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Biomedical subjects

W Gee

Publications and source records attributed to W Gee.

At least 37 records · Page 2Linked to original sources
PubMed1987

Accessory nerve injury during carotid endarterectomy.

Injury to the accessory nerve (cranial nerve XI) during carotid endarterectomy is rare; to date only three cases have been reported in the literature. Traction on the sternocleido-mastoid muscle was the proposed mechanism of injury in all three cases. Four cases of accessory nerve palsy occurred in 850 carotid endarterectomies performed between 1978 and 1986 at this institution, an incidence of 0.47%. All four patients had classic signs and symptoms of accessory nerve injury, which developed between 20 and 60 days after operation. The three most recent cases were examined specifically for accessory nerve injury in the immediate postoperative period and exhibited normal trapezius function. None had any other central nervous system dysfunction. Two of these patients regained full accessory nerve function and the most recent case is showing signs of reinnervation with conservative therapy. Isolated central nervous system and spontaneous accessory nerve palsies are exceptionally rare, and since any traction injury or transection should have been detected by postoperative examinations in three of four patients, we propose surgical scar formation as a mechanism of accessory nerve palsy after carotid endarterectomy. If such a palsy develops in the postoperative period, we recommend conservative therapy.

Accessory Nerve Injuries↗
PubMed1986

Physiology of carotid endarterectomy with ocular pneumoplethysmography.

Objective documentation of the quantitative physiologic changes associated with the repair of carotid lesions of hemodynamic consequence was obtained in 701 procedures by a comparison of pre- and postoperative ocular pneumoplethysmographic tests (OPG-Gee). The results of repair of severe stenoses depended on the status of the carotid artery opposite the repaired vessel. If the vessel opposite the carotid artery repaired was functionally patent, severely stenosed, or totally occluded, the ocular blood flow improvement on the side of repair was 16%, 27%, and 47%, respectively. Only in the latter group was improvement in ocular blood flow observed on the side opposite the carotid repair (13%). Ocular blood flow, the bulk of which (choroid) is not autoregulated, is a much more sensitive indicator of carotid lesions of hemodynamic consequence than is the autoregulated cerebral blood flow. OPG-Gee is presented as a simple noninvasive test that reliably and reproducibly assesses the quantitative physiologic changes associated with the repair of carotid lesions of hemodynamic consequence. The latter represent 84% of all carotid endarterectomies at this institution.

Arterial Occlusive Diseases↗
PubMed1986

Assessment of intra-aortic balloon pumping by ocular pneumoplethysmography.

The ocular pneumoplethysmograph (OPG-Gee) has been used to screen for unsuspected carotid disease in candidates for cardiac operations. This article demonstrates that the validity of such screening is maintained, even if the patient is sustained by an intra-aortic balloon pump (IABP). An unexpected observation is the apparent reduction of ocular blood flow during IABP, which was reduced in this series of 56 patients by an average of 11.6 per cent.

Blood Circulation↗
PubMed1986

Reappraisal of ocular pneumoplethysmography after carotid endarterectomy.

An initial report documented a 3-year experience (1978 through 1980) with ocular pneumoplethysmography (OPG-Gee) done in the recovery room after carotid endarterectomy. The present report analyzes a similar 4-year experience (1981 through 1984) on 864 carotid endarterectomies performed by 20 surgeons in which the results of OPG tests done in the recovery room suggested carotid endarterectomy thromboses in 33 of the 864 patients (3.8%). All patients underwent immediate reoperation, and thromboses were confirmed in 26 of the 33 patients (79%). In the seven patients without thromboses, findings at reoperation accounted for the abnormal physiology in six of the seven patients. Overall, in 32 of the 33 patients (97%) the recovery room OPG tests accurately reflected a source of hemodynamic compromise. The application of the special OPG-Gee criteria in this report will minimize needless reoperation after carotid endarterectomy.

Anesthesia Recovery Period↗
PubMed1985

Primary structure and gene organization of human hepatitis A virus.

The RNA genome of human hepatitis A virus (HAV) was molecularly cloned. Recombinant DNA clones representing the entire HAV RNA were used to determine the primary structure of the viral genome. The length of the viral genome is 7478 nucleotides. An open reading frame starting at nucleotide 734 and terminating at nucleotide 7415 encodes a polyprotein of Mr 251,940. Comparison of the HAV nucleotide sequence with that of other picornaviruses has failed to reveal detectable areas of homology. However, a computer analysis of the putative amino acid sequence of HAV and poliovirus demonstrated the existence of short areas of homology in virion protein 3 (VP3) and throughout the carboxyl-terminal portion of the polyproteins. In addition, extensive protein structural homologies with poliovirus were detected.

Amino Acid Sequence↗
PubMed1983

The collateral hemispheric systolic pressure.

Satisfactory calibrated BP tracings were obtained during 385 (85%) of 455 carotid endarterectomies. The pressures were measured from the distal common carotid arteries while the external carotid arteries were clamp occluded. Continuous recordings were made with and without proximal common carotid clamp occlusion. The two systolic pressures resulting in each patient were plotted as a single point on a graph, with the direct carotid systolic pressure on the abscissa and the back carotid systolic pressure on the ordinate. Formulae of the mean values in 101 of the 385 procedures, in which the opposite carotid systems contained severe stenoses or total occlusions, and the other 284 procedures, in which the opposite carotid systems had no notable lesions, demonstrate that the collateral hemispheric systolic pressure depends on the status of the opposite carotid artery and on the central BP. We derived formulae for these two groups of patients to demarcate the lowest collateral hemispheric systolic pressure adequate for hemispheric integrity during and following prolonged operative carotid occlusion or following permanent interruption of carotid blood flow as a result of thrombosis, ligation, or resection without graft replacement.

Arterial Occlusive Diseases↗
PubMed1983

Ocular pneumoplethysmography in cardiac pacing.

Variations in ocular blood flow (OBF) reflect variations in cardiac stroke output very closely. The use of ocular pneumoplethysmography (OPG-Gee) for the measurement of OBF is a simple, noninvasive method of assessing the hemodynamics of ventricular versus atrioventricular sequential pacing.

Arrhythmias, Cardiac↗
PubMed1983

Ocular pneumoplethysmography in carotid-cavernous sinus fistulas.

Pulsatile exophthalmos in association with carotid-cavernous sinus fistulas has been well defined anatomically, by angiography. This paper presents the physiological assessment of this entity, as measured with ocular pneumoplethysmography (OPG-Gee). The abnormal arteriovenous communication lowers resistance to arterial flow. This is characterized by a lowered ophthalmic systolic pressure and an increased ocular blood flow. The OPG readily documents the physiological result of therapeutic intervention.

Arteriovenous Fistula↗
PubMed1983

Ocular pneumoplethysmography in head-injured patients.

Severe head injury is frequently associated with multiple trauma. In the comatose patient, endotracheal intubation and ventilator support are often required, if there is associated dyssynchronous spontaneous effort. The latter is managed with therapeutic (drug) paralysis. An elaborate life-support and monitoring system coupled with controlled paralysis limits the mobility of the patient for diagnostic procedures, and a continuing reevaluation of neurological status is difficult. Under these circumstances the ocular pneumoplethysmograph provides a simple rapid noninvasive assessment of ocular blood flow, and this reflects cerebral blood flow and alterations in brain compliance. Alterations in the therapeutic regimen can be based on these observations.

Brain Injuries↗
PubMed1981

Extracranial surgery for the low-flow-endangered brain.

Angiography documented severe (greater than 75%, cross-sectional area) bilateral carotid stenotic or occlusive disease in 60 patients. One third of these patients were thought to have transient ischemic symptoms of low-flow rather than embolic etiology. Preangiographic ocular pneumoplethysmography (OPG-Gee) was obtained in all patients. Postoperative OPG studies were obtained in the 39 patients who underwent unilateral carotid surgery. In seven of the 39 patients who were operated on, bilateral procedures were performed; OPG studies were obtained after the second procedure also. Comparison of the preoperative and postoperative OPG studies provided convincing evidence that the establishment of major carotid inflow should be the primary objective in patients with severe bilateral carotid disease, and that distal extracranial-intracranial reconstruction should be reserved for patients failing to respond to augmented inflow because of deficient collateral vessels.

Blood Pressure↗
PubMed1981

Postendarterectomy carotid occlusion.

In a prospective study of 300 carotid endarterectomies, ocular pneumoplethysmography (OPG-Gee) was performed in the recovery room after all procedures. Positive test findings, indicative of occlusion of the repaired vessels, were encountered after 16 (5%) of these procedures, and all 16 patients were completely asymptomatic. Serial test results, without angiographic confirmation, have remained positive in nine. Angiography confirmed the positive test results in three. Immediate reoperation, without angiography, confirmed the positive test findings in four, and normal flow was restored in all four cases. Success of carotid endarterectomy should not be measured by absence of symptoms. Objective documentation of persistent patency is essential. Present policy dictates that if recovery room test results are positive, the patient be returned to the operating room as soon as possible, with no delay for angiography.

Blood Pressure↗
PubMed1980

Carotid stenosis plus occlusion: endarterectomy or bypass?

In 15 patients with unilateral internal carotid artery occlusion and contralateral internal carotid artery stenosis of pressure significance (75% cross-sectional area or greater), the ocular pneumoplethysmograph (OPG-Gee) has documented bilateral improvement in the ophthalmic systolic pressure in 12/15 patients who underwent endarterectomy of the stenosed carotid artery as the sole operative procedure. External carotid to internal carotid shunt on the side of the internal carotid occlusion need be entertained only in those patients who remain symptomatic on the side of the internal carotid occlusion after contralateral stenosis endarterectomy.

Arterial Occlusive Diseases↗
PubMed1980

Spontaneous dissection of internal carotid arteries. Spontaneous resolution documented by serial ocular pneumoplethysmography and angiography.

Spontaneous dissection of the internal carotid artery can appear on an angiogram as a total occlusion of this vessel. This appearance differs from that typical of atherothrombotic occlusion. In four patients with spontaneous dissections of internal carotid arteries, serial ocular pneumoplethysmography demonstrated spontaneous restoration to functional patency. Repeated angiography confirmed the noninvasive testing in all four patients.

Carotid Artery Diseases↗