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Biomedical subjects

S Harms

Publications and source records attributed to S Harms.

11 recordsLinked to original sources
PubMed2001

Hematoma-directed ultrasound-guided breast biopsy.

OBJECTIVE AND SUMMARY BACKGROUND DATA: The standard technique for removal of nonpalpable breast lesions is needle localization breast biopsy. Because traumatic hematomas can often be seen with ultrasound, the authors hypothesized that iatrogenically induced hematomas could be used to guide the excision of nonpalpable lesions using ultrasound. METHODS: Twenty patients with nonpalpable breast lesions detected by magnetic resonance imaging only were enrolled in this single-institution trial, approved by the institutional review board. A hematoma consisting of 2 to 5 mL of the patient's own blood was injected into the breast to target the nonpalpable lesion. Intraoperative ultrasound of the hematoma was used to direct the excisional biopsy. RESULTS: The average age of women was 53.8 +/- 10 years. Ninety-five percent of lesions detected by magnetic resonance imaging were localized by hematoma injection. All the hematomas used to recognize targeted lesions were identified at surgery by ultrasound and removed without complication. Eight (40%) of the lesions were malignant, with an average tumor size of 12 +/- 6 mm (range 4-25). The remaining 12 lesions (60%) comprised papillomas, sclerosing adenosis, radial scar, fibroadenoma, and areas of atypical ductal hyperplasia. CONCLUSION: The results of this pilot study show the effectiveness of hematoma-directed ultrasound-guided breast biopsy for nonpalpable lesions seen by magnetic resonance imaging. This new procedure is potentially more comfortable for the patient because no wire or needle is left in the breast. It is technically faster and easier because ultrasound is used to visualize directly the location of the hematoma at surgery and to confirm lesion removal in the operating room by specimen ultrasound. The hematoma can be placed several days before biopsy, easing scheduling, and without fear of the migration that may occur with needle localization. This method may have ready application to mammographically detected lesions.

Adult↗
PubMed2000

Biologically variable ventilation increases arterial oxygenation over that seen with positive end-expiratory pressure alone in a porcine model of acute respiratory distress syndrome.

OBJECTIVES: We compared biologically variable ventilation (BVV) (as previously described) (1) with conventional control mode ventilation (CV) in a model of acute respiratory distress syndrome (ARDS) both at 10 cm H2O positive end-expiratory pressure. DESIGN: Randomized, controlled, prospective study. SETTING: University research laboratory. SUBJECTS: Farm-raised 3- to 4-month-old swine. INTERVENTIONS: Oleic acid (OA) was infused at 0.2 mL/kg/hr with FIO2 = 0.5 and 5 cm H2O positive end-expiratory pressure until PaO2 was < or =60 mm Hg; then all animals were placed on an additional 5 cm H2O positive end-expiratory pressure for the next 4 hrs. Animals were assigned randomly to continue CV (n = 9) or to have CV computer controlled to deliver BVV (variable respiratory rate and tidal volume; n = 8). Hemodynamic, expired gas, airway pressure, and volume data were obtained at baseline (before OA), immediately after OA, and then at 60-min intervals for 4 hrs. MEASUREMENTS AND MAIN RESULTS: At 4 hrs after OA injury, significantly higher PaO2 (213+/-17 vs. 123+/-47 mm Hg; mean+/-SD), lower shunt fraction (6%+/-1% vs. 18%+/-14%), and lower PaCO2 (50+/-8 vs. 65+/-11 mm Hg) were seen with BVV than with CV. Respiratory system compliance was greater by experiment completion with BVV (0.37+/-0.05 vs. 0.31+/-0.08 mL/cm H2O/kg). The improvements in oxygenation, CO2 elimination, and respiratory mechanics occurred without a significant increase in either mean airway pressure (14.3+/-0.9 vs. 14.9+/-1.1 cm H2O) or mean peak airway pressure (39.3+/-3.5 vs. 44.5+/-7.2 cm H2O) with BVV. The oxygen index increased five-fold with OA injury and decreased to significantly lower levels over time with BVV. CONCLUSIONS: In this model of ARDS, BVV with 10 cm H2O positive end-expiratory pressure improved arterial oxygenation over and above that seen with CV with positive end-expiratory pressure alone. Proposed mechanisms for BVV efficacy are discussed.

Analysis of Variance↗
PubMed2000

Biologically variable or naturally noisy mechanical ventilation recruits atelectatic lung.

Biologically variable mechanical ventilation (Vbv)-using a computer-controller to mimic the normal variability in spontaneous breathing-improves gas exchange in a model of severe lung injury (Lefevre, G. R., S. E. Kowalski, L. G. Girling, D. B. Thiessen, W. A. C. Mutch. Am. J. Respir. Crit. Care Med. 1996;154:1567-1572). Improved oxygenation with Vbv, in the face of alveolar collapse, is thought to be due to net volume recruitment secondary to the variability or increased noise in the peak inspiratory airway pressures (Ppaw). Biologically variable noise can be modeled as an inverse power law frequency distribution (y approximately 1/f(a)) (West, B. J., M. Shlesinger. Am. Sci. 1990;78:40-45). In a porcine model of atelectasis-right lung collapse with one-lung ventilation-we studied if Vbv (n = 7) better reinflates the collapsed lung compared with conventional monotonously regular control mode ventilation (Vc; n = 7) over a 5-h period. We also investigated the influence of sigh breaths with Vc (Vs; n = 8) with this model. Reinflation of the collapsed lung was significantly enhanced with Vbv-greater Pa(O(2)) (502 +/- 40 mm Hg with Vbv versus 381 +/- 40 mm Hg with Vc at 5 h; and 309 +/- 79 mm Hg with Vs; mean +/- SD), lower Pa(CO(2)) (35 +/- 4 mm Hg versus 48 +/- 8 mm Hg and 50 +/- 8 mm Hg), lower shunt fraction (9.7 +/- 2.7% versus 14.6 +/- 2.0% and 22.9 +/- 6.0%), and higher respiratory system compliance (Crs) (1.15 +/- 0.15 ml/cm H(2)O/kg versus 0.79 +/- 0.19 ml/cm H(2)O/kg and 0.77 +/- 0.13 ml/cm H(2)O/kg)-at lower mean Ppaw (15.7 +/- 1.4 cm H(2)O versus 18.8 +/- 2.3 cm H(2)O and 18.9 +/- 2.8 cm H(2)O). Vbv resulted in an 11% increase in measured tidal volume (VT(m)) over that seen with Vc by 5 h (14.7 +/- 1.2 ml/kg versus 13. 2 ml/kg). The respiratory rate variability programmed for Vbv demonstrated an inverse power law frequency distribution ( y approximately 1/f(a)) with a = 1.6 +/- 0.3. These findings provide strong support for the theoretical model of noisy end-inspiratory pressure better recruiting atelectatic lung. Our results suggest that using natural biologically variable noise has enhanced the performance of a mechanical ventilator in control mode.

Animals↗
PubMed1999

Assessing margin status.

As little time ago as 1991 the NIH Consensus conference could not agree on the need for negative margins. Today, negative margin status has become a prerequisite for BCT recognizing that positive margins impact negatively on local recurrence rates. The science of margin evaluation is fast becoming recognized to play a key role in providing patients with the opportunity for breast conservation therapy as well as the best possible cosmetic result. Preoperative factors that predict a greater likelihood of failure to obtain margins such as larger tumor size and positive lymph nodes are fixed and can only be dealt with by taking larger biopsies. RODEO-MRI can preoperatively predict probability of success or failure and can actual better define tumor dimensions and extent and help plan excisions. Use of intraoperative US may be a future tool used to facilitate the excision of non-palpable and possibly palpable tumors. Intraoperative pathological assessment should not be performed by frozen section but consideration given to cytological assessment so as to allow feedback to the surgeon intraoperatively as to which margin needs more attention. Finally, using all the above methods of obtaining negative margins, the surgeon may have the ability to impact the outcome of breast cancer surgery and recurrence.

Biopsy, Needle↗
PubMed1992

Breast MRI. The potentials and dangers: are you informed?

Breast MRI is a field that is rapidly emerging. The approaches to breast MRI technology and clinical utilization are highly variable. The viability of any selected technology should be fully understood before it is advocated as a solution for any clinical role. It is my opinion that all breast MR methods currently in use should undergo more clinical trials before they are employed for routine breast diagnosis. Before purchasing special breast imaging hardware, you should be shown proof of clinical capability that includes well controlled clinical trials, not just a pretty picture. The use of MRI for breast diagnosis is far different from other clinical applications. If MRI misses the meniscal tear, the patient will return with continued symptoms and eventually have appropriate treatment. If MRI falsely calls a meniscal tear, then the worst thing that will happen is a diagnostic arthroscopy which would have occurred if the patient had never had the MRI. If breast MRI detects an enhancing mass that cannot be confirmed by biopsy or any other imaging examination, there are two potential disastrous consequences: 1) Overzealous treatment could result in needless and permanent deformity. 2) The results of the MRI positive lesion are ignored and the patient may lose the opportunity for cure in a lesion confined to the breast. Until MRI directed biopsy capability is available, the clinical value of this examination is questionable. MRI may be used for the evaluation of possible free silicone from implant leaks. The ultimate role of MRI in this evaluation compared with sonography is uncertain.(ABSTRACT TRUNCATED AT 250 WORDS)

Breast Neoplasms↗
PubMed1987

Fluid-fluid levels in giant cell tumors of bone: report of two cases.

Fluid-fluid levels have been described in association with aneurysmal bone cysts, telangiectatic osteosarcoma, and a chondroblastoma. We report two cases of giant cell tumors of bone with fluid-fluid levels identified by computed tomography and, in one case, by magnetic resonance imaging. This finding has not previously been associated with giant cell tumors. The radiographic features of the fluid-fluid levels cannot be distinguished from those reported in other osseous neoplasms.

Adolescent↗