The influence of gender on functional outcomes of lower extremity bypass.

OBJECTIVE: Our aim was to evaluate the effect of gender on early and late procedural and functional outcomes of lower extremity bypass (LEB). METHODS: We reviewed the records of 2576 patients (828 women; 32%) who underwent LEB for claudication or critical limb ischemia (CLI) in the Vascular Study Group of New England from 2003 to 2010. Logistic regression and proportional hazards models were used to adjust for potential confounding differences between genders. Morbidity, mortality, graft patency, freedom from major amputation, ambulation, and living status were analyzed postoperatively and over 1 year. RESULTS: Women were older (70 vs 68 years; P < .001), had more hypertension (89% vs 85%; P = .006), less coronary artery disease (35% vs 39%; P = .03), smoking (73% vs 88%; P < .001), and preoperative statin use (60% vs 64%; P = .04). Women were more likely to have CLI (76% vs 71%; P = .003), and ambulate with assistance at presentation (19% vs 16%; P = .02). Morbidity was similar except women had higher rates of reoperation for thrombosis (4% vs 2%; P < .001) without differences in major amputation (2% vs 1%; P = .13) or in-hospital mortality (1.7% vs 1.7%; P = .96). Women and men with claudication had similar 1-year graft patency rates. Women with CLI had lower rates of primary (hazard ratio [HR], 1.24; 95% confidence interval [CI], 1.03-1.48; P = .02), assisted primary (HR, 1.42; 95% CI, 1.15-1.76; P = .001) and secondary patency (HR, 1.40; 95% CI, 1.10-1.77; P = .006) during the first year compared with men. Freedom from amputation was similar for men and women with CLI (HR, 1.17; 95% CI, 0.84-1.63; P = .36). There were no differences in late survival between women and men with claudication (HR, 0.89; 95% CI, 0.60-1.31; P = .36) or CLI (HR, 0.94; 95% CI, 0.81-1.09; P = .39). More female claudicants were not independently ambulatory at discharge (30% vs 19%; P = .002) and were discharged to a nursing home (15% vs 5%; P < .001) but these differences did not persist at 1 year. Women with CLI were more likely to be nonambulatory at discharge (13% vs 9%; P = .006) and at 1 year (13% vs 8%; P < .001). More women with CLI were discharged to a nursing home (44% vs 35%; P = .01) and resided there at 1 year (11% vs 7%; P = .02). CONCLUSIONS: Women have complication rates similar to men with inferior early and late functional outcomes after LEB. The reduced patency rates in women with CLI did not translate into differences in limb salvage. These findings might help define physician and patient expectations for women before revascularization.

Evaluation of simulation-based training model on vascular anastomotic skills for surgical residents.

INTRODUCTION: Reduced work hours and concerns over patient safety have encouraged surgical educators to find methods to advance resident skills more efficiently. Simulation provides the opportunity to improve technical surgical skills outside the operating room. We hypothesized that practice on surgical task simulators would improve residents' technical performance of vascular anastomotic technique. METHODS: Senior general surgery residents at an academic medical center completed pretests and posttests on 3 vascular surgery simulators: femoral-popliteal bypass, carotid endarterectomy, and abdominal aortic aneurysm repair. The initial training sessions began with a 15-minute instructional video on how to perform the procedures, followed by supervised sessions in anastomotic technique with attending vascular surgeons. Initial individual sessions were videotaped as a pretest, and the final attempt was videotaped as the posttest. Each test was evaluated by a single experienced attending vascular surgeon blinded to the examinees. Anastomoses were graded using a performance rating and a modified objective structured assessment of technical skill rating. Results were analyzed using mixed model P values. RESULTS: The residents showed statistically significant improvement between the pretest and the posttest in both their performance rating (1.9 vs. 2.4, P = 0.02) and the objective structured assessment of technical skill (2.6 vs. 3.1, P = 0.01), as well as in most subsets of each assessment scale. CONCLUSIONS: We conclude that practice using simulated anastomotic models leads to measurable improvement in vascular anastomotic technique in senior general surgery residents.

Crew resource management: using aviation techniques to improve operating room safety.

INTRODUCTION: Since the publication of the Institute of Medicine report estimating nearly 100,000 deaths per year from medical errors, hospitals and physicians have a renewed focus upon error reduction. We implemented a surgical crew resource management (CRM) program for all operating room (OR) personnel. METHODS: In our academic medical center, 19,000 procedures per year are performed in 27 operating rooms. Mandatory CRM training was implemented for all peri-operative personnel. Aviation techniques introduced included a pre-operative checklist and brief, post-operative debrief, read and initial files, and various other aviation-based techniques. Compliance with conduct of the brief/debrief was monitored as well as wrong-site surgeries and retained foreign body events. The malpractice insurance database for claims was also queried for the period prior to and after training. RESULTS: Initial training was accomplished for 517 people, including all anesthesiologists, surgeons, nurses, technicians, and OR assistants. Pre-operative briefing increased from 6.7 to 99% within 4 mo. Wrong site surgeries and retained foreign bodies decreased from a high of seven in 2007 to none in 2008, but, after 14 mo without additional training, these rose to five in 2009. Malpractice expenses (payouts and legal fees) totaled $793,000 (2003-2007), but have been zero since 2008. DISCUSSION: CRM training and implementation had an impact on reducing the incidence of wrong site surgery and retained foreign bodies in our operating rooms. However, constant reinforcement and refresher training is necessary for sustained results. Though no one technique can prevent all errors, CRM can effect culture change, producing a safer environment.

Telemedicine to a moving ambulance improves outcome after trauma in simulated patients.

BACKGROUND: Rural trauma victims often require prolonged transport by s with limited scopes of practice. We evaluated the impact of telemedicine (TM) to a moving ambulance on outcomes in simulated trauma patients. METHODS: This is an institutional review board approved, prospective double-blind study. Three trauma scenarios (blunt torso trauma, epigastric stab wound, and closed head injury) were created for a human patient simulator. Intermediate emergency medical technicians (EMTs; n = 20) managed the human patient simulator, in a moving ambulance. In the TM group, physicians (n = 12) provided consultation. In the non-TM group, EMTs communicated with medical control by radio, as necessary. We tabulated the fraction of 13 key signs, 5 pathologic processes, and 12 key interventions that were performed. Vital signs and Sao2 (%) were recorded. Data were compared using the Wilcoxon rank-sum test. RESULTS: Lowest Sao2 (84 ± 0.7 vs. 78 ± 0), lowest systolic blood pressure (70 ± 1 vs. 53 ± 1), and highest heart rate (144 ± 0.9 vs. 159 ± 0.5) were significantly improved in the TM group (p < 0.001). Recognition rates for key signs (0.96 ± 0.01 vs. 0.79 ± 0.05), processes (0.98 ± 0.02 vs. 0.75 ± 0.05), and critical interventions (0.92 ± 0.02 vs. 0.49 ± 0.03) were higher in the TM group (p < 0.003). EMTs were successfully guided through needle decompression procedures in 22 of 24 cases (zero in the non-TM group). CONCLUSION: TM to a moving ambulance improved the care of simulated trauma patients. Furthermore, procedurally naïve EMTs were able to perform needle thoracostomy and pericardiocentesis with TM guidance.

Compartment syndrome in the setting of vascular injury.

Compartment syndrome after extremity vascular injury has gained attention with the current conflicts in Iraq and Afghanistan. Compartment syndrome after extremity vascular injury is due to the initial ischemic insult and reperfusion injury. Complications from compartment syndrome can be lessened by fasciotomy, which is reviewed in this article.

Expert visual guidance of ultrasound for telemedicine.

Expert visual guidance (EVG) is computer assistance that displays to the examiner how the image plane moves towards (or away from) a desired anatomical location as the ultrasound probe is manipulated over the patient's body. We tested whether EVG by a remote expert could assist inexperienced examiners in acquiring abdominal ultrasound images. The inexperienced examiners were 20 medical students, who were randomly assigned to verbal instruction alone (Group 1) or to EVG (Group 2). The examiners were tested on their ability to visualize the abdominal aorta and the right kidney. Group 2 was more successful in identifying specified anatomy in longitudinal and cross-sectional views of the aorta (95 vs. 75%, P = 0.032) and kidney (98 vs. 88%, P = 0.09). The groups succeeded equally well in obtaining a true cross-sectional view of the aorta. Kidney length was also similar when measured by the two groups. The results demonstrate that an inexperienced ultrasonographer can be significantly assisted by EVG compared to verbal instruction alone. This could be useful for tele-mentoring in rural hospitals as well as for teaching, both in person and at a remote site.

Benefits of a telepsychiatry consultation service for rural nursing home residents.

Psychiatric care for nursing home residents is difficult to obtain, especially in rural areas, and this deficiency may lead to significant morbidity or death. Providing this service by videoconference may be a helpful, cost-effective, and acceptable alternative to face-to-face treatment. We analyzed data for 278 telepsychiatry encounters for 106 nursing home residents to estimate potential cost and time savings associated with this modality compared to in-person care. A total of 843.5 hours (105.4 8-hour work days) of travel time was saved compared to in-person consultation for each of the 278 encounters if they had occurred separately. If four resident visits were possible for each trip, the time saved would decrease to 26.4 workdays. Travel distance saved was 43,000 miles; 10,750 miles if four visits per trip occurred. More than $3,700 would be spent on gasoline for 278 separate encounters; decreased to $925 for four visits per roundtrip. Personnel cost savings estimates ranged from $33,739 to $67,477. Physician costs associated with additional travel time ranged from $84,347 to $253,040 for 278 encounters, or from $21,087 to $63,260 for four encounters per visit. The telepsychiatry approach was enthusiastically accepted by virtually all residents, family members, and nursing home personnel, and led to successful patient management. Providing psychiatric care to rural nursing home residents by videoconference is cost effective and appears to be a medically acceptable alternative to face-to-face care. In addition, this approach will allow many nursing homes to provide essential care that would not otherwise be available.

Use of the rectus abdominis muscle flap to fill a retroperitoneal defect following blast injury.

Wartime injuries from explosive devices have created the need for atypical responses to devastating and unusual injuries. We report a case of an explosive abdominal injury that produced a huge defect in the posterior abdominal wall which was ultimately repaired with a rectus abdominus flap, an usual use of this versatile muscle flap. The rectus abdominus muscle may be another tool available for the repair of wartime injuries.

The feasibility of using ultrasound and video laryngoscopy in a mobile telemedicine consult.

Emergency healthcare systems in rural communities often have limited access to experienced trauma and emergency physicians. Advanced telecommunication technologies may offer an opportunity to help meet this need. We evaluated healthcare providers' satisfaction with the audio and visual components of an existing telemedicine system, and asked them whether emergency medical services (EMS) personnel could be supported via telemedicine guidance, using video laryngoscopy and ultrasonography, during vulnerable transport periods. Physicians and technologists at a central workstation were linked to a telemedicine-equipped ambulance providing real-time audio and visual communications during patient transport. A scoring system was created for system evaluation using a scale of 1-9. Seven evaluators observed ultrasonography of the carotid vessels and abdominal aorta. Nine evaluators observed an intubation with video laryngoscopy. These observers rated the quality of the images transmitted from the ambulance. Evaluators were asked if this telemedicine system would be suitable for telementoring advanced technical procedures. Mean rating for technical satisfaction with ultrasound was 5.1, the majority of evaluators estimated that they could telementor an abdominal ultrasound examination. The mean rating for technical satisfaction with laryngoscopy was 7.2 with 100% of evaluators estimating they could use the system to telementor intubation. The rating for laryngoscopy was significantly higher than for ultrasound (p = 0.01). Results of this study suggest that telemedicine may provide an advanced support mechanism for rural EMS personnel and patients. Procedures for advanced airway management and ultrasound diagnosis may someday be managed using a remote telepresence.

Effectiveness of lectures attended via interactive video conferencing versus in-person in preparing third-year internal medicine clerkship students for Clinical Practice Examinations (CPX).

BACKGROUND: The current practice in medical education is to place students at off-site locations. The effectiveness of these students attending remote lectures using interactive videoconferencing needs to be evaluated. PURPOSE: To determine whether lecture content covering clinical objectives is learned by medical students located at remote sites. METHODS: During the University of Vermont medicine clerkship, 52 medical students attended lectures both in person and via 2-way videoconferencing over a telemedicine network. The study used a crossover design, such that all students attended half of the lectures in person and half using videoconferencing. At the end of the clerkship, students were assessed via a Clinical Practice Examination (CPX), with each student completing 1 exam for material learned in person and 1 for material learned over telemedicine. RESULTS: Exam scores did not differ for the 2 lecture modes, with a mean score of 76% for lectures attended in person and a mean score of 78% for lectures attended via telemedicine (p = 0.66). CONCLUSIONS: Students learn content focused on clinical learning objectives as well using videoconferencing as they do in the traditional classroom setting.

Toward optimal recording of surgical complications: concurrent tracking compared to the discharge data set.

BACKGROUND: Information extracted from the hospital discharge data set is used increasingly for outcomes research and for benchmarking hospital and provider performance. The accuracy of these data in detecting vascular complications has never been validated. METHODS: We compared morbidity and mortality data derived from the hospital discharge data set to similar data recorded concurrently by our Surgical Activity Tracking System (SATS) for 1 year on the vascular surgery service. RESULTS: Of 798 total admissions, no complications were detected by either system in 598 admissions (75%). In 200 admissions (25%), there were 335 complications, including 24 deaths (3.0%), that occurred either in-hospital or within 30 days of the date of operation or the date of discharge for nonoperative admissions. Of the 335 complications, 180 (53.7%) were recorded by both systems; the SATS missed 59 complications recorded in the hospital discharge data set (17.6%), whereas the hospital discharge data set missed 96 complications recorded in the SATS (28.7%, P = .003). Of the 289 in-hospital complications, the SATS recorded 230 (79.5%), whereas the hospital discharge data set recorded 229 (79.2%). Of the 24 deaths, the hospital discharge data set missed 6 that occurred after discharge but within the 30-day reporting period CONCLUSIONS: Both systems are not completely accurate for tracking inpatient complications. The SATS was more representative than the hospital discharge data set in capturing 30-day morbidity and mortality. An amalgamation of the 2 systems would provide more optimal tracking of complications.

Pressure elevation slows the fibroblast response to wound healing.

OBJECTIVE: Chronic venous insufficiency and venous ulceration are consequences of elevated pressure within affected limbs. We hypothesized that wounded cells maintained at different atmospheric pressures heal at different rates and that pressure would adversely affect the processes necessary for wound healing. METHODS: We have developed an in vitro model that replicates venous hypertension in a unique pressurized incubator using neonatal fibroblasts. Neonatal fibroblasts grown to confluence were wounded with a standardized linear incision and then placed in a unique pressure incubator at atmospheric pressure, atmospheric pressure plus 30 mm Hg, atmospheric pressure plus 60 mm Hg, and atmospheric pressure plus 120 mm Hg. Cells were observed daily until complete healing of the wound occurred. Twelve to 18 hours after wounding, proliferating cell nuclear antigen analysis was done by immunocytochemistry. RESULTS: Wounds at atmospheric pressure plus 30 mm Hg were healed by day 3, those at atmospheric pressure plus 60 mm Hg by day 4, and those grown at atmospheric pressure plus 120 mm Hg took > or =4 days for complete healing. Significantly less proliferating cell nuclear antigen activity was present in cells grown at atmospheric pressure plus 60 mm Hg (P < .0001) and atmospheric pressure plus 120 mm Hg (P < .02). Wound edge fluorescence analysis demonstrated less fluorescence in each group compared with atmospheric pressure. CONCLUSIONS: In this model of wound healing under pressure, neonatal fibroblasts grown to confluence and given a standardized wound displayed characteristics consistent with delayed healing. Elevated pressure has a role in the delayed migration and proliferation seen in this model. CLINICAL RELEVANCE: The elevated pressure in patients with venous insufficiency causes their wounds to heal less quickly. Understanding and quantifying the physiology and role of elevated tissue pressure due to venous hypertension will lead to a better understanding of wound healing in these patients.

The use of telemedicine for delivering continuing medical education in rural communities.

Physicians in rural communities have limited access to continuing medical education (CME) opportunities. We hypothesized that CME could be delivered via a telemedicine network as effectively as in-person. Our institution delivers CME lectures and grand rounds in Burlington, Vermont, for in-person attendees, and also via a telemedicine network that links 14 hospitals in Vermont and rural northeastern New York. All participants complete an evaluation questionnaire to receive CME credit. We compared the questionnaire responses of those attending in person with those attending via the telemedicine network. From October 1, 2000 to June 30, 2003, there were 4733 CME sessions, 650 of which had both in-person and telemedicine attendees. Responses from these 650 sessions were compared. Most questions relating to lecture quality scored higher for in-person attendees. Compared to having the presenter in the room, telemedicine attendance was judged to be "more effective" in 19% (n = 334), "as effective" in 60%, (n = 1074), and "less effective" in 21% (n = 367). Eighteen percent of telemedicine attendees said they would have traveled to attend the session. Telemedicine-delivered CME was considered at least as effective as in-person CME 79% of the time. Travel was avoided for 18% of the remote attendees. CME was delivered where it would not have been obtained for 82% of the remote attendees. Telemedicine systems can be used to deliver CME, in spite of lower overall ratings compared to in-person attendance.

Pressure-induced cellular senescence: a mechanism linking venous hypertension to venous ulcers.

INTRODUCTION: Slow healing of ulcers in chronic venous insufficiency (CVI) has long been thought secondary to venous hypertension. Dermal fibroblasts isolated from venous ulcers have morphologies and protein production suggestive of premature aging. In this study, we hypothesized that neonatal fibroblasts (NNF) cultured under elevated pressure will demonstrate premature aging and that this effect will be augmented by an inflammatory mediator, transforming growth factor beta (TGF-beta). MATERIALS AND METHODS: A unique pressure incubator was used to culture NNF at atmospheric pressure (ATM), ATM + 30 mmHg, ATM + 60 mmHg, and ATM +120 mmHg. Some pressure-exposed NNF were also cultured with TGF- beta (1 ng/ml). Growth rates were determined by flow cytometry. Senescent cells were identified by staining with a marker for cellular senescence, beta-galactosidase (SA-beta-Gal). Light microscopy and digital imaging were used to evaluate cell morphology. Paired linear models and comparison of the slopes were used for statistical analysis of growth. chi2 analysis was used to compare senescence rates. RESULTS: NNF cultured at ATM + 60 mmHg and ATM + 120 mmHg showed increased SA-beta-Gal activity (P <0.05), and reduced growth rates (P <0.05) at 11 days. These effects were not seen at ATM + 30 mmHg. NNF grown with TGF-beta did not show augmented SA-beta-Gal staining. CONCLUSIONS: Pressure-exposed NNF demonstrated an accelerated aging phenomenon similar to fibroblasts isolated from venous ulcers. This aging effect was directly related to the level of pressure. TGF-beta did not augment the aging effect. This study suggests that pressure elevations result in altered cell function and accelerated aging that may contribute to the slowed healing seen in patients with venous insufficiency.

Relation of augmented platelet reactivity to the magnitude of distribution of atherosclerosis.

The extent of luminal involvement of atherosclerotic vascular disease and platelet reactivity portend subsequent cardiovascular events. This study was designed to determine whether platelet reactivity correlates with the extent of the territorial distribution of vascular disease. Blood was obtained from 130 patients who had known atherosclerotic vascular disease categorized as being in > or =1 of the following territories: coronary artery disease (CAD; n = 89), cerebrovascular disease (n = 36), and peripheral arterial disease (n = 61). Platelet reactivity, i.e., the activation of platelets in response to a low concentration of adenosine diphosphate (0.2 micromol/L), was measured using flow cytometry. Patients with vascular disease in >1 territory compared with those with disease in only 1 territory had greater platelet reactivity with respect to P-selectin expression (p = 0.01). The percentages of platelets expressing P-selectin (mean +/- SD) were 6.4 +/- 4.2 in patients who had involvement of 1 territory (n = 88), 10.0 +/- 6.8 in those who had involvement of 2 territories (n = 28), and 10.1 +/- 9.9 in those who had involvement of 3 territories (n = 14). Patients who had CAD and diabetes mellitus had greater P-selectin expression than did those who had CAD without diabetes (p <0.02 for interaction). Thus, platelet reactivity is greater in patients who have more extensive territorial distribution of atherosclerotic vascular disease and in those who have CAD and diabetes mellitus. Accordingly, patients who have more widely distributed vascular disease are likely to derive particular benefit from antiplatelet regimens that suppress platelet function to a greater extent.

Medical student evaluations of lectures attended in person or from rural sites via interactive videoconferencing.

BACKGROUND: Interactive videoconferencing may be an effective way for medical students on remote rotations to attend teaching sessions at the main campus. PURPOSE: To compare medical student evaluations of lectures for those attending in person and those attending through interactive videoconferencing. METHODS: Lecture evaluations were completed by medical students on University of Vermont College of Medicine clinical clerkship rotations. Students on clerkships at rural sites attended lectures using our telemedicine network. Responses from in-person and remote attendees were compared. RESULTS: Evaluation forms for 110 lectures were received from 648 in-person and 255 remote attendees. All evaluation items were rated "good" or "excellent" by at least 95% of in-person attendees. Over 90% of remote attendees rated nontelemedicine evaluation items, such as appropriateness of lecture topic for students, as good or excellent. Ratings of telemedicine-specific questions, such as ability to hear the lecturer, were lower. CONCLUSIONS: Level of satisfaction was high for most aspects of remote lecture attendance, although not quite as high as for in-person attendance. Improved technical reliability would likely increase remote attendee satisfaction. Overall, lecture attendance using videoconferencing was found to be an acceptable alternative to travel for medical students in rural clerkships.

Evaluating chronic venous disease with a new venous severity scoring system.

BACKGROUND: The Venous Clinical Severity Score (VCSS) has been proposed by the American Venous Forum as an objective means to clinically assess venous disease more completely than with the clinical CEAP classification. However, validation of the VCSS against an objective test is lacking. The purpose of this study was to test the VCSS against abnormalities found on venous ultrasound (US) scans. METHODS: As part of a screening project in a large kindred population with protein C deficiency, VCSS and venous US scanning were performed in 210 patients (420 limbs). A single examiner scored the VCSS (0-3) clinically for pain, varicose veins, edema, skin pigmentation, inflammation, induration, ulcer duration and size, and compressive therapy. Another experienced examiner, blinded to the subject's medical history, performed a US examination of the deep and superficial venous system, with a hand-carried US system. The relationship between US and VCSS scores was analyzed by calculating an odds ratio (OR) and its 95% confidence interval (CI). RESULTS: Of the 420 limbs screened, VCSS was 0 in 283 limbs, and VCSS was 1 or greater in the following categories: pain, 63 limbs; varicose veins, 70 limbs; edema, 51 limbs; skin pigmentation, 17 limbs; inflammation, 2 limbs; induration, 8 limbs; and compressive therapy, 9 limbs. The highest total score in any limb was 8. A clear association was seen with the VCSS and abnormalities found on US scans. When the score was dichotomized (0 = normal, 1 = any abnormality), it was a strong predictor of US scan abnormalities; limbs with VCSS greater than 0 had a 26-fold greater chance of US scan abnormalities than did limbs with VCSS = 0 (OR, 26.5; 95% CI, 11-64). With ultrasonography as the standard, sensitivity of VCSS compared with US scans was 89.3%, and specificity was 76.1%. Negative predictive value of VCSS = 0 was 97.9%, and positive predictive value for any positive score was 36.5% CONCLUSIONS: The results of this study are based on a large kindred population with a higher risk for venous disease than found in the general population. Though the VCSS was devised to quantify the severity of chronic venous disease, this study found it a useful screening tool. The VCSS showed good association with abnormalities on US scans, and when VCSS = 0 there is a high likelihood that the patient does not have venous disease. This simple test may prove valuable in clinical practice.

A new in vitro model of venous hypertension: the effect of pressure on dermal fibroblasts.

PURPOSE: Venous hypertension leads to venous stasis ulcers. White cell activation, protein leakage from pressurized capillaries, and cytokine imbalances have all been implicated as indirect effects of venous hypertension that contribute to dermal changes seen in chronic venous insufficiency. The direct effect of increased tissue pressures on dermal elements has not been investigated. Prior studies have shown that fibroblasts isolated from venous ulcers have altered growth rates, morphologies, and protein production similar to senescent or aged fibroblasts. We hypothesize that neonatal fibroblasts (NNFs) cultured in conditions of increased atmospheric pressure will demonstrate altered cell function when compared with those grown at normal atmospheric pressure (ATM). METHODS: A pressure incubator was used to culture populations of NNFs at ATM, 60 mm Hg over ATM (ATM + 60 mm Hg), and 120 mm Hg over ATM (ATM + 120 mm Hg). NNF population growth rates were determined by periodic flow cytometry analysis over a 2-week period. Light microscopy and digital imaging were used to evaluate cell morphology. Senescence-associated B-galactosidase (SA-beta-Gal) activity was determined using the X-Gal stain. Fibronectin production was assessed by exposing cells sequentially to anti-fibronectin antibodies and Oregon Green-conjugated goat anti-mouse secondary antibodies. Flow cytometry then was used to determine relative proportions of cells staining positively for fibronectin. Statistical analysis was accomplished with analysis of variance. RESULTS: Populations of cells grown under increased pressures (both ATM + 60 and ATM + 120) showed reduced growth rates (P <.001). Similarly, morphologies of cells grown under pressure had increased cytoplasm to nuclear ratios with abnormal nuclear shapes. Populations of cells grown under pressure had higher percentages of cells staining positive for fibronectin (ATM = 45%, ATM + 60 = 59%, ATM + 120 = 79%). After 14 days of growth under pressure, fibroblast populations did not demonstrate augmented productions of the senescence marker SA-beta-Gal (ATM =.5%, ATM + 60 =.25%, ATM + 120 =.75%). CONCLUSIONS: This study demonstrated that NNFs grown in culture under increased pressures undergo a transformation not seen in cells grown at atmospheric pressure. Cells grown under pressure demonstrated reduced growth rates, increased fibronectin production, and abnormal morphologies similar to fibroblasts isolated from venous ulcers. This study suggests that pressure elevations (like venous hypertension) can directly result in altered cell function and morphology that may contribute to the delayed wound healing seen in patients with venous ulcers. This model uses a pressurized incubator that may prove to be a valuable adjunct in studying the effects of venous hypertension.