By Kelly M. Pyrek, Editor in Chief, Infection Control Today magazine

The intensive care unit patient is susceptible to a number of common healthcare-acquired infections (HAIs), including ventilator-associated pneumonia (VAP), catheter-related bloodstream infections (CLABSIs), catheter-associated urinary tract infections (CAUTIs), and Clostridium difficile infections (CDIs), among others. There are numerous predisposing factors to take into consideration, say Dhillon, et al. in ICU Infection Control and Preventive Measures, who add, "Critically ill patients in the ICU are more likely to have invasive catheters, devices, or undergo surgical treatments that disrupt the skin barrier. Burn victims also develop HAIs as a result of the physical barrier disruption. The ability to clear infections may further be reduced by underlying chronic diseases, thus increasing the risk of HAI. Other significant risk factors include urinary catheter >10 days, ICU confinement >3 days, presence of intracranial pressure monitor/arterial line/central venous catheter, and shock." 
The criticality of the typical ICU patient lends itself to opportunistic pathogens and infections, so great care must be taken to curb and eliminate the chances for disease transmission in this unit. As Osman MF and Askari R observe in Infection Control in the Intensive Care Unit, "It is critical for healthcare personnel to recognise and appreciate the detrimental impact of intensive care unit (ICU)-acquired infections. The economic, clinical, and social expenses to patients and hospitals are overwhelming."

The metrics bear this out; in the U.S., more than 5 million patients are admitted to ICUs annually. Although ICUs constitute less than 10 percent of total beds in most hospitals, more than 20 percent of all nosocomial infections are acquired in ICUs. ICU-acquired infections account for substantial morbidity, mortality, and hospital costs. Infections and sepsis are the leading causes of death in non-cardiac ICUs and account for 40 percent of all ICU expenditures. As Osman and Askari (2014) emphasise, "As the number of ICU beds increases, the proportion of ICU infections is likely to increase, putting more strains on healthcare costs. Patients in critical care settings are more susceptible to nosocomial infections. Overall, compared with the general hospital population, patients in ICUs have more chronic comorbid illnesses and more severe acute physiologic derangements."

The most recent National and State Healthcare-Associated Infections Progress Report (US)—which includes 2014 data, published in 2016—describes significant reductions reported at the national level in 2014 for nearly all infections when compared to the baseline data. CLABSI is among the HAIs that show the greatest reduction, while some progress is shown in reducing hospital-onset MRSA bacteremia and hospital-onset C. difficile infections. Let's take a closer look at the HAIs of great concern in the ICU.

Ventilator-Associated Pneumonia
Hospital-acquired pneumonia (HAP) is defined as pneumonia that occurs at least 48 hours after admission to the hospital. VAP—the leading cause of mortality from ICU-acquired infections—is a type of HAP that develops more than 48 hours after endotracheal intubation, which increases the risk of pneumonia 6- to 21-fold, according to various studies. Studies have shown that patients with VAP are twice as likely to die compared with those without VAP, with a crude mortality rate that exceeds 30 percent if a high-risk pathogen is involved. Several reports have shown that patients who develop VAP have an increase in ICU stay of 4.3 to 13 extra days and an increase in costs with each case of VAP ($12,000 to $40,000).
A risk factors review by Safdar and colleagues revealed that postsurgical patients, presence of multiple organ failure, age greater than 60 years, supine patient positioning, decreased gastric pH, cardiopulmonary resuscitation, continuous sedation, reintubation, presence of nasogastric tube, enteral feeding, sinusitis, and patients transported out of the ICU had increased risk of developing VAP.
As Osman and Askari (2014) note, "Owing to the high morbidity and mortality and economic impact of this condition, the implementation of preventive measures is paramount in the care of mechanically ventilated patients. There is clear evidence that these measures decrease the incidence of VAP and improve outcomes in ICUs. A multidisciplinary approach, continued education, and ventilator protocols ensure the implementation and compliance with these measures."

CLABSI
Studies have demonstrated that the incidence of CLABSIs varies considerably by catheter-related factors (including location of catheter insertion; catheter insertion technique; long duration of catheterisation; submaximal vs. maximal barrier precautions usage during insertion; catheter-site care; and catheter material type) and patient-related factors (including previous bloodstream infection; loss of skin integrity; immune deficiency; and chronic illness).

Proper compliance with evidence-based interventions is necessary in the prevention of CLABSIs. As Osman and Askari (2014) emphasise, "It is critical to observe proper hand hygiene procedures either by washing hands with conventional antiseptic-containing soap and water or with waterless alcohol-based gels or foams. This should be maintained before and after palpating catheter insertion sites as well as before and after inserting, replacing, accessing, repairing the catheter, or changing the dressing. Use an all-inclusive catheter cart or kit. Use maximal sterile barrier precautions during CVC insertion, including a full-body drape over the patient, mask, cap, sterile gloves, and gown. Use a 2 percent chlorhexidine-based antiseptic for skin preparation in patients older than 2 months…Disinfect catheter hubs, needleless connectors, and injection ports before accessing the catheter. Frequently assess the need to keep intravascular catheters and promptly remove any catheter that is no longer essential…Last but not least, it is essential to educate and periodically assess adherence of all ICU staff with the indications for intravascular catheter use, proper procedures for the insertion and maintenance of intravascular catheters, and appropriate infection control measures to prevent intravascular catheter-related infections."

CAUTI
Studies show that nosocomial urinary tract infections (UTIs) account for up to 40 percent of infections in hospitals and 23 percent of healthcare-acquired infections in ICUs. CAUTIs have been associated with a three-fold increased risk for mortality in hospital-based studies, with estimates of more than 50,000 excess deaths occurring per year in the United States as a result of these infections. CAUTIs result in as much as $131 million in excess direct medical costs across the US annually. 

Duration of catheterisation is the most important risk factor for CAUTIs, as up to 95 percent of UTIs in ICUs are associated with an indwelling urinary catheter. According to Osman and Askari (2014), "Bacteruria, the precursor to CAUTI, develops quickly at an average daily rate of 3 percent to 10 percent per day of catheterisation. Almost 26 percent of patients with a catheter in place for 2 to 10 days develop bacteruria, and virtually all patients catheterised for 1 month develop bacteruria."

CAUTI prevention strategies include avoiding the insertion of indwelling urinary catheters when possible, and the most effective strategy for CAUTI prevention is limitation or avoidance of catheterisation as appropriate. Studies indicate that checklists, daily plans, nurse-based interventions and electronic reminders were all found effective at reducing the duration of catheterisation. Proper techniques for insertion and maintenance of catheters are essential preventive measures; all urinary catheters should be inserted by a trained healthcare professional using aseptic technique.

Indwelling devices and the transfer of pathogenic organisms from healthcare personnel to patients are among some of the biggest threats in the ICU, says Reza Askari, MD, FACS, of the Division of Trauma, Burns and Surgical Critical Care in the Department of Surgery at Brigham and Women’s Hospital/Harvard Medical School in Boston. In terms of pathogens of particular concern in the ICU, he notes, "Any pathogen is of great concern; however, we tend to worry most about multi-drug-resistant organisms —MRSA, VRE and MDR Gram-negative Bacilli, especially the latter given the lack of new pharmaceutical agents to treat these infections."

"The ICU is an environment housing our sickest patients and sometimes these patients have multiple infections especially those with drug-resistant organisms," says Askari. "Therefore, it is imperative that we use a multi-modal approach to prevent HAI which increases the morbidity and mortality of our patients."

System-based programmes can provide a framework for improved staff education and compliance with evidence-based practices, Osman and Askari (2014) point out. "Checklists and interventions targeting communication efficiency among all ICU staff and daily multidisciplinary rounds with discussions of mechanical ventilator, CVC, and urinary catheter protocols can significantly decrease the rate of VAP and CLABSI, with a downward trend in CAUTI. In addition, adequate nursing and support staff is necessary for infection control.”

Other strategies include hand hygiene, which is vital to patient care in ICUs and is extremely cost-effective. As Osman and Askari (2014) emphasise, "Continuous encouragement and monitoring with reinforcement of hand hygiene policies are important to maintain and improve compliance rates and reduce the ICU-acquired infection rate." Patient screening for MDROs also can be helpful, as patients newly admitted to an ICU who are colonised with multidrug-resistant pathogens are a constant reservoir for transmission and subsequent infection.

Once colonised patients can be identified, isolation measures and contact precautions can be put into place, thus ensuring gown and glove use on entering rooms of patients colonised with antibiotic-resistant pathogens. Taking precautionary measures one step further, Osman and Askari (2014) point to studies in which the use of 2 percent chlorhexidine cloths to daily bathe ICU patients has been shown an effective method of decreasing both hospital-acquired infections (including bloodstream infections, SSIs, and VAP) and colonisation with drug-resistant organisms. 

It cannot be overstated that environmental hygiene is key to preventing HAI transmission in the ICU. Clinical workstations within hospital ICUs may get overlooked during routine cleanings and could therefore harbour more dangerous bacteria than regularly cleaned objects in patient areas, according to Whiteley, et al. (2015). Researchers from Western Sydney University in Australia conducted a pilot study using three different sampling methods in a busy intensive care unit (ICU) in an attempt to discover if and where multidrug-resistant organisms (MDROs) might still be lurking in spite of routine environmental cleaning. Investigators traced the steps of healthcare workers in between their workstations and patient bedsides and sampled commonly touched objects along the way for MDROs. Nine of 13 confirmed MDROs from any area came from clinical workstations (on chairs, clipboards, keyboards, telephones, and a computer mouse).

As a secondary finding of the study, combined ATP testing on environmental surfaces was more than seven times as likely to positively identify MDROs as microbial swabbing (33.3 percent vs 4.3 percent.). ATP testing is a process of rapidly measuring actively growing microorganisms through detection of adenosine triphosphate (ATP) — a marker of bio-contamination.

"In this pilot study, we found that many of the high touch objects from which MDROs were recovered were not items included in cleaning protocols," state the study authors. "The findings of this study suggest the need to review the hygiene standards adopted in the clinical workspace, away from the immediate patient zones in busy ICUs, and indicate that ATP testing may help identify high touch objects with less than optimal cleanliness."

Staffing and facility design also can contribute to the general hygiene levels in the ICU, as Dhillon, et al. note: "Adequate staffing is necessary to allow patient care to be performed in a manner that offers high level of compliance. If an ICU is understaffed, this may not only diminish basic hygienic practices, but also allow for the development of resistant organisms to spread. Intensive care units should be architecturally constructed in a low traffic flow design that allows for appropriate space to perform daily operations. Materials and surfaces should be easy to clean with nearby sinks to prevent bacterial colonisation."  

Osman and Askari (2014) say that "The ICU environment plays an important role in exposing patients to various pathogenic organisms. These organisms may be found almost anywhere: on the hands of caretakers, on laboratory coats, on knobs of doors, on keyboards, or in the structure and environment of the room itself, increasing the chances of acquiring infections. Measures to decrease the environmental burden of pathogens and subsequently lower the rates of hospital-acquired infections are being heavily studied. Still, experimental techniques for environmental cleansing include UV light sterilisation lamps and hydrogen peroxide vapour decontamination devices, which might contribute to future attempts at reducing colonisation pressure. Combining environmental cleaning with hand hygiene educational campaign can significantly decrease both environmental and hand contamination rates."

As for the future, Askari says the issue of cost is frequently overlooked. "In our ICU, when we have an outbreak of multidrug-resistant Gram negatives, we undertook several methods to help control this. However, people often forget the costs associated with these interventions. We need to think of cost-conscious yet effective means of controlling ICU infections. I think the focus should continue to be on the multi-modal approach but should include the importance of environmental hygiene as well." 

Editor’s note: Used with permission from Infection Control Today, an Informa Life Sciences Publication.