Optimization of shared autonomy vehicle control architectures for swarm operations.

The need for greater capacity in automotive transportation (in the midst of constrained resources) and the convergence of key technologies from multiple domains may eventually produce the emergence of a "swarm" concept of operations. The swarm, which is a collection of vehicles traveling at high speeds and in close proximity, will require technology and management techniques to ensure safe, efficient, and reliable vehicle interactions. We propose a shared autonomy control approach, in which the strengths of both human drivers and machines are employed in concert for this management.

Clinical and radiographic findings of a sliding inguinoscrotal hernia containing the urinary bladder.

Large sliding inguinal hernias involving the urinary bladder are rare. We present the relevant clinical data, radiographic images, and the intraoperative findings of a sliding inguinoscrotal herniation of the urinary bladder. A 67-year-old male presented with a scrotal mass and the need to manually compress his scrotum in order to void.

A network model of H5N1 avian influenza transmission dynamics in domestic cats.

Naturally occurring cases of influenza in cats owing to the H5N1 strain have been reported in several countries. A cat reservoir of H5N1 in the United States could provide an environment for zoonotic disease spread to humans. This scenario was the impetus to develop a model to study potential transmission of H5N1 virus in domestic cats utilizing information on cat ownership and cat-cat interaction patterns, in addition to biological properties of the virus.

Bacillus Calmette-Guerin. Is monthly maintenance an option for transitional cell carcinoma of the bladder?

Purpose: Recently, a Southwest Oncology Group study (SWOG 8507) demonstrated increased efficacy for a bacillus Calmette-Guerin (BCG) maintenance (mtce) program (3 weekly treatments at 3 months, 6 months, and every 6 months thereafter for 3 years) following 6 weekly instillations with BCG as compared to no mtce ("6+3" protocol). The remarkable results from the mtce arm were unfortunately accompanied by grade 3 or 4 toxicity in 26%. In fact; only 16% of the patients in the maintenance arm received BCG at each of the 7 prescribed courses.

Idiopathic pedunculated mural thrombus of the nonaneurysmal infrarenal aorta presenting with popliteal embolization: two cases treated with thrombolytic therapy.

The source of emboli to large or medium sized arteries is most commonly the heart; occasionally, it is an aortic aneurysm. The unusual embolic source of aortic mural thrombus in an otherwise minimally diseased aorta has been infrequently reported, and the etiology and management of this entity are not well defined. We describe two cases of infrarenal aortic mural thrombus treated with thrombolytic therapy and review the published experience with this entity.

Five-step protocol for carotid endarterectomy in the managed health care era.

Background: We developed a protocol combining 5 cost-effective strategies to determine whether elective carotid endarterectomy (CEA) could be performed safely without adversely affecting well-established low morbidity and mortality rates and with significant hospital cost savings.

Methods: Between April 1, 1995, and December 31, 1996, 109 of 141 patients were prospectively enrolled as candidates into a 5-step CEA protocol: (1) duplex ultrasonography (DU) performed at an accredited vascular laboratory as the sole diagnostic carotid preoperative study, (2) admission the day of operation, (3) cervical block anesthesia to eliminate intraoperative electroencephalogram monitoring, (4) transfer from the recovery room after a 4-hour observation period to the vascular ward, and (5) discharge the first postoperative morning. The other 32 patients were excluded from analysis; 16 patients were treated by vascular surgeons not participating in the protocol, 9 were treated concomitantly for other medical problems, and 7 were admitted emergently.

Revision of failing lower extremity bypass grafts.

Background: Color-duplex ultrasound (CDU) surveillance of arterial bypass grafts has been validated, but the natural history of "failing" grafts remains poorly defined. Our purpose was to compare failing grafts having prophylactic revision with those that did not.

Methods: Postoperative duplex surveillance was performed in an accredited vascular laboratory for all lower extremity bypass grafts performed at a single institution.

Value of an endovascular suite in the operating room.

The purpose of this study is to describe the advantages and value of an endovascular suite in the operating room from a vascular surgeon's perspective. All endovascular procedures were performed in a specially equipped operating room by vascular surgeons using digital fluoroscopic imaging equipment. Between January 1, 1994 and August 31, 1996, intraoperative balloon angioplasties were attempted by vascular surgeons in 102 patients with insertion of 22 stents.

The natural history of "failing" arterial bypass grafts in a duplex surveillance protocol.

Though color duplex ultrasonography (CDU) can identify threatened arterial bypass grafts, the natural history of grafts predicted to fail is not known. We examined patency of "failing grafts" followed by CDU for prolonged periods without intervention. A graft was defined as failing if there was elevation of the peak systolic flow velocity (PSFV) to a ratio of three times the PSFV in the adjacent graft, or if PSFV was less than 45 cm/sec throughout the graft.

Do distal arteriovenous fistulae improve patency rates of prosthetic infrapopliteal arterial bypasses?

We retrospectively analyzed if distal anastomotic adjunctive arteriovenous fistulae (AVF) improved patency rates of prosthetic bypasses to infrapopliteal arteries. Between July 1, 1991 and June 30, 1996, we performed 43 polytetrafluoroethylene (PTFE) bypasses to infrapopliteal (19 peroneal, 13 anterior tibial, 11 posterior tibial) arteries. All bypasses were performed for limb salvage when autologous vein was not available for a conduit.

Is balloon angioplasty indicated for "short" stenoses of failing vein grafts?

Previous reports have suggested "short" focal stenoses in peripheral vein grafts (PVGs), namely less than 2 cm long, can be successfully balloon dilated with good long-term patency rates. We questioned if enthusiasm for balloon angioplasty of these lesions in failing PVGs is warranted. Between August 1, 1993 and December 31, 1996, we performed balloon angioplasty of "short" stenoses in 19 PVGs in 16 patients.

Selective use of duplex ultrasound to replace preoperative arteriography for failing arterial vein grafts.

Purpose: In an effort to minimize costs and patient discomfort, we determined whether duplex ultrasound (DU) could selectively replace preoperative arteriography performed in the radiology suite to diagnose failing arterial bypass grafts (FABs) constructed of autogenous vein.

Methods: Between January 1, 1994, and December 31, 1996, we treated 106 FABs. Graft revision solely on the basis of DU was performed only if a focal stenosis was clearly identified in the graft (peak systolic velocity [PSV] > 300 cm/sec, ratio of adjacent PSVs > 3.

Use of arm and lesser saphenous vein compared with prosthetic grafts for infrapopliteal arterial bypass: are they worth the effort?

Purpose: Arm and lesser saphenous veins (ALSVs) are generally considered to be the best alternative for infrapopliteal arterial bypass grafts when greater saphenous vein is not available. The need for additional incisions and repositioning of the patient, along with occasional use of general anesthesia for arm vein harvesting, led to our perception that the use of ALSVs increased operative time and possibly patient discomfort. Therefore, we compared the outcome of ALSVs with that of prosthetic infrapopliteal arterial bypass procedures performed at our hospital.

Same-day admissions and other cost-saving strategies for elective aortoiliac surgery.

Purpose: We retrospectively analyzed whether same-day admissions and other resource utilization methods for patients undergoing elective infrarenal aortoiliac surgery (AoIS) were safe and cost-effective.

Methods: Morbidity and mortality rates and costs were compared between 71 patients admitted before the day of surgery (group I) and 57 patients admitted the day of surgery (group II) who underwent elective AoIS between July 1, 1992, and December 31, 1995. After January 1, 1994, a concerted effort was made to decrease hospital costs by performing out-patient preoperative assessment, admitting patients the morning of surgery, and planning early discharge through implementation of clinical pathways.

Thrombolytic and endovascular treatment of peripartum iliac vein thrombosis: a case report.

This case report details the multidisciplinary treatment of peripartum left iliac vein thrombosis using percutaneous catheter-directed urokinase thrombolysis and balloon thromboplasty. Enhanced chances for long-term patency and the normalization of venous function make these minimally invasive procedures accepted options for the treatment of iliofemoral deep venous thrombosis in selected peripartum patients.

Role of nursing personnel in implementing clinical pathways and decreasing hospital costs for major vascular surgery.

Collaboration with key nursing personnel is essential to successfully implement clinical pathways, establish a dedicated vascular wing, and achieve significant hospital cost savings while still maintaining quality care with low morbidity and mortality rates. Key nursing personnel met once a month during a 1-year period with vascular surgeons, hospital administrators, and health care advisors to plan strategies to develop clinical pathways and establish a dedicated vascular ward. The pathways were then implemented.

Duplex ultrasonography to diagnose failing arterial prosthetic grafts.

Background: Although several reports have documented the usefulness of a surveillance program with duplex ultrasonography (DU) to diagnose failing autologous vein bypasses, the effectiveness of DU to detect failing arterial prosthetic grafts has not been confirmed. We attempted to determine whether our program, which included DU and other noninvasive techniques (NonDU), was useful for this purpose.

Methods: Between July 1, 1991, and September 30, 1994, 85 prosthetic bypasses in 59 patients performed for lower extremity ischemia were entered into a graft surveillance protocol.

Management and outcome of infrapopliteal arterial graft infections with distal graft involvement.

Purpose: The purpose of this study was to determine the outcome of patients with infrapopliteal artery graft infections (InfraPopGIs) who presented with graft infection distal to the popliteal artery.

Patients And Methods: Between July 1, 1979 and June 30, 1994, 27 patients presented with infrapopliteal artery graft infections (18 polytetrafluoroethylene [PTFE], 9 autologous vein). The infection involved the anastomosis in 22 cases (8 anterior tibial, 8 posterior tibial, 4 peroneal, 2 dorsalis pedis arteries) and was localized to the body of the graft in 5 cases (4 calf, 1 ankle).

Safety and cost-efficiency of 24-hour hospitalization for carotid endarterectomy.

The safety and cost savings of carotid endarterectomy (CEA) were determined with guidelines developed after vascular "critical pathways" were implemented. Using these guidelines, our goal was to admit patients the day of surgery and to discharge them the next morning. Morbidity, mortality, readmission rates, same-day admissions, duration of stay, and hospital costs were compared between patients undergoing CEA who were electively admitted between September 1, 1992 and August 31, 1993 (group 1) and January 1, 1994 and March 31, 1995 (group 2).

Congenitally absent inferior vena cava presenting in adulthood with venous stasis and ulceration: a surgically treated case.

Absence of the inferior vena cava (IVC) is an uncommon congenital abnormality. Symptoms of lower extremity venous insufficiency resulting from this anatomic abnormality have been reported only once in the English literature, and no experience with surgical treatment of this condition has been published. We report the case of an otherwise healthy 41-year-old man with an 18-month history of severe venous insufficiency involving the right leg manifested by extensive ulceration that did not respond to aggressive conservative treatment.

Differences in early versus late extracavitary arterial graft infections.

Purpose: The purpose of this report was to determine differences in presentation, bacteriology, management, and outcome of early (EGIs) versus late extracavitary arterial graft infections (LGIs).

Methods: Between July 1, 1979, and June 30, 1994, we treated 141 patients with infected extracavitary arterial grafts (112 prosthetic, 29 vein) with selective partial or complete graft preservation.

Results: A total of 99 (70%) EGIs (< 2 months) and 42 (30%) LGIs (4 to 96 months) were involved.

Impact of clinical pathways on hospital costs and early outcome after major vascular surgery.

Purpose: The purpose of this study was to determine whether major vascular surgery could be performed safely and with significant hospital cost savings by decreasing length of stay and implementation of vascular clinical pathways.

Methods: Morbidity, mortality, readmission rates, same-day admissions, length of stay, and hospital costs were compared between patients who were electively admitted between September 1, 1992, and August 30, 1993 (group 1), and January 1 to December 31, 1994 (group 2), for extracranial, infrarenal abdominal aortic, and lower extremity arterial surgery. For group 2 patients, vascular critical pathways were instituted, a dedicated vascular ward was established, and outpatient preoperative arteriography and anesthesiology-cardiology evaluations were performed.