A Case Report of Thalamic Infarction after Lumbar Drain: A Unique Cause of Perioperative Stroke?

In the case presented, a patient has an unexplained episode of hypertension during aneurysm clipping. Following the procedure, the patient was discovered to have bilateral thalamic infarctions unrelated to the vascular location of the aneurysm. After a review of the case, it becomes apparent that intracranial hypotension caused by lumbar over drainage of cerebrospinal fluid (CSF) is the likely cause of both the episode of intraoperative hypertension and the thalamic infarcts. It is often presumed that having an open dura protects against intracranial hypotension and subsequent herniation. We present this case to suggest that opening the dura might not be protective in all cases and anesthesiologists must pay particular attention to the rate of CSF drainage. Lumbar CSF drainage is a technique frequently employed during neurological surgery and it is important for anesthesiologists to understand the signs, symptoms, and potential consequences of intracranial hypotension from rapid drainage.

An epidural blood patch causing acute neurologic dysfunction necessitating a decompressive laminectomy.

OBJECTIVES: One risk with placement of an epidural blood patch (EDBP) is spinal cord or nerve root compression resulting from the epidural blood volume injected, a complication necessitating immediate surgical decompression. We could not find a previous report of this in the literature. Here, we review and discuss one such case. CASE REPORT: A patient was treated with 2 EDBPs for a presumptive cerebrospinal fluid leak 3 weeks after an epidural steroid injection. The second EDBP was performed under direct fluoroscopic guidance, yet resulted in spinal cord compression with radiologic evidence of an epidural hematoma. The patient developed acute cauda equina syndrome and required an emergent decompressive laminectomy resulting in partial resolution of neurological symptoms. One year after the procedure, the patient has recovered most of her motor function but with some persistent numbness below the left knee and a left foot drop. CONCLUSIONS: A cauda equina syndrome from an epidural hematoma may occur as a rare complication of an EDBP, even with direct fluoroscopic guidance. Early diagnosis of symptoms and prompt surgical evacuation of an epidural hematoma is essential and may result in the resolution of symptoms. This complication remains a rare occurrence and should not deter the performance of an EDBP, when indicated.

Cerebral blood flow and the injured brain: how should we monitor and manipulate it?

PURPOSE OF REVIEW: Cerebral ischemia plays a major role in the pathophysiology of the injured brain, including traumatic brain injury and subarachnoid hemorrhage, thus improvement in outcome may necessitate monitoring and optimization of cerebral blood flow (CBF). To interpret CBF results in a meaningful way, it may be necessary to quantify cerebral autoregulation as well as cerebral metabolism. This review addresses the recent evidence related to the changes in CBF and its monitoring/management in traumatic brain injury. RECENT FINDINGS: Recent evidence on the management of patients with traumatic brain injury have focused on the importance of cerebral autoregulation in maintaining perfusion, which necessitates the measurement of CBF. However, adequate CBF measurements alone would not indicate the amount of oxygen delivered to neuronal tissues. Technologic advancements in measurement devices have enabled the assessment of the metabolic state of the cerebral tissue for the purpose of guiding therapy, progress as well as prognostification. SUMMARY: Current neurocritical care management strategies are focused on the prevention and limitation of secondary brain injury where neuronal insult continues to evolve during the hours and days after the primary injury. Appropriately chosen multimodal monitoring including CBF and management measures can result in reduction in mortality and morbidity.

Clinical experience with transcranial Doppler ultrasonography as a confirmatory test for brain death: a retrospective analysis.

BACKGROUND: Transcranial Doppler (TCD) ultrasonography to demonstrate cerebral circulatory arrest (CCA) is a confirmatory test for brain death (BD). The primary aim of this retrospective study was to evaluate the practical utility of TCD to confirm BD when clinical diagnosis was not feasible due to confounding factors. Secondary aims were to evaluate the reasons for inability of TCD to confirm BD and to assess the outcome of patients not brain dead according to the TCD criteria. METHODS: TCD waveforms and medical records of all the patients examined to confirm suspected BD between 2001 and 2007, where clinical diagnosis was not possible, were analyzed. BD was diagnosed based on CCA criteria recommended by the Task Force Group on cerebral death of the Neurosonology Research Group of the World Federation of Neurology. Final outcome of patients and the use of other ancillary tests were noted. RESULTS: Ninety patients (61 males), aged 40 ± 21 (range 3-84) years underwent TCD examination for confirmation of suspected BD. TCD confirmed BD in 51 (57%) patients and was inconclusive in 38 (43%), with no flow signals on the first examination in 7 (8%) patients and the waveform patterns in 31 (35%) being inconsistent with BD. Fourteen of the 19 patients who had CCA pattern in at least one artery but did not meet all the criteria for BD were subsequently found brain dead according to SPECT/clinical criteria or suffered cardiovascular death. CONCLUSION: Using the conventional criteria, TCD confirmed BD in a large proportion, of patients where clinical diagnosis could not be made. The presence of CCA pattern in one or more major cerebral artery may be prognostic of unfavorable outcome, even when BD criteria are not satisfied.

Adenosine-induced transient asystole for intracranial aneurysm surgery: a retrospective review.

UNLABELLED: BRIEF SUMMARY: We describe the use of adenosine-induced cardiac arrest to facilitate intracranial aneurysm clip ligation. BACKGROUND: Cerebral aneurysms are highly variable which may result in difficult surgical exposure for clip ligation in select cases. Secure clip placement is often not feasible without temporarily decompressing the aneurysm. This can be accomplished with temporary clip ligation of proximal vessels, or with deep hypothermic circulatory arrest on cardiopulmonary bypass, although these methods have their own inherent risks. Here we describe an alternate method of decompressing the aneurysm via adenosine-induced transient asystole. METHODS: We examined the records of 27 patients who underwent craniotomy for cerebral aneurysm clipping in which adenosine was used to induce transient asystole to facilitate clip ligation. Duration of adenosine-induced bradycardia (heart rate <40) and hypotension (SBP < 60) recorded on the electronic anesthesia record and outcome data including incidence of successful clipping, intraoperative and postoperative complications, and mortality were recorded. RESULTS: Satisfactory aneurysm decompression was achieved in all cases, and all aneurysms were clipped successfully. The median dose of intravenous adenosine resulting in bradycardia greater than 30 seconds was 30 mg. The median dose of adenosine resulting in hypotension greater than 30 seconds was 15 mg, and greater than 60 seconds was 30 mg. One case of prolonged hypotension after rapid redosing of adenosine required brief closed chest compressions before circulation was spontaneously restored. No other adverse events were observed. CONCLUSIONS: Adenosine cardiac arrest is a relatively novel method for decompression of intracranial aneurysms to facilitate clip application. With appropriate safety precautions, it is a reasonable alternative method when temporary clipping of proximal vessels is not desirable or not possible.

Paradoxical emboli secondary to hepatic pathology: common or coincidental?

Paradoxical cerebral emboli from cardiac and pulmonary sources are well described in the peer-reviewed literature. We outline a case with a hepatic etiology and describe diagnostic and management options. Though this paper represents the first documentation of such, we believe that transpulmonary shunting with concurrent paradoxical cerebral microemboli is more prevalent than recognized. We introduce this case report to compel practitioners to consider paradoxical emboli in selected cirrhotic patients since it can often be difficult to elicit subtle neurologic changes on clinical examination of patients with end stage liver disease.

Postoperative cognitive dysfunction in the elderly.

Despite improvement in surgical techniques, anesthetic management, and intensive care, a significant number of elderly patients develop postoperative cognitive decline. Postoperative cognitive dysfunction (POCD) is a postoperative memory or thinking impairment that has been corroborated by neuropsychological testing, for which increasing age is the leading risk factor. POCD is multifactorial in origin, but it remains unclear whether its occurrence is a result of surgery or general anesthesia. This article discusses the incidence, assessment, consequences, and prevention of POCD, as well as anesthetic strategies to improve cognitive outcome in elderly patients.

Prolonged propofol anesthesia is not associated with an increase in blood lactate.

BACKGROUND: Lactic acidosis is considered an early sign of propofol infusion syndrome. In this study, we investigated the changes in lactate and pH with propofol versus volatile anesthesia (VA) of long duration. METHODS: Demographic and intraoperative data were recorded retrospectively from the anesthesia records of patients who underwent elective spine surgery longer than 8 h. Propofol patients were matched 1:2 to VA patients, based on anesthesia time (AT) (+/-30 min) and blood loss (BL) (+/-500 mL). RESULTS: Of 246 patients identified, 50 received propofol (AT = 10 +/- 2 h, BL = 1955 +/- 1409 mL) and were matched to 100 VA cases (AT = 10 +/- 1 h, BL = 1801 +/- 1543 mL), and of those, 40 and 72 patients, respectively, had complete lactate data at baseline and at 8 h after anesthesia and were included in the main analysis. The propofol group received 8.8 +/- 2 mg x kg(-1) x h(-1) of propofol. The VA group age was older than the propofol group (58 +/- 12 vs 51 +/- 15 yr, respectively, P = 0.002), but there was no difference between the groups in gender, ASA grade, intraoperative hemodynamic variables, and use of vasopressors. After 8 h, the VA group had a larger increase in arterial lactate from baseline compared with the propofol group (change from baseline: propofol, 0.48 +/- 0.72 mmol/L; VA, 1.2 +/- 1.2 mmol/L, P = 0.001). CONCLUSIONS: During prolonged spine surgery >8 h, VA was associated with higher serum lactate, when compared with propofol infusion. Prospective studies are needed to elucidate the exact mechanisms and clinical implications of this finding.

Cerebral autoregulation and anesthesia.

PURPOSE OF REVIEW: This review will examine the recent literature on anesthesia and monitoring techniques in relation to cerebral autoregulation. We will discuss the effect of physiologic and pharmacological factors on cerebral autoregulation alongside its clinical relevance with the help of new evidence. RECENT FINDINGS: Intravenous anesthesia, such as combination of propofol and remifentanil, provides best preservation of autoregulation. Among inhaled agents sevoflurane appears to preserve autoregulation at all doses, whereas with other agents autoregulation is impaired in a dose-related manner. SUMMARY: Intraoperative cerebral autoregulation monitoring is an important consideration for the patients with neurologic disease. Transcranial Doppler based static autoregulation measurements appears to be the most robust bedside method for this purpose.

Accuracy of transcranial Doppler ultrasonography and single-photon emission computed tomography in the diagnosis of angiographically demonstrated cerebral vasospasm.

OBJECT: The goal of this study was to assess the accuracy of the routine clinical use of transcranial Doppler (TCD) ultrasonography and SPECT in predicting angiographically demonstrated vasospasm. METHODS: Following receipt of institutional review board approval, the authors reviewed the records of patients with subarachnoid hemorrhage who had been admitted between 2004 and 2005 and underwent TCD ultrasonography and SPECT evaluations within 24 hours of cerebral angiography. Patients were categorized based on the presence or absence of vasospasm and/or hypoperfusion in the anterior cerebral arteries (ACAs), middle cerebral arteries (MCAs), and basilar arteries (BAs) or posterior cerebral arteries (PCAs) according to each imaging modality. Logistic regression was used to estimate the odds ratio (OR) of an angiographically demonstrated vasospasm also detected on TCD ultrasonography and SPECT. RESULTS: One hundred fifty-two patients (101 women) with a mean age (+/- standard deviation) of 53 +/- 13 years were included in the study. In the ACA, the OR of a vasospasm on TCD ultrasonography was 27 (95% confidence interval [CI] 3-243) and on SPECT 0.97 (95% CI 0.36-2.6); in the MCA, 17 (95% CI 5.4-55) and 2.0 (95% CI 0.71-5.5), respectively; in the BA, 4.4 (95% CI 0.72-27) and 5.6 (95% CI 0.89-36), respectively. There was no substantial change in the relative odds of a vasospasm when the findings on TCD ultrasonography and SPECT were considered jointly. CONCLUSIONS: Transcranial Doppler ultrasonography appears to be highly predictive of an angiographically demonstrated vasospasm in the MCA and ACA; however, its diagnostic accuracy was lower with regard to vasospasm in the BA. Single-photon emission computed tomography was not predictive of a vasospasm in any of the vascular territories assessed.

Esmolol blunts postoperative hemodynamic changes after propofol-remifentanil total intravenous fast-track neuroanesthesia for intracranial surgery.

STUDY OBJECTIVE: To investigate whether esmolol is effective in attenuating postoperative hemodynamic changes related to sympathetic overdrive. DESIGN: Clinical study. SETTING: Operating room of a university hospital. PATIENTS: 60 ASA physical status I, II, and III patients, age 18 to 65 years, scheduled for elective craniotomy for supratentorial neurosurgery. INTERVENTIONS: Patients were given total intravenous anesthesia (TIVA) during emergence from anesthesia and up to 60 minutes after extubation. Those patients who had hypertension (defined as an increase in systolic blood pressure >20% from baseline values) and tachycardia (defined as an increase >20% in heart rate from baseline) received a loading dose of 500 microg/kg esmolol in one minute, followed by an infusion titrated stepwise (50, 100, 200, and 300 microg/kg per min) every two minutes. MEASUREMENTS: The mean dose and duration of esmolol therapy were measured. MAIN RESULTS: Of 60 patients, 49 (82%) who received propofol-remifentanil TIVA developed significant tachycardia and hypertension soon after extubation. Treatment with esmolol (500 microg/kg in bolus maintained at a mean rate of 200 +/- 50 microg/kg per min) effectively controlled hypertension and tachycardia in 45 of 49 patients (92%; P < 0.05) within a mean 4.30 +/- 2.20 minutes. After extubation, mean esmolol infusion time was 29 +/- 8 minutes. CONCLUSION: In patients undergoing elective neurosurgery with propofol-remifentanil TIVA, a relatively small esmolol dose and short infusion time effectively blunts early postoperative arterial hypertension and tachycardia.

Hemispheric differences in cerebral autoregulation in children with moderate and severe traumatic brain injury.

INTRODUCTION: To examine hemispheric differences in cerebral autoregulation in children with traumatic brain injury (TBI). After IRB approval and consent, subjects underwent static cerebral autoregulation testing during the first 9 days after PICU admission. Cerebral autoregulation was quantified using the autoregulatory index (ARI). RESULTS: Forty-two (27 M:15 F) children (10 +/- 5 years) with TBI and admission Glasgow coma scale score (5 +/- 2) were enrolled. Seven (54%) of the 13 children with focal TBI and 8 (28%) of 29 children with diffuse TBI had impairment or absence of cerebral autoregulation of at least one hemisphere. In patients with isolated focal TBI, ARI was lower (0.40 +/- 0.40 vs. 0.67 +/- 0.40; P = 0.03) in the side of TBI than in the unaffected hemisphere, but cerebral autoregulation was often impaired on the side without TBI or shift (5/13) on head CT. There was no difference in ARI between hemispheres in children with diffuse TBI, with or without superimposed focal lesions (P = 0.17). Patients with bilateral intact cerebral autoregulation tended to have higher 6 month Glasgow Outcome Score (GOS) than patients with either unilateral or bilateral cerebral autoregulation impairment (GOS 4.0 +/- 0.60 vs. 3.6 +/- 0.80; P = 0.08). CONCLUSIONS: Hemispheric differences in cerebral autoregulation were common in children with isolated focal TBI. Absence of TBI on CT was not always associated with intact cerebral autoregulation. Patients with bilaterally intact cerebral autoregulation tended to have better outcomes.

Effect of equiosmolar solutions of mannitol versus hypertonic saline on intraoperative brain relaxation and electrolyte balance.

BACKGROUND: The purpose of the study was to compare the effect of equiosmolar solutions of mannitol and hypertonic saline (HS) on brain relaxation and electrolyte balance. METHODS: After institutional review board approval and informed consent, patients with American Society of Anesthesiologists physical status II-IV, scheduled to undergo craniotomy for various brain pathologies, were enrolled into this prospective, randomized, double-blind study. Patients received 5 ml/kg 20% mannitol (n = 20) or 3% HS (n = 20). Partial pressure of carbon dioxide in arterial blood was maintained at 35-40 mmHg, and central venous pressure was maintained at 5 mmHg or greater. Hemodynamic variables, fluid balance, blood gases, electrolytes, lactate, and osmolality (blood, cerebrospinal fluid, urine) were measured at 0, 15, 30, and 60 min and 6 h after infusion; arteriovenous difference of oxygen, glucose, and lactate were calculated. The surgeon assessed brain relaxation on a four-point scale (1 = relaxed, 2 = satisfactory, 3 = firm, 4 = bulging). Appropriate statistical tests were used for comparison; P < 0.05 was considered significant. RESULTS: There was no difference in brain relaxation (mannitol = 2, HS = 2 points; P = 0.8) or cerebral arteriovenous oxygen and lactate difference between HS and mannitol groups. Urine output with mannitol was higher than with HS (P < 0.03) and was associated with higher blood lactate over time (P < 0.001, compared with HS). Cerebrospinal fluid osmolality increased at 6 h in both groups (P < 0.05, compared with baseline). HS caused an increase in sodium in cerebrospinal fluid over time (P < 0.001, compared with mannitol). CONCLUSION: Mannitol and HS cause an increase in cerebrospinal fluid osmolality, and are associated with similar brain relaxation scores and arteriovenous oxygen and lactate difference during craniotomy.