Endoscopic removal of a dental instrument from the stomach: case report

The records of 628 patients admitted to the Joint Study of Extracranial Arterial Occlusion with transient symptoms of carotid system ischemic disease were examined to determine the accuracy of predicting disease of the extracranial internal carotid artery on the basis of clinical information alone. A patient with a history of episodes of amaurosis fugax is more likely to have a lesion of the internal carotid artery on the same side than if he were having only transient cerebral ischemic attacks. In patients with transient symptoms and a carotid bruit on the appropriate side, the incidence of an angiographically normal carotid artery was 15%. In those patients with transient symptoms and no palpable pulsation in the cervical region on the appropirate side, the incidence of an angiographically normal carotid artery was zero.     

Radiation exposure of the population by roentgen diagnosis. II. The collective effective dosage of the population in former East Germany caused by 1987/1988 roentgen diagnosis

OBJECTIVES: To examine the relations between the development of neurologic events and the following variables: degree of stenosis of the contralateral carotid artery, prior neurologic symptoms and stump pressure of the ipsilateral internal carotid artery in patients undergoing carotid endarterectomy under regional anesthesia. PATIENTS AND METHODS: We undertook a prospective study of 92 patients undergoing carotid endarterectomy with a blockade of the superficial and deep cervical plexus. Neurological integrity was assessed and internal carotid artery stump pressure was monitored. Contralateral carotid artery stenosis and neurologic disease present before surgery were studied. RESULTS: Neurologic events developed when the carotid artery was clamped in 9.7% of patients. Mean stump pressure was significantly lower in symptomatic patients (43 +/- 11 mmHg) than in asymptomatic patients (74.6 +/- 24 mmHg) (p < 0.001). Neurologic symptoms developed during clamping of the carotid in 27.2% of the patients with stump pressure less than or equal to 50 mmHg, but in only 4.2% of those with stump pressure surpassing 50 mmHg. Stump pressure was significantly lower in patients with contralateral carotid stenosis. The incidence of neurologic events during clamping was unrelated to contralateral carotid condition, however. Likewise, neurologic symptoms before surgery was also unrelated. In six of the nine patients with neurologic events, internal carotid stump pressure was less than or equal to 50 mmHg, indicating that the sensitivity of this parameter to the development of neurologic events in our series was 66%. CONCLUSIONS: Although internal carotid artery stump pressure identifies a subset of patients likely to have a higher incidence of neurologic events during carotid artery clamping, it can not be considered the only criterion for placement of an intraluminal shunt to prevent such events. The state of the contralateral carotid artery and preexisting neurologic symptoms are not objective screening criteria for identifying patients at high risk of neurologic events during carotid clamping.     

Noninvasive assessment of collateral blood flow of the cerebral hemisphere by Doppler ultrasound

Directional flow in the frontal artery, a terminal branch of the ophthalmic artery, was assessed nonivasively by Doppler ultrasound druing brief digital compression of the ipsilateral common carotid artery in 62 patients. Directional frontal artery flow during carotid compression was compared with mean distal internal carotid back pressure measured at subsequent carotid endarterectomy. Mean carotid back pressure in 28 patients with normal frontal artery flow direction during carotid compression, 68 +/- 14 millimeters of mercury, was significantly higher than that observed in 24 patients in whom frontal artery flow was completely obliterated and ten in whom frontal artery flow was reversed. Distal internal carotid back pressure exceeded 48 millimeters of mercury in all patients with normal frontal artery flow direction during carotid compression. Conversely, carotid back pressure was below 41 millimeters of mercury in all but one patient in whom frontal artery flow was obliterated or bliterated or reversed during carotid compression. The results of this study indicate that Doppler ultrasound assessment of frontal artery flow direction during simultaneous carotid compression provides a rapid, sale noninvasive estimate of the adequacy of collateral hemispheric circulation.     

Correlation of neurologic complications and pressure measurements during carotid endarterectomy

There was no significant difference between the mean occluded internal carotid artery pressure in asymptomatic, transient ischemic attack or prior stroke patients. The stump pressure was not consistently elevated at the second operation in those having undergone bilateral procedures. Estimate of back bleeding from the internal carotid artery operation did not necessarily correlate with the stump pressure. Adequate back bleeding was recorded in patients with a low stump pressure, and reduced bleeding was noted in individuals with a high stump pressure. The pressure gradient across the stenosis of the bifurcation of the carotid artery was helpful in assessing the degree of stenosis present. The occluded internal carotid artery pressure seemed to be a helpful aid in indicating those patients with poor collateral flow and, therefore, at high risk of ischemic brain damage. The use of an inlying shunt in those individuals having a low stump pressure may be expected to reduce the over-all neurologic complication rate in patients undergoing carotid endarterectomy.     

Carotid stump pressure, stump pulse, and retrograde flow

In order to obtain a more comprehensive intraoperative hemodynamic profile and to predict hypoperfusion during carotid endarterectomy, stump pressure, stump pulse, and retrograde internal carotid flow were measured in 261 patients. Our results show a significant correlation between stump pressure and retrograde flow (p < 0.001), stump pressure and the presence of a stump pulse (p < 0.001), and retrograde flow and the presence of a stump pulse (p < 0.001). We also demonstrated a significant correlation between stump pressure (lower), retrograde flow (less), and the absence of a stump pulse in patients with contralateral carotid artery occlusion. There was no correlation between the indication for carotid endarterectomy and any hemodynamic measurement. The triad of stump pulse, stump pressure, and retrograde flow accurately reflects collateral blood flow when the carotid is cross-clamped. These determinations can be obtained at low cost and are easily and rapidly performed. A protocol for selective shunting in patients undergoing carotid endarterectomy with general anesthesia is suggested.     

The influence of the prolactin inhibitor bromocriptin (CB 154) on human luteal function in vivo

Intra-aneurysmal pressure and piezometric head differences with respect to common carotid values have been recorded by unidirectional and differential transducers in two patients undergoing craniotomy for aneurysms of the anterior communicating and middle cerebral arteries. Recordings were taken under normal systemic arterial pressure during temporary occlusion of the common carotid artery, during intra operative carotid arteriography and under controlled arterial hypotension. Predominance of the common carotid pressure head and piezometric head over the aneurysmal value was found in the two cases.     

Myocardial involvement in systemic lupus erythematosus. A noninvasive study of left ventricular function

A relatively high incidence of heart failure is noted among patients with systemic lupus erythematosus (SLE) without clearly defined clinical causes. To evaluate left ventricular performance in patients with SLE without evidence of cardiovascular disease, noninvasive measurement of the systolic time intervals was carried out. Simultaneous recording of the electrocardiogram, phonocardiogram and carotid arterial pulsation were obtained in 25 patients with systemic lupus erythematosus and compared with 22 normal subjects. The patients with SLE had a shorter left ventricular ejection time (P less than 0.05), a longer pre-ejection period (P less than 0.02) and an increased ratio of pre-ejection period/left ventricular ejection time (P less than 0.005). These abnormalities on ventricular function were independent of age, duration of the disease, hypertension, renal involvement, anemia, immunologic activity and corticosteroid treatment. Several etiologic possibilities are discussed and the clinical usefulness of this method to detect and follow-up the cardiac dysfunction in systemic lupus erythematosus is emphasized.     

Cerebrospinal fluid pressure changes in response to coughing

CSF pressure recordings have been taken from the lumbar region and the cisterna magna of 16 patients during coughing in the sitting position. Isolated coughs of low amplitude have been studied. The lumbar pressure waves occur sooner and lower. Thus there is a phase during which the lumbar pressure exceeds the cisternal, followed by one in which the cisternal exceeds the lumbar. These phenomena may be conveniently displayed on a differential trace. The phase during which the cisternal pressure exceeds the lumbar may be protracted. It is suggested that Froin's syndrome, central subarachnoid pouches and syringobulbia may be associated with upward pressure waves. Cough headache, the filling stages of communicating syringomyelia and tonsillar herniation may be associated with valve-like blockage at the foramen magnum which produces craniospinal pressure dissociation by interfering with downward or rebound pulsation. Decompensation of hydrocephalus after birth may be related to pulsation in association with crying; also after removal of a meningocele sac decompensation may be related to the effects of similar pulsation modified by changes in capacitance following operation. The cord destruction of syringomyelia, and the mechanisms which fill spinal subarachnoid cysts may be related to pressure waves directed both upwards and downwards. The merits and limitations of cough impulse as a clinical test for spinal blockage are discussed, and the suggestion is made that after further evaluation they may provide a more sensitive indication of spinal blockage than Queckenstedt's test.     

Effects of immunotherapy on experimental immunodeficiency-related lymphoproliferative disease

BACKGROUND: In patients affected by carotid sinus hypersensitivity, long-term vasodilator therapy might increase the risk of syncopal episodes by reducing systolic blood pressure and venous return to the heart. METHODS AND RESULTS: Thirty-two patients (mean age 73 +/- 9 years; 20 men) who met all the following criteria were included: (1) one or more episodes of syncope occurring during long-term (>6 months) treatment with angiotensin-converting enzyme inhibitors, long-acting nitrates, calcium antagonists, or a combination of these; (2) a positive response to carotid sinus massage, defined as the reproduction of spontaneous syncope in the presence of ventricular asystole > or =3 seconds or a fall in systolic blood pressure > or =50 mm Hg; (3) negative workup for other causes of syncope. The patients were randomly assigned to continue or to discontinue use of vasodilators; carotid sinus massage was repeated 2 weeks after randomization. By the end of the study period, the baseline values of systolic blood pressure were significantly different between the 2 groups of patients both in supine (P=.01) and upright (P=.03) positions. Syncope had been induced by carotid sinus massage in 81% of patients in the "on-vasodilator" group and in 62% of patients in the "off-vasodilator" group (P=.21). The cardioinhibitory reflex was of similar magnitude in the 2 groups, being found in 50% of the patients in each group, with a maximum ventricular pause of 7.1 +/- 2.7 and 6.7 +/- 1.8 seconds, respectively. The percentage decrease of blood pressure did not differ between the 2 groups, even if, in absolute values, the baseline difference of blood pressure roughly persisted for the duration of the test. In consequence of that, the rise of blood pressure to similar values was delayed approximately 30 seconds in the "on-vasodilator" group and took more than 2 minutes to return to baseline values. CONCLUSIONS: In patients affected by carotid sinus hypersensitivity, chronic vasodilator therapy does not have a direct effect on carotid sinus reflexivity, although the delayed recovery of pretest blood pressure values could indirectly potentiate the severity of the clinical manifestations of the syndrome. The persistence of hypotension for a longer time after the end of the massage suggests that vasodilators cause an impairment of compensatory mechanisms.     

Role of transcranial Doppler and stump pressure during carotid endarterectomy

BACKGROUND AND PURPOSE: The aim of our study was to clarify the pathophysiology of perioperative cerebral complications during carotid endarterectomy in our series. METHODS: By means of transcranial Doppler ultrasonography and stump pressure measurement, we monitored 112 patients who underwent carotid endarterectomy under general anesthesia for symptomatic or asymptomatic severe carotid stenosis. RESULTS: Of 18 patients who underwent carotid endarterectomy with intra-arterial shunt, 2 (11.1%) developed an ischemic stroke. Of the other 94 patients, one suffered a nucleocapsular hemorrhage and 5 had cerebral ischemic complications. In these 5 patients, the duration of clamping was significantly longer (mean +/- SD, 16.4 +/- 1.1 versus 12.7 +/- 2.6 minutes; P = .0019), and the decrease of middle cerebral artery mean velocity on clamping was significantly greater (mean +/- SD, 56.4 +/- 4.9% versus 28.8 +/- 20.2%; P = .0031), while stump pressure was not significantly different. Microembolic signals were recorded in 70 patients (62.5%) and were not associated with cerebral ischemic complications. The 7 patients who developed cerebral ischemic complications had a significantly higher percentage of stenosis in the contralateral internal carotid artery (mean +/- SD, 82.0 +/- 17.8% versus 29.3 +/- 36.4%; P = .0018). CONCLUSIONS: The results of our study suggest that the major complications of carotid endarterectomy may be due to hemodynamic factors. Stump pressure alone is not a reliable indicator of hemodynamic changes that predict cerebral ischemia. Particulate microembolism may cause more subtle changes in cerebral parenchyma, but further studies are needed to clarify this point.     

Geographic distribution of leukemia mortality in young people aged 0-24 years in France

Patients with significant stenosis at the carotid bifurcation are traditionally subjected to four vessel aortic arch angiography prior to consideration for carotid endarterectomy. The advent of the non-invasive vascular laboratory has necessitated a reappraisal of this approach. AIMS: 1. Determine the yield from aortic arch angiography and its influence on surgical management. 2. Evaluate the accuracy of clinical examination and the non-invasive vascular laboratory in the detection of aortic arch branch lesions. METHODS: One hundred and twenty-nine consecutive patients undergoing evaluation for carotid endarterectomy were prospectively enrolled into the study. The protocol entailed: 1. Clinical recording of upper limb pulses, blood pressure and supraclavicular bruits. 2. Duplex scan examination to evaluate proximal inflow into the carotid arteries. 3. Four vessel aortic arch angiography to detect aortic branch lesions. Data from the non-invasive tests were compared to angiography. Patients with aortic arch branch lesions were further evaluated to determine the proportion requiring additional surgery. RESULTS: Nineteen patients had angiographic evidence of aortic branch disease (14.7%); six involved the common carotid artery, three the innominate artery and 10 the subclavian artery. All of these lesions were detected by the combination of unequal blood pressure, pulse deficit, bruit or duplex scan. Seven patients underwent additional surgery (5.4%) which included carotid-subclavian bypass (five), aortoinnominate bypass (one) and innominate endarterectomy (one). CONCLUSION: In patients with significant stenosis at the carotid bifurcation undergoing evaluation for carotid endarterectomy, aortic arch angiography is unnecessary except in a small percentage of patients with abnormal clinical and non-invasive findings.     

Safety of carotid ligation and its role in the management of intracranial aneurysms

By using measurements of cerebral blood flow and internal carotid artery pressure it is possible to select patients in whom carotid ligation can be performed with a very low risk of post-operative cerebral ischaemia. A study has been carried out in 100 patients comparing this method with clinical predictions of the type used in aneurysm surgery based on age of the patient, arterial hypertension, time from latest subarachnoid haemorrhage, and neurological status on a modified Botterell scale. These clinical factors were found to be of little value in predicting which patients would and would not develop cerebral ischaemia after carotid occlusion.     

Impaired dynamic cerebral autoregulation in carotid artery stenosis

BACKGROUND AND PURPOSE: If it could be determined whether cerebral blood flow can be maintained (autoregulated) during transient falls in arterial blood pressure, we might be able to identify patients with carotid stenosis who are at risk of stroke. However, conventional methods of determining autoregulation in such patients are invasive and/or expensive. METHODS: We used a new noninvasive method to estimate dynamic cerebral autoregulation in 27 patients with carotid stenosis and 21 age-matched normal controls. After a stepwise fall in arterial blood pressure, we determined the rate of rise of middle cerebral artery blood flow velocity compared with that of arterial blood pressure. We compared the method with a conventional method of determining cerebral hemodynamics, CO2 reactivity. RESULTS: Autoregulatory index (ARI) was significantly reduced in middle cerebral arteries ipsilateral to a stenosed/ occluded carotid artery: mean +/- SD 3.3 +/- 2.2 compared with normal controls (6.3 +/- 1.1; P < .0001) and nonstenosed carotid arteries in patients (5.9 +/- 2.1; P < .002). A subgroup of patients with severe impairment was identified. ARI returned to normal after carotid endarterectomy was performed. In a number of cases, ARI was impaired in the presence of CO2 reactivity. CONCLUSIONS: This simple technique allows identification of impaired autoregulation in patients with carotid artery disease. It may allow identification of patients at risk from transient falls of blood pressure as may occur at the onset of antihypertensive therapy and during surgery. It may allow a subgroup of patients with asymptomatic carotid stenosis who are at risk of hemodynamic stroke to be identified.     

Relationship between mechanical properties of the carotid artery wall and baroreflex function in acutely treated hypertensive patients

OBJECTIVE: To evaluate the relationship between the mechanical properties of the carotid artery wall and baroreflex function after acute reduction of blood pressure with lacidipine in essential hypertension. DESIGN: After 15 days of placebo washout, the hypertensive patients underwent a single-blind haemodynamic study before and 90 min after administration of 4 mg lacidipine (a dihydropyridine calcium antagonist). METHODS: Brachial intra-arterial blood pressure was recorded in eight mild-to-moderate essential hypertensive patients aged 40-53 years (mean +/- SEM 46.8 +/- 4.7 years). The carotid pulse diameter was recorded simultaneously by an echo-tracking technique. The mechanical properties of the carotid artery wall were evaluated by calculating Peterson's incremental elastic modulus (Ep) both as an averaged value of 10 heart cycles with stable blood pressure and was the dynamic correlation, on a beat-to-beat basis, of Ep and the systolic blood pressure during a 20 mmHg increase in blood pressure following a bolus injection of phenylephrine. The elastic properties of the carotid artery were investigated further by determining the correlation between the systolic pressure and systolic diameter, beat by beat, during a ramped increase of blood pressure after phenylephrine administration. The baroreceptor reflex sensitivity was measured simultaneously by the Oxford method and by correlating Ep and the electrocardiographic R-R' interval on a beat-to-beat basis during phenylephrine injections. RESULTS: After lacidipine administration Peterson's elastic modulus, measured under resting steady-state conditions, was reduced (18.7 +/- 7.4 versus 16.4 +/- 6 x 10(5) dyne/cm2), whereas the baroreflex sensitivity was unchanged (6.6 +/- 3.3 versus 6.3 +/- 0.2 ms/mmHg) and resetting of the baroreflex had occurred. At the same time, the correlations between the systolic blood pressure and Ep and between the systolic blood pressure and carotid systolic diameter over a 20 mmHg increase in blood pressure were unchanged. Moreover, the correlations between the systolic blood pressure and the R-R' interval and between Ep and R-R' interval during the phenylephrine-induced blood pressure increase did not differ statistically. CONCLUSIONS: The results suggest that the resetting of the baroreflex after the acute reduction in blood pressure caused by lacidipine is dissociated from mechanical changes in the carotid artery wall.     

Spontaneous pulsation of the retinal veins

The classical theory of spontaneous pulsation of the retinal veins is that during systole intraocular pressure exceeds venous pressure, causing the veins to collapse. We show that this theory is internally inconsistent and not in accord with experimental data. It is inconsistent in assuming both (a) that oscillations of intraocular pressure (IOP) occur because the veins cannot immediately discharge the systolic arterial inflow and (b) that retinal venous pressure (RVP) can fluctuate independently of IOP during the cardiac cycle. It is not in accord with experimental data, which shows that RVP always exceeds IOP and that fluctuations in the latter are instantly transmitted to the former. We present an alternative theory that does not have these problems. We assume the following. (1) Inflow to the retinal venous tree from the capillaries is constant, the pulsatile arterial flow having been completely damped by the arterioles and capillaries. (2) Outflow from the central retinal vein (CRV) varies during the cardiac cycle because oscillations of IOP, transmitted to the intraocular CRV, are of greater amplitude than oscillations in cerebrospinal fluid pressure, transmitted to the extraocular CRV. By showing that the radial blood flow distending the veins obeys a diffusion equation and by employing an "equivalent cylinder" analysis of the branched venous tree to simplify the boundary conditions, we demonstrate that, with the above assumptions and the additional assumption of low amplitude of radial flow, the CRV will pulsate, and the pulsations will remain confined to a small segment near the exit point. The proposed theory can explain disappearance of pulsation with intracranial hypertension, intensification of pulsation in glaucoma, and variability in the linear extent and amplitude of pulsation among normal individuals. The theory may also be applied to other venous pulsations, such as the respiratory pulsation of the terminal portions of large veins entering the thorax or the cardiac cycle pulsation of the superior vena cava.     

Stump pressure: an unreliable guide for shunting during carotid endarterectomy

A correlative analysis was made between the neurological status of the awake patient and the internal carotid artery stump pressure in 125 consecutive patients undergoing carotid endarterectomy. There was no mortality in this series. Twenty-four patients lost consciousness immediately after carotid cross-clamping, even though stump pressures were above 50 mm Hg in more than one third of the cases. The majority (80.8%) of the patients tolerated cross-clamping (stump pressures were between 20 and 90 mm Hg). This study demonstrated the variability of cerebral tolerance relative to absolute stump pressure guidelines, such as 25 or 50 mm Hg; reliance on these values to determine the need for intraoperative shunting could lead to stroke at operation. Our experience also showed that assessment of the awake but tranquil patient continues to be the safest and most reliable guide to selective shunting during carotid endarterectomy.     

Influence of carotid atheroma on the neurologic status after myocardial revascularization

Surgical management of the carotid disease remains controversial in patients affected with coronary artery atheromatous disease. We report the Montreal Heart Institute experience on the influence of carotid disease on postoperative neurologic events of 501 consecutive patients operated on for coronary revascularization during the period from January 1994 to December 1994. There were 381 men and 114 women averaging 62 +/- 9 years old. Major risk factors were high blood pressure (35%), and smoking habit (48%). Fifty-nine patients presented clinical signs of carotid atheromatosis and among them 21 had significant carotid stenosis (> 80% decrease of cross sectional area). During surgery, the mean duration of extracorporeal circulation (ECC) was 76 +/- 31 minutes and the mean perfusion pressure (MPP) was 70 +/- 11 mmHg. The use of inotropic drugs was mandatory in 26% of the cases and the mean arterial lactate (AL) dosage during ECG was 3.07 +/- 1.35 mM/L. During the perioperative period, 13 (2.5%) patients sustained neurologic disturbances of which 5 (1%) were lateralized. Among them, 8 completely recovered whereas 3 of the 5 with permanent damage died. None of the patients with preoperative stigmata of carotid disease experienced lateralized neurologic deficit. Multivariate regression analysis identified the use of vasopressor drugs and perioperative increase of AL as predictive factors. We conclude that in our series, the incidence of neurologic complications was low. The presence of carotid atheromatosis did not increase the postsurgical risk of cerebrovascular accident, however, the increased incidence of neurologic events associated with inotropic drugs and increased AL suggests a direct link with a systemic oxygen debt. Consequently, we do no recommend concurrent prophylactic surgery during coronary artery revascularization.     

外啮合非对称齿轮泵优势分析

研究了新型非对称双压力角齿轮泵,得出非对称齿轮利用工作侧压力角的增大或齿数的增加能提高流量的同时可有效减小脉动系数的结论.同时工作侧压力角的增大,最小油膜厚度和油膜比厚显著增大,对改善齿面润滑极为有利,并用Matlab软件进行了仿真验证,为进一步推广非对称齿轮泵的应用提供了理论依据.     

Effect of ligation on internal carotid artery blood pressure in horses

The effect of a single ligature on back pressure in the internal carotid artery was studied in nine horses. In six anesthetized horses, one internal carotid artery was catheterized 2 cm from its origin and blood pressure was recorded continuously. Then the artery was ligated, pressure was recorded again, and the horses were euthanatized. In another three anesthetized horses, indwelling catheters were placed in both internal carotid arteries and a loose ligature was placed proximal to one catheter. After horses recovered from anesthesia, the ligature was tied and blood pressure was recorded in both arteries on that day and 3 days later, then these horses were euthanatized. The anatomy of the cerebral arteries was examined in all nine horses. Blood pressure in the internal carotid arteries did not change after ligation. Subjectively, collateral channels considered most likely to maintain blood pressure in the ligated internal carotid artery were the caudal intercarotid artery and the cerebral arterial circle. We concluded that ligation of the internal carotid artery would not prevent severe hemorrhage from the internal carotid artery in horses with guttural pouch mycosis until the ligated artery thrombosed to the level of the lesion.     

Effect of cardiac dysrhythmia on cerebral perfusion

Extracranial carotid arterial obstructive disease has been the entity most commonly associated with transient cerebrovascular insufficiency. A nonobstructive, frequently overlooked cause of cerebral ischemia is cardiac dysrhythmia. We have explored this by observations of experimental animals and of man. Blood flow and pressure in the carotid arteries of dogs were shown to be decreased by mechnically induced premature ventricular contractions. The significance of the cardiogenic contribution to altered cerebrovascular perfusion was studied by ocular and brachial plethysmography in 210 patients suspected by history of having carotid arterial insufficiency. Of the 210 patients, 62 demonstrated abnormal ocular plethysmographic recordings, and of those, nine had dysrhythmias associated with significant deficits of ocular perfusion. Five patients whose recordings were technically suitable for publication are presented to demonstrate the bizarre ocular plethysmographic recordings seen during the dysrhythmic cycle.