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PubMedDate not supplied

Transesophageal echocardiography in the detection and surgical management of a papillary fibroelastoma of the mitral valve causing partial mitral valve obstruction.

Primary mitral valve tumors are rare. We describe the transesophageal appearances of a papillary fibroelastoma (Lambl's giant excrescence) of the anterior mitral valve leaflet causing partial mitral valve obstruction. Transesophageal echocardiography proved particularly useful in identifying the limited attachment of the tumor to the anterior mitral valve leaflet and excluding its attachment to the interatrial septum. These features helped to exclude the possibility of the tumor being a left atrial myxoma, the primary differential diagnosis of the lesion. Transesophageal echocardiography enabled the planned surgical option to be mitral valve repair and also allowed intraoperative monitoring to assess the results of the surgical repair.

Aged↗
PubMed1998

[Neuromonitoring in the operating room and in the intensive care unit: a neurophysiologic technique for non-neurophysiologists?].

The successfulness of neuromonitoring in the operating room and intensive care unit relies on an adequate choice of the neurophysiological tool (electroencephalogram or evoked potentials), which should correctly target the neural structure at risk, be sensitive to the pathophysiological process feared, and correctly disentangle pathological and non-pathological factors. The neurophysiological information should be coded into a message readily interpretable by non-neurologists and continuous neuromonitoring should be provided.

Humans↗
PubMed2003

The changing role of pediatric electrodiagnosis.

Electrodiagnosis is one of several useful diagnostic tests in infants and children who have anterior horn cell disease, neuropathy, neuromuscular junction disorders, or myopathy. It is also used for intraoperative monitoring in children. For hypotonic infants and for older children with a nonspecific presentation of weakness, EDX may provide direction for more specific diagnostic testing, such as DNA testing with or without muscle biopsy. Genetic testing has an increasingly important role in the diagnosis of children with neuromuscular disorders. Future improvements in motor unit quantitation, which do not require active patient cooperation and require less time than current methodologies, may make EDX more specific and useful for diagnosing neuromuscular disease in children.

Electrodiagnosis↗
PubMed1996

Effects of nitroglycerin infusion on segmental wall motion abnormalities after anesthetic induction.

OBJECTIVES: To assess the effect of intravenous nitroglycerin (NTG) on segmental wall motion abnormalities (SWMAs) and global ventricular function after anesthetic induction in patients undergoing coronary artery bypass grafting (CABG). DESIGN: Prospective study. SETTING: University hospital. PARTICIPANTS: Twenty patients scheduled for elective CABG. INTERVENTIONS: Patients demonstrating SWMAs in at least two myocardial segments after induction received intravenous NTG at 2 micrograms/kg/min. MEASUREMENT AND MAIN RESULTS: Transesophageal echocardiography (TEE) was performed before and after the NTG infusion for analysis of segmental wall motion abnormalities. Mean arterial pressure (MAP), central venous pressure, and pulmonary capillary wedge pressure decreased significantly after NTG infusion, whereas cardiac index and heart rate remained unchanged. End-diastolic area and end-systolic area decreased, and consequently fractional area change increased significantly. Two of 20 patients (10%) showed electrocardiogram evidence of ischemia after induction. After NTG infusion, 15 of 20 patients (75%) showed an increase in a wall motion score more than two points. In these 15 patients with NTG-responsive wall motion abnormalities, the mean ratio of peak early diastolic filling velocity (E) to peak late diastolic filling velocity (A) increased from 0.89 +/- 0.20 to 1.04 +/- 0.25 (p < 0.01) after NTG infusion despite a decrease in filling pressure. Systolic wall thickening improved in segments with poor preoperative function from a pre-NTG value (mean +/- SD) of -1.0% +/- 7.4% to a post-NTG value of 31.4% +/- 24.9% (p < 0.01). CONCLUSIONS: Intravenous NTG improved postinduction SWMAs in 75% of patients with known coronary artery disease. TEE-guided NTG infusion after induction may provide an optimal baseline echocardiogram for monitoring intraoperative myocardial ischemia by improving the reversible portion of postinduction SWMAs.

Aged↗
PubMed2002

Cervical spine involvement in rheumatoid arthritis. A review.

Cervical spine involvement occurs in over half of patients with rheumatoid arthritis (RA). The most common abnormality is atlantoaxial dislocation, followed by atlantooccipital arthritis with cranial settling and by lesions of the lower cervical spine. Cervical spine involvement usually occurs in patients with severe RA. Pain and evidence of spinal cord injury are the main symptoms. The presence of symptoms is not correlated with the severity of radiological abnormalities. Computed tomography and magnetic resonance imaging provide detailed images of the bone and spinal cord lesions. Because the course is unpredictable, conservatively treated patients usually require regular follow-up. Surgery is in order in patients with pain unresponsive to major narcotics or with progressive neurological impairment. The choice between the anterior and the posterior route depends on the experience of the surgical team. It is reasonable to stabilize the spine before the development of cranial settling or major neurological loss (Ranawat's stage III). The good functional results of spinal surgery are frequently overshadowed by major impairments related to severe peripheral joint disease. Safety is acceptable when somatosensory evoked responses are monitored intraoperatively. Surgery can provide substantial improvements in symptoms, particularly pain.

Arthritis, Rheumatoid↗
PubMed2002

Observations on intraoperative somatosensory evoked potential (SEP) monitoring in the semi-sitting position.

BACKGROUND: Former case reports suggest that monitoring of median nerve somatosensory evoked potentials (M-SEP) is unreliable in patients operated in the semi-sitting position due to the occurrence of evoked potential changes unrelated to neurological damage. This study was designed to analyze these changes in greater detail and confirm that these changes are not caused by neurological damage. METHODS: M-SEP monitoring findings of 50 patients with surgery in the semi-sitting position were analyzed and compared with a group of 50 patients who underwent surgery in the supine position. M-SEP amplitudes and latencies at distinct steps of the monitoring procedure were used for further analysis. In 10 of the 50 semi-sitting patients, M-SEP were recorded additionally after surgery with the anesthetized patient in the supine position. RESULTS: Significant M-SEP changes occurred in the semi-sitting patients only. An amplitude loss of greater than 50% on at least one side was observed in 24 patients. The magnitude and the time course of the amplitude loss was considerably variable. A complete loss of the evoked potential was not observed in any case. In all 10 patients, M-SEP recovered completely when recorded in the supine position. CONCLUSIONS: In about half of the patients with M-SEP monitoring in the semi-sitting position, a significant amplitude loss occurs which is unrelated to neurological damage and presumably caused by subdural gas collections. There is no characteristic pattern of M-SEP changes which enables a differentiation of these 'artificial' alterations from true events. The only appropriate criterion to indicate an impending neurological damage in these patients seems to be a complete loss of the M-SEP potential.

Adolescent↗
PubMed2004

Comparative incidence of venous air embolism and associated hypotension in adults and children operated for neurosurgery in the sitting position.

BACKGROUND AND OBJECTIVE: Venous air embolism is a constant threat during neurosurgery performed in the sitting position. No large prospective study has compared the incidence of venous air embolism and associated hypotension between adults and children. METHODS: Four hundred and thirty patients (334 adults, 96 children) scheduled to undergo planned posterior fossa surgery in the sitting position (between January 1989 to December 1994) were studied with end-tidal carbon dioxide monitoring. Intraoperatively, a sudden and sustained decrease in end-tidal carbon dioxide tension of >0.7 kPa was presumed to be due to venous air embolism. Management during the episode was on the established guidelines. Hypotension (decrease in systolic arterial pressure of 20% or more from the previous level) was treated with crystalloids and/or a vasopressor. RESULTS: Capnometry detected a 28% incidence rate of air embolism in adults (93/334) and a 22% incidence rate in children (21/96) (P = 0.29). In both groups, the highest incidence rate of embolism took place during muscle handling (44% of adults versus 38% of children, P = 0.8). Embolic episodes were accompanied by hypotension in 37% of adults (34/93) and in 33% of children (7/21) (P = 0.98). To restore arterial pressure to pre-embolic levels, 53% of adults (18/34) and 43% of children (3/7) were administered vasopressors (P = 0.94). There was no intraoperative mortality. The surgical procedure on one adult was abandoned because of persistent hypotension following the embolic episode. CONCLUSION: The incidence of venous air embolism and consequent hypotension is similar in adults and children.

Adult↗
PubMed1998

Clinical evaluation of tracheal pressure estimation from the endotracheal tube cuff pressure.

OBJECTIVE: Air flow through an endotracheal tube causes a pressure drop across the tube. This pressure drop creates a difference between air pressure measured in the trachea and the pressure measured in the breathing circuit, which can lead to errors when calculating pulmonary mechanics and when setting ventilators. We have developed a method of estimating tracheal pressure from the pressure in the endotracheal tube cuff and tested this system in clinical trials. METHODS: Pressure measurement ports were placed between the Y piece of the ventilator circuit and the ETT connector, in the trachea at the carinal end of the ETT, and in the ETT cuff inflation line. Tracheal pressures and cuff pressures were found at end-inspiration and end-expiration (no flow states) and used to define a linear relationship between cuff pressure and tracheal pressure. Using the estimated tracheal pressure (Ptrach) and the measured pressure at the Y piece of the breathing circuit (PY), the pressure drop across the ETT was found as a function of flow through the tube. Tracheal pressure was then calculated from the flow-dependent pressure drop and PY. Tests of this system were performed in six patients in the operating room and six patients in the intensive care unit. RESULTS: The flow-based tracheal pressure estimates were within 0.7 +/- 0.4 cm H2O of actual tracheal pressure (mean +/- SD). At peak inspiratory pressure the difference averaged 0.5 +/- 0.3 cm H2O. The difference between our estimate of tracheal pressure and actual tracheal pressure was always less than 1 cm H2O. CONCLUSION: The flow-based tracheal pressure estimates were accurate during intermittent spontaneous breathing, but not during spontaneous breathing or with a poorly inflated cuff. The estimates were more immune to noise than the cuff-based estimates of tracheal pressure. The estimates of tracheal pressure measured from the ETT cuff should be accurate enough for clinical use in the operating room.

Adolescent↗
PubMed1997

Robust sensor fusion improves heart rate estimation: clinical evaluation.

OBJECTIVE: To determine if Robust Sensor Fusion (RSF), a method designed to fuse data from multiple sensors with redundant heart rate information can be used to improve the quality of heart rate data. To determine if the improved estimate of heart rate can reduce the number of false and missed heart rate alarms. METHODS: A total of 85 monitoring periods were investigated, 12 from the operating room, 60 from adult ICU and 13 from pediatric ICU. The operating room periods began with induction of anesthesia and ended at the completion of the anesthetic. For the ICU data, four hour blocks of time were studied. For each monitoring period, HR values were recorded at 5 second intervals or less from the ECG, SpO2 and IAC using a SpaceLabs Medical Gateway connected to a SpaceLabs Medical PC2. Fused estimates of HR were derived for every time point using RSF and all results accepted regardless of confidence value. Data were annotated manually to identify the "reference" HR (that HR value most likely to be correct) at all time points. All HR values from the sensors and the fused estimate that were different from the reference HR by more than +/- 5 beats/min were considered inaccurate. For each monitoring period, the total time per hour that data were either inaccurate or unavailable was calculated for each sensor as well as the fused estimates. The total time of false and missed HR alarms was found for all sensors and the fused estimate by comparing the data to thresholds for both high and low HR alarms at 150 bpm, 130 bpm, 110 bpm and 50 bpm, 40 bpm, 30 bpm respectively. RESULTS: The fused estimate of HR was consistently as good or better than the estimate available from any individual sensor. The fused estimates also consistently reduced the incidence of false alarms compared with individual sensors without an unacceptable incidence of missed alarms. DISCUSSION: Redundancy in sensor measurements can be used to improve HR estimation in the clinical setting. Methods like RSF which improve the quality of monitored data and reduce nuisance alarms will enhance the value of patient monitors to clinicians.

Adult↗
PubMed2000

Comparison of a prototype esophageal oximetry probe with two conventional digital pulse oximetry monitors in aortocoronary bypass patients.

OBJECTIVE: Pulse oximetry (SpO2) is the non-invasive standard for monitoring arterial oxygen saturation in patients undergoing anesthesia, but is subject to external interference by motion artifact, peripheral vasoconstriction, and low cardiac output. We hypothesized that oximetry signals could be acquired from the esophagus when peripheral pulse oximetry is unobtainable. Therefore, we tested an esophageal stethoscope which incorporates transverse oximetry photodetectors and emitters in patients undergoing coronary bypass surgery. METHODS: Immediately after induction of general anesthesia in 10 coronary artery bypass (CABG) patients, Criticare and Nellcor digital probes were positioned on the left hand, concurrent with placement of an esophageal SpO2 probe. A computer recorded 5,910 matched oximetry signals every 15 sec during an average of 2.5 hrs. All SpO2 measurements were before, and immediately after non-pulsatile, hypothermic cardiopulmonary bypass. Data represent the percentage (median value [range]) of the total monitored time that a SpO2 value was displayed. RESULTS: The Nellcor (99.8%, range 6.5-100%) and Criticare (99.7%, range 36.6-100%) acquired and displayed saturation signals more frequently (p = 0.003) than the esophageal monitor (75.3%, range 42.1-95.8%). The two standard digital oximeters had a mean difference of 0.9%, with a standard deviation of the differences of 0.9. The esophageal probe had a mean difference of -5.2% and -4.8%, with standard deviation of differences of 8.0 and 7.7 (compared to the Nellcor and Criticare monitors, respectively). A second-generation prototype shielded from electrocautery interference was tested in an additional 4 patients. The shielded prototype displayed signals more frequently (96.7%, range 68.4-100%) than the original esophageal prototype. CONCLUSIONS: Digital pulse oximetry failure is common in CABG patients, probably because of marginal cardiac output and peripheral vasoconstriction associated with hypothermia. Our study could not confirm that esophageal technology, which utilizes the esophagus as a site of transflectance oximetry, was superior to conventional digital pulse oximetry.

Adult↗
PubMed2000

Measurement of endogenous nitric oxide production.

The measurement of exhaled pulmonary nitric oxide concentrations requires that contamination from the upper respiratory tract and inhaled gases be eliminated. This can be achieved with no risk in the clinical setting of intubated patients of all ages in the operating room or intensive care unit. Further modifications of the anesthetic/ventilatory circuit allow for accurate determination of tidal volume and minute ventilation.

Anesthesia, Inhalation↗
PubMed2002

Supratentorial ganglioglioma and epilepsy: postoperative seizure outcome.

Ganglioglioma is increasingly recognized as being a cause of epilepsy. However, controversy still exists regarding the type of surgery required for optimal seizure control. To find out the factors associated with seizure outcome and to clarify treatment guidelines, a retrospective analysis of 29 epileptic patients who had pathologically proven gangliogliomas that were operated on at our institute during a 13-year period, was performed. There were 23 temporal and six extratemporal gangliogliomas, with a mean age of 16.5 years at surgery. Epilepsy was medically intractable in 14 (48.3%) patients. There were 26 temporal and six extratemporal resections including three re-operations. Three patients underwent intracranial electroencephalography (EEG) recordings (invasive monitoring). Intraoperative electrocorticography (ECoG) was performed in four patients. The mean duration of follow-up after surgery was 36.5 months. The Fisher's Exact test (two-tailed) was used to assess the association between the seizure outcome and several preoperative and operative parameters. Surgical treatment rendered most patients (75.9%, 22/29) seizure free. All three patients who underwent re-operation were seizure-free postoperatively. Eleven (47.8%) of the 23 temporal lobe gangliogliomas were associated with cortical dysplasia. Postoperative incomplete seizure control was associated with the presence of cortical dysplasia (p < 0.001). Good seizure outcome is expected in patients with gangliogliomas, despite years of medically intractable epilepsy, once the tumor is resected. Invasive monitoring/intraoperative electrocorticography is recommended for patients with suspected cortical dysplasia on MRI or for the patients with persistent epilepsy after ganglioglioma resection.

Adolescent↗
PubMed2002

Does the EEG during isoflurane/alfentanil anesthesia differ from linear random data?

OBJECTIVE: Bispectral analysis of the electroencephalogram (EEG) has been used to monitor depth of anesthesia. In the majority of publications this has been done using the so called Bispectral (BIS) Index. The exact relation of this index to bispectral quantities like the bispectrum and its normalized version the bicoherence has not yet been published. In case the EEG is a linear random process the bicoherence is trivial. It is a mere constant independent of the EEG frequency. If the signal is a linear Gaussian random process this constant is zero. In this case both the bispectrum and bicoherence are zero. The aim of this study was to determine the proportion of EEG epochs with non-trivial bicoherence during anesthesia with isoflurane/nitrous oxide. METHODS: We reanalyzed 26.4 hr of EEG signal recorded in 8 patients during anesthesia for general abdominal surgery which were stored in digitized form on CD-Rom. The test developed by Hinich for Gaussianity and linearity was applied to these data. The test was validated with various kinds of surrogate data; especially the phase randomized (pr) EEG, synthetic Gaussian random data and the z-component of the Lorenz attractor and its pr version. RESULTS: The proportion of epochs for which a non-trivial bicoherence was detected by the test was as follows: Lorenz data 95%, pr Lorenz data 5%, synthetic Gaussian data 13.8%, pr EEG 5.4%, original EEG 6.2%. CONCLUSION: As expected the test procedure correctly identified for the Lorenz data for 95% of all epochs a non-trivial bicoherence. For the original EEG data we could not find a significant greater percentage of epochs with non-trivial bicoherence than for the pr data and the synthetic Gaussian data. We conclude that the EEG during anesthesia with isoflurane/alfentanil appears to be largely a linear random process.

Alfentanil↗
PubMed2004

Activation of the external anal and urethral sphincter muscles by repetitive transcranial cortical stimulation during spine surgery.

OBJECTIVE: Clinical utility of high intensity repetitive transcranial electrical stimulation (rTES) to elicit a response in external anal and urethral sphincter muscles was investigated in 23 patients undergoing spine surgery. METHODS: During surgery, motor evoked potentials (MEPs) were recorded from external anal sphincter (EAS), external urethral sphincter (EUS), and tibialis anterior (TA) muscles following high voltage rTES under total intravenous anesthesia. RESULTS: No neurologic sequelae occurred during or after the rTES of the motor cortex. Onset latency for the EAS muscle was 20.2 +/- 3.5 msec which was not significant compared to the EUS muscle latency at 19.9 +/- 1.8 msec. The average electrical intensity to evoke EAS response was 789 +/- 78 volts compared to the 831 +/- 11 volts of the EUS muscle. Waveform latency for the TA muscle was robust in all cases while the latencies for EAS and EUS were not always clear. CONCLUSIONS: This preliminary study shows that intraoperative MEP monitoring of the external anal and urethral muscles is feasible method in particular in circumstances where bowel and bladder function are at risk of an inadvertent injury due to surgical manipulation.

Adult↗
PubMed2003

Benefit of using a triple-lumen catheter to monitor left atrial pressure.

BACKGROUND: Left atrial pressure (LAP) monitoring provides a useful option for management of hemodynamic status in pediatric open-heart surgical patients during the postoperative period. PATIENTS AND METHOD: We used a triple-lumen catheter placed into the left atrium transseptally to measure left atrial pressure. Twenty children that were operated on in our clinic are included in this study: 11 males and nine females. A 5-Fr. triple-lumen radio-opaque polyethylene catheter was used for the procedure. After the repair of the primary cardiac defect, the distal end of the catheter was repositioned transseptally and advanced into the left atrium. The proximal and middle line's distal orifices were left in the right atrium. Distal line was used as a left atrial pressure line, the middle line as a central venous pressure line, and the proximal line as a route for fluid infusion or drug administration. RESULTS: No mortality and no catheter-related complication were observed. No failure or complication occurred during withdrawal of the catheter. CONCLUSION: We conclude that this preliminary technique can be a useful and easy way of monitoring LAP, as well as providing central venous access.

Atrial Function, Left↗
PubMed1999

Clinical and electrophysiological assessment of inferior alveolar nerve function after lateral nerve transposition.

Inferior alveolar nerve (IAN) transposition surgery may cause some degree of sensory impairment. Accurate and reproducible tests are mandatory to assess IAN conduction capacity following nerve transposition. In this study subjective (heat, pain and tactile-discriminative tests) and objective (electrophysiological) assessments were performed in 10 patients receiving IAN transposition (bilaterally in 8 cases) in order to evaluate any impairment of the involved nerves one year post-operatively. All patients reported a tingling, well-tolerated sensation in the areas supplied by the mental nerve with no anaesthesia or burning paresthesia. Tactile discrimination was affected the most (all but 1 patient). No action potential was recorded in 4 patients' sides (23.5%); 12 sides showed a decreased nerve conduction velocity (NCV) (70.5%) and 1 side normal NCV values (6%). There was no significant difference in NCV decrease between partial and total transposition sides, if examined separately. Nerve conduction findings were related 2-point discrimination scores, but not to changes in pain and heat sensitivity. These findings show that lateral nerve transposition, though resulting in a high percentage of minor IAN injuries, as determined by electrophysiological testing, provides a viable surgical procedure to allow implant placement in the posterior mandible without causing severe sensory complaints. Considering ethical and forensic implications, patients should be fully informed that a certain degree of nerve injury might be expected to occur from the procedure. Electrophysiological evaluation is a reliable way to assess the degree of IAN dysfunction, especially if combined with a clinical examination. Intraoperative monitoring of IAN conduction might help identify the pathogenetic mechanisms of nerve injury and the surgical steps that are most likely to harm nerve integrity.

Action Potentials↗