Ramesh Babu

The Effect of Dexmedetomidine on Perioperative Hemodynamics in Patients Undergoing Craniotomy

BACKGROUND: The perioperative course of patients undergoing intracranial surgery is frequently complicated by hypertensive episodes. Dexmedetomidine (DEX), an &agr;-2 adrenoreceptor agonist, is gaining popularity in neuroanesthesia, because its sympatholytic and antinociceptive properties may improve hemodynamic stability at critical moments of surgery. We designed this study to assess the efficacy of DEX in controlling hypertensive responses in patients undergoing intracranial surgery. METHODS: Patients scheduled for elective craniotomy were randomly assigned to receive either sevoflurane–opioid or sevoflurane–opioid–DEX anesthesia. Bispectral index was used to maintain a similar level of hypnosis in both groups (40–50). Opioids, sevoflurane, and vasoactive medications were titrated in a routine manner, at the discretion of the blinded anesthesiologist managing the case, to maintain systolic blood pressure (SBP) targeted within 90–130 mm Hg and heart rate (HR) between 50 and 90 bpm. Hemodynamic variables were continuously recorded and stored on a computer for analysis. Efficacy of the anesthetic technique in controlling SBP or HR is inversely proportional to the area under the curve (AUC) outside the targeted range. Areas under the curves above and below targeted ranges for SBP-time (AUCsbp mm Hg * min/h) and HR-time (bpm * min/h) were compared. Coefficient of variation was used to assess hemodynamic stability. RESULTS: Seventy-two patients were recruited for the study. Computerized records of 56 patients only were analyzed because of technical problems with data collection in 14 cases. AUCsbp for above the targeted range was significantly lower for patients in the DEX group (P = 0.044). The coefficient of variation for SBP or HR did not differ between groups. A significantly smaller proportion of patients in the DEX group required treatment with antihypertensive medications (12 of 28, 42% vs 24 of 28, 86%, P = 0.0008). The DEX group required fewer opioids in the intraoperative period, but there were no differences in the use of sevoflurane. In the postanesthesia care unit, patients in the DEX group had fewer hypertensive episodes (1.25 ± 1.55 vs 2.50 ± 2.00, P = 0.0114) and were discharged earlier (91 ± 17 vs 130 ± 27 min, P < 0.0001). There were no differences in the requirement for postoperative opioids or antiemetics. CONCLUSIONS: By using indices, which assess a global hemodynamic stability of the anesthetic, we determined that intraoperative DEX infusion was effective for blunting the increases in SBP perioperatively. The use of DEX did not increase the incidence of hypotension or bradycardia, common side effects of the drug.

The effect of intraoperative infusion of dexmedetomidine on the quality of recovery after major spinal surgery.

Background: Surgery induces a variety of metabolic, endocrine, and immune changes collectively known as the “stress response,” which may often lead to prolonged postoperative convalescence. Anesthetic management may modulate this physiological response, thus affecting the postoperative course. We hypothesized that the intraoperative administration of dexmedetomidine (DEX), a sympatholytic agent, would reduce the stress response and improve the quality of recovery in patients undergoing major surgery. Methods: We conducted a prospective randomized double-blinded study of 54 patients undergoing multilevel spinal fusion. Anesthesia was maintained using either propofol/fentanyl/dexmedetomidine (PFD) or propofol/fentanyl/placebo-saline (PFS). The quality of recovery (a primary endpoint) was assessed using a 40-item quality of recovery questionnaire and a 9-question Fatigue Severity Scores. The tests were carried out preoperatively on postoperative days (POD) 1, 2, 3, and 30. Blood samples were collected at baseline, in the postanesthesia care unit, and at POD 1 and were analyzed for levels of cortisol, C-reactive proteins (CRP), and cytokines interleukin (IL)-1&agr;, IL-1&bgr;, IL-1ra, IL-2, IL-6, IL-8, IL-10, and tumor necrosis factor-&agr;. Data were analyzed using SPSS software (version 18) using a multivariate and mixed model approach to test for the effect of surgery and drug group. Pairwise comparisons were assessed by means of the t test or rank tests after correcting for multiple comparisons. Results: The global 40-item quality of recovery questionnaire scores showed a significant effect of time (F4,114=22.63, P<0.001) and drug (F1,51=4.368, P=0.042), with average scores decreasing to lower values on POD 1 (163.63±2.47) and POD 2 (170.94±2.38) compared with baseline (180.56±1.588, mean±SE, 2-tailed t tests, P<0.001). By POD 3, scores were significantly lower (−13.74 point difference, P=0.005) in the PFS group (169.3±3.87) than in the PFD group (183.04±2.76). All patients reported significantly higher levels of fatigue postoperatively, but intergroup difference in Fatigue Severity Scores was detected on POD 3 only, with scores in the PFS group higher than in the PFD group (50.0±4.0 vs. 36.3±4.9, P=0.035). In both groups, plasma cortisol levels were highest in the postanesthesia care unit, whereas CRP levels were elevated on POD 1. DEX significantly reduced the levels of cortisol, but not those of CRP. Levels of cytokines IL-6, IL-8, and IL-10 were significantly higher immediately after surgery and at POD 1. Plasma levels of other cytokines were not affected by surgery. DEX delayed postoperative rise in IL-10 but not in IL-6 or IL-8. Conclusions: DEX infusion during multilevel spinal fusions moderately improved the quality of recovery and possibly reduced fatigue in the early postoperative period. Moreover, it reduced plasma levels of cortisol and IL-10 in comparison with the control group. Our sample size was not sufficient to detect differences either in the incidence of complications or in clinically relevant outcomes.

Evaluation of preoperative administration of the cyclooxygenase-2 inhibitor rofecoxib for the treatment of postoperative pain after lumbar disc surgery.

OBJECTIVE A combination of analgesics with different mechanisms of action may improve postoperative pain control and reduce the incidence of side effects. This study was designed to assess the efficacy of preoperative administration of rofecoxib (Vioxx; Merck & Co., Inc., Somerset, NJ) in reducing pain and opioid requirements after single-level lumbar microdiscectomy. METHODS A randomized, double-blind, placebo-controlled clinical trial was performed on 61 consenting patients who were considered American Society of Anesthesiologists Class I or II and who were scheduled for elective single-level lumbar microdiscectomy. Patients received either two doses of rofecoxib 50 mg or a placebo preoperatively. The outcome measures included morphine use in the postanesthesia care unit (PACU), discharge times, and side effect profile. Data were analyzed by use of independent sample t tests for continuous variables or &khgr;2 tests for categorical variables. A P value of <0.05 was considered significant. RESULTS The two groups were comparable with respect to patient characteristics, intraoperative opioid and hypnotic consumption, and duration of surgery. Patients in the rofecoxib group required significantly less morphine postoperatively. Significantly more patients in the placebo group reported pain scores greater than 7 at admission to the PACU. Time to first request for analgesia was shorter in the placebo group, but the difference did not reach statistical significance. There were no significant differences between groups in the incidence of nausea, time to discharge from the PACU, or hospital stay. CONCLUSION Preoperative rofecoxib is effective in reducing postoperative narcotic consumption in patients undergoing lumbar laminectomy. The use of rofecoxib does not shorten PACU length of stay or hospital discharge time. These outcome measures depend on multiple administrative factors.

Arachnoid cyst of the cerebellopontine angle manifesting as contralateral trigeminal neuralgia: case report.

A case of an arachnoid cyst in the cerebellopontine angle manifesting as contralateral trigeminal neuralgia is presented. Decompression and excision of the lesion resulted in total relief of symptoms. The possible causes of contralateral trigeminal neuralgia are briefly reviewed, and the surgical treatment of this entity is discussed.

Intramedullary abscess associated with a spinal cord ependymoma: case report.

Intramedullary spinal cord abscesses are relatively uncommon. We report the first case of an intramedullary spinal cord abscess in a preexisting spinal cord ependymoma. The clinical features and pathogenesis are discussed. Salient features of the management of intramedullary spinal cord abscesses are outlined.

Schwannoma of the fourth ventricle presenting with hemifacial spasm. A report of two cases.

SummaryTwo cases of cystic brainstem schwannomas protruding into the fourth ventricle are described. Both patients presented with hemifacial spasm. While there is only one previous case report of an intraventricular brainstem schwannoma, there has been no prior description in the literature of hemifacial spasm associated with such a tumor. The clinical, radiographic, surgical, and histopathological features of these tumors are elaborated. The relationship of hemifacial spasm to the various putative theories of origin proposed for intraparenchymal schwannomas is discussed.

Cavernous angiomas of the internal auditory canal A case report and review of literature

SummaryCavernous angiomas of the internal auditory canal (IAC) are rare. They are angiographically occult; and because the clinical symptoms are similar both in intracanalicular cavernous angiomas and acoustic tumors it had been difficult to differentiate pre-operatively both of these pathologies until the advent of magnetic resonance imaging (MRI). Even nowadays the correct diagnosis may be missed if the patient is imaged only with gadolinium enhanced MRI without prior obtaining a non-contrast MRI. These diagnostic difficulties are illustrated by the report of a related case. The importance of thorough neuroradiological investigations stressed and MRI features, surgical management and relevant literature concerning the cavernous angiomas of the internal auditory canal are discussed.

Intramedullary Abscess Associated with a Spinal Cord Ependymoma

Intramedullary spinal cord abscesses are relatively uncommon. We report the first case of an intramedullary spinal cord abscess in a preexisting spinal cord ependymoma. The clinical features and pathogenesis are discussed. Salient features of the management of intramedullary spinal cord abscesses are outlined.

Thoracic paraganglioma presenting with spinal cord compression and metastases.

We report a case of a 41-year-old man with a primary thoracic spine paraganglioma presenting with spinal cord compression and distant metastasis. Paragangliomas arising within the spinal canal are rare and when they occur are usually found in the intradural, extramedullary compartment and in the lumbosacral region. Thoracic paragangliomas are very rare, with only five prior cases reported in the literature and with distant metastasis seen in only one of these. In this case, the tumor was entirely extradural and produced extensive sclerosis of the surrounding vertebrae. The clinical, radiographic, and pathologic features of this case are detailed and the relevant literature is reviewed.

Late radiation necrosis of the brain: Case report

We report a case of radiation necrosis occurring 47 years after resection and radiotherapy for a juvenile pilocystic cerebellar astrocytoma, the longest yet reported. The patient presented with progressive lower cranial nerve dysfunction, and eventually died from cardiopulmonary arrest secondary to aspiration. The presentation, diagnosis, pathological features, and management of radiation necrosis are discussed.