Spinal Anesthesia or General Anesthesia for Hip Surgery in Older Adults.

BACKGROUND: The effects of spinal anesthesia as compared with general anesthesia on the ability to walk in older adults undergoing surgery for hip fracture have not been well studied. METHODS: We conducted a pragmatic, randomized superiority trial to evaluate spinal anesthesia as compared with general anesthesia in previously ambulatory patients 50 years of age or older who were undergoing surgery for hip fracture at 46 U.S. and Canadian hospitals. Patients were randomly assigned in a 1:1 ratio to receive spinal or general anesthesia. The primary outcome was a composite of death or an inability to walk approximately 10 ft (3 m) independently or with a walker or cane at 60 days after randomization. Secondary outcomes included death within 60 days, delirium, time to discharge, and ambulation at 60 days. RESULTS: A total of 1600 patients were enrolled; 795 were assigned to receive spinal anesthesia and 805 to receive general anesthesia. The mean age was 78 years, and 67.0% of the patients were women. A total of 666 patients (83.8%) assigned to spinal anesthesia and 769 patients (95.5%) assigned to general anesthesia received their assigned anesthesia. Among patients in the modified intention-to-treat population for whom data were available, the composite primary outcome occurred in 132 of 712 patients (18.5%) in the spinal anesthesia group and 132 of 733 (18.0%) in the general anesthesia group (relative risk, 1.03; 95% confidence interval [CI], 0.84 to 1.27; P = 0.83). An inability to walk independently at 60 days was reported in 104 of 684 patients (15.2%) and 101 of 702 patients (14.4%), respectively (relative risk, 1.06; 95% CI, 0.82 to 1.36), and death within 60 days occurred in 30 of 768 (3.9%) and 32 of 784 (4.1%), respectively (relative risk, 0.97; 95% CI, 0.59 to 1.57). Delirium occurred in 130 of 633 patients (20.5%) in the spinal anesthesia group and in 124 of 629 (19.7%) in the general anesthesia group (relative risk, 1.04; 95% CI, 0.84 to 1.30). CONCLUSIONS: Spinal anesthesia for hip-fracture surgery in older adults was not superior to general anesthesia with respect to survival and recovery of ambulation at 60 days. The incidence of postoperative delirium was similar with the two types of anesthesia. (Funded by the Patient-Centered Outcomes Research Institute; REGAIN ClinicalTrials.gov number, NCT02507505.).

Long-term Outcomes with Spinal versus General Anesthesia for Hip Fracture Surgery: A Randomized Trial.

BACKGROUND: The effects of spinal versus general anesthesia on long-term outcomes have not been well studied. This study tested the hypothesis that spinal anesthesia is associated with better long-term survival and functional recovery than general anesthesia. METHODS: A prespecified analysis was conducted of long-term outcomes of a completed randomized superiority trial that compared spinal anesthesia versus general anesthesia for hip fracture repair. Participants included previously ambulatory patients 50 yr of age or older at 46 U.S. and Canadian hospitals. Patients were randomized 1:1 to spinal or general anesthesia, stratified by sex, fracture type, and study site. Outcome assessors and investigators involved in the data analysis were masked to the treatment arm. Outcomes included survival at up to 365 days after randomization (primary); recovery of ambulation among 365-day survivors; and composite endpoints for death or new inability to ambulate and death or new nursing home residence at 365 days. Patients were included in the analysis as randomized. RESULTS: A total of 1,600 patients were enrolled between February 12, 2016, and February 18, 2021; 795 were assigned to spinal anesthesia, and 805 were assigned to general anesthesia. Among 1,599 patients who underwent surgery, vital status information at or beyond the final study interview (conducted at approximately 365 days after randomization) was available for 1,427 (89.2%). Survival did not differ by treatment arm; at 365 days after randomization, there were 98 deaths in patients assigned to spinal anesthesia versus 92 deaths in patients assigned to general anesthesia (hazard ratio, 1.08; 95% CI, 0.81 to 1.44, P = 0.59). Recovery of ambulation among patients who survived a year did not differ by type of anesthesia (adjusted odds ratio for spinal vs. general, 0.87; 95% CI, 0.67 to 1.14; P = 0.31). Other outcomes did not differ by treatment arm. CONCLUSIONS: Long-term outcomes were similar with spinal versus general anesthesia.

Training Anesthesiology Residents to Care for the Traumatically Injured in the United States.

Training and education for trauma anesthesiology have been predicated on 2 primary pathways: learning through peripheral "complex, massive transfusion cases"-an assumption that is flawed due to the unique demands, skills, and knowledge of trauma anesthesiology-or learning through experiential education, which is also incomplete due to its unpredictable and variable exposure. Residents may receive training from senior physicians who may not maintain a trauma-focused continuing medical education. Further compounding the issue is the lack of fellowship-trained clinicians and standardized curricula. The American Board of Anesthesiology (ABA) provides a section for trauma education in its Initial Certification in Anesthesiology Content Outline. However, many trauma-related topics also fall under other subspecialties, and the outline excludes "nontechnical" skills. This article focuses on the training of anesthesiology residents and proposes a tier-based approach to teaching the ABA outline by including lectures, simulation, problem-based learning discussions, and case-based discussions that are proctored in conducive environments by knowledgeable facilitators.

Pain, Analgesic Use, and Patient Satisfaction With Spinal Versus General Anesthesia for Hip Fracture Surgery : A Randomized Clinical Trial.

BACKGROUND: The REGAIN (Regional versus General Anesthesia for Promoting Independence after Hip Fracture) trial found similar ambulation and survival at 60 days with spinal versus general anesthesia for hip fracture surgery. Trial outcomes evaluating pain, prescription analgesic use, and patient satisfaction have not yet been reported. OBJECTIVE: To compare pain, analgesic use, and satisfaction after hip fracture surgery with spinal versus general anesthesia. DESIGN: Preplanned secondary analysis of a pragmatic randomized trial. (ClinicalTrials.gov: NCT02507505). SETTING: 46 U.S. and Canadian hospitals. PARTICIPANTS: Patients aged 50 years or older undergoing hip fracture surgery. INTERVENTION: Spinal or general anesthesia. MEASUREMENTS: Pain on postoperative days 1 through 3; 60-, 180-, and 365-day pain and prescription analgesic use; and satisfaction with care. RESULTS: A total of 1600 patients were enrolled. The average age was 78 years, and 77% were women. A total of 73.5% (1050 of 1428) of patients reported severe pain during the first 24 hours after surgery. Worst pain over the first 24 hours after surgery was greater with spinal anesthesia (rated from 0 [no pain] to 10 [worst pain imaginable]; mean difference, 0.40 [95% CI, 0.12 to 0.68]). Pain did not differ across groups at other time points. Prescription analgesic use at 60 days occurred in 25% (141 of 563) and 18.8% (108 of 574) of patients assigned to spinal and general anesthesia, respectively (relative risk, 1.33 [CI, 1.06 to 1.65]). Satisfaction was similar across groups. LIMITATION: Missing outcome data and multiple outcomes assessed. CONCLUSION: Severe pain is common after hip fracture. Spinal anesthesia was associated with more pain in the first 24 hours after surgery and more prescription analgesic use at 60 days compared with general anesthesia. PRIMARY FUNDING SOURCE: Patient-Centered Outcomes Research Institute.

Outcomes with spinal versus general anesthesia for patients with and without preoperative cognitive impairment: Secondary analysis of a randomized clinical trial.

INTRODUCTION: The effect of spinal versus general anesthesia on the risk of postoperative delirium or other outcomes for patients with or without cognitive impairment (including dementia) is unknown. METHODS: Post hoc secondary analysis of a multicenter pragmatic trial comparing spinal versus general anesthesia for adults aged 50 years or older undergoing hip fracture surgery. RESULTS: Among patients randomized to spinal versus general anesthesia, new or worsened delirium occurred in 100/295 (33.9%) versus 107/283 (37.8%; odds ratio [OR] 0.85; 95% confidence interval [CI] 0.60 to 1.19) among persons with cognitive impairment and 70/432 (16.2%) versus 71/445 (16.0%) among persons without cognitive impairment (OR 1.02; 95% CI 0.71 to 1.47, p = 0.46 for interaction). Delirium severity, in-hospital complications, and 60-day functional recovery did not differ by anesthesia type in patients with or without cognitive impairment. DISCUSSION: Anesthesia type is not associated with differences in delirium and functional outcomes among persons with or without cognitive impairment.

Emergency Department Airway Management Responsibilities in the United States.

BACKGROUND: In the 1990s, emergency medicine (EM) physicians were responsible for intubating about half of the patients requiring airway management in emergency rooms. Since then, no studies have characterized the airway management responsibilities in the emergency room. METHODS: A survey was sent via the Eastern Association for Surgery and Trauma and the Trauma Anesthesiology Society listservs, as well as by direct solicitation. Information was collected on trauma center level, geographical location, department responsible for intubation in the emergency room, department responsible for intubation in the trauma bay, whether these roles differed for pediatrics, whether an anesthesiologist was available "in-house" 24 hours a day, and whether there was a protocol for anesthesiologists to assist as backup during intubations. Responses were collected, reviewed, linked by city, and mapped using Python. RESULTS: The majority of the responses came from the Eastern Association for Surgery of Trauma (84.6%). Of the respondents, 72.6% were from level-1 trauma centers, and most were located in the eastern half of the United States. In the emergency room, EM physicians were primarily responsible for intubations at 81% of the surveyed institutions. In trauma bays, EM physicians were primarily responsible for 61.4% of intubations. There did not appear to be a geographical pattern for personnel responsible for managing the airway at the institutions surveyed. CONCLUSIONS: The majority of institutions have EM physicians managing their airways in both emergency rooms and trauma bays. This may support the observations of an increased percentage of airway management in the emergency room and trauma bay setting by EM physicians compared to 20 years ago.

Visualization Improves Supraclavicular Access to the Subclavian Vein in a Mixed Reality Simulator.

BACKGROUND: We investigated whether visual augmentation (3D, real-time, color visualization) of a procedural simulator improved performance during training in the supraclavicular approach to the subclavian vein, not as widely known or used as its infraclavicular counterpart. METHODS: To train anesthesiology residents to access a central vein, a mixed reality simulator with emulated ultrasound imaging was created using an anatomically authentic, 3D-printed, physical mannequin based on a computed tomographic scan of an actual human. The simulator has a corresponding 3D virtual model of the neck and upper chest anatomy. Hand-held instruments such as a needle, an ultrasound probe, and a virtual camera controller are directly manipulated by the trainee and tracked and recorded with submillimeter resolution via miniature, 6 degrees of freedom magnetic sensors. After Institutional Review Board approval, 69 anesthesiology residents and faculty were enrolled and received scripted instructions on how to perform subclavian venous access using the supraclavicular approach based on anatomic landmarks. The volunteers were randomized into 2 cohorts. The first used real-time 3D visualization concurrently with trial 1, but not during trial 2. The second did not use real-time 3D visualization concurrently with trial 1 or 2. However, after trial 2, they observed a 3D visualization playback of trial 2 before performing trial 3 without visualization. An automated scoring system based on time, success, and errors/complications generated objective performance scores. Nonparametric statistical methods were used to compare the scores between subsequent trials, differences between groups (real-time visualization versus no visualization versus delayed visualization), and improvement in scores between trials within groups. RESULTS: Although the real-time visualization group demonstrated significantly better performance than the delayed visualization group on trial 1 (P = .01), there was no difference in gain scores, between performance on the first trial and performance on the final trial, that were dependent on group (P = .13). In the delayed visualization group, the difference in performance between trial 1 and trial 2 was not significant (P = .09); reviewing performance on trial 2 before trial 3 resulted in improved performance when compared to trial 1 (P < .0001). There was no significant difference in median scores (P = .13) between the real-time visualization and delayed visualization groups for the last trial after both groups had received visualization. Participants reported a significant improvement in confidence in performing supraclavicular access to the subclavian vein. Standard deviations of scores, a measure of performance variability, decreased in the delayed visualization group after viewing the visualization. CONCLUSIONS: Real-time visual augmentation (3D visualization) in the mixed reality simulator improved performance during supraclavicular access to the subclavian vein. No difference was seen in the final trial of the group that received real-time visualization compared to the group that had delayed visualization playback of their prior attempt. Training with the mixed reality simulator improved participant confidence in performing an unfamiliar technique.

Do we really need an anesthesiologist for routine colonoscopy in American Society of Anesthesiologist 1 and 2 patients?

PURPOSE OF REVIEW: In an era where healthcare costs are being heavily scrutinized, every expenditure is reviewed for medical necessity. Multiple national gastroenterology societies have issued statements regarding whether an anesthesiologist is necessary for routine colonoscopies in American Society of Anesthesiologist (ASA) 1 and 2 patients. RECENT FINDINGS: A large percentage of patients are undergoing screening colonoscopy without any sedation at all, which would not require an independent practitioner to administer medications. Advances in technique and technology are making colonoscopies less stimulating. Advantages to administering sedation, including propofol, have been seen even when not administered under the direction of an anesthesiologist and complications seem to be rare. The additional cost of having monitored anesthesia care appears to be a driving factor in whether a patient receives it or not. SUMMARY: A large multiinstitutional randomized control trial would be necessary to rule out potential confounders and to determine whether there is a safety benefit or detriment to having anesthesiologist-directed care in the setting of routine colonoscopies in ASA 1 and 2 patients. Further discussion would be necessary regarding what the monetary value of that effect is if a small difference were to be detected.

Initiation and Termination of Massive Transfusion Protocols: Current Strategies and Future Prospects.

The advent of massive transfusion protocols (MTP) has had a significant positive impact on hemorrhaging trauma patient morbidity and mortality. Nevertheless, societal MTP guidelines and individual MTPs at academic institutions continue to circulate opposing recommendations on topics critical to MTPs. This narrative review discusses up-to-date information on 2 such topics, the initiation and termination of an MTP. The discussion for each begins with a review of the recommendations and supporting literature presented by MTP guidelines from 3 prominent societies, the American Society of Anesthesiologists, the American College of Surgeons, and the task force for Advanced Bleeding Care in Trauma. This is followed by an in-depth analysis of the main components within those recommendations. Societal recommendations on MTP initiation in hemorrhaging trauma patients emphasize the use of retrospectively validated massive transfusion (MT) prediction score, specifically, the Assessment of Blood Consumption and Trauma-Associated Severe Hemorrhage scores. Validation studies have shown that both scoring systems perform similarly. Both scores reliably identify patients that will not require an MT, while simultaneously overpredicting MT requirements. However, each scoring system has its unique advantages and disadvantages, and this review discusses how specific aspects of each scoring system can affect widespread applicability and statistical performance. In addition, we discuss the often overlooked topic of initiating MT in nontrauma patients and the specific tools physicians have to guide the MT initiation decision in this unique setting. Despite the serious complications that can arise with transfusion of large volumes of blood products, there is considerably less research pertinent to the topic of MTP termination. Societal recommendations on MTP termination emphasize applying clinical reasoning to identify patients who have bleeding source control and are adequately resuscitated. This review, however, focuses primarily on the recommendations presented by the Advanced Bleeding Care in Trauma's MTP guidelines that call for prompt termination of the algorithm-guided model of resuscitation and rapidly transitioning into a resuscitation model guided by laboratory test results. We also discuss the evidence in support of laboratory result-guided resuscitation and how recent literature on viscoelastic hemostatic assays, although limited, highlights the potential to achieve additional benefits from this method of resuscitation.

Performance assessment in airway management training for nonanesthesiology trainees: an analysis of 4,282 airway procedures performed at a level-1 trauma center.

BACKGROUND: Although the use of an anesthesiology "airway" rotation to train the nonanesthesiologist is commonly employed, little data exist on the utility, clinical exposure, and outcomes of these programs. METHODS: A prospectively collected observational dataset of airway procedures completed by trainees in a 4-week, anesthesiology-based, airway rotation at an academic, level-1 trauma center from July 2010 to September 2012 was reviewed. Prospectively defined data points were collected through an online data tool and included patient demographics, location, date, best laryngoscopic view, and attempt details. At the authors' institution, an attending trauma anesthesiologist is present for all intubation attempts. The primary outcome was first-attempt success. RESULTS: A total of 4,282 self-reported, airway procedures were identified. The median number of procedures performed was 50.4 ± 13.2 (range, 20 to 93; 25th quartile = 41; 75th quartile = 57). Multivariate logistic regression analysis modeling of first-attempt success rate identified two independent predictors of success: rotation week (odds ratio, 1.42; 95% CI, 1.32 to 1.61; P < 0.0001) and number of previous intubation attempts before rotation (odds ratio, 1.23; 95% CI, 1.03 to 1.46; P = 0.02. In addition, the percentage of cases with a self-reported laryngoscopic grade 1 view increased significantly from 61 to 74% (P = 0.015) from week 1 to week 4 of the rotation. CONCLUSIONS: An anesthesiology-based program for airway training of nonanesthesiologists demonstrates improved self-reported, perceived first-attempt success over the course of training with improved ability to visualize glottic structures.

The influence of patient position on ultrasound examination of the sciatic nerve in the popliteal fossa: A cross-sectional study.

Introduction/Purpose: Ultrasound-guided popliteal fossa sciatic nerve (PFSN) blocks are performed with patients in the supine, lateral or prone position. No known studies compare the quality of images obtained from each approach. This study examines the quality of supine and prone PFSN ultrasound images. Methods: Thirty-eight adult volunteers were sorted into two groups. Five regional anaesthesiologists performed ultrasound examinations of the PFSN on volunteers in supine and prone positions. Popliteal fossa sciatic nerve image quality was analysed with grayscale techniques and peer evaluation. Popliteal fossa sciatic nerve depth, distance from the popliteal crease and time until optimal imaging were recorded. Results: The grayscale ratio of the PFSN vs. the background was 1.83 (supine) and 1.75 (prone) (P = 0.034). Similarly, the grayscale ratio of the PFSN vs. the immediately adjacent area was 1.65 (supine) and 1.55 (prone) (P = 0.004). Mean depth of the PFSN was 1.6 cm (supine) and 1.7 cm (prone) (P = 0.009). Average distance from the popliteal crease to the PFSN was 5.9 cm (supine) and 6.6 cm (prone) (P = 0.02). Mean time to acquire optimal imaging was 36 s (supine) and 47 s (prone) (P = 0.002). Observers preferred supine positioning 53.8%, prone positioning 22.5% and no preference 23.7% of the time. Observers with strong preferences preferred supine imaging in 70.9% of cases. Conclusions: Supine ultrasound examination offered quicker identification of the PFSN, in a more superficial location, closer to the popliteal crease and with enhanced contrast to surrounding tissue, correlating with observer preferences for supine positioning. These results may influence ultrasound-guided PFSN block success rates, especially in difficult-to-image patients.

A Comparison of Central Venous Access to the Internal Jugular Vein and Two Standard Approaches to the Subclavian Vein: A Study of Cross-Sectional Areas Using Computed Tomography Scans.

Introduction The supraclavicular approach to the subclavian vein has been cited as having many advantages to the infraclavicular approach, including a larger short-axis cross-sectional area, a greater margin of safety, and fewer complications. Methods To examine whether a larger short-axis cross-sectional area of the subclavian vein at the supraclavicular fossa is a potential explanation for the reduction in attempts with the supraclavicular approach seen in a previous study, we examined computed tomography scans from 50 patients (24 M, 26 F). The short-axis cross-sectional areas of the subclavian vein at the mid-clavicular line, the subclavian vein in the supraclavicular fossa, and the internal jugular vein at the level of the thyroid cartilage were calculated. Results The internal jugular vein short-axis cross-sectional area was significantly larger than the subclavian vein short-axis cross-sections measured at each location. We found no difference between the short-axis cross-sectional areas of the subclavian vein or when comparing measurements as a factor of gender, age, or race. Weight had a significant relationship to the short-axis cross-sectional area of the internal jugular vein and subclavian vein at the mid-clavicular vein. Conclusions On supine computed tomographic imaging, the subclavian vein short-axis cross-section was not larger in the supraclavicular fossa than the mid-clavicular line. The short-axis cross-sectional area of the subclavian vein at the supraclavicular fossa does not appear to contribute to the decrease in attempts to access it. Weight, but not necessarily height, appears to be correlated with central vein size.

Ketamine infusion reduces narcotic requirements following gastric bypass surgery: a randomized controlled trial.

BACKGROUND: As the obesity epidemic worsens, anesthesiologists should expect to see more obese patients presenting for surgical procedures. Opioids cause respiratory depression, which has caused complications in patients with obstructive sleep apnea. Opioids can also cause nausea, prolonging the time that patients spend in the postanesthesia care unit. Ketamine is a potential analgesic alternative that may have advantages to narcotics in the bariatric population. OBJECTIVES: To determine whether an intraoperative ketamine infusion would reduce postoperative narcotic use in patients during the first 48 hours after laparoscopic gastric bypass. SETTING: Major academic medical center. METHODS: There were 54 participating patients. The intervention group (n = 27) was randomized to receive 100 µg of fentanyl with anesthesia induction, then a 20-mg bolus of ketamine, followed by a 5 µg/kg/min intraoperative ketamine infusion starting after anesthesia induction and ending after wound closure commenced. The control group (narcotic only, n = 27) also received 100 µg of fentanyl at anesthesia induction and intraoperative boluses of fentanyl at the discretion of the anesthesia team, with .3 mg of hydromorphone administered approximately 45 minutes before the completion of surgery. RESULTS: At 24 hours, the mean morphine-equivalent units (MEUs) were 12.7 (standard deviation [SD], 9.9; 95% confidence interval [CI], 8.8-16.6) for the ketamine group (n = 28) and 16.5 (SD, 9.8; 95% CI, 12.6-20.4) for the control group (n = 28). At 48 hours, the MEUs were 16.7 (SD, 12.0; 95% CI, 11.9-21.4) for the ketamine group and 22.7 (SD, 14.9; 95% CI, 16.8-28.6) for the control group. Cumulative MEUs for 24 hours (P = .039) and 48 hours (P = .058) postoperatively were lower in the ketamine group compared with the narcotic-only (control) group, although the difference at 48 hours did not reach statistical significance. Compared with the narcotic-only group, the ketamine group used 26% fewer MEUs after 24 hours and 31% fewer MEUs after 48 hours. This difference can mostly be attributed to group differences during the first 6 hours after surgery. CONCLUSIONS: Ketamine successfully reduced the amount of opioids required to control bariatric patients' pain at 24 hours postoperatively, but not over the 48-hour postoperative period.

Effects of a Single Rapid Infusion System on Platelet Function in Stored Whole Blood: An Ex Vivo Study.

Introduction Rapid infusion systems (RIS) are used to warm and rapidly infuse crystalloids and blood products. Current guidelines do not approve of platelet transfusion through a RIS, but data supporting these guidelines are scarce. Our hypothesis was that an infusion of whole blood through a RIS would degrade platelet quantity, impede viscoelastic clot strength, and inhibit platelet aggregation response to adenosine diphosphate pathway (ADP) activation. Methods Ten iterations of a simulated scenario of transfusing whole blood via a single brand and make of RIS (Belmont Fluid Management System 2000, Belmont Medical Technologies, Billerica, MA) were performed. Units of whole blood, which were two to nine days old, were leukoreduced prestorage. Blood was used to prime the RIS and then warmed and infused at 100 mL/min into a reservoir. Blood samples were collected before and immediately after infusion. Samples were tested for platelet count, size, and viscoelastic clot strength using thromboelastographic and aggregation assays. Results The study sample (n = 10) included platelets with an average age of 5.3 days. The infusion through the RIS had a detrimental effect on all the maximal amplitudes (MA) of viscoelastic testing: MA ADP (mean difference = -18.7 mm; 95% CI: -24.1 to -13.3, P = 0.004), MA rapid thromboelastography (MA rTEG) (mean difference = -6.0; 95% CI: -10.0 to -2.0, P = 0.008), MA TEG (mean difference = -7.1; 95% CI: -10.9 to -3.4, P = 0.004), mean platelet volume (MPV) (mean difference = -0.3; 95% CI: -0.6 to -0.1, P = 0.02), and platelet count (mean difference = -68.3 × 103/µL; 95% CI: -86.9 to -49.7, P = 0.004). Conclusions Platelet quantity, viscoelastic clot strength, and platelet aggregation response to ADP each decline after infusion through a RIS. Further studies regarding microaggregates and platelet activation are required.

Isolation gowns as a potential work hazard.

OBJECTIVES: Isolation gowns are used as a barrier to bacterial transmission from patient to provider and vice versa. If an isolation gown is ineffective, the patient and provider have a potential breach of safety and increased infection risk. This study compared the bacterial permeability of differently rated, commonly uses isolation gowns to assess their effectiveness in preventing simulated bacterial transmittance, and thus contamination, from patient to provider. METHODS: Serial dilutions of Staphylococcus epidermidis in sterile saline were applied to a simulated skin surface. Unrated and Levels 1 through 4 non-sterile isolation gowns contacted the solution, simulating patient contact. Both sides of the contaminated gowns were then cultured on blood agar by rolling a sterile swab across the gown and evenly inoculating the culture plate. Colony counts from inside and outside of the gowns were compared. Separately, S. epidermidis was placed on a sample of each gown and scanning electron microscopy was used to visualize the contaminated gowns' physical structure. RESULTS: Mean bacterial transmittance from outside of the gown (i.e. patient contact side) to inside of the gowns (i.e. provider clothing or skin side) based on gown rating was as follows: unrated: 50.4% (SD 9.0%); Level 1: 39.7% (SD 11.2%); Level 2: 16.3% (SD 10.3%); Level 3: 0.3% (SD 0.8%); Level 4: 0.0% (SD 0.0%). Scanning electron microscope imaging of unrated, Level 1, and Level 2 gowns revealed gown pore sizes much larger than the bacteria. The Welch one-way analysis of variance statistic showed significant difference dependent on gown-level rating. CONCLUSIONS: Unrated, Level 1, and Level 2 isolation gowns do not provide effective bacterial isolation barriers when bacteria like S. epidermidis make contact with one side of the gown material. Not studied, but implied, is that unrated and lower rated isolation gowns would be as or even more physically permeable to virus particles, which are much smaller than bacteria.