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Results for “Monitoring, Intraoperative”

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At least 1,153 records · Page 64Linked to original sources

PubMed2002

Axonal injury in auditory nerve observed in reversible latency changes of brainstem auditory evoked potentials (BAEP) during cerebellopontine angle manipulations in rats.

Intraoperative monitoring of brainstem auditory evoked potentials (BAEP) has been widely utilized to reduce the incidence of postoperative hearing disturbance due to cerebellopontine angle manipulations. The prolongation of wave V of BAEP is usually used as a criterion to warn the surgeons to modify their surgical maneuvers. However, it is not known whether all neuropathological changes are avoided if BAEP latency intraoperatively returns to the baseline level or some neuropathological changes 'silently' occur even if BAEP normalizes. The aim of this study was to experimentally clarify this point that would be important for the long-term prognosis of patients' hearing. The cerebellopontine angle portion of the auditory nerve was quantitatively compressed in the rats and reversible prolongation of BAEP latency was reproduced just as it occurs during surgery in humans. Twenty-four hours after the compression, the auditory nerve was removed for beta-APP immunostaining to investigate the degree of axonal injury. The results of the present study disclosed that axonal injury occurred even in the cases where the intraoperative normalization of prolonged wave IV (equivalent to wave V in humans) latency had been obtained. Therefore, the interpretation of BAEP changes based only on the prolongation of the latency of BAEP was not enough to prevent the auditory nerve from developing morphological changes. Changes in the amplitude of wave V of BAEP appears to be more sensitive than its latency change as an intraoperative indicator for axonal injury in the auditory nerve.

Amyloid beta-Protein Precursor↗

PubMed1992

Propofol-fentanyl versus midazolam-fentanyl: a comparative study of local sedation techniques for cataract surgery.

Administering intravenous sedation in conjunction with intraoperative monitoring to cataract surgery patients is a widely accepted technique. Numerous articles report local sedation techniques for cataract surgery that are, in essence, abbreviated general anesthetic techniques for insertion of the retrobulbar block (RBB). Because of variations in levels of consciousness, a number of complications have been encountered with this specific patient population, ie, movement upon insertion of the RBB, intraoperative patient movement, confusion, hypotension, respiratory depression, and respiratory arrest. In an attempt to meet the specific needs of this patient population, a study comparing propofol-fentanyl with midazolam-fentanyl was initiated. Seventy-five (ASA 1 to 3) patients were randomly assigned to two groups: propofol-fentanyl (P/F) or midazolam-fentanyl (M/F). The mean age of patients in the P/F group was 71.1 +/- 13 SD, and the mean age in the M/F group was 74.4 +/- 8.8 SD. All patients entered the operating room unpremedicated. Before the RBB, patients in both groups were given a single intravenous dose of 50 micrograms fentanyl. Propofol (mean dose, 24.7 mg) or midazolam (mean dose, 1.58 mg) was then titrated to slurred speech or nystagmus. Patients' responses to the RBB were evaluated and recorded by an objective observer. The amnestic properties of both agents were evaluated by patient questioning at 10 minutes and 24 hours. Levels of discomfort were evaluated on a scale of 1 to 5, with 1 being extremely uncomfortable and 5 being noticeable without pain. Respiratory depressant effects of both techniques was assessed via continuous pulse oximetry. Results were analyzed using the chi 2 test, rank t test, and SD.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1985

Foetal monitoring in parturients undergoing surgery unrelated to pregnancy.

Foetal heart rate and tocodynamic monitoring of the uterus was performed in five pregnant patients undergoing urgent or emergency surgery unrelated to their pregnancy. All received general anaesthesia with halothane or enflurane and nitrous oxide. The loss of beat-to-beat variation of the foetal heart rate was observed in all patients under general anaesthesia, and is probably normal for the anaesthetized foetus. Since continuous intraoperative monitoring of foetal heart rate in pregnant patients is technically feasible during peripheral surgery and during many intra-abdominal procedures, attempts should be made to monitor foetal heart rate in all anaesthetized parturients to assure that the anaesthetic is not causing foetal insult. Postoperative monitoring of uterine tone is useful in the diagnosis and treatment of postoperative premature labor.

Adolescent↗

PubMed1998

Hemodynamic and pulmonary changes during and after laparoscopic cholecystectomy. A comparison with traditional surgery.

BACKGROUND: The cardiopulmonary changes experienced by patients who undergo laparoscopic cholecystectomy (LC) and the prognostic value of patient characteristics are not well understood. METHODS: Cardiorespiratory changes were investigated in 120 patients undergoing LC or open cholecystectomy (OC). The results and their relation to patient variables were statistically evaluated. RESULTS: The most significant cardiorespiratory changes were (A-a)PO2 increase during OC; decrease of pH and compliance and increase of peak airway pressure during LC; impairment of arterial blood gas mean values and respiratory muscle strength; atelectasis and pneumonia (five cases) after OC; and lamellar atelectasis (two cases) after LC. Significant adverse prognostic factors related to intra- and postoperative LC cardiorespiratory changes were ASA class greater than I, FEF75-85% < 900 ml, and PaO2 < 10.4 kPa (PPV, 71.4% and 46.6%, respectively). CONCLUSIONS: LC carries no significant cardiorespiratory changes provided that intraoperative monitoring of hemodynamics and respiratory parameters is done for the study of blood gas values in all patients at risk.

Carbon Dioxide↗

PubMed1984

Intraoperative lymph scintigraphy during radical surgery for cervical cancer.

Intraoperative lymph scintigraphy during radical surgery for cervical cancer was developed in the course of a program covering three periods. During the last period technetium-99m antimony sulfide has been used to visualize pelvic lymph nodes. Surgery is done with a modified gamma camera serving as an operating table. This ensures intraoperative monitoring and greater thoroughness of lymphadenectomy. The introduction of the technique has improved the rate of total lymphadenectomies and has increased both the yields of involved nodes and the 3-yr survival rates.

Antimony↗

PubMed1999

Selective Cerebral Perfusion Via Innominate Artery in Aortic Arch Replacement Without Deep Hypothermic Circulatory Arrest.

To attain satisfactory results in aortic arch surgery a reliable method of cerebral protection, avoidance of emboli, and control of hemorrhage is mandatory. Deep hypothermic circulatory arrest is the most common technique at present but gives only a limited period of protection, whereas a complicated aortic arch operation may require more time than anticipated. Therefore the selective cannulation and perfusion of the innominate artery has not been widely used until now because it is uncertain whether the left hemisphere of the brain is adequately perfused. Between 1990 and 1995, 21 of 69 patients within the last 36 months, consisting of 15 men and 6 women averaging 45 +/- 13.4 years, underwent operative treatment for aneurysm (n = 9) or type A dissection (n = 12) involving the aortic valve and aortic arch; selective innominate perfusion (SCP [i]) in moderate hypothermia (28 degreesC) for brain protection was used. Extended perioperative monitoring included bilateral somatosensory-evoked potentials (SEP), transcranial Doppler sonography (TCD), a computer-aided topographical electro-encephalometry (CATEEM), and analysis of the arterial and venous oxygen saturation and desaturation. Mean time periods were 229.7 +/- 56.5 minutes for extracorporeal circulation, 151.7 +/- 34.1 minutes for aortic cross-clamping, and 67.05 +/- 34.03 for selective cerebral perfusion via the innominate artery. Not once did the intraoperative monitoring reveal hints of cerebral damage due to inadequate perfusion. All patients survived surgery but two could not be weaned from the respirator; one died 2 days and the other 6 days after the operation due to multiple organ failure (MOF). Another two patients died after 13 days due to untreatable septic syndrome with pulmonary insufficiency. All four patients died within 30 days, during which time they had aortic dissection involving the complete aortic arch and severe aortic valvular incompetence (grade IV). There was no late death and follow-up time of 19.76 +/- 8.04 months revealed an overall mortality rate of 19%. Only temporary neurological affections (left-sided hemiparesis) were found in two patients (9.5%). Additionally, we observed neuropsychological disturbances in one of these. Our first experience with selective cerebral perfusion via innominate artery and the attendant CATEEM monitoring for assessment of adequate bilateral cerebral perfusion suggests that this method is a useful addition to the armamentarium in complicated aortic arch surgery.

Journal Article↗

PubMed2005

[Intraoperative laser doppler flowmetry of the tissue microcirculation of extraperitoneal transplanted omental flaps on dogs].

The aim of this study was to develop a new method to check of the viability of an extraabdominally transplanted omental flap. We performed free omental transplantation to the left lateral neck region in the frame of a formerly published new esophageal resection series on 5 dogs. Intraoperative laser Doppler flowmetry was performed, before and after isolation, after transplantation, and 14 days after the operation. From the 5 transplanted flaps, 4 survived the transplantation. The flap microcirculation deteriorated immediately after the transplantation, but at the time of re-operation the measurements showed similar microcirculation as control tissues, which proves the viability of the transplanted flaps. In our opinion, in dogs for the intraoperative monitoring of viability and microcirculation of free transplanted omental flaps, laser Doppler flowmetry is a feasible method.

Animals↗

PubMed1997

[The characteristics of the anesthesiological support for surgical interventions in patients earlier operated on the heart].

The article presents an analysis of the authors' experiences with anesthesiological maintenance of operations on patients after revascularization of the myocardium, implantation of permanent cardiostimulant and heart value prosthesis. Main risk factors responsible for severe complications were found to be congestive heart failure, myocardial infarction which took place 6 months before the operation, certain forms of arrhythmias, unstable stenocardia, pronounced stenosis of the aortic valve, age older than 70 years, diabetes mellitus. The comprehensive preoperative preparing, choice of the adequate methods of anesthesia and maintenance of the up-to-date intraoperative monitoring create the conditions for a less risk of the surgical treatment.

Anesthesia↗

PubMed1994

Changes in directly recorded cochlear nerve compound action potentials during acoustic tumor surgery.

Damage to labyrinthine, neural, and vascular structures may possibly account for failure to achieve hearing preservation after removal of small acoustic neuromas. The pathogenesis of auditory impairment is, however, sometimes unclear. Intraoperative monitoring of auditory evoked potentials enables us to study possible correlations between surgical maneuvers and the function of auditory structures and pathways. To this end, simultaneous recording of brainstern auditory evoked potentials and direct cochlear nerve action potentials (CNAPs) was utilized in 14 patients with small (12 to 18 mm) unilateral acoustic neuromas. The latency of the first negative component (N(1)) of the CNAPs proved extremely sensitive in detecting intraoperative auditory damage and was a good predictive index of postoperative auditory outcome. Evaluation of temporal and morphologic CNAP patterns allowed identification of coagulation close to the cochlear nerve, drilling of the internal auditory canal, and removal of the intrameatal portion of the tumor, the most critical steps in hearing preservation. The mechanisms of damage are analyzed and discussed.

Journal Article↗

PubMed1989

[Function-saving microsurgery in suboccipital removal of large acoustic neuromas].

Various successful approaches are available for acoustic neurinoma surgery, permitting total tumor removal and preservation of cranial nerve function. In smaller and medium sized tumors excellent results can be achieved with respect to facial and cochlear nerve function using the transtemporal approach. For larger tumors similar results can be achieved by the suboccipital approach. The results of 45 completely removed large acoustic neurinomas all operated upon via the suboccipito-lateral approach with microsurgical techniques and neurophysiological monitoring are presented. The average tumor size, excluding the portion within the internal auditory canal was 3 cm. Anatomical preservation of the VIIth cranial nerve was achieved in nearly all cases. Satisfactory to excellent facial nerve function was preserved in 70% of all cases. Initial hearing was preserved in 29%. However delayed postoperative hearing loss was encountered in 13%. Therefore definite hearing preservation was achieved in 16% of the cases. Intraoperative monitoring, especially of auditory evoked potentials, was very helpful in achieving these functional results.

Adult↗

PubMed2005

Imaging of somatotopic representation of sensory cortex with intrinsic optical signals as guides for brain tumor surgery.

OBJECT: Intrinsic optical signals in response to somatosensory stimuli were intraoperatively recorded during brain tumor surgery. In the present study, the authors report on the use of this technique as an intraoperative guide for the safe resection of tumors adjacent to or within the sensorimotor cortex. METHODS: In 14 patients with tumors adjacent to or within the sensorimotor cortex, intrinsic optical signals in response to somatosensory stimuli were recorded by illuminating the brain surface with Xe white light and imaging the reflected light passing through a bandpass filter (605 nm). Results were compared with intraoperative recordings of sensory evoked potentials in all 14 patients and with noninvasive mapping modalities such as magnetoencephalography and positron emission tomography in selected patients. In all but two patients, the somatosensory optical signals were recorded on the primary sensory cortex. Optical signals elicited by stimulation of the first and fifth digits and the three branches of the trigeminal nerve were recorded at different locations on the sensory strip. This somatotopic information was useful in determining the resection border in patients with glioma located in the sensorimotor cortex. CONCLUSIONS: Optical imaging of intrinsic signals is a useful technique with superior spatial resolution for delineating the somatotopic representation of human primary sensory cortex. Furthermore, it can be used as an intraoperative monitoring tool to improve the safety and accuracy of resections of brain tumors adjacent to or within the sensorimotor cortex.

Adult↗

PubMed2000

Anesthesia for kidney transplant surgery.

Organ viability associated with renal transplantation is a product of the managing of the donor patient, the allograft, and the recipient patient. Short- and long-term outcome is influenced by perioperative fluid and drug treatment, and the function and viability of the transplanted kidney seem to be optimized if graft perfusion is maximized through mild hypervolemia. At the same time, careful balancing of intraoperative fluids is necessary against cardiovascular problems frequently encountered in patients with uremia. Close intraoperative monitoring, optimization of intravascular fluid volume status to maximize kidney perfusion, and prompt correction of electrolyte disturbances (especially potassium) are key to short- and long-term success of renal transplants.

Anesthesia↗

PubMed1982

Intraoperative sonography for brain tumor localization and ventricular shunt placement.

Intraoperative sonography using portable real-time equipment at the dural or brain surface in 16 patients provided accurate localization of a variety of brain lesions for direct dissectional or needle aspiration biopsies as well as for decompression of cysts. The technique has proven to be reliable and rapid, reducing brain exploration in the search for small or poorly accessible lesions and eliminating complex stereotactic procedures. Ventricular shunt catheter placement was also monitored intraoperatively in two infants.

Adolescent↗

PubMed1991

Randomized study on the effect of collagen impregnation of knitted Dacron velour aortoiliac prostheses on blood loss during aortic reconstruction.

Intraoperative blood loss is an important factor in reconstructive surgery for aortoiliac disease because it is clearly associated with an increase in the operative morbidity and mortality rates. To minimize intraoperative blood loss, a blood-tight vascular prosthesis has been developed by impregnating a knitted Dacron prosthesis with bovine collagen. To study a potential reduction of intraoperative blood loss using these collagen-impregnated prostheses, we conducted a prospective randomized trial involving the collagen-impregnated prosthesis and its non-impregnated substrate, the Dacron knitted non-impregnated prosthesis. During a 2.5-year period, 123 consecutive patients (undergoing 81 procedures for aneurysmal disease and 43 procedures for occlusive disease) were admitted for elective aortic reconstructive surgery. Equal numbers of the two prostheses were randomly implanted. Various parameters were monitored: intraoperative blood loss before aortic cross-clamping (phase 1), during implantation of the prosthesis (phase 2) and after release of aorta cross-clamping (phase 3); the number of intraoperative and postoperative blood transfusions; and, finally, all preoperative and intraoperative factors that might contribute to intraoperative blood loss. A significant overall difference in intraoperative blood loss between the collagen-impregnated (1907 ml) and the non-impregnated (2425 ml) group was found (P = 0.003) [corrected]. However, this difference could not be attributed to collagen impregnation because no statistically significant difference in blood loss was found in the relevant period of operation (phase 3). Similar results were observed in patients operated on for both aneurysmal and occlusive disease (2600 versus 2195 ml and 2105 versus 1344 ml respectively).

Adult↗

PubMed1992

Characteristics of cerebrovascular accidents after coronary artery bypass grafting.

The records of all patients who had a cerebrovascular accident (CVA) following coronary artery bypass surgery were reviewed to determine the incidence, etiology, and outcome following such an event. Between January 1, 1987, and December 31, 1990, 3,428 patients underwent bypass grafting and 46 had a CVA, documented by head computed tomography (CT) after neurologic findings were appreciated, for an incidence of 1.3 per cent. In 16 patients, a neurologic deficit was documented less than 12 hours after surgery and was presumed to have been an intraoperative event. The remaining 30 patients became symptomatic between postoperative days 2 and 7. Twenty-five patients (54%) exhibited neurologic and CT findings suggestive of an embolic event, while the remaining 21 patients appeared to have sustained an infarct as a result of cerebral hypoperfusion. Nine patients with CVA had a carotid bruit documented in the preoperative period, and seven of these suffered their ischemic event in the ipsilateral distribution. Five patients had a documented CVA previously, and four were shown to have extended areas of previous infarction. The mortality following CVA was 35 per cent. Of the survivors, 70 per cent had some improvement in symptoms at the time of discharge; 60 per cent of survivors were discharged to their homes and the remainder to extended care facilities. Although CVA following coronary bypass grafting is an uncommon event, some patients at increased risk may benefit from more aggressive preoperative noninvasive evaluation and intraoperative monitoring. A better understanding of the etiology of postoperative stroke may help to prevent its high morbidity and mortality, which has been demonstrated.

Aged↗

PubMed1992

[Functional results of preservation of cranial nerves in removal of acoustic neurinoma].

Seventeen patients with acoustic neurinoma were reviewed on the basis of postoperative preservation of facial and acoustic nerve functions. The sizes of tumors were intracanalicular in 5 cases, smaller than 20mm in diameter in 2 cases, smaller than 30mm in 5 cases, and larger than 30mm in 5 cases. In all cases, the facial nerve was anatomically preserved at operation. Functional recoveries of the facial nerve in follow-up were excellent in 7 cases out of 17 (41%), good in 5 (29%) and poor in 5 (29%). Although the functional preservation for the facial nerve was related to the size of the tumor, it was favorable in cases of cystic tumor even with a size larger than 20mm. By pure tone audiogram, hearing was found to be preserved in 12 cases before operation. At operation, the acoustic nerve was anatomically preserved in 4 cases. Postoperative hearing was maintained in two cases, one of which showed a successful preservation of serviceable hearing. In this case, tumor resection was performed with intraoperative monitoring of auditory brain stem reactions (ABRs). Discussion was made concerning a possible surgical candidates for the hearing preservation, and it was proposed that every effort should be made to preserve the cochlear nerve if following conditions were verified in the case: 1) normal or nearly normal hearing (less than 40-50dB hearing loss), 2) the size of tumor is intracanalicular or smaller than 2cm in diameter, 3) there is no deterioration of intraoperative ABR.

Adult↗

PubMedDate not supplied

Factors that limit the use of flash visual evoked potentials for surgical monitoring.

A study was conducted comparing the incidence with which the N2/P2/N3 was obtained after flash VEP in 3 groups: anterior visual pathway lesions, non-tumor craniotomies and non-cranial surgery. These groups allowed evaluation of the effects of anesthesia, visual pathway lesions and craniotomy on the stability of the flash VEP. It was found that the latency was not significantly affected in the 3 groups, whereas the incidence of obtainable peaks and the amplitudes were adversely affected by anesthesia, cranial surgical manipulation and especially by the presence of a visual pathway lesion. These adverse effects were so marked that the application of flash VEP for intraoperative monitoring seems of little use.

Brain Neoplasms↗

PubMed1990

Intraoperative awareness due to malfunction of a Siemens 900B ventilator.

A case of intraoperative awareness during a thoracotomy is described. The patient's recall coincided with an intraoperative period during which a Siemens 900B ventilator and a Siemens 952 isoflurane vaporiser were used. Subsequent assessment of this equipment with an anaesthetic agent analyzer revealed that, at the ventilator settings which had been used, the delivered anaesthetic vapour concentration varied greatly from the vaporizer settings. This problem eventually was traced to a malfunctioning inlet control valve on the ventilator. This complication may have been prevented if the end-tidal anaesthetic concentration had been monitored intraoperatively.

Aged↗