Management of bacterial complications in critically ill patients: surgical wound and catheter-related infections

The occurrence of surgical wound infections and/or bacteremia associated with central venous catheter use are of growing concern to all physicians who treat critically ill patients. The physician must be aware that some patients have an even greater risk for infection, such as those with multiple risk factors, those who are on central lines, or those patients who undergo multiple invasive diagnostic or therapeutic procedures. The emergence of resistant pathogens, particularly Gram-positive pathogens, is an important factor in the morbidity and mortality of hospitalized patients. In the face of this growing resistance among target organisms, the selection of the correct antimicrobial and nonpharmacologic interventions, based on correct identification and susceptibility test data, has become increasingly challenging. Methicillin-resistant Staphylococcus aureus and, more recently, glycopeptide-resistant enterococci and staphylococci represent a significant danger to the patient. As a consequence, earlier and more precise identification of the pathogens most frequently associated with infection is essential. The role of exacting surgical technique, infection control measures, and the appropriate use of prophylactic and therapeutic antibiotics cannot be overestimated in helping to reduce potential morbidity and mortality associated with severe surgical infection. The development of new antibiotics may help treat the difficult cases attributable to resistant Gram-positive bacteria.

Postoperative infections in the age of drug-resistant gram-positive bacteria

Postoperative infection is a significant cause of surgical morbidity and mortality. The risk of infection after surgery depends on a number of factors, including the type and length of the surgical procedure; the age, underlying conditions, and previous history of the patient; the skill of the surgeon; the diligence with which infection control procedures are applied; and the type and timing of preoperative antibiotic prophylaxis. Methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci, now implicated in many postoperative infections, have been joined most recently by strains of S. aureus that show intermediate levels of resistance to vancomycin. Postoperative infections caused by drug-resistant pathogens are more difficult to treat and are associated with a higher morbidity and mortality. New antibiotics that are effective against drug-resistant pathogens are urgently needed, as is renewed dedication to the prevention of postoperative infection and to the use of the principles of infection control.

Evaluation of the protective value of hospital gowns against blood strike-through and methicillin-resistant Staphylococcus aureus penetration

BACKGROUND

Hospital gowns protect patients and health care workers from exposure to blood and other infectious materials. Previous studies have shown that certain gowns do allow blood strike-through. Because of worldwide increases in the incidence of Staphylococcus aureus infections, especially with methicillin-resistant strains, there is now increased concern regarding bacterial transmission through gowns.

METHODS

This study evaluated six gown types used in hospitals (one disposable cover or isolation gown, three disposable operating room gowns, and new and washed reusable operating room gowns). Gowns were evaluated for dry spore and S. aureus filtration efficiencies and were subjected to 20 time-pressure combinations with methicillin-resistant S. aureus-spiked blood (10(4)/ml) to evaluate blood strike-through and passage of methicillin-resistant S. aureus.

RESULTS

Blood strike-through was lowest with disposable operating room gowns 1 and 2 (polypropylene). Disposable operating room gown 3 (polyester-wood pulp) showed the greatest strike-through and overall passage of methicillin-resistant S. aureus. Operating room gowns 1 and 2 showed minimal bacterial passage, whereas the disposable cover (polypropylene) only allowed passage at pressures greater than 1 psi. Bacterial filtration efficiency testing showed operating room gowns 1 and 2 to be the most protective; operating room gown 3 and both reusable (cotton) gowns were the least protective. Dry spore passage was greatest for reusable gowns.

CONCLUSION

Different hospital gowns offer varying degrees of protection against fluid strike-through or bacterial passage. Gowns therefore should be chosen according to the task performed and conditions encountered.

Multicenter, randomized study comparing levofloxacin and ciprofloxacin for uncomplicated skin and skin structure infections

BACKGROUND

The fluoroquinolone, levofloxacin, is active against most common pathogens in skin and skin structure infections.

METHODS

The efficacy, tolerability, and safety of levofloxacin and ciprofloxacin were compared in a randomized, open-label, multicenter trial of patients with uncomplicated skin and skin structure infections. Of 469 patients treated, 231 received levofloxacin (500 mg qd) and 238 were given ciprofloxacin (500 mg bid).

RESULTS

Overall clinical success rates (cured plus improved) for levofloxacin and ciprofloxacin were 98% and 94%, respectively (95% confidence interval [CI], -7.7, 0.7). Overall microbiologic eradication rates by patient were 98% in the levofloxacin group and 89% in the ciprofloxacin group (95% CI, -14.5, -2.7), whereas eradication rates by pathogen were 98% and 90%, respectively (95% CI, -12.6, -3.7). The eradication rate for Staphylococcus aureus was 100% in the levofloxacin group and 87% in the ciprofloxacin group (95% CI, -20.2, -5.1). Treatment-emergent adverse events were comparable, with drug-related adverse events reported in 6% of levofloxacin patients and 5% of ciprofloxacin patients.

CONCLUSIONS

Levofloxacin is as effective and safe as ciprofloxacin in the treatment of uncomplicated skin and skin structure infections.

Current practices of preoperative bowel preparation among North American colorectal surgeons

In North America, the rate of infections following colorectal surgery decreased after the introduction of oral antibiotic bowel preparation against colonic microflora. Eight hundred eight board-certified colorectal surgeons were surveyed for their current bowel preparation practices before elective procedures. The 471 responders (58%) all use mechanical preparation: oral polyethylene glycol solution (70.9% of the respondents), oral sodium phosphate solution with or without bisacodyl (28.4%), and "traditional" methods of dietary restriction, cathartics, and enemas (28.4%). Most surgeons (86.5%) add oral and parenteral antibiotics to the regimen; 11.5% add only parenteral antibiotics, 1.1% add only oral antibiotics, and 0.9% add no antibiotics. Generally (77.8% of cases), oral neomycin and erythromycin or metronidazole are combined with a perioperative parenteral antibiotic. Most individuals start the preparation as outpatients the day before surgery, and the parenteral drugs are added to the regimen 1-2 hours before the procedure. The use of outpatient bowel preparation is increasing; however, patient selection is critical, and education is needed to reduce the rate of complications.

Surgical infections: prevention and treatment--1965 to 1995

During the 30 year period from 1965-1995, significant advances have been made in the prevention, diagnosis, and management of surgical infections. To a great degree these advances have been provided by surgeons who developed a primary interest in this area. The Surgical Infection Society (SIS) was established in 1980 for surgeons and other physicians and scientists in order to better coordinate efforts in education and research concerning the infected surgical patient. The most significant of these advances were initially the accurate microbiologic definition of the human endogenous microflora in health and disease. Improvements in the techniques utilized to isolate and identity anaerobic microorganisms were of paramount importance. These lead to improvements in the choice of antibiotic agents for prophylaxis and treatment which resulted in improved clinical results. Most recently, emphasis has been placed on the perioperative identification of the high-risk patient who is more likely to develop infection in the postoperative period. By separating high-risk from low-risk patients in each operative procedure, rather than assuming their risk based on the traditional classification of surgical procedure, a more rationale plan of prospective alterations of treatment can be offered.

Meropenem versus tobramycin plus clindamycin for treatment of intraabdominal infections: results of a prospective, randomized, double-blind clinical trial

The efficacy of meropenem was compared to that of the combination of tobramycin plus clindamycin (T/C) in a multiinstitutional clinical trial of treatment for patients suffering intraabdominal infection. Among the 177 patients enrolled and randomized, 127 were clinically evaluable and 86 were microbiologically evaluable. Analysis of data on an intent-to-treat basis for all randomized patients and on the basis of a successful outcome (absence of any infection) for clinically evaluable patients failed to detect any difference in efficacy between the two treatments. Infection was cleared in 92% of meropenem- and 89% of T/C-treated clinically evaluable patients. Eradication of pathogens also was similar in the two treatment groups. Overall, adverse drug experiences were comparable between the two treatment groups, with the exception of an increase in serum creatinine level (which occurred more frequently in patients receiving T/C). Meropenem appears to be efficacious for the treatment of intraabdominal infections.

Determination of surgeon-generated gown pressures during various surgical procedures in the operating room

BACKGROUND

Patients' blood or other potentially infectious body fluids frequently pass through surgeons' gowns in the operating room. These fluids are absorbed by the scrub suit and can directly contaminate the surgeons' skin. Protective barriers remain an important method of exposure control for many blood-borne pathogens. The efficacy of surgical gowns in preventing this passage or strikethrough has therefore become the focus of much attention. Limited data are available concerning the magnitude and duration of pressure against surgeons' gowns.

METHODS

A 32-sensor mat placed in the abdominal area was used to obtain pressure data for 15 surgeons of both sexes performing 20 procedures.

RESULTS

The percentage of time any pressure was detected varied from 0% during knee reconstruction to 97.4% for excision of a stomach mass. In 16 procedures, more than 87.8% of pressure contacts were 2 N/cm2 (2.9 psi or less); in addition, more than 80% of the contacts were 15 seconds or less during 13 of the procedures. No correlation was found between the amount of pressure and sex of the surgeon, surgical service, or length of the procedure.

CONCLUSIONS

Because pressure is related to the type of procedure, gowns should be chosen to afford protection against fluid strikethrough for the pressures and blood loss anticipated.

Surgical antibiotic prophylaxis

Improvements in antibiotic prophylaxis, including the timing of initial administration, appropriate choice of antibiotic agents, and the limiting of the duration of administration, have more clearly defined the value of this technique in many clinical surgical settings. Studies of antibiotic prophylaxis designed during the next decade should strongly consider individual patient risk factors when new antibiotic agents are tested or administration techniques are refined. A concentrated effort should be made in areas of clinical surgery in which the value of antibiotic prophylaxis has not been proven. When in doubt, it appears that a one-dose systemic regimen of an appropriately chosen cephalosporin given during the immediate preoperative period is safe and the indicated practice.

Meropenem versus imipenem/cilastatin in the treatment of hospitalized patients with skin and soft tissue infections

Meropenem is a new carbapenem antibiotic shown to resist degradation by renal dehydropeptidase I. In a multicenter, open-label, prospective trial, we compared the efficacy and safety of meropenem with imipenem/cilastatin in patients with skin and soft tissue infections. Patients received either 500 mg of meropenem every 8 hours (n = 184) or 500 mg of imipenem/cilastatin every 6 hours (n = 193), by intravenous infusion for an average of 6 to 7 days. Satisfactory clinical responses were achieved in 120 (98%) of 123 assessable meropenem-treated patients and in 120 (95%) of 126 assessable imipenem/cilastatin-treated patients. Satisfactory bacteriologic responses were achieved in 120 (98%) of 123 assessable meropenem-treated patients and in 120 (95%) of 126 assessable imipenem/cilastatin-treated patients. Satisfactory bacteriologic response rates were high as well: 94% with meropenem and 91% with imipenem/cilastatin. Between-group differences in satisfactory response rates were not significant (95% confidence interval, -2.29 to 6.93 [clinical]; -2.73 to 10.39 [bacteriologic]). Overall pathogen eradication rates (for aerobes and anaerobes) were slightly higher for meropenem. Elevated liver enzymes were the most frequent adverse events in each treatment group. Meropenem was well tolerated and as effective as imipenem/cilastatin in treatment of hospitalized patients with skin and soft tissue infections.

Prophylaxis in bowel surgery

The busy colon and rectal surgeon deals daily with a sea of bacteria. Using good surgical judgment as well as time-honored techniques and innovative equipment the postoperative results are generally good. The role that appropriately administered efficacious antibiotics play in this scenario should not be underestimated and can only be realized when historical controls are evaluated. The results of these studies of antibiotic bowel preparation suggest that many different approaches may be equally effective in reducing infection after elective colonic resection. Certain features, however, appear to be common to most of the studies. 1 Oral antibiotic regimens with both aerobic and anaerobic activity (e.g., neomycin/erythromycin base) were used. 2 The oral agents were given in limited doses the day before operation. 3 Addition of systemic antibiotic agents without broad-spectrum coverage to the oral regimen generally did not improve the results. 4 Use of broad-spectrum parenteral antibiotic agents alone was associated with a lower infection rate than the use of systemic agents having only limited coverage. 5 Addition of a broad-spectrum parenteral antibiotic to the oral antibiotics may further reduce the postoperative infection rate. 6 Parenteral or oral antibiotics should be administered only for short periods of time during the perioperative period. Since the general acceptance of the approach outlined above, infection rates have decreased and the number of clinical studies reported has drastically decreased. The authors do feel, however, that there is a need for further study to outline possible benefits of other appropriate regimens (34).

Preventive antibiotic usage in traumatic thoracic injuries requiring closed tube thoracostomy

OBJECTIVE

To evaluate the safety and effectiveness of antibiotics in reducing the infectious complications following closed tube thoracostomy for isolated chest trauma.

DESIGN

Double-blind, randomized clinical trial.

SETTING

Medical school affiliated large urban teaching hospital and trauma center.

PATIENTS

One hundred nineteen of 159 patients over 18 years old presenting to the emergency department requiring closed tube thoracostomy for isolated chest injuries (113 penetrating, 6 blunt).

INTERVENTION

Patients received either placebo or 1 g cefonicid daily intravenously started at chest tube insertion and stopped within 24 h of removal.

MEASUREMENTS AND RESULTS

The development of wound infections, pneumonia (CDC criteria), or empyema; the incidence of adverse events; length of hospitalization. One nonspecific infection was seen in the cefonicid group (1.6 percent) and six respiratory tract infections (10.7 percent) in the placebo group (three empyema, one empyema with pneumonia, two pneumonia) (p = 0.0505; p = 0.0094 [excluding nonspecific infection]). No significant differences with antibiotic use were seen in the duration of chest tube use (p = 0.766), peak WBC counts (p = 0.108), lower peak temperatures (p = 0.063), or length of hospitalization (p = 0.165). Patients who developed infectious complications averaged approximately 8 days longer hospitalization than those without (p < 0.0001).

CONCLUSION

This study showed that patients receiving antibiotics had a significantly reduced rate of infection than did patients administered placebo. No significant adverse events were seen in either group.

Risk of infection, infecting flora and treatment considerations in penetrating abdominal trauma

Infectious complications postoperatively for penetrating abdominal trauma are a major cause of morbidity, which contributes significantly to increased length of hospitalization stay and the cost of patient care. The results of recent studies have suggested that the probability of a major infection after traumatic intestinal perforation of the individual patient can be predicted from risk factors noted at the time of the operation. The factor most closely associated with the development of infection is peritoneal contamination by intestinal contents. Other significant risk factors (p < 0.05) are the number of organs injured, number of units of blood administered, ostomy formation for left colonic injury and patient age. The risk of patients being infected can be predicted and thereby used to guide postoperative treatment decisions. Adjusting trauma care choices in antibiotics, duration of antibiotic administration and incisional wound management could result in significant savings. Standard operative procedures, the use of parenteral antibiotics (the duration of which has been one to two days in most recent studies) effective against endogenous aerobic and anaerobic organisms and leaving the surgical incision open decrease the incidence of postoperative wound infection. Despite such preventive measures, major infection remains a problem.

Anaerobes from a surgical perspective

Before the early 1970s, a large proportion of samples collected from sites of postoperative wound infections yielded no pathogens upon routine culture yet did contain pleomorphic forms visible upon gram staining. The inability to recover pathogens often led to incorrect choices of antibiotics for empirical therapy and thus to clinical failures of therapy. It is now known that many of these infections were due to the various endogenous anaerobic constituents of the normal human microflora. Because of advances in the techniques used for anaerobic specimen collection and culture, anaerobic bacteria are now routinely recovered from a variety of intraabdominal and postoperative soft-tissue infections. In all but clean operative procedures, the causative organisms often reflect the normal aerobic and anaerobic flora of the resected organ. Before colonic surgery, counts of both aerobes and anaerobes must be reduced by appropriate mechanical cleansing and antibiotic administration. Successful treatment of surgical infections includes both the implementation of careful operative technique and the choice of appropriate antibiotics.

Variability of laboratory coat resistance to blood strikethrough

Protection from contamination by potentially infectious fluids is an increasingly important aspect of hospital safety programs. Technical personnel in clinical laboratories may handle numerous samples of human blood and other fluids daily, and to protect themselves against exposure to bloodborne pathogens they routinely wear laboratory coats. We studied the effectiveness of six disposable (polypropylene; either spun-bond or spun-bond/melt-blown/spun-bond construction) and four reusable (polyester-cotton) laboratory coats in preventing blood passage. Fabrics (1018 samples) were tested at six time durations (1 s-5 min) and five pressures [1.7-13.8 kPa (0.25-2.0 psi)]. A standard spray test used to evaluate resistance to wetting showed that reusable coats were less repellent than disposables (P &lt; 0.05). Pressure testing showed that reusable and spun-bond coats allowed greater blood passage than the spun-bond/melt-blown/spun-bond. Laboratory coats should be chosen that have sufficient resistance to blood or other body fluid passage for the task performed and for the period of time used.

Variability of laboratory coat resistance to blood strikethrough

Protection from contamination by potentially infectious fluids is an increasingly important aspect of hospital safety programs. Technical personnel in clinical laboratories may handle numerous samples of human blood and other fluids daily, and to protect themselves against exposure to bloodborne pathogens they routinely wear laboratory coats. We studied the effectiveness of six disposable (polypropylene; either spun-bond or spun-bond/melt-blown/spun-bond construction) and four reusable (polyester-cotton) laboratory coats in preventing blood passage. Fabrics (1018 samples) were tested at six time durations (1 s-5 min) and five pressures [1.7-13.8 kPa (0.25-2.0 psi)]. A standard spray test used to evaluate resistance to wetting showed that reusable coats were less repellent than disposables (P < 0.05). Pressure testing showed that reusable and spun-bond coats allowed greater blood passage than the spun-bond/melt-blown/spun-bond. Laboratory coats should be chosen that have sufficient resistance to blood or other body fluid passage for the task performed and for the period of time used.

Wound and intraabdominal infections: microbiological considerations and approaches to treatment

Aerobic and anaerobic bacteria normally found in the human endogenous gastrointestinal microflora are the most frequent isolates from both postoperative incisional infections and intraabdominal infections. Experimental and clinical studies of intraabdominal infections have shown that many factors are important for successful treatment. Most important is rapid diagnosis followed by a carefully chosen and performed operation. The initial choice of antibiotics with both aerobic and anaerobic coverage has been associated with a high level of therapeutic success in both clinical and experimental settings. In addition, patients with severe intraabdominal infections appear to benefit from a scheduled postoperative relaparotomy with irrigation and exploration, which is most often done today with a zipper technique and which reduces the bacterial burden within the peritoneal cavity. The use of this approach may facilitate the action of properly chosen and administered parenteral antibiotics.

Irrigation of the abdominal cavity in the treatment of experimentally induced microbial peritonitis: efficacy of ozonated saline

Ozone is an oxidizing agent possessing potent in vitro microbicidal capacity. This study was designed to address the extent to which irrigation of the contaminated abdominal cavity using a saline solution primed with ozone is effective in reducing morbidity and mortality. Gelatin capsules containing different quantities of a premixed slurry of filtered human fecal material were implanted in the peritoneal cavities of a preliminary series of rats. Three inocula concentrations were selected for later experiments, based upon their ability to produce morbid consequences: (1) high (100% 1-day mortality), (2) medium (70% 3-day mortality, 100% abscess rate in survivors), and (3) low (100% 10-day survival, 100% abscess rate). Fecal and abscess bacteriology were similar in all rats. The peritoneal cavities of 240 rats then underwent fecal-capsule implantation (three groups of 80 rats/inoculum concentration). At celiotomy 4 hours later, equal numbers of rats from each group were randomly assigned to one of four protocols: (1) no irrigation, (2) normal saline irrigation, (3) saline-cephalothin irrigation, and (4) ozonated saline irrigation. Each treatment lasted 5 minutes, using 100 ml of irrigation fluid. Mortality was significantly reduced when, in lieu of no irrigation, any of the irrigation solutions were used. Additionally, ozonated saline statistically proved the most effective irrigating solution for reducing abscess formation in survivors.

Comparison of oral fleroxacin with oral amoxicillin/clavulanate for treatment of skin and soft tissue infections

Oral fleroxacin, 400 mg once a day, and oral amoxicillin/clavulanate potassium (AMX/CP), 400 mg/125 mg three times a day, administered for 4-21 days, were compared for efficacy and safety in the treatment of skin and soft tissue infections. A total of 113 patients were enrolled in a multicenter, randomized, double-blind trial; 57 were assigned to fleroxacin and 56 to AMX/CP. A total of 22 and 33 patients in the fleroxacin and AMX/CP groups, respectively, were evaluable for efficacy. The most common diagnoses were skin abscess (14; 62%) and wound infections (5; 23%) in the fleroxacin group and skin abscess (17; 52%) and skin ulcer (9; 27%) in the AMX/CP group. A total of 20 (91%) of the fleroxacin-treated patients and 29 (88%) of the AMX/CP-treated patients were bacteriologically cured (two fleroxacin- and one AMX/CP-treated patients developed super-infection). The eradication rate for Staphylococcus aureus was 100% (11 of 11) in the fleroxacin group and 89% (17 of 19) in the AMX/CP group; 18 (82%) of the fleroxacin group and 25 (76%) of the AMX/CP group were clinically cured. Adverse events were seen in 22% (12 of 54) of the fleroxacin group and 25% (13 of 53) of the AMX/CP group. None were serious. Bacteriologic and clinical cure rates and safety results for the two groups were similar. The small sample size precluded statistical analysis at the 95% confidence level.

Efficacy of a beta-lactamase inhibitor combination for serious intraabdominal infections

A double-blind trial was conducted in 385 patients with suspected bacterial intra-abdominal infections to compare the efficacy and safety of ampicillin-sulbactam with cefoxitin. Patients were randomized to receive either 3 g ampicillin-sulbactam (2 g ampicillin-1 g sulbactam), or 2 g cefoxitin, every 6 hours. To be evaluable, patients had to demonstrate positive culture evidence of peritoneal infection at the time of operation. A total of 197 patients were evaluable for clinical efficacy. The two treatment groups were comparable in demographic features and in the presence of risk factors for infection. Clinical success (absence of infection and of adverse drug reaction) was observed in 86% of patients in the ampicillin-sulbactam group and 78% in the cefoxitin group. Eradication of infection occurred in 88% of the ampicillin-sulbactam group and 79% of the cefoxitin group. There were no differences in the nature or frequency of side effects observed in the two groups. Ampicillin-sulbactam demonstrated no difference in safety or efficacy when compared with cefoxitin in the treatment of serious intra-abdominal infections of bacterial origin.

Prospective alterations in therapy for penetrating abdominal trauma

In a double-blind, randomized study, 170 patients with traumatic perforation of the gastrointestinal tract were administered an advanced-generation cephalosporin. Patients were divided into infection risk groups (< or = 40%, low; 40% to 70%, mid; and > 70%, high) at surgical closure using a logistic regression formula based on four proved risk factors--age, blood replacement, ostomy, and the number of organs injured. Patients in the low group received 2 days of antibiotic therapy; those in the mid to high group received 5 days of antibiotic therapy. Those patients in the low to mid group had primary wound closure; those in the high group had their wounds packed open and closed later. Most of the patients (144 [85%]) were in the low group. Their major and minor infection rates (10% and 12%, respectively) were not significantly different from 145 historic control subjects receiving 5 days of antibiotic therapy (9% major; 14% minor). Patients in the mid to high group showed a greater incidence of major infections (46%) but a similar incidence of minor infections (12%). The results indicate that risk factors can be used to identify low-risk patients who require only short-term antibiotic therapy and primary wound closure. The remaining patients are at greater risk for infection despite prolonged antibiotic therapy and delayed wound closure.

Evaluation of new anti-infective drugs for surgical prophylaxis. Infectious Diseases Society of America and the Food and Drug Administration

It has been established by substantial research that antimicrobial prophylaxis for various surgical procedures can reduce the risk of postoperative morbidity and mortality. When the incidence of infectious complications is high, the reduction with prophylaxis is most dramatic. However, even for many "clean" procedures (vascular procedures, total joint replacement), the small reduction in potentially calamitous complications justifies the use of prophylaxis. Many issues of detail remain unanswered: timing and duration of administration of antimicrobial drug; type of drug; use of topical anti-infective agents as ancillary measures; and choices for high-risk individuals and others ordinarily excluded from clinical trials. An approach to the conduct of clinical trials of anti-infective drugs for surgical prophylaxis is provided. Both general guidelines and specific recommendations for total hip replacement, colorectal operations, appendectomy, and transurethral resection of the prostate are included.

Isolation gowns: a false sense of security?

BACKGROUND

Isolation gowns have traditionally been used in health care situations to protect against microbial contamination. There is now concern over protection of the health care worker from contamination by patients' blood and body fluids. We quantitatively determined the effectiveness of commercially available isolation gowns against human blood leakage or strike through.

METHODS

More than 1200 samples of 11 types of disposable gown and one type of reusable gown (new and washed 40 and 80 times) were tested at five different pressures (0.25 to 2 psi) and six durations (1 second to 2 minutes) by means of an apparatus designed to simulate pressures generated during gown usage.

RESULTS

In all studied conditions, testing showed significant differences (p less than 0.0001) in the amount of strike through allowed by the gowns and demonstrated important differences in the gowns' protective capabilities.

CONCLUSION

Although traditional thought assumes that isolation gowns protect the wearer from contamination, our data show this belief may provide a false sense of security.