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Biomedical subjects

P Ohlin

Publications and source records attributed to P Ohlin.

At least 19 recordsLinked to original sources
PubMed1992

Ventilation of the paranasal sinuses studied with dynamic emission computer tomography.

This investigation's aim was to study a noninvasive method for determining the ventilation of the nasal sinuses. For this purpose, different insufflation techniques using xenon 133 were tried, along with different scintillation camera techniques. Xenon 133 gas was used for insufflation in the nose and sinuses, and the half-time of the washout curves was determined with the aid of digital scintillation cameras, one of which was capable of dynamic tomography. The tomographic procedure was superior because it made it possible to study the washout from the ethmoidal/sphenoidal sinuses as well. The washout was followed for up to 150 minutes. Great variations in washout were found between different sinuses and also in the same sinus over time. The single photon emission computed tomography (SPECT) technique, which is easy to perform and gives a limited absorbed dose to the patient, seems promising for the future evaluation of sinus ventilation and ostial function.

Absorption↗
PubMed1992

Does nicotine administration influence intragastric acidity?

Smokers have an increased incidence of duodenal ulcer with a high relapse rate whether they receive maintenance therapy with H2-receptor antagonists or not. They also tend to be slow healers. The etiology behind this is still unknown, and there is general disagreement as to whether smoking affects gastric secretion. In an earlier study we found a small but significant decrease in intragastric pH a short time after smoking a cigarette. The aim of the present investigation was to study whether intragastric pH changed during nicotine administration per se. Nicotine was given as a nasal spray to eight healthy smokers. Nicotine did not induce any acute detectable changes in gastric acidity when the 5-min period before spraying was compared with the 35-min period after spraying (median pH, 1.47 (25-75 percentiles, 1.40-2.32) and 1.55 (25-75 percentiles, 1.42-2.06), respectively). When different time periods during a day with hourly nicotine administration were analyzed, and the results compared with those of a similar day when placebo was given, nicotine was found to impair postprandial gastric neutralization. Median pH during the lunch hour was 1.93 (25-75 percentiles, 1.80-2.37) after nicotine and 2.86 (25-75 percentiles, 2.37-3.70) after placebo; p less than 0.025. Possible explanations for this might be nicotine-mediated effects on gastric motility or gastrin release.

Adult↗
PubMed1990

Venous function assessed during a 5 year period after acute ilio-femoral venous thrombosis treated with anticoagulation.

To determine the chronological changes of venous physiology following major thromboses, 20 patients were repeatedly examined for over 5 years after an acute ilio-femoral thrombosis which was treated with conventional anticoagulation. Radionuclide angiography showed that 70% of the patients had obstructive lesions of the iliac vein with only minor changes occurring from 6 months to 5 years. In spite of this, the plethysmographic maximum venous outflow increased from 31 to 45 ml/min/100 ml (P less than 0.001). The foot volumetric reflux did not change with time and about half of the patients had abnormal values. Venous reflux assessed by the refill time of foot vein pressure, deteriorated with time (P less than 0.05), and at 5 years all but one patient had a refill time less than 20 s. The muscle pump function, examined by foot volumetry, was abnormally low in about half of the patients throughout the study. The ambulatory foot vein pressure was constantly pathological (greater than 60 mmHg) in half of the patients and only two of 18 patients had normal values (less than 45 mmHg) at 5 years. Five patients with thromboses involving only the proximal veins had better physiological results than 15 patients with thromboses that extended to the peripheral veins. Three patients who developed venous claudication had iliac vein obstruction and an impaired venous outflow and three patients who developed venous ulcers had venous reflux and severe venous hypertension. Although venous outflow continuously improves following ilio-femoral thromboses, valvular competence and muscle pump function are constantly pathological, creating severe venous hypertension with a risk of post-thrombotic sequelae.

Anticoagulants↗
PubMed1990

Long-term results of venous thrombectomy combined with a temporary arterio-venous fistula.

Forty-one patients with acute iliofemoral venous thrombosis were randomised to conventional anticoagulation or acute thrombectomy combined with a temporary arterio-venous fistula (AVF) and anti-coagulation. Follow-up after 5 years in 22 medical and 19 surgical patients revealed slightly more asymptomatic patients (37 vs. 18%) and less frequent severe post-thrombotic sequelae (16 vs. 27%) in the surgical group (N.S.). The iliac vein was more frequently (P less than 0.05) normal following thrombectomy (71 vs. 30%) as demonstrated by radionuclide angiography, but occlusion plethysmography showed an outflow capacity (61 vs. 45 ml/min/100 ml) that was not significantly better. There was no obvious difference in muscle pump function (EVrel) and reflux (Q/EVrel) assessed by foot volumetry. Still, the ambulatory venous pressure was significantly (P less than 0.05) lower in the surgical group. There was a tendency towards better results following thrombectomy in patients with fresh thrombosis and a successful initial procedure. Although the numbers of observations in many cases were too small to provide statistical evidence of benefit with venous thrombectomy + AVF, this procedure seems to improve the long-term outcome following acute iliofemoral venous thrombosis. Since the difference in outcome is not very striking, anticoagulation treatment is still an acceptable alternative.

Acute Disease↗
PubMed1989

A modified method of curve analysis in foot volumetry and its reference values.

Foot volumetry was introduced by Norgren & Thulesius in 1973 as a non-invasive method of functional evaluation of venous insufficiency. In the following paper we suggest a slightly different method of curve analysis, thus showing the possibility of reducing the methodological error by 30-40%. Based on healthy men and women between 15 and 75 years, new reference values are presented.

Adolescent↗
PubMed1988

Non-invasive recognition of arrhythmogenic right ventricular dysplasia.

Arrhythmogenic right ventricular dysplasia causes ventricular arrhythmias and sometimes heart failure. The condition is easily overlooked, but once suspected, it may be diagnosed non-invasively. This is illustrated by the case reported. The clinical features of this syndrome are discussed, with special emphasis on the non-invasive findings.

Adult↗
PubMed1988

Diagnosis of deep vein thrombosis with a new radionuclide method--99Tcm-albumin test.

The diagnostic efficiency of 99Tcm-albumin test (AT), a new radionuclide method, was evaluated in 90 consecutive patients with suspected deep vein thrombosis (DVT) admitted to the medical emergency ward. Phlebography was used as reference method. The sensitivity of the AT test was 92% and the specificity was 61%. As the method is objective, rapid and convenient for the patients, it can be recommended as an initial examination method to be followed by phlebography, in cases with a positive test result. Criteria with high specificity, 98%, have also been defined but these criteria should be further investigated.

Adult↗
PubMed1988

[Fixation of fractures of the femoral neck using screws or hook-pins. Radionuclide study and short-term results].

In a prospective randomized investigation, AO screws (53 cases) and hook-pins (57 cases) were used for femoral neck fracture fixation in 110 cases. The results of the one-week postoperative scintimetry and a four-month radiographic follow-up were analysed. The femoral head vitality according to scintimetry was similar in the two groups, whether undisplaced or displaced fractures. Within four months from the operation, six cases with screw fixation had been subjected to total hip arthroplasty while only one with hook-pins, all because of fracture redisplacement. However, at the four-month control, another more fracture operated on with screws and five more operated on with hook-pins were scheduled for hip arthroplasty. Thus, no difference between the two methods regarding postoperative femoral head vitality or complications in short term follow-up, was noted.

Adult↗
PubMed1987

Ketanserin in intermittent claudication: effect on walking distance, blood pressure, and cardiovascular complications.

In a 7-center Scandinavian double-blind placebo-controlled study of 179 patients with intermittent claudication, the effect of the serotonin antagonist ketanserin was evaluated on walking distance, brachial and ankle blood pressure, and symptoms. For all centers together, pain-free walking distance was significantly increased after 6 months with both ketanserin (+65%; 71 patients) and placebo (+42%; 78 patients), with no significant difference. However, there was large variability among centers. Classification of "responders" (doubling of walking distance) and patients who deteriorated (decrease of walking distance or dropout for inefficacy) showed significantly more patients responding and significantly fewer patients deteriorating with ketanserin than with placebo. Systemic blood pressure was significantly decreased by ketanserin in hypertensive, but not normotensive, patients, while ankle pressure was unaffected. The incidence and nature of side effects were equal with ketanserin and placebo, but there were more side effects causing dropout in the ketanserin group. An unexpected and possibly important observation was the occurrence of six serious cardiovascular events (myocardial infarction, cerebrovascular complications, and development of rest pain) in the placebo group but none in ketanserin-treated patients. Moreover, there were four additional similar complications in the placebo run-in period. Ketanserin appears to be beneficial in a subgroup of patients with intermittent claudication. A fortuitous finding of this study is that ketanserin might possess a protective effect against thrombovascular complications in patients with intermittent claudication.

Adult↗
PubMed1986

Return to normal of 99mTc-plasmin test after deep venous thrombosis and its relationship to vessel wall fibrinolysis.

Fourteen patients with deep venous thrombosis (DVT) and a positive 99mTc-plasmin test were followed up to determine how soon a negative test was obtained. Localization and extension of the thrombi were determined by phlebography. Plasminogen activator activity in vein walls and local fibrinolytic activity after venous occlusion were measured in order to find out what the prerequisites for impaired thrombolysis are. The time required to obtain a negative 99mTc-plasmin test showed considerable variation, ranging from less than 1 week to more than 6 months. The 99mTc-plasmin test had returned to normal in 64% of the patients after 6 months. No relationship was found between vessel wall fibrinolysis and time to normalization. Instead, we found an association between the time to normalization of the 99mTc-plasmin test and the size of the thrombus, according to phlebography, as well as between the time to normalization of the 99mTc-plasmin test and the extension of leg points with a positive 99mTc-plasmin test at admission. The finding of abnormal 99mTc-plasmin test results more than 6 months after acute DVT is of practical importance and warrants caution when evaluating patients with symptoms and signs suggestive of acute recurrent DVT.

Adult↗
PubMed1986

Follow-up of circulatory changes secondary to deep venous thrombosis with special regards to radionuclide tests.

The influence of circulatory changes, which are secondary to deep venous thrombosis (DVT) in the leg, on result of radionuclide tests was studied in eight patients. Strain gauge plethysmography, a radionuclide blood-pool test and phlebography were performed both in the acute phase and during recovery up to 6 months after the initial admission. Morphological and functional changes were correlated with results from repeatedly performed 99Tcm-plasmin tests, a test currently used for diagnosis of DVT. In the acute phase, the thrombotic leg showed an increase in pooled blood and, in the case of proximal thrombosis, also impaired venous outflow. During the 6-month follow-up complete recanalization was observed in three patients and partial recanalization in five. The circulatory changes were found to recover progressively and earlier than the morphological changes. The 99Tcm-plasmin test was pathological at admission in all patients. It was normalized in parallel with plethysmography and blood-pool test results, at a time when morphological recovery was still incomplete. These findings confirm that a positive 99Tcm-plasmin test reflects haemodynamic changes which are secondary to the DVT rather than a specific binding of the radiopharmaceutical to the thrombus. The 99Tcm-plasmin test was normalized from 1 to more than 26 weeks after an acute DVT. This finding is of practical importance when using radionuclide tests for evaluation of acute recurrent DVT.

Aged↗
PubMed1985

Pulmonary embolism in acute iliofemoral venous thrombosis.

Serial perfusion lung scanning and chest radiography were used to study the incidence of pulmonary embolism in patients with acute iliofemoral venous thrombosis. The efficacy of conventional anticoagulation and surgical thrombectomy in controlling embolism and the risk of creating emboli during thrombectomy were also evaluated. Lung scans obtained on admission in 49 patients were normal in 37 per cent, inconclusive in 18 per cent and positive for embolism in 45 per cent of the patients. Symptoms suggestive of embolism were present in only 24 per cent of the patients and correlated poorly with lung scans. Massive embolism was present in only two patients. Additional, usually asymptomatic, emboli developed within one month in 21 per cent of 29 patients treated conservatively with anticoagulation alone and in 20 per cent of 20 patients having acute thrombectomy combined with a temporary arteriovenous fistula and systemic anticoagulation. Only one conservatively treated patient required caval interruption. Pulmonary embolism, usually of minor degree, is thus present in nearly every other patient with acute iliofemoral venous thrombosis. Anticoagulation alone or in conjunction with thrombectomy and arteriovenous fistula in most cases effectively prevents further embolization and the risk of creating additional emboli by the surgical procedure is insignificant.

Adolescent↗
PubMed1985

Does a computer-based ECG-recorder interpret electrocardiograms more efficiently than physicians?

The quality of ECG-interpretations by a computer-based ECG-recorder has been compared with those carried out visually by physicians in routine clinical practice. Independent reports have been analysed on 474 routine ECGs taken in the medical emergency and out-patient departments, as well as in general practice. Computer reports were available for all of the ECGs, but the physicians had not annotated their interpretations in 11% of them. Eighty-two per cent of the computer-interpretations were adjudged as being satisfactory. The corresponding figure for the physicians' interpretations was 64%. The computer-based ECG-recorder was found to be better than the physician at interpreting ECGs.

Diagnosis, Computer-Assisted↗
PubMed1985

Pressures recorded in ulnar neuropathy.

The pressure between the ulnar nerve and the arcade bridging the two heads of the flexor carpi ulnaris muscle was recorded peroperatively in ten patients with electrophysiologically confirmed ulnar neuropathy at the elbow. At rest, with the elbow extended, pressures ranged from 0 to 19 mm Hg but increased in flexion and during isometric contraction of the flexor carpi ulnaris muscle to maximal values above 200 mm Hg.

Adult↗
PubMed1985

Deep venous thrombosis, pulmonary embolism and acute surgery in thrombophlebitis of the long saphenous vein.

Twenty-eight consecutive cases of acute superficial thrombophlebitis of the long saphenous vein above the knee were reviewed concerning presence of asymptomatic deep venous thrombosis and pulmonary embolism and early clinical results after surgical treatment. Contrast phlebography of the ipsilateral leg revealed asymptomatic involvement of major deep veins of the thigh or calf in 4 of 21 examined patients. Perfusion lung scanning and chest radiography demonstrated typical segmental perfusion defects consistent with pulmonary embolism in two of ten examined patients. High ligation and stripping of the phlebitic veins gave prompt cure in 19 patients, though in two who were simultaneously treated with anticoagulants there was troublesome bleeding. Simple high ligation was performed in nine patients without complications, but four of them had protracted phlebitic pain. The results indicated that preoperative phlebography and lung scanning are helpful in detecting associated asymptomatic disorders and for planning therapy in patients with clinically isolated, superficial thrombophlebitis of the long saphenous vein. The treatment of choice is acute high ligation with removal of all phlebitic veins. If anticoagulation is indicated because of concomitant deep venous thrombosis or pulmonary embolism, the initial procedure should preferably be limited to high ligation.

Adult↗
PubMed1985

Iliac vein obstruction associated with acute iliofemoral venous thrombosis. Results of early reconstruction using polytetrafluoroethylene grafts.

The results of iliac vein reconstruction performed early after secondary iliofemoral venous thrombosis were retrospectively evaluated. The review comprised seven patients who underwent acute thrombectomy combined with cross-femoral (4 cases) or iliocaval (3 cases) bypass procedures using polytetrafluoroethylene (PTFE) grafts. The clinical course, graft patency and venous physiology were studied. Five patients had a satisfactory clinical course, but one patient died of postoperative complications and another underwent leg amputation after 20 months. Contrast and radionuclide phlebograms showed that only two grafts were still patent after two years, but only one of these was still patent five years postoperatively. Clinical symptoms and physiologic parameters correlated poorly with graft patency, demonstrating the necessity of phlebography in evaluating patency rates after venous surgery. Our study indicates that early venous reconstruction using PTFE grafts does not result in satisfactory long-term patency rates. Further development of graft materials suitable for the venous system is required.

Acute Disease↗