosocomial pneu monia include increased age, elevated pH of gastric con tents, postoperative state, nutritional status, severe underlying disease (for example, chronic obstructive pulmonary disease), administration of corticosteroids or other immunosuppressive therapy, and intubation or mechanical ventilation. High gastric volume may also increase the chance of aspiration of secretions in some high-risk patients.

Use of Ventilator Bundle and Staff Education to Decrease Ventilator-Associated Pneumonia in Intensive Care Patients

BACKGROUND

Ventilator-associated pneumonia (VAP), one of the most common hospital-acquired infections, has a high mortality rate.

OBJECTIVES

To evaluate the incidence of VAP in a multidisciplinary intensive care unit and to examine the effects of the implementation of ventilator bundles and staff education on its incidence.

METHODS

A 24-month-long before/after study was conducted, divided into baseline, intervention, and postintervention periods. VAP incidence and rate, the microbiological profile, duration of mechanical ventilation, and length of stay in the intensive care unit were recorded and compared between the periods.

RESULTS

Of 1097 patients evaluated, 362 met the inclusion criteria. The baseline VAP rate was 21.6 per 1000 ventilator days. During the postintervention period, it decreased to 11.6 per 1000 ventilator days (P = .01). Length of stay in the intensive care unit decreased from 36 to 27 days (P = .04), and duration of mechanical ventilation decreased from 26 to 21 days (P = .06).

CONCLUSIONS

VAP incidence was high in a general intensive care unit in a Greek hospital. However, implementation of a ventilator bundle and staff education has decreased both VAP incidence and length of stay in the unit.

Periodically Changing Ventilator Circuits Is Not Necessary to Prevent Ventilator-Associated Pneumonia When a Heat and Moisture Exchanger Is Used

Objective:

To analyze the efficacy of periodically changing ventilator circuits for decreasing the rate of ventilator-associated pneumonia when a heat and moisture exchanger (HME) is used for humidification. The Centers for Disease Control and Prevention recommended not changing the circuits periodically.

Design:

Randomized, controlled trial conducted between April 2001 and August 2002.

Setting:

A 24-bed, medical–surgical intensive care unit in a 650-bed, tertiary-care hospital.

Patients:

All patients requiring mechanical ventilation during more than 72 hours from April 2001 to August 2002.

Interventions:

Patients were randomized into two groups: (1) ventilation with change of ventilator circuits every 48 hours and (2) ventilation with no change of circuits. Throat swabs were taken on admission and twice weekly until discharge to classify pneumonia as endogenous or exogenous.

Results:

Three hundred four patients (143 from group 1 and 161 from group 2) with similar characteristics (age, gender, Acute Physiology and Chronic Health Evaluation II score, diagnostic group, and mortality) were analyzed. There was no significant difference in the rate of pneumonia between the groups (23.1% vs 23.0% and 15.5 vs 14.8 per 1,000 ventilator-days). There was no significant difference in the incidence of exogenous pneumonia per 1,000 days of mechanical ventilation (1.71 vs 1.25). There was no difference in the distribution of microorganisms causing pneumonia.

Conclusions:

Circuit change using an HME for humidification does not decrease pneumonia and represents an unnecessary cost.

Ventilator-Associated Pneumonia Bundle

The ventilator-associated pneumonia (VAP) bundle is a focus of many health care institutions. Many hospitals are conducting process-improvement projects in an attempt to improve VAP rates by implementing the bundle. However, this bundle is controversial in the literature, because the evidence supporting the VAP interventions is weak. In addition, definitions used for surveillance are interpreted differently than definitions used for clinical diagnosis. The variance in definitions has led to lower reported VAP rates, which may not be accurate. Because of the variance in definitions, the Centers for Disease Control and Prevention developed a ventilator-associated event algorithm. Health care institutions are under pressure to reduce the VAP infection rate, but correctly identifying VAP can be very challenging. This article reviews the current evidence related to VAP and provides insight into implementing a suggested revision of the care of patients being treated with mechanical ventilation.

The impact of a ventilator bundle on preventing ventilator-associated pneumonia: a multicenter study

BACKGROUND

For prevention of ventilator-associated pneumonia (VAP), a bundle approach was applied to patients receiving mechanical ventilation in intensive care units. The incidence of VAP and the preventive efficacy of the VAP bundle were investigated.

METHODS

A quasi-experimental study was conducted in adult intensive care units of 6 university hospitals with similar VAP rates. We implemented the VAP bundle between March 2011 and June 2011, then compared the rate of VAP after implementation of the VAP bundle with the rate in the previous 8 months. Our ventilator bundle included head of bed elevation, peptic ulcer disease prophylaxis, deep venous thrombosis prophylaxis, and oral decontamination with chlorhexidine 0.12%. Continuous aspiration of subglottic secretions was an option.

RESULTS

Implementation of the VAP bundle reduced the VAP rate from a mean of 4.08 cases per 1,000 ventilator-days to 1.16 cases per 1,000 ventilator-days. The incidence density ratio (rate) was 0.28 (95% confidence interval, 0.275-0.292).

CONCLUSIONS

Implementing the appropriate VAP bundle significantly decreased the incidence of VAP in patients with mechanical ventilation.

Tracheal suction by closed system without daily change versus open system

BACKGROUND

Tracheal suctioning costs are higher with a closed tracheal suction system (CTSS) than with an open system (OTSS), due to the need for complete daily change as recommended by the manufacturer. However, is it necessary to change the closed system daily?

OBJECTIVE

To evaluate the tracheal suctioning costs and incidence of ventilator-associated pneumonia (VAP) using closed system without daily change vs OTSS.

DESIGN

Prospective and randomised study.

SETTING

An Intensive Care Unit in a university hospital.

PATIENTS

Patients requiring mechanical ventilation.

INTERVENTIONS

Patients were randomly assigned to CTSS without daily change or OTSS. We used a CTSS that allowed partial or complete change.

MEASUREMENTS AND RESULTS

There were no significant differences between both groups of patients (236 with CTSS and 221 with OTSS) in gender, age, diagnosis, APACHE-II score, mortality, number of aspirations per day, percentage of patients who developed VAP (13.9 vs 14.1%) or the number of ventilator-associated pneumonia per 1000 days of mechanical ventilation (14.1 vs 14.6). There were not significant differences in tracheal suctioning costs per patient/day between CTSS vs OTSS (2.3+/-3.7 vs 2.4+/-0.5 Euros; p=0.96); however, when length of mechanical ventilation was lower than 4 days, the cost was higher with CTSS than with OTSS (7.2+/-4.7 vs 1.9+/-0.6 Euros; p<0.001); and when length of mechanical ventilation was higher than 4days, the cost was lower with CTSS than with OTSS (1.6+/-2.8 vs 2.5+/-0.5 Euros; p<0.001).

CONCLUSION

CTSS without daily change is the optimal option for patients needing tracheal suction longer than 4 days.

Association between implementation of CDC recommendations and ventilator-associated pneumonia at selected US hospitals

BACKGROUND

To assess whether selected recommendations in the Centers for Disease Control and Prevention "Guideline for Prevention of Nosocomial Pneumonia" were being implemented and having an impact on the occurrence of ventilator-associated pneumonia (VAP) at US hospitals, we surveyed hospitals participating in the National Nosocomial Infections Surveillance (NNIS) system.

METHODS

We mailed a questionnaire to the infection control practitioner of each NNIS hospital in 1995 and used data from the NNIS system to calculate annual rates of VAP.

RESULTS

Of the 188 hospitals surveyed, 179 (95%) returned completed questionnaires. Of these, 175 (98%) had implemented the recommended change of mechanical-ventilator breathing circuits at 48-hour or greater intervals. Of 110 hospitals using the hygroscopic condenser-humidifiers or heat-moisture exchangers with ventilators, 102 (93%) changed the hygroscopic condenser-humidifiers or heat-moisture exchangers routinely, and of 98 hospitals using bubbling humidifiers, 96 (98%) used sterile water to fill these humidifiers. Other practices for which the guideline provides no recommendation and their frequency of use by NNIS hospitals include use of hygroscopic condenser-humidifiers or heat-moisture exchangers (110/179 [61%]) and use of bacterial filters in anesthesia machines (128/171 [61%]). There was a significant decrease in the VAP rate from 1987 to 1998.

CONCLUSION

Most NNIS hospitals had implemented selected recommendations in the Centers for Disease Control and Prevention "Guideline for Prevention of Nosocomial Pneumonia" before the final publication of the revised guideline. Further studies are needed to assess the impact of these recommendations on the occurrence of VAP.

Therapy for ventilator-associated pneumonia

Pneumonia is a serious complication of mechanical ventilation. Pneumonia occurs despite the best efforts at prevention. Multiple methods available to prevent ventilator-associated pneumonia are reviewed, and ventilation-associated pneumonia (VAP) is divided into early versus late onset. The authors discuss the organisms associated with each of these situations, the empiric antibiotic choices, and specific issues related to antibiotic therapy such as resistance, pharmcodynamics, tissue penetration, and types of modifications necessary in empiric choice when the cause of VAP is identified.

Suction apparatus and the suctioning procedure: reducing the infection risks

Serious infection has been related to the use of suction apparatus and to the suctioning procedure. Prevention of infection focuses on aseptic technique, handwashing, decontamination and sterilization of apparatus where appropriate. This article considers the infection risks arising from use of suction apparatus, the suctioning procedure and sets out recommendations for infection prevention.

Prolonged and multipatient use of prefilled disposable oxygen humidifier bottles: safety and cost

OBJECTIVES

Multipatient use and prolonged use of prefilled disposable oxygen humidifier bottles (Aquapak 301, Respiratory Care, Inc., Arlington Heights, IL) were evaluated by performing microbiologic monitoring and a cost analysis on bottles used for varying numbers of patients and lengths of time.

METHODS

Humidifiers were hung for a maximum of one month. Monitoring was conducted in 6 different nursing areas. Quantitative cultures were done for aerobes and Legionella. Reusable humidifier bottles also were monitored.

RESULTS

Cultures were obtained from 1,311 disposable and 60 reusable humidifiers. No significant bacterial contamination was detected in the prefilled disposable oxygen humidifier units. Ten percent of the reusable bottles were contaminated by organisms associated with skin flora.

CONCLUSIONS

Multipatient use and increased duration of use of disposable humidifiers result in cost savings without increasing patient risk. Restricted multipatient use of prefilled disposable oxygen humidifier bottles for a period of one month is a safe and cost-efficient practice.

Audit in infection control--data analysis and infections in the intensive care unit

The importance of high standards of infection control practices in intensive care units is widely accepted. Despite this, few objective measures of the efficacy of such practices have been developed. This hampers clinical audit, which is essential if nosocomial infections are to be kept to a minimum. Small sample size, multiple dependent variables, difficulty in matching populations, and the covert effects of confounding factors and bias, all add to the problems of designing meaningful audit programmes in intensive care settings. Nevertheless, useful analysis can be attempted now that appropriate standards and scoring systems are available. Computer systems can simplify data collection, analysis and reporting but they are no substitute for careful preparation and good statistical technique.

Nosocomial pneumonia: epidemiology and infection control

Elderly, debilitated, or critically ill patients are at high risk for hospital acquired or nosocomial respiratory tract infection. Gram-negative bacilli, Staphyloccoccus aureus, and anaerobes colonizing the oropharynx are the most frequent etiologic agents. Colonization of the oropharynx may be related to the patient's age, underlying disease, nutritional status, prior exposure to antibiotics, supine position, and gastric colonization. Nosocomial pathogens may also be acquired from the hands of hospital personnel, contaminated equipment or fluids. The absence of sensitive and specific methods for accurate diagnosis remain a concern. Despite treatment with appropriate antimicrobial therapy, there is a high mortality and morbidity. Measures for the prevention of nosocomial pneumonia should include compliance with infection control principles, appropriate use of antibiotics, proper patient position, and removal of potential sources of cross colonization.

Preventing nosocomial pneumonia: state of the art and perspectives for the 1990s

In the 1980s, nosocomial pneumonia became the second most common nosocomial infection in the United States. Gram-negative bacilli and Staphylococcus aureus were the most frequently isolated bacteria. Methods to improve the diagnostic sensitivity and specificity included transtracheal aspirates and bronchoscopy with protected specimen brush or bronchoalveolar lavage. Multivariate analysis was used to identify independent risk factors for pneumonia and fatality in different subsets of high-risk patients. Gastric pH and colonization were evaluated as risk factors for pneumonia in mechanically ventilated patients. Colonized respiratory therapy equipment and contaminated tubing condensate and in-line medication nebulizers were suggested as possible sources of nosocomial pathogens. Staff education programs, the use of barrier precautions, and selective decontamination of the digestive tract were associated with reduced rates of lower respiratory tract infection. Despite a decade of progress in our understanding of nosocomial pneumonia, progress in the 1990s will undoubtedly include molecular epidemiologic techniques, appropriate application of risk factor data, and the use of new methods for the diagnosis of pneumonia. Prevention strategies should focus on more effective infection control techniques, improved invasive devices/equipment, and the judicious use of antibiotics for treatment and prophylaxis.

Postoperative pneumonia and urinary-tract infection: epidemiology and prevention

Hospital-acquired pneumonias and urinary-tract infections are important causes of morbidity and mortality in surgical patients, and a great deal of effort has been expended on infection control strategies to prevent their occurrence. Prophylactic antibiotics, used either systemically or topically, are not routinely recommended for the prevention of either of these infections. The beneficial effects of these agents are transient, and they are often in association with the acquisition of colonization or infection with resistant bacteria. New approaches for infection control, not involving antibiotic agents, are being developed to lower the infection rates of both hospital-acquired pneumonias and urinary-tract infections to an irreducible minimum.

Nosocomial bacterial pneumonia: an overview

Nosocomial pneumonia accounts for 10% to 20% of all nosocomial infections and represents one of the most serious complications of hospitalization. This review focuses on the etiology, pathogenesis, and prevention of nosocomial pneumonia, with emphasis on infection control procedures to prevent and minimize its occurrence.