Fatality rates for nosocomial pneumonia, particularly VAP, are high.
The primary mission of every health care institution is to provide appropriate, safe, and cost-effective patient care. Therefore, understanding, controlling, and monitoring nosocomial pneumonia, particularly ventilator-associated pneumonia (VAP), are important to health care professionals. VAP can have a major impact on patient care and costs due to its substantial morbidity and mortality. The fatality rates for nosocomial pneumonia in general, and VAP in particular, are high. For nosocomial pneumonia, mortality rates of 20% to 33% have been reported;1-6 in one study,1-6 VAP accounted for 60% of all deaths due to nosocomial infection.1-6 Analyses of pneumonia-associated morbidity have shown that nosocomial pneumonia can prolong stays in the intensive care unit by an average of 4.3 days and hospitalization by 4 to 9 days.7 Given this information, it is no wonder that reducing or alleviating VAP has become a top priority.
Definition and Diagnosis
As early as 1972, Johanson et al8 defined VAP as nosocomial pneumonia in a patient using mechanical ventilatory support (via endotracheal tube or tracheostomy) for 48 hours or more. According to the Centers for Disease Control and Prevention (CDC) Healthcare Infection Control Practices Advisory Committee, nosocomial pneumonias, and especially VAP, are difficult to diagnose. Traditional criteria for diagnosis have been fever, cough, and the development of purulent sputum, in combination with radiographic evidence of a new or progressive pulmonary infiltrate, leukocytosis, a suggestive Gram stain, and the growth of bacteria (in cultures of sputum, tracheal aspirate, pleural fluid, or blood). Although clinical criteria, together with cultures of sputum or tracheal specimens, may be sensitive for bacterial pathogens, they are highly nonspecific, especially in patients with VAP; conversely, blood cultures have a very low sensitivity.7
Because of these problems, in 1992, a group of investigators recommended standardized methods for diagnosing pneumonia in clinical research studies of VAP. These methods involved bronchoscopic techniques: quantitative culture of protected specimen brush specimens, bronchoalveolar lavage (BAL), and protected BAL. The reported sensitivities and specificities have ranged from 60% or 70% to 100%, depending on the tests or diagnostic criteria used for comparison. Because these techniques are invasive, they can cause complications such as hypoxemia, bleeding, or arrhythmia.7 Bronchoscopic examinations are also expensive, adding to the already high expense of VAP.
Project Team and Process
To provide patient care that is appropriate, safe, and cost-effective, an interdisciplinary process-improvement team was formed at St Vincent Hospital, Santa Fe, NM, in 2001 to evaluate methods that might reduce the VAP rate in the critical care unit. The collaborative team was composed of a pulmonologist and an infection-control disease specialist physician; nursing management, education personnel, and staff; respiratory care staff; and the infection-control nurse for the organization. The author served as team leader.
A detailed literature review and analysis evaluated the cost-effectiveness of decreasing the frequency of mechanical ventilator circuit and in-line suction catheter exchanges, existing policies relating to oral care and patient positioning, routine instillation of saline solution during suction, and discontinuing the use of a passive humidification system and implementing an active humidification system. In addition, the team evaluated a recommendation that all medications currently being delivered by in-line nebulizer be delivered by in-line metered-dose inhaler (MDI). The team also discussed establishing monitoring frequency, internal and external benchmarks for VAP, and evaluation criteria for outcomes data. This project and related analyses took place over a 6-month period.
The team established, as its project goals, decreasing the VAP rate below established internal benchmark, modifying existing patient care policies as needed, reverting to existing policies if established internal VAP benchmarks are exceeded, decreasing ventilator days, decreasing operational expenses relating to mechanical ventilation, providing detailed education to bedside practitioners, and achieving a VAP rate that stands at less than the 50th percentile of the CDC National Nosocomial Infections Surveillance (NNIS) benchmark (relative to comparative size and scope of the critical care unit).9
In support of the projects goals, several changes in clinical practice have been proposed. Positioning10 has been changed from minimally elevated to the semi recumbent position; placing the patient flat and supine is to be avoided. The head of the bed is to be raised to an angle of 30° to 45°, unless contraindicated, and the use of a therapeutic bed to provide rotation or vibration is to be considered.
Every 2 hours and additionally as needed, the patients mouth is to be assessed and oral care is to be performed using a suction oral swab. Suction is to be applied to the oropharynx just above the cuff of the endotracheal tube to decrease potential microaspiration of oropharyngeal secretions. Stress ulcer prophylaxis is to be performed using agents that do not alter gastric pH, such as sucralfate.10
Unless a significant desaturation event (to a point 15% or more below the established baseline) takes place, preoxygenation prior to applying suction will be conducted using the mechanical ventilator. Manual resuscitators are to be used only for desaturation events and in situations that require patient transport and/or cardiopulmonary resuscitation. During suction interventions, the instillation of saline should be minimized. Suction is to be applied only when indicated by breath sounds or by the presence of other indicators, such as:
- increased peak inspiratory pressures during volume-control ventilation or decreased tidal volume during pressure-control ventilation;
- visible secretions in the airway;
- the sudden onset of respiratory distress, when airway patency is questioned;
- an increased respiratory rate, sustained coughing, or both;
- suspected aspiration of gastric or upper-airway secretions;
- clinically apparent increased work of breathing;
- deterioration of arterial blood-gas values or pulse oximetry results;
- inability to generate an effective, spontaneous cough; or
- radiographic changes consistent with the retention of pulmonary secretions.
For the delivery of aerosolized medications, the MDI is the method of choice. If handheld nebulizer therapy is ordered, its delivery site is to be relocated to the dry side of the humidifier canister (inspiratory tubing acts as a reservoir).
The frequency with which mechanical ventilator circuits are changed is to be decreased from every 7 days to every 30 days (and as needed,11 based on practitioners assessments or on being visibly soiled or unsightly). In-line suction catheters are to be changed weekly (not daily, as previously required) and as needed12 due to visible soiling, unsightliness, or assessments. Humidification is to be active, with dual heated-wire ventilator circuits, a heater, and a humidification chamber being standard equipment. Use of heat/moisture exchangers is to be limited to patient-transport situations (which include CT and MRI scanning).
The teams goals, suggested clinical-practice changes, and monitoring and outcomes criteria were next presented, in proposal format, to the infection-control committee. This step was taken to garner their evaluation and, ultimately, their support. The institutions risk manager was also consulted to discuss any concerns relating to deviation from manufacturers recommendations for circuit and suction-catheter exchange frequency. The committee and risk manager supported the proposal, and the project moved forward.
Practitioner education remains the cornerstone of an effective infection-control program. Therefore, a substantial amount of time and effort went into developing and implementing the education program for this project, which emphasized the importance of good hand-washing techniques, the changes made to clinical practice, and the reporting of monitoring and outcomes data. From an infection-control standpoint, decreasing the VAP rate in the critical care area was deemed a very high priority. Subsequently, information concerning the project was communicated to caregivers using storyboards and shift-change or impromptu education sessions that conveyed the project’s goals and objectives before implementation.
Monitoring and Results
Project monitoring was conducted on a monthly basis and reported quarterly. The performance-improvement team met monthly to evaluate data and monitor progress. Data evaluated during the monthly sessions concerned ventilator days per quarter, VAP cases per quarter, quarterly infection rates, comparison to the internal VAP benchmark and the CDC/NNIS median rate, and respiratory care supply costs (see table, page 34).
The internal benchmark for VAP was 14.14 per 1,000 device days. This median was calculated based on the two previous years reported VAP data. Median ventilator days for the same period were 284. In addition, the data analyzed for the quarter prior to implementing the changes in clinical practice demonstrated a VAP rate of 15.6 per 1,000 device days and a total of 320 ventilator days. This substantially exceeded the established benchmark and sparked additional support for the project. Subsequently, the project was successfully implemented on schedule. All data that follow represent information obtained during a 6-month evaluation period.
During the quarter prior to project implementation, 320 ventilator days and five VAP infections made the quarterly VAP rate 15.6 per 1,000. This exceeded the internal benchmark by 10.3% and placed the critical care unit in the 90th percentile, in comparison with NNIS data sources.
During the next quarter, the project was implemented. At the same time, the team determined that the NNIS median rate required adjustment downward by 0.2, based on scope of practice and case mix. The number of ventilator days rose to 426, and VAP cases decreased to four. The overall VAP rate for the quarter decreased to 9.39 per 1,000. This was 33.61% below the established benchmark and between the 50th and 75th NNIS percentile. The supply cost per ventilator day decreased by 43% as compared to the same quarter in the previous year.
During the final quarter of project evaluation, the number of ventilator days rose to 510 and the number of VAP cases increased to seven. This represented a VAP rate of 13.73 per 1,000 device days or -0.42 (-2.95%) reduction below the benchmark. In comparison to the NNIS data, the overall ranking rose back into the 90th percentile. The supply cost per ventilator day decreased by 28% as compared to the same quarter in the previous year. Since there was a rise in the VAP rate for the period, even though the internal benchmark was not exceeded, refresher caregiver education sessions were provided.
The project was successful in decreasing VAP rates 18.2% below benchmark while decreasing operational expenses an average of 35%. Comparison of VAP rate to project implementation demonstrates an overall reduction of 25.9% (VAP rate of 15.6 vs 11.56, P = < 0.03). This was accomplished while continuing to provide high-quality patient care. All of the protocol goals have been accomplished, with the exception of reaching the 50% percentile or less in the NNIS VAP rates. While this will remain an ultimate goal of the project, a significant impact was still made on patient care. After presentation of these results and their review by the institutions infection-control committee, all project-related proposed changes in practice were validated and made the standard of practice for the critical care unit.
In todays health care environment, and particularly in the critical care unit, VAP is associated with increased mortality and morbidity, expensive and prolonged care, and diminished outcomesand it occurs with entirely too much regularity. There are many low-risk interventions that can potentially reduce its incidence. While additional research is needed to confirm the benefit of several practices that might affect VAP rates, much can be done now to enhance patient care through careful scrutiny of the existing literature, use of the interdisciplinary and performance-improvement models, and provision of consistent caregiver education and reinforcement.
Gary J. Hospodar, MAOM, RRT-NPS, is chief operating officer, Southwest Healthcare Consultants, Placitas, NM. A version of this article was presented at the AARC International Conference in Tampa, Fla, on October 10, 2002.
1. Craven DE, Kunches LM, Lichtenberg DA, et al. Nosocomial infection and fatality in medical and surgical intensive care units. Arch Intern Med. 1988; 148:1161-1168.
2. Celis R, Torres A, Gatell JM, et al. Nosocomial pneumonia: a multivariate analysis of risk and prognosis. Chest. 1988;93:318-324.
3. Kollef MH. Ventilator-associated pneumonia. JAMA. 1993;270:1965-1970.
4. Craig CP, Connelly S. Effect of intensive care unit nosocomial pneumonia on duration of stay and mortality. Am J Infect Control. 1984;4:233-238.
5. Fagon JY, Chastre J, Hance AJ, Montravers P, Novara A, Gibert C. Nosocomial pneumonia in ventilated patients: a cohort study evaluating attributable mortality and hospital stay. Am J Med. 1993;94:281-288.
6. Leu HS, Kaiser DL, Mori M, Woolson RF, Wenzel RP. Hospital-acquired pneumonia: attributable mortality and morbidity. Am J Epidemiol. 1989;129:1258-1267.
7. Centers for Disease Control and Prevention Healthcare Infection Control Practices Advisory Committee. Guideline for prevention of healthcare-associated pneumonia [draft]. Available at: http://www.cdc.gov/ncidod/hip/pneumonia/DraftPneu_Guide_2002acc.pdf. Accessed May 25, 2003.
8. Johanson WG Jr, Pierce AK, Sanford JP, Thomas GD. Nosocomial respiratory infections with gram-negative bacilli. The significance of colonization of the respiratory tract. Ann Intern Med. 1972;77:701-706.
9. National Nosocomial Infections Surveillance (NNIS) System Report, Data Summary from January 1992-June 2001, Issued August 2001. Division of Healthcare Quality Promotion, National Center for Infectious Diseases, Atlanta. Available at: http://www.apic.org/pdf/nnisreport200212.pdf. Accessed May 25, 2003.
10. Shojania KG, Duncan BW, McDonald KM, et al. Making Health Care Safer: A Critical Analysis of Patient Safety Practices. Evidence Report/Technology Assessment No. 43. San Francisco: UCSF-Stanford Evidence-based Practice Center; 2001.
11. Kollef MH, Shapiro SD, Fraser VJ, et al. Mechanical ventilation with or without 7-day circuit changes. A randomized controlled trial. Ann Intern Med. 1995;123:168-174.
12. Kollef MH, Prentice D, Shapiro SD, et al. Mechanical ventilation with or without daily changes of in-line suction catheters. Am J Respir Crit Care Med. 1997;156:466-472.