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At least 55 records · Page 3Linked to original sources

[Intraoperative monitoring of intact parathyroid hormone (iPTH) in surgery of primary hyperparathyroidism with a new rapid test].

OBJECTIVES: Intraoperative differentiation between adenoma and hyperplasia during surgery for primary hyperparathyroidism (pHPT) is sometimes difficult, but essential for good results. The aim of our study was to evaluate a new highly sensitive electrochemiluminescence immunoassay (ECLIA) for intraoperative monitoring of intact parathyroid hormone (iPTH) following parathyroidectomy as an adjunct for identification of solitary adenoma in patients with pHPT. METHODS: Thirty consecutive patients with pHPT (2 with recurrent pHPT) were examined following a standardized protocol: Immediately before and 5, 10 and 15 min following parathyroidectomy of the enlarged gland, iPTH was measured with a new ECLIA (Roche-Diagnostics, Mannheim, Germany). The results were available within 15-20 min. Besides 20 conventional bilateral neck explorations, parathyroidectomy was carried out in a minimally invasive video-assisted technique (MI-VAP) in 10 patients. RESULTS: Among the 30 patients we found 24 with solitary adenoma (80%), 5 with hyperplasia (17%) and one with a double adenoma (3%). Five minutes after removal of a solitary adenoma the level of iPTH had decreased by 65 (12)% [mean (+/- SD)], after 10 min by 76 (8)% and after 15 min by 81 (8)%. All patients with multiple gland disease could be clearly identified, as iPTH after 15 min did not fall below 50% of basal value. Only after removal of all hyperplastic glands did iPTH decrease to the normal range. Sensitivity and specificity for prediction of a solitary adenoma were 92% and 100% (decline of iPTH more than 50% from baseline value 5 min after parathyroidectomy). In one patient with recurrent pHPT intraoperative sampling from different sites in both internal jugular veins could predict the quadrant of the enlarged gland. Correlation (r) between the results of the quick and the conventional assay, which requires 24 h of incubation, was 0.955. All patients had normal or low calcium levels postoperatively. CONCLUSIONS: (1) Intraoperative monitoring of iPTH with this new quick assay allows safe identification of patients with solitary adenoma during surgery for pHPT. (2) It represents a valuable adjunct to surgical skill not only in primary operations for pHPT but especially in cases of recurrent surgery for pHPT. (3) With this test available minimally invasive techniques for parathyroidectomy may be employed in cases of preoperatively localized adenoma (ultrasound, sesta-mibi scan), avoiding bilateral neck exploration with its higher potential for complications.

Adenoma↗

Intraoperative monitoring of cerebral blood flow during ventricular shunting in hydrocephalic pediatric patients.

Several studies have demonstrated lowered cerebral blood flow (CBF) in patients with hydrocephalus and symptoms of raised intracranial pressure. Ventricular shunting in such cases permits a sudden increase in CBF. The pathophysiology of functional brain deficit secondary to hydrocephalus is little understood. Improvement of the patient's clinical status after drainage of CSF suggests that cerebral dysfunction is not necessarily due to permanent brain damage. In fact, it improves rapidly after ventricular taps. In view of this it would be helpful to monitor cerebral perfusion. The transcranial Doppler (TCD) ultrasonography technique allows real-time monitoring of the intracranial circulation and makes it possible to evaluate the physiopathological correlation between ventricular dilatation and CBF. Continuous monitoring of the middle cerebral artery (MCA) by TCD was performed in three hydrocephalic children (2 months, 14 months, and 8 years old) during a ventricular-peritoneal shunt operative procedure. A TC-2000S device provided by an IMP-F fixed probe was utilized. In all patients, when the lateral ventricle was shunted and the CSF could flow away, a clear and sudden increase of flow velocity above 30% was detected. The pulsatility index (PI) was also pathologically increased in all patients. A gradual normalization of this index was revealed after the shunting procedure. Our experience has to be considered preliminary, but nonetheless, it suggests a clear correlation between hydrocephalic disease and concomitant CBF alterations.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Flow Velocity↗

The use of intraoperative monitoring and treatment of symptomatic microemboli in carotid artery stenting: case report and discussion.

Carotid artery stenting is a recently introduced treatment in symptomatic atherosclerotic carotid artery disease with acceptable complication rates. The major risk is perioperative embolic stroke. Transcranial Doppler ultrasonography (TCD) can be used to identify embolic signals and guide therapy. We present a case of symptomatic embolization in a 72-year-old female following carotid stent deployment complicated by haemodynamic changes. Despite concurrent dual antiplatelet medication significant symptomatic embolization occurred even after restoration of the blood pressure, and modulation of the rate of embolization was achieved using dextran-40 guided by TCD monitoring. The patient recovered from an initially profound hemiparesis and dysphasia to minor sensory changes. Microemboli are common following carotid artery stenting and there appears to be a threshold phenomenon associated with prolonged embolization and progression to cerebral infarction. TCD can be used to detect particulate microemboli and therefore may be useful in guiding antithrombotic therapy in this setting. Dextran-40 has been shown to reduce the embolic load following carotid endarterectomy and was used to good effect in this patient in terms of both embolic load and clinical outcome. This is the first case of embolization following carotid stenting successfully treated with dextran-40, and offers a further option for therapeutic intervention in microembolism detected by TCD and stresses the importance of perioperative monitoring of embolic load for postoperative stroke risk.

Aged↗

Transcranial Doppler intraoperative monitoring during carotid endarterectomy: experience with regional or general anesthesia, with and without shunting.

To determine whether continuous transcranial Doppler (TCD) can significantly alter therapeutic conduct during carotid endarterectomy, a retrospective study of 117 carotid endarterectomies was done. There was no perioperative mortality; one perioperative stroke was recorded in a patient who was symptomatic preoperatively. Continuous TCD of the ipsilateral middle cerebral artery (MCA) was attempted in 99 cases, and successful in 90; nine patients (9.1%) had inadequate temporal windows for MCA access. MCA velocities and emboli were recorded before and during carotid cross-clamping, and on clamp release. There were no significant velocity differences between the patients with regional and general anesthesia, and patients with and without carotid shunts, but there was a statistically significant difference in the total number of emboli (air and particulate transients) noted for the shunted and nonshunted patients after clamp release: 12.7 versus 23.6, respectively (p = 0.05). There was no significant difference when particulate and air microemboli were compared. During surgery TCD identified residual flow of less than 40% in the MCA in 17 patients (18.8%). TCD also identified hyperperfusion in two patients, shunt abnormalities in three patients, and influenced postop treatment in four patients, one of whom was returned to surgery. TCD is an important tool for identifying patients who would benefit from a shunt, preventing hyperperfusion, identifying postop emboli, and detecting technical errors.

Aged↗

Combined motor and somatosensory evoked potentials for intraoperative monitoring: intra- and postoperative data in a series of 69 operations.

The primary objective of neurophysiologic monitoring during surgery is to avoid permanent neurological injury resulting from surgical manipulation. To prevent motor deficits, either somatosensory (SSEP) or transcranial motor evoked potentials (MEP) are applied. This prospective study was conducted to evaluate if the combined use of SSEP and MEP might be beneficial. Combined SSEP/MEP monitoring was attempted in 100 consecutive procedures, including intracranial and spinal operations. Repetitive transcranial electric motor cortex stimulation was used to elicit MEP from muscles of the upper and lower limb. Stimulation of the tibial and median nerves was performed to record SSEP. Critical SSEP/MEP changes were defined as decreases in amplitude of more than 50% or increases in latency of more than 10% of baseline values. The operation was paused or the surgical strategy was modified in every case of SSEP/MEP changes. Combined SSEP/MEP monitoring was possible in 69 out of 100 operations. In 49 of the 69 operations (71%), SSEP/ MEP were stable, and the patients remained neurologically intact. Critical SSEP/ MEP changes were seen in six operations. Critical MEP changes with stable SSEP occurred in 12 operations. Overall, critical MEP changes were recorded in 18 operations (26%). In 12 of the 18 operations, MEP recovered to some extent after modification of the surgical strategy, and the patients either showed no (n = 10) or only a transient motor deficit (n = 2). In the remaining six operations, MEP did not recover and the patients either had a transient (n = 3) or a permanent (n = 3) motor deficit. Critical SSEP changes with stable MEP were observed in two operations; both patients did not show a new motor deficit. Our data again confirm that MEP monitoring is superior to SSEP monitoring in detecting impending impairment of the functional integrity of cerebral and spinal cord motor pathways during surgery. Detection of MEP changes and adjustment of the surgical strategy might allow to prevent irreversible pyramidal tract damage. Stable SSEP/MEP recordings reassure the surgeon that motor function is still intact and surgery can be continued safely. The combined SSEP/ MEP monitoring becomes advantageous, if one modality is not recordable.

Adolescent↗

Limitation of temporary vascular occlusion during aneurysm surgery. Study by intraoperative monitoring of cortical blood flow.

The limitations of temporary vascular occlusion during aneurysm surgery as evidenced by the postoperative ischemic symptoms in relation to cerebral blood flow were studied. Six of the 39 cases had postoperative ischemic neurological deficit. When residual cerebral blood flow was below 15 mL/min/100 g, transient symptoms were seen when temporary clipping was for 10-20 minutes. When more than 20 minutes of clipping was required, irreversible deficits were found. Correlations between residual cerebral blood flow, duration of temporary clipping, and postoperative ischemic symptoms were found. The monitoring of cortical cerebral blood flow is an effective means for determining the limits of temporary vascular occlusion.

Adult↗

The impact of intraoperative monitoring on patient safety.

There is much more to study and learn about prevention of anesthesia complications and how technology may improve the safety and outcome of anesthesia. Large trials have never shown that a specific hemodynamic monitoring technique improves outcome. In controlled situations, oximetry and capnography have demonstrated efficacy in early detection of events that could be harmful during anesthesia. The BIS monitor has been shown to affect early recovery outcomes and possibly be of value in decreasing long-term mortality. Through all the controversy one thing remains constant: the response to information coming from monitors depends solely on the person administering the anesthesia. Aids to practitioner vigilance probably can never be proved to possess independent benefit, but their role in improving practitioner performance cannot be argued.

Anesthesia↗

A comparison between derivation optimization and Cz'-FPz for posterior tibial P37 somatosensory evoked potential intraoperative monitoring.

OBJECTIVE: To compare P37 derivation optimization to Cz'-FPz. METHODS: After induction in 120 patients, monitoring derivations optimized by mapping FPz, Cz, Cz', Pz, C4', C2', C1' and C3'-mastoid to determine the P37 and N37 maximums for use as inputs 1 and 2 were compared to Cz'-FPz. This was repeated later in 35 surgeries. RESULTS: Eleven optimal derivations occurred and usually differed between sides. Input 1 was Cz', Pz, Cz, iCi', or Ci' and input 2 was Cc', FPz, Ci' or Pz. Even the most frequent Cz'-Cc' derivation was optimal for both sides of an individual in only 17% and this was true for Cz'-FPz in only 4%. Optimization produced higher amplitudes than Cz'-FPz (P<0.001). The ratio was [squareroot of 2] : 1 in 61% of patients and > or =2:1 in 28%, approximately halving or quartering averaging times. Optimization assessed decussation, disclosing non-decussation in one patient while Cz'-FPz did not. Alterations of P37 topography that reduced initially optimal derivation amplitude and made a different derivation optimal were demonstrated by repeat optimization in 13 of 35 patients, preventing misinterpretation in one. While also affected, Cz'-FPz neither detected nor adjusted for potentially misleading topographic changes. CONCLUSIONS: Higher amplitudes, decussation assessment and topographic adjustment make P37 derivation optimization superior to Cz'-FPz for monitoring this highly variable potential.

Adolescent↗