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PubMed1998

Investigation of intraoperative brain deformation using a 1.5-T interventional MR system: preliminary results.

All image-guided neurosurgical systems that we are aware of assume that the head and its contents behave as a rigid body. It is important to measure intraoperative brain deformation (brain shift) to provide some indication of the application accuracy of image-guided surgical systems, and also to provide data to develop and validate nonrigid registration algorithms to correct for such deformation. We are collecting data from patients undergoing neurosurgery in a high-field (1.5 T) interventional magnetic resonance (MR) scanner. High-contrast and high-resolution gradient-echo MR image volumes are collected immediately prior to surgery, during surgery, and at the end of surgery, with the patient intubated and lying on the operating table in the operative position. In this paper we report initial results from six patients: one freehand biopsy, one stereotactic functional procedure, and four resections. We investigate intraoperative brain deformation by examining threshold boundary overlays and difference images and by measuring ventricular volume. We also present preliminary results obtained using a nonrigid registration algorithm to quantify deformation. We found that some cases had much greater deformation than others, and also that, regardless of the procedure, there was very little deformation of the midline, the tentorium, the hemisphere contralateral to the procedure, and ipsilateral structures except those that are within 1 cm of the lesion or are gravitationally above the surgical site.

Adult↗
PubMed1993

Morphine does not affect the awakening concentration of sevoflurane.

This study was designed to determine whether morphine 0.1 mg.kg-1 i.v. given intraoperatively altered the end-tidal concentration of sevoflurane which is associated with eye opening to verbal command. We studied 24 healthy ASA physical status I patients to determine whether morphine, or placebo administered about 60 min before the end of surgery affected recovery from sevoflurane/oxygen anaesthesia. During anaesthesia no other anaesthetics or drugs were given. After surgery, end-tidal sevoflurane concentration was reduced gradually at the rate of less than 0.01%.min-1. The end-tidal concentration at the time patients could respond to verbal command was recorded as MACawake. The MACawake was 0.58 +/- 0.12% (mean +/- SD) for the control group to whom placebo had been administered, and 0.57 +/- 0.11% for morphine group to whom morphine had been administered. In both groups, the MACawake decreased with age, and the ratio to age-adjusted sevoflurane MAC was 0.31 +/- 0.04 (mean +/- SD) for the control group and 0.30 +/- 0.04 for the morphine group. The ratio had no correlation with age. It is concluded that the awakening concentration of sevoflurane during recovery from anaesthesia is not affected by analgesic doses of morphine 0.1 mg.kg-1 i.v. administered intraoperatively.

Adult↗
PubMed2006

Anesthesia for functional neurosurgery: review of complications.

The use of functional stereotactic neurosurgery is increasing for treatment of patients with movement disorders and other chronic illnesses. The anesthetic considerations include the influence of the anesthetic agents on the microelectrode recordings and stimulation testing of an awake patient. The purpose of this study was to review the anesthetic management and incidences of intraoperative complications during functional neurosurgery in our institution. One hundred seventy-eight patients underwent an ablative procedure (n = 6) or the insertion of deep brain stimulator (n = 172) under monitored anesthesia care for movement disorders (n = 124), chronic pain (n = 20), and other procedures (n = 34). Local anesthetic was used for head frame pin sites and burr holes. No sedation/analgesia was administered to 57 (32%) patients. One patient required conscious sedation and another general anesthesia for the entire procedure. The remainder received small increments (mean +/- SD) of propofol (113 +/- 73 mg), midazolam (1.6 +/- 0.8 mg), and/or fentanyl (93 +/- 55 mug). Intraoperative complications that occurred in 16% of the patients included seizures (n = 8), change in neurologic status (n = 5), airway obstruction (n = 2), and hypertension (n = 7). Functional neurosurgery can be performed with minimal anesthesia in many patients. Awareness and vigilance can improve the identification and early treatment of intraoperative complications such as seizures, loss of airway, and changes in the neurologic status.

Adult↗
PubMedDate not supplied

Intraoperative disruption of a Greenfield vena cava filter.

A case illustrating fracture and translocation of a Kim-Ray Greenfield filter strut due to intraoperative manipulation of the filter during cholecystectomy is presented. Awareness of this previously unreported complication is essential in preventing its occurrence.

Adult↗
PubMed2006

Induction of hypothermia after intraoperative hypoxic brain insult.

Hypoxic brain injury can be a devastating complication of anesthesia. Fortunately, it has become increasingly rare. Here we report a case of suspected intraoperative hypoxic brain injury treated with moderate hypothermia. Anesthesiologists should be aware of the option of using this therapy and how to employ it in the setting of suspected hypoxic brain injury.

Female↗
PubMed1987

The lack of response to suggestion under controlled surgical anesthesia.

Thirty-two ASA I or II women undergoing abdominal hysterectomy were randomly allocated to four groups to determine what type, if any, of recorded intraoperative message they would receive. Groups I and II heard a neutral recording with no verbal content. Group III heard an experimental recording with a positive suggestion for a rapid recovery. Group IV had a self-prepared message. The tapes were played during general anesthesia when anesthetic depth was judged to be stable and adequate by vital signs, end-tidal anesthetic concentration and EEG compressed spectral array. No patient reported any recall of intraoperative messages when interviewed on the day after surgery. Chart review showed no difference in days of hospitalization, dose of analgesics required, time to beginning oral intake, or the amount of wound drainage (P greater than 0.05). We conclude that no awareness can be observed directly by recall or indirectly by response to suggestion given under stable and adequate general anesthesia.

Adult↗
PubMed1990

[Conscious and unconscious awareness during anesthesia--how deep is the patient's sleep?].

A review is given over the aspects of awareness during general anaesthesia. Traditional clinical signs for evaluating depth of anaesthesia can be supplemented by objective methods such as EEG, cerebral function monitor and sensory evoked potentials. However, it has been difficult to establish the practical applications of these methods. Awareness can be graded from the obvious form, with recall of intraoperative events, to an unconscious form where the memory can be activated through special psychological techniques. We discuss the possibility of using unconscious perception of auditory signals for positive instructions to patients under anaesthesia.

Anesthesia, General↗
PubMed2006

[Awareness during anesthesia with sevoflurane: a case report].

We report a case of a patient who experienced awareness during general anesthesia with sevoflurane. A 71-year-old man, weighing 57 kg, was operated on for a malignant tumor of the parotid gland. He was given 2 mg diazepam orally as a premedication. General anesthesia was induced by thiamylal 200 mg, fentanyl 50 microg, and up to 5% of sevoflurane. Muscle relaxation was obtained with vecuronium 6 mg, and the patient was intubated. After induction, fentanyl 150 microg was added, but no other intravenous anesthetics or muscle relaxants were used. The end-expiratory concentration of sevoflurane was maintained at 0.8% to 1.7% before the start of surgery, and 1.5% to 2.9% during surgery. The operation lasted for 10.4 hours. His left eye was guarded by ointment but kept open for observation by the surgeon of facial movement following muscle stimulation. The surgical course, emergence, and the postoperative course were uneventful. On the fifth postoperative day, the patient started to describe his visual memory during the operation, although he did not remember any pain or discomfort. We believe that visual input through his open eyes, the effect of cranial bone oscillation by the surgery, and the idiosyncrasy of the patient contributed to his intraoperative recall.

Acoustic Stimulation↗
PubMed1997

Intraoperative anaphylaxis due to allergy to latex in children who have cerebral palsy: a report of six cases.

Healthcare professionals caring for children with cerebral palsy should be aware of an association between it and latex anaphylaxis. Between 1989 and 1992 we had 22 patients with intraoperative anaphylactic reactions to latex at our institutions. Of these, six had cerebral palsy. The case histories of these six children are reported here. Most had had multiple operations and ventriculoperitoneal shunts. Preoperative recognition is key to prevention. If suspected from a patient's history, latex antibody testing is available. If needed, anesthesia for these individuals should be given using a latex-free environment with or without medical prophylaxis.

Adolescent↗
PubMed2006

Postoperative segmental C5 palsy after cervical laminoplasty may occur without intraoperative nerve injury: a prospective study with transcranial electric motor-evoked potentials.

STUDY DESIGN: Intraoperative neurophysiologic monitoring with transcranial electric motor-evoked potentials was performed on patients who underwent cervical laminoplasty at a university hospital in a prospective study. OBJECTIVE: To evaluate the usefulness of intraoperative spinal cord monitoring with transcranial electric motor-evoked potentials for prediction of the occurrence of segmental motor paralysis after cervical laminoplasty. SUMMARY OF BACKGROUND DATA: Segmental motor paralysis occasionally occurs among patients who undergo expansive laminoplasty for cervical myelopathy, and it has been attributed to nerve root lesions caused by either a traumatic surgical technique or a tethering effect after decompression. METHODS: Sixty-two consecutive patients (47 men and 15 women; mean age 64 years [range 32-89]) who were scheduled to undergo cervical laminoplasty under intraoperative spinal cord monitoring with transcranial electric motor-evoked potentials were included in this study. Transcranial electrical stimulations were delivered through pin-type electrodes, and the evoked potentials were recorded over the deltoid, biceps, and triceps muscles in the bilateral upper extremities and thoracic spinal cord. RESULTS: Intraoperative evoked potentials were successfully recorded in all muscles in 57 patients (92%), and incomplete evoked potentials were recorded in the remaining 5 patients. No critical decrease in the amplitude of the evoked potentials was observed in any of the 62 patients. All patients showed sufficient postoperative recovery from their clinical symptoms; however, postoperative transient C5 palsy occurred in 3 patients. CONCLUSIONS: No abnormalities were observed on transcranial electric motor-evoked potential monitoring, even in those patients who developed postoperative transient C5 palsy. These results suggest that the development of postoperative C5 palsy after cervical laminoplasty is not associated with intraoperative injury of the nerve root or the spinal cord, although the precise mechanism of its development is still unclear. Surgeons should be aware that C5 palsy is a possible complication of cervical laminoplasty, even in the absence of intraoperative nerve injury.

Adult↗
PubMed1991

[Acoustic evoked potentials of medium latency and intraoperative wakefulness during anesthesia maintenance using propofol, isoflurane and flunitrazepam/fentanyl].

Auditory evoked potentials have been used as an indicator of awareness. During combined local and general anesthesia clinical signs of adequate anesthesia are difficult to evaluate. In the present study we combined peridural analgesia with three techniques of general anesthesia. Intraoperative wakefulness was documented and correlated with cardiocirculatory parameters as well as with mid-latency auditory evoked potentials (MLAEP). METHODS. After institutional approval and informed consent 30 patients undergoing elective laparotomy were studied as follows: first, continuous peridural analgesia was instituted in all patients to block painful sensation of surgical stimuli and the anesthetic level was maintained at T5. Then general anesthesia was induced with propofol 2.5 mg/kg i.v. (group I, n = 10), thiopental 5 mg/kg i.v. (group II, n = 10), or etomidate 0.2 mg/kg i.v. (group III, n = 10) and maintained with propofol 3-5 mg/kg per hour i.v. (group I), isoflurane 0.4-0.8 vol.-% (group II), or flunitrazepam 0.005-0.01 mg/kg i.v. and fentanyl 0.0025-0.005 mg/kg i.v. bolus injections every 20-30 min (group III). Heart rate and arterial pressure were registered continuously. Purposeful movements of the limbs, eye-opening, or other movements as well as coughing were documented as signs of intraoperative wakefulness. AEP were recorded in the awake state, after induction, and during maintenance of general anesthesia. Latencies of the peaks V, Na, and Pa were measured. By fast-Fourier transformation corresponding power-spectra were calculated to analyze the energy content of the AEP frequency components. RESULTS. Intraoperative wakefulness occurred statistically significantly more often in the patients of group III than in those of groups I and II. There was no correlation between wakefulness and cardiocirculatory parameters. Latencies of peaks V, Na, and Pa in the awake patients were in the normal range; the corresponding power-spectra had their major energy content in the 30-40-Hz range. After induction of general anesthesia with propofol, thiopentone, and etomidate as well as during maintenance of general anesthesia with propofol and isoflurane peak latencies of Na and Pa increased, frequencies in the 30-40 Hz range became suppressed, and MLAEP energy maxima shifted to the low-frequency range. In contrast, during maintenance of general anesthesia with flunitrazepam/fentanyl peak latencies of Na and Pa returned to awake values and frequencies in the range of 30 Hz regained energy dominance in the corresponding power-spectra. CONCLUSIONS. The maintenance of MLAEP and the primary cortical complex Na/Pa correlates with the incidence of motor signs of wakefulness. During the combination of regional and general anesthesia, isoflurane and propofol seem to provide better suppression of intraoperative wakefulness than bolus injections of flunitrazepam/fentanyl.

Adult↗
PubMed1990

[Awareness in total intravenous anesthesia].

After total intravenous anesthesia with propofol for suspension laryngoscopy the patient recalled intraoperative events. There were no obvious clinical signs during the supposed anesthetic course to warn the anesthetist that the fully relaxed patient might not be unconscious.

Adult↗
PubMed2000

Adverse reactions to isosulfan blue during selective sentinel lymph node dissection in melanoma.

BACKGROUND: Selective sentinel lymph node (SLN) dissection can spare about 80% of patients with primary melanoma from radical lymph node dissection. This procedure identifies the SLN either visually by injecting isosulfan blue dye around the primary melanoma site or by handheld gamma probe after radiocolloid injection. METHODS: During selective SLN mapping, 1 to 5 ml of isosulfan blue was injected intradermally around the primary melanoma. From November 1993, to August 1998, 406 patients underwent intraoperative lymphatic mapping with the use of both isosulfan blue and radiocolloid injection. Three cases of selective SLN dissection, in which adverse reactions to isosulfan blue occurred, were reviewed. RESULTS: We report three cases of anaphylaxis after intradermal injection with isosulfan blue of 406 patients who underwent intraoperative lymphatic mapping by using the procedure as described above. The three cases we report vary in severity from treatable hypotension with urticaria and erythema to severe cardiovascular collapse with or without bronchospasm or urticaria. CONCLUSIONS: In our series, the incidence of anaphylaxis to isosulfan blue was approximately 1%. Anaphylaxis can be fatal if not recognized and treated rapidly. Operating room personnel who participate in intraoperative lymphatic mapping where isosulfan blue is used must be aware of the potential consequences and be prepared to treat anaphylaxis.

Adult↗
PubMed1991

Intra-anesthetic awareness.

Awareness during anesthesia is as old as anesthesia itself. Using muscle relaxing drugs, operations can be done on a relaxed but fully aware patient. The problem of intra-anesthetic awareness still exists despite the advances in anesthetic drugs and monitoring. This article reviews the subject from some aspects including its causes, signs, tests and medico-legal points. Awareness during anesthesia can be looked at as 'the invisible scars of surgery.'

Anesthesia, General↗