Bacterial contamination of pulmonary artery catheters

Survey of Intensive Care Nurses’ Knowledge Relating to the Pulmonary Artery Catheter

In 2003 there was an increase in the use of pulmonary artery catheters in Australia from 12,000 to 16,000 units in intensive care and peri-operative care. This survey of intensive care nurses in five intensive care units in Queensland addressed knowledge of use, safety and complications of the pulmonary artery catheter, using a previously validated 31 question multiple choice survey.

One hundred and thirty-nine questionnaires were completed, a response rate of 46%. The mean score was 13.3, standard deviation ±4.2 out of a total of 31 (42.8% correct). The range was 4 to 25. Scores were significantly higher in those participants with more ICU experience, higher nursing grade, a higher self-assessed level of knowledge and greater frequency of PAC supervision. There was no significant correlation between total score and hospital- or university-based education, or total score and public or private hospital participants. Fifty-one per cent were unable to correctly identify the significant pressure change as the catheter is advanced from the right ventricle to the pulmonary artery.

Pulmonary Artery Catheters: An Update

Pulmonary artery (PA) catheters are widely used in the care of the critically ill. Numerous catheter designs are available, and the list of indications for their use is con stantly expanding. Extensive physiological data are sup plied by catheters. Right atrial, right ventricular, PA, and PA wedge pressure waveforms, as well as cardiac output and several derived parameters (e.g., systemic vascular resistance, pulmonary vascular resistance) are easily measured. Clinical application of these data may aid in diagnosis and management of acutely ill patients. Physi cians using catheters need to be aware of the numerous complications associated with their use. Scrupulous at tention to insertion and maintenance techniques will minimize the incidence of many of these complications. The undefined risk/benefit ratio of PA catheterization has caused controversy among physicians. Prospective studies to define better the risks versus benefits of PA catheters are currently being planned. Physicians using PA catheters should recognize that the catheters have no direct therapeutic benefit and that PA catheterization should neither replace bedside clinical evaluation nor delay treatment of the patient.

The pulmonary artery catheter: uses and controversies

The pulmonary artery catheter is an invasive hemodynamic monitor that can provide diagnostic information in situations where history and physical examination are inconclusive. Assisting the physician in therapeutic decisions has added to its clinical value. Understanding the information it provides and making thoughtful therapeutic decisions lie at the core of its use. Despite its use, the PA catheter has been the center of great controversy. Clearly the paucity of prospective randomized trials proving its efficacy is alarming. The inability of physicians to interpret the provided data properly is also unacceptable. Although instituting a moratorium on its use may be extreme, limiting its use to approved indications seems more appropriate. In the future, ready availability of other less invasive methods such as echocardiography may allow clinicians to become less reliant on the PA catheter. Until then, clinicians would be served best by comprehending the intricacies and the limitations of this sophisticated instrument.

Specific problems of arterial, Swan-Ganz, and hemodialysis catheters

In our experience, the incidence and pathogenesis of colonization may vary in different types of catheters. Arterial, Swan-Ganz, and hemodialysis catheters are good examples of this problem. This observation has implications for diagnosis, and the best method for each type of catheter may not be the same. In our opinion, laboratory diagnosis in daily practice should be limited to external surface cultures of the tip of intravascular catheters. Intraluminal cultures should be limited to research purposes, except in catheters used for parenteral nutrition or hemodialysis. In this case, the intradermal segment gives more sensitive information. Sensitivity in diagnosing pulmonary artery colonization can be improved by evaluating both the tip and intradermal segments. In presence of an indwelling introducer the intradermal segment should be replaced by the introducer tip.

Nosocomial blood-borne infection secondary to intravascular devices

A total of 143 patients with 159 episodes of intravascular device, blood-borne infection were studied. All infections were confirmed by the same organism being recovered from blood culture and by semiquantitative culture of the catheter tip. Sites of infection included the peripheral venous line (n = 72), central catheter (n = 49), arterial line (n = 18), subclavian dialysis catheter (n = 12), Swan-Ganz catheter (n = 4), Broviac catheter (n = 3), and transvenous pacemaker wires (n = 1). Staphylococcus aureus (n = 78) and Staphylococcus epidermidis (n = 33) predominated as pathogens. Excessive length of catheterization was implicated as directly responsible for this complication in patients with peripheral intravenous and arterial lines. Nosocomial staphylococcal bacteremia must be considered secondary to an indwelling intravascular device until proven otherwise. Appropriate therapy requires removal of the catheters, excision of the vein if suppuration or persistent bacteremia is identified, and specific antibiotic therapy.

Infection of pulmonary artery catheters. Epidemiologic characteristics and multivariate analysis of risk factors

Sixty-nine consecutive pulmonary artery catheters (PACs) were prospectively studied in a medical-surgical intensive care unit. Fifteen (21.7 percent) and two (2.9 percent) of the PACs were associated with colonization and bacteremia, respectively. These data represent an incidence of 4.98 and 0.66 episodes per 100 catheterization-days, respectively. Coagulase-negative staphylococci were the most common isolates. The source of the colonizing microorganism was the skin in 56 percent of cases, hubs in 28 percent, and unknown in 16 percent. From multivariate analysis, only more than 5 days of catheterization was significantly associated with a greater risk of colonization. Antimicrobial use was associated with negative cultures. The most useful method to diagnose colonization was the examination of both tip and intradermal segments. In addition, we suggest associate hub cultures when catheter-related bacteremia is suspected. These data may be useful in improving efficacy in the diagnosis and prevention of PAC-related infection.

Catheter related infection. A plea for consensus with review and guidelines

Although there has been a proliferation of catheter related infection literature there is still little consensus regarding infection statistics and optimal catheter management techniques. This paper analyses the various factors that have contributed to these inconsistencies and thereby attempts to provide a standardised framework for future research and communication on the subject. An attempt has also been made from available data to provide management guidelines that are practicable in the intensive care environment.

Biofilms on right heart flow-directed catheters

This study was designed to detect biofilm and bacteria on right heart flow-directed catheters using scanning electron microscopy and culture following scraping and dispersion of biofilm by sonication. We examined 20 consecutive catheters removed from 18 critically ill patients, an average of 2.6 days after insertion. On scanning electron microscopy, all catheters were found to be covered by a biofilm, with bacteria visible on 50 percent of them. Cultures of specimens from 40 percent of the catheters grew skin organisms (Staphylococcus warneri, Diphtheroid), anaerobes (Propionibacterium), and other potential pathogens (Proteus vulgaris, Enterobacter cloacae). Combination of the two techniques produced a bacterial detection rate of 75 percent. This study demonstrates that the presence of biofilm with bacterial adherence is common on right heart flow-directed catheters. The phenomenon could play a significant role in endogenous infection in critically ill patients.

Complications of right heart catheterization. A prospective autopsy study

The purpose of this study was to characterize the type and prevalence of abnormalities associated with right heart catheterization. We performed detailed post-mortem examinations of 32 consecutive patients brought to autopsy with a right heart catheter in the pulmonary artery. Thrombosis (17 patients, 53 percent), hemorrhagic lesions (25 patients, 78 percent), and intimal fibrin deposition (21 patients, 66 percent) were found at sites along the entire path of the catheter. Twenty-nine patients (91 percent) had either thrombosis, hemorrhage or both. While the superior vena cava was the most common site for all lesions, seven patients had thrombosis involving the chambers and valves of the heart and four had thrombosis involving the pulmonary artery. The incidence of thrombosis was significantly higher after 36 hours of catheterization (p less than 0.05). All five patients with thromboemboli in the more proximal pulmonary arteries had catheter-related thrombosis. We conclude that there is a high prevalence of thrombotic and hemorrhagic lesions in patients dying with pulmonary catheters in place; that the risk of thrombotic complications increases with duration of catheterization; and that patients with catheter-related thrombosis are at increased risk of thromboemboli to the proximal pulmonary arteries.

Pulmonary artery catheter infections. A prospective study

Despite the widespread use of the Swan-Ganz pulmonary artery catheter, the incidence of catheter tip infection is not well-established. One-hundred and seventy catheter insertions in 113 patients were examined in this prospective study. Using a semiquantitative culture technique, the incidence of positive catheter tip cultures was 5.8%. No significant risk factors for catheter infection were identified, although there was a trend toward more frequent infection in patients not receiving antibiotics (p less than 0.06). Catheter tip infection appeared to result most frequently from a distant focus of infection. Although the overall incidence of positive blood cultures was significantly higher in the positive vs. negative catheter tip groups (37.9% vs. 10.6%, p less than 0.001), blood cultures were generally not a reliable guide to the presence of a catheter tip infection. We conclude that catheter infection can be contained at an acceptable level by following a reasonable protocol for catheter management.

Cardiovascular-pulmonary monitoring in the intensive care unit (Part 2)

Proliferation of technology in the ICU likely will continue at a rapid pace. This presents a strong challenge to the clinician's task of "above all, do not harm." While invasive techniques carry obvious direct risks, both invasive and noninvasive monitoring present a more subtle threat. Pitfalls in the acquisition and interpretation of data must be recognized before appropriate therapeutic decisions can be made. Advanced monitoring devices and techniques must supplement and not supplant clinical assessment.