PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Monitoring, Intraoperative”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,063 records · Page 59Linked to original sources
PubMed1991

Monitoring of spinal cord stimulation evoked potentials during thoracoabdominal aneurysm surgery.

Repair of a thoracoabdominal aneurysm involves a significant risk of ischemic injury to the spinal cord. Standard monitoring of somatosensory evoked potentials, which relies upon peripheral nerve stimulation, becomes nonspecific and insensitive during this surgery when aortic cross-clamping produces lower extremity ischemia causing a peripheral conduction block. Techniques for the insertion of percutaneous epidural electrodes, developed originally for pain management, have been adapted to this setting to permit direct stimulation of the spinal cord for intraoperative monitoring of evoked potentials. The clinical outcome in patients monitored by this technique has been consistent with evoked potential findings.

Aorta, Abdominal↗
PubMed1987

Anesthetic management of thoracotomy.

Successful anesthesia for thoracic surgery requires an understanding of the clinical disease and the physiologic changes accompanying the disease, as well as anesthetic agents available for use. The authors discuss selection of appropriate anesthetic drugs, perioperative management considerations, pharmacologic support, intraoperative monitoring and postoperative pain management.

Anesthesia↗
PubMedDate not supplied

[Monitoring control of the visual evoked potentials during the surgical treatment of tumors of the chiasmal-sellar area].

Visual evoked potentials were recorded in different stages of the operation in 12 patients with tumors of the chiasmal-sellar region. A correlation was noted between the dynamics of the P100 latent period and the changes of visual functions after the operation. Intraoperative monitoring of visual evoked potentials makes it possible to appraise the functional condition of the optic nerves objectively and correct the techniques and tactics of the operative intervention.

Adenoma↗
PubMed1984

Ultrasonic characteristics of frozen liver.

The recent development of new ultrasound probes has made real-time intraoperative monitoring of cryosurgery, and thermocouple placement a possibility. It is shown that frozen tissue and thermocouple needles have acoustic characteristics that enable them to be easily visualized by ultrasound examination. Further in vivo animal studies are needed to examine temperature characteristics of visualized cryolesions, to develop scanning techniques, and to correlate ultrasonic findings with histologic changes in tissue.

Animals↗
PubMed1990

[Ex situ surgery of the liver--anesthesiologic management].

In a 40-year old patient multiple liver tumours that were otherwise regarded as irresectable were removed in an ex situ operation--according to the authors' knowledge for the first time in a human. After protective perfusion with a hypothermic HTK solution hepatectomy was performed. After extirpation of the tumours ex situ, the residual liver was re-implanted. The total operation time was 13 h 50 min, the anhepatic period lasted for 6 h 9 min. During the anhepatic period a venous bypass shunted the blood from the a femoral and the portal vein to an axillary vein. Considerable blood loss was balanced by the transfusion of 26 units of banked blood. Severe disturbances of blood coagulation could be avoided by early substitution with fresh frozen plasma, platelets and fresh blood. The long anhepatic phase caused an acidosis that required the application of 330 mVal NaHCC3. In the discussion the necessity for an aggressive intraoperative monitoring of haemodynamic and laboratory parameters is emphasized.

Adult↗
PubMed2006

The need for intraoperative parathyroid hormone monitoring during radioguided parathyroidectomy by video-assisted thoracoscopy (VATS).

PURPOSE: We report on a patient with primary hyperparathyroidism (1HPT) who had a preoperative Tc-99m sestamibi scan localizing a single parathyroid adenoma in the mediastinum. METHODS: On removal of this hyperfunctioning adenoma by radioguided video-assisted thoracoscopic surgery (VATS), intraoperative PTH levels failed to decline in the appropriate manner consistent with curative resection. This prompted the surgical team to investigate further for a second adenoma, which revealed a 2 x 1-cm mass near the inferior border of the thyroid gland on the right lateral aspect of the trachea. RESULTS: In the absence of intraoperative PTH monitoring, the operation would have been terminated after the removal of the mediastinal adenoma, leading to an incomplete surgical resection and persistent 1HPT. CONCLUSION: In our patient, curative resection was obtained and a second operation was avoided because of the use of intraoperative PTH monitoring. This case also emphasizes that although VATS was planned, in treating patients with 1HPT, one must also be prepared to perform a neck exploration.

Aged↗
PubMed1984

The application of somatosensory-evoked potentials in orthopedic spine surgery.

This review will report results and experience gained with intraoperative monitoring SSEP's (somatosensory-evoked potentials) during 61 operations on the spine for correction of scoliotic curvatures. The potentials were elicited by uni- or bilateral stimulation of the tibial nerve and recorded from the scalp. Four cases, in which we observed intraoperative or postoperative alterations in waveform or neurologic status, are described. The method is easily applicable, noninvasive, and can--in spite of its sensitivity to environmental influences--well provide information about the neurologic function of the spinal cord.

Adolescent↗
PubMed1999

Intraoperative frozen section monitoring of nerve sparing radical retropubic prostatectomy.

PURPOSE: We describe the clinical and pathological outcomes of intraoperative frozen sections performed on the posterolateral prostate margins during nerve sparing radical prostatectomy. MATERIALS AND METHODS: We developed a technique of bilateral nerve sparing, inking the posterolateral prostate margins and obtaining frozen sections. When tumor was seen on frozen section, the fascia and neurovascular bundle were widely excised before completing the vesicourethral anastomosis. We reviewed 142 radical retropubic prostatectomies performed by a single surgeon between 1992 and 1997. Patients were divided into group 1--nerve sparing procedure using our technique (48 patients), 2--planned unilateral nerve sparing without frozen sections (46) and 3--planned bilateral nerve sparing without frozen sections (48). Potency was measured implicitly by physician assessment and explicitly with the UCLA Prostate Cancer Index. Group comparisons were made for positive margins, biochemical recurrence and potency. Mean followup was 24.5, 43.8 and 39.4 months for groups 1, 2 and 3, respectively. RESULTS: Of the 48 group 1 patients 9 (18%) had adenocarcinoma in the frozen section specimen, prompting wide excision of the bundles. None of these patients had biochemical recurrence during a mean followup of 20.5 months. Both bundles were spared in the remaining 39 patients (82%). There was no difference in survival or time to biochemical recurrence between groups 1 and 2. Potency was significantly different between groups 1 and 2 (36 versus 13%, p = 0.001), even after age adjustment (p = 0.05). In contrast, potency did not differ between groups 1 and 3 (38 versus 40%). Preoperative stage, grade and prostate specific antigen level were similar among the 3 groups. CONCLUSIONS: We found a significant difference in potency rates adjusted for age between patients with and without frozen sections. Our results indicate that this technique can enhance the ability of the surgeon to monitor the nerve sparing procedure without compromising cancer control.

Adult↗
PubMed2000

A new method of intrathecal PO2, PCO2, and pH measurements for continuous monitoring of spinal cord ischemia during thoracic aortic clamping in pigs.

BACKGROUND: Impaired spinal cord circulation during thoracic aortic clamping may result in paraplegia. Reliable and fast responding methods for intraoperative monitoring are needed to facilitate the evaluation of protective measures and efficiency of revascularization. METHODS: In 11 pigs, a multiparameter PO2, PCO2, and pH sensor (Paratrend 7, Biomedical Sensors Ltd, United Kingdom) was introduced into the intrathecal space for continuous monitoring of cerebrospinal fluid (CSF) oxygenation during thoracic aortic cross-clamping (AXC) distal to the left subclavian artery. A laser-Doppler probe was inserted into the epidural space for simultaneous measurements of spinal cord flux. Registrations were made before and 30 minutes after clamping and 30 and 60 minutes after declamping. The same measuring points were used for systemic hemodynamic and metabolic data acquisition. RESULTS: The mean CSF PO2 readings of 41 mm Hg (5.5 kPa) at baseline decreased within 3 minutes to 5 mm Hg (0.7 kPa) during AXC (P < .01). Spinal cord flux measurement responded immediately in the same way to AXC. Both methods indicated normalization of circulation during declamping. Significant (P < .01) changes were also observed in the CSF metabolic parameters PCO2 and pH. CONCLUSIONS: In this experimental model of spinal ischemia by AXC, online monitoring of intrathecal PO2, PCO2, and pH showed significant changes and correlated well with epidural laser-Doppler flowmetry (P < .01).

Animals↗
PubMed1999

[Total intravenous anesthesia with propofol, fentanyl and ketamine for carotid endarterectomy under somatosensory evoked potential monitoring--combination with intraoperative hypothermia].

We reported anesthetic management combined with hypothermia for carotid endarterectomy under somatosensory evoked potential monitoring. Anesthesia was induced by propofol, fentanyl and ketamine, and maintained by infusion of propofol and ketamine and intermittent injections of fentanyl. Perioperative hypothermia was induced by gradually reducing the temperature of a circulating water mattress underneath the body to 15 degrees C. Additionally, somatosensory evoked potential monitoring was performed and recordings were obtained immediately after induction of anesthesia, and before as well as during cross-clamping of the internal carotid artery. Rectal temperature was reduced to 33.7 degrees C when cross-clamping of carotid artery was carried out, but major changes between before and during the procedure was not observed. All procedures were done uneventfully and gradual rewarming was accomplished by electric blanket. No neurological deficits were observed following recovery from anesthesia. Total intravenous anesthesia with propofol, fentanyl and ketamine may be useful for carotid endarterectomy under hypothermia and somatosensory evoked potential monitoring. This method may provide neuronal protection against ischemia injuries induced by cross-clamping of the carotid artery.

Aged↗
PubMed1983

Long-latency somatosensory evoked potentials during carotid endarterectomy.

Scalp recorded somatosensory evoked cortical responses (SSEP) may be measured under general anesthesia to assess the electrical responsiveness of the brain. Such potentials were measured in 25 patients undergoing carotid endarterectomy without shunt. Electrical unresponsiveness occurred bilaterally in one patient and unilaterally in one patient. The patient with unilateral electrical silence developed a perioperative stroke, the only stroke in this series. Analysis of the SSEPs recorded from these patients suggests that profound ischemia produces electrical silence: that intermediate degrees of ischemia produce prolonged interpeak latencies and decreasing amplitudes in the SSEP. This modality seems to offer promise as an intraoperative monitor during cerebrovascular surgery.

Carotid Arteries↗
PubMed1992

[Evolution of post-traumatic hematoma of the liver monitored by ultrasonography].

The results of 20 months of follow-up of posttraumatic hepatic haematoma are presented. The haematoma developed as a result of blunt abdominal trauma and was diagnosed intraoperatively. Monitoring was based on ultrasonography. A significant change in the echographic pattern and size of the haematoma indicated its organization. The purpose of the study was calling attention to the ultrasonographic findings in hepatic haematoma in relation to the time after trauma. It is worth stressing that hepatic haematoma healed well although it had not been managed during the operation (even not drained).

Abdominal Injuries↗
PubMed1990

Spinal cord monitoring during intraspinal extramedullary tumor operations (peroneal nerve evoked responses).

Longterm scalp recording of early SEP components triggered by peroneal or tibial nerve stimulation detects functional disturbances of spinal cord transmission due to mechanical trauma. We confirm previous observations that preoperative SEP patterns reflect neurological deficits and clearly show functional disturbances even on the side where they are not manifest. Peroneal nerve SEP have a well-known P40-peak corresponding to activities of neurons at the postcentral cortical layers. The P40-peak was identified in only 55% of our recordings. We therefore, tried to use the P50-peak that could be identified in 100% of the recordings under the difficult recording circumstances in the operating room. Other authors demonstrate that the P40 component varies spontaneously about 7 ms during operations; we found variation of P50-latencies of 9 ms. We found the P50 component to be a valid and reproducable SEP event for intraoperative monitoring. Decline of SEP amplitudes during the operation occurred especially during dissection of the tumor. We once found intermittent loss of the P50 component with complete recovery after several minutes. This study shows that peroneal nerve SEP monitoring during intraspinal tumor operations is a feasible and valid measure. It provides the surgeon with a new alarm parameter for spinal cord lesions.

Adult↗
PubMed2006

Intraoperative applications of the H-reflex and F-response: a tutorial.

Traditional intraoperative monitoring of spinal cord function involves the use of three techniques: 1. Orthodromic ascending somatosensory evoked potentials (SSEPs) and 2. antIDromic descending neurogenic somatosensory evoked potentials (DNSSEPs) monitor long-tract sensory function. SSEPs and DNSSEPs do not monitor interneuronal gray matter function. 3. Transcranial motor evoked potentials (TMEPs) monitor descending long-tract motor function and measure interneuronal gray matter function by activating motor neurons. TMEPs activate from 4-5% of the motor neuron pool. When using TMEPs 95-96% of the motor spinal cord systems activating the motor neurons are not monitored. Our ability to interact with our environment involves not only intact sensation and strength, but also complex coordinated motor behavior. Complex coordinated motor behavior is controlled by groups of electrically-coupled spinal cord central pattern generators (CPGs). The components of CPGs are: descending and propriospinal systems, peripheral input, and segmental interneurons. The point-of-control is the level of excitation of interneurons, which is determined by the integrated activity of the other components. Spinal cord injury (SCI) changes segmental reflex gain by uncoupling these components. Changes in gain are detected by recordings from muscles. SSEPs, DNSSEPs and TMEPs provIDe limited information about the status of CPGs. H-reflexes measure the function of from 20-100% of the motor neuron pool. F-responses measure the function of from 1-5% of the motor neuron pool. H-reflexes and F-responses provIDe information about the degree of coupling between CPG components. Recording H-reflexes and F-responses together with SSEPs and TMEPs not only monitors spinal cord long-tract function, but also provIDes a multiple-systems approach that monitors those spinal cord systems that are responsible for the control of complex coordinated motor behavior. The objective of this paper is to describe how H-reflexes and F-responses can be used to monitor complex coordinated motor behavior.

Diagnostic Techniques, Neurological↗
PubMed1998

Modulation of somatosensory evoked potentials under various concentrations of desflurane with and without nitrous oxide.

Continuous measurement of somatosensory evoked potentials (SEP) by means of characteristic changes in the signal pattern makes it possible to identify cerebral or spinal cord ischemia during critical phases of the operative procedure. A correct interpretation of the measurements is only possible, however, if the influence of drugs acting on the central nervous system is known. The authors were able to show that inhaled anesthetics have an impact on latencies and response amplitudes. This study examined the influence of various concentrations of desflurane on the conduction of SEP of the Median nerve. In addition, the authors determined how the supplementation of nitrous oxide (N2O) influences the stimulus response of the medianus nerve's SEP. Desflurane has been shown to produce dose-dependent increases in SEP latency (data in part for latency N2O: 0.5 minimum alveolar concentration [MAC] = 20.8 +/- 0.9; 1.5 MAC = 22.2 +/- 1.5; 1.5 MAC/N2O= 23.8 +/- 1.5) and decreases in amplitude, whereas cervically recorded subcortical SEP components are minimally influenced by desflurane. When nitrous oxide is added, there were marked reductions in amplitude (p<0.01) of the cortical stimulus response (1.5 MAC = 2.4 +/- 0.9; 1.5 MAC/N2O = 1.1 +/- 1). It can therefore be recommended that supplementation with N2O should be avoided in the presence of low initial amplitudes. Based on the study's results, the use of desflurane (up to 1.0 MAC) seems to be compatible with intraoperative monitoring of median somatosensory evoked potentials.

Anesthesia, Inhalation↗
PubMed2002

The benefit of neurogenic mixed evoked potentials for intraoperative spinal cord monitoring during correction of severe scoliosis: a case study.

STUDY DESIGN: A case report is presented. OBJECTIVE: To present a case in which surgical correction of a severe scoliotic curve caused unilateral loss of neurogenic mixed evoked potential data despite unchanged somatosensory data. SUMMARY OF BACKGROUND DATA: Surgical correction of large scoliotic curves presents a risk to the function of the spinal cord. Multimodality intraoperative neurophysiologic monitoring of the spinal cord is recommended during such procedures. METHODS: A 13-year-old girl with severe double major scoliosis underwent a staged operative procedure for correction of her spine deformity. Intraoperative neurophysiologic monitoring using somatosensory-evoked potentials and neurogenic mixed evoked potentials was performed for each stage. RESULTS: During the final stage (a T4-L5 posterior instrumentation and fusion) left neurogenic mixed evoked potential data were lost approximately 45 minutes after placement of the left-side, correcting rod. The surgeon was warned of the data change. Set bolts were loosened at all fixation points, and the data quickly returned to within normal limits of baseline. Somatosensory data never approached warning criteria at any point during surgery. The patient awakened with no neurologic deficit. CONCLUSIONS: Neurophysiologic monitoring using both somatosensory-evoked potentials and neurogenic mixed evoked potentials is recommended when surgery is performed to correct spine deformity. The Stagnara wake-up test, somatosensory-evoked potentials, and neurogenic mixed evoked potentials are important components of spinal cord monitoring during surgery, and should be used together for optimal protection of neurologic function.

Adolescent↗
PubMed2002

Acoustic neuroma: outcome study.

Three therapeutic modalities have been advocated in the management of acoustic neuromas: observation, surgery, and radiosurgery. Although surgery is still considered conventional treatment, at times the management can be controversial. The objectives of this article are to assess the results of each of these treatment modalities in a tertiary care acoustic neuroma referral setting. The methodology chosen was to group the patients along the initial intent to treat and then to see the results obtained. A total of 51 patients followed in the Skull Base Clinic of the McGill University Health Centre were included. The intent to treat was as follows: observation, 22 patients; surgery, 26 patients; and radiosurgery, 3 patients. The results showed that 50% of those followed by observation demonstrated growth and required surgery or radiotherapy. Surgical results, in terms of facial nerve outcome, varied with tumour size but also improved dramatically with the introduction of facial nerve monitoring and a multidisciplinary approach. In small and medium-size tumours (< 30 mm), intent to treat by observation or by surgery (with intraoperative monitoring) yielded similar results. The limitations of this study are discussed. In the future, a prospective multicentric study may help better in assessing the value of the various management options.

Adult↗