Perspectives from a surgeon turned hospital chaplain.
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Attitude of Health Personnel↗
Biomedical subjects
I B Faris
Publications and source records attributed to I B Faris.
The effects of carotid endarterectomy on ocular haemodynamics.
PURPOSE: To determine the profile of blood flow velocities and resistive indices in the ocular vessels of patients with atherosclerotic carotid disease and characterise the effect of endarterectomy on these parameters. METHODS: Following a preliminary study on healthy volunteers, ophthalmic colour Doppler ultrasound examinations were performed on 27 male and 11 female patients with carotid disease. These measurements were compared with central retinal artery perfusion pressures and intraoperative internal carotid artery stump pressures. RESULTS: Significant changes were seen on the endarterectomised side. The peak systolic velocity in the ophthalmic artery, and resistive indices in the ophthalmic artery, central retinal artery and nasal posterior ciliary artery, rose from pre-operative values. No correlation between colour Doppler ultrasound measurements and intraoperative internal carotid artery stump pressures was present. When compared with ophthalmodynamometry readings, a relationship was noted with maximum velocities in the central retinal vein. CONCLUSION: Carotid endarterectomy alters the haemodynamics in selected vessels of the ocular circulation as measured by colour Doppler ultrasound, but more work is required to determine the clinical utility of this investigative modality.
Adult↗
Arterial injury in the lower limb from blunt trauma.
BACKGROUND: The present study was performed to identify the factors associated with amputation in patients with blunt injuries to the lower limb associated with arterial injury. The ability of a scoring system to predict the outcome was tested. METHODS: There were 122 lower limb arterial injuries in 119 patients treated at the Royal Adelaide Hospital in the years 1962-1994. Prognostic factors considered were the site of the injury, the severity of the soft-tissue injury and shock, the presence of associated injuries and a description of the bone or joint injury. The mangled extremity severity score (MESS) was calculated retrospectively for each patient. RESULTS: The outcome was primary amputation in 27 patients, delayed amputation in 36 patients and limb salvage in 59 patients. The seven deaths were all due to associated injuries. Factors associated with amputation were the severity of shock and soft-tissue injury (P < 0.01), and tibial artery injury compared with more proximal injury (P < 0.001). Factors that did not affect outcome included delay before repair, method of fracture fixation, or performance of fasciotomy. Amputation was performed in 48/71 (68%) patients with Gustilo type-IIIC fractures of the tibia. Applying the MESS to our patients resulted in a positive predictive value (PPV) of 71%, a negative predictive value (NPV) of 84% and an overall accuracy of prediction of 75%. CONCLUSIONS: The major factor determining outcome was the severity of the soft-tissue injury. Progressive necrosis and infection was a major cause of late amputation. The MESS is not sufficiently precise to allow the decision regarding amputation to be made at the initial operation.
Accidents, Occupational↗
Transmetatarsal amputation for advanced forefoot tissue loss in elderly patients.
Transmetatarsal amputation is considered a useful procedure because it is more likely to preserve mobility than a major amputation. In this retrospective review of 33 consecutive transmetatarsal amputations for advanced tissue loss of the forefoot, a high revision rate to major amputation (18/33) was offset by a significantly greater chance of preserving independent mobility in patients whose heel was preserved (P = 0.01). There was no difference in the non-invasive test results, smoking or diabetes history, or in the age of those who healed or those who did not. Factors that may contribute to improved wound healing rates in the future include refinements in the use of non-invasive tests, improved wound care, and advances in techniques of revascularization.
Aged↗
Internal jugular vein thrombosis following carotid endarterectomy.
Internal jugular vein thrombosis (IJVT) is an uncommon condition, which is often not correctly diagnosed clinically. Diagnosis is readily made by duplex scan, computerized tomography with contrast or magnetic resonance imaging. A case of IJVT following carotid endarterectomy with intra-operative retraction of the internal jugular vein is reported.
Blindness↗
Femorocrural grafting and regrafting: does polytetrafluoroethylene have a role?
Between 1980 and 1988, 263 patients received 307 femorocrural bypass grafts. 180 were primary infrainguinal grafts, 106 secondary, 18 tertiary and three quaternary. Rest pain or tissue loss was the indication in 96% of cases. Outflow vessels were the tibioperoneal trunk (n = 34), posterior tibial artery (n = 115), peroneal artery (n = 89) and anterior tibial artery (n = 69). 88 primary vein grafts were completed. 201 polytetrafluoroethylene (PTFE) grafts were inserted (92 primary and 109 subsequent reconstructions). There were no direct PTFE to crural vessel anastomoses. A Miller cuff was used in the majority (n = 175). The three year primary patency for primary vein grafts (36%) was similar to primary PTFE grafts (29%), but significantly higher than subsequent PTFE grafts (20%) (p = 0.03). Three year foot salvage for primary vein grafts (65%) was similar to primary PTFE (64%), but significantly better than subsequent PTFE (42%) (p = 0.02). The results support both redo femorocrural grafting for critical ischaemia, as judged by foot salvage rates, and the use of PTFE with a distal vein cuff in primary and subsequent femorocrural reconstruction if autologous vein is not available.
Adult↗
Duplex ultrasound mapping of sites of deep to superficial incompetence in primary varicose veins.
Most patients undergoing treatment for primary varicose veins have only a clinical assessment or examination with a continuous wave Doppler. In this study duplex ultrasound was used to determine the site of deep to superficial reflux in 137 limbs of 96 patients presenting with primary varicose veins. The incidence of saphenopopliteal (22%) and perforator (28%) incompetence was higher than that in previous studies based on clinical examination. Only five limbs had deep venous incompetence at the popliteal level and three of these limbs had lipodermatosclerosis or ulceration. The saphenopopliteal junction was either absent or more than 10 cm from the knee joint in 13% of limbs. The information obtained from duplex scanning of patients with primary varicose veins facilitates surgical management and may lead to a lower recurrence rate.
Femoral Vein↗
A comparison of Doppler ankle pressures and skin perfusion pressure in subjects with and without diabetes.
Doppler ankle pressure measurements may be misleading in some patients because medial calcification has made the arteries of the leg incompressible. This problem is especially common in diabetics. Medical calcification that is not severe enough to make an artery clinically incompressible may cause an increased stiffness of the arterial wall that will limit the accuracy of Doppler ankle pressure measurements. A comparison of skin perfusion pressure, using an isotope technique, and Doppler ankle pressures was made in 226 subjects, diabetic and non-diabetic. Patients with incompressible arteries were excluded from the study. The slopes of the regression lines relating skin perfusion pressure to Doppler ankle pressure in diabetic and non-diabetic subjects were significantly different (P = 0.03). This result was consistent with the hypothesis that diabetic subjects have arteries that are less compressible than normal arteries and may make Doppler ankle pressure measurements in diabetic subjects misleading over the whole range of pressures recorded.
Ankle↗
Transcutaneous oxygen tension measurements in the assessment of limb ischaemia.
The measurement of transcutaneous oxygen tension (TcPO2) has been adapted for the assessment of the blood supply of the lower limb. This study was undertaken to determine the most useful means of expressing TcPO2 measurements. We studied 176 patients with peripheral vascular disease and/or diabetes and 34 normal volunteers. Approximately++ half of the patients studied had ulceration or gangrene of the foot. A comparison of three methods of expressing TcPO2 measurement for predicting presence of ulceration was made using ROCA analysis. The absolute value of TcPO2 on the dorsum of the foot was the best predictor of the presence of ulceration or gangrene. An absolute value of TcPO2 of 30 mmHg on the dorsum of the foot had a sensitivity of 42% and specificity of 91%. The sensitivity of the test was as good in diabetic patients as in non-diabetic patients.
Blood Gas Monitoring, Transcutaneous↗
Transcutaneous oxygen potentials in venous disease.
Abnormal levels of transcutaneous tissue oxygen tension (TcPO2) have been reported in venous disease but the most appropriate application of the technique to the study of venous disease is not clear. Patients with mild (superficial varicosities) and severe venous disease (ulcers and/or skin changes) and normal controls were studied. Four variables derived by measurement of TcPO2 were used for comparison between groups. The peak postischaemic response was reduced markedly in patients with severe venous disease and may be the most appropriate way of applying TcPO2 measurements to investigation of venous disease. The findings support the theory that a diffusion block to oxygen exists in severe venous disease.
Blood Gas Monitoring, Transcutaneous↗
Monitoring of heparin in vascular surgery.
In patients heparinized for surgery on the infrarenal aorta, the degree of anticoagulation by heparin of stasis blood (taken from below the aortic clamp) was compared with that obtained in circulating blood taken from a forearm artery. A measurement of activated partial thromboplastin time (APTT) was made on a venous blood sample taken from each patient before 5000 units of heparin was administered intravenously. Further measurements of APTT from static blood and from circulating arterial blood were made at 3, 15, 30, and 60 minutes after heparinization. Samples taken below the aortic clamp showed measurements of APTT lower than those from circulating arterial blood at 15, 30, and 60 minutes (p less than 0.05 paired Wilcoxon rank sum test). Current methods for administering and monitoring heparin may not provide an adequate degree of anticoagulation in static blood during vascular surgery. The consequences, if any, of inadequate anticoagulation in vascular surgery need further study.
Aged↗
Duodenal obstruction as the presenting symptom of aortic aneurysm.
Two patients with duodenal obstruction as the presenting symptom of an abdominal aortic aneurysm are reported. The increasing frequency of aortic aneurysm in an ageing population may make this rare cause of duodenal obstruction more common. Vomiting, abdominal pain, and weight loss are the common presenting, symptoms. This report includes only the third successful aortic replacement in these patients. Upper gastrointestinal examination with contrast and endoscopy and computerized tomography scan of the abdomen are considered the most relevant investigations.
Aged↗
Evaluation of an isotope washout technique to measure skin vascular resistance and skin perfusion pressure: influence of age, site and arterial surgery.
A simplified isotope washout technique has been devised to calculate the skin perfusion pressure (SPP) and skin vascular resistance (SVR). This test is simple, requires inexpensive equipment and is well tolerated by patients. SPP and SVR were calculated in 20 patients less than 30 years of age, 13 patients greater than 30 years of age and in 15 patients with peripheral vascular disease (PVD). With increasing age the SPP and SVR were increased. The SPP was similar to the mean arterial pressure in normal individuals but was decreased in patients with PVD. The SPP is a useful indicator of the severity of the PVD. The SPP and SVR were higher in the calf than in the foot. This is probably related to the decrease in pressure in the distal arterial tree. SPP was increased by 110% and skin blood flow by 190% by arterial reconstructive surgery. This test may be of use in assessing the effectiveness of arterial surgery.
Adolescent↗
Skin vascular resistance and skin perfusion pressure as predictors of healing of ischemic lesion of the lower limb: influences of diabetes mellitus, hypertension, and age.
An isotope washout technique that requires inexpensive equipment and is well tolerated by patients has been developed to measure skin perfusion pressure (SPP) and skin vascular resistance (SVR). The SPP is a measure of the severity of peripheral vascular disease and the SVR is an indicator of microangiopathy associated with diabetes mellitus and hypertension. This test has been applied to 87 patients who had ischemic lesions of the lower limb. Fourty-four patients had lesions that healed with local treatment while the other 43 required major surgery. The presence of diabetes, hypertension, and old age reduced the likelihood of healing. Similarly if the SPP less than 40 mm Hg, only 18% of patients' lesions healed. If the SPP lay between 40 and 50 mm Hg and the SVR less than 1000 U, 67% of lesions healed. However, if the SPP was between 40 and 50 mm Hg and the SVR greater than 1000 U, no lesions healed. If the SPP greater than 50 mm Hg and SVR less than 1000 U, 83% of lesions healed, where as if the SVR greater than 1000 U, healing occurred in only 23% of lesions. This test can be used to predict the likelihood of healing of ischemic lesions of the lower leg, thus rationalizing their management. The importance of microangiopathy is also demonstrated.
Adult↗
Martorell's hypertensive ischemic leg ulcers are secondary to an increase in the local vascular resistance.
In 1945 Martorell described ischemic leg ulcers in patients with hypertension and suggested that the ischemic necrosis was secondary to hypertensive arteriolar disease. The aim of the study was to examine the minimum vascular resistance in the skin of patients with these ulcers. Twelve control subjects (median age 52 years), eight patients with peripheral vascular disease (PVD) (median age 73 years), and six patients with hypertensive ulcers (median age 74 years) were studied. The minimum vascular resistance (MVR) and skin perfusion pressure (SPP) were determined by an isotope clearance method. Presence and severity of PVD were assessed by ankle/arm pressure ratios. The ulcer patients had a higher ankle/arm pressure ratio than the PVD group (p = 0.026) but had similar SPP (p = 0.47). When compared with the control group they had a similar pressure ratio (p = 0.09) but lower SPP (p = 0.001). The MVR was higher in the ulcer patients than the control subjects (p = 0.005) and the PVD group (p = 0.01). The study shows that patients with hypertensive ulcers have a high vascular resistance. This increase in resistance may interfere with the compensatory relaxation that normally occurs distal to an arterial narrowing, resulting in poor tissue perfusion and subsequent ulcer development.
Adult↗
Calcified pancreatic pseudocyst--a report of two cases.
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Calcinosis↗
The effectiveness of local injections of vasodilating agents to produce vasodilation in subcutaneous tissue in rabbits.
The isotope washout method has been widely used to study characteristics of the microcirculation in localized vascular beds. Some of these studies have used local injections of vasodilating agents to maximally dilate the vascular bed. This study was undertaken to determine the agent most effective in producing this critical vasodilation. A rabbit model was constructed that allowed the study of the subcutaneous blood flow by either 133Xe and 131I-antipyrine washout. Dose-response curves were constructed for five agents. The agents used and the doses that produced the maximum washout rate, were histamine (100 micrograms), verapamil (0.5 mg), prostaglandin E1 (6 micrograms), papaverine (5 mg) and nitroprusside (60 micrograms). The five agents at these doses were compared with each other, and nitroprusside produced a greater washout rate than papaverine (P less than 0.005), histamine (P less than 0.001) and verapamil (P less than 0.005). There was no difference between nitroprusside and prostaglandin E1 (P greater than 0.01). The effect of three of the agents in producing tissue oedema was examined by comparing the washout rates values obtained with the two isotopes. Both nitroprusside and papaverine produced large oedema whereas histamine resulted in little oedema formation. Nitroprusside, therefore, appears to be the most suitable vasodilating agent for use in studies which require maximum vasodilation of localized vascular beds.
Alprostadil↗
Effects of acute changes in blood volume on the carotid sinus baroreceptor reflex in conscious rabbits.
The control of blood pressure, heart rate, cardiac output and systemic vascular resistance by the carotid sinus baroreceptor reflex was studied in six conscious rabbits during states of acute hypervolaemia and acute hypovolaemia. These states were produced by infusing blood equal to 20% and 40%, and withdrawing blood equal to 20% and 35%, of the initial blood volume. The properties of the reflex were characterized by creating sinusoidal pressure changes across the wall of the carotid sinus at a frequency of 0.01 Hz and amplitudes of 54 and 83 mmHg. From the effects of the lower-amplitude stimulus the dynamic gain of the reflex was calculated for blood pressure, heart rate, cardiac output and systemic vascular resistance. The higher-amplitude stimulus was used to determine the near maximal responses of the circulatory variables to changes in carotid sinus transmural pressure. The gain for systemic vascular resistance was reduced by hypervolaemia, and increased by 20% hypovolaemia. The gains for heart rate and blood pressure were not affected by hypervolaemia or by 20% hypovolaemia. 35% hypovolaemia reduced the gain for heart rate, but the resting value was close to the upper limit of the reflex response. It also reduced the gain for cardiac output and blood pressure, and the increase in gain for systemic vascular resistance that had been caused by 20% hypovolaemia was not sustained.
Animals↗