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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Although myocutaneous flaps have evolved into a primary method for managing pressure sores, their value in reducing the recurrence rate by padding the pressure point is open to question. The use of muscle to cover a pressure point violates the normal soft-tissue coverage of a bony prominence and introduces a tissue that is exquisitely sensitive to ischemia. Clinical follow-up of patients who have had myocutaneous flaps for closure of pressure sores demonstrates almost total muscle atrophy. Although skin coverage is stable, the muscle bulk of a myocutaneous flap is not retained beyond one to two years. The long-term value of myocutaneous flaps in reducing the recurrence rate of pressure sores requires careful follow-up in major series of cases.
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PMID:Muscle coverage of pressure points--the role of myocutaneous flaps. 705 42

The histologic studies of the decubitus ulcer spectrum, which include blanchable erythema, nonblanchable erythema, decubitus dermatitis, decubitus ulcer, and the black eschar/gangrene reveal a dynamic process. The initial change occurs in the vessels of the papillary dermis. This is followed by necrosis of skin structures. The eschar/gangrene represents a full-thickness defect due either to prolonged ischemia and anoxemia or a sudden large vessel occlusion caused by shearing injury.
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PMID:Histopathology of the decubitus ulcer. 709 63

The primary etiologic factor in the production of pressure sores is considered to be pressure-induced ischemia with the threshold being 35mmHg for 2 hours. However, clinical evidence indicates that skin can withstand normothermic ischemia of 8 to 12 hours without necrosis. A detailed review of the literature indicates that previous experimental models are few in number and limited in clinical relevance. Therefore, a continuously monitored computer-controlled electromechanical pressure applicator was designed to produce pressure sores over the greater femoral trochanter of normal and paraplegic swine. Examination of the pressure site at 1 week revealed 3 groups of lesions: 1) muscle damage only, 2) muscle and deep dermis damage, and 3) full-thickness damage extending from bone to skin. A critical pressure-duration curve for the production of pressure sores is presented for normal swine. Muscle damage occurred at high pressure-short duration (500mmHg, 4 hours), whereas skin destruction required high pressure-long duration (800mmHg, 8 hours). On analysis, muscle is more sensitive than skin to the effects of pressure, and the initial pathologic changes occur in muscle. Skin breakdown did not occur with a pressure of 200mmHg for 15 hours, thus contradicting previous statements that pressure exceeding 35mmHg for 2 hours would cause ischemia with subsequent tissue necrosis resulting in a pressure sore. We hypothesis that normal tissue is far more resistant to pressure-induced ischemia that previously considered, and that the pressure-duration threshold for the production of pressure sores is lowered dramatically following changes in the soft tissue coverage due to paraplegia, infection, or repeated trauma.
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PMID:Etiologic factors in pressure sores: an experimental model. 730 43

Large open elbow fractures with extensive soft-tissue loss must be treated as an emergency. Vessels and nerves are often alvulsed. One stage reconstruction is very challenging. Ischemia of the distal part of the upper extremity is limited by a synthetic arterial shunt (SAS). After debridement, the authors install the SAS, then the complex procedure can begin. The authors purpose a new four-stage classification and prognostic factors. Debridement concerns crushed, devitalised soft and osteo-articular tissues. If it appears possible to salvage the hand and forearm with necessity of complex reconstructions (vessels, nerves, osteosynthesis, soft tissues) SAS is used. SAS was used 3 times on the group of large avulsions with ischemia (5 cases); it was quickly installed between the humeral and a distal artery and allowed section of the best distal artery for revascularisation. Seven external fixation devices allowed intra operative and post operative management of the wound. The coverage of these large, complex wounds was performed by the latissimus dorsi transposition flap (2 muscular and 5 musculo-cutaneous flaps). It should be considered the flap of choice. Local flaps, which include local skin transposition, muscle transposition or vascular axis, would be contra indicated in a wide zone of injury (the base of these local flaps are damaged by high energy trauma) or when distal ischemia is present because of arterial axis sacrifice. The dorsal decubitus position, the specific dissection of neurovascular pedicle proximally as far as the axillary artery, the muscular and cutaneous design can be used to cover anterior, posterior, internal and external parts of the elbow. Restoration of elbow function uses an innervated latissimus dorsi muscle (3 cases). If only coverage is wanted, this flap has significant advantages over local flaps and free transfer procedures when the recipient vessels are within the area of injury. Between the donor site and the recipient site, the muscular part of the latissimus dorsi flap is placed in an arm counterincision. It ensures closure of the elbow joint. Early progressive range of movement exercises can be performed.
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PMID:[Severe injuries of the elbow: emergency coverage and transient revascularization. Apropos of 13 cases over a 3-year period]. 771 72

17 parameters of vital activity (VA) were scanned in 35 female and 12 male dependent geriatric patients (mean age 81). These included mental testing, Barthel score, lung function, urinanalysis, creatinine clearance, Hb, albumin, globulin and electrolytes, skin-folds, locomotion, presence of IHD, hemodynamic state, continence, infections, WBC and lymphocyte count, pressure sores and dysphagia, 4 main templates of VA deterioration identified were: IHD, hemisyndrome (due to CVA), vegetative state (post-CVA) and senile dementia (SDAT). The IHD template was characterized by marked variations in VA, ending in death due to cardiac complications (pulmonary edema, ischemia, etc.). In the 3 other templates VA gradually deteriorated. Gradual declining VA allowed assessment of individual mortality prognosis. Assessment was by approximation of the computed exponent of the extrapolated VA curves; the longer the observation, the fewer the mistakes in assessment. Epidemiologic prognosis data of 48 dependent patients is described; mean age was about 81 years. Hospitalization mean was 853.5 +/- 601 days and for patients with dementia, 1158.6 +/- 622.7 days.
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PMID:[Assessment of vital activity in geriatric patients]. 781 43

Atypical decubital fibroplasia (FAD) occurs especially in elderly and physically debilited or immobilized patients. We report one observation which is peculiar due to the patient's young age and its circumstances. The painless mass is situated in hyperpressure areas (shoulder, posterior or lateral chest wall, sacrum). The lesion is situated in the deep subcutis and has ill defined limits; it is characterized by zones of fibrinoid necrosis and fibrosis and a prominent myxoid stroma. The differential diagnoses includes mesenchymatous malignant tumors and non neoplastic fibroblastic proliferations such as proliferative fasciitis and decubitus ulcer. The prominent underlying factor and the initial event contributing to its pathogenesis seems to be ischemia. Although some recurrent cases have been reported, FAD is a benign lesion whose treatment is surgical removal.
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PMID:[Atypical decubitus fibroplasia: a recent entity. Apropos of a case of an adolescent girl]. 867 61

Early complications following aortofemoral bypass grafting include acute limb ischemia, renal failure, bowel and spinal cord ischemia, and myocardial infarction. Although the literature recognizes these more common complications, we have found very few reports that raised the possibility of an anatomically determined, soft-tissue infarction as a complication of aortofemoral bypass grafting. Our plastic surgery service was consulted in August and October 1992 to examine 2 patients with soft-tissue complications following aortofemoral bypass grafting. Both patients were found to have complete gluteal infarction. Recognition of muscle infarction following aortofemoral grafting must be distinguished from postoperative pressure sores, since the muscle infarction requires prompt and thorough anatomic debridement to prevent in situ muscle liquefaction and sepsis.
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PMID:Gluteal infarction as a complication of aortofemoral bypass grafting. 898 80

The objective of this study was to examine and characterize limb-threatening lower extremity wound or soft tissue complications after coronary artery bypass (CABG) and determine risk factors for their cause. While minor wound problems of the leg after CABG are not uncommon, serious limb-threatening complications, though less frequent, do occur and are often de-emphasized in the surgical literature. A review of 1090 consecutive CABG procedures performed from January 1, 1995 through December 31, 1995 was instituted, which screened for limb-threatening lower extremity wound or soft tissue complications defined as wounds that: required additional surgery for treatment; prolonged the length of stay; or which required lengthy home health nursing for treatment. Minor lymph leaks, leg swelling, infections or wound problems treated as an outpatient were excluded. Of 1090 patients, 54 (5.0%) experienced a limb-threatening lower extremity complication. Complications were categorized as vein harvest incision non-healing (n = 36, 66.7%), decubitus ulceration (n = 11, 20.4%), forefoot ischemia/embolization (n = 10, 18.5%), groin hematoma/abscess (n = 6, 11.1%), severe cellulitis (n = 3, 5.6%), or a combination (n = 12, 22.2%). Statistically significant risk factors by univariate and bivariate analysis for a complication included older age (68 years vs 62 years, p = 0.007), female sex (57% vs 28%, p < 0.001), diabetes (57% vs 33%, p = 0.005) and longer pump time (129 min vs 114 min, p = 0.009). These complications necessitated five major lower extremity amputations and nine revascularization procedures. Chronic lower extremity ischemia from peripheral vascular disease (PVD) was a major contributing factor for the development of wounds in at least 23 (42.6%) of these patients, though suspected in only 10 (43.5%) preoperatively. A non-healing vein harvest incision below the knee of a patient retrospectively found to have inadequate distal circulation for healing occurred in 17 (31.5%) of the total 54 cases. It was concluded that non-healing vein incisions, decubitus ulcers and forefoot ischemic lesions frequently occurring in older diabetic females with undetected pre-existing PVD, comprise the majority of limb-threatening leg complications after CABG. Nearly one-third of the complications may have been avoided had the vein harvest incision not been made at the ankle of a patient with unappreciated PVD.
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PMID:An analysis of limb-threatening lower extremity wound complications after 1090 consecutive coronary artery bypass procedures. 1040 54

This study describes alterations in skin perfusion in response to step increases in surface pressure, before and after long-term (5 hr) exposure to pressure-induced ischemia. A provocative test was developed in which surface pressure was increased in increments of 3.7 mmHg until perfusion reached an apparent minimum by a computer-controlled plunger that included a force cell, a laser Doppler flowmeter to determine perfusion, and a thermistor to monitor skin temperature. Force was applied to the greater trochanters of adult male fuzzy rats. Skin perfusion (n=7) initially increased with low levels of surface pressure (up to 13.9+/-1.9 mmHg) and then decreased with further increases in pressure, reaching minimum (zero) perfusion at 58.2+/-3.64 mmHg. After pressure release, reactive hyperemia (3 x normal) was observed, with levels returning to normal within 15-30 min. The provocative test was then applied after a 5-hr ischemic episode (produced by 92 mmHg) and 3 hr of recovery. A comparison of responses between stressed and unstressed skin revealed: elevated (63%) control perfusion levels; loss of the initial increase in perfusion with low levels of increasing pressure; a depression (45%) in the hyperemic response with delayed recovery time; and a decrease (54%) in amplitude of low frequency (<1 Hz) rhythms in skin perfusion. Skin surface temperature gradually increased both during the control period and the period of incremental increases in surface pressure (total DT=3.3 degrees C). The results suggest a compromised vasodilator mechanism(s). The provocative test developed in this study may have clinical potential for assessing tissue viability in early pressure ulcer development.
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PMID:Skin perfusion responses to surface pressure-induced ischemia: implication for the developing pressure ulcer. 1066 27

Two complementary techniques were employed to assess the soft tissue response to applied pressure. The noninvasive methods involve the simultaneous measurement of the local tensions of oxygen and carbon dioxide (tcPO2 and tcPCO2) and the collection and subsequent analysis of sweat collected from the sacrum, a common site for the development of pressure sores. All tests were performed on able-bodied subjects. Results have indicated that oxygen levels (tcPO2) were lowered in soft tissues subjected to applied pressures of between 40 (5.3 kPa) and 120 mmHg (16.0 kPa). At the higher pressures, this decrease was generally associated with an increase in carbon dioxide levels (tcPCO2) well above the normal basal levels of 45 mmHg (6 kPa). There were also considerable increases, in some cases up to twofold, in the concentrations of both sweat lactate and urea at the loaded site compared with the unloaded control. By comparing selected parameters, a threshold value for loaded tcPO2 was identified, representing a reduction of ~60% from unloaded values. Above this threshold, there was a significant relationship between this parameter and the loaded/unloaded concentration ratios for both sweat metabolites. These parameters may prove useful in identifying those subjects whose soft tissue may be compromised during periods of pressure ischemia.
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PMID:Establishing predictive indicators for the status of loaded soft tissues. 1135 87


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