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Biomedical subjects

G A Holloway

Publications and source records attributed to G A Holloway.

At least 19 recordsLinked to original sources
PubMed2006

The effect of pressure loading on the blood flow rate in human skin.

The effect of pressure on the blood flow in skin is of considerable clinical interest. Methods are described for the estimation of skin blood flow from the disappearance rate of an injection of 133Xe in saline. The flow rate may be monitored for a period long enough to establish the normal flow and the reduced flow resulting from a constant pressure load. Initial results indicate that the flow is reduced greatly by pressures up to 10 mmHg. This result is interpreted as a demonstration of an auto regulatory mechanism of skin blood flow. Above 30 mmHg the flow continues to decrease essentially to zero as systolic pressure is approached.

Journal Article↗
PubMed1997

Laser Doppler evaluation of burned hands predicts need for surgical grafting.

Management of deep dermal hand burns represents a difficult clinical problem for the burn team because bedside estimation of burn depth is unreliable. Early identification of full-thickness injury and prolonged healing times might result in the decision to perform surgical excision of eschar and skin grafting of the wounds. Such a strategy may improve overall functional and cosmetic results of hand burn treatment. This report concerns a 2-year study of 31 patients with 43 burned hands using the LD6000 helium-neon laser Doppler flowmeter. After obtaining informed consent, burned areas of the hand were evaluated on days 1, 3, and 5 after burn. Results were reported as flow (mV), representing the quantity of moving erythrocytes multiplied by erythrocyte velocity in the capillary tissue. The reported volume in percentage of Doppler-shifted light represented only the quantity of moving erythrocytes. Median flow values in nongrafted hands were 150 mV; in those requiring skin grafts, median flow values were 89 mV. Flow values were significantly greater in nongrafted compared with grafted hand burns on days 1 and 5. Volume values were not associated with whether or not grafting was performed. Median volume values, however, did allow determination of whether the burns would spontaneously heal within 15 days (high group) or if a mean of 42 days would be required (low group). Functional and cosmetic outcomes were determined by retrospective chart review, which revealed comparable results regardless of grafting and regardless of short or prolonged healing times. Laser Doppler flowmetry may serve as a valuable adjunct to the prediction of the need for grafting and time to wound closure. Standardization of flowmetry data and techniques of evaluation are desirable. Spontaneous healing should be the goal in the majority of deep dermal hand burns.

Adult↗
PubMed1996

TcPO2 as an accurate predictor of therapy in limb salvage.

One hundred forty-seven consecutive patients with limb-threatening acute diabetic pedal sepsis and/or chronic ischemia (Fontaine III/IV) were prospectively studied. Forty-four with palpable pulses underwent successful surgery (major or minor amputation, incision, and drainage) without further evaluation; 103 with decreased or absent pulses had baseline TcPO2 measurements. Fourteen patients with values > or = 30 mm Hg underwent major or minor amputation with 91% (13 of 14) healing success. Ninety patients with values < 30 mm Hg underwent arteriography with 98% (87 of 89) showing significant disease. Of these, 22 did not undergo revascularization and only 50% (11 of 22) showed primary healing following minor amputation or debridement. Sixty-seven patients underwent 74 revascularization procedures; 95% (64 of 67) showed improvement of TcPO2 > 30 mm Hg and of these, 91% (58 of 64) had healing of minor amputation or debridement sites (p < 0.05). TcPO2 measurements may be used to direct therapy because they have been shown to accurately predict the presence of significant vascular disease, its appropriate correction by means of revascularization, and the success of major or minor amputations with or without revascularization.

Algorithms↗
PubMed1996

Arterial ulcers: assessment and diagnosis.

Arterial ulcers occur because of inadequate perfusion of skin and subcutaneous tissue at rest. Arterial occlusive disease, common among smokers, diabetics and the elderly, can lead to claudication, rest pain and gangrene, in addition to localized ulceration. Other processes, such as venous stasis, pressure, trauma, and vasculitis, can also cause ischemia. However, a thorough patient history and physical assessment can help discriminate between ischemic ulcers caused by arterial disease and other types of ulcers. The key to the diagnosis of arterial occlusive disease is the patient history. Pain while walking is the most common presenting complaint and can indicate intermittent claudication. Physical assessment should include both a general exam, looking for problems relating to lungs, heart and nervous system, and a focused exam of the affected extremities and arterial pulses. Vascular laboratory findings can also help confirm a diagnosis of arterial ischemic ulceration. The key to treatment is improvement in the vascular perfusion to the affected area. Surgical revascularization is the mainstay of treatment, with some interventional procedures becoming accepted. Medical options, in addition to correction of underlying medical problems, include good wound and supportive care, but pharmaceutical interventions have generally not proven effective, and should be considered only if interventional procedures are not possible. With an adequate blood supply reestablished, most arterial ulcers will progress to healing unless there are complicating factors.

Arterial Occlusive Diseases↗
PubMed1994

Spinal cord stimulation for relief of ischemic pain in end-stage arterial occlusive disease.

A total of 41 patients with end-stage arterial occlusive disease not treatable by surgery were enrolled in a study after implantation of a spinal cord stimulator. To date, a total of 25 patients have been followed up to 6 months after surgery. Patients were classified as grade I to grade III based on the scale developed by the Ad Hoc Committee on Reporting Standards, Society for Vascular Surgery/Society for Cardiovascular Surgery (1986). Sixty-seven percent of patients with rest pain who did not have ulcers (grade II) were successfully treated with a spinal cord stimulator. The success rate among patients who had rest pain and foot lesions was only 38%. Failure is defined as foot amputation or heroic bypass surgery. This study was conducted at six centers in North America.

Adult↗
PubMed1992

Randomized prospective double-blind trial in healing chronic diabetic foot ulcers. CT-102 activated platelet supernatant, topical versus placebo.

OBJECTIVE: To assess the efficacy of topically applied CT-102 APST for treating diabetic neurotrophic foot ulcers. RESEARCH DESIGN AND METHODS: Thirteen patients entered a randomized, double-blind trial of topically applied CT-102 APST vs. placebo (normal saline) gauze dressings for the treatment of nonhealing diabetic neurotrophic foot ulcers. CT-102 APST (Curative Technologies, Setauket, NY) was prepared from homologous platelets and contained multiple growth factors including PDGF, PDAF, EGF, PF-4, TGF-beta, aFGF, and bFGF. Inclusion criteria for subjects included diabetes, ulcer of > 8 wk duration, peri-wound transcutaneous oxygen tension > 30 mmHg, platelet count > 100,000/mm3, and no wound infection. Wounds were excised before entry and were > 700 mm3 but < 50,000 mm3 in volume, < 100 cm2 in area, and involved subcutaneous tissue. RESULTS: In the CT-102 group, 5 of 7 ulcers were healed (100% epithelialized) by 15 wk, but only 1 of 6 ulcers was healed by 20 wk with placebo (P < 0.05). Average percent reduction in ulcer area at 20 wk was 94% for CT-102 vs. 73% for placebo. Daily reduction in ulcer volume was 73.8 +/- 42.4 mm3/day (mean +/- SE) for CT-102 vs. 21.8 +/- 8.1 mm3/day for placebo (P < 0.05). Daily reduction in ulcer area was 6.2 +/- 1.8 mm2/day for CT-102 vs. 1.8 +/- 0.4 mm2/day for placebo (P < 0.05). CONCLUSIONS: CT-102 significantly accelerated wound closure in diabetic leg ulcers when administered as part of a comprehensive program for the healing of chronic ulcers.

Chronic Disease↗
PubMed1992

A comparison of wound environments.

A comparison of a system of moist wound dressings to traditional normal saline wet-to-dry dressings was conducted on OB/GYN patients with open abdominal incisions. The moist wound products included in this study were a hydrogel (Intrasite Gel) and a foam wound cavity filler (Allevyn), manufactured by Smith & Nephew United, Inc. of Largo, FL, and a transparent cover (Bioclusive), manufactured by Johnson & Johnson Medical, Inc. of Arlington, TX. The results indicated that those incisions treated with the moist wound environment dressings experienced fewer complaints of pain, a decrease in healing time and a significant cost savings.

Adolescent↗
PubMed1990

Effect of internal mammary artery mobilization on sternal blood flow.

Use of the internal mammary artery as a conduit for coronary artery bypass has enhanced this procedure in terms of prolonged graft patency. An earlier warning that use of both arteries would devascularize the sternum was based on postmortem radiologic imaging. This was complemented by a subsequent animal study employing isotopic microspheres. In the present clinical study, laser Doppler flowmetry was adapted to identify changes in blood supply to the left half of the divided manubrium sternum during separation of the left internal mammary artery from its chest wall attachment. Our finding of continued blood flow after this event suggests that complete devascularization of the sternum does not take place. Quality of sternal bone and surrounding tissues and clinical indications should remain as factors influencing use of one or both internal mammary arteries.

Humans↗
PubMed1989

Prevention of amputation by diabetic education.

This prospective randomized study evaluated the influence of a simple education program on the incidence of lower extremity amputation in diabetic patients. Two hundred three patients were randomized into two groups: Group 1, education (103 patients, 203 limbs) and Group 2, no education (100 patients, 193 limbs). There were no significant differences in medical management or clinical risk factors between the two groups. The amputation rate was three times higher in Group 2 (21 of 177 limbs versus 7 of 177 limbs; p less than or equal to 0.025), the ulceration rate was three times higher in Group 2 (26 of 177 limbs versus 8 of 177 limbs; p less than or equal to 0.005), and there was no difference in the overall incidence of infection (2 of 177 limbs). Overall success in Group 1 was highly significantly different from Group 2 (160 of 177 limbs versus 128 of 177 limbs; p less than or equal to 0.0005). This study demonstrated that a simple education program significantly reduced the incidence of ulcer or foot and limb amputation in diabetic patients.

Amputation, Surgical↗
PubMed1989

Interval insertion of an intrauterine contraceptive device following cesarean section.

Two previous studies of interval insertion of intrauterine contraceptive devices (IUCD) in women with previous cesarean delivery produced conflicting results. We studied the first and subsequent segment IUCD performance in 215 women with one or more cesarean deliveries. All the insertions were performed by doctors in the outpatient department of the hospital. The follow-up rate at 6 months was over 80%. There was a higher than expected expulsion rate of 19 per 100 insertions in the first 12 months, in both the first and subsequent segments. Other IUCD related problems were in keeping with expectations. The IUCD nonetheless remains a useful contraceptive option for these women.

Adult↗
PubMed1989

Multicenter trial of cadexomer iodine to treat venous stasis ulcer.

In a crossover study designed to judge the efficacy of the topical polymeric starch iodophore, cadexomer iodine, in accelerating the healing of venous stasis ulcers, 75 patients were prospectively randomly assigned to receive either cadexomer iodine or standard treatment. The control treatment consisted of a standard saline wet-to-dry compressive dressing. The patients improved with either treatment: ulcers healed more than twice as rapidly using cadexomer iodine (n = 38) as with standard therapy (n = 37) (P = .0025). Ulcers treated with cadexomer iodine showed trends toward less pain, exudate, pus, and debris, and a more rapid development of granulation tissue. Twelve patients crossed over from control treatment to the use of cadexomer iodine because of a failure to heal, but no patients switched to control therapy from the use of cadexomer iodine (P = .01). Except for occasional mild local burning in wounds treated with cadexomer iodine, no adverse effects were noted with either regimen.

Adult↗
PubMed1988

Flow recovery and vasoconstriction following microvascular anastomosis.

A variety of factors may limit blood flow recovery in free flaps. In this study one of these factors, vasoconstriction, and its consequences was investigated. Blood flow recovery at the skin level following microvascular anastomosis was evaluated in the rat orthotopic groin free flap model using a laser Doppler velocimeter. In a study of 41 rats, measurements of external vessel diameter were made using a standard machinist's drum micrometer. After each flap was raised and the anastomoses performed, the field was flooded with either saline, 2% lidocaine, or 0.75% bupivacaine (Marcaine). The vascular clamps were released and measurements of flow were recorded as a percentage of the control value. In the saline-control group, it was found that flow gradually recovered to 91% of the preoperative value in an average time of 5.7 minutes. Six of 12 vessels in this group were found to have measurable spasm of the pedicle. In the lidocaine-treated group, flow recovered to 93% of the preoperative value in an average of 5.0 minutes. Two of 15 vessels had measurable spasm. In the Marcaine-treated group, flow recovered to 94% of the preoperative value in an average of 5.1 minutes. Three of 14 vessels showed measurable spasm. The final level of flow recovery showed no statistical difference in any of these groups whether or not spasm was present. We therefore conclude that, in this model, alteration in the diameter of the vascular pedicle as a consequence of performing a microvascular anastomosis affects only the time it takes to achieve ultimate recovery of flow but does not affect its final level.

Anastomosis, Surgical↗
PubMed1984

The relationship of transcutaneous PO2 and laser Doppler measurements in a human model of local arterial insufficiency.

Transcutaneous PO2 and laser Doppler measurements were made over areas of unheated and heated skin of the feet of normal volunteers. Stepwise elevation of the foot above the level of the heart systematically reduced the local arterial pressure and, thus, the local arteriovenous gradient in these areas. Results indicated that transcutaneous PO2 and laser Doppler measurements reflect changes in local arteriovenous gradient when made over areas of warmed skin, but not unwarmed skin. Comparison of skin surface and subcutaneous temperatures obtained with two heater types revealed the importance of heater configuration. Results confirm a previously hypothesized nonlinear relationship between transcutaneous PO2 and local cutaneous blood flow and indicate that a transcutaneous PO2 reading of zero may be obtained in the presence of significant local cutaneous blood flow.

Arterial Occlusive Diseases↗