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Results for “Monitoring, Intraoperative”

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At least 505 records · Page 28Linked to original sources

PubMed2003

Intraoperative TEE monitoring on pulmonary thromboembolectomy--a case report.

We present a successful thromboembolectomy under intraoperative transesophageal echocardiography (TEE) monitoring on a woman with massive pulmonary embolism (PE). Sudden onset of dyspnea happened 7 days after lumbar spine surgery and ventilation/perfusion scan and angiography performed right away were suggestive of PE. Operation was performed 17 days later after invalid anticoagulant treatments and unavailing catheter fragmentation. Intraoperative TEE showed massive emboli in the main and right pulmonary arteries (MPA and RPA) and dilated right atrium (RA) with deviated intraatrial septum. Removal of the emboli was performed smoothly under TEE monitoring. The dilation of RA, right ventricle (RV) and PA were resolved soon after thromboembolectomy. The patient was extubated the next day with obvious improvement of clinical symptoms and discharged two weeks later without neurological sequale. We conclude that TEE can be an excellent tool not only for early diagnosing PE in high risk patients but also for intraoperative monitoring on removing emboli and managing cardiac functions.

Echocardiography, Transesophageal↗

PubMed1994

Intraoperative duplex monitoring of the carotid bifurcation for the detection of technical defects.

OBJECTIVES: Intraoperative Duplex examination can be used to identify technical imperfections during carotid endarterectomy. The objectives of this study were: (1) to evaluate the technical feasibility of intraoperative Duplex; (2) to compare Duplex findings with contrast arteriography; (3) to correlate intraoperative Duplex findings with postoperative complications and with Duplex data obtained during follow-up. DESIGN: Prospective clinical study. SETTING: Department of Vascular Surgery, Catharina Hospital, Eindhoven, The Netherlands. MATERIALS: 44 patients underwent Duplex scanning at the completion of carotid endarterectomy. In addition intraoperative arteriography was performed in the first 16 consecutive patients. Follow-up included a Duplex examination at three monthly intervals during the first postoperative year. OUTCOME MEASURES: Technical defects and flow disturbance at the time of surgery, and postoperative restenosis. RESULTS: At contrast arteriography a distal intimal ridge with 15-20% diameter reduction was observed in two, an occlusion of the external carotid artery in three and moderate kinking in one patient. All abnormalities were identified at Duplex imaging. In none of the cases were the Duplex findings considered an indication to re-explore the endarterectomised internal carotid artery. Postoperative complications occurred in six patients: three strokes, two transient ischaemic attacks and two internal carotid occlusions (in one patient combined with a stroke). Severe spectral broadening (spectral class D) correlated significantly with early postoperative complications (p = 0.027). In contrast, moderate defects on Duplex imaging did not correlate significantly with early complications. Duplex examination during the first year of follow-up demonstrated recurrent stenosis in four patients. Intraoperative spectral broadening did not correlate significantly with the development of common or internal carotid restenosis. However, external carotid recurrent stenosis was positively related to intraoperative flow disturbance (p = 0.0003). CONCLUSION: Duplex scanning is easy to use after completion of carotid endarterectomy. There is good agreement between intraoperative Duplex scanning and contrast arteriography. Extensive spectral broadening of the Doppler velocity signal is associated with an increased prevalence of early postoperative complications. Restenosis at follow-up appears to be related to severe flow disturbance as was demonstrated for the external carotid artery.

Blood Flow Velocity↗

PubMed1991

Intraoperative electrocochleographic monitoring of inner ear surgery for endolymphatic hydrops. A review of cases.

The purpose of this review of cases was to determine whether or not the SP/AP amplitude ratio changes during unidirectional inner ear valved shunt surgery for the decompression of the hydropic labyrinth in Meniere's disease. A series of 62 patients underwent shunt surgery over a 20 month period. In 43 cases (43 ears), ECoG responses were successfully recorded throughout the duration of surgery. A pair of two-tailed paired t-tests were computed for SP/AP amplitude ratios acquired during intraoperative ECoG monitoring at the baseline and closing stage of surgery. The first t-test compared the mean SP/AP amplitude ratios at baseline and closing for those cases in which the SP/AP amplitude ratio at baseline was abnormal (baseline > 35%). The t was significant, t(19) = 4.63, p < 0.01). The second t-test compared the mean SP/AP amplitude ratios at baseline and closing for those cases in which the SP/AP amplitude ratio at baseline was WNL (baseline < or = 35%). The t was insignificant, t(20) = 0.31, p > 0.05. Variations between baseline and closing measurements were categorized as either a reduction, no change (very stable over time), or an increase in the SP/AP amplitude ratio. A change in the SP/AP amplitude ratio from baseline to closing of > or = 7% (x = 2%, SD = 2%) was considered statistically significant. Overall (43 cases), 49% of the variations fell into the no change category, with 42% and 9% of the cases placed in the reduction and increase categories, respectively. Of the cases (22) in which the baseline measurement was outside the limits of normal, 64% showed a reduction, 32% showed no change, and 4% showed an increase in the SP/AP amplitude ratio at closing. Changes in the SP/AP amplitude were observed at various stages of the surgical procedure. Reductions were found at each of the five surgical steps identified, with the majority of the changes almost evenly divided between the stages of mastoid drilling and opening sac. Increases in the SP/AP amplitude ratio were found in four cases. The increases were observed during drilling of the mastoid bone in two cases and sac decompression and opening the sac in the remaining cases.

Acoustic Stimulation↗

PubMed1986

Preoperative localization and intraoperative glucose monitoring in the management of patients with pancreatic insulinoma.

Whipples triad of hypoglycemic episodes associated with fasting blood sugar levels of less than 50 milligrams per 100 milliliters with relief of the symptoms by the administration of glucose intravenously leads to the clinical diagnosis of insulinoma. This diagnosis can be confirmed in a laboratory by the biochemical measurement of an inappropriate insulin elevation in response to fasting or the infusion of calcium or tolbutamide. Since more than 90 per cent of the tumors are benign, the potential for operative cure is high. Unfortunately, because of multicentricity (12 to 13 per cent) and the frequent small size of the tumor, some series report 15 to 30 per cent of inadequate or failed operations. Preoperative localization, in most centers, has depended upon sonography (positive in one of six patients in our series), computerized tomographic scanning (positive in one of five patients), celiac axis angiography (positive in six of 15 patients) and transportal venous sampling for insulin levels (positive in 11 of 13 patients in our series). We found that the combination of arteriography and transportal sampling has been the most accurate means of precise preoperative localization. In conjunction with preoperative localization, we have used intraoperative monitoring of glucose levels as a guide to the completeness of resection of insulin producing tumors. Sustained elevation of blood glucose levels has confirmed the adequacy of surgical intervention. Failure of the blood sugar level to increase had led to the successful search for additional tumors not identified preoperatively or to further resection. The combination of arteriography, transportal sampling and monitoring of glucose levels has led to the cure of 15 patients operated upon at the Mount Sinai Hospital from 1977 to 1984.

Adenoma, Islet Cell↗

PubMed1988

[Recently experienced ten cases of insulinoma--preoperative diagnosis of localization and intraoperative simultaneous monitoring of glucose and insulin].

We have experienced 10 cases of insulinoma during the last 10 years from 1977 to 1986. All cases had strong hypoglycemic symptoms such as disturbance of consciousness, and insulinoma still tended to be misdiagnosed as epilepsy. The diagnosis of insulinoma was easily available from serum IRI (immunoreactive insulin)/plasma glucose ratio in all of the ten cases. As preoperative procedures for the diagnosis of localization, arteriography, computed tomography and portal blood sampling were positive in 6 of 8, 4 of 6 and 2 of 2 patients, respectively. At operation, all insulinomas could be identified by digital palpation. We performed simple excision of the tumor in 6 patients and distal pancreatectomy in 4 patients. The tumors were solitary and benign in all patients, ranging in size from 1.0 cm to 4.5 cm. Three cases were presented as case reports. In these cases, portal blood sampling and/or intraoperative monitoring of plasma glucose and serum IRI were performed. Portal blood sampling was effective even for a case which was negative in image diagnostic procedures. Furthermore, simultaneous monitoring of plasma glucose and serum IRI by quick radioimmunoassay seemed to be a good guide to the completeness of resection of insulin producing tumors.

Adenoma, Islet Cell↗

PubMed2004

Intraoperative auditory monitoring in vestibular schwannoma surgery: new trends.

OBJECTIVE: To investigate the efficiency of a new method of brainstem auditory-evoked potential (BAEP) monitoring during complete vestibular schwannoma (VS) resection with attempted hearing preservation. MATERIAL AND METHODS: Dedicated software providing near real-time recording was developed using a rejection strategy of artifacts based on spectral analysis. A small sample number (maximum 200) is required and results are obtained within 10 s. Fourteen consecutive patients with hearing class A operated on for VS, in an attempt to preserve hearing, participated in the investigation. Postoperatively, 7 patients (50%) had useful hearing (hearing class A, 4/14; hearing class B, 3/14) on the operated side. Seven patients (50%) were reduced to hearing class D. RESULTS: Drilling of the internal auditory canal (IAC) and tumor removal at the lateral end of the IAC were identified as the two most critical steps for achieving hearing preservation. Intraoperative BAEP monitoring was sensitive in detecting auditory damage with useful feedback but its effectiveness in preventing irreversible hearing impairment was not demonstrated in this study. CONCLUSION: Combined BAEP and direct auditory nerve monitoring using the same equipment will be performed in the future in an attempt to enhance the chances of preventing irreversible hearing damage, and possibly to improve the hearing outcome significantly.

Adolescent↗

PubMed2000

[Rheographic monitoring of intraoperative hemodynamics].

The authors summed up the experiences with using noninvasive monitoring of hemodynamics during 420 operations. The method was based on computed procession in the real time of the integral rheogram of the body. The advantages, shortcomings and technological details of the method were analyzed.

Anesthesia, General↗

PubMed1988

Intraoperative electrophysiologic monitoring of laryngeal muscle during thyroid surgery.

A technique is described for intraoperative electrophysiologic monitoring of laryngeal muscles. This technique has been used to identify the laryngeal nerves during surgery for recurrent tumors of the thyroid gland, when direct visualization of the nerves is difficult or impossible. Laryngeal muscle electrical activity is monitored with endoscopically placed wire-hook electrodes inserted into the vocal folds bilaterally. Neurotonic discharges are detected when the recurrent laryngeal nerves are manipulated during surgical dissection. Precise localization of the recurrent nerves is possible using a hand-held bipolar stimulator.

Adenocarcinoma, Papillary↗

PubMed1995

Continuous intraoperative external monitoring of perfusate leak using iodine-131 human serum albumin during isolated perfusion of the liver and limbs.

Regional isolated perfusion using tumor necrosis factor (TNF) shows significant promise for treatment of cancer which is limited to limbs or organs. The high toxicity of TNF requires very sensitive real time monitoring of leakage in order to avoid serious patient complications. Human serum albumin labeled with iodine-131 is used with an externally mounted and collimated NaI(Tl) detector to track the leakage of blood from the isolated perfusion blood circuit into the general systemic vascular space. Blood activity levels measured using the monitor demonstrated a very good correlation with blood serum samples taken concurrently with external monitoring. External monitoring can reduce the risks of perfusion leakage intraoperatively with the precision necessary to safely perform isolated perfusion using TNF.

Chemotherapy, Cancer, Regional Perfusion↗

PubMedDate not supplied

Intraoperative wavefront monitoring during laser thermal keratoplasty.

PURPOSE: Low energy laser thermal keratoplasty (LTK) is being proposed as an alternative to conventional holmium LTK in an effort to minimize corneal tissue necrosis, regression, and induced astigmatism. Real-time wavefront monitoring during surgery is also being proposed as a method for regulating induced aberrations and the treatment end point. We evaluated the feasibility of intraoperative wavefront monitoring during low energy LTK. METHODS: An investigational prototype system combining a Sunrise Hyperion laser with a Shack-Hartmann wavefront sensor (Wavefront Sciences COAS) was used to treat 20 hyperopic eyes with a low energy application of eight spots of 18mJ/shot (144mJ/pulse) at 5 Hz in two rings of 6 mm and 7-mm diameter, while monitoring the treatment with real-time dynamic wavefront sensing up to 10 captures/second of 4th order Zernike data. RESULTS: The integrated wavefront-monitored LTK unit showed good stability in measuring dynamic intraoperative wavefront refractions before, during, and after the low energy LTK treatment. The readings did not interfere with the application of holmium laser pulses, nor did the LTK treatment distort the captured wavefront readings. A steady improvement of the wavefront-derived spherical equivalent refraction followed the laser treatment pattern, with a mean attempted spherical equivalent refractive change of 1.66 D and mean achieved change of 1.71 D. CONCLUSION: Intraoperative wavefront monitoring was feasible during low energy LTK. With future adaptation, it might be possible to dynamically relay the captured wavefront information to the laser during ongoing treatment, to intraoperatively control the surgical endpoint for multiple aberration terms.

Cornea↗

PubMed1985

[Changes in somatosensory evoked potentials in carotid desobliteration. Diagnostic significance and possible consequences for therapy].

The cerebral function of 55 patients with stenosis and occlusion of carotid arteries was monitored intraoperatively by serial examination of somatosensory cortical evoked potentials (SEP). In 40 uncomplicated operations no significant alteration of the SEP was detected. In 13 examination series, however, reversible abnormalities were noted. Furthermore, in two cases irreversible SEP loss was documented. The nature and temporal development of SEP alterations enabled differentiation of possible etiological factors. Bilateral abnormalities were indicative of global hypoxemia whereas acutely arising unilateral SEP loss suggested embolic occlusion of cerebral arteries. Intraoperative SEP monitoring therefore appears to be of diagnostical and differential diagnostical value and allows statements in respect to further intra- and postoperative treatment.

Brain Damage, Chronic↗

PubMed1994

Differences in the topographical distribution of EEG activity during surgical anaesthesia and on emergence from volatile anesthetics.

Computerized processing of a 16 channel EEG allows mapping and display of cortical electrical activity in a useful mode for intraoperative monitoring. We studied the topographical distribution of EEG-activity displayed as spectral maps comparing inhalational anaesthesia with isoflurane or enflurane during surgical anaesthesia and emergence. Two groups of nine patients each were anaesthetized with one of the two regimens. The EEG patterns during steady state end-tidal concentrations of isoflurane (0.7-1.1%) or enflurane (0.8-1.3%) showed highest activity in the frontal and occipital areas. At near awakening the frontal and occipital dominance of delta activity disappeared in both groups and was replaced by homogeneous delta activity over the entire cortex; variations in the topographical distribution of enflurane and isoflurane were recorded in the other spectral bands. We conclude that changes in topographic EEG patterns observed during the transition from surgical anaesthesia to emergence, in particular the disappearance of frontal and occipital dominance of delta activity common to isoflurane and enflurane, may serve to detect undesirably light levels of anaesthesia.

Adult↗

PubMed1994

An introduction to bispectral analysis for the electroencephalogram.

The goal of much effort in recent years has been to provide a simplified interpretation of the electroencephalogram (EEG) for a variety of applications, including the diagnosis of neurological disorders and the intraoperative monitoring of anesthetic efficacy and cerebral ischemia. Although processed EEG variables have enjoyed limited success for specific applications, few acceptable standards have emerged. In part, this may be attributed to the fact that commonly used signal processing tools do not quantify all of the information available in the EEG. Power spectral analysis, for example, quantifies only power distribution as a function of frequency, ignoring phase information. It also makes the assumption that the signal arises from a linear process, thereby ignoring potential interaction between components of the signal that are manifested as phase coupling, a common phenomenon in signals generated from nonlinear sources such as the central nervous system (CNS). This tutorial describes bispectral analysis, a method of signal processing that quantifies the degree of phase coupling between the components of a signal such as the EEG. The basic theory underlying bispectral analysis is explained in detail, and information obtained from bispectral analysis is compared with that available from the power spectrum. The concept of a bispectral index is introduced. Finally, several model signals, as well as a representative clinical case, are analyzed using bispectral analysis, and the results are interpreted.

Electroencephalography↗

PubMed2004

Controlled hypotension for spinal surgery.

Controlled, deliberate hypotension during anesthesia for major spinal surgery reduces intraoperative blood loss and transfusion requirement. Hypotension may be achieved with increased doses of volatile anesthetic agents or by continuous infusion of vasodilating drugs. Safe application of this technique requires knowledge of the physiology of hemorrhagic shock and close intraoperative monitoring to avoid vasoconstriction and end-organ ischemia.

Anesthetics, Inhalation↗

PubMed2005

Intraoperative prediction of compensatory sweating for thoracic sympathectomy.

OBJECTIVE: Postoperative compensatory sweating (PCS) is an important problem impacting on quality of life for patients after endoscopic thoracic sympathectomy (ETS). The present study investigated whether intraoperative palmar temperature and blood flow are useful for assessing PCS after ETS. METHODS: Retrospectively, results were evaluated for ETS in 27 consecutive patients with primary palmar hyperhidrosis between 1996 and 2002. For all patients, bilateral nerve conduction to the palms was interrupted. The relationship between the range of PCS and intraoperative changes in palmar temperature and blood flow was investigated. RESULTS: PCS developed in all cases. After completion of ETS, mean blood flow and temperature increased respectively. Significant correlations were found between the range of PCS and increases in palmar temperature (p<0.05) and blood flow (p<0.05). CONCLUSION: Intraoperative monitoring of increases in palmar temperature and blood flow may be useful in patients with primary hyperhidrosis, to predict the range of PCS after ETS.

Adolescent↗

PubMed2005

Simultaneous multilobar electrocorticography (mEcoG) and scalp electroencephalography (scalp EEG) during intracranial vascular surgery: a new approach in neuromonitoring.

OBJECTIVE: Intraoperative neuromonitoring for intracranial vascular surgery is primarily aimed at detecting early ischemic changes to prevent subsequent infarction. Despite various neurophysiological approaches detection of early and focal ischemic changes remains difficult. This study explores the feasibility and sensitivity of intraoperative monitoring using surface EEG (scalp EEG) and multilobar Electrocorticography (mEcoG) recording during intracranial vascular procedures. METHODS: About 21 recordings were acquired in 20 patients undergoing craniotomies for intracranial aneurysms (17), superficial temporal-middle cerebral artery bypass (twice in the same patient) and arteriovenous malformation (2). The recording of scalp EEG (needle electrodes) and EcoG was performed (cupules electrodes) during all of the surgery. Signal was visually analyzed online and using spectral analysis software offline. RESULTS: Good recordings were obtained in all cases, without adding any procedural morbidity. The most common abnormalities on mEcoG were high frequency waves (23-37 Hz; HF-beta3), which appeared just after vascular occlusion and were occasionally followed by slow waves or burst suppression pattern. This focal pattern was seen in a majority of cases (20/21) on the mEcoG, but only in 4 out of 21 cases on the EEG. CONCLUSIONS: Multi-lobe (mEcoG) recording is feasible during craniotomies and detects earlier and more EEG pattern variation than surface EEG monitoring during intracranial vascular manipulations. The authors discuss the high sensitivity of this technique to ischemic changes. SIGNIFICANCE: By detecting earlier and more focal changes than scalp EEG, mEcoG may favor during surgery an increase in interactive strategies and reduction of deleterious event.

Adult↗

PubMed2005

Vestibular evoked myogenic potentials induced by intraoperative electrical stimulation of the human inferior vestibular nerve.

Vestibular evoked myogenic potentials (VEMPs) can be recorded from sternocleidomastoid muscle (SCM) in clinical practice. The aim of the present study was to investigate VEMPs upon direct electrical stimulation of the human inferior vestibular nerve to evidence the vestibulocollic reflex arch and their saccular origin, respectively. Seven subjects were stimulated at the inferior (IVN) and superior (SVN) vestibular nerve. The EMG signals of the SCM were recorded. These recordings were compared to air- and bone-conduction evoked VEMPs with respect to latency and shape. All subjects showed normal VEMPs upon acoustic stimulation with a latency of 12.8+/-1.4 ms for P13, and 22.7+/-2.0 ms for the N23 pre-operatively. Upon direct electrical stimulation of the IVN, the mean latency of the positive peak was 9.1+/-2.2 and 13.2+/-2.3 ms for the negative one. No contralateral SCM response was found. Electrical stimulation of the SVN did not result in any EMG response of the SCM. The study shows experimental evidence of the vestibulocollic reflex by direct electrical stimulation of the human IVN for the first time. The method can be utilized to map VIIIth nerve subdivisions and to intraoperatively monitor IVN integrity in a real-time mode.

Acoustic Stimulation↗

PubMed2005

Anesthetic choices in surgery.

Advances in technology and pharmacology continue to change techniques for anesthesia. So-called "fast-track" anesthesia has led to the development of new anesthetic agents and changes in anesthetic practice, including the increased use of regional anesthesia, techniques involving continuous plexus catheters to improve postoperative analgesia, and total intravenous anesthesia. Technological advances now provide additional options for airway management when a difficult airway is encountered. Advances have also produced additional intraoperative monitoring through the use of depth-of-anesthesia monitors and transesophageal echocardiography. Future areas of development are likely to include target-controlled infusion pumps as well as techniques and medi-cations that improve fast-track anesthesia safely.

Anesthesia↗